Browse Topic: Racing engines

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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
McLaren: The Engine CompanyR-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
Developing High-Performance Motorcycle Oils2019-32-05051/24/2020
Published motorcycle lubricant research often focuses on developments to meet certain specifications, regulatory requirements, or a combination of the two. Seemingly missing from the literature is research where the primary goal is development of a lubricant that enables maximum torque, power and acceleration from a machine for the purpose of winning races. The present study combines the two areas of research, where a high-performance motorcycle engine oil platform is developed to be used in competition, while simultaneously meeting the necessary regulations and specifications to be useful for commuters and leisure riders alike. Well-known are the demands on a motorcycle oil, which must lubricate and protect the crankcase, clutch and gears, all of which have competing requirements such that a strategy to improve the performance in one area can cause a detriment in another. Formulating for racing engines that are typically much more powerful than production versions further exacerbates these dichotomies, where the traditional strategies for gaining power through the lubricant of reducing viscosity or adding friction-reducing chemistries can leave the clutch and gears open to severe damage. To meet these competing demands, a novel additive system with unique anti-wear and friction modifier chemistries was introduced to ensure clutch and gear protection while simultaneously improving power output and minimizing deleterious effects to aftertreatment devices. Further, the oils were designed to withstand the higher temperatures, speeds and power densities found in high performance machines through improved antioxidants, base stocks and shear-stable polymers, which also provide durability across the oil drain interval for leisure riders and commuters alike. Through a combination of performance bench testing, engine dynamometer testing and field testing on the track, it was demonstrated that substantial power gains can be achieved while still maintaining hardware protection, thus achieving the goal of a high-performance racing oil that is also suitable for everyday use.
Marcella, Mike, Johnson, Aaron
Using RON Synergistic Effects to Formulate Fuels for Better Fuel Economy and Lower CO2 Emissions2019-01-215512/19/2019
The knock resistance of gasoline is a key factor to decrease the specific fuel consumption and CO2 emissions of modern turbocharged spark ignition engines. For this purpose, high RON and octane sensitivity (S) are needed. This study shows a relevant synergistic effect on RON and S when formulating a fuel with isooctane, cyclopentane and aromatics, the mixtures reaching RON levels well beyond the ones of individual components. The same is observed when measuring their knock resistance on a boosted single cylinder engine. The mixtures were also characterized on a rapid compression machine at 700 K and 850 K, a shock tube at 1000 K, an instrumented and an adapted CFR engine. The components responsible for the synergistic effects are thus identified. Furthermore, the correlations plotted between these experiments results disclose our current understanding on the origin of these synergistic effects. This study concludes that this synergistic effect encourages formulating highly paraffinic fuels for lower specific fuel consumptions and CO2 emissions. Thus, paraffins are still relevant compounds to formulate highly efficient gasolines, despite their low octane sensitivity when individually considered. Furthermore, the CFR engine is still the best known device to anticipate synergistic effects in gasoline's knock resistance, through the Octane Index (OI = RON - K.S). A sensitivity study on the “K value” of the octane index shows that octane sensitivity mainly drives the gasoline performance for the low-sensitivity fuels while RON also drives it for the high-sensitivity ones.
Dauphin, Roland, Obiols, Jerome, Serrano, David, Fenard, Yann, Comandini, Andrea, Starck, Laurie, Vanhove, Guillaume, Chaumeix, Nabiha
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
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
A Review of Spark-Assisted Compression Ignition (SACI) Research in the Context of Realizing Production Control Strategies2019-24-00279/9/2019
This paper seeks to identify key input parameters needed to achieve a production-viable control strategy for spark-assisted compression ignition (SACI) engines. SACI is a combustion strategy that uses a spark plug to initiate a deflagration flame that generates sufficient ignition energy to trigger autoignition in the remaining charge. The flame propagation phase limits the rate of cylinder pressure rise, while autoignition rapidly completes combustion. High dilution within the autoignited charge is generally required to maintain reaction rates feasible for production. However, this high dilution may not be reliably ignited by the spark plug. These competing constraints demand novel mixture preparation strategies for SACI to be feasible in production. SACI with charge stratification has demonstrated sufficiently stable flame propagation to reliably trigger autoignition across much of the engine operating map. A key controls challenge of SACI is the two regimes of combustion are near several constraints that may be competing. This work summarizes key findings from decades of research that can help enable production control strategies for SACI engines. A summary and analysis of the broad research of SACI is included, along with an examination of the relevant factors that must be considered while developing a control strategy. Additionally, a discussion of how production-intent SACI designs extend or innovate upon previous decades of research is included. Key control actuators and design parameters are synthesized along with their sensitivity on several SACI combustion metrics.
Robertson, Dennis, Prucka, Robert
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
High Power-Density, High Efficiency, Mechanically Assisted, Turbocharged Direct-Injection Jet-Ignition Engines for Unmanned Aerial Vehicles01-12-01-00025/2/2019
More than a decade ago, we proposed combined use of direct injection (DI) and jet ignition (JI) to produce high efficiency, high power-density, positive-ignition (PI), lean burn stratified, internal combustion engines (ICEs). Adopting this concept, the latest FIA (Fédération Internationale de l’Automobile) F1 engines, which are electrically assisted, turbocharged, directly injected, jet ignited, gasoline engines and work lean stratified in a highly boosted environment, have delivered peak power fuel conversion efficiencies well above 46%, with specific power densities more than 340 kW/liter. The concept, further evolved, is here presented for unmanned aerial vehicle (UAV) applications. Results of simulations for a new DI JI ICE with rotary valve, being super-turbocharged and having gasoline or methanol as working fuel, show the opportunity to achieve even larger power densities, up to 430 kW/liter, while delivering a near-constant torque and, consequently, a nearly linear power curve over a wide range of speeds.
Boretti, Alberto
Investigation of an Innovative Combustion Process for High-Performance Engines and Its Impact on Emissions2019-01-00391/15/2019
Over the past years, the question as to what may be the powertrain of the future has become ever more apparent. Aiming to improve upon a given technology, the internal combustion engine still offers a number of development paths in order to maintain its position in public and private mobility. In this study, an innovative combustion process is investigated with the goal to further approximate the ideal Otto cycle. Thus far, similar approaches such as Homogeneous Charge Compression Ignition (HCCI) shared the same objective yet were unable to be operated under high load conditions. Highly increased control efforts and excessive mechanical stress on the components are but a few examples of the drawbacks associated with HCCI. The approach employed in this work is the so-called Spark Assisted Compression Ignition (SACI) in combination with a pre-chamber spark plug, enabling short combustion durations even at high dilution levels. This operation mode leads to substantial improvements in terms of fuel consumption up to highest load conditions. Developed in close collaboration with Volkswagen Motorsport and the FKFS, the experimental investigations are carried out on a single cylinder test bench at the Technical University of Munich (TUM). The test bench is directly derived from the Volkswagen WRC 1.6l DI-SI race engine. In a numerical approach, the 3D-CFD engine development tool QuickSim is used to gain a detailed understanding of charge motion, mixture formation, and combustion. As a first step, we want to assess the effects of engine operating parameters such as engine load and engine speed on both boosted conventional and SACI operation. Secondly, we want to give an overview on the magnitude of the formulation of NOx and particle emissions in the presence of different ignition modes. The latter is aimed at addressing one of the many remaining questions in order to apply SACI operation to series production engines.
Koch, Daniel, Berger, Vinicius, Bittel, Alexander, Gschwandtner, Maximilian, Wachtmeister, Georg, Chiodi, Marco, Kaechele, Andreas, Bargende, Michael, Wichelhaus, Donatus
Progress of Direct Injection and Jet Ignition in Throttle-Controlled Engines2019-26-00451/9/2019
Direct injection and jet ignition is becoming popular in electrically assisted, turbocharged, F1 engines because of the pressure to reduce fuel consumption. Operation from homogeneous stoichiometric up to lean of stoichiometry stratified about λ = 1.5, occurs with fast combustion of reduced cyclic variability thanks to the enhanced ignition by multiple jets of hot, partially reacting products travelling through the combustion chamber. The fuel consumption has thus been drastically reduced in an engine that is, however, still mostly throttle controlled. The aim of the present paper is to show the advantages of direct injection and jet ignition based on model simulations of the operation of a high-performance throttle-controlled engine featuring rotary valves.
Boretti, Alberto
Performance Improvements to a Production, Semi Direct Fuel Injected, 2-Stroke Engine for a Racing Application2018-32-004310/30/2018
The following material presents an overview of using a production 2-stroke engine and transforming it into one for the racing application of Snocross. This paper will explore the changing of engine hardware, engine related hardware and software while staying within the project scope for schedule, tooling capabilities and rules of the governing body for Snocross racing. This conversion process is discussed in detail through analytical calculations, to the experimental validation with dynamometer and airflow bench data.
Olson, Andy, Hayes, Ryan
Model-Based Approach for Engine Performance Optimization2018-32-008210/30/2018
State-of-the-art motorcycle engines consist of numerous variable components and require a powerful motor management to meet the growing customer expectations and the legislative requirements (e.g. exhaust and noise emissions, fuel consumption) at the same time. These demands are often competing and raise the level of complexity in calibration. In the racing domain, the optimization requirements are usually higher and test efficiency is crucial. Whilst the number of variables to control is growing, the time to perform an engine optimization remains the same or is even shortened. Therefore, simulation is becoming an essential part of the engine calibration optimization. Considering the special circumstances in racing, involving valuable hardware, as well as extremely short development and calibration iteration loops, only transient testing is possible. By utilizing model-based testing and optimization, Ducati Corse, the racing team division of the well-known motorcycle manufacturer Ducati, improved the ability to optimize their race engines efficiently. By using an engine model it is possible to make extremely quick calibration adaptations. All parameters can easily be optimized with respect to potential constraints without running the engine on a testbed. Moreover, the re-use of the engine model for co-simulations is applicable and sharing it with other departments in the company is possible to increase efficiency even more. AVL CAMEO™ - the intelligent automated calibration environment - supports all engine optimization requirements with a consistent workflow from the task definition to the verification. For this specific racing use case, the software solution was implemented for the test planning using DoE (Design of Experiment), the data plausibility check and the empirical engine modeling. In addition, AVL CAMEO™ was the tool for realizing the model-based optimization and map creation. With the implementation of the model-based approach, the motorcycle manufacturer has successfully improved the engine performance optimization. An exact model of the engine is now available which supports a deep understanding of the engine behavior. Through realizing this calibration approach, quick office and race track adaptations are possible and alternative optimizations for different tracks or conditions are easy to execute.
Bartoccini, Davide, Niedermaier, Peter, Grassberger, Helmut Peter
Methodical Selection of Sustainable Fuels for High Performance Racing Engines2018-01-17499/10/2018
As the importance of sustainability increases and dominates the powertrain development within the automotive sector, this issue has to be addressed in motorsports as well. The development of sustainable high-performance fuels defined for the use in motorsports offers technical and environmental potential with the possibility to increase the sustainability of motorsports at the same or even a better performance level. At the moment race cars are predominantly powered by fossil fuels. However due to the emerging shift regarding the focus of the regulations towards high efficient powertrains during the last years the further development of the used fuels gained in importance. Moreover during the last decades a huge variety of sustainable fuels emerged that offer a range of different characteristics and that are produced based on waste materials or carbon dioxide. This study investigates the question of which sustainable fuels offer the characteristics suitable for high-performance race engines. Equivalents to gasoline, diesel and natural gas are examined separately in order to present the options with various engine concepts. The requirements for a high-performance fuel are defined based on experimental investigations emphasizing among other characteristics the importance of the knock resistance for gasoline-like fuels and the ignitability for diesel-like fuels. Furthermore the characteristics of the sustainable alternatives are analyzed. On the basis of the experimental results a comparison is carried out to match the fuel requirements with the characteristics and to select the optimal equivalent for fossil gasoline, diesel and natural gas. Moreover the sustainable fuels are evaluated with an environmental analysis including the fuel life cycle. The results show a potential to reduce the greenhouse gas emissions per mega joule energy content by up to 88%. This research assesses the broad variety of sustainable biologic and synthetic fuels concerning the potential use in motorsports and the resulting environmental benefits.
Schwarz, Lea, Bargende, Michael, Dreyer, Stefan, Baretzky, Ulrich, Kotauschek, Wolfgang, Wohlgemuth, Sebastian, Bach, Florian
Improvement of Formula Student Racecar Performance with Rotary Variable Runner Length for the Intake System2018-01-09774/3/2018
The purpose of this research is to implement the variable intake manifold on a Formula Student racecar to achieve a lower overall Autocross lap time. A previous version of the linearly adjustable variable intake manifold prototype was able to deliver an improved engine performance in the form of wider range of engine RPM with high torque, but its dimension did not conform to the FSAE regulation. This research focuses on developing a physically compact rotary variable intake system to achieve a favorable characteristic while conforming to the FSAE rules. The engine is expected to perform better than the previous one by comparing the range of engine RPM which produces torque greater than 48.47 N-m, representing 90% of maximum torque or our 2015 car with a conventional intake system. The optimum runner length is determined using the pressure wave tuning method. CFD analysis is performed to determine the inlet-plenum diameter ratio to ensure uniform mass flow distributions among four runners. The plenum housing is constructed using carbon fiber composites with an allowable maximum displacement of 1 mm during operation. Finally, a rotary variable intake system is built and installed in the 2016 racecar. Test results from a chassis dynamometer between 4,000-11,500 engine RPM at all possible runner lengths show that the rotary variable intake system is able to deliver torque above 48.47 N-m over the range of 7,035-9,307 RPM (range of 2,272 RPM), which is 69.17% wider than the previous car’s power band between 5,784-7,127 RPM (range of 1,343 RPM). The maximum power achieved by the rotary variable intake system is 50.175 kW, which sees an increase of 7.66 kW. The results have successfully shown that the rotary variable intake system can enhance the car performance and ultimately help reduce the lap time at the Autocross event by 1.07 second or 1.53%.
Chantharasenawong, Chawin, Chanta, Alongkorn, Siripongarpone, Pongsiri, Kaoudom, Supawit
Model-Based Control of Test Bench Conditioning Systems2018-01-01294/3/2018
Engine test benches are crucial instruments to perform tests on internal combustion engines. Since many factors affect tests results, an engine test bench is usually equipped with several conditioning systems (oil, water and air temperature, air humidity, etc.), in order to maintain the controlled variables to the target values, throughout the test duration. The conditioning systems are often independently controlled by means of dedicated programmable logic controllers (PLC), but a centralized model-based management approach could offer several advantages in terms of promptness and accuracy. This work presents the application of such control methodology to oil, water, and HVAC (heating, ventilating, and air conditioning) conditioning systems, where each actuator is managed coupling model-based open loop controls to closed loop actions. The main advantage of integrating the management of several actuators is that the control actions can be coordinated, similarly to what has been achieved in engine management systems with torque-based control: the risk of conflicts in the control actions on different actuators can be reduced, while the introduction in the control loops of other actuators is easier. The control methodology has been validated on an engine test bench where the automation system has been developed on an open software real-time compatible platform, allowing the integration of the conditioning system control with all other functionalities concerning the test management. This article shows the plant layout, details the control strategy, and finally analyzes experimental results obtained on the test bench, highlighting the benefits of the proposed management approach.
Corti, Enrico, Taccioli, Michele, Ponti, Fabrizio
Virtual Optimization of Race Engines Through an Extended Quasi Steady State Lap Time Simulation Approach2018-01-05874/3/2018
Minimizing the lap time for a given race track is the main target in racecar development. In order to achieve the highest possible performance of the vehicle configuration the mutual interaction at the level of assemblies and components requires a balance between the advantages and disadvantages for each design decision. Especially the major shift in the focus of racecar powerunit development to high efficiency powertrains is driving a development of lean boosted and rightsized engines. In terms of dynamic engine behavior the time delay from requested to provided torque could influence the lap time performance. Therefore, solely maximizing the full load behavior objective is insufficient to achieve minimal lap time. By means of continuous predictive virtual methods throughout the whole development process, the influence on lap time by dynamic power lags, e.g. caused by the boost system, can be recognized efficiently even in the early concept phase. As a first step, this paper presents a novel method that combines detailed 1D (one dimensional) gas dynamic engine models with the quasi steady state (QSS) lap time method. This allows for a predictive comprehension of lap time influence for different engine design parameters with the possibility to operate in an environment of detailed description of vehicle dynamics. Moreover, the direct application of 1D-CFD (computational fluid dynamics) engine models also increases the efficiency of the used virtual engineering tools. In a second step, this paper gives an insight into a model supported development process of a lean boosted 4-cylinder race engine. An evaluation of the model’s predictive capabilities and a sensitivity study of basic boost system parameters are also part of this publication.
Malcher, Simon, Bargende, Michael, Grill, Michael, Baretzky, Ulrich, Diel, Hartmut, Wohlgemuth, Sebastian
A Study Isolating the Effect of Bore-to-Stroke Ratio on Gasoline Engine Combustion Chamber Development2016-01-217710/17/2016
A unique single cylinder engine was used to assess engine performance and combustion characteristics at three different strokes, with all other variables held constant. The engine utilized a production four-valve, pentroof cylinder head with an 86mm bore. The stock piston was used, and a variable deck height design allowed three crankshafts with strokes of 86, 98, and 115mm to be tested. The compression ratio was also held constant. The engine was run with a controlled boost-to-backpressure ratio to simulate turbocharged operation, and the valve events were optimized for each operating condition using intake and exhaust cam phasers. EGR rates were swept from zero to twenty percent under low and high speed conditions, at MBT and maximum retard ignition timings. The increased stroke engines demonstrated efficiency gains under all operating conditions, as well as measurably reduced 10-to-90 percent burn durations. The results were quite non-linear, with the majority of the gains achieved in going from the 1:1 to 0.87:1 bore-to-stroke ratio cases. The further change to 0.75:1 showed significantly diminished returns. Flame speed and chamber geometry estimates were used to project further advantages at reduced bore and constant displacement.
Hoag, Kevin L., Mangold, Barrett, Alger, Terrence, Abidin, Zainal, Wray, Christopher, Walls, Mark, Chadwell, Christopher
Technology Choices for Optimizing the Performance of Racing Vehicles2016-01-11734/5/2016
In the continuous search for technology to improve the fuel economy and reduce greenhouse gas emission levels from the automotive vehicle, the automotive industry has been evaluating various technological options. Since the introduction of stringent legislative targets in Europe as well as in the United States of America in late 20th Century, one of the viable options identified by the industry was the application of alternative powertrain. On the motorsport arena, changes introduced by the Formula 1 governing body (FIA) for the high-performance racing engines also focuses on fuel economy. FIA regulation for 2014 restricts the fuel-flow rate to a maximum of 100kg/hr beyond 10,500 rev/min and prescribe fuel flow rate below 10,500 rev/min operating conditions for the F1 Engines. In addition, Formula1 and Le Mans racing regulations actively promote the integration of the hybrid powertrain in order to achieve optimum fuel economy. Therefore, the aim of the present work is to evaluate available technology choices and measure efficiency in terms of fuel consumption and CO2 emission level. This technology mining exercise has been carried out using a powertrain simulation tool based on a mid-size light duty vehicle. The benchmark powertrain architecture for a light-duty vehicle is based on legislative drive cycle. The technologies tested on the drive cycles are also to be tested in a racing prototype car (LMP1), around a lap at Le Mans Circuit. This report presents a systematic methodology for assessing technology choices for racing vehicle using powertrain simulation tool. It presents a merit matrix based on fuel economy, drive cycle energy analysis, to evaluate the powertrain ability to harvest the available energy on a given drive cycle.
Bengolea, Federico, Samuel, Stephen
Transient Gas Exchange Simulation and Uniflow Scavenging Analysis for a Unique Opposed Piston Diesel Engine2016-01-10874/5/2016
To achieve more stringent exhaust emission regulations will face more and more daunting challenges nowadays. It needs more new technologies to improve the IC engine performance but needing higher costs in order to meet Euro 6 and EPA standards in USA. Recently the opposed-piston engine (OPE) has been treated as the promising product to meet these new regulations but relatively lower costing. Although two-stroke OPE owning inherent thermal efficiency and power density advantages, the inefficient scavenge efficiency appears to become the main obstacle to enhance combustion efficiency whilst reducing exhaust gas emission. For the improvement of scavenge efficiency the transient gas exchange simulation was carried out for multiple Cases here, including two intake port configurations at various back pressures in exhaust system and two port timings. The effects of exhausting back pressure, porting timing and intake port layout on scavenging and trapped air mass in cylinder all were investigated by transient CFD simulation including blow-down and scavenging. The calculated results showed that for Case02 that intake port entrance orientation with a right tilt angle referred to baseline, the scavenge efficiency is relatively higher than one with left tilt angle in Case01 for different exhausting back pressures, also for trapped fresh air mass. The turbulence kinetic energy is extremely sensitive to back pressure in exhaust chamber. The investigation was also found that the port timing is also quite important for scavenging process and pump losses, and there will be a little increase of scavenge efficiency by about 2-3% via adjusting port timing for both Cases, and the net trapped masses are approximate to each other but with less fresh air leakage for new port timing. Apparently, the exhaust back pressure will impose much more considerable influence on the entire scavenging performance than the port timing, as using uniflow scavenge mode in a two-stroke opposed piston diesel engine.
Changming, He, Sichuan, Xu
Port Design Criteria for 2-Stroke Loop Scavenged Engines2016-01-06104/5/2016
Interest in 2-stroke engines has been recently renewed by several prototypes, developed for the automotive and/or the aircraft field. Loop scavenging, with piston controlled ports is particularly attractive, but the configurations successfully developed in the past for motorbike racing (in particular, the 125cc unit displacement, crankcase pump engines), are not suitable for automotive applications. Therefore, new criteria are necessary to address the scavenging system design of the new generation of 2-stroke automobile/aircraft engines. The paper reviews the transfer ports optimization of a loop scavenged 2-stroke cylinder, whose main parameters were defined in a previous study. The optimization has been carried by means of a parametric grid, considering 3 parameters (2 tilt angles, and the focus distance), and 3 different engine speeds (2000-3000-4000 rpm, assuming a Diesel engine). A set of scavenging CFD-3d simulations have been performed by using a customized version of KIVA-3V. The numerical approach was experimentally calibrated in a previous project (see appendix 1) The simulations results are presented by means of maps showing the influence of the geometrical parameters on the main scavenging coefficients. Finally, a refined mesh has been constructed for the optimum configuration found in the previous parametric analysis, and a set of multi-cycle simulations have been performed. The results demonstrated the very good efficiency of the scavenging process, close to a perfect displacement for delivery ratio up to 1.5, or for residuals fraction higher than 50%
Mattarelli, Enrico, Rinaldini, Carlo Alberto, Savioli, Tommaso
Development of a Third Generation Dynamic Intake Air Simulator for Single-Cylinder Test Engines2015-01-08854/14/2015
This paper details the development of a new dynamic Intake Air Simulator (IAS) for use on single-cylinder test engines, where the gas dynamics are controlled to accurately simulate those on a multi-cylinder engine during transient or steady-state operation. The third generation of Intake Air Simulators (IAS3) continues a development of new technology in the Powertrain Control Research Laboratory (PCRL) that replicates the multi-cylinder engine instantaneous intake gas dynamics on the single-cylinder engine, as well as the control of other boundary conditions. This is accomplished by exactly replicating the intake runner geometry between the plenum and the engine intake valve, and dynamically controlling the instantaneous plenum pressure feeding that runner, to replicate the instantaneous multi-cylinder engine intake flow. The plenum pressure is controlled in this technology by means of six rotary valves, seven proportional valves, and the throttle valve system from the representative multi-cylinder engine. The proportional valves control the magnitude of flow through the rotary valves, and the rotary valves control the instantaneous wave form of the flow out of the plenum by means of their rotational speed. This flow out represents the net instantaneous flow out of the plenum that would otherwise go to the other cylinders in the multi-cylinder engine. The single-cylinder engine using this technology will have the same gas dynamics as if it were in a multi-cylinder engine, and the results of studies in charge motion, mixing, combustion, and even engine performance will be much more representative of what would be expected on the multi-cylinder engine.
Murphy, Mark B., Moskwa, John J.
Performance of Ancillary Systems of 2014+ Le Mans LMP1-H Vehicles and Optimization2015-01-11634/14/2015
This study details the investigation into the hybridization of engine ancillary systems for 2014+ Le Mans LMP1-H vehicles. This was conducted in order to counteract the new strict fuel-limiting requirements governing the powertrain system employed in this type of vehicle. Dymola 1D vehicle simulation software was used to construct a rectilinear vehicle model with a map based 3.8L V8 engine and its associated ancillary systems, including oil pumps, water pump and fuel pump as well as a full kinetic energy recovery system (ERS). Appropriate validation strategy was implemented to validate the model. A validated model was used to study the difference in fuel consumption for the conventional ancillary drive off of the internal combustion engine in various situational tests and a hybrid-electric drive for driving engine ancillaries. Investigation showed that the implementation of hybrid ancillaries in the Le Mans circuit would achieve a 40cc fuel savings per lap over the conventional ancillary system. As well as this, in a straight-line acceleration test, the hybrid ancillary-equipped vehicle model reached its maximum speed 1.1 seconds quicker than the conventional ancillary-equipped vehicle. This paper presents the methodology followed for modelling a rectilinear vehicle system and the engine with complete ancillaries that can draw power directly from the engine or from the electric drive, the strategy implemented in the vehicle system for achieving optimum fuel economy benefit and the systematic approach followed in this work for validating the results.
Elias, Gabriel, Samuel, Stephen, Picarelli, Alessandro
A Study into Compression Ring Dynamics using Response Surface Methodology2015-01-13354/14/2015
For decades the operational dynamics of the compression ring during operation, have been subject to debate [1, 2, 3, 4, 5, 6, 7]. A complex computer simulation, using Design Of Experiments (DOE) methodology, was developed to study the effect of the compression ring rotation during running-in stages. Response Surface (RS) has been used to optimize ring displacement, as function of ring mass, width and radius. The optimised surface response has been compared to used compression rings and has shown a 2% variation between calculated and measured values.
Dickinson, Matthew W., Renevier, Nathalie, Calderbank, John
Demands on Future Timing drives - Chain and Belt in Competition2015-01-12754/14/2015
When designing a new internal combustion engine, the choice of technology for the timing drive system is one of the key decisions that determines the overall characteristics of the engine with far reaching implications on the remaining architecture and overall packaging of the engine. For Passenger car engines there are two mainstream technologies: toothed belts and chains. Each of these offers several sub-variants, such as dry vs. wet belt, or toothed vs. roller chain. This paper examines the differences between these technologies in relation to the key engine attributes including package, cost, weight, durability, NVH and frictional losses. A quantitative evaluation is made where possible, based on data collected from recent engine development programs, backed up by literature study and data from the component supply industry. These differences are reviewed in the light of current and expected future engine development trends in order to give a basis for the engine designer to choose the appropriate technology for coming years.
Schoeffmann, Wolfgang Johann, Truffinet, Caroline, Howlett, Michael, Ausserhofer, Norbert, Zurk, Andreas
Turbo/Supercharged Two/Four Stroke Engines with One Intake and One Exhaust Horizontal Rotary Valve per Cylinder and Central Direct Injection and Ignition2015-26-00311/14/2015
The present paper is an introduction to a novel rotary valve engine design addressing the major downfalls of past rotary valves applications while permitting the typical advantages of the rotary valves. Advantages of the solution are the nearly optimal gas exchange, mixture formation, ignition and combustion evolution thanks to the large gas exchange areas from the two horizontal valves per engine cylinder, the good shape of the combustion chamber, the opportunity to place a direct fuel injector and a spark or jet ignition device at the centre of the chamber. The novel engine design also permits higher speed of rotation not having reciprocating poppet valves and the reduced friction losses of the rotating only distribution. This translates in better volumetric efficiencies, combustion rates and brake mean effective pressures for improved power density and fuel efficiency. Additional advantages are the reduced weight and the better packaging. The paper proposes some CAD/CAE results but does not give details of a specific development being the further CAD/CAE study and the following prototyping and experiments just started with the acquisition of a single cylinder motorcycle engine to modify and test.
Boretti, Alberto, Scalzo, Joseph
Piston Temperature Measurement in Internal Combustion with Telemetric Method2014-32-005111/11/2014
Currently, the improvement of fuel economy is the most important issue in automobile engine development. To improve fuel economy via greater thermal efficiency, the enhancement of the compression ratio and the reduction of thermal losses because of cooling have been widely investigated. These efforts to improve thermal efficiency increase the thermal load on pistons. Ensuring the reliability of the pistons and the antiknocking capacity of engines require a better understanding of piston temperature distributions through accurate measurements under various engine operating conditions. Thus, direct and indirect measurement methods have been developed to estimate the actual piston temperature. Direct methods, such as linkage-type measurements, are not typically applicable under higher engine speeds because of the poor durability of linkages. Indirect methods, such as material hardness-type measurements, can measure neither real-time piston temperature nor the temperature of piston skirts, which are thin-walled. Therefore, the conventional measurement systems no longer satisfy the measurement requirements under various engine operating conditions. In this work, we have developed a telemetry-type method in which thin diametric thermocouples are installed at six points in each piston. This method enables the measurement information to be transferred wirelessly at the bottom dead center using electromagnetic induction. This approach has enabled real-time and transitional measurements at engine speeds up to 6500 rpm in a four-cylinder gasoline engine. In addition, the experimental and calculated results are compared via 1-dimensional analysis to validate the accuracy of our method.
Ishibashi, Akira, Nakamura, Muneaki, Muramatsu, Hitoshi
Cylinder Pressure Based Engine Calibration of a Formula SAE Racing Engine2014-36-03509/30/2014
Formula SAE racing engines must provide high output with maximum fuel efficiency despite the air restriction imposed by the rules. Throttle response and engine load control are very important due to the track characteristics with a few straights zones and many curves. In-cylinder pressure cyclic variations harm vehicle control and increase fuel consumption, due to the torque fluctuations. In order to reduce fuel consumption and improve vehicle drivability, engine calibration having the in-cylinder as a feedback parameter is an essential procedure and will be the focus of this paper. Test bench data with combustion analysis will be performed, using the COVIMEP as a combustion stability index. Tests were carried out on a motorcycle engine modified to run under the Formula SAE competition rules. A piezoelectric sensor was installed inside the combustion chamber to provide instantaneous pressure readings, which were used to on-line calculate the IMEP and perform a 200 cycle COVIMEP evaluation. The objective was to reduce the combustion variability at speeds and loads conditions which were defined as critical when analyzing track logged data from previous competitions. Air-fuel ratio and spark timing were varied and combined to reach a good compromise among COVIMEP, torque and fuel consumption. Values in the range of 2-5% on COVIMEP were achieved at part load operation conditions with an increase on torque and an expressive reduction on fuel consumption.
Tatsch, Gabriel Azevedo, Martins, Mario Eduardo Santos, Lanzanova, Thompson, Sari, Rafael Lago, Taglieber, Victor Hugo, Görck, Cassio Lino
Sports cars embrace array of green technology14AUTP07_027/1/2014
IMSA Tudor United SportsCar Championship promotes a variety of green technologies to link racing to the road. The International Motor Sports Association's Tudor United SportsCar Championship is the newly merged racing series for sports car racing in North America, ending the split between the American Le Mans Series and the Grand-Am racing series. One way the new series aims to boost interest in its racing and its cars is by strengthening the link between the cars on the track and those on the street. This gives manufacturers and fans alike more reason to be interested in the racing series.
Carney, Dan
A New Technique to Determine the Burning Velocity in a Gasoline Direct Injection Engine2014-01-11764/1/2014
Many approaches have been taken to determine the burning velocity in internal combustion engines. Experimentally, the burning velocity has been determined in optically accessible gasoline engines by tracking the propagation of the flame front from the spark plug to the end of the combustion chamber. These experiments are costly as they require special imaging techniques and major modifications in the engine structure. Another approach to determine the burning velocity is from 3D CFD simulation models. These models require basic information about the mechanisms of combustion which are not available for distillate fuels in addition to many assumptions that have to be made to determine the burning velocity. Such models take long periods of computational time for execution and have to be calibrated and validated through experimentation. This paper presents a new technique to determine the burning velocity in a production engine without making any modification in its structure, or use of high speed imaging equipment. This technique is based on the combustion produced ionization measured at two defined locations in the combustion chamber. In the engine used in this investigation, the spark plug is used as an ion current sensor which indicates the time the flame kernel is formed around the spark plug gap. In addition, the fuel injector is used as an ion current sensor, after it is electrically insulated from the cylinder head. The time between the start of ionization at the two locations is used to calculate the burning velocity. The use of this technique to determine the cycle to cycle variation in the burning velocity and other combustion parameters is demonstrated with engine operation at a steady speed and load.
Mekhael, Shenouda, Estefanous, Fadi, Henein, Naeim, Zahdeh, Akram
A Novel Valve-Less Supercharged Small Two Stroke Engine of Top Brake Efficiency Above 36% and Power Density above 100 KW/Liter2013-01-277211/27/2013
The paper presents a novel design for a two stroke thermal engine that delivers excellent fuel economy and low emissions within the constraints of today's cost, weight and size. The engine features asymmetrical port timing through a novel translating and rotating piston mechanism. The engine is externally scavenged and supercharged, has wet sump and oil pressure lubrication, direct injection, it is lightweight, easy to build, with minimal number of parts, low production cost, ability to be balanced and compact design. The two stroke mechanism produces a linear motion of the pistons as well as an elliptical path on the surface of the cylinder. This allows the piston to sweep as well as travel past the ports. Suitable slots around the raised lip of the piston generate the asymmetry that makes the exhaust port to open first and to close first. The inlet port remains open to complete the cylinder charging and allow supercharging. Direct fuel injection is adopted for best results. The paper includes design features as well as result of engine performance simulations.
Boretti, Alberto, scalzo, joseph
Improving the Fuel Economy of Supercharged Engine2013-32-911810/15/2013
The paper reviews the experimental development of fuel economy of engine powering the 2012 Formula SAE single seat race car of the University of Sophia. The balance of high power and low fuel consumption is biggest challenge of racing engine. It was found that improving the efficiency of engine by supercharging as a way to achieve that. In order to adapt the supercharger for the engine, the important design points are below: It was found that intake air blow-by gas at combustion chamber is increased in low engine speed. To improve that, the valve overlap angle was changed to adopt supercharged engine and improve effective compression ratio. Typically the racing engine demands maximum torque for performance but that does not imply that the air fuel ratio should be rich than theoretical. The point is the maximum torque of the engine is proportional to the amount of air intake. Therefore, supercharged engine is possible to increase the supercharging pressure for bigger torque. But the base engine is not prepared for bigger torque, the damage of the engine was considered. In order to avoid engine breakage, the lean air-fuel ratio was used and maximum torque was controlled not to exceed an engine limit. The aim air fuel ratio was change by engine speed to get more flat torque performance, and improved the fuel consumption.
Fukuhara, Yoshiki, Kimata, Naoya, Suzuki, Takashi
Optimising Piston Ring Contact Face Chamfer for High Performance Engines2013-01-09654/8/2013
Internal combustion engine components have been a main research interest over many decades [1]. While bulk material and surface engineering developments have improved the resistance to fatigue, reduced the amount of wear and friction during operation, small improvements in race applications designs can increase the engine performance and give a competitive edge to racing engines. Piston rings are designed to create a seal which means that they will suffer large levels of material loss due to wear during operation. The compression ring is the top or closest ring to combustion gases and is exposed to the highest operating temperature. In this paper, the authors propose a design modification to the compression ring coated chamfer which can reduce stress concentration and material loss during operation.
Dickinson, Matthew W.
Valve Lift Profile Development and Optimization Using Matlab2013-01-17224/8/2013
The focus of this paper is the development and modelling of a reverse-poppet valve train assembly, placing a major emphasis on the optimization routine used to develop a short-duration camshaft profile. A user-programmable script, known as the penalty function, was written to assign weighted numeric values to certain parameters associated with the valve lift profile and its derivatives. These design parameters include maximum acceleration, peak lift, area under the lift curve and minimization of jerk. Optimization tools built into Matlab were then used to generate a profile which minimizes the overall ‘penalty’ associated with each parameter as it deviates from a user-defined ideal. A commercially available multi-body dynamics software package was used to evaluate the dynamic performance of the valve train incorporating the generated cam profile. A flexible-body spring element provided insight into spring surge and coil contact. Comparisons of the designed and simulated lift, velocity and acceleration profiles are given.
Cameron, Iain, Minaker, Bruce
The Impact of Cellulosic Ethanol on the Performance and Emissions of a Circle Track Race Car2013-01-11494/8/2013
Ethanol has received both positive and negative attention as a renewable fuel for spark ignition engines. Studies of ethanol have shown improved volumetric efficiency, knock tolerance, and favorable burn curves[1]. Nevertheless, little research has been published exploring the impact of ethanol blends on race engine performance coupled with the impact on well-to-wheels (WTW) greenhouse gases, emissions, and petroleum reduction. In this work, a circle track race vehicle powered by a GM Performance Parts 6.2L OHV CT-525 engine was tested using 100 octane race fuel and E85 over a matrix of configurations. Carburetion vs. fuel injection configurations were benchmarked with both fuels, with the addition of 100- and 300-cells-per-inch catalytic convertors. Testing involved both dynamometer testing and on-track testing utilizing a portable emissions measurement system. These data were used to determine the WTW greenhouse gas reduction, petroleum displacement, and criteria emission reduction, as well as the performance benefit, of E85 vs. race fuel over a matrix of technologies. Results show an increase in power for 87% of the drive cycle using E85 as compared to 100 octane race fuel. Using 85% cellulosic ethanol, WTW greenhouse gas reductions are on the order of 63%, and petroleum reductions are on the order of 81%. Additionally, performance increases are maintained using catalytic convertors and E85 relative to 100 octane race fuel and carburetion. For comparison, it is shown that utilizing an 85% blend of cellulosic ethanol, petroleum consumption and greenhouse gas impacts are similar in magnitude to those of a mid-sized, four-door sedan using standard fuel driving over mixed city/highway cycles.
Jehlik, Forrest, Bocci, Daniel
Optimized Air Intake for a Turbocharged Engine Taking into Account Water-Cooled Charge Air Cooler Reflective Properties for Acoustic Tuning2013-01-05754/8/2013
Unsteady intake wave dynamics have a first order influence on an engine's performance and fuel economy. There is an abundant literature particularly for naturally aspirated SI engines on the subject of intake manifolds and primary runner lengths aimed to achieve a tuned intake air line. A more demanding design for today's engines is to increase efficiency to meet the requirements of lower fuel consumption and CO2 emissions. Today's tendencies are downsizing the engine to meet these demands. And for drivability purposes, the engine is combined with a turbocharger coupled with a charge air cooler. However, when the engine's displacement is reduced, it will be very dependent on its boosting system. A particularly interesting point to address corresponds to the engine's operation in the low speed range and during transients where the engine has large pumping losses and poor boost pressure. This operation point can be optimized using acoustic supercharging techniques. The proposed solution for a turbocharged engine is through an optimized air intake system from the compressor outlet to the intake valves. In this paper such a dedicated line is experimentally proposed on a four cylinder Diesel engine. First the reflective properties of a water-cooled charge air cooler are highlighted and compared to a traditional air charge cooler. This was done experimentally on an engine test bench using wave decomposition techniques through forward and backward components. Secondly this reflection is put to use by employing an adequate pipe length between the intake manifold and the charge air cooler aimed to improve low end torque and transient response. A series of pipe lengths were investigated and a final one is shown to give the greatest pressure wave amplitudes upstream of the intake valves for a low rpm range where the compressor provides little work. As a result it is shown that acoustic tuning is still possible on a turbocharged engine with a reduced plenum volume thus keeping costs low. Finally a GT-Power model of the engine is built where the exhaust and intake lines were correctly modeled. Then, the dynamics of intake system were replaced by an artificial excitation boundary which can be controlled independently and would correctly interact with the intake valves. Thus the optimized pressure waves obtained from the experimental measurements are fed directly into the intake of the model. The latter calculates the mean value of pressure only. Therefore rendering possible the prediction of the CO2 gain obtained from such an optimized line.
Mezher, Haitham, Migaud, Jerome, Raimbault, Vincent, Lelong, Jean-Gabriel, Chalet, David, Perrot, Nicolas, Hunault, Alexandre, Chesse, Pascal, Huurdeman, Bernhard
Assessment of the Influence of Intake Duct Geometrical Parameters on the Tumble Motion Generation in a Small Gasoline Engine2012-32-009510/23/2012
During the last years the deep re-examination of the engine design for lowering engine emissions involved two-wheel vehicles too. The IC engine overall efficiency plays a fundamental role in determining final raw emissions. From this point of view, the optimization of the in-cylinder flow organization is mandatory. In detail, in SI engines the generation of a coherent tumble vortex having dimensions comparable to the engine stroke could be of primary importance to extend the engines' ignition limits toward the field of the dilute/lean mixtures. For motorbike and motor scooter applications, the optimization of the tumble generation is considered an effective way to improve the combustion system efficiency and to lower emissions, considering also that the two-wheels layout represents an obstacle in adopting the advanced post-treatment concepts designed for automotive applications. The aim of the paper is to use the 3D-CFD simulation tool to assess the intake duct geometry influence on the tumble motion generation during both the intake and the compression strokes. All the CFD simulations presented in the paper were performed on a SI 4-valve engine characterized by a unit displacement of 250 cm₃. The tumble structure was changed during the analysis by changing the angle set defining the intake port shape. The stroke-to-bore engine ratio was kept constant to 0.7. The effects of the tumble variations were evaluated on the in-cylinder vortex characteristic length and vorticity, and on the cylinder mean flow structure at IVC. 3D-CFD simulations were performed by AVL-FIRE v.2010 CFD code.
Falfari, Stefania, Brusiani, Federico, Bianchi, Gian Marco
An Empirically Integrated CFD Method for Racing Engine Layout and Its Practical Demonstration2012-32-006810/23/2012
Racing engines are required to be developed quickly in order to adapt to ever-changing regulations. A CFD-based optimization would be a useful tool to discover the best solution given the restrictions of the regulations. However, a CFD approach requires repeated trials and errors until the best solution is found because the numerical goal is unknown and the specifications required for the goal are never calculated back when using CFD. Therefore, this paper proposes an Empirically Integrated CFD Method. It is a combination of a one-dimensional CFD and several empirical equations that are derived from the racing engine database with physical meanings. These empirical equations give the CFD-based optimization a proper goal and primary specifications so as to make the optimization loop converge rapidly. This method is experimentally verified for its practical application with a prototype engine. Moreover, this prototype engine reveals the impact of the combustion chamber design on the thermal efficiency, which has not been reflected in conventional CFD. As a result of this study, the Empirically Integrated CFD Method for Racing Engine Layout is established.
Yasui, Shinsuke, Nakamura, Daisuke
KERS Braking for 2014 F1 Cars2012-01-18029/17/2012
Small, high power density turbocharged engines coupled to kinetic energy recovery systems are one of the key areas of development for both passenger and racing cars. In passenger cars, the KERS may reduce the amount of thermal energy needed to reaccelerate the car following a deceleration recovering part of the braking energy. This translates in a first, significant fuel energy saving. Also considering the KERS torque boost increasing the total torque available to accelerate the car, large engines working at very low brake mean effective pressures and efficiencies over driving cycles may also be replaced by small higher power density engines working at much higher brake mean effective pressures and therefore much higher part load efficiencies. In racing cars, the coupling of small engines to KERS may improve the perception of racing being more environmentally friendly. The KERS is more a performance boost than a fuel saving device, permitting about same lap times with smaller engines. The actual fuel saving is therefore only the one of the smaller thermal engine having less thermal power. New F1 2014 power train rules may pave the way for a fuel economy KERS development for racing that may also be beneficial to road applications. The paper presents 2014 F1 engine and KERS hypotheses and simulation of lap times.
Boretti, Alberto
The Use of Computer Simulation for Development of a Four-Cylinder Race Engine2011-36-009510/4/2011
This paper presents the development of an ethanol fueled high performance engine for drag racing. Through the use of a specific software (AVL Boost) it was possible to model and simulate the performance of the engine being developed. The initial parameters required for modeling and the geometry of the various engine components were obtained by direct measurements and data from the literature. Model validation was achieved by comparing simulation results with data found in literature. After that, various engine configurations had been simulated, changing design parameters in order to optimize engine performance. The analysis of simulation results enabled the selection of different components to be manufactured or purchased in order to achieve a high-performance engine for use in drag race competition, with improved torque and power.
de Souza, Diogo J., Martins, Mario E.S.
Overview of Diesel Engine Applications for Engine System Design - Part 2: General Performance Characteristics2011-01-21799/13/2011
Diesel engine performance and design characteristics are affected by applications. Understanding general performance characteristics and the relationship between engine system design and applications is important for diesel engine system design engineers. This paper is the Part 2 of a series of three companion papers (parts) addressing diesel engine applications (i.e., Part 1 - organization design and systems engineering; Part 2 - general performance characteristics; and Part 3 - operating and design characteristics of different applications). It illustrates important general characteristics with selected examples, and highlights key issues and commonalities of different applications that engine system design engineers need to know. Series design and multi-purpose design are summarized. Four core equations in an engine air system theory are proposed in order to reveal the parametric dependency of pumping-loss-related parameters. An interactive and coupled design methodology of engine-drivetrain system is developed. A formula of calculating the isentropic engine retarding power of compression-release brakes is proposed. Valvetrain dynamics and valvetrain system design are summarized. The interactions between valvetrain and turbocharger in engine air system design are revealed. A low-pumping-loss WE- VVA (wastegating elimination intake variable valve actuation) system is discovered by using simulation analysis with air system capability charts. A fundamental engine trade-off between peak cylinder pressure and exhaust manifold gas temperature is discovered. Selected references are provided in the review portion.
Xin, Qianfan (Harry)
Improvement of a High-Performance CNG-Engine Based on an innovative Virtual Development Process2011-24-01409/11/2011
Methane as an alternative fuel in motorsports? Actually this solution is well known for the reduction of CO₂ emissions but apparently it does not really awake race feelings. At the 2009 edition of the 24-hour endurance race on the Nürburgring the Volkswagen Motorsport GmbH, in addition to vehicles powered by gasoline engines, introduced two vehicles powered by innovative turbo-charged CNG engines for the first time. The aim was to prove, that also an "environment-friendly" concept is able to provide the required efficiency, dynamic and reliability for a successful participation in motorsports. After the success in the 2009 edition the engagement has been continued also in 2010, this time exclusively with CNG vehicles. Focusing on the CO₂ emission, reclusively the higher hydrogen content of methane which represents the main component of NG leads to a CO₂ reduction during the combustion of about 20% compared to gasoline. Thanks to the laminar burning speed of methane which is approximately maximal for a stoichiometric mixture, CNG engines do not require a mixture enrichment at WOT operating conditions, so that the fuel consumption decreases. In addition the very high knock-resistance of natural gas allows a further efficiency increasing by using a higher compression ratio. Conclusively the CO₂ reduction of the CNG version ranges from ca. 30% using natural gas up to 80% for bio-gas. On the other hand gas injection in the intake manifold causes a loss of charge due to both the low mass density of natural gas and the absence of heat of vaporization. The latter also produces a temperature level of the exhaust gas at the turbine which is more critical. Another drawback of CNG engines is the homogenization of the air-fuel mixture. This process is more critical because even high gas velocities at the injector nozzle cause a very low fuel penetration. Therefore, mixture homogenization or stratification depends much more on charge motion as usual for liquid fuels. For this reason the design of the intake system and the combustion chamber is a crucial step for the optimization of a CNG engine. In this paper the engine development process has been performed mainly in a virtual context. The implementation of an innovative 3D-CFD tool (QuickSim) that has permitted full-engine simulations of this turbocharged CNG race-engine has allowed, within short time (few months), to remarkably increase the engine performance. The virtual engine development process has started with the 3D-CFD analysis of the fluid motion of the basic engine. Based on this analysis, many engine-design modifications have then been virtually tested, so that at the end only a few promising solutions have been "concretely" realized and tested at the test bench. Since the results at the test bench have finally confirmed the expectations from the simulation results, following this procedure it has been definitively possible to speed up the engine development process even by limiting the budget.
Chiodi, Marco, Ferrari, Alessandro, Mack, Oliver, Bargende, Michael, Wichelhaus, Donatus
Virtual Set-up of a Racing Engine for the Optimization of Lap Performance through a Comprehensive Engine-Vehicle-Driver Model2011-24-01419/11/2011
In Motorsports the understanding of the real engine performance within a complete circuit lap is a crucial topic. On the basis of the telemetry data the engineers are able to monitor this performance and try to adapt the engine to the vehicle's and race track's characteristics and driver's needs. However, quite often the telemetry is the sole analysis instrument for the Engine-Vehicle-Driver (EVD) system and it has no prediction capability. The engine optimization for best lap-time or best fuel economy is therefore a topic which is not trivial to solve, without the aid of suitable, reliable and predictive engineering tools. A complete EVD model was therefore built in a GT-SUITE™ environment for a Motorsport racing car (STCC-VW-Scirocco) equipped with a Compressed Natural Gas (CNG) turbocharged S.I. engine and calibrated on the basis of telemetry and test bench data. The driver is simulated by means of a "position based" control in order to determine the braking points at each corner by itself and regulate the braking/accelerating intensity. By means of simplified vehicle dynamics and a complete engine flow dynamic modeling the behavior of the overall system during the lap can be analyzed and different scenarios simulated. In particular the focus is concentrated on the real operating conditions of the powertrain unit, which can be eventually combined also with energy recovery systems (e.g., KERS and TERS). In the proposed EVD model each technical element (Engine, Vehicle) is distinct and can be interchangeable. For example, the engine can be virtually optimized and the influence of different technical configurations or engine mapping on the global performance can be investigated. The aim is to create modeling solutions which are compatible with the short development time of motorsports and thus to maintain acceptable CPU-time. As results of the proposed simulations show, spark advance, fuel injection and direct control of the waste-gate (WG) are parameters which can influence the overall performance for the adopted racing vehicle.
Ferrari, Alessandro, Chiodi, Marco, Bargende, Michael, Roberti, Paolo, Millo, Federico, Wichelhaus, Donatus
New TOYOTA 4.8L V10 Petrol High Performance Engine for Lexus LFA2011-01-20248/30/2011
Achieving the speed and performance of a true supercar was merely the starting point of this development. In addition, the development also focused on achieving emotive performance attributes to enhance driver appeal. For this the engine was developed to assist a vehicle handling provides unsurpassed response, the creating a feeling of infinite acceleration potential, response is instantaneous and based on close understanding of driver's reactions and Awe inspiring sound is providing. It meets the latest emission standard Euro V and achieves good fuel consumption with a wide range stoechiometric air fuel ratio, till speeds up to 240km/h.
Okamoto, Takamitsu, Kawamura, Hiroshi, Tsukamoto, Keisuke, Nagai, Masakatsu, Uchida, Takahiro, Maruyama, Heiji
Anti- Combustion Deposit Fuel Development for 2009 Toyota Formula One Racing Engine2011-01-19838/30/2011
Toyota participated in Formula One1 (F1) Racing from 2002 to 2009. As a result of the downturn in the world economy, various engine developments within F1 were restricted in order to reduce the cost of competing in F1. The limit on the maximum number of engines allowed has decreased year by year. Toyota focused on the engine performance deterioration due to the combustion chamber deposits. In 2009, Toyota was successful in reducing around 40% of the deterioration by making combustion chamber cleaner in cooperation with ExxonMobil. This contributed to good result of 2009 F1 season for Toyota, including two second place finishes.
Takeuchi, Kazuo, Pfeilmaier, Peer, Esaki, Yasuo, Choi, Eugine
A Way towards Remarkable Reduction of Co2-Emissions in Motorsports: The CNG-Engine2011-37-00066/9/2011
Until a few years ago the discussion of reduction of CO₂ emissions was completely out of place in motorsports. Nowadays, also in this field, car manufacturers want to investigate different approaches towards a more responsible and sustainable concept. For this target an interesting and feasible solution is the use of methane as an alternative fuel. At the 2009 edition of the 24-hour endurance race of the Nürburgring the Volkswagen Motorsport GmbH, in addition to vehicles powered by gasoline engines, introduced two vehicles powered by turbocharged CNG engines. The aim was to prove that also an "environment-friendly" concept is able to provide the required efficiency, dynamic and reliability for a successful participation in motorsports. After the success in the 2009 edition the engagement has been continued in 2010; this time exclusively with CNG vehicles. This paper aims to give an overview on the potentiality of a CNG engine for race applications starting from thermo-dynamical considerations up to a concrete comparison with the gasoline engine from which it has been derived. The availability of experimental data and the use of modern simulation tools widen the possibility for studying different scenarios for performance development.
Chiodi, Marco, Ferrari, Alessandro, Mack, Oliver, Bargende, Michael, Wichelhaus, Donatus
Advanced Diesel Engine 42% Brake Thermal Efficiency Technology Demonstrators2011-01-01214/12/2011
Battlefield delivered fuel (jet and diesel) with required security, storage, transport, and dispensing equipment is estimated to cost $418/gallon [ 1 ], thus the need for very fuel efficient light weight engines for repower and future vehicles is critical. The U.S. Army RDECOM TARDEC Small Business Innovative Research (SBIR) Program funded Advanced Engines Development Corporation (AED) for the exploration, development and application of advanced diesel engine technologies and to incorporate these technologies into demonstrator engines, a 4-cylinder and V-8's. AED based these demonstrators on current production GM gasoline engine diesel conversions employing commercial-off-the-shelf (COTS) advanced diesel systems and engine components. Using an iterative process of analysis, design, fabrication, and dyno testing a 2.2/2.4 liter displacement and 6.5 liter engines incorporating the latest technology in: high pressure common-rail fuel injection; high combustion charge air density utilizing a supercharger and turbocharger in-series with inter- and after-cooling; and a highly turbulent combustion system were developed. A series of three increasingly advanced 2.2/2.4 liter diesel engines were built and dyno tested. All engine systems and operations were electronically managed and programmable. The performance goals of: 42% brake thermal efficiency, 18-25 bar BMEP; and specific heat rejection to coolant and oil of 16-21Btu/hp-min were met or exceeded in fully operational lightweight high power density engines. These developed advanced diesel technologies were incorporated into two V-8 series engines, one based on the 6.5L HMMWV engine and the other on GM LS high performance gasoline V-8's. These replacement engines could upgrade the HMMWV and other applications through the modernization/recapitalization programs to have a military fleet of high powered, very fuel efficient diesel engines.
Hirsch, Nicholas R., Mekari, Milad H.
Real-Time Combustion Phase Optimization of a PFI Gasoline Engine2011-01-14154/12/2011
Combustion control is assuming a crucial role in reducing engine tailpipe emissions and maximizing performance. The number of actuations influencing the combustion is increasing, and, as a consequence, the control parameters calibrations is becoming challenging. One of the most effective factors influencing performance and efficiency is the combustion phasing: gasoline engines Electronic Control Units (ECU) manage the Spark Advance (SA) in order to set the optimal combustion phase. SA optimal values are usually determined by means of calibration procedures carried out on the test bench by changing SA values while monitoring Brake and Indicated Mean Effective Pressure (BMEP, IMEP), Brake Specific Fuel Consumption (BSFC) and pollutant emissions. The effect of SA on combustion is stochastic, due to the cycle-to-cycle variation: the analysis of mean values requires many engine cycles to be significant of the performance obtained with the given control setting. Usually, the optimization process is carried out off-line, based on the data sampled on the test-bench. This paper presents the application of a new calibration concept, with the objective of improving the robustness of performance analysis, while reducing the test time. The approach is applied to a simple calibration problem, where a single input factor (SA) is tuned taking into account two issues: IMEP maximization and knock limitation. The paper shows how the methodology can be extended to multiple objective and multi-input optimization problems. The methodology is based on the observation that, due to cycle-to-cycle variation, the combustion phasing, represented by the 50% Mass Fraction Burned (MFB50) parameter, changes continuously, even with a fixed SA. The IMEP changes accordingly, forming a typical parabola distribution in the plane IMEP-MFB50. The optimization could then be carried out by choosing SA values maintaining the scatter around the vertex. Unfortunately the distribution shape is slightly influenced by heat losses (i.e., by SA): this effect must be taken into account in order to avoid over-advanced calibrations. The synthesis of this core-concept allows giving a contribution to a cost function, used to drive SA variations; another contribution comes from the knock intensity level. The final objective is to minimize the cost function absolute value, leading to the maximum IMEP achievable with tolerable knock intensity. The optimization process is carried out with an original approach: the cost function is by all means the error input of a PID (Proportional Integer Derivative) controller that, by definition, is intended to reduce the error, i.e., the cost function, thus performing the optimization. The methodology has been developed and tested off-line using data referring to three different PFI gasoline engines, then it has been implemented in Real-Time. The combustion control system used for the implementation performs a cycle-to-cycle combustion analysis, evaluating the combustion parameters necessary to calculate the target SA; the target SA is then actuated by the ECU. The approach proved to be efficient, reducing the number of engine cycles necessary for the calibration to less than 1000 per operating condition.
Corti, Enrico, Forte, Claudio
Development of a One-Dimensional Engine Thermal Management Model to Predict Piston and Oil Temperatures2011-01-06474/12/2011
A new, 1-D analytical engine thermal management tool was developed to model piston, oil and coolant temperatures in the Ford 3.5L engine family. The model includes: a detailed lubrication system, including piston oil-squirters, which accurately represents oil flow rates, pressure drops and component heat transfer rates under non-isothermal conditions; a detailed coolant system, which accurately represents coolant flow rates, pressure drops and component heat transfer rates; a turbocharger model, which includes thermal interactions with coolant, oil, intake air and exhaust gases (modeled as air), and heat transfer to the surroundings; and lumped thermal models for engine components such as block, heads, pistons, turbochargers, oil cooler and cooling tower. The model was preliminarily calibrated for the 3.5L EcoBoost™ engine, across the speed range from 1500 to 5500 rpm, using wide-open-throttle data taken from an early heat rejection study. The model accurately predicts oil sump temperatures, coolant engine-out temperatures and peak piston temperatures for steady-state, WOT conditions, across the speed range. Also, the model predicts warm-up oil sump temperatures within the experimental test data variation, and predicts warm-up coolant temperatures within ± 5°F. With further calibration, it is expected that this model may provide design guidance to determine the effects of piston squirter oil flow rates on piston temperature and on cold-start oil warm-up temperatures. The current model uses experimental coolant energy to estimate the combustion energy input. To enhance the predictive capability, this model should be further calibrated using data from additional engine configurations and from piston heat transfer engine or bench tests. Additionally, an in-cylinder heat release model should be included as a replacement for the experimental coolant energy input.
Sangeorzan, Brian, Barber, Eva, Hinds, Brett
Exploring the Advantages of Atkinson Effects in Variable Compression Ratio Turbo GDI Engines2011-01-03674/12/2011
The Atkinson cycle engine is basically an engine permitting the strokes to be different lengths for improved light loads fuel economies. Variable compression ratio is the technology to adjust internal combustion engine cylinder compression ratio to increase fuel efficiency while under varying loads. The paper presents a new design of a variable compression ratio engine that also permits an expansion ratio that may differ from the compression ratio therefore generating an Atkinson cycle effect. The stroke ratio and the ratio of maximum to minimum in-cylinder volumes may change with load and speed to provide the best fuel conversion efficiency. The variable ratio of maximum to minimum in-cylinder volumes also improves the full load power output of the engine. Results of performance simulations are proposed for a gasoline engine 2 Litres, in-line four, turbocharged and direct injection showings significant fuel savings during light and medium loads operation as well as improvement of full load output and fuel efficiency.
Boretti, Alberto, Scalzo, Joseph
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