Browse Topic: Exhaust systems

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Acoustic Assessment in a Small Displacement Diesel Engine2014-32-01291/30/2026
In the last years, the increasing concern for the environmental issues of IC engines has promoted the development of new strategies capable of reducing both pollutant emissions in atmosphere and noise radiation. Engines can produce different types of noise: 1) aerodynamic noise due to intake and exhaust systems and 2) surface radiated noise. Identification and analysis of noise sources are essential to evaluate the individual contribution (injection, combustion, piston slap, turbocharger, oil pump, valves) to the overall noise with the aim of selecting appropriate control strategies. Previous paper focused on the combustion related noise emission. The research activity aimed at diagnosing and controlling the combustion process via acoustic measurements. The optimal placement of the microphone was selected, where the signal was strongly correlated to the in-cylinder pressure development during the combustion process. Analysis and processing of the sound emission allowed the acoustic contribution of the combustion event to be isolated. Some indices capable of relating the combustion noise radiation back to the combustion development were defined. This paper presents an experimental activity devoted to analyze the entire noise generation process of a small displacement diesel engine. The purpose was to identify the contribution of the different sources (mechanical, combustion, fluid dynamic) to the overall emission. The methodology here proposed analyze the specific signature in the frequency domain of each source. The final objective was to use the microphone signal acquired in a proper selected location, to obtain indications about the effective strategies to achieve noise reduction. The repetitiveness of the measurements was guaranteed by a network encircling the engine. Microphones were placed in different positions and tests were performed in the complete engine operative field. In the paper, the experimental set-up is described, the methodology is presented. Results are then shown and discussed.
Chiatti, Giancarlo, Recco, Erasmo, Chiavola, Ornella, Conforto, Silvia
HELICOPTER TURBOSHAFT ENGINE IDLE POWER SCHEDULINGAIR4121 (Current)11/26/2025
The purpose of this AIR (Aerospace Information Report) is to provide aircraft and engine designers with a better understanding of helicopter turboshaft engine idle power characteristics and objectives to be considered in the design process. Idle is the lowest steady state power setting. At this setting, the engine typically does not produce enough power to obtain governed output shaft speed (i.e. the shaft speed is determined by the load imposed by the aircraft). In the aircraft, the engine is typically stabilized at this power setting after starting, prior to taxi and for some period of time after rotor shutdown for cool down prior to engine shutoff. Traditionally, the aircraft designer wants idle power scheduled as low as possible and of course, does not want any resulting aircraft operational difficulties such as overcoming the rotor brake. The engine designer, however, desires a higher scheduled power because of the reduced probability of engine operational problems. The attributes of conflicting idle desires are discussed. Other inputs are also considered to establish the engine idle power settings. The information contained herein will assist in the early design phase and ultimately will result in a more optimum match between engine and aircraft requirements.
S-12 Powered Lift Propulsion Committee
Verifying large alternate product code for an JA GV document - JA1124XXJA1224XX/NEW/00000000000000000001_202511 (Current)11/24/2025
Verifying large alternate product code for an JA GV document - JA1124XX
Active Safety Systems Standards Committee
TightAIR12122024A (Current)12/12/2024
New Scoop
A-6 Aerospace Actuation, Control and Fluid Power Systems
Engine Installed Performance Testing ActivitiesF-0080-2024-12975/7/2024
T-625 helicopter, created by the Turkish Aerospace Helicopter Group, serves as a light utility multi role helicopter. It is powered by a pair of CTS800-4AT turboshaft engines, which were developed by the Light Helicopter Turbine Engine Company (LHTEC). This paper presents aspects of performance characteristics for air intakes, exhaust system and engine vents in powerplant integration of the T-625 helicopter, together with the results of engine installed performance flight test campaign, which are performed to determine the engine installation losses.
Mayda, Anil, Çakıroğlu, Taylan, Ezertaş, Ahmet Alper, Bayat, Akay, Okatan, Lütfullah, Sancar, Emre, Daldal, Burak
Modeling Activities of Propulsion System Engine Installation SurveyF-0080-2024-13525/7/2024
The multi-role utility helicopter T625 GÖKBEY is designed by Turkish Aerospace and it is equipped with a pair of two-spool CTS800-4AT turboshaft engine developed by Light Helicopter Turbine Engine Company (LHTEC). Components of the cowlings, intakes and exhausts were designed with supplementing CFD analyses and performance of various alternatives were evaluated. Final designs were achieved based on the helicopter performance and engine limits. In order to verify the estimated engine installed performance in design phase, performance of the instrumented engine with its integrated equipment on the platform is examined using flight test data. This paper focuses on the CFD simulations based performance predictions of the air induction system, exhaust system, and IPS blower exhaust. A comprehensive study is assessed to create more realistic models by using flight test data.
Sancar, Emre, Ezertaş, Ahmet Alper, Bayat, Akay, Çakıroğlu, Taylan, Daldal, Abdurrahman Burak
Investigation of a Second Exhaust Valve Lift to Improve Combustion in a Methane - Diesel Dual-Fuel Engine2022-01-04663/29/2022
In recent years, the utilization of dual-fuel combustion has gained popularity in order to improve engine efficiency and emissions. With its high knock resistance, methane allows operation in high compression diesel engines with lower risk of knocking. With the use of diesel fuel as an ignition source, it is possible to exploit the advantages of lean combustion without facing problems to provide the high amount of ignition energy necessary to burn methane under such operating conditions. Another advantage is the variety of sources from which the primary fuel can be obtained. In addition to fossil sources, methane can also be produced from biomass or electrical energy.As the rate of substitution of diesel by methane increases, the trade-off between nitrogen oxide and soot is mitigated. However, emissions of carbon monoxide and unburned methane increase. Since carbon monoxide is toxic and methane has 25 times the global warming potential of carbon dioxide, these emission components pose a problem. Because of the stability of the molecule, methane catalysts require an exhaust gas temperature of over 500 °C in order to work effectively.In this work, the effect of conventional cooled external exhaust gas recirculation (EGR) and additional hot internal EGR are investigated for different substitution rates in a nonroad tractor engine converted to dual-fuel operation. The internal EGR rate is controlled by a variable second exhaust valve lift during the intake stroke - an approach which promises to benefit dual-fuel engines by increasing the in-cylinder gas temperature, thus favoring more complete combustion. A simulation model of the engine is used to determine the internal EGR rates and in-cylinder temperatures based on the experimental data. When internal EGR is used in combination with external EGR, the resulting emissions show additional reductions in nitrogen oxide (up to -51 %), carbon monoxide (up to -18 %) and methane (up to -28 %) with increasing internal EGR, while still maintaining low soot levels due to the substitution of diesel fuel for methane.
Mueller, Florian, Guenthner, Michael, Weigel, Alexander, Thees, Matthias
2.0.101 - Experimental Study of cooling of Continuously Variable Transmission (CVT) in ScooterSAE-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
Spark Arrester Test Procedure for Large Size EnginesJ342_202010 (Current)10/6/2020
This SAE Recommended Practice establishes equipment and procedures for the evaluation of the effectiveness and other performance characteristics of spark arresters or turbochargers used on the exhaust system of large engines normally used in a railroad locomotive, stationary power plant, and other similar applications. This document does not cover applications requiring flame arresting, exhaust gas cooling, or isolation from explosive gases. Two test methods are presented: a laboratory test using ambient air (cold test) and an engine test using exhaust gases (hot test). The hot test is preferred. Arresters tested by the provisions of this document can be expected to perform as tested when tilted no more than 45 degrees from their normal position. Test results from a spark arrester or turbocharger evaluated by the hot test can be applied to different engines of similar design, provided the data shows it to be effective in the applicable flow ranges. Certain design and performance characteristics, which represent current requirements by regulatory agencies for qualification and approval under this document, are listed in Appendix A.
SAE IC Powertrain Steering Committee
Medium/Heavy-Duty E/E Systems Diagnosis NomenclatureJ2403_202008 (Historical)8/3/2020
This SAE Recommended Practice is applicable to all E/E systems on MD and HD vehicles. The terms defined are largely focused on compression-ignited and spark-ignited engines. Specific applications of this document include diagnostic, service and repair manuals, bulletins and updates, training manuals, repair data bases, under-hood emission labels, and emission certification applications. This document focuses on diagnostic terms, definitions, abbreviations, and acronyms applicable to E/E systems. It also covers mechanical systems which require definition. Nothing in this document should be construed as prohibiting the introduction of a term, abbreviation, or acronym not covered by this document. The use and appropriate updating of this document is strongly encouraged. Certain terms have already been in common use and are readily understood by manufacturers and technicians, but do not follow the methodology of this document. These terms fall into three categories: a Acronyms that do not logically fit the term. b Acronyms existing at the component level (i.e., their terms contain the base word or noun that describes the generic item that is being further defined). c Acronyms for terms that appear to contain the base word, but are frequently used as a modifier to another base word. (This use may possibly be thought of as following the methodology, since the acronym is normally used as a modifier.)
Truck Bus Control and Communications Network Committee
Application Layer - DiagnosticsJ1939/73_202006 (Historical)6/9/2020
SAE J1939-73 defines the SAE J1939 messages to accomplish diagnostic services and identifies the diagnostic connector to be used for the vehicle service tool interface. Diagnostic messages (DMs) provide the utility needed when the vehicle is being repaired. Diagnostic messages are also used during vehicle operation by the networked electronic control modules to allow them to report diagnostic information and self-compensate as appropriate, based on information received. Diagnostic messages include services such as periodically broadcasting active diagnostic trouble codes, identifying operator diagnostic lamp status, reading or clearing diagnostic trouble codes, reading or writing control module memory, providing a security function, stopping/starting message broadcasts, reporting diagnostic readiness, monitoring engine parametric data, etc. California-, EPA-, or EU-regulated OBD requirements are satisfied with a subset of the specified connector and the defined messages.
Truck Bus Control and Communications Network Committee
Initial Investigations into the Benefits and Challenges of Eliminating Port Overlap in Wankel Rotary Engines2020-01-02804/14/2020
The Wankel rotary engine historically found limited success in automotive applications due in part to poor combustion efficiency and challenges around emissions. This is despite its significant advantages in terms of power density, compactness, vibrationless operation, and reduced parts count in relation to the 4-stroke reciprocating engine, which is now-dominant in the automotive market. A large part of the reason for the poor fuel economy and high hydrocarbon emissions of the Wankel engine is that there is a very significant amount of overlap when the ports are opened and/or closed by the rotor apices (so-called peripheral ports). This paper investigates the benefits of zero overlap from a production engine with this characteristic and the effect of configuring a peripherally-ported Wankel engine in such a manner. As discussed in the paper, arranging this condition for peripherally-ported engines unfortunately reduces the trapped compression and/or expansion ratios significantly, such that when naturally-aspirated operation is simulated, a large reduction in performance ensues. In order to demonstrate the potential of zero port overlap in Wankel engines with respect to emissions, a 2007 model year Mazda RX-8 was rebuilt, run-in, degreened, and tested on a chassis dynamometer. As standard, the engine in this vehicle is configured with no port overlap through the adoption of side intake and exhaust ports. This testing was performed in order to see subjectively how successful such an approach could be in controlling emissions. The vehicle easily met Euro 5 limits for all criteria emissions and was even better in terms of hydrocarbon emissions versus Euro 6 on the WLTP cycle, giving the lie to the belief that a Wankel engine can no longer meet current automotive emissions targets. The analytical work reported here studies the result of eliminating overlap on the performance of a peripherally-ported single-rotor Wankel engine using a 1-D model. This was implemented and correlated to the in-production Advanced Innovative Engineering (UK) Ltd 225CS engine used in the UK government-funded ADAPT project. The initial port study focused on advancing and retarding the exhaust and intake port respectively to achieve zero port overlap and then sweeping their zero-overlap positions together around the trochoid housing. The best location for the ports was then identified; this was essentially an “Otto” timing set, with broadly equal compression and expansion ratios. Notwithstanding this, potential performance was found to be severely curtailed, as was to be expected given the marked reduction in trapped compression and/or expansion ratios necessary due to peripheral porting. Countermeasures to this reduction are discussed. Those that will be studied later in the project will be reported in a later publication.
Turner, James, Turner, Matthew, Vorraro, Giovanni, Thomas, Toby
Parametric Representation of the Entire Pressure Drop Evolution during Particulate Filter Loading2020-01-14334/14/2020
Improved understanding and compact descriptions of the pressure drop evolution of Particulate Filters (both for diesel and gasoline powered vehicles) are always in demand for intelligent implementations of exhaust emission system monitoring and control. In the present paper we revisit the loading process of a particulate filter focusing on a parametric description of the deep bed-to-cake transition in the light of recent progress in the understanding of soot deposit structure, growth dynamics and evolution. Combining experimental data, simulation models and information theoretic concepts we provide a closed-form representation of the entire evolution of pressure drop (from the initial clean state up to the evolving linear cake growth regime) parameterized in terms of the physical parameters of the system (filter and particle structure/geometry and flow properties). The representation is shown to be in excellent agreement with the available experimental data and it opens the door for improved on-board monitoring/control of particulate filter systems.
Konstandopoulos, Athanasios G., Metallinou, Rozina
Simulation of Aftertreatment Thermal Management Strategies for Low-Load Operation2020-01-03594/14/2020
The low-NOx regulation for heavy duty trucks proposed by California’s Air Resources Board (CARB) will present a significant challenge to truck, engine and aftertreatment system manufacturers. This regulation will include a new test cycle representative of low-load operation. With low-load cycles, NOx conversion by the SCR (selective catalytic reduction) system is limited primarily by the exhaust temperature; thus, thermal management will dominate development. Simulation can be used to examine different thermal management strategies, and to define high-level requirements for new components. In this study, modeling was used to investigate SCR performance on two different low-load cycles, including the one selected by CARB for the low-NOx regulation. First, the “thermal deficit” of the cycle was quantified using a constant heat input. Next, direct heating of the exhaust with a fuel mini-burner or an electric heater, using realistic controls, was simulated to determine their capability to overcome the thermal deficit. For comparison, the performance of a dual-injection SCR system on these cycles was also modeled.
Harris, Thomas
First-Principles Research on Adsorption of NOx on Pt Cluster and BaO Cluster Supported by γ-Al 2 O 3 (110) Surface2020-01-03574/14/2020
Lean NOx trap (LNT) is a great potential NOx abatement method for lean-burn gasoline engines in consideration of exhaust aftertreatment cost and installation space. NOx firstly is adsorbed on storage sites during the lean-burn period, then reduced to N2 under catalysis of the catalyst sites in the rich-burn phase. There must be a spillover of NOx species between both types of sites. For a better understanding of this spillover process of NOx species between Pt (as the catalytic center) and BaO sites (as storage components in commercial catalyst), this work focused on the vital first step of spillover, the adsorption of NOx on clean substrate surface (γ-Al2O3 (110) surface) and Ba\Pt cluster supported by the surface. Based on first principles software VASP (Vienna Ab-initio Simulation Package), the most stable adsorption structures of NO with Pt3 clusters and (BaO)3 clusters on carrier γ- Al2O3 (110) surface were confirmed and the adsorption energy of these structures were compared. Meanwhile electronic structure analysis of these adsorption systems was investigated by analyzing DOS (density of state), Bader charge, charge density difference and COHP (crystal orbital Hamilton population). From electronic structure analysis methods mentioned above, a better view of electron transfer and bond formation between gas phase NOx molecules and supported BaO or Pt cluster was obtained. This work has laid a good foundation for the further research of NOx adsorption and reduction of LNT by providing a more microscopic explanation of NOx species spillover mechanism.
Li, Shilong, Zhang, Yanke, zhao, Jin
Calibration and Parametric Investigations on Lean NOx Trap and Particulate Filter Models for a Light Duty Diesel Engine2020-01-06574/14/2020
To comply with the stringent future emission mandates of light-duty diesel engines, it is essential to deploy a suitable combination of emission control devices like diesel oxidation catalyst (DOC), diesel particulate filter (DPF) and DeNOx converter (LNT or SCR). Arriving at optimum size and layout of these emission control devices for a particular engine through experiments is both time and cost-intensive. Thus, it becomes important to develop suitable well-tuned simulation models that can be helpful to optimize individual emission control devices as well as arrive at an optimal layout for achieving higher conversion efficiency at a minimal cost. Towards this objective, the present work intends to develop a one-dimensional Exhaust After Treatment Devices (EATD) model using a commercial code. The model parameters are fine-tuned based on experimental data. The EATD model is then validated with experiment data that are not used for tuning the model. Subsequently, the model was used for studying the effects of geometrical parameters of the after-treatment devices like diameter and length on the conversion efficiency and the pressure drop. The experimental investigations are done in a single-cylinder light-duty diesel engine currently used in Indian market fitted with a Lean NOx Trap (LNT), Diesel Oxidation Catalyst (DOC) and Diesel Particulate Filter (DPF). From the Indian Driving Cycle (IDC) cycle, 8 representative operating conditions were chosen and experiments were conducted at steady state at these conditions. The chemical kinetic parameters, friction loss and heat transfer coefficient of the one-dimensional model were tuned using five of the 8 experimental data sets. The remaining three data sets were used to validate the predictions with no further tuning. The model could predict the conversion efficiency, pressure drop and outlet temperature with better accuracy. The calibrated model was then used to predict the effect of geometrical parameters. The effects of varying length and diameter of the EATD were studied with this calibrated model. The results obtained show that increasing the diameter is more effective than increasing the length for enhanced conversion efficiency and reduced pressure drop across LNT. For LNT, increasing the diameter by 5% and reducing the length by 10% compared to the existing design, results in a 1% reduction in volume, an 11% increase in pressure drop with 1.6% higher conversion efficiency. For cDPF, increasing the diameter by 10% and reducing the length by 10% results in a 9% increase in volume, a 17% reduction in pressure drop with 1.5% higher conversion efficiency. Thus, the current model and methodology can be used for optimizing the size of EATD.
Bagavathy, S. Suresh, Ramesh, A, Krishnasamy, Anand, Pandian, Senthur
Relevance of Exhaust Aftertreatment System Degradation for EU7 Gasoline Engine Applications2020-01-03824/14/2020
Exhaust aftertreatment systems must function sufficiently over the full useful life of a vehicle. In Europe this is currently defined as 160.000 km. With the introduction of Euro 7 it is expected that the required mileage will be extended to 240.000 km. This will then be consistent with the US legislation. In order to quantify the emission impact of exhaust system degradation, an Euro 7 exhaust aftertreatment system is aged by different accelerated approaches: application of the Standard Bench Cycle, the ZDAKW cycle, a novel ash loading method and borderline aging. The results depict the impact of oil ash on the oxygen storage capacity. For tailpipe emissions, the maximum peak temperatures are the dominant aging factor. The cold start performance is effected by both, thermal degradation and ash accumulation. An evaluation of this emission increase requires appropriate benchmarks. For this purpose, an analysis of the emission impacts of ambient temperatures, driving modes and particulate filter regenerations follows. The comparison shows the severe impact of very low ambient conditions. Considering the high statistical relevance of catalyst degradation however, full useful life optimization requires special attention for Euro 7 gasoline engine applications.
Sterlepper, Stefan, Claßen, Johannes, Pischinger, Stefan, Görgen, Michael, Cox, Jim, Nijs, Martin, Scharf, Johannes
The Isochoric Engine2020-01-07964/14/2020
For the gasoline engine, the isochoric process is the ideal limit of the ideal processes. During the project, a combustion engine with real isochoric boundary conditions is built. A “resting time” of the piston for several degrees crank angle in the top dead center (TDC) can be realized with a special crank drive. This crank drive consists of two crankshafts with different strokes, which are combined. The two crankshafts rotate with a ratio of two to one in opposite directions. The total stroke corresponds to the amount of the first crankshaft, so it is possible to investigate different strokes of the second crankshaft in the same crankcase. Different “resting times” can be achieved by different strokes of the second crankshaft. A specific combination of both crankshafts make a stroke possible which corresponds to that of a conventional combustion engine. In addition to the standard cylinder pressure sensor, a quick surface temperature probe is also used as supplementary measurement technology. The influence of isochoric combustion is studied with constant air mass and constant lambda at three different strokes of the small crankshaft.
Burger, Benjamin, Bargende, Michael
Numerical Optimization of a SCR System Based on the Injection of Pure Gaseous Ammonia for the NOx Reduction in Light-Duty Diesel Engines2020-01-03564/14/2020
Selective Catalytic Reduction (SCR) systems are nowadays widely applied for the reduction of NOx emitted from Diesel engines. The typical process is based on the injection of aqueous urea in the exhaust gases before the SCR catalyst, which determines the production of the ammonia needed for the catalytic reduction of NOx. However, this technology is affected by two main limitations: a) the evaporation of the urea water solution (UWS) requires a sufficiently high temperature of the exhaust gases and b) the formation of solid deposits during the UWS evaporation is a frequent phenomenon which compromise the correct operation of the system. In this context, to overcome these issues, a technology based on the injection of gaseous ammonia has been recently proposed: in this case, ammonia is stored at the solid state in a cartridge containing a Strontium Chloride salt and it is desorbed by means of electrical heating. In this work, an after-treatment system based on the injection of gaseous ammonia in the SCR system is considered. Numerical 1D and 3D CFD simulations are applied in order to optimize the NOx reduction process. In particular, CFD methodology is applied to study in details the process of injection of the gaseous ammonia in the main exhaust gas stream and the effectiveness of the mixing process. Different geometrical layouts are compared to evaluate their performances in terms of uniformity of the NH3 distribution across the inlet section of the catalyst and pressure drop introduced in the exhaust line. Moreover, a 1D simulation tool is applied to evaluate the performances of the entire exhaust after-treatment system. The 1D model is calibrated on the basis of the information coming from detailed CFD simulations, in particular for what concerns the modeling of the effects of the different mixer geometries in terms on NH3 distribution. In this case, a simplified 3D catalyst is simulated, to take into account the maldistribution of ammonia at the inlet cross section and to evaluate its impact on the global deNOx performance of the system for different dosing strategies and for different levels of the ammonia maldistribution.
Della Torre, Augusto, Montenegro, Gianluca, Onorati, Angelo, Cerri, Tarcisio, Tronconi, Enrico, Nova, Isabella
Engine Order Sound Simulation by Active Sound Generation for Electric Vehicles10-04-02-00112/4/2020
In this article, an active sound generation (ASG) system is proposed to simulate engine order sound that is typically found in vehicles equipped with internal combustion engines. Based on an A-class electric SUV, a mathematical model simulating engine order sound is established, and a short-time Fourier transform and synthesis technique is implemented. An ASG hardware along with its main functional circuits is designed, and the control software is developed. The ASG system is configured based on the loudspeakers used by the vehicle’s audio system and the frequency response characteristics of the loudspeakers is obtained by testing. An interior sound design method simulating acceleration conditions is investigated in detail. The control method is formulated based on the interior noise characteristics in accordance with the engine order sound amplitude variation. By establishing a design process with an ASG calibration and evaluation method, the accuracy of the acoustic synthetic method is validated. In summary, this work provides an interior sound design process to simulate accelerating conditions for electric vehicles and has established a sound control, calibration, and evaluation methodology for ASG systems.
Cao, Yuntao, Hou, Hangsheng, Liu, Yingjie, Tang, Lechao, Li, Yun
Sound Quality Development Using Psychoacoustic Parameters with Special Focus on Powertrain Noise2020-01-50001/24/2020
This research uses vehicle interior noise at the driver position during full load acceleration to objectively define the resultant Sound Quality (SQ) of the vehicle analyzed by focusing on powertrain noise. A calculation method is developed to rank vehicles in order of customer preference (Sound Rank) and provide a subjective evaluation score for different error states a vehicle can encounter. In order to calculate these two scores, a pleasantness parameter is obtained using standard calculated psychoacoustic parameters with different weighting scores depending on their importance toward the preference ranking. Then pleasantness is correlated with jury test results and subjective evaluations. The results obtained show that the model is capable of quantifying the vehicle SQ during the vehicle development process and position a vehicle within a two-dimensional (2D) powerful-refined plot. This is achieved with the help of psychoacoustic parameter scatter bands. The model provides an objective tool to quantify and verify the resultant SQ to help meet and optimize Noise, Vibration, and Harshness (NVH) targets.
Victor, Garanto, Zhirong, Geng, Junfeng, Hu, Xiaolong, Deng, Wanli, Yang, Hao, Wang
Effects of Stepped-Lip Combustion System Design and Operating Parameters on Turbulent Flow Evolution in a Diesel Engine03-13-02-00161/16/2020
Interactions between fuel sprays and stepped-lip diesel piston bowls can produce turbulent flow structures that improve efficiency and emissions, but the underlying mechanisms are not well understood. Recent experimental and simulation efforts provide evidence that increased efficiency and reduced smoke emissions coincide with the formation of long-lived, energetic vortices during the mixing-controlled portion of the combustion event. These vortices are believed to promote fuel-air mixing, increase heat-release rates, and improve air utilization, but they become weaker as main injection timing is advanced nearer to the top dead center (TDC). Further efficiency and emissions benefits may be realized if vortex formation can be strengthened for near-TDC injections. This work presents a simulation-based analysis of turbulent flow evolution within a stepped-lip combustion chamber. A conceptual model summarizes key processes in the evolution of turbulent flow for main injections starting after TDC. Differences in turbulent flow evolution are described for a near-TDC main injection, and potential variations in combustion system design and operating parameters to enhance vortex formation under these conditions are hypothesized. The parametric studies executed to test these hypotheses reveal that while intake pressure and spray targeting play important roles in turbulent flow evolution, they are not capable of fundamentally changing the late-cycle flow topology for near-TDC injection timings. A dimpled stepped-lip (DSL) piston design is developed that supports the hypothesis that increasing space in the squish region promotes vortex formation for near-TDC injection timings. Further analyses reveal the mechanisms by which the DSL piston strengthens vortex formation.
Busch, Stephen, Perini, Federico, Reitz, Rolf, Kurtz, Eric
Variable Camshaft Valve Timing and its Effects to Hydrous Ethanol (E100) Combustion during Engine Warm up Phase2019-36-01471/13/2020
In-cylinder airflow has significant impact in mixture formation and burn in internal combustion engines. Exhaust valve closing retard and early intake valve opening have large contribution for the in-cylinder airflow. It may reduce pumping work (energy lost to pump exhaust gases out of the cylinder and to draw the fresh air-fuel mixture), hurt combustion stability due to the excess of residual gas in the combustion chamber or still contribute to cylinder scavenging, increasing the amount of fresh air resulting in higher burn efficiency and more work extracted from the cycle. Brazilian market has large Hydrous Ethanol fuel (E100) usage. Due to E100 fuel properties, the intake and exhaust valves opening and closing time must be carefully defined during the engine warm up phase to avoid negative effects on the combustion. The objective of this work is to analyze the effects in performance, combustion stability and emissions, of exhaust valve timing at different engine temperatures when using E100 fuel in a Ford 1.5L naturally aspirated 3-cylinder engine with Port Fuel Injection (PFI) and dual variable valve timing control. The study shows that it is possible to obtain significant emissions improvements during warm up phase by optimizing exhaust valve timing, without exceeding combustion stability limits.
Passarini, Gustavo C., Fregoneze, Marcos, Júnior, Fernando Sarracini
Engine calibration and driveability evaluation of a racecar2019-36-01261/13/2020
The passenger car automakers are always competing to excel in vehicle characteristics related to passenger comfort and driveability aspects. The engine calibration is a theoretical and experimental procedure with the intention to extract maximum efficiency from the engine and guarantee satisfactory levels of driving for both conventional and racing cars. This paper describes the calibration procedure of a Formula SAE race car engine. The engine was a four cylinder 600 cm3 four-strokes with modified intake and exhaust systems, controlled by an engine control unit (Motec M800 ECU). These engines present optimized characteristics for high speed, in exchange for some combustion degradation in some specific operating conditions at low speed that may impair vehicle driveability. Therefore, good tip-in reaction and the progression of the torque delivery are fundamental criteria to increase the vehicle performance, specially, to those submitted to short acceleration distances. The related criteria to the vehicle dynamic comfort has objective values to measure the abrupt engine speed transactions, jerks and acceleration variability related to torque variation. Improvement on such parameters can be obtained by means of main factors that influence in the combustion such as the air/fuel ratio control and the spark timing. In reality, the variations or instabilities in the torque delivery can be verified by analyzing instabilities in engine speed. This paper describes the direct approach with the aim of reducing temporal engine speed variability and compare it to the driveability criteria. Thus, accelerometers were used to quantify the vehicle longitudinal accelerations, decelerations and critical track conditions, such as low speed traction, to evaluate the engine calibration and correlate data in favor of the driveability and performance improvements.
Goulart, Aleff, Piccini, Alexandre, Müller, Alice, Balbom, Felipe, Martins, Mario, Carvalho, Pedro
Injection Strategies for Isobaric Combustion2019-01-226712/19/2019
In a previous study, we demonstrated that the isobaric combustion cycle, achieved with a split injection strategy, can be more suitable for the double compression expansion engine concept than the conventional diesel combustion cycle. The present work is focused on understanding the effect of different injection strategies on the heat release, efficiency, and emissions of isobaric combustion at the peak cylinder pressure of 150 bar. In situ injection rate measurements are performed to improve our understanding of the heat release rate shape and pollutant formation. A variation of load is performed to demonstrate the feasibility of the isobaric combustion cycle at higher loads, and the means of achieving them. The thermal efficiency reduces at lower loads because of heat losses. It peaks at a medium load point before reducing again at higher loads because of exhaust losses. The effect of altering the injection strategy on the isobaric combustion cycle is also studied at a constant equivalence ratio. The alteration of injection strategy is proven to have minimal effect on efficiency, loss mechanisms, and emissions when more than one injection is used.
Babayev, Rafig, Houidi, Moez Ben, Shankar, VS Bhavani, Aljohani, Bassam, Johansson, Bengt
Scavenging Phenomena Based Post-oxidation in Exhaust Manifold of a Turbocharged Spark Ignition Engine2019-01-219712/19/2019
In this research, a novel methodology for the post-oxidation in a turbocharged spark ignition (SI) engine is proposed and investigated that can improve the emissions along with the reduction in turbo-lag. In this research, both simulation and experimental activities are performed. The 1-D simulation model was used for the identification of efficient scavenging. Thereafter, experimental validation tests for modeling and post oxidation were conducted on a 4-cylinder turbocharged SI engine. From the results, it was revealed that efficient scavenging and post-oxidation can be obtained at lower speed and higher load. The enthalpy in exhaust manifold increased due to the post-oxidation reaction which in turn increased the temperature and pressure of the exhaust gases and hence emissions reduced. Also, due to the increased enthalpy at turbine upstream, the turbocharger speed increased and as a consequence, reduction in the turbo-lag was observed. It was also noted that the post-oxidation is limited at higher load and overlap in an inline 4-cylinder engine due to the strong scavenging which increased the cooling effect in in-cylinder and exhaust manifold due to excess air.
Kumar, Madan, Kuboyama, Tatsuya, Hasegawa, Naohiro, Moriyoshi, Yasuo
Research of the High Altitude Control Strategy of the Piston Aero-engine Using Two-stage Turbocharger Coupled with single Supercharging System2019-01-221112/19/2019
Aiming at the high altitude operation problems for piston-type aero-engines and to improve the practical ceiling and high altitude dynamic performance, this thesis analyzes a controllable three-stage composite supercharging system, using a two-stage turbocharger coupled supercharger method. The GT-Power simulation model of a four-cylinder boxer engine was established, and the control strategy of variable flight height was obtained. The simulation research of engine performance from 0 to 20,000 meters above sea level has been carried out, which shows that the engine power is at the same level as the plain condition, and it could still maintain 85.28 percent of power even at the height of 20,000 meters, which meets the flight requirements of the aircraft.
Yao, Ye, Shi, Lei, Zhang, Zhe, Xiao, Maoyu, Liu, Mingwei, Tan, Jianwei
Online Automatic Adaptation for Model-based Control of Diesel Engine2019-01-232012/11/2019
In this paper, an online automatic adaptation method for model-based control of a diesel engine is developed. Control-oriented models based on physics has been proposed as substitutes for conventional control methods to improve the performance of engine under real driving situation. Even such physical-rich models have fitting parameters and it is preferable to adapt the parameters according to the real-time operating condition. Therefore, an automatic adaptation method for the model is developed, and the method is based on neural network. The prediction accuracy of the model is evaluated by simulation and it is confirmed that the method can be applied online to a real engine by experiment.
CAO, Jianan, TAKAHASHI, Motoki, YAMASAKI, Yudai, KANEKO, Shigehiko
Combustion Optimization and In-Cylinder NOx and PM Reduction by Using EGR and Split Injection Techniques2019-28-256011/21/2019
Nowadays, the major most challenge in the diesel engine is the oxides of nitrogen (NOx) and particulate matter (PM) trade-off, with minimal reduction in Power and BSFC. Modern day engines also rely on expensive after-treatment devices, which may decrease the performance and increase the BSFC. In this paper, combustion optimization and in-cylinder emission control by introducing the Split injection technique along with EGR is carried out by 1-D (GT- POWER) simulation. Experiments were conducted on a 3.5 kW Single-cylinder naturally aspirated CRDI engine at the different load conditions. The Simulation model incorporates detailed pressure (Burn rate) analysis for different cases and various aspects of ignition delay, premixed and mixing controlled combustion rate, the injection rate affecting oxides of nitrogen and particulate matter. The predictive combustion model (DI-PULSE) has been developed for the calibration of an engine under multiple injections and the detailed injection rates with EGR rates. Split injection with higher fuel quantity injected in the 1st pulse, helped to significantly reduce PM emissions. This reduction is due to the restraint in the premixed phase of the 2nd pulse combustion. Split injections technique is helpful to effectively reduce NOx as well as PM emissions, as compared to increasing dilution rates and injection pressure (700 to 1000 bar) using Cooled EGR and retarding the injection timing. It is noted that for a case of 60(10)40 retarded to injection timings of 20°bTDC, 18°bTDC and 16°bTDC from 23°bTDC has resulted in 31.32% reductions in soot emissions and 38.23% reduction in NOx emissions. Results showing that the simultaneous reduction in NOx emissions and PM emissions is possible with an optimized combination of Split injections & the EGR, under different load conditions and the experimental values are almost matching with the 1-D simulation.
Kumar, Madhan, Jain, Aatmesh, Chhaganlal Vora, Kamalkishore
Engine Valve Train Dynamic Analysis using 1-D Simulation Approach2019-28-242211/21/2019
In order to reduce engine development timing and cost, a numerical calculation used to evaluate valve train systems. This paper discusses the work done on kinematic and dynamic analysis of Valve Train (VT) system of a diesel engine by using 1-D Ricardo Valdyn software. The goal is to meet optimum intake, exhaust valve timing requirement, maximize, valve open area and 30% over-speed requirement. Valve train model is prepared and inputs like mass and stiffness are estimated from 3-D model and finite element analysis, respectively. Simulation model is used for predicting valve bounce speed, valve displacement, cam-follower contact stress and strain in the rocker arm. Initially, Kinematic analysis is carried out to study the change in valve motion characteristics such as cam contour radius, tappet contact eccentricity etc. Further to this, dynamic analysis is carried out to assess forces and stresses on valve train components. Effect of cam tappet contact stresses, buckling load on push rod, spring surge, ratio of spring force to inertia force, valve seating velocity at increased speed condition etc. are discussed in detail. The optimized cam profile and ramp have improved overall valve dynamics in terms of valve seating velocity and valve seating force. The dynamic vibration described in this paper has been fully validated by measurement.
Nain, Ajay, Nene, Devendra
Potential for Emission Reduction and Fuel Economy with Micro & Mild HEV2019-28-250411/21/2019
The development of modern combustion engines (spark ignition as well as compression ignition) for vehicles compliant with future oriented emission legislation (BS6, Euro VI, China 6) has introduced several technologies for improvement of both fuel efficiency as well as low emissions combustion strategies. Some of these technologies as there are high pressure multiple injection systems or sophisticated exhaust gas after treatment system imply substantial increase in test and calibration time as well as equipment cost. With the introduction of 48V systems for hybridization a cost- efficient enhancement and, partially, an even attractive alternative is now available. An overview will be given on current technologies as well as on implemented test procedures. The focus will be on solutions which have potential for the Indian market, i.e. solutions which can be implemented with moderate application effort for currently available compact and medium size cars. The possibilities of 48V technologies for fuel economy and emission reduction will be discussed. Simultaneously, tools for testing and calibration at power train testbed as well as for on-road application will be presented. Furthermore, it considers the requirements on the test procedures due to the transition from NEDC to WLTP and the implications of the demand for greater integration of tests under real driving conditions (RDE).
Murr, Franz, Winklhofer, Ernst, Weissbaeck, Michael, Teuschl, Gerald
More sting for the STINGRAY19AUTP11_0211/1/2019
GM Propulsion engineers elevate the evergreen small-block V8 to new heights for its mid-engine Corvette mission. Instead of heaving decades of small-block V8 expertise out the window, GM Propulsion engineers led by chief engineer Jordan Lee leveraged past success to create a new-for-2020 V8. Known as the LT2, the 6.2-L V8 gives Chevy's all-new, eighth-generation 2020 Corvette more power (the most yet in the base Stingray), stirring response, and competitive fuel efficiency compared with the outgoing C7. And the small-block, with its single camshaft in block and two valves per cylinder, remains unmatched versus its rivals in three key metrics: bill of material, package efficiency, and the power-per-dollar quotient. It's the payoff for 65 years of continuously refining (and never giving up on) a brilliant original design.
Sherman, Don
Design, Development and Analysis of Mullite Catalytic Converter for CI Engines2019-28-001710/11/2019
Emissions of Hydrocarbon (HC), Carbon Monoxide (CO) and Oxides of Nitrogen (NOx) are the largest concerns for fossil fuel driven automotive vehicles. Catalytic converter is an important component in the selective catalytic reduction process. It oxidizes harmful CO and HC emission to CO2 and H2O in the exhaust system and thus the emission is controlled. Different kinds of problems are associated with noble metal based catalytic converter. A catalytic converter with a new catalyst for compression ignition engine is considered in this study. The catalytic converter is designed and developed with a new catalyst. Due to better durable characteristics and poison resistant nature, non-noble metal based material limestone (mullite) is selected as a catalyst for catalytic convertor and the emission characteristics are studied on four stroke single cylinder CI engine by using mullite based catalytic converter. The results are compared without catalytic converter in the same engine. In the design stage, the back pressure analysis is performed on perforated mullite plate with ANSYS software. After arriving satisfactory results, the design is taken for development. The developed catalytic converter is tested on a single cylinder DI diesel engine coupled with dynamometer under variable engine running conditions. Though not a noble metal, limestone works as a catalyst for reduction of HC, CO and NOx emissions. It is therefore concluded that a simple low-cost limestone based catalytic converter can be thought as an alternative for expensive noble metal based converters.
Pandiaraj, Selvakumar, Subbaiyan, Dhamotharan, Ayyasamy, Tamilvanan, Nagarajan, Sathishkumar
Maintenance of Design Voltage - Snowmobile Electrical SystemsJ277_201909 (Current)9/25/2019
This SAE Recommended Practice provides test methods and requirements for maintenance of design voltage in snowmobile electrical systems. It pertains to both battery-equipped and battery-less systems.
Snowmobile Technical Committee
Analysis of TWC Characteristics in a Euro6 Gasoline Light Duty Vehicle2019-24-01629/9/2019
A Euro6 gasoline light duty vehicle has been tested at the engine dynamometer and the emissions have been analyzed upstream and downstream the Three-Way-Catalyst (TWC) during a WLTC cycle. Catalyst simulations have been used for assessing the processes inside the catalytic converter using a reaction scheme based on 19 brutto reactions (direct oxidation and reduction, selective catalytic reductions with CO, C3H6 and H2, steam reforming, water-gas shift and bulk ceria as well as surface ceria reactions). The reactions have been parameterized in order to best approximate the measurements. Based on the reactions taken into account, the real vehicle emissions can be predicted with good accuracy. The simulations show that the cycle emissions comprise mainly the cold start contribution as well as discrete emission break-through events during transients. During cold start no reactions are evident in the catalyst before the temperature of the gas entering the catalyst reaches 270°C. Following the light-off, prevailing reactions are direct oxidation as well as surface ceria reactions for CO and THC. NO reduction during cold start is due to reaction with CO as well as due to surface ceria. During warm engine operation, CO break-throughs during transients are mainly due to lack of oxygen following short periods where the engine lambda drops below one and most of surface and bulk CeO2 has reacted to surface and bulk Ce2O3. Moreover in such incidents ceria is reacting with THC forming additional CO. THC break-throughs during transients are mostly simultaneous with CO peaks and are also due to lack of oxygen and depleted CeO2. NO transient break-throughs occur when engine-out NO sharply increases, and the reactions with CO and ceria are not sufficient. Further analysis focused in highlighting the effects of variations of Lambda and precious metal content on reaction emissions and mechanisms.
Papetti, Viola, Dimopoulos Eggenschwiler, Panayotis, Emmanouil, Vasiliki, Koltsakis, Grigorios
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
Development of a Hybrid Power Unit for Formula SAE Application: ICE CFD-1D Optimization and Vehicle Lap Simulation2019-24-02009/9/2019
The paper reviews the CFD optimization of a motorcycle engine, modified for the development of a hybrid powertrain of a Formula SAE car. In a parallel paper, the choice of the donor engine (Ducati 959 Panigale: 2-cylinder, V90, 955 cc, peak power 150 HP at 10500 rpm, peak torque 102 Nm at 9000 rpm) is thoroughly discussed, along with all the hardware modifications oriented to minimize the new powertrain dimensions, weight and cost, and guarantee full reliability in racing conditions. In the current paper, the attention is focused on two main topics: 1) CFD-1D tuning of the modified Internal Combustion Engine (ICE), in order to comply with the Formula SAE regulations, as well as to maximize the power output; 2) simulation of the vehicle in racing conditions, comparison with a conventional combustion car and a full electric vehicle. The stock engine has been strongly modified, since the head of the vertical cylinder has been replaced by the electric motor, and the intake system of the other cylinder now includes a 20 mm restrictor. Despite these constraints, the tuned ICE is able to deliver more than 70 HP. Finally, the study shows that the hybrid car is not only more efficient (-26% of specific CO2), but also 1.48 s faster on each lap than the corresponding Combustion single seater.
Mattarelli, Enrico, Rinaldini, Carlo Alberto, Scrignoli, Francesco, Mangeruga, Valerio
Modeling of a Spark Ignition Engine with Turbo-Generator for Energy Recovery2019-24-00849/9/2019
Increasingly stringent regulations in the field of pollutant are forcing engine manufacturers to adopt new solutions to contain exhaust emissions, such as Hybrid Electric Vehicles (HEV) or Full Electric Vehicles (FEV). Still far from the wide diffusion of FEV limited from electrochemical storage systems together with the difficulty of creating adequate infrastructure distributed throughout the territory to recharging batteries, the HEV seems to be actually a better solution. The hybrid vehicle is already able to guarantee satisfactory autonomy and low pollution levels by combining the advantages offered by the two technologies of thermal and electric propulsion. Currently on the market there are several types of hybrid vehicles, with different degree of hybridization (electric motor power versus propulsion total power), capacity to store electricity and type of scheme constructive adopted for the integration between the thermal engine and the electric machine. A particular interest is getting the mild-hybrid (or light hybridization) and the micro-hybrid (or minimum hybridization) with 48V electrical system added to the classic 12V one. A possible solution could be the electric turbo-compounding system where a turbine coupled to a generator (turbo-generator) uses the exhaust gas flow of a reciprocating engine to harvest waste heat energy and convert it into electrical power. In this way, the power generated from the system can be used to feed local electrical loads such as engine auxiliaries, increasing the whole system efficiency. The present study deals with the simulation of a spark ignition engine, present in a test room of Istituto Motori (CNR), including a turbo-generator at the exhaust to evaluate the advantages in terms of overall efficiency. The internal combustion engine model was developed by using a 1D code (GT-Power software), while the turbo-generator and the electric system are described in the Matlab/Simulink environment. The results obtained showed an appreciable increase in the overall efficiency.
Arminio, Fabio, Cameretti, Maria Cristina, De Simio, Luigi, Iannaccone, Sabato, Terzo, Teodoro
The Ultra Low Emissions Potential of the Recuperated Split Cycle Combustion System2019-24-01899/9/2019
The recuperated split cycle engine is a fundamentally new class of internal combustion engine that offers a step change in thermal efficiency over conventional Otto and Diesel cycle engines. In a split cycle engine, the compression and combustion strokes are performed in different cylinders. Intensive cooling of the compression stroke by the injection of liquid nitrogen directly into the chamber enables the recovery of waste heat from the exhaust between the compression and combustion cylinders. Brake efficiencies of over 50% have been reported without compression cooling, rising to 60% where the compression stroke is cooled by the injection of liquid nitrogen. The technology targets the heavy duty, long-haul sector where electrification is ineffective. In this paper, results from an experimental program conducted on a single cylinder research engine, representing the combustor cylinder of a recuperated split cycle engine are reported. The effect of fuel injection timing, valve timing and injection pressure were studied at 1200rpm at a range of loads. Experiments using oxygen depleted air to represent the effect of the injection of liquid nitrogen in the compression cylinder are also reported. Engine out NOx emissions of less than 110ppm at mid speed and loads typical of motorway cruise conditions for a truck engine were observed. The low NOx emissions suggest a significant contribution of cool, pre-mixed combustion. A conceptual modeling is proposed that describes the mixing process inside the combustion chamber to explain the low NOx emissions. It is proposed an air jet is formed during the induction of charge air which interacts with the liquid fuel jet, enhancing mixing. This together with the lower charge temperatures used account for the low NOx emissions. The impact of fitting an SCR based aftertreatment catalyst on final vehicle emissions is presented, demonstrating the potential of achieving very low levels of NOx emissions. With aftertreatment, NOx emissions below 5ppm were predicted, meaning the recuperated split cycle engine has the potential of meeting the SULEV NOx standard.
Morgan, Robert, Lenartowicz, Christopher, Vogiatzaki, Konstantina, Harvey, Simon, Kennaird, David, Owen, Nicholas, Pickett, Rhys, Atkins, Andrew
Intake Manifold Primary Trumpet Tuning Options for Fuel Flow Limited High Performance I.C.E.2019-24-00059/9/2019
The 2014 change in Formula One regulations, from naturally aspirated to highly-downsized and heavily-boosted hybridized power units, led to a relevant increase of the internal combustion engine brake specific power output in comparison with former V-8 units. The newly designed “down-sized” engines are characterized by a fuel flow limitation and a relevant increase in the thermal loads acting on the engine components, in particular on those facing the combustion chamber. Furthermore, efficiency becomes an equivalent paradigm as performance. In the power unit layout, the air path is defined by the compressor, the intercooler and the piping from the intake plenum to the cylinder. Intake duct length is defined from intake plenum to valve seat and it is a key parameter for engine performance. In order to find the optimum length different design criteria can be applied: the so called “tuning”, the “un-tuning” or the “anti-tuning” are all valid possibilities, showing pros and cons. The scope of the paper is to study and present the possible different tuning options for the internal combustion engine (ICE) part of a hybrid F1 powertrain. From 2015, variable trumpet can be used: the continuous variable length may be used to optimize volumetric efficiency and furthermore to reduce knocking and improve combustion accordingly. The scope of the paper is to show and qualitatively compare all the different options for a hybrid powertrain with fuel flow limited combustion unit.
Rosetti, Angelo, Iotti, Corrado, Cantore, Giuseppe
Definition of a Methodology Promoting the Use of 1D Thermo-Fluid Dynamic Analysis for the Reduction of the Experimental Effort in Engine Base Calibration2019-24-00139/9/2019
Over the last decades, internal combustion engines have undergone a continuous evolution to achieve better performance, lower pollutant emissions and reduced fuel consumption. The pursuit of these often-conflicting goals involved changes in engine architecture in order to carry out advanced management strategies. Therefore, Variable Valve Actuation, Exhaust Gas Recirculation, Gasoline Direct Injection, turbocharging and powertrain hybridization have found wide application in the automotive field. However, the effective management of a such complex system is due to the contemporaneous development of the on-board Engine electronic Control Unit. In fact, the additional degrees of freedom available for the engine regulation highly increased the complexity of engine control and management, resulting in a very expensive and long calibration process. To overcome these drawbacks, an effective methodology based on the adoption of 1D thermo-fluid dynamic analysis is proposed in this study. In particular, starting from a complete experimental set of data actually used for the base calibration of a reference spark ignition engine, a novel procedure based on vector optimization approach is used to reliably calibrate a 1D engine model starting from a reduced experimental dataset. Once validated, the engine model is then used as a virtual test bench to reproduce the experimental campaign numerically, thus obtaining a detailed and complete dataset exploitable for calibration purposes, here called numerical or virtual dataset. To verify the potential of the proposed methodology, experimental and virtual dataset have been finally compared. The research clearly demonstrates the effectiveness of the proposed approach since the average errors are comparable with the measurement errors. Therefore, the methodology shows promising results concerning the use of numerical dataset obtained from reliable 1D CFD engine models as input to computer aided calibration software. This way, a significant cut to the experimental campaign required for calibration purposes is achieved, with their related times and costs.
de Nola, Francesco, Giardiello, Giovanni, Gimelli, Alfredo, Molteni, Andrea, Muccillo, Massimiliano, Tortora lng, Roberto
Virtual Investigation of Real Fuels by Means of 3D-CFD Engine Simulations2019-24-00909/9/2019
The reduction of both harmful emissions (CO, HC, NOx, etc.) and gases responsible for greenhouse effects (especially CO2) are mandatory aspects to be considered in the development process of any kind of propulsion concept. Focusing on ICEs, the main development topics are today not only the reduction of harmful emissions, increase of thermodynamic efficiency, etc. but also the decarbonization of fuels which offers the highest potential for the reduction of CO2 emissions. Accordingly, the development of future ICEs will be closely linked to the development of CO2 neutral fuels (e.g. biofuels and e-fuels) as they will be part of a common development process. This implies an increase in development complexity, which needs the support of engine simulations. In this work, the virtual modeling of real fuel behavior is addressed to improve current simulation capabilities in studying how a specific composition can affect the engine performance. The goal is to create a series of models that allow to virtually investigate different fuels and to minimize, as much as possible, the costly and time-consuming experimental tests. In the first part, a fuel modeling approach is presented and compared with traditional methodologies. Subsequently, two fuel virtual investigations are presented. In the first, fuels with different RON and oxygenates content are compared to analyze their knock behavior and performance potential. In the second analysis, the fuel investigation - conducted virtually at the FKFS of Stuttgart and experimentally at the engine laboratory of the Chair of Internal Combustion Engines at the Technical University of Munich with the support from Volkswagen Motorsport GmbH - on a single-cylinder research engine operating with the innovative SACI (Spark Assisted Compression Ignition) combustion concept is presented.
Cupo, Francesco, Chiodi, Marco, Bargende, Michael, Koch, Daniel, Wachtmeister, Georg, Wichelhaus, Donatus
Ultra-Lean Pre-Chamber Gasoline Engine for Future Hybrid Powertrains2019-24-01049/9/2019
Lean burn gasoline spark-ignition engines can support the reduction of CO2 emissions for future hybrid passenger cars. Very high efficiencies and very low NOx raw emissions can be achieved, if relative air/fuel ratios λ of 2 and above can be reached. The biggest challenge here is to assure a reliable ignition process and to enhance the fuel oxidation in order to achieve a short burn duration and a good combustion stability. This article aims at introducing an innovative combustion system fully optimized for ultra-lean operation and very high efficiency. Thereto, a new cylinder head concept has been realized with high peak firing pressure capability and with a low surface-to-volume ratio at high compression ratios. 1D and 3D simulations have been performed to optimize the compression ratio, charge motion and intake valve lift. Numerical calculations also supported the development of the ignition system. Stable ignition and fast flame propagation were achieved thanks to a centrally located active pre-chamber which allows to control the air/fuel ratio independently of the air/fuel ratio in the main combustion chamber. Experimental investigations have then been performed with a single cylinder engine to demonstrate the capabilities of this new combustion system in a sweet spot operating point. A maximal indicated thermal efficiency of 47% was achieved at λ = 2 with optimized injection settings in the pre and main combustion chambers. The fuel efficiency could be maximized thanks to a fast and knock-free combustion process. Compared to the reference operation with stoichiometric air/fuel ratio, only a seventieth of the NOx raw emissions were measured (i. e. 50 ppm), and the particulate mass emissions were halved. The energy balance analysis points out that these promising results could be further improved by working on the reduction of the unburnt hydrocarbon emissions and by jointly optimizing the scavenging process.
Serrano, David, Zaccardi, Jean-Marc, Müller, Christoph, Libert, Cedric, Habermann, Knut
Design of a Hybrid Power Unit for Formula SAE Application: Packaging Optimization and Thermomechanical Design of the Electric Motor Case2019-24-01979/9/2019
This paper presents the development of a parallel hybrid power unit for Formula SAE application. In particular, the system is made up of a brand new, single-cylinder 480 cc internal combustion engine developed on the basis of the Ducati “959 Superquadro” V90 2-cylinders engine. The thermal engine is assisted by a custom electric motor (30 kW), powered by a Li-Ion battery pack. The performance of the ICE has been optimized through CFD-1D simulation (a review of this activity is reported in a parallel paper). The main design goal is to get the maximum amount of mechanical energy from the fuel, considering the car typical usage: racing on a windy track. The Ducati “959 Superquadro” engine is chosen because of its high power-to-weight ratio, as well as for its V90 2-cylinder layout. In fact, the vertical engine head is removed and it is subsequently replaced by the electric motor directly engaged to the crankshaft using the original valvetrain transmission chain, thus achieving a very compact package. The mechanical behaviour of the original chain is investigated for this purpose. A specific electric motor case is then designed and manufactured via Additive Manufacturing technology, in order to include the chain housing, the electric motor cooling system and the lubrication system. Furthermore, the case flange is designed to perfectly fit to the original engine deck in order to allow the engine cooling circuit to match with the electric motor cooling circuit. Several types of circuit layout - around the stator - are analysed via CFD simulations comparing pressure drop and heat transfer coefficients. Finally, a thermo-structural analysis is performed in order to assess the mechanical strength of the electric motor case.
Mangeruga, Valerio, Giacopini, Matteo, Barbieri, Saverio Giulio, Berni, Fabio, Mattarelli, Enrico, Rinaldini, Carlo
Analysis of Water Injection Strategies to Exploit the Thermodynamic Effects of Water in Gasoline Engines by Means of a 3D-CFD Virtual Test Bench2019-24-01029/9/2019
CO2 emission constraints taking effect from 2020 lead to further investigations of technologies to lower knock sensitivity of gasoline engines, main limiting factor to increase engine efficiency and thus reduce fuel consumption. Moreover the RDE cycle demands for higher power operation, where fuel enrichment is needed for component protection. To achieve high efficiency, the engine should be run at stoichiometric conditions in order to have better emission control and reduce fuel consumption. Among others, water injection is a promising technology to improve engine combustion efficiency, by mainly reducing knock sensitivity and to keep high conversion rates of the TWC over the whole engine map. The comprehension of multiple thermodynamic effects of water injection through 3D-CFD simulations and their exploitation to enhance the engine combustion efficiency is the main purpose of the analysis. As basis for the research a single cylinder engine derived from a 1l turbocharged 3-cylinders engine is used to evaluate indirect and direct water injection. The entire engine flow field is reproduced and analyzed with 3D-CFD simulations and numerical models are employed to separate the influence of chemical and thermodynamic properties. Measurements are performed with different injectors for indirect/direct water injection in the single-cylinder engine in order to assess water break-up, wall wetting, spray interaction and penetration. Several injection strategies, such as varying start of injection, injection pressure, and water to fuel ratio, are tested at the single-cylinder engine test bench. Detailed gas phase chemistry is employed to link flame front speed with water concentration and knocking occurrence. These results are correlated with the 3D-CFD simulation of mixture formation, in-cylinder flow and water distribution for two different operating points (part load and maximum power) in order to study water behavior, with focus on the evaporation process, in-cylinder pressure and temperature profile, as well as the combustion development, during multiple engine cycles.
Vacca, Antonino, Bargende, Michael, Chiodi, Marco, Franken, Tim, Netzer, Corinna, Gern, Maike Sophie, Kauf, Malte, Kulzer, André Casal
Back-Pressure and Fuel Type Effects on Exhaust Gas Oxygen Sensor Readings for a Single Cylinder Spark Ignition Engine Running on Gasoline and Ethanol2019-24-00469/9/2019
Application of more and more complex control strategies in spark ignition (SI) engines is required for ensuring high conversion efficiency and effective emissions reduction. Closed loop fuel injection is being implemented on an ever wider scale in small size SI units that generally feature single cylinder architecture. For such systems the readings from the exhaust gas oxygen sensor are essential for controlling air-fuel ratio and indirectly combustion. The present study looked at the influence of pressure oscillations on the values given by the sensor, for different equivalence ratio settings in wide open throttle conditions for an experimental SI unit. As expected, the readings were found to be influenced by pressure oscillations in the exhaust line during lean operation, while with stoichiometric and rich fueling the effects were minimal. Fuel type was also found to be an important aspect. Gasoline was compared to ethanol, and the latter underlined the effect of combustion efficiency on how the sensor readings need to be interpreted. Quasi-dimensional simulation using the GT-Power software was also used to provide further insight into the correlation between combustion phenomena and read air-fuel ratio. Following the combined experimental and numerical approach, the bases were put for defining an algorithm capable of compensating the effects of pressure oscillations without the need for an additional sensor.
Irimescu, Adrian
Engineering the 2020 CHEVROLET CORVETTE19AUTP09_019/1/2019
The eighth-gen (C8) Corvette is a creative mix of novel and traditional technical solutions unleashed at a shockingly low base price. Two days before the 50th anniversary of astronaut Neil Armstrong's leap for mankind and 10 years after General Motors emerged from bankruptcy, the camouflage was finally ripped from the eighth-generation (C8) 2020 Chevrolet Corvette. As widely anticipated, C8 now flaunts a mid-engine layout that ostensibly puts it on equal terms with the world's most venerated supercars. After six decades of experimentation and concept-car teasing, GM acknowledged that the new Stingray will enter production before year's end. The truly shocking announcement is a base price of $59,995 including destination, only $3,000 more than today's front-engine C7. Along with moving the cockpit forward 16.5 inches (419 mm) to facilitate shifting the engine rearward, the new Corvette is an innovative mix of novel and traditional engineering solutions.
Sherman, Don
Numerical Study of Pore Size and Distribution Effects on Gasoline Particulate Filter Performance03-12-05-00328/22/2019
Abstract The improved brake thermal efficiency of Gasoline Direct Injection (GDI) engines is accompanied by a significant increase in Particulate Matter (PM) mass and higher Particulate Number (PN) emissions as compared to (multi)Port Fuel Injected (PFI) engines. Gasoline particulate filters (GPFs) with high filtration efficiency and low backpressure will be required to meet the future, stringent PM/PN regulations. A two-dimensional (2D) CFD study was performed to determine the effects of pore size and distribution on the interdependent performance parameters of filtration efficiency and backpressure for clean GPFs. Simulation results show an on linear change infiltration efficiency as the pore size distribution tightens and determine a recommended distribution range, controlling the quantity of small-sized pores. Pore size distributions beyond this recommended range can cause a filtration performance loss or intolerable backpressure penalty for the GPF. In addition, a recent collaborative publication from our group has demonstrated our ability to create a hierarchical porous filter, with variable pore size in each layer. Knowing that filtration efficiency and pressure drop increase as the average pore size decreases offers inspiration for a novel wall design with small pores comprising the top 40% of the wall layers and larger pores on bottom 60%. The model predicts that such a wall would result in an 8% increase in filtration efficiency.
Yang, Pengze, Strzelec, Andrea
ELECTRIC MACHINES find their niche19TOFHP08_018/1/2019
Smaller machines working in cities are particularly ripe for electrification, but most off-highway applications will retain the internal-combustion engine. Many players in the off-highway market are announcing electrification efforts. But why? To date, global regulatory programs have spurred off-highway technological innovations, to improve fuel economy and reduce criteria pollutants. Think U.S. Tier 4 final, Euro Stage V and other global regulations. There's more to it now.
Morey, Bruce
A New Approach for Development of a High-Performance Intake Manifold for a Single-Cylinder Engine Used in Formula SAE Application03-12-04-00277/26/2019
The Formula SAE (FSAE) is an international engineering competition where a Formula style race car is designed and built by students from worldwide universities. According to FSAE regulation, an air restrictor with circular cross section of 20 mm for gasoline-fuelled and 19 mm for E-85-fuelled vehicles is to be incorporated between the throttle valve and engine inlet. The sole purpose of this regulation is to limit the airflow to the engine used. The only sequence allowed is throttle valve, restrictor and engine inlet. A new approach of combining Ram theory and acoustic theory methods are investigated to increase the performance of the engine by designing an optimized intake runner for a particular engine speed range and an optimized plenum volume in this range. Engine performance characteristics such as brake power, brake torque and volumetric efficiency are taken into considerations. Ricardo WAVE simulation software is used to evaluate the impacts of plenum volume and runner length on engine performance based on the afore-mentioned performance characteristics. Various intake manifold designs are iterated in accordance with the surface envelope rules imposed by FSAE and their characteristic curves are compared. Moreover, the proposed design is also compared with the stock intake manifold, which is usually provided by the manufacturer along with the engine to assess the results obtained. Hence an optimized intake system is designed. The use of rapid prototyping methods for the manufacturing of the intake system is also discussed in this study. The proposed new intake design is manufactured and tested on a dyno testing facility and the results are discussed.
Venugopal, Thangavel, Anubhav, Routray
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