Browse Topic: Environmental regulations and standards

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A-6 Aerospace Actuation, Control and Fluid Power Systems
Ducted Fuel Injection Provides Consistently Lower Soot Emissions in Sweep to Full-Load Conditions03-19-01-00017/14/2023
Abstract Earlier studies have proven how ducted fuel injection (DFI) substantially reduces soot for low- and mid-load conditions in heavy-duty engines, without significant adverse effects on other emissions. Nevertheless, no comprehensive DFI study exists showing soot reductions at high- and full-load conditions. This study investigated DFI in a single-cylinder, 1.7-L, optical engine from low- to full-load conditions with a low-net-carbon fuel consisting of 80% renewable diesel and 20% biodiesel. Over the tested load range, DFI reduced engine-out soot by 38.1–63.1% compared to conventional diesel combustion (CDC). This soot reduction occurred without significant detrimental effects on other emission types. Thus, DFI reduced the severity of the soot–NOx tradeoff at all tested conditions. While DFI delivered considerable soot reductions in the present study, previous DFI studies at low- and mid-load conditions delivered larger soot reductions (>90%) compared to CDC operation at the same conditions. Therefore, the DFI configuration used here has been deemed nonoptimal (in terms of parameters such as the injector-spray and piston geometries), and several improvements are recommended for future studies with high-load DFI. These improvements include employing better spray-duct alignment, a deeper piston bowl with a smaller injector umbrella angle, and a fuel injector that opens and closes faster. The study also suggests future research to make DFI ready for commercialization, such as metal-engine tests to ensure desirable DFI performance over an engine’s complete speed/load map. Overall, this study supports the continued development and commercialization of DFI to meet upcoming emissions regulations for heavy-duty vehicles. Specifically, multicylinder engine experiments and CFD simulations should be utilized to optimize the performance and clarify the full potential of DFI.
Buurman, Noad J., Nyrenstedt, Gustav, Mueller, Charles J.
Engine-in-the-Loop Analysis of the Influence of Manual Gearshift Duration on Vehicle Consumption and Emissions15-16-01-00039/27/2022
Abstract The tightening of emission standards and homologation rules lead car manufacturers to rely on simulation testing in early development phases. Coupling an engine to a testbench controlled by a real-time simulation environment allows flexible, reliable, and reproducible testing for consumption and emission studies. However, interest in this method referred to as engine-in-the-loop (EiL) is relatively recent and few details can be found regarding the simulation environment. Following previous work, this study details a driver model based on the PI structure and augmented with preview and anti-windup. The focus is set on a conventional powertrain with a manual transmission for which the driver must also manage the clutch pedal during gearshift and take-off phases. Extended analysis of vehicle tests allows defining the driver’s behavior during these phases for different profiles. The driver model is then tested in the EiL environment and the impact of the gearshift profile on fuel consumption and pollutant emissions can be assessed. Besides the slight increase in fuel consumption, results show that increasing the gearshift duration degrades the regulation of the richness by the ECU, thus increasing CO engine-out emissions as well as decreasing NOx emissions. Finally, results suggest that a longer gearshift also affects the catalyst efficiency, which results in higher NOx tailpipe emissions.
Gilormini, Thomas, Chessé, Pascal, Tauzia, Xavier, Colin, Hervé
Questions about Real Driving Emissions in BrazilSAE-PP-002272/2/2021
The motor vehicles are the main source of atmospheric pollution, especially carbon monoxide, hydrocarbons and nitrogen oxides (NOx). To reduce these emissions for environmentally acceptable levels, Europe and the United States have developed control programs, where are set emissions limits for new vehicles, which are gradually reduced over time and the compliance must be done through standardized tests in laboratories. However, Europe is facing a problem: NOx level in the cities is not being reduced in the same proportion of the homologation limits, due to two factors: the poor representativeness of the test procedures in comparison of the “real world” and the use of engine management software that produces low pollutants just in laboratory tests. Several studies about real world emissions have pointed to vehicles, approved in the laboratory, emitting in the streets about 7 up to 40 times more NOx than the homologation limit. To fix this problem, since September/2017 Europe will add to the vehicles type-approval process a real driving emissions test (Real Driving Emissions - RDE), where the vehicle must meet the limits when running in streets coupled to a portable measuring system. In order for the RDE procedure be applied effectively to the Brazilian reality, it is necessary to discuss three relevant points: the differences between the national and the European fleet, the procedure itself, focused on NOx control and the specific characteristics of Brazilian cities. This paper has the objective to discuss about RDE principles and how it can to be applied in the Brazilian reality.
Anthony, Lindsay
A New Cavitation Algorithm to Support the Interpretation of LIF Measurements of Piston Rings2020-01-10914/14/2020
Laser induced fluorescence (LIF) is used to investigate oil transport mechanisms under real engine conditions. The engine oil is mixed with a dye that can be induced by a laser. The emitted light intensity from the dye correlates with the residual oil at the sensor position and the resulting oil film thicknesses can be precisely determined for each crank angle. However, the general expectation is not always achieved, e.g. an exact representation of piston ring barrel shapes. In order to investigate the responsible lubrication effects of this behavior, a new cavitation algorithm for the Reynolds equation has been developed. The solution retains the mass conservation and does not use any switch function in its mathematical approach. In contrast to common approaches, no vapor-liquid ratio is used, but one or several bigger bubbles are approximated, as have been observed in other experiments already. As a result, not only the known boundary conditions for the Reynolds equation become unnecessary, but the solution also gives a clearer idea as to the shape of the cavitation bubble. The combination of simulated oil film thicknesses, the resulting cavitation bubbles and the fixed field of view from the LIF sensor allows a reproduction of the measurement signal. The comparison of measurement and simulation exhibits a high correlation, and thus enables a deeper knowledge and understanding of the real conditions inside a combustion engine. On the other hand, it can be seen that effects such as a decrease in the LIF signal in the cavitation area is much lower than would be expected according to the literature.
Ruch, Fabian H., Wachtmeister, Georg
Analysis of Drivability Influence on Tailpipe Emissions in Early Stages of a Vehicle Development Program by Means of Engine-in-the-Loop Test Benches2020-01-03734/14/2020
Due to increasing environmental awareness, standards for pollutant and CO2 emissions are getting stricter in most markets around the world. In important markets such as Europe, also the emissions during real road driving, so called “Real Driving Emissions” (RDE), are now part of the type approval process for passenger cars. In addition to the proceeding hybridization and electrification of vehicles, the complexity and degrees of freedom of conventional powertrains with internal combustion engines (ICE) are also continuing to increase in order to comply with stricter exhaust emission standards. Besides the different requirements placed on vehicle emissions, the drivability capabilities of passenger vehicles desired by customers, are essentially important and vary between markets. As the interactions between different hardware and software parts of the powertrain strongly influence the drivability characteristics of a vehicle, a high degree of maturity of test vehicles is required to execute drivability calibration tasks with a reliable evidence. Hence, these calibration and evaluation tasks are generally conducted in late phases of the vehicle development process where the engines base calibration is already at an advanced level. Thereby, the assessment of the influences of drivability calibration on the vehicle’s tailpipe emissions is complex. Since any changes to the powertrain and exhaust gas aftertreatment systems, except calibration changes, are very expensive and time consuming in late vehicle development phases, drivability related emission analyses and enhancements are usually not carried out or considered separately. Before this backdrop, this article introduces a method to determine and enhance the influence of drivability calibration demands on tailpipe emissions already during early vehicle development phases. The utilization of objectification of the vehicle’s drivability behavior enables frontloading of drivability calibration tasks into phases of investigations on engine test benches. Therefore in this work, a highly dynamic “Engine-in-the-Loop” (EiL) test bench, which is equipped with emission analyzers and operated as part of a virtual co-simulation scenario, is used to compare the individual tailpipe emissions of two regionally different drivability calibration data sets for the same powertrain/vehicle variant. With this technique, the customer and market-specific requirements for longitudinal drivability and their interdependencies on the vehicle’s tailpipe emissions can be considered in early vehicle development phases, in which pilot or final production equivalent vehicles are not yet available. Thus, the risk of expensive late changes during a vehicle development program can be significantly reduced, as base calibration tasks of the combustion engine can already be carried out against the background of the later desired drivability behavior.
Heusch, Christian, Guse, Daniel, Dorscheidt, Frank, Claßen, Johannes, Fahrbach, Timm, Pischinger, Stefan, Tegelkamp, Stefan, Görgen, Michael, Nijs, Martin, Scharf, Johannes
Characteristics of Transient NOx Emissions of HEV under Real Road Driving2020-01-03804/14/2020
To meet the request of China National 6b emission regulations which will be officially implemented in China, firstly including the RDE emission test limits, the transient emissions on real road condition are paid more attention. A non-plug-in hybrid light-duty gasoline vehicles (HEV) sold in the Chinese market was selected to study real road emissions employed fast response NOx analyzer from Cambustion Ltd. with a sampling frequency of 100Hz, which can measure the missing NO peaks by standard RDE gas analyzer now. Emissions from PEMS were also recorded and compared with the results from fast response NOx analyzer. The concentration of NOx emissions before and after the Three Way Catalyst (TWC) of the hybrid vehicle were also sampled and analyzed, and the working efficiency of the TWC in real road driving process was investigated. It is found that when the engine is at high-speed and heavy-load conditions, especially when fuel is injected after fuel cut, instantaneous spikes in tailpipe NO emissions could be observed, which means that traffic positions such as crosswalks, speed bumps, expressway entrances, traffic lights, would lead to higher NOx emissions, because the instantaneous fuel cut-off occurs during the acceleration shifting process, the TWC is in an oxygen-rich state. Obvious transient effects were revealed and the results could be used for further reducing NOx emissions from automotive RDE and engine calibration of RDE.
Zhang, Yonghao, Deng, Jun, Li, Qiang, Liu, Yintong, He, Bo, Hu, Zongjie, Bo, Shi, Li, Liguang
An Experimental Study on the Effect of Exhaust Gas Recirculation on a Natural Gas-Diesel Dual-Fuel Engine2020-01-03104/14/2020
Natural gas (NG)-diesel dual-fuel combustion can be a suitable solution to reduce the overall CO2 emissions of heavy-duty vehicles using diesel engines. One configuration of such a dual-fuel engine can be port injection of NG to form a combustible air-NG mixture in the cylinder. This mixture is then ignited by a direct injection of diesel. Other potential advantages of such an engine include the flexibility of switching back to diesel-only mode, reduced hardware development costs and lower soot emissions. However, the trade-off is lower brake thermal efficiency (BTE) and higher hydrocarbon emissions, especially methane, at low load and/or high engine speed conditions. Advancing the diesel injection timing tends to improve the BTE but may cause the NOx emissions to increase. In this study, exhaust gas recirculation (EGR) is used in combination with the diesel injection timing control to demonstrate the compromises between lowering NOx, soot, and methane emissions while maintaining diesel-like BTE. Determining such optimal operating conditions can not only reduce the consumption of diesel and NG but may also enhance the life of the exhaust after-treatment system components such as the diesel particulate filter (DPF). Tests are performed on a heavy-duty, four-stroke, NG-diesel dual-fuel single-cylinder research engine with independent and flexible air and fuel delivery systems. Two load levels corresponding to 50% and 75% of full load are investigated at a constant engine speed of 1000 rpm and NG-diesel energy ratio of 3:1. Results show that advancing the diesel injection timing at a low EGR ratio (~10% based on intake and exhaust CO2) can reduce the soot and methane emissions but cause the NOx emissions to increase. Further increase of EGR to up to 18% can reduce the NOx emissions while limiting the soot emissions to the heavy-duty regulatory limits. In general, with the use of EGR, dual-fuel combustion can provide an improved NOx-soot trade-off compared to diesel-only combustion.
Dev, Shouvik, Guo, Hongsheng, Lafrance, Simon, Liko, Brian
History and Prospects for Electric Vehicles and Electric Bikes: Pathway to Sustainable Carbon Free Energy and Transportation2020-01-09744/14/2020
The Electric Transportation Revolution (ETR) began with the General Motors USA EV1 project and Yamaha Japan Pedal Assist System (PAS) electric bike, both in 1993. Worldwide EB annual sales are 40 million with 300 million on the road, mostly in China. Mandates and government incentives influence the EV market, customer demand drives EB growth. The EPA CO2 endangerment finding is forcing the auto industry to invest in EVs to help limit Mankind Made Carbon Dioxide Climate Change, MMCDCC, which is based on theoretical computer models that calculate global temperature. Measured temperature data, revised by modelers, used to validate these models has been challenged and so reported. Historical climatology data shows that Natural Climate Change, NCC, is more likely the CC cause. Known periodic variations of the sun’s orbit changes solar radiance and causes NCC. More CO2 in the atmosphere produces more plant growth, more food, thus CO2 is a beneficial gas. We propose a long term pathway to eliminate CO2 as an issue for energy and transportation. Fossil fuels may be depleted in 200 years. During this period, transition worldwide to nuclear power and hydrogen for electricity and transportation is necessary. Nuclear fuels will be used forever as uranium extraction from seawater is now possible and is replenished by runoff from land. Nuclear electricity will produce hydrogen from electrolysis of water for vehicle use. Power plants and vehicles will thus not produce CO2. With this prospect of sustainable carbon free electricity and vehicle fuel, the humanitarian thing to do today is to continue to use fossil fuels for both domains, in order to provide affordable heat in cold winters and cooling in hot summers which occurs in some regions of the world today until nuclear options are developed. This all is likely NCC as it has been for hundreds of millions of years on planet earth, and not MMCDCC.
Jamerson, Frank E.
Vehicle Emission Solutions for China 6b and Euro 72020-01-06544/14/2020
Combinations of CC1 TWC and CC2 coated gasoline particulate filters (cGPF) were aged by 4-mode and fuel cut aging to simulate 200K kilometers of in-use aging in China and Europe, respectively. Separate combinations of catalysts were then evaluated on two low emission engines using the WLTC driving cycle. Catalyst volume and PGM mass were varied in the CC1. OSC/washcoat amounts were varied at constant PGM loading in the GPF. For the Chinese application, after the four-mode aging, it was found that the CC1 TWC catalyst volume should be greater than 1.0 L. High levels of OSC were needed in the GPF to meet CO and NOx emission targets. For the European application, after fuel cut aging, Euro 6d emissions were met with any combination of TWC and GPF catalysts. If the gaseous regulations for Euro 7 are similar to China 6b, the CC1 TWC catalyst should also be great than 1.0 L in order to meet CO and NOx emissions. Over all, results imply that CC1 TWC design is most critical for gaseous emissions. More washcoat (i.e., bigger volume) in the CC1 is more effective for emission reduction than increased PGM. GPFs in the CC2 position may need high OSC/washcoat levels to achieve the CO and NOx emissions regulations for China 6b and Euro 7. The PN measurements for all GPFs were well within current regulations.
Ball, Douglas, Meng, Xiangwei, Weiwei, Gu, Meng, Xiangwei, Weiwei, Gu
Motor Vehicle Emission Control Quality Monitoring for On-Road Driving: Dynamic Signature Recognition of NO x & NH 3 Emissions2020-01-03724/14/2020
Motor vehicle emission testing during on-road driving is important to assess a vehicle’s exhaust emission control design, its compliance with Federal regulations and its impact on air quality. The U.S. Environmental Protection Agency (EPA) has been developing new approaches to screen the characteristics of vehicle dynamic emission control behaviors (its operating signature) while driving both on-road and on-dynamometer. The so-called “signature device” used for this testing is equipped with an O2/NOx sensor, thermocouple and GPS to record dynamic exhaust NOx concentration, air fuel ratio-controlled tailpipe lambda (λ), tailpipe temperature and vehicle speed (acceleration). In the early EPA research, signature screening was used to characterize a vehicle’s PCM control behaviors (cause/effect bijectivity), which help distinguish operation in normal control state-space and abnormal state-space. Currently, signature devices are being used to recognize when ammonia (NH3) has been emitted and to estimate the presence of NOx and NH3 within on-road and on-dyno driving. The presence of NH3 is observed by the signature device’s NOx sensor at times when tailpipe lambda readings are biased rich, after the engine three-way-catalyst (TWC) has warmed up. To study the production of NH3, EPA established a vehicle test program to gather and evaluate the emissions from on-road driving conditions. The same driving conditions were then replicated on an indoor chassis dynamometer (dyno) while using a bag analyzer bench, a raw exhaust modal bench, and a signature device to measure vehicle emissions and control behaviors. EPA ascertained, under certain operating conditions, that stoichiometric engine exhaust passing through a TWC can create hydrogen (CO+H2O→H2), which is then available to produce unregulated ammonia (CO+NO+H2→NH3). These reactions can accelerate when the engine operates with slightly rich-biased lambda introduced either by control or by calibration design. Under current Light-Duty Tier 3 emission regulations, NOx and NMOG emissions are counted together, creating an “opportunity” for more of this type of engine operation.
Tang, Xiaoguo, Kargul, John, McBryde, Dan
Single vs Double Stage Partial Flow Dilution System: Automobile PM Emission Measurement2020-01-03664/14/2020
The US Code of Federal Regulations (CFR) Title 40 Part 1065 and 1066 require gravimetric determination of automobile Particulate Matter (PM) collected onto filter media from the diluted exhaust. PM is traditionally collected under simulated driving conditions in a laboratory from a full flow Constant Volume Sampler (CVS) system, where the total engine exhaust is diluted by HEPA filtered air. This conventional sampling and measurement practice is facing challenges in accurately quantifying PM at the upcoming 2025-2028 CARB LEVIII 1 mg/mi PM emissions standards. On the other hand, sampling a large amount of PM emitted from large size high power engines introduces additional challenges. Applying flow weighting, adjusting the Dilution Ratio (DR) and Filter Face Velocity (FFV) are proposed options to overcome these challenges. The Partial Flow Dilution System (PFDS) technique has been recognized as a viable alternative to the CVS method, to meet the wide range DR and FFV requirements for PM determination from both Light-Duty Vehicles (LDV) and Heavy-Duty Engines (HDE) [4, 5, 6, 7, 8]. In this study, performance of a PFDS for PM measurement with Single Dilution (SD) and Double Dilution (DD) configurations against conventional CVS sampling was investigated. Tests were run on a Cummins heavy-duty 8.9L engine with maximum rated power of 380 HP in an engine test cell. The engine aftertreatment system is comprised of a combined Diesel Oxidation Catalyst (DOC) and Selective Catalyst Reduction (SCR). The reference data, also referred to as historical data, was generated in a test cell using the CVS method. PM measurements were made over the US Non-road Transient Cycle (NRTC) and Ramped Modal Cycle (RMC). The brake-specific particulate matter (BSPM) was calculated using the raw chemical balance utilizing intake airflow measurements and the measurement of gases in the exhaust. The PFDS with single and double tunnel configuration showed good repeatability with a COV of <6% when compared against the historical data which has a COV of <8%. The PFDS with single and double dilution met all the global regulatory requirements with the correlation coefficient of 1.005 and the coefficient of determination (R2) greater than 0.98.
Rahman, Montajir, Rooney, Rick, Nevius, Tim, Otsuki, Yoshinori, Yoshida, Taisuke, Khan, Yusuf, Liew, Chet Mun, Basrur, Chirag
A Demonstration of High Efficiency, High Reactivity Gasoline Compression Ignition Fuel in an On & Off Road Diesel Engine Application2020-01-13114/14/2020
The regulatory requirements to reduce both greenhouse gases and exhaust gas pollutants from heavy duty engines are driving new perspectives on the interaction between fuels and engines. Fuels that reliefs the burden on engine manufacturers to reach these goals are of particular interest. A low carbon fuel with a higher volatility and heating value than diesel is one such fuel that reduces engine-out emissions and carbon footprint from the entire hydrocarbon lifecycle (well-to-wheel) and improves fuel efficiency, which is a main enabler for gasoline compression ignition (GCI) technology. The present study investigated the potential of GCI technology by evaluating the performance of a low carbon high efficiency, high reactivity gasoline fuel in Doosan’s 6L medium duty diesel engine. In the experimental test, it was found that the fuel could provide the same performance in power and torque with the same calibration strategy as diesel, while the fuel efficiency was improved by maximum 4.3%. Overall total hydrocarbon (THC) and particulate matter (PM) emissions were decreased, but nitrogen oxides (NOx) was increased by average 6%. Computational fluid dynamics (CFD) engine simulations were conducted to find the way to suppress NOx emission while maintaining other benefits of the fuel. At the same injection calibration, the experimental observation was reproduced computationally. Fuel injection strategy was further investigated by changing the start of injection (SOI) and splitting the fuel injection into pilot, main and post injections. The used fuel was able to achieve up to 16% of NOx reduction at the same fuel efficiency while maintaining low PM emission. This work demonstrated that a low carbon high reactivity gasoline fuel can improve the fuel efficiency and lower the emissions with minimum modification on engine hardware and calibration in a medium duty diesel engine.
Sim, Jaeheon, Han, Youngdeok, Yoo, Dockoon, Lee, Woong Gun, Chang, Junseok
The Application of E-Fuel Oxymethylene Ether OME1 in a Virtual Heavy-Duty Diesel Engine for Ultra-Low Emissions2020-01-03494/14/2020
For long haul transport, diesel engine due to its low fuel consumption and low operating costs will remain dominant over a long term. In order to achieve CO2 neutrality, the use of electricity-based, synthetic fuels (e-fuels) provides a solution. Especially the group of oxymethylene ethers (OME) is given much attention because of its soot-free combustion. However, the new fuel properties and the changed combustion characteristics place new demands on engine design. Meanwhile, the use of new fuels also creates new degrees of freedom to operate diesel engines. In this work, the application of dimethoxymethane (OME1) is investigated by means of 1D simulation at three operating points in a truck diesel engine. The subsystems of fuel injection, air path and exhaust gas are sequentially adjusted for the purpose of low emissions, especially for low nitrogen oxides (NOx). Thanks to the inexistent soot-NOx trade-off, NOx can be considerably reduced by high exhaust gas recirculation (EGR) at a nearly stoichiometric operation. In addition, conceivable configurations of exhaust after-treatment system are analyzed. At last, a holistic layout of a future OME-powered engine is proposed.
Yang, Qirui, Grill, Michael, Bargende, Michael
Regulated Emissions and Detailed Particle Characterisation for Diesel and RME Biodiesel Fuel Combustion with Varying EGR in a Heavy-Duty Engine2019-01-229112/19/2019
This study investigates particulate matter (PM) and regulated emissions from renewable rapeseed oil methyl ester (RME) biodiesel in pure and blended forms and contrasts that to conventional diesel fuel. Environmental and health concerns are the major motivation for combustion engines research, especially finding sustainable alternatives to fossil fuels and reducing diesel PM emissions. Fatty acid methyl esters (FAME), including RME, are renewable fuels commonly used from low level blends with diesel to full substitution. They strongly reduce the net carbon dioxide emissions. It is largely unknown how the emissions and characteristics of PM get altered by the combined effect of adding biodiesel to diesel and implementing modern engine concepts that reduce nitrogen oxides (NOx) emissions by exhaust gas recirculation (EGR). Therefore, the exhaust from a single-cylinder Scania D13 heavy-duty (HD) diesel engine fuelled with petroleum-based MK1 diesel, RME, and a 20% RME blend (B20), was sampled while the inlet oxygen concentration was stepped from ambient to very low by varying EGR. Regulated gaseous emissions, mass of total black carbon (BC) and organic aerosol (OA), particle size distributions and the soot nanostructure by means of transmission electron microscopy (TEM), were studied. For all EGR levels, RME showed reduced BC emissions (factor 2 for low and 3-4 for higher EGR) and total particulate number count (TPNC) compared with diesel and B20. B20 was closer to diesel than RME in emission levels. RME opens a significant possibility to utilise higher levels of EGR and stay in the region of low NOx, while not producing more soot than with diesel and B20. Adding EGR to 15% inlet O2 did not affect the nanostructure of PM. A difference between the fuels was noticeable: branched agglomerates of diesel and RME were composed of many primary particles, whereas those of B20 were more often “melted” together (necking).
Novakovica, Maja, Shamun, Sam, Malmborg, Vilhelm B., Kling, Kirsten I., Kling, Jens, Vogel, Ulla B., Tunestal, Per, Pagels, Joakim, Tuner, Martin
Fuel Cell Vehicles: An Opportunity for China's Greenhouse Gas Reduction2019-01-226312/19/2019
Fuel cell vehicle and battery electric vehicle are two environmentally benign vehicle technology types possibly meeting the zero-emission regulations in the future. The premise is they can achieve parity with conventional vehicle both environmentally and economically. Besides, it is necessary to distinguish which technology is more suitable in China's current and future context. This paper compares their cost-effectiveness for reducing greenhouse gas emissions, examining the life-cycle greenhouse gas emissions of conventional gasoline vehicle, battery electric vehicle and fuel cell vehicle in China's energy context under three different scenarios. The results indicate that under the 500km drive range, fuel cell vehicles are less competitive than battery electric vehicles currently. Fuel cell vehicles generate much more greenhouse gas emissions than battery vehicles and conventional gasoline vehicles. While with the optimization of energy context, fuel cell vehicles can gain competitiveness with battery electric vehicles in terms of greenhouse gas emissions, and with mass production as well as fuel cell system cost reduction, fuel cell vehicles can realize a better cost-effectiveness. Based on this analysis, it is recommended that the energy context should be optimized before deploying the fuel cell vehicles on a large scale in China. Technology enhancement both in hydrogen production and fuel cell, as well as manufacture optimization for fuel cell systems are equally essential in improving its cost-effectiveness.
Mu, Zhexuan, Hao, Han, Liu, Zongwei, Zhao, Fuquan
Study on Engine Start Vibration Index in a Hybrid Powertrain Using Torque Sensor and Cylinder Pressure Sensor2019-01-503411/4/2019
This paper presents an investigation of drivability issue of engine start-stop. Hybrid vehicles provide excellent benefits regarding fuel efficiency and emission. However, vibration results from constant engine start and stop events generate drivability issues, thus compromising driving comfort. This paper has designed a high speed torque sensor to capture instantaneous torque at the engine shaft. Its consequences help to find out the most suitable index of vibration severity. This paper is organized in four sections. The first section introduces the powertrain to be studied. The second section introduces development of a specially designed torque sensor. The torque sensor is installed between the engine and ISG (Integrated Starter Generator), alongside with an encoder. The torque sensor is utilized to collect the instantaneous shaft torque on occasion of engine start. In the third section, this paper has performed two experiments. Firstly, a typical engine start process (from 0 to 650 rpm) is studied. Instantaneous shaft torque, encoder signal and cylinder pressure signals are gathered and synchronized. Cranking phase and initial combustion phase is observed. It is concluded that torque generated from cylinder pumping air is the main contributor to the engine torque ripple, which is the main cause of vibration. Use that, three vibration index candidates are bought out, and square of angular acceleration is chosen. Then, this paper performed another experiment with an engine working at 1000 rpm and 100 Nm to examine the performance of vibration index. The results show the effectiveness of vibration index.
Yang, Fuyuan, Du, Lei, Hu, Yaodong
Analysis of the Impact of the WLTP Procedure on CO 2 Emissions of Passenger Cars2019-24-024010/7/2019
Until 2017 in Europe the Type Approval (TA) procedure for light duty vehicles for the determination of pollutant emissions and fuel consumption was based on the New European Driving Cycle (NEDC), a test cycle performed on a chassis dynamometer. However several studies highlighted significant discrepancies in terms of CO2 emissions between the TA test and the real world, due to the limited representativeness of the test procedure. Therefore, the European authorities decided to introduce a new, up-to date, test procedure capable to closer represent real world driving conditions, called Worldwide Harmonized Light Vehicles Test Procedure (WLTP). This work aims to analyze the effects of the new WLTP on vehicle CO2 emissions through both experimental and simulation investigations on two different Euro 5 vehicles, a petrol and a diesel car, representatives of average European passenger cars. The study also considers the effect of the engine warm-up and the impact of the start-stop technology in this new TA scenario. Since the WLTP imposes higher test mass and Road Loads (RLs), as well as higher driving cycle dynamics, a 44% cycle energy demand increase for the petrol car and a 23% increase for the diesel car were found. However, CO2 emissions increased in the same proportion only for the diesel car, while they increased only by 10% for the petrol car, thanks to the improvement of the average internal combustion engine efficiency along the WLTC cycle. Finally, the effectiveness of the start-stop in terms of fuel (or CO2) savings, was found to be almost halved for both vehicles when passing from the NEDC to the WLTP.
DiPierro, Giuseppe, Millo, Federico, Cubito, Claudio, Ciuffo, Biagio, Fontaras, Georgios
Development of a Low Friction High Performance Wheel Bearing Seal2019-01-21359/15/2019
The ever tightening of fuel economy and greenhouse gas emissions standards globally continues to challenge bearing companies toward lower torque, lower mass products. This paper focuses on improving fuel efficiency by considering the torque of automotive wheel bearing seals. This study establishes the level of drag torque reduction achieved through the structural design of the bearing seals. Wheel bearing seals are a critical component that must pass stringent torque, water exclusion, and other critical OEM and supplier performance specifications. They are designed as non-serviceable and must maintain full performance through the life of the vehicle. As a result of the application of specialized structural design, the drag torque, per the study, is reduced by more than 50% compared to existing bearing specifications. Electric vehicle companies are also seeking low friction wheel bearing solutions to further reduce CO2 (indirect or wheel-to-wheel) emissions. This research findings can assist the OEM’s in meeting the rigid emissions and fuel economy standards through drag reduction in the wheel bearings.
Kim, Yongwon, Cha, Chae Yeong, Jin, Seonggyu, Mahr, Reinhold, Lee, Seungpyo
Diesel Vehicle with Ultra-Low NOx Emissions on the Road2019-24-01459/9/2019
The gap between diesel vehicle emissions in laboratory tests compared to those in use has been addressed by the introduction of the Real Driving Emissions (RDE) requirements. Modern diesel technology now demonstrates low emissions on the road over a wide range of driving conditions. This paper further demonstrates that consistent low nitrogen oxide (NOx) and particle number (PN) emissions can be achieved over a wide range of driving conditions beyond Euro 6d RDE requirements, with emission control technologies combined in an integrated approach. An LNT (Lean NOx Trap) is combined with a dual-dosing SCR (Selective Catalytic Reduction) system. Low-load NOx control is achieved by the LNT in combination with a close-coupled SCR coated on the Diesel Particulate Filter (SDPF). High load conditions, on the other hand, are covered by the underfloor SCR system with a second AdBlue® injector. A P0 48V mild-hybrid system is also available to support the NOx control and to ensure good driving performance and fuel efficiency. An advanced control strategy is implemented to ensure optimal interaction between all emission control functionalities. The system was implemented on a C-segment demonstrator vehicle. The paper discusses the emissions tests performed and the results achieved. A combination of tests on the road and in the lab were carried out to cover a wide range of driving conditions. Special attention was paid to the robustness of the emission performance under urban and motorway driving conditions. Results demonstrate that each aftertreatment component contributes to achieving consistently low NOx emissions under all driving conditions. Particulate emissions are effectively controlled by the DPF.
Demuynck, Joachim, Favre, Cecile, Bosteels, Dirk, Bunar, Frank, Spitta, Joachim, Kuhrt, Andreas
Impact of Ethanol and Aromatic Hydrocarbons on Particulate Emissions from a Gasoline Vehicle2019-24-01609/9/2019
The impact of transport on global and local pollution has resulted in stricter emission limits. More specifically, increasing attention is being paid to exhaust gas particulate emissions in spark ignition engines. The particulate formation is mainly affected by: 1-engine and fuel system characteristics, 2-fuel properties and 3-exhaust aftertreatment system. In order to estimate the influence of fuel characteristics on particulate emissions, several research works have proposed fuel indices that correlate some of the fuel physical and chemical properties with engine particulate emissions. This work investigates the impact of fuel composition on particulate emissions and evaluates the Honda Particulate Matter Index (PMI) proposed by Aikawa et al. and other fuel indices in terms of agreement with vehicle test bed results for a passenger car. Vehicle tests were performed on New European Driving Cycle (NEDC) and Worldwide Harmonized Light Vehicles Test Cycle (WLTC) by using an E10 Euro VI reference fuel and five different fuel blends with 10% to 20% of ethanol and 23% to 35% of aromatic hydrocarbons content by volume. The effect of aromatic hydrocarbons composition on particulate emissions is also investigated by considering the same amount of global aromatic hydrocarbons but different aromatic composition: heavy aromatic hydrocarbons (C11)- and light aromatic hydrocarbons (C7-C9). Results illustrate a good correlation between particulate emissions and aromatic hydrocarbons content but little or no sensitivity of particulate emissions to ethanol content in the fuels. The comparison of the fuel particulate indices and vehicle results revealed different sensitivities but good overall agreement. It was also found that particulate emissions present a high sensitivity to heavy aromatic hydrocarbons content. These results highlight the importance of fuel quality and more specifically the role of heavy aromatic hydrocarbons on particulate emissions.
Tahtouh, Toni, Ben Amara, Arij, Anselmi, Patricia, Starck, Laurie
Experimental Investigations on Engine-Out Emissions Sensitivity to Fuel Injection Pressure of a High-Performance DISI Single Cylinder Engine2019-24-01699/9/2019
In recent times, complying with increasingly stringent emission regulations has become ever more challenging than before. While an efficient after-treatment system, that includes a gasoline particulate filter, enables compliance with legislation requirements, lowering engine-out emissions by improving the combustion system must be considered as a crucial advantage for both pollutants emission control and performance. In this respect, high-performance enabling contents such as relatively large displacement, flow-capacity oriented intake ports and a limited stroke-to-bore ratio have significant drawbacks on the charge motion quality and, consequently, on mixture formation and homogeneity. As a countermeasure, fuel injection system components, as well as control strategies, need to be substantially improved. The increase of fuel injection pressure, coupled with optimized injection timing and splitting, has proven to be effective in reducing emissions, especially with regard to particulate matter. This paper provides results of an experimental study investigating the effect of different fuel injection strategies on engine-out emissions, with special emphasis on the influence of very high fuel injection pressures (up to 50 MPa) on particulate matter. A multi-hole inwardly-opening fuel injector fitted to a high specific power direct-injection spark ignition (DISI) single cylinder engine, was tested over a wide range of steady state operating conditions, including catalyst heating, part loads and rated power. A fast particle spectrometer was employed along with a PMP-compliant particle counter to fully characterize fuel injection pressure effect on particle number and size distribution. The results show that significant improvements can be achieved over the entire range of investigated engine operating conditions, especially in regard to particulate matter emissions.
Rossi, Vincenzo, Silvestri, Nicola, Medda, Massimo
Exploring the Potential of Miller Cycle with and without EGR for Maximum Efficiency and Minimum Exhaust Emissions in a Heavy-Duty Diesel Engine03-12-05-00379/3/2019
Abstract In order to improve the fuel conversion efficiency and meet more stringent exhaust emissions regulations, Miller cycle and exhaust gas recirculation (EGR) have been researched as separate means to reduce carbon dioxide (CO2) and pollutant emissions from the internal combustion engines. In this article, an experimental work was carried out to explore the potential benefits of Miller cycle operation via late intake valve closing (LIVC) with and without EGR in a single-cylinder heavy-duty (HD) diesel engine equipped with a variable valve actuation (VVA) system. The overall engine-out emissions, fuel conversion efficiency, and estimated urea consumption in the selective catalytic reduction (SCR) aftertreatment were analysed and compared over the World Harmonized Stationary Cycle (WHSC) for different combustion control strategies. Additionally, the potential of Miller cycle with and without EGR based on the “SCR-only” and “SCR + EGR” technical routes to meet the Euro VI nitrogen oxides (NOx) limit of 0.4 g/kWh was assessed at different NOx aftertreatment efficiencies. When considering the urea consumption in the SCR, the results showed that the introduction of EGR allowed for an engine operation with higher corrected net indicated efficiency (NIEcorr.) or lower specific total fluid consumption than the baseline cases without EGR due to the relatively lower engine-out NOx emissions. However, the use of EGR adversely affected soot and carbon monoxide (CO) emissions when operating with constant intake pressure (Pint) of the baseline case. The application of Miller cycle with and without EGR strategies decreased the NIE and NIEcorr. when operating with the same Pint of the baseline operation. The use of higher Pint helped to improve upon the NIE and NIEcorr. of the Miller cycle cases. The WHSC cycle-averaged analysis showed that different combustion and engine control technologies can be adopted with and without EGR to meet Euro VI NOx limit. A conventional baseline engine operation without EGR would require a high SCR efficiency of 96% in order to curb a cycle-averaged NOx emissions level of 10 g/kWh. Miller cycle operation without EGR achieved the optimum NIEcorr. at the cycle-averaged NOx level of 8 g/kWh. When increasing the Pint, this strategy enabled an increase of 2.6% in the NIEcorr. and reduced the required SCR efficiency to 93.5%, but with a penalty on the NIE of 3.3% when controlling the cycle-averaged NOx level at 6.5 g/kWh. Alternatively, Miller cycle operation with EGR and higher Pint allowed for cycle-averaged NOx levels of 4.0 g/kWh, decreased the total fluid consumption by 8%, and minimised the required SCR efficiency to 90%. Therefore, this study has presented promising cost-effective emission control and fuel efficiency technologies that could be suitable for the “SCR-only” and “SCR + EGR” technical routes for the future HD diesel engines.
Guan, Wei, Pedrozo, Vinícius B., Wang, Xinyan, Zhao, Hua, Ban, Zhibo, Lin, Tiejian
A Study on NVH Performance Improvement of TPE Air Intake Hose Based on Optimization of Design and Material2019-01-14916/5/2019
Environmental and fuel economy regulations (Eu 6d and WLTP RDE) on automobiles have been tightened recently. To counter this regulation, the global automobile industry is focusing on weight reduction, fuel efficient turbo charger, cooled EGR, thermal management, low friction and so on. However, the high-speed turbocharger makes turbulence, and resulting in airflow noise. This noise is transmitted indoor through the air intake system, which adversely affects the vehicle's competitiveness. Therefore, for turbo engine, it is essential to reduce the noise of the air intake system. The air intake system consists of air cleaner, air filter, air intake hose and air duct. The air flow noise of turbo-engine is mainly the emission noise emitted from the walls of air intake system. And the transfer path of turbo noise is in order of air intake hose, air cleaner and air duct. Therefore, it is effective to reduce the noise of the air intake hose located at the beginning of noise transfer path. In the past, rubber hoses with vibration and acoustic insulation were mainly used to reduce the emission noise of air intake hose, but these can’t be recyclable and have high density (heavy). To overcome these shortcomings, TPE hoses are being applied, which are lighter, more competitive, durable and recyclable than rubber hoses. However, the air intake hoses with thin bellows and rigid TPE material have less noise attenuation performance than rubber hoses, so need to be improved noise insulation performance. This paper describes how to improve the NVH performance by optimizing the bellows design of air intake hose related to mass (m) and stiffness (k) and developing high damping material (c).
Jung, Hyunsoo, Jin, Jungkook, Park, Jong Min, Jin, Yong Sun (Steven), Han, Won Hee, Kim, Younghae, Gu, Yu
Cleaner Trucks Initiative starts NOx-reduction journey19TOFHP06_126/1/2019
The U.S. Environmental Protection Agency (EPA) is in the beginning stages of establishing new NOx regulations for heavy-duty on-highway trucks. The agency is spurred by advances in technology and a desire to streamline the certification process. The EPA last revised NOx standards for on-road heavy-duty trucks and buses in January 2001. The process that culminated in those standards actually started in the late 1990s. Rulemaking takes time, both to understand technology trends and incorporate a wide group of stakeholders. It will take no less time to update those NOx standards under the program called the Cleaner Trucks Initiative (CTI), announced by the EPA in November 2018.
Morey, Bruce
EDITORIAL: Choking on the haze of California vs. the Feds19AUTP05_075/1/2019
The term “smog” had not yet been coined when, on July 26, 1943, the first atmospheric inversion blanketed Los Angeles. This alarming, eye-watering and lung-busting cloud-pollution so extreme that some Angelenos thought it was a wartime gas attack-was a harbinger for the deteriorating air quality to come. The situation eventually led California to create its pioneering Motor Vehicle Pollution Control Board. By the mid-1960s, California had established the first U.S. vehicle emissions standards-which the federal government adopted for 1968-model cars. This pattern-the feds co-opting California's successful innovations-became the model for setting vehicle tailpipe and evaporative emissions standards in the U.S., amid stiff pushback from automakers.
Brooke, Lindsay
Development and Experimental Validation of a Control Oriented Model of a Catalytic DPF2019-01-09854/2/2019
1 The wall-flow Diesel Particulate Filter (DPF) is currently the most common after-treatment system used to meet the particulate emissions regulations for automotive engines. Today’s technology shows the best balance between filtration efficiency and back-pressure in the engine exhaust pipe. During the accumulation phase the pressure drop across the filter increases, thus requiring periodic regeneration of the DPF through after and post fuel injection strategies. This paper deals with the development of a control oriented model of a catalytic silicon carbide (SiC) wall flow DPFs with CuFe2O4 loading for automotive Diesel engines. The model is intended to be used for the real-time management of the regeneration process, depending on back-pressure and thermal state. In order to ensure suitable computational demand and to realize emissions control and fuel economy objectives, the 0-D model has been developed with the aim of investigating the essential behavior of the system, such as the chemical kinetic of filtered soot oxidation, the thermal and backpressure dynamics along accumulation and regeneration processes. Parameters identification and model validation have been performed vs. experimental data measured on the engine test bench at the exhaust of a EURO 5 light-duty Diesel engine, in different operating conditions. During the accumulation process, engine speed, load and rail pressure are controlled to ensure several levels of trapped soot; on the other hand, the injections pattern, which directly affects the DPF inlet temperature, is handled during regeneration tests. The results show that the model simulates the thermal dynamics and the pressure drop across the filter with good accuracy.
D'Aniello, Federica, Rossomando, Bruno, Arsie, Ivan, Pianese, Cesare
Ultra-Low NOx Emission Prediction for Heavy Duty Diesel Applications Using a Map-Based Approach2019-01-09874/2/2019
As vehicle emissions regulations become increasingly stringent, there is a growing need to accurately model aftertreatment systems to aid in the development of ultra-low NOx vehicles. Common solutions to this problem include the development of complex chemical models or expansive neural networks. This paper aims to present the development process of a simpler Selective Catalytic Reduction (SCR) conversion efficiency Simulink model for the purposes of modeling tail pipe NOx emission levels based on various inputs, temperature shifts and SCR locations, arrangements and/or sizes in the system. The main objective is to utilize this model to predict tail pipe NOx emissions of the EPA Federal Test Procedures for heavy-duty vehicles. The model presented within is focused exclusively on heavy-duty application compression ignition engines and their corresponding aftertreatment setups. The accuracy of the model depends heavily on the ability to gain precise and repeatable test cell data to calculate an expansive SCR conversion efficiency map for the given aftertreatment system. This conversion efficiency map is verifiable based on expected/known chemical and physical properties of SCR aftertreatment systems. For this application, a 2-dimensional map was created, using SCR temperature and space velocity. The model requires several inputs including engine out NOx concentrations, SCR temperature, and exhaust flow/space velocity to input into the table and thus predict the corresponding tail pipe NOx. While different engine calibrations can impact the accuracy of the model, it was found that error in average tail pipe NOx prediction (g/bhp·hr) was approximately +/- 10%. For the purposes of this model, this error was found to be sufficient in providing the proper direction for ultra-low NOx aftertreatment development.
Singh, Navtej, Adelman, Brad, Malagari, Srinivasulu, Hickey, Kyle
Modeling of Close-Coupled SCR Concepts to Meet Future Cold Start Requirements for Heavy-Duty Engines2019-01-09844/2/2019
The low-NOx standard for heavy-duty trucks proposed by the California Air Resources Board will require rapid warm-up of the aftertreatment system (ATS). Several different aftertreatment architectures and technologies, all based on selective catalytic reduction (SCR), are being considered to meet this need. One of these architectures, the close-coupled SCR (ccSCR), was evaluated in this study using two different physics-based, 1D models; the simulations focused on the first 300 seconds of the cold-start Federal Test Procedure (FTP). The first model, describing a real, EuroVI-compliant engine equipped with series turbochargers, was used to evaluate a ccSCR located either i) immediately downstream of the low-pressure turbine, ii) in between the two turbines, or iii) in a by-pass around the high pressure turbine. These simulations indicate that the location downstream of the low-pressure turbine offers nearly the best NOx conversion, and that the optimal volume of the ccSCR in this location is 25% of a conventional SCR catalyst. The second model describes a conventional heavy-duty aftertreatment system, to which a ccSCR was added. This model was used to examine the performance of the ccSCR in the context of the full ATS. Optimization of the diesel oxidation catalyst (DOC) and SCR catalyst designs in this system was considered, as well as the use of an NH3 storage-based control strategy for DEF dosing to the SCR catalysts.
Harris, Thomas Miller, Mc Pherson, Kristoffer, Rezaei, Reza, Kovacs, David, Rauch, Hendrik, Huang, Yinyan
Review of Vehicle Engine Efficiency and Emissions2019-01-03144/2/2019
This review paper covers major regulatory and technology developments in 2018 pertinent to tailpipe emissions of greenhouse gases and criteria pollutants. Europe has proposed ambitious reductions in CO2 limits for both light- and heavy-duty sectors. The challenge is compounded with changing measurement norms and a significant shift away from fuel efficient diesels in the light-duty (LD) space. Both incremental and step changes are being made to advance internal combustion. New studies show that in-use NOx emissions from diesels can be much lower than required by the Euro 6 regulation. Discussions have already started on Euro 7 regulations, and the leading regulatory concepts and proposed technical solutions are provided. In the heavy-duty (HD) sector, the progress is outlined in improving engine and vehicle fuel efficiency through the US Department of Energy’s (DOE’s) SuperTruck II program and other representative studies. Common approaches among the participants include hybridization, waste heat recovery, and both open- and closed cycle incremental improvements. Emissions control focus is on evaluating pathways to achieve California’s contemplated low-NOx standards, recently also supported by the US EPA through the Cleaner Trucks Initiative. The challenge is to reduce cold start and low load emissions, requiring innovative engine and after-treatment system solutions. Leading concepts include close-coupled SCR (selective catalytic reduction), use of passive NOx adsorbers, integration of SCR (selective catalytic reduction) on DPFs (diesel particulate filters), low temperature urea or ammonia injection, dual SCR, and active and passive thermal management to raise exhaust temperatures. Work is also underway on a new low load certification cycle. Continued advancement is made on after-treatment components. Aged three-way catalysts (TWCs) and diesel oxidation catalysts (DOCs) are nearing 90% conversion at 150 °C. SCR catalysts continue to improve both their low temperature conversion as well as high temperature durability. Particulate regulations in Europe, China and India are leading to widespread adoption of gasoline particulate filters (GPFs). Lean burn gasoline engines can offer significant fuel economy benefits. NOx control is a challenge, and passive SCR systems and new catalysts are proposed.
Joshi, Ameya
A Generalized Component Efficiency and Input-Data Generation Model for Creating Fleet-Representative Vehicle Simulation Cases in VECTO2019-01-12804/2/2019
The Vehicle Energy Consumption calculation Tool (VECTO) is used for the official calculation and reporting of CO2 emissions of HDVs in Europe. It uses certified input data in the form of energy or torque loss maps of driveline components and engine fuel consumption maps. Such data are proprietary and are not disclosed. Any further analysis of the fleet performance and CO2 emissions evolution using VECTO would require generic inputs or reconstructing realistic component input data. The current study attempts to address this issue by developing a process that would create VECTO input files based as much as possible on publicly available data. The core of the process is a series of models that calculate the vehicle component efficiency maps and produce the necessary VECTO input data. The process was applied to generate vehicle input files for rigid trucks and tractor-trailers of HDV Classes 4, 5, 9 and 10. Subsequently, evaluating the accuracy of the process, the simulation results were compared with reference VECTO results supplied by various vehicle manufacturers. The results showed that the difference between simulated and reference CO2 emissions was on average -0.6% in the Long Haul cycle and 1% in the Regional Delivery. Such a process could be a powerful tool for calculating HDV CO2 emissions for development and analysis purposes, e.g. for new vehicle prototypes or multistage vehicles, and for creating VECTO equivalent models that can be used to assess alternative operating conditions and mission profiles of existing vehicle models. The methodology was applied for creating input of various components in the US tool for HDV certification, GEM, for generic sample-vehicle models available.
Zacharof, Nikiforos, Tansini, Alessandro, Prado Rujas, Iker, Grigoratos, Theodoros, Fontaras, Georgios
Fuel-to-Air Ratio Stimulation Suitability for Pollutant Emissions Reduction under Transient Driving Conditions2019-01-12914/2/2019
Fuel-to-air ratio stimulation, also called λ cycling or λ modulation, is a natural consequence of controlling fuel-to-air ratio in closed-loop with a switch-type λ-sensor. Nowadays, wideband λ-sensors are broadly extended and fuel-to-air ratio stimulation is an additional option that can or not be implemented in the control strategies to improve TWC conversion efficiency through the increase of the catalyst activity. The present work focus on the suitability of applying fuel-to-air ratio stimulation in a turbocharged GDI engine equipped with a close-coupled TWC. In particular, the influence of the main parameters such as stimulation amplitude and frequency on tailpipe emissions at steady-state conditions is assessed. The potential of λ cycling in order to reduce pollutant emissions in the face of fuel-to-air ratio disturbances has also been evaluated. Results show how a proper λ modulation decreases NOx emissions at lean conditions. However, at rich conditions CO emissions increases when fuel-to-air ratio stimulation is imposed.
Pla, Benjamin, Garcia-Cuevas, Luis Miguel, Guardiola, Carlos, Real, Marcelo
48V Mild-Hybrid Architecture Types, Fuels and Power Levels Needed to Achieve 75g CO2/km2019-01-03664/2/2019
48V mild hybrid powertrains are promising technologies for cost-effective compliance with future CO2 emissions standards. Current 48V powertrains with integrated belt starter generators (P0) with downsized engines achieve CO2 emissions of 95 g/km in the NEDC. However, to reach 75 g/km, it may be necessary to combine new 48V powertrain architectures with alternative fuels. Therefore, this paper compares CO2 emissions from different 48V powertrain architectures (P0, P1, P2, P3) with different electric power levels under various driving cycles (NEDC, WLTC, and RTS95). A numerical model of a compact class passenger car with a 48V powertrain was created and experimental fuel consumption maps for engines running on different fuels (gasoline, Diesel, E85, CNG) were used to simulate its CO2 emissions. The simulation results were analysed to determine why specific powertrain combinations were more efficient under certain driving conditions. As expected, the greatest influence on emissions was from powertrain architectures. Increased electric power levels (from 8 kW to 20 kW) allowed more brake energy to be recovered, reducing CO2 emissions by 2 - 16% depending on the driving cycle. The P2 and P3 architectures with even low electric motor power level offered substantially better fuel efficiency (by 19% on average) than a conventional powertrain with a start-stop system, whereas the P0/P1 architectures offered average improvements of only 4% for different power levels and driving cycles. In the P0 and P1 architectures, engine friction severely limited energy recovery during braking and made electric propulsion infeasible due to significantly increased power demands. The P2 and P3 architectures allow the engine to be decoupled from the powertrain and so avoid this problem. Overall, the 48V P2/P3 powertrains allowed for significant improvements in CO2 emissions when used with CNG, E85 or diesel fuel. 75 g/km target value was predicted to be achievable with CNG-fuelled systems under the NEDC and WLTC cycles, and possibly even under RTS95 on a well-to-wheel basis when using a renewable fuel such as E85.
Melaika, Mindaugas, Mamikoglu, Sarp, Dahlander, Petter
A Simulation Research on Emission Control Technology of Low-Speed Two-Stroke Diesel Engine Based on EGR and Miller Cycle2019-01-09454/2/2019
This paper investigates the influences of EGR and Miller cycle on NOx emission of a heavy-duty two-stroke diesel engine. The NOx emission is strictly restricted by the IMO Tier III Emission Regulations, resulting in an insufficient application of the single emission reduction technology to meet the emission requirements. It is asserted that EGR is the most effective manner to reduce NOx emission, but the fuel consumption increases simultaneously. In consideration of emission reduction with fuel economy, EGR and Miller cycle were combined and studied in this paper. Parameters like in-cylinder pressure, in-cylinder temperature, mass in the chamber, emission (NOx and soot) and fuel consumption rate were investigated based on a single-cylinder 3D model. The wet condition that happens in the engine application was considered in the model development process. The model was validated and compared with the experimental data. The simulation results show the "trade-off" relationship between NOx and soot under EGR, as well as the performance of reducing NOx in different load. This paper, subsequently, used Miller cycle (achieve by delay the closing timing of the exhaust valve with intake boosting) to optimize the fuel consumption rate base on the EGR results. Finally, the combustion conditions under different EGR ratio and different Miller cycle condition were reflected by in-cylinder pressure, the contours of in-cylinder temperatures and the generating area of NOx. According to the simulation results of EGR and Miller cycle, the optimum scheme was giving out to satisfy the IMO Tier Three with better fuel economy performance.
Zhu, Zhijie, Liang, Xingyu, Wang, Yuesen, Liu, Bo
Fuel and Engine Effects on Rich-Combustion Products as an Enabler of In-Cylinder Reforming2019-01-11444/2/2019
Onboard reforming has been proposed as a strategy for improving spark-ignited (SI) engine efficiency through knock reduction, dilution limit extension, improved thermodynamic gas properties, and thermochemical exhaust enthalpy recuperation. One approach to onboard fuel reforming is to combust fuel in the engine cylinder under rich conditions, producing a hydrogen-rich reformate gas--which can subsequently be recirculated into the engine. Hydrogen is the preferred product in this process due to its high flame speed and knock resistance, compared with other reformate constituents. In this work, the effects of engine operation, fuel composition and water injection were evaluated for their effect on reformate gas composition produced under rich combustion conditions. Engine parameters, including intake pressure, intake temperature, combustion phasing, and valve timing all had no significant impact on hydrogen yield at a given equivalence ratio. Fuel effects on hydrogen yield were more significant--with methanol producing 75% more hydrogen than toluene at the same equivalence ratio. The greater hydrogen yield was due to greater hydrogen content of the fuel, although the benefit was shown to be partially offset by lower hydrogen selectivity and conversion. Production of smoke limited the minimum relative air-fuel ratio of some fuels contributing to reduced hydrogen yields. Upstream water injection was shown to boost hydrogen production by 10-60% (rel.) at the expense of carbon monoxide due to steam reforming reactions and Le Chatlier’s principle in the water gas shift reaction. Toluene exhibited the greatest relative improvement in hydrogen yield due to the lower exhaust water concentrations in the absence of water injection. In the presence of water injection, hydrogen production in some cases exceeded fuel hydrogen content indicating the presence of water gas shift and steam reforming chemistry occurring. Using the speciated exhaust data, a correlation was developed using measured exhaust hydrogen content to predict hydrogen concentration from carbon monoxide and relative air-fuel ratio. The correlation developed improves upon previous correlations by explicitly including the hydrogen content of the fuel, and thus allowing more accurate prediction. Lastly, the energy balance was calculated under rich combustion conditions from the indicated power and chemical potential energy of the reformate. The energy balance analysis suggests that in-cylinder reforming is a net endothermic process, with some exhaust heat being converted into chemical potential energy. Overall, it was concluded that in-cylinder reforming can be used to produce practical quantities of reformate to improve SI engine performance. This work showed the potential for optimized fuels to improve in-cylinder reforming processes, in conjunction with water injection, to produce a hydrogen-rich reformate gas without parasitic losses.
Voice, Alexander K., Costanzo, Vincent
On Developing Advanced Catalysts Systems to Meet China New Regulations2019-01-09784/2/2019
Over the past few years, China has made major legislative advancements on vehicle emissions, having set forth Stage 6 regulations for both LD and HD vehicles. To meet stricter standards, OEMs and associated suppliers of the exhaust aftertreatment value chain have gone through a period of unprecedented development. This paper selectively describes key challenges and highlights corresponding solutions of those development for both segments. In doing so, the authors wish to provide an overview of the catalyst systems used in upcoming China automobile market. A key challenge for LDG Stage 6 is the introduction of FWCTM (Four-Way Catalysts, aka cGPF - Coated Gasoline Particulate Filter). This paper discusses advantages and disadvantages of different system solutions. Experimental study showed oxygen and temperature are critical factors to achieve effective soot regeneration in a FWCTM. Careful debugging and analysis are needed to identify causes in FWCTM system when tail-pipe emissions do not meet the PM and PN targets. The LDD segment is a niche market in China. It however has same level of technical complexity as in Europe when it comes to develop exhaust aftertreatment system to meet Stage 6. Technical trend and mainstream solution for China market are reviewed. The HDD Stage VI is very similar to EU VI regulation. Due to uneven market application and diesel fuel quality, OEMs tend to adopt the conventional DOC+CSF+Cu-SCR system and use proven catalyst technologies. This paper discusses those durability concerns and reviews dedicated experiments for design validation, especially on effect of prolonged thermal aging and high sulfur fuel. The off-road Stage IV standard has strong China attributes. Its gaseous emission limits are same as Europe Stage IIIB however it has a PN requirement not imposed until EU Stage V. This paper discusses possible off-road aftertreatment system pathways, with an emphasis on SCRoF for fit-for-market solution.
Tang, Weiyong, Siani, Attilio, Chen, Frank, Chen, Bob
Effects of Fuel Properties on Particle Number and Particle Mass Emissions from Lean and Stoichiometric Gasoline Direct Injection Engine Operation2019-01-11834/2/2019
Engine-out particle size distributions and soot mass emissions were measured from a gasoline direct injection (GDI) engine fueled by seven different gasoline formulations. Additionally, particle size distributions were simultaneously measured downstream of a catalyzed gasoline particulate filter (GPF) to determine the size resolved filtration efficiency. Stoichiometric, lean homogeneous, and lean stratified combustion modes were studied at four steady-state engine conditions. The particulate matter (PM) Index was calculated for each fuel as a function of the double bond equivalent and vapor pressure of the fuel components. There was generally poor correlation between particle number (PN)/PM mass emissions and the PM Index for steady state stoichiometric conditions with clean injectors, which emitted low particle concentrations. However, under high-load lean homogeneous conditions, there was good correlation between PN/PM mass emission and the PM Index, with the exception that the high ethanol content fuel produced significantly higher PM emissions than the other fuels. Under lean stratified conditions, most fuels produced similar particle size distributions and concentrations with the exception that the E50 fuel produced significantly lower concentrations than the other fuels. These results demonstrate the profound sensitivity of particle emissions from high ethanol content fuel to engine operating conditions. Additionally, these results show the predominant factor influencing particle formation is charge mixture formation, which fuel properties influence, but not as significantly as engine conditions. The GPF reduced the tailpipe particle number concentrations by 60 - 95% and showed evidence of passive regeneration under higher load lean engine conditions (Temp>400°C, Lambda>1.3). Total PN filtration efficiencies ranged from ~60 % with a clean filter to greater than 95% with as little as 25 mg/L of soot loaded on the filter with a most penetrating particle size (MPPS) between 100 and 150 nm. The GPF results show that GPF regeneration can be achieved with the added fuel efficiency benefit of lean operation.
Bock, Noah, Jeon, Joonho, Kittelson, David, Northrop, William
Development of an Alternative Predictive Model for Gasoline Vehicle Particulate Matter and Particulate Number2019-01-11844/2/2019
The Particulate Matter Index (PMI) is a helpful tool which provides an indication of a fuel’s sooting tendency. Currently, the index is being used by various laboratories and OEMs as a metric to understand the gasoline fuels impact on both sooting found on engine hardware and vehicle out emissions. This paper will explore a new method that could be used to give indication of the sooting tendency of the gasoline range fuels, called the Particulate Evaluation Index (PEI), and provide the detailed equation in its initial form. In addition, the PEI will be shown to have a good correlation agreement to PMI. The paper will then give a detailed explanation of the data used to develop it. Initial vehicle PM/PN data will also be presented that shows correlations of the indices to the vehicle response.
Chapman, Elana, Winston-Galant, Mark, Geng, Pat, Pryor, Sophia
ADVANCING aftertreatment19TOFHP04_034/1/2019
Engineers push for more efficient, cost-effective, and smaller aftertreatment systems for off-highway diesel engines, addressing challenges such as better particulate filtering and low-temp NOx conversion. Regulations in North America and Europe may have settled for the moment, but the pressure is still on for development in aftertreatment. “Emissions standards continue to expand beyond U.S. EPA and EU markets with countries such as China and India moving toward increasing air quality standards,” said James Schnuriger, Product Marketing for Perkins. “The need for aftertreatment systems continues to grow as emissions standards expand across the world.”
Morey, Bruce
Smart Engine Control Strategy for the Fuel Efficiency Improvement via Understanding the Unique Behavior of TWC2019-01-14063/25/2019
The worldwide fuel economy compliance level has been tightening, at the same time, LEV-III/Euro-6d/China-6/BS-6 regulations for NMOG and NOx emissions are being introduced or already effective. Therefore, intensive research effort has been conducted in order to improve the fuel efficiency of passenger cars and reduce exhaust emission. In response to these demands, turbocharged gasoline direct injection (TGDI) engine is being introduced for gasoline vehicles in consideration of fuel efficiency improvement, high output and driving performance compared to naturally aspirated (NA) engine. However, due to its larger thermal mass from the turbo hardware in the exhaust, it suffers from the cold-start emission. The main hazardous gases emitted from gasoline vehicles are CO, HC and NOx, and a three-way catalyst (TWC) is installed for the purification of these harmful emissions. But vehicle-mounted TWC converters gradually reduce the ability to purify hazardous emissions as vehicle mileage increases. Here, the degradation of TWC is caused by chemical poisoning and thermal sintering. The performance index of TWC is generally closely related to Oxygen Storage Capacity (OSC), and OSC also decreases as the TWC performance decreases. In this study, we investigated the change of tailpipe emissions according to the degradation of the TWC performance used in the 1.4 TGDI Elantra. For example, during transient conditions such as cold-start, fuel-cut, and O2 purge events, the tailpipe emission performance significantly depends on TWC properties such as the dispersion of active metals and OSC. Moreover, overall aftertreatment performance of TWC is determined by the exhaust composition (lambda) as well as its temperature controlled by the engine controls. We will propose smart engine control strategies to improve the fuel efficiency by understanding the relationship between the emission control performance and the properties of TWC.
Choung, Jin Woo, Lee, Soo Min, Kim, Sung Jae, Lee, Dong Hoon, Kwon, Kiyoung
EDITORIAL19AUTP02_052/1/2019
Brooke, Lindsay
Characterization of GDI PM during Vehicle Start-Stop Operation2019-01-00501/15/2019
As the fuel economy regulations increase in stringency, many manufacturers are implementing start-stop operation to enhance vehicle fuel economy. During start-stop operation, the engine shuts off when the vehicle is stationary for more than a few seconds. When the brake is released by the driver, the engine restarts. Depending on traffic conditions, start-stop operation can result in fuel savings from a few percent to close to 10%. Gasoline direct injection (GDI) engines are also increasingly available on light-duty vehicles. While GDI engines offer fuel economy advantages over port fuel injected (PFI) engines, they also tend to have higher PM emissions, particularly during start-up transients. Thus, there is interest in evaluating the effect of start-stop operation on PM emissions. In this study, a 2.5L GDI vehicle was operated over the FTP75 drive cycle. Runs containing cold starts (FTP-75 cycle Phases 1 & 2) and multiple runs containing hot starts (FTP-75 cycle Phases 3 & 4) were performed each day. Note that the FTP-75 Phases 3 & 4 are identical to Phases 1 & 2 except that the engine is warmed up. Three fuels were evaluated: an 87 AKI gasoline (E0), a 21% splash blend of ethanol and the 87 AKI gasoline (E21), and a 12% splash blend of iso-butanol and the 87 AKI gasoline (iBu12). PM mass, transient particle number concentration and size distribution, and soot mass concentration were evaluated for both start-stop operation and no start-stop operation on each fuel. Three Phase 1 & 2 cycles and as many as 27 Phase 3 & 4 cycles were performed for each fuel-mode combination. Composite FTP mass emissions for E0 and iBu12 showed increased total PM emissions with start-stop operation, but E21 showed no difference. Statistical analysis of the effects of start-stop on PM number and soot emissions showed different trends for different fuels. For example, when E0 is used with start-stop operation, the particle number decreased but the soot mass tended to increase. The results of this study have implications for hybrid vehicle operation as well because the internal combustion engine in hybrid vehicles must stop and re-start during normal operation.
Storey, John M., Moses-DeBusk, Melanie, Huff, Shean, Thomas, John, Eibl, Mary, Li, Faustine
Estimation of the Fuel Efficiency Potential of Six Gasoline Blendstocks Identified by the U.S. Department of Energy’s Co-Optimization of Fuels and Engines Program2019-01-00171/15/2019
Six blendstocks identified by the Co-Optimization of Fuels & Engines Program were used to prepare fuel blends using a fixed blendstock for oxygenate blending and a target RON of 97. The blendstocks included ethanol, n-propanol, isopropanol, isobutanol, diisobutylene, and a bioreformate surrogate. The blends were analyzed and used to establish interaction factors for a non-linear molar blending model that was used to predict RON and MON of volumetric blends of the blendstocks up to 35 vol%. Projections of efficiency increase, volumetric fuel economy increase, and tailpipe CO2 emissions decrease were produced using two different estimation techniques to evaluate the potential benefits of the blendstocks. Ethanol was projected to provide the greatest benefits in efficiency and tailpipe CO2 emissions, but at intermediate levels of volumetric fuel economy increase over a smaller range of blends than other blendstocks. A bioreformate surrogate blendstock was projected to provide the greatest increase in volumetric fuel economy and the lowest increase in efficiency. Tailpipe CO2 emissions for blends of the bioreformate surrogate were higher at all blend levels compared to the baseline E10 fuel.
Sluder, C. Scott
Water Injection Benefits in a 3-Cylinder Downsized SI-Engine2019-01-00341/15/2019
With progressing electrification of automotive powertrains and demands to meet increasingly stringent emission regulations, a combination of an electric motor and downsized turbocharged spark-ignited engine has been recognized as a viable solution. The SI engine must be optimized, and preferentially downsized, to reduce tailpipe CO2 and other emissions. However, drives to increase BMEP (Brake Mean Effective Pressure) and compression ratio/thermal efficiency increase propensities of knocking (auto-ignition of residual unburnt charge before the propagating flame reaches it) in downsized engines. Currently, knock is mitigated by retarding the ignition timing, but this has several limitations. Another option identified in the last decade (following trials of similar technology in aircraft combustion engines) is water injection, which suppresses knocking largely by reducing local in-cylinder mixture temperatures due to its latent heat of vaporization. Addition of adequate water can lead to stoichiometric air/fuel ratio engine operation, and hence both reduction in fuel consumption and full utilization of a three-way catalytic converter (TWC). Further information about effects of various water injection parameters is required. Thus, in this study, a 4-stroke, 1.5 liter, 3-cylinder turbocharged engine with direct fuel injection and port water injection was operated on 91, 95 and 98 RON gasoline fuel to assess effects of water injection on knock mitigation, combustion phasing, required air:fuel ratios and exhaust gas temperature control. Full- and part-load curves obtained with different fuels and water injection strategies are presented and discussed.
Khatri, Jayesh, Denbratt, Ingemar, Dahlander, Petter, Koopmans, Lucien
An Experimental Study of the Effects of Coolant Temperature on Particle Emissions from a Dual Injection Gasoline Engine2019-01-00511/15/2019
Euro VI emission standards have set a very strict limitation on particulate matter emissions of Gasoline Direct Injection (GDI) engine. It is difficult for GDI engine to meet the Euro VI PN regulation (6×1011#/km) without a series of complicated after-treatment devices such as Gasoline Particulate Filter (GPF). Previous research shows that GDI vehicles under cold start condition account for more than 50% of both particle number and mass emissions during the entire NEDC driving cycle. Dual Injection Gasoline engine is based on the GDI engine by adding a set of port fuel injection system. The good mixing characteristics of the port fuel injection system can help to reduce the particulate matter emissions of the GDI engine during the cold start condition. In this study, a Cambustion DMS500 fast particle spectrometer was employed to characterize the effects of coolant temperature and direct injection ratio on particulate emissions from a turbocharged four-cylinder dual-injection gasoline engine. The experimental results showed that with the coolant temperature increasing the particulate matter tended to be consistent under the port fuel injection mode. The particulate matter showed significantly drop with the coolant temperature increasing both in the dual injection mode and the direct injection mode. At the same coolant temperature, with the decrease of the direct injection ratio, the particulate matter showed notably reductions, and with the increase of coolant temperature, the magnitude of the reductions gradually declined. The experimental results provided important guidance to reduce the particulate matter via dual injection mode during the cold start condition.
Xia, Chun, Chen, Wenhao, Fang, Junhua, Huang, Zhen
Impact of Secondary Air Injection on Small Engine Motorcycle Intended for BS VI Applications2018-32-006810/30/2018
On April 2020, India will move from Bharat Stage IV to Bharat Stage VI where the combined emission limit of Total Hydrocarbons (THC) and Nitrogen oxides (NOx) of 0.79g/km will independently reduce to 0.1g/km and 0.06g/km respectively. This reduction in emission limit however may prove to be challenging for small engines (below 200 cc) with the existing generation of engines predominantly in cold operating conditions. When the vehicle is started after soaking (engine turned off for few hours), considerable amount of THC emission is generated which can be attributed to poor fuel vaporization and incomplete combustion due to flame quenching in the combustion chamber. Also, the catalyst is inactive to chemical reactions until the accumulated heat energy from the hot exhaust mass flow elevates the catalyst temperature to facilitate efficient conversion of THC, CO and NOx to H2O, CO2 and N2. This temperature point is termed as catalyst light off temperature. Hence, most of the tail pipe emissions vented out to the atmosphere in cold phase is without after-treatment. In case of two wheelers on a typical drive cycle, around 60% (fig. 3) of the total tail pipe THC emitted is before the catalyst attains light off temperature. Thus, any form of exhaust gas treatment that can lead to reduction of pre-catalyst emissions and faster catalyst light off, will prove to be beneficial in overall emission reduction. In this context, Secondary Air injection (SAI) is explored as an effective exhaust treatment method in tackling cold phase emissions. In the present study, a series of tests were conducted on a single cylinder 200cc engine fitted with a Mechanical throttle body and electronic fuel injection system. From these tests, various aspects of cold phase emissions were characterized. This paper explores in detail the impact of SAI on pre-catalytic oxidation of THC, catalyst temperatures and catalytic reactions. Present study also gives an insight into the operation of SAI such that it does not compromise the functionality of the three way catalyst (TWC). It was also observed that it is beneficial to have different modes of SAI operation such as open loop mode without oxygen sensor feedback, closed loop mode with oxygen sensor feedback and engine load specific operation of SAI. Upon application of best optimal configuration of SAI a reduction of 25% in THC and 4% of NOx was observed.
Sabu, Abhijith, Reddemreddy, Pramod, Parmar, Manojkumar
Preparing BMW Motorrad’s Boxer Engine for the Future: Improving Performance, Driveability and Efficiency While Fulfilling Future Emission Standards2018-32-008310/30/2018
Engine development mostly revolves around the same competing goals. With the implementation of the EU4 and EU5 emission standards for motorcycles, the difficulty of increasing performance and improving driveability and efficiency, while simultaneously fulfilling the Emission standards becomes even higher. Though the automotive industry offers a variety of solutions for the named topics, their implementation in a high performance motorcycle engine with specific needs regarding packaging, a wide operating range and full load behavior, represents a special challenge. This paper presents the approach of BMW Motorrad to meet these goals on the example of the boxer engine, focusing on the methodology throughout the development process. The gas exchange system of the engine was optimized using 1D gas dynamic simulations and 3D CFD analysis for a redesign of the valve train, ports and valves. The results of the calculations were further confirmed by experiments at the flow test bench measuring discharge coefficients and using particle image velocimetry (PIV). Combined simulation and engine testing led to a newly developed exhaust manifold enabling a faster light-off and a more stable operating temperature of the catalyst, while reducing raw exhaust emissions through a new injector layout. Engine experiments showed lower emissions, an improved efficiency and a more stable combustion in part load as well as an increased performance at full load. These results translated into lower exhaust emissions and fuel consumption when testing the motorcycle in the world motorcycle harmonized test cycle (WMTC).
Oppelt, Maximilian, Schwarz, Frank, Eibl, Rüdiger, Gaitan, Pedro
Technologies to Achieve Future Emission Legislations with Two Stroke Motorcycles2018-32-004210/30/2018
Increasingly stringent emission regulations force manufacturers of two wheelers to develop low emission motorcycle concepts. Especially for small two-stroke engines with symmetrical port timing structure, causing high HC-emissions due to scavenge losses, this is a challenging demand that can only be met with alternative mixture formation strategies and by intensifying the use of modern development tools. Changing from EU4 to EU5, emission legislation will not only have an impact on the improvement of internal combustion but will also drastically change the after-treatment system. Nowadays, small two-stroke engines make use of a simple carburetor for external mixture preparation. The cylinders are scavenged by air/fuel mixtures. Equipped with exhaust gas after-treatment systems, such as secondary air with two or three catalytic converters, the emission limits for EURO 4 homologation can be achieved with carbureted engines. An increased number of catalytic converters in the exhaust system reduces the performance of a carbureted two stroke engine and has therewith no advantage in comparison to a four stroke engine. Electronically controlled direct injection systems with low pressure (SETC 2008-32-0059), reducing the untreated emissions by minimizing the typical scavenge losses can also be found in this market segment. Approaches to reduce the exhaust emissions with high pressure direct injection systems have been investigated in 50cm3 two-stroke applications, but they are not present as mass products on the market yet. Due to the advantage of a direct injection system, a simple oxidation catalyst, the same as in EURO 2 engines, can fulfill the EURO 4 emission standard without any performance losses. But only focusing on injection technology, it is not possible to achieve the next legislation step with two stroke engines. There are two main characteristic limits. First, a drastic reduction of cold start HC emission is necessary and second, a lambda = 1 application is forced to fulfill the EU5 emission limit in terms of NOx. A novel approach to achieve low emissions in this engine category is the main subject of this publication. By analyzing different strategies and technologies done with two stroke vehicles on the roller dynamometer, an estimation in terms of performance, exhaust emissions and costs will show a possible way to reach EU 5 emission stage. As the biggest disadvantage of two stroke engines is still the high level of scavenge losses, especially at cold start, the time of the respective effect of the different solutions is of great importance. Additionally, a combination of solutions for a 50cc Scooter shows the potential to fulfill the future emission targets.
Oswald, Roland, Kirchberger, Roland, Krimplstatter, Stefan
System Identification Method for Brake Particle Emission Measurements of Passenger Car Disc Brakes on a Dynamometer2018-01-188410/5/2018
Besides particulate emissions from engine exhausts, which are already regulated by emission standards, passenger car disc brakes are a source of particulate matter. With the current car fleet it is estimated that up to 21% of the total traffic related PM10 emissions in urban environments originate from brake wear and reduction of brake dust emissions is subject of current research. For the purpose of reducing brake dust emissions by choosing low-emission operating points of the disc brake, the knowledge of the emission behavior depending on brake pressure, wheel speed, temperature and friction history is of interest. According to the current state of research, theoretical white box modeling of the emission behavior is complicated due to the complexity of tribological contact between pad and disc. Thus experimental black box modeling is supposed to describe emission behavior. In order to minimize the influence of disturbances and therefore to improve prediction accuracy of such empirical models, system identification methods based on periodical test signals, such as brake pressure sine, are used for this application. To adopt these test signals, which are established in transfer function measurements, to the application of brake particle measurements and to develop an experimental design, system theoretical quantities, such as cutoff frequency, signal to noise ratio and hysteresis, are determined in dynamometer tests. Therefore measurements of the system’s response to step and sine test signals are analyzed. System identification is executed and the applicability of periodical test signals to brake particle measurements is proven.
Niemann, Hartmut, Winner, Hermann, Asbach, Christof, Kaminski, Heinz, Zessinger, Marco
Emissions reductions continue to disrupt CV industry18TOFHP10_0510/1/2018
As the automotive and commercial vehicle (CV) industries expand from being dominated by a single powertrain to a multitude of power and fuel options, disruption is propelling change to the entire mobility ecosystem. The emissions field continues to see this change as regulations further reduce output levels on a global scale. The California Air Resources Board (CARB) remains a leading organization of reducing emission levels in the U.S. Based on the Environmental Protection Agency's (EPA) reports of excessive ozone levels in the state, CARB is seeking to reduce NOx output by 80%. As further recognition of this issue, the Governor of California recently signed Senate Bill 100 to make the state's energy production 60% renewable by 2030 and 100% renewable by 2045.
Borst, Matthew
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