Browse Topic: Boost pressure

Items (1,827)

Regulated Intake Air Boosting and Engine Downspeeding as a Viable Solution for Performance Improvement and Emission Reduction of a Single-Cylinder Diesel Engine

03-15-02-0009

8/16/2021

The present work proposes a viable approach to develop single-cylinder diesel engines for the future by implementing regulated intake air boosting (RIAB) and engine downspeeding (ED) along with the well-established low compression ratio (LCR) approach. The investigations were conducted in a mass-production light-duty single-cylinder diesel engine initially equipped with a naturally aspirated (NA) intake system. By lowering the compression ratio (CR) and implementing the intake air boosting (IAB) using a belt-driven supercharger, the maximum brake mean effective pressure (BMEP) of the engine could be increased by 50%. More importantly, the improved performance could be achieved without violating the peak firing pressure (PFP) limits. However, a significant penalty was observed in the brake-specific fuel consumption (BSFC) at low-load operating points due to the additional power consumption of the IAB system. Hence, RIAB was implemented to optimize the boost pressure with respect to engine load to simultaneously reduce the BSFC and oxides of nitrogen (NOx) and soot emissions. Further, the increased full-load performance of the engine was leveraged to implement the ED approach that could reduce the operating speeds of the engine by 37.8%. It was observed that the benefits of downspeeding a supercharged engine are significantly high due to the simultaneous reduction of the frictional losses of the base engine and the power consumption of the supercharger. Overall, by combining the above concepts and the proven LCR approach, significant benefits could be achieved in fuel economy and exhaust emissions that are quantified for the regulatory Modified Indian Drive Cycle (MIDC) using a one-dimensional tool. The obtained results show a net reduction of 77.8% and 39.5% in the soot and NOx emissions, respectively. Moreover, a significant benefit of 14.8% could be achieved in the fuel economy. Thus the proposed approach can be used to develop single-cylinder diesel engines for the future to improve vehicle performance and comply with stringent emission regulations.

Vikraman, V., Krishnasamy, Anand, Ramesh, A.

Power and Torque Determination for UAS Engines Having Maximum Power Ratings at or Below 22.4 kW

ARP6971 (Current)

4/7/2021

This recommended practice is applicable to reciprocating engines powering unmanned aerial vehicles (UAV) having rated power values less than 22.4 kW, and which are not to be used for human transport.

E-39 Unmanned Aircraft Propulsion Committee

7.0.101 - A New Image De-hazing Method for Safety Critical ADAS Applications

SAE-PP-002772/4/2021

Driver safety and Advanced Driver Assistance Systems (ADAS) is gaining lot of importance these days. In some countries, there are strict regulations in place which mandate the use of certain ADAS features in automobiles. However, as the need for these safety critical systems increases, the challenges associated also increase. These challenges can arise due to technology, human factors or due to nature. In countries like India, where one can expect different weather conditions with changing geography, the associated challenges are mainly due to the natural factors like haze, fog, rain and smoke. This poses a challenging problem in terms of visibility for the drivers as well as in vision based ADAS; thereby, leading to many fatal road accidents. In this paper, a novel pre-processing technique, which addresses the interesting problem of enhancing the perceptual visibility of an image that is degraded by atmospheric haze, is proposed. The solution to this problem is presented by combining model (Beer Lambert model) based and non-model based technique of haze removal. The combined hybrid model picks the best haze free image from the series of non-hazy outputs, that are derived based on multiple scattering coefficients of the input hazy image. The idea here is to restore the true color of an image that is affected by the atmospheric haze. In comparison with the state of the art methods that are available in literature, the proposed method is shown to be capable of recovering better haze-free images both in terms of visual perception and quantitative evaluation. The proposed method promises better perceptual understandings and visibility restoration for vision based ADAS under hazy driving conditions.

Lname, Fname

6.0.116 - Development of 6 Years Old Child Virtual Model by Automatic Scaling

SAE-PP-002712/4/2021

Traffic accidents cause one of the highest numbers of severe injuries in the whole population. The numbers of deaths or seriously injured citizens prove that traffic accidents and their consequences are still a serious problem to be solved. A lot of effort is devoted to both passive and active safety systems development. The transportation standards usually define safety requirements by regulations (e.g. ECE-R94, 96/79/EC and ECE-R95, 96/27/EC in Europe) with specific dummies for children to be used. The dummies include hardware sensors for monitoring accelerations, loads and other signals and each dummy is developed for a specific scenario, but there are limitations of these dummies, such as only a specific age or calibration just for a specific test. Taking into account that the consequence of a traffic accident is highly influenced by the stature of the body, virtual human body models, including those for children, start to play a significant role because they can be scaled or even personalized towards a particular population or even a particular person. The paper contributes to the field of vehicle safety technology concerning child restraint systems development, assessment and optimization with a virtual numerical approach. The goal of the paper is to exploit the previously developed scaling algorithm to create a virtual model of a six-year-old (6YO) child and to compare its response to the virtual dummy used for child safety in order to propose an automatic scaling process for a population-based vehicle safety assessment. The automatic scaling algorithm developing virtual human body models for a given age and gender is used to create the virtual 6YO child model. The algorithm scales body dimensions and particular segments' mass and the flexibility of the body is driven by flexindex and stiffness scaling. The performance of the automatically developed virtual 6YO child model was tested in frontal and lateral directions. The frontal response was tested with a standard sled test simulation using the standardized AAMA pulse in the frontal direction. The lateral response was tested with a side barrier impact test. The results of both tests were compared to the validated virtual Q6 Child Dummy FE model. The paper shows good performance of the automatic scaling process for developing 6YO virtual model for safety assessment. The automatically developed 6YO child model corresponds well from both the anthropological point of view and performance point of view to the existing validated dummy model.

Mutagaana, Festo

6.0.101 - Piston Sealing System Structure Design for Automobile's Lightweight Auto-Transmission

SAE-PP-002572/4/2021

Current automobile's auto-transmission has problems of defects and cost reduction because of welding process and very complicated assembly process due to individualized transmission piston and sealing components. Also, size and heavy weight of transmission piston components are the source of low mileage because they are made of aluminum, steel material. In this study, therefore, we perform structure design for piston sealing system which integrates piston and sealing material for automobile's lightweight auto-transmission. Also performed stress analysis through finite element analysis to secure required suitable strength when internal pressure is applied after assemble.

Mutagaana, Festo

2.0.101 - Experimental Study of cooling of Continuously Variable Transmission (CVT) in Scooter

SAE-PP-002102/1/2021

The continuously variable transmission (CVT), which was conceptualized more than 500 years ago, is just now beginning to replace traditional transmissions in some automobiles. It is mostly used in scooter transmission. Engine power is transmitted to wheel through belt drive between two pulleys. The diameter of belt contact with pulley can change continuously and hence provide infinite gear ratios between driver and driven shafts. This technology leads to a smoother ride of vehicle. Heat is generated inside CVT due to friction between drive belt and clutch pulley. Amount of heat generated is even more due to clutch slippage during acceleration and deceleration. This will affect the service life of CVT components such as front movable drive (FMD), clutch pulley, clutch outer, and belt. In scooters generally, air cooling is preferred over liquid cooling. Cooling is achieved by incorporating centrifugal fan inside CVT housing. For better durability/service life, the degree of heat generated at CVT components should be minimal. The objective of this work is to identify the parameters causing change in temperature of CVT components and to evaluate its surface temperature in accordance with changed parameters. With reference to this, experiments were conducted with requisite design modification inside CVT housing, which enhances cooling effect. Amongst, variables determining air flow rate, are studied and their effect on temperature inside CVT housing is observed experimentally. Keeping the previous variables unaltered, further design modifications related to air flow pattern are done and cumulative effect of all variables is observed. Experiments were performed on an 110cc scooter engine by following customer driving pattern on chassis dynamometer. Results showed that design modifications intended for better cooling effect, has brought down temperature at CVT components. So, desired cooling effect is observed inside CVT housing imparting better service life of CVT components.

Mutagaana, Festo

Preignition Rating of Spark Plugs

J549_202006 (Current)

6/15/2020

This SAE Recommended Practice describes the equipment and procedures used in obtaining preignition ratings of spark plugs.

Ignition Standards Committee

CO2 Neutral Heavy-Duty Engine Concept with RCCI Combustion Using Seaweed-based Fuels

2020-01-0808

4/14/2020

This paper focusses on the application of bioalcohols (ethanol and butanol) derived from seaweed in Heavy-Duty (HD) Compression Ignition (CI) combustion engines. Seaweed-based fuels do not claim land and are not in competition with the food chain. Currently, the application of high octane bioalcohols is limited to Spark Ignition (SI) engines. The Reactivity Controlled Compression Ignition (RCCI) combustion concept allows the use of these low carbon fuels in CI engines which have higher efficiencies associated with them than SI engines. This contributes to the reduction of tailpipe CO2 emissions as required by (future) legislation and reducing fuel consumption, i.e. Total-Cost-of-Ownership (TCO). Furthermore, it opens the HD transport market for these low carbon bioalcohol fuels from a novel sustainable biomass source. In this paper, both the production of seaweed-based fuels and the application of these fuels in CI engines is discussed. Ethanol and butanol are considered as the most viable fuels derived from seaweed. The potential of these fuels has been evaluated for the dual-fuel RCCI mode regarding efficiency and NOx emissions. The operating conditions that have been varied are mainly the fuel blend ratio (BR), fuel injection timing, and EGR rate on both a HD single-cylinder and on a HD multi-cylinder engine. The results for E85/diesel-RCCI demonstrate that CI engine-like efficiencies are feasible. The gross Indicated Thermal Efficiency (ITE) reaches up to 52% and 46.5% using E85 in a single-cylinder and a multi-cylinder engine, respectively. The first results using biomass based butanol show greater difficulty in realizing targeted efficiencies on the multi-cylinder engine due to the higher fuel reactivity and higher boiling temperature than ethanol. The gross ITE reaches up to 51.6% and 38.5% using butanol in a single-cylinder and a multi-cylinder engine, respectively. The demonstrated potential of seaweed-based fuels is an important driver for upscaling the production process of these fuels. Furthermore, future development activities will focus on improving the brake thermal efficiency of the RCCI engine running on seaweed-based fuels. Improving the low reactivity fuel-air mixture preparation will be key to achieve this.

Seykens, Xander, Bekdemir, Cemil, Han, Jinlin, Willems, Robbert, Van Hal, Jaap

Numerical Investigation of the Combustion Kinetics of Partially Premixed Combustion (PPC) Fueled with Primary Reference Fuel

2020-01-0554

4/14/2020

This work numerically investigates the detailed combustion kinetics of partially premixed combustion (PPC) in a diesel engine under three different premixed ratio fuel conditions. A reduced Primary Reference Fuel (PRF) chemical kinetics mechanism was coupled with CONVERGE-SAGE CFD model to predict PPC combustion under various operating conditions. The experimental results showed that the increase of premixed ratio (PR) fuel resulted in advanced combustion phasing. To provide insight into the effects of PR on ignition delay time and key reaction pathways, a post-process tool was used. The ignition delay time is related to the formation of hydroxyl (OH). Thus, the validated Converge CFD code with the PRF chemistry and the post-process tool was applied to investigate how PR change the formation of OH during the low-to high-temperature reaction transition. The reaction pathway analyses of the formations of OH before ignition time were investigated. It was found that in the case of PR0%, the second isomerization from C7H14OOH2-4O2 to NC7KET24 and the decomposition of NC7KET24 contributed 27.6% and 46.46% of OH formation respectively. The contribution of AC8H16OOH-B to the formation of OH was just 12.13%. It can be concluded that the low temperature oxidation reactions of n-heptane were key steps in producing OH. While in the cases of PR30% and PR50%, because of the higher in-cylinder temperature, most of OH derived from the decomposition reaction of H2O2 that contributed 54.47% and 54.63% of OH formation respectively. Besides, in the PR30% and PR50%, the oxidation reactions of IC4H7 contributed 31.95% and 33.84% of OH formation respectively, and the oxidation reaction of IC4H6OH contributed 19.08% and 22.22% of OH formation respectively, which indicated that the oxidation of iso-octane also contributed to the production of OH. In addition, the distributions of mass fraction, production rate and representative creation reaction (RCR) of OH showed that in the case of PR30% and PR50%, the formation of OH outside the spray periphery were dominated by the reactions R394 (H2O2 (+ M) <=> 2 OH (+ M)), while that in the spray periphery were predominantly controlled by the reaction R21 (NC7KET24 => NC3H7CHO + CH3COCH2 + OH) and R125 (IC4H6OH + HO2 <=> CH2CCH2OH + CH2O + OH). Premixed fuel from port injection changed the formation pathway of OH during the oxidation of direct injection fuel through the reaction R125.

Zhao, Yuanyuan, Wang, Hu, Liu, Xinlei, Liu, Daojian, Chenchen, Wang, Zhu, Hongyan, Zheng, Zunqing, Yao, Mingfa

Is the “K Value” of an Engine Truly Fuel Independent?

2020-01-0615

4/14/2020

The octane appetite of an engine is frequently characterised by the so-called K value. It is usually assumed that K is dependent only on the thermodynamic conditions in the engine when knock occurs. In this work we test this hypothesis: further analysis was conducted on experimental results from SAE 2019-01-0035 in which a matrix of fuels was tested in a single cylinder engine. The fuels consisted of a relatively small number of components, thereby simplifying the analysis of the chemical kinetic proprieties. Through dividing the original fuel matrix into subsets, it was possible to explore the variation of K value with fuel properties. It was found that K value tends to increase slightly with RON. The explanation for this finding is that higher RON leads to advanced ignition timing (i.e. closer to MBT conditions) and advanced ignition timing results in faster combustion because of the higher pressures and temperatures reached in the thermodynamic trajectory. The Livengood-Wu integral can be employed to show that for higher octane fuels, knock onset occurs at a higher temperature and pressure. Thus, the fuel octane quality can impact the thermodynamic trajectory in the engine.

Cracknell, Roger, Kassai, Masaharu, Shiraishi, Taisuke, Festa, Andrea, Gail, Sandro, Aradi, Allen, Shibuya, Masahiko

A Real-Time Capable and Modular Modeling Concept for Virtual SI Engine Development

2020-01-05774/14/2020

Spark Ignited (SI) combustions engines in combination with different degrees of hybridization are expected to play a major role in future vehicle propulsion. Due to the combustion principle and the related thermodynamic efficiency, it is especially challenging to meet future CO2 targets. The layout and optimization of the overall system requires novel methods in the development process which feature a seamless transition between real and virtual prototypes. Herein, engine models need to predict the entire engine operating range in steady-state and transient conditions and must respond to all relevant control inputs. In addition, the model must feature true real-time capability. This work presents a holistic and modular modeling framework, which considers all relevant processes in the complex chain of physical effects in SI combustion. The basis is a crank-resolved cylinder model which describes gas exchange and compression to determine the thermodynamic state and turbulence conditions at spark-advance. Ignition and flame front combustion are modeled by a mechanistic, quasi-dimensional combustion model with a detailed consideration of combustion chamber geometry for flame-wall interaction. Cycle-to-cycle variations are imposed in a semi-empirical manner in order to provide realistic boundary conditions for the thermo-chemical knock model. The models are validated against engine measurements for a passenger car sized TGDI engine in a wide range of operating conditions covering the entire engine map. Emphasis is put on comparing pressure and heat release traces, not only for the mean cycle, but for the range of stochastic variations of 100 measured cycles. The validation results confirm a good level of agreement between measured and simulated results. To demonstrate capabilities of the proposed modeling concept, a model-based optimization is performed in a computational study, aiming at an optimization of engine efficiency under knocking constraints. The study examines two motoric measures, namely water injection and variable compression ratio. Finally, the optimized model runs in a transient drivecycle simulation. The test is performed on a HiL system to prove the model’s real-time capability.

Poetsch, Christoph, Wurzenberger, Johann, Katrasnik, Tomaz

Experimental and 1D Numerical Investigations on the Exhaust Emissions of a Small Spark Ignition Engine Considering the Cylinder-by-Cylinder Variability

2020-01-05784/14/2020

This paper reports a numerical and experimental analysis on a twin-cylinder turbocharged Spark Ignition engine carried out to investigate the cylinder-to-cylinder variability in terms of performance, combustion evolution and exhaust emissions. The engine was tested at 3000 rpm in 20 different steady-state operating conditions, selected with the purpose of observing the influence of cylinder-by-cylinder A/F ratio variations and the EGR effects on the combustion process and exhaust emissions for low to medium/high loads. The experimental outcomes showed relevant differences in the combustion evolution (characteristic combustion angles) between cylinders and not negligible variations in the emissions of the single cylinder exhaust and the overall engine one. This misalignment resulted to be due to differences in the injected fuel amount by the port injectors in the two cylinders, mainly deriving from the specific fuel rail geometry. The experimental data were then used to validate a 1D engine model, integrated with refined sub-models of turbulence, combustion, heat transfer and emissions. The model takes into account the in-cylinder production of noxious species, and their propagation in the exhaust system, up to the three-way catalytic converter. A satisfactory accuracy was reached in reproducing the overall engine performance and the combustion process in the two cylinders. In particular, the emission sub-models confirmed that the variations of the cylinder-out exhaust emissions (NOx, HC and CO) were mainly due to the non-uniform effective in-cylinder A/F ratio. The proposed numerical methodology has the potential to highlight unexpected combustion non-uniformities among different cylinders and represents a powerful support to the engine design and development. It also allows for the prediction of the overall exhaust emissions at different engine operating conditions up to the entire domain, thus assisting the engine calibration phase and reducing the experimental efforts.

Marchitto, Luca, Teodosio, Luigi, Tornatore, Cinzia, Valentino, Gerardo, Bozza, Fabio

Simulation Analysis of Early and Late Miller Cycle Strategies Influence on Diesel Engine Combustion and Emissions

2020-01-06624/14/2020

Based on the working model of a diesel engine, the influence of 2 Miller cycle strategies-Early Intake Valve Closure (EIVC) and Late Intake Valve Closure (LIVC) on the combustion and emissions of diesel engine was analyzed. Then the working condition of each Miller cycle strategies on the engine under the rated speed was optimized through the adjust of the valve timing, boost pressure and the injection timing. The research found that both delaying and advancing the closure timing of the intake valve can decrease the pressure and temperature during compression stroke, prolonging the ignition delay. However, due to the decrease of the working media inside the cylinder, the average in-cylinder temperature and soot emissions will increase, which can be alleviated by raising the boost pressure and the resulting compensation of the intake loss. The study found that together with increasing boost pressure and delaying injection timing, both EIVC and LIVC can reduce the NOx and soot emissions simultaneously. The simulation results show that while keeping the peak firing pressure the same as the original machine, M-50 together with constant peak firing pressure boosting and a 6oCA injection delay can decrease the BSFC by 1.21%, the NOx emissions by 22%, and the soot emissions by 58.1%, while M100 together with constant peak firing pressure boosting and a 4oCA injection delay can reduce BSFC by 1.56%, the the NOx emissions by 12.96%, and the soot emissions by 54.75%.

Yang, Shuai, Yang, Xiaolin, Liu, Haifeng, Feng, Zhiwei, Li, Xiuyuan

Assessment of the Ignition System Requirement on Diluted Mixture Spark Engines

2020-01-11164/14/2020

In order to face the new challenges, spark ignition engines are evolving by following some strategies and technologies. Among them, alternative combustion processes based on the dilution of the homogeneous mixture, either with fresh air or with Exhaust Gas Recirculation (EGR), are being explored. In a higher or lower extent, these changes modify in-cylinder thermodynamic conditions during the engine operation (pressure, temperature and gas composition) thus conditioning the spark ignition system requirements that will have to evolve to become more reliable and powerful. In this framework, an experimental study on the effect of the key in-cylinder conditions on the ignition system performance has been carried out in a single-cylinder spark-ignition (SI) research engine. The study includes EGR, lambda and energizing time sweeps to assess the behavior of the engine in different operating conditions. Furthermore, various Insulated-Gate Bipolar Transistors (IGBT) and spark plugs have been tested to assess the influence of these components on the ignition process at high diluted mixtures. Conclusions show that diluted mixtures (with EGR or lambda), even though they require more spark energy to achieve a stable combustion, have up to 4% benefit on indicated efficiency, providing that the combustion propagates adequately. However, at high diluted conditions the combustion is compromised, so two different approaches were explored to improve it. Whilst it was checked that increasing the clamping value of the IGBT does not necessarily imply a better combustion in all scenarios, the increment of the electrodes gap of the spark plug would require higher clamping voltage at the IGBT, and it would have a slight benefit on efficiency providing that the rest of components, in particular the coil, are adequate.

Molina, Santiago, Martin, Jaime, Novella, Ricardo, Gomez-Soriano, Josep, Padilla, Jose

Real Time Energy Management Control Strategies for an Electrically Supercharged Gasoline Hybrid Vehicle

2020-01-10094/14/2020

The high level of electric power available on a Hybrid Electric Vehicle (HEV) enables the introduction of electrical auxiliaries in addition or in substitution to the ones currently available on a conventional powertrain. Among these auxiliaries, electric Superchargers (eSC) for the improvement of the vehicle performance or electrically heated catalysts for the reduction of the light-off time of the after-treatment may dramatically affect the Energy Management System (EMS) of an HEV. Moreover, since these devices are only fluid-dynamically, but not mechanically, linked to the powertrain, they are traditionally neglected in the optimization of the powersplit between internal combustion engine and electric machines by the EMS. The aim of the current work is the development of an EMS that is able to consider in real time the overall electric energy consumption of the entire powertrain. More in detail, this activity focuses on the refinement of the Equivalent Consumption Minimization Strategy (ECMS) including the power required by an eSC installed on a turbocharged gasoline engine. This innovative EMS is tested by means of numerical simulation on a small SUV (Sport Utility Vehicle) featuring a 48 V electric network over Type Approval and Real Driving Emissions (RDE) driving cycles. The novel EMS shows promising results in terms of eSC energy management and vehicle fuel consumption compared with the baseline.

Accurso, Francesco, Zanelli, Alessandro, Rolando, Luciano, Millo, Federico

Optical Diagnostics of Isooctane and n-Heptane Isobaric Combustion

2020-01-11264/14/2020

Isobaric combustion has demonstrated a great potential to reach high thermodynamic efficiency in the advanced Double Compression Expansion Engine (DCEE) concept. It appears as one of few viable choices for applications with high-pressure combustion. At these conditions, releasing heat at a constant pressure minimizes the peak in-cylinder pressure and, hence, mitigates excessive mechanical stress on the engine. This study focuses on the effect of fuels on the multiple-injection isobaric combustion. A single-cylinder heavy-duty engine was utilized to test and compare the isobaric combustion with pure isooctane and n-heptane fuels. The engine was equipped with an optical piston to allow a bottom-view of the combustion chamber. The interactions of multiple injections and the combustion behavior were studied using high-speed acquisition of chemiluminescence. The examined isobaric cases have a peak pressure of 70 bar. For cases with high soot luminosity, a short band-pass filter was used to avoid image saturation. Fuels with short ignition delay time such as n-heptane are usually used for isobaric applications as they offer good controllability of injections. However, the study herein demonstrates that isobaric combustion can be achieved even with high octane number fuels such as isooctane. The dwell time between injections is much larger for isooctane, which allows enhanced mixing of the fuel jets with air and thus a partially premixed combustion behavior. The high-speed imaging demonstrated evidence of flame extinguishing during the sequential injection of n-heptane. This contributes to the staging of the heat release rate.

Al Ramadan, Abdullah S., Nyrenstedt, Gustav, Ben Houidi, Moez, Johansson, Bengt

Influence of Port Water Injection on the Combustion Characteristics and Exhaust Emissions in a Spark-Ignition Direct-Injection Engine

2020-01-02944/14/2020

It is well known that engine downsizing is still the main energy-saving technology for spark-ignition direct-injection (SIDI) engine. However, with the continuous increase of the boosting ratio, the gasoline engine is often accompanied by the occurrence of knocking, which has the drawback to run the engine at retarded combustion phasing. Besides, in order to protect the turbine blades from being sintered by high exhaust temperature, the strategies of fuel enrichment are often taken to reduce the combustion temperature, which ultimately leads to a high level of particulate number emission. Therefore, to address the issues discussed above, the port water injection (PWI) techniques on a 1.2-L turbocharged, three-cylinder, SIDI engine were investigated. Measurements indicate that the optimization of spark timing has a significant impact on its performance. The two factors of the water substance itself and spark advance caused by the knock mitigation are trade-offs, which eventually affect the combustion performance. Under knock limited spark advance (KLSA) condition, we find that the application of port water injection could effectively advance the combustion phasing and reduce exhaust gas temperature, which makes it possible to eliminate fuel enrichment and further enhances the fuel economy improvement at the maximum power point. As a result, about 5.2%-18.4% improvements in the fuel economy are obtained under different engine operating conditions. For the exhaust emissions, due to the increasing heat capacity of the mixture and the elimination of fuel enrichment, port water injection techniques cause an 85.3% reduction in particle number concentration. However, it shows that for a given λ, an increase in the water/fuel ratio would cause higher THC emissions, which is contributed to the occurrence of more quenching caused by higher peak combustion pressure. Finally, the potential of PWI on the engine combustion characteristics and emissions performance was revealed.

Fan, Yadong, Wu, Tianbao, Li, Xuesong, Xu, Min, Hung, David

MIMO Control of a Turbogenerator for Energy Recovery

2020-01-02614/14/2020

Market trends for increased engine power and more electrical energy on the powergrid (3kW+), along with customer demands for fuel consumption improvements and emissions reduction, are driving requirements for component electrification, including turbochargers. GTDI engines waste significant exhaust enthalpy; even at moderate loads the WG (Wastegate) starts to open to regulate the turbine power. This action is required to reduce EBP (Exhaust Back Pressure). Another factor is catalyst protection, where the emissions device is placed downstream turbine. Lambda enrichment or over-fueling is used to perform this. However, the turbine has a temperature drop across it when used for energy recovery. Since catalyst performance is critical for emissions, the only reasonable location for an additional device is downstream of it. This is a challenge for any additional energy recovery, but a smaller turbine is a design requirement, optimized to operate at lower pressure ratios. A WAVE model of the 2.0L GTDI engine was adapted to include a TG (Turbogenerator) and TBV (Turbine Bypass Valve) with the TG in a mechanical turbocompounding configuration, calibrated with steady state dynamometer data. This includes power and fuel consumption, and additionally a sensitivity analysis and knock impact assessment. Further work includes transient verification with WAVE-RT on WLTP and RDE drive cycles, estimating dynamic energy recovery, assessing electrical turbocompounding, interfacing to the powergrid, and calibration optimisation, using combined WG and TBV settings. Development of more advanced MIMO (Multiple-Input, Multiple-Output) control system algorithms and prototype testing on dynamometer or vehicle could be performed to verify design assumptions and simulation results.

Petrovich, Simon, Ebrahimi, Kambiz, Kalantzis, Nikolaos, Pezouvanis, Antonios

The Effect of Heavy-Duty Diesel Cylinder Deactivation on Exhaust Temperature, Fuel Consumption, and Turbocharger Performance up to 3 bar BMEP

2020-01-14074/14/2020

Diesel Cylinder Deactivation (CDA) has been shown in previous work to increase exhaust temperatures, improve fuel efficiency, and reduce engine-out NOx for engine loads up to 3 bar BMEP. The purpose of this study is to determine whether or not the turbocharger needs to be altered when implementing CDA on a diesel engine. This study investigates the effect of CDA on exhaust temperature, fuel efficiency, and turbocharger performance in a 15L heavy-duty diesel engine under low-load (0-3 bar BMEP) steady-state operating conditions. Two calibration strategies were evaluated. First, a “stay-hot” thermal management strategy in which CDA was used to increase exhaust temperature and reduce fuel consumption. Next, a “get-hot” strategy where CDA and elevated idle speed was used to increase exhaust temperature and exhaust enthalpy for rapid aftertreatment warm-up. The “stay-hot” CDA strategy demonstrated increased exhaust temperatures up to 200°C while simultaneously reducing fuel consumption by 5-40% depending on the operating condition. The “get hot” CDA strategy demonstrated up to 200°C increases in exhaust temperature in addition to 10kW increase in exhaust enthalpy over baseline operation. The effect of CDA on the turbocharger performance was noticeable, but only affected a small part of the engine operating map where CDA was active. Overall, turbocharger efficiency decreased with CDA; however, the reduced pumping work from the deactivated cylinders still provided a fuel efficiency benefit. Examining the individual components, the compressor efficiency decreased with CDA due to the reduced engine air flow while the turbine efficiency increased. The study concluded that the same turbocharger as a non-CDA engine should still be selected for diesel CDA engines.

Morris, Andrew, McCarthy, James

A Holistic Approach to Develop a Common Rail Single Cylinder Diesel Engine for Bharat Stage VI Emission Legislation

2020-01-13574/14/2020

The upcoming Bharat Stage VI (BS VI) emission legislation has put enormous pressure on the future of small diesel engines which are widely used in the Indian market. The present work investigates the emission reduction potential of a common rail direct injection single cylinder diesel engine by adopting a holistic approach of lowering the compression ratio, boosting the intake air and down-speeding the engine. Experimental investigations were conducted across the entire operating map of a mass-production, light-duty diesel engine to examine the benefits of the proposed approach and the results are quantified for the modified Indian drive cycle (MIDC). By reducing the compression ratio from 18:1 to 14:1, the oxides of nitrogen (NOx) and soot emissions are reduced by 40% and 75% respectively. However, a significant penalty in fuel economy, unburned hydrocarbon (HC) and carbon monoxide (CO) emissions are observed with the reduced compression ratio. Intake air boosting using a mechanically driven supercharger could overcome the penalty in HC and CO emissions. However, the mechanical frictional losses of the supercharger resulted in a further penalty in the fuel economy. The reduced cylinder pressure due to lower compression ratio and the increased air availability due to intake air boosting could be utilized to improve the full-load performance of the engine by 28%. Further, the advantage of improved engine performance was utilized to down-speed the engine by optimizing the transmission gear ratios without compromising the acceleration performance of the vehicle. Overall, with this holistic approach, soot emission could be reduced by a significant margin of 83% whereas the NOx emission is reduced by 5.8%. Moreover, the HC and CO emissions could be reduced by 17.6% and 30.9% respectively. Furthermore, the fuel economy at the vehicle-level could be improved by 5.4% while improving the in-gear acceleration performance by 9%. Thus, the proposed approach is found to be extremely beneficial to develop small, light-duty diesel engines with compliance on future emission regulations. The reasons behind the observed benefits are explained in detail based on the measured in-cylinder pressure and calculated heat release data.

Vellandi, Vikraman, Ramesh, A., Krishnasamy, Anand

The Application of E-Fuel Oxymethylene Ether OME1 in a Virtual Heavy-Duty Diesel Engine for Ultra-Low Emissions

2020-01-03494/14/2020

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

McLaren: The Engine Company

R-4853/13/2020

McLaren: The Engine Company is the previously untold story of McLaren Engines, an American company founded in 1969 by Bruce McLaren and his partners to build engines for McLaren's legendary Can-Am and Indy Cars. From this base in suburban Detroit were born the mighty big-block Chevrolet V8s that powered the iconic orange cars to two of their five consecutive Cam-Am championships. McLaren's busy dyno rooms also spawned the howling turbo Offenhausers that put Mark Donohue and Johnny Rutherford in Victory Lane at Indianapolis three times between 1972 and 1976. For decades this non-descript shop was the hotbed of horsepower for factories and top independents alike. McLaren Engines developed the turbocharged Cosworth DFV Formula 1 engine that powered Indy cars for both Team McLaren and Penske Racing. It rendered BMW's turbo engine for U.S. IMSA racing that later became BMW's Formula 1 weapon. The long list of race engines developed here powered Buick Indy and IMSA cars, BMW GTP cars, Cadillac LeMans prototypes, Porsche Trans-Am 944s and David Hobbs' F5000 single seaters. There were McLaren-built big-block turbo V8s for offshore boat racing and even a Cosworth-Vega engine for American dirt tracks! Author Roger Meiners combines his life-long passion for motor racing and technology with his historian's sensibilities to make the engines, cars, and key personalities come alive within this book's pages. Ride along with Meiners as he uncovers little-known details of the company's transition from a race shop to an engineering company, developing lust-worthy performance cars such as the sensational 1987 Buick GNX, the 1989 Pontiac Grand Prix Turbo, the FR500 Ford Mustang concept, and other projects that the public never saw. Today the company, known as McLaren Engineering, is a subsidiary of Canada-based Linamar Corporation, and is sought after by global automakers for its unrivaled testing, development and manufacturing capability.

Meiners, Roger

Study on Multivariable Control for Air and Charging System of Gasoline Engine

07-12-02-00062/7/2020

This study explores the multivariable multi-input–multi-output technique based on nonlinear models to decouple actuator interaction and to reduce the calibration workload, as well as to increase control performances, under transient conditions, and also explores the robustness on model uncertainties and system parameter variations. The development of a nonlinear dynamic physical model of air in gasoline engine and its charging system provides the for the control technology. The model uses feedback linearization control to decouple the interaction between actuators and compensate the nonlinearity. A new set of inputs was defined through inversing the differential equation of the system. The relationship between the new inputs and the output is linear and decoupled. In addition, a linear control module is used to ensure transient and steady-state performance as well as closed-loop robustness. The control method has been confirmed on the bench test with a three-cylinder gasoline engine prototype for hybrid electric vehicles. Transient test results show that the controller is able to coordinate the actuator to achieve the targets.

Wang, Wei, Cai Zhen, Jiang, Liu Shao, Fei

Engineering the world's fastest tractor

20TOFHP02_052/1/2020

JCB worked with design and engineering specialists to build a spectacular speed record-breaker that topped 150 mph. For farmers in a hurry, JCB's Fastrac series agricultural tractors are capable of speeds up to 43 mph (69 km/h) in stock form. But the British company believes in challenging its engineers to improve the breed, and in doing so they've taken the concept of a high-speed ag tractor to new heights. In June 2019, a JCB-modified machine, called Fastrac One, set a new world (modified) tractor speed record, averaging more than 100 mph. Then in November, the JCB engineers, working with counterparts at Ricardo, GKN Wheels & Structures, and Williams Advanced Engineering, raised the record by 32 mph to establish another Guinness World Record: 135.19 mph (217.57 km/h), averaged over two runs at Elvington Airfield in Britain. In one of its passes through the speed trap, the Fastrac Two tractor reached 153.77 mph (247.47 km/h).

Birch, Stuart

High Efficiency by Miller Valve Timing and Stoichiometric Combustion for a Naturally Aspirated Single Cylinder Gas Engine

2019-32-05881/24/2020

Small-scale cogeneration units (Pel < 50 kW) frequently use lean mixture and late ignition timing to comply with current NOx emission limits. Future tightened NOx limits might still be met by means of increased dilution, though both indicated and brake efficiency drop due to further retarded combustion phasing and reduced brake power. As an alternative, when changing the combustion process from lean burn to stoichiometric, a three-way-catalyst allows for a significant reduction of NOx emissions. Combustion timing can be advanced, resulting in enhanced heat release and thus increased engine efficiency. Based on this approach, this work presents the development of a stoichiometric combustion process for a small naturally aspirated single cylinder gas engine (Pel = 5.5 kW) originally operated with lean mixture. To ensure low NOx emissions, a three-way-catalyst is used. In order to achieve high engine efficiency, measures implemented include Miller valve timing, optimized intake system, reduced engine speed and increased compression ratio. In the first step, a detailed 1D engine cycle simulation model was used to investigate the efficiency benefit of Miller valve timing and increased compression ratio. Within the numerical study, inlet valve closing timing and intake pipe length were varied, yet a closed-loop control was implemented to maintain a constant effective compression ratio of 14.66 by adjusting geometrical compression ratio for each configuration. Subsequently, the most expedient valve timing was designed using multi-body simulation of the inlet valve train, while increased compression ratio was achieved by modifying the series piston bowl geometry. Engine trials agree with simulation results and show highest efficiency for a Miller valve timing closing +15 °CA later to the series valve timing and geometrical compression ratio of 15.36. Compared to the series lean burn engine, indicated and brake efficiency increase by 3.2 %-points to 39.0 % and by 3.9 %-points to 34.4 %, respectively, while maintaining original brake power of Pe = 6.1 kW. Finally, an experimental study accompanied by 3D-CFD simulations was conducted to investigate the potential of optimized piston geometry to further increase efficiency. However, results reveal only minor effect of piston geometry on efficiency, what is likely stemming from interrelation of combustion efficiency, wall heat losses and heat release rate.

Judith, Jörn, Neher, Denis, Kettner, Maurice, Schwarz, Danny, Klaissle, Markus

Rework of an in-line two-cylinder engine for the application in Formula Student

2019-32-05321/24/2020

Formula Student is an international design competition, where students all over the world develop, design and build their own race car and afterwards compete with each other at different disciplines at events worldwide. The development process includes every module of the race car and the team of joanneum racing graz has focused on the powertrain since the beginning. The following paper contains an overview of the reworking process of an in-line two-cylinder engine for the application in Formula Student. The intention was to increase the BMEP and at the same time reach a desired power/weight ratio of the engine. The process of selecting the most appropriate turbocharger by means of experimental testing on an engine dynamometer, as well as its optimization by means of numerical simulation, is outlined. Subsequently, the paper discusses the challenges regarding valve timing and finding the best trade-off between power and residual gas with the help of 1D-simulations. The necessary implementation of an intercooler and its efficiency optimization is also addressed. Finally, the calibration and optimization of the setup on the engine test bed is presented. After the selection of the most suitable turbocharger for the engine and the reworking of its compressor side, it was possible to achieve a maximum boost pressure of 2.76 bar absolute. Charge air cooling and closed loop boost control guaranteed fast boost pressure build up. Together with the optimized cam timing, which reduced residual gas, and an increased compression ratio, the overall torque output of the engine resulted in 135 Nm at 4000 rpm and a maximum power of 63 kW at 6000 to 6500 rpm. The overall target of increasing the BMEP of the selected engine and at the same time achieving a lower power/weight ratio than the previous engine (FS133) was accomplished with a final value of 0.81 kW/kg.

Feigl B.Sc, Michael, Rößmann B.Sc, Dominik, Michael Trzesniowski, FH-Prof. DI

Influence of the Kind of Fuel Kind in the Ignition of Diesel Dual Fuel Operation with Introduced Natural Gas Combining EGR and Supercharging

2019-32-0581

1/24/2020

A number of studies in diesel dual fuel (DDF) operation which introduces natural gas from the intake pipe and ignites it by a diesel fuel injection in the combustion chamber have been conducted using conventional diesel engines. The present study investigated the influence of the ignition fuel on engine performance, combustion characteristics, and emissions with a combination of EGR and supercharging in DDF operation. The experiments employed iso-pentanol blended fuels for the ignition. Isopentanol is a next generation bio-alcohol fuel produced from cellulosic biomass, and actual use can be expected. The experiments were conducted at two CNG supply rates, 0% (ordinary diesel operation) and at a 40±4% (DDF operation) energy basis, and with EGR rates varied from 0 to 26%. The boost pressure was set at two conditions, 100 kPa (naturally aspirated, N/A) and 120 kPa (supercharged, S/C) with a supercharger. Four kinds of ignition fuels were used, JIS No.2 diesel fuel as a reference, neat methyl laurate (LME) which is a major component of coconut oil biodiesel, and two iso-pentanol blended fuels with 30% mass ratios, DiP30 (70% diesel and 30% iso-pentanol) and LiP30 (70% LME and 30% iso-pentanol). The results showed that regardless of the ignition fuel, the DDF operation with EGR and also supercharging resulted in substantial reductions in NOx and smoke emissions. However, the brake thermal efficiency decreased with increasing EGR rates, and with much longer ignition delays this tendency was more pronounced for the two iso-pentanol blends.

Yoshimoto, Yasufumi, Kinoshita, Eiji, Otaka, Takeshi