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Guidelines for the Integration of Electronic Engine Control Systems for Transport Category (Part 25) and General Aviation (Part 23) AircraftAIR5924B (Current)11/26/2025
This SAE Aerospace Information Report (AIR) provides methodologies and approaches that have been used to install and integrate full-authority-digital-engine-control (FADEC) systems on transport category aircraft. Although most of the information provided is based on turbofan engines installed on large commercial transports, many of the issues raised are equally applicable to corporate, general aviation, regional and commuter aircraft, and to military installations, particularly when commercial aircraft are employed by military users. The word “engine” is used to designate the aircraft propulsion system. The engine station designations used in this report are shown in Figure 1. Most of the material concerns an Electronic Engine Control (EEC) with its associated software, and its functional integration with the aircraft. However, the report also addresses the physical environment associated with the EEC and its associated wiring and sensors. Since most of today’s transport category engines use dual-channel full-authority digital engine control (FADEC) systems, this is the configuration which is addressed. A typical FADEC system configuration is shown in Figure 2.
E-36 Electronic Engine Controls Committee
Design Considerations for Enclosed Turbofan/Turbojet Engine Test CellsAIR4869B (Current)2/1/2021
This SAE Aerospace Information Report (AIR) has been written for individuals associated with the ground-level testing of large and small gas turbine engines and particularly for those who might be interested in upgrading their existing or acquiring new test cell facilities.
EG-1E Gas Turbine Test Facilities and Equipment
Design Considerations for Enclosed Turbofan/Turbojet Engine Test CellsAIR4869A (Historical)10/22/2020
This SAE Aerospace Information Report (AIR) has been written for individuals associated with the ground-level testing of large and small gas turbine engines and particularly for those who might be interested in upgrading their existing or acquiring new test cell facilities.
EG-1E Gas Turbine Test Facilities and Equipment
Dimensional Optimization of Key Parameters Using DoE Technique to Achieve Better NO X Emission Values in Mass Production of Single Cylinder Small Diesel Engines for 3 Wheeler Applications2020-01-13564/14/2020
Oxides of Nitrogen (NOx) emissions are considered as among the most harmful emissions globally having a direct influence on human beings and the environment. This work deals with a strategy to arrive at achieving lower NOx values consistently in mass production of single cylinder automotive diesel engines meeting BS IV Emission standards using the DoE technique for dimensional optimization of critical parameters. Catalytic converters and particulate filters are mostly used as after - treatment devices for compression Ignition (CI) engines for bringing down the limits (Values) of the pollutants from the tail pipes. But the real ingenuity lies in achieving the same effect through optimization of in - cylinder combustion. Optimization of the critical factors like Nozzle Tip Protrusion (NTP), Static Injection Timing (SIT), Bumping Clearance (BC) and Swirl Number (SN) are considered as the most important engine design parameters for ensuring the optimum combustion which help release of minimal harmful pollutants. In this work, a standard L9 Orthogonal Array (OA) table was used in designing experiments for a study of the interactive model between the said factors and their levels to achieve consistently lower NOx emission values. The design specification of NTP considering the tolerance limit was set between 3.0 mm to 3.30 mm and similarly SIT, BC and Swirl value were set between 0.19 mm to 0.27mm, 0.65mm to 0.75 mm and 2700 rpm to 2800 rpm respectively. Tests were conducted on the basis of standard OA table and the corresponding NOx emissions were measured. It is found that, NTP of 3.2 mm, SIT of 0.19 mm, BC of 0.70 mm and Swirl Rate of 2775 rpm were seen yielding the least NOx emissions. Statistical observations showed the above mentioned combination exhibiting a reduction of NOX achieved with respect to the design specification as 22% and the variation of NOx between engines as 1.1%.
Ramalingam, Jaganathan, B, Prabakaran, Nandagopal, Sasikumar, Venkatesan, Hariram, Mayakrishnan, Jaikumar
Internal Combustion Engines - Piston VocabularyJ2612_202002 (Current)2/18/2020
This SAE standard defines the most commonly used terms for pistons. These terms designate either types of pistons or certain characteristics and phenomena of pistons.
Piston and Ring Standards Committee
Influence of Zn, Mo, P, S-contained Engine Oil Additives on Abnormal Combustion in a Spark Ignition Engine2019-32-05861/24/2020
A Spark Ignition Engine has some kinds of problem to be solved over many years, one of them is abnormal combustion; Low-speed pre-ignition (LSPI) under low-speed, high-load driving conditions for vehicle, and pre-ignition under longterm operation without cleaning a combustion chamber for gas cogeneration. As a cause for abnormal combustion, engine oil droplets diluted by liquid fuel and peeled combustion deposits delivered from engine oil are proposed. In this study, experiments were conducted focusing on engine oil additives having different chemical structure and abnormal combustion behavior. A four-stroke side-valve single cylinder engine that allowed in-cylinder visualization of the combustion flame was used in the experiments. The experimental results showed that the influence of DTC additive on abnormal combustion is small and the zinc component contained in the DTP additives had the effect of advancing the autoignition timing.
Izako, Takuya, Iijima, Akira, Kusumoto, Tatsuya, Utaka, Toshimasa
Engine Exhaust Noise Optimization Using Sobol DoE Sequence and NSGA-II Algorithms2019-01-14836/5/2019
Exhaust muffler is one of the most important component for overall vehicle noise signature. Optimized design of exhaust system plays a vital role in engine performance as well as auditory comfort. Exhaust orifice noise reduction is often contradicted by increased back pressure and packaging space. The process of arriving at exhaust design, which meets packaging space, back pressure and orifice noise requirements, is often manual and time consuming. Therefore, an automated numerical technique is needed for this multi-objective optimization. In current case study, a tractor exhaust system has been subjected to Design of Experiments (DoE) using Sobol sequencing algorithm and optimized using NSGA-II algorithm. Target design space of the exhaust muffler is identified and modeled considering available packaging constrain. Various exhaust design parameters like; length of internal pipes, location of baffles and perforation etc. are defined as input variables. Performance objective of back pressure and sound pressure level has also been defined in simulations workflow. Exhaust orifice noise has been reduced with significant reduction in overall simulations time. The optimal design is achieved satisfying all constrains leading to notable productivity improvement.
Sethi, Ishwinder Pal Singh, Nene, Devendra, Shivajirao Patil, Anand
Experimental Studies on Liquid Phase LPG Direct Injection on a Two-Stroke SI Engine03-12-03-00235/31/2019
Directly injecting fuel in two-stroke spark-ignition (2S-SI) engines will significantly reduce fuel short-circuiting losses. The liquid phase liquefied petroleum gas (LPG) DI (LLDI) mode has not been studied on 2S-SI engines even though this fuel is widely used for transportation. In this experimental work a 2S-SI gasoline-powered engine used on three-wheelers was modified to operate in LLDI mode with an electronic engine controller. The influences of injection pressure (IP), end of injection (EOI) timing, location of the spark plug, and type of injector on performance, combustion, and emissions were studied at different operating conditions. EOI close to bottom dead center with the spark plug located near the exhaust port was the most suitable for the LLDI mode which significantly enhanced the fuel trapping efficiency and improved the thermal efficiency. At 70% throttle condition the brake thermal efficiency increased from 19% to 25.6% and there was an 87% reduction in hydrocarbon (HC) emission compared to liquid phase LPG manifold injection. The use of multi-hole injector extended the maximum power output due to better in-cylinder mixture formation, whereas the single-hole injector extended the lean operating limit. LLDI has potential to improve the performance of small two-stroke engines significantly.
Dube, Adwitiya, Vivekanand, M., Ramesh, A.
Increased 2-Wheeler Development Efficiency by Using a New Dedicated Test System Solution2019-26-03481/9/2019
Fuel consumption is the most important contributor to the total cost of ownership for mass produced motorcycles. Therefore, best fuel economy is one main influencing criteria for a decision to purchase motorcycles. Furthermore, increasingly stringent emission legislations limit and additional OBD requirements must be fulfilled. A new combined test approach has been developed that minimizes accuracy losses in the development process which compensates for the variability of driving behavior in the chassis dyno environment. An engine testbed combined with a belt drive transmission enables operation in single engine or in Powerpack (i.e. internal combustion engine including transmission) configuration as well as under steady state or dynamic operating mode. Since the belt drive transmission is integrated in the test rig, realistic inertia situation for the single engine operating test configuration is ensured. Furthermore, a vehicle- and continuous variable transmission (CVT) model, which is implemented in the testbed automation system, enables the simulation of real hardware components. This means that vehicle measurements usually only taken on the chassis dyno can be shifted to the engine testbed in early stages of development. Tests can be carried out even before first vehicle prototypes are available, as long as simulation models can be characterized and parametrized sufficiently. In addition, as a key advantage, measurements done on the engine testbed including the transmission and vehicle simulation are fully repeatable. It has also been observed that development target verification is more accurate compared to the previous procedure. All in all, the new solution incorporating latest testing tools, methodologies and technology, increases the development efficiency tremendously.
Mayrhofer, Harald, Hochmann, Gerald, Berger, Arnold
An Investigation with Mechanical Supercharging as Boosting Solution on Less than 0.5 Liter Single Cylinder Diesel Engine towards Bharat Stage VI Emission Development2019-26-01521/9/2019
Small single & two cylinder diesel engines, still have primitive technical design features and extensively used in India and various Asian countries to power small and light motor vehicles viz., three wheelers, light duty four wheelers. These vehicles have become inevitable for the transport for both urban and rural areas. Vehicles with small single & two cylinder engines have high market demand in commercial transport due to restrictions on entry of Heavy Commercial Vehicles (HCV) in congested cities roads. Due to ever rising market demand for higher power and torque requirement along with better fuel economy, vehicle manufacturer are developing high Brake Mean Effective Pressure (BMEP) engines or replacing single cylinder engine by two cylinder engine, similarly two cylinder engine by three cylinder engines. Further, these engines should meet the present and forthcoming stringent emission limits. Single cylinder and two cylinder small diesel engines are widely used in various applications like Light Commercial Vehicle (LCV), power generation, three wheelers, agricultural machines and small house-hold applications in India as well as other Asian countries. Therefore simple mechanically controlled components are used for these engines which make them simple in operation with low maintenance and cost effective. Several studies & research work so far conducted on these small single engine have revealed that, successful & economically acceptable turbocharging of single cylinder diesel engine is not yet achieved. This is due to its phase mismatch between intake and exhaust stroke timings, long gap between two exhaust stroke and continuous flow of exhaust gas to drive the turbine wheel efficiently. This paper addresses the problems through mechanical supercharging. For this research work, a small 0.4 liter, three wheeler (3W), naturally aspirated, air-cooled, single cylinder DI diesel engine, equipped with mechanical fuel injection system, is used. A roots type supercharger, driven mechanically from a drive pulley directly mounted on crankshaft, is used for boosting the engine. Experiments were conducted with various engine parameters, settings and step-up ratios of the drive pulley. The results show an observed increase in engine power more than 20 % throughout the full load curve and favorable emission levels with respect to the base BS III compliant single cylinder engine. The experimental outcomes and reviews which are required to arrive at adequate boosting to enhance the performance & emissions of the engine are reported.
Bhat, Prasanna, Pawar, Narendra, Narwade, Dadarao, Nalawade, Santosh, Gayen, Hirak Jyoti, Marathe, Neelkanth, Chopane, Sanjay Parshuram
Design Considerations for Enclosed Turboshaft Engine Test CellsAIR4989A (Current)11/21/2018
This SAE Aerospace Information Report (AIR) developed by a broad cross section of personnel from the aviation industry and government agencies is offered to provide state-of-the-art information for the use of individuals and organizations designing new or upgraded turboshaft engine test facilities.
EG-1E Gas Turbine Test Facilities and Equipment
Development of a Climate and Altitude Simulation Test Bench for Handheld Power Tools2018-32-003310/30/2018
A climate and altitude conditioning test bench was developed at the Institute of Energy Efficient Mobility (IEEM) of Karlsruhe University of Applied Sciences to evaluate the overall sustainability of using innovative biofuels in handheld power tools such as chainsaws, trimmers and blowers under any typical operating condition worldwide. The 6 m3 hermetically sealed and thermally insulated test chamber is large enough to fit the entire power tool. A two-stage refrigeration system with intake air drying and electric heating allows for realistic temperature conditions to be set in the test chamber, ranging from arctic cold to tropical heat (-28 to 45 °C). Altitudes of up to 3500 m above sea level can be simulated using a throttle valve at the inlet of the chamber and a pressure-controlled rotary screw compressor positioned downstream the test chamber outlet. The air-cooled engines to be tested are fully exposed to the ambient conditions inside the test chamber, are able to aspirate the conditioned combustion air freely and release both exhaust gas and waste heat into the chamber environment. In order to control the power tool’s operation when the chamber is closed, an adaptive remote control system was specially developed. It enables automatic engine start-up by cable pull (e.g. for cold start testing), engaging the choke valve as well as operating the throttle lever automatically. This paper discusses the development process, the design, the operating limits of the climate and altitude simulation test bench as well as first tests on the reproducibility of the automatic start procedure, particularly important for future cold start investigations.
Martel, Artur, Scholl, Fino, Weierter, Dennis, Kettner, Maurice
Study on Knocking Characteristics for High-Efficiency Operation of a Super-Lean Spark Ignition Engine2018-32-000210/30/2018
This study investigated the influence of EGR and spark advance on knocking under high compression ratio, ultra-lean mixture and supercharged condition using premium gasoline as a test fuel. A high-compression ratio, supercharged single cylinder engine was used in this experiment. As a result, the period from ignition to autoignition was prolonged. In addition, knock intensity was drastically reduced. In other words, it is inferred that by combining an appropriate amount of EGR and spark advance, high efficiency operation avoiding knocking can be realized.
Nishiyama, Takeshi, Agui, Keito, Togawa, Masaaki, Saito, Masanori, Tanabe, Mitsuaki, Iijima, Akira
CFD Analysis of a Port Fuel Injection IC Engine to Study Air-Fuel Mixture Preparation and Its Impact on Hydrocarbon Emission and Mixture Homogeneity in Combustion Chamber2018-32-000510/30/2018
At part load conditions, effective utilization of fuel is critical for drivability of an IC engine driven automobile, with minimum emissions and fuel consumption. It becomes cardinal to study the mixture preparation in engines to understand the injection strategy that helps in achieving the prime objectives of lower emission and reliable operation. To add to the complexity of the problem being studied, the injection phenomenon is rapid, turbulent, multi-phase, two-way coupled (where the continuous phase affects the droplets and vice versa) and involves turbulence length scales and time scales, few orders of magnitude lower compared to the characteristic length in the turbulence integral scale. A methodology is developed in Star-CD and ES-ICE to simulate the mixture preparation in Port Fuel Injection (PFI) engines. High quality mixture preparation which is essential for combustion stability and lower emissions is aimed at part load conditions which constitute the majority of driving cycle. This methodology is helpful to understand and solve the injection timing development issues and in improving the combustion stability and lowering the emissions. The fuel injection parameters have been studied in detail both experimentally and numerically in a specialized spray chamber. The fuel injection parameters are correlated to the source of injection to obtain similar fit of droplet distribution profile obtained experimentally. The parameters like - injection timing, injection location and injection pressure can be efficiently optimized through this methodology for efficient mixture formation. Extensive studies have been done on different injection timing in order to reduce the wall film thickness and fuel short circuit losses and to increase the overall evaporation rate of fuel droplets by increasing the residence time. Two injection timing strategies namely - open valve injection and closed valve injection have been analyzed to understand the effect of fuel short circuit losses and its impact on HC (hydro-carbon) emissions. It is observed that, open valve injection has lower short circuit losses compared to closed valve injection, which is experimentally verified and thus has a great significance in reducing the HC emissions. However, open valve injection comparatively affects the in-cylinder charge homogeneity and standard deviation of equivalence ratio. This paper also discusses on the strategies that have been undertaken to achieve best-in-cylinder homogeneity with an adverse effect on increased fuel film thickness on the port walls. Efforts are made to optimize the injection timing and location for best mixture formation in production automotive vehicles and in extending the methodology for the corresponding emission prediction. Being a computationally intensive problem with an additional complexity of moving mesh, opens an opportunity for parallel performance study. Parallel performance study shows that the methodology proposed above uses a Message Passing Interface (MPI) and shows a good scale up for 2-16 cores, above which it saturates. Multi-cycle analysis is carried out to understand the variation in Air-Fuel ratio homogeneity and Coefficient of variation of Indicated Mean Effective Pressure (IMEP) which provides a fundamental vista on the transient behavior of the spray dynamics.
G B, Arivazhagan, Garg, Manish
Horsepower Correction FormulaeARP2C (Current)8/9/2018
This document discusses formulae considered applicable to aircraft engines having integral supercharging without aftercooling, and using gasoline introduced at the entrance to the supercharger or directly into the cylinders. Such engines are normally designated as single and two speed engines. Correction formulae for engines having two stage or exhaust turbo supercharging will not be discussed. Corrections for engines having a high degree of integral supercharging will be discussed in general terms only and no specific formulae will be presented. The correction formulae and methods listed are empirical and subject to error due to conditions beyond the scope of known corrections. Usage has indicated, however, that the correction formulae listed will provide a satisfactory approximation of power output under standard conditions.
E-25 General Standards for Aerospace and Propulsion Systems
Bike with Modified Steering System to Assist People with Forearm Disability2018-28-00627/9/2018
Individuals with mobility impairments are people who have lost their functionality of leg and hand due to birth, diseases or accidents. Various commercial bike designs are existing in the market for bike riders with disability in their legs designed with dummy rear axle. But no designs exits for bike riders with disability in their hands which is being available in market. To ride a bike steering, brake and acceleration controls has to be provided by an alternate method. It was proposed to develop a bike for person with disability in their hand. The design of the bike and in particular steering system was done using of Autodesk Inventor software and analysed using ANSYS workbench to assess the structural integrity of the design. The design was transformed in to a complete working prototype and found to be working satisfactory.
Mathiyalazhan, Vivekananthan, Elsen, Renold
Engines, Aircraft, Reciprocating, General Specification ForAS25109A (Current)6/18/2018
This specification covers standard requirements for reciprocating aircraft engines.
E-25 General Standards for Aerospace and Propulsion Systems
Exploring the Potential of Combustion on Titan01-11-01-00024/7/2018
Significant attention has been focused on Mars due to its relative proximity and possibility of sustaining human life. However, its lack of in-situ sources of energy presents a challenge to generate needed energy on the surface. Comparatively, Titan has a nearly endless source of fuel in its atmosphere and lakes, but both are lacking in regards to their oxidizing capacity. The finding of a possible underground liquid ammonia-water lake on Titan suggests that oxygen might actually be within reach. This effort provides the first theoretical study involving a primary energy generation system on Titan using the atmosphere as a fuel and underground water as the source for the oxygen via electrolysis from wind generated electricity. Thermodynamic calculations and use of chemical kinetics in a zero-dimensional Homogeneous Charge Compression Ignition (HCCI) engine model demonstrate that is indeed possible to operate an internal combustion engine on the surface of Titan while providing heat for terraforming and human activities. Subsequent terraforming estimates illustrate that while the potential for energy and heat exists, the amount of needed hardware is largely impractical. However, the findings may stimulate further curiosity by others to look towards outer space and imagine what might be possible.
Depcik, Christopher
Thermal Analysis and Experimental Investigations on the Effect of Thermal Barrier Coating on the Behavior of a Compression Ignition Engine Operated with Methyl Esters of Waste Cooking Oil2018-01-06634/3/2018
One of the globally challenging issues today is Waste Utilization. The excessive accumulation of waste has created an uncomfortable pressure on not, just the habitant but on the environment as well. As a small step forward in contributing towards minimizing waste disposal, this study attempts to address the problem raised due to the disposal of waste cooking oil. Researchers found that Waste Cooking Oil (WCO) has a very good potential as a fuel for compression ignition engine and was therefore selected for this study. In the first phase of the work, behaviour of the test engine was studied with neat WCO at different power outputs. As the first modification, neat WCO was converted in to its methyl ester and tested in the same engine. Next, combustion chamber parts like piston and cylinder head, inlet and exhaust valves were coated with Thermal Barrier Coating (TBC) and engine behaviour was studied. To make the study more interesting a thermal- stress analysis was done on the engine piston to examine the impact of coating on engine performance. Results claimed that Brake Thermal Efficiency (BTE) of the engine operated with methyl esters of WCO showed marked improvement as compared to its neat form. However, the smoke emission was found to be still on the higher range with methyl ester of WCO. Engine results with thermal barrier coating reported improved BTE as compared to the earlier case. Interestingly, all the carbon based emissions were drastically reduced at the cost of increased oxides of nitrogen emissions. It was also found from the analysis that the surface temperature of the coated surface was higher than that of the uncoated surface. Thus, this work concludes that WCO in the form of its methyl ester can be used effectively in the compression ignition engine with a slight modification of the combustion chamber parts.
Elumalai, Sangeethkumar, Mayakrishnan, Jaikumar, Nandagopal, Sasikumar, Raja, Selvakumar, Mukherjee, Sudip
A Comprehensive CFD Method for Thermal Performance Evaluation of a Scooter Type Motorcycle and Its Application2017-32-003611/5/2017
Thermal management is of vital importance in the development of a scooter type motorcycle (two-wheeler). Traditionally the thermal management development of a two-wheeler is done through experimental methods, or using sub-system level CFD models. In current work, a comprehensive, complete vehicle, three-dimensional CFD model has been developed to assess thermal performance of the scooter and its sub-systems. The model can predict thermal performance in different operating conditions, such as, wide open throttle, idling and key-off. A typical thermal interaction in engine happens through metal contact conduction, air cooling and oil flow path in the engine. The model can capture the sub system interaction, such as, an interaction between the cooling system and engine cabin. Modeling oil is computationally expensive, as it involves complex physics modeling such as multiphase flow. An energy balance based new sub-model is added to the CFD model which can predict the engine oil temperature without modeling the oil flow inside the oil sump. A good correlation for this new sub-model has been achieved between CFD model and on-road experimental values. The air and solid temperatures at different locations of engine and vehicle from CFD model has been validated with the on-road measurement. The time to build and evaluate a design is being reduced to one fifth with this new method, and incorporating any design change in the model and its evaluation through CFD is reduced to one tenth. Finally, a case-study has been presented to demonstrate how the model has been used in product development process by capturing various failure modes early in the product development process and resolution of these failure modes using model and test.
Kumar, Gundavarapu V S, Suresh, M, Garg, Manish
Innovative Carburetor Design with Dynamic Air to Fuel Ratio (AFR) Control for Improved Fuel Economy and Reduced Emissions2017-32-000311/5/2017
An innovative carburetor system has been developed for use in single cylinder small engines. The carburetor has been implemented on a 79cc 4 stroke portable gasoline generator for the purposes of illustrating its effect in reducing emissions, engine deposits and improving fuel economy without re-jetting the carburetor. This method of carburetion dynamically tunes the venturi effect in the carburetor, allowing for air density, fuel viscosity and fuel type compensation for optimal AFR. Modified and stock generators were tested at various power levels, elevations and temperatures to simulate operational environments. The improvements in emissions and fuel consumption will be presented. In addition, the system has been designed as a bolt-on, low cost alternative to an EFI method of complying with emissions regulations for existing small engine applications.
Simmons, Timothy C., Markoski, Larry J.
A Model Based Approach for Generating Pre-Calibration Data for Two-Wheelers2017-32-003811/5/2017
Today, 99% of the two wheelers in India operate with carburetor based fuel delivery system. But with implementation of Bharath Stage VI emission norms, compliance to emission limits along with monitoring of components in the system that contributes towards tail pipe emissions would be challenging. With the introduction of the OBD II (On-Board Diagnostics) and emission durability, mass migration to electronically controlled fuel delivery system is very much expected. The new emission norms also call for precise metering of the injected fuel and therefore demands extended calibration effort. The calibration of engine management system starts with the generation of pre-calibration dataset capable of operating the engine at all operating points followed by base calibration of the main parameters such as air charge estimation, fuel injection quantity, injection timing and ignition angles relative to the piston position. Finally, the vehicle calibration is executed keeping drivability and compliance to legislative norms as prime requirements. The quality of the pre-calibration data and base calibration decides the number of iterations required to arrive at the final dataset that meets the emission targets. Currently, the pre-calibration data is ported from datasets belonging to engines of similar displacement calibrated before; as a result of which the data do not fit well at all engine operation points. This paper elucidates a model based approach that generates pre-calibration dataset closest in match to the dataset obtained after base calibration at engine dynamometer using limited measurement logs from the engine. This is achieved through modelling the system using identified geometrical information of the engine, intake and exhaust systems and then introducing the physics of engine operation into it. Using the geometrical information, MATLAB based models are built to calculate the critical parameters like pressure drop across air filter, resonant frequency of the Helmholtz resonator in the intake path, throttle and valve flow coefficients and friction torque. The output of these individual MATLAB models are then fed into a predictive model that estimates the combustion parameters. These in turn serve as inputs to a one dimensional engine model built in GT Suite which then predicts the air charge entering the cylinder, optimum ignition angles, brake torque and exhaust gas temperature at the manifold. A case study was done with a 200cc air cooled engine as reference, for which the outcome of the GT Suite model is compared against the actual calibration dataset. The model is found to predict the air-charge at an accuracy of 85%, optimum ignition angles within ± 4.5° CA, brake torque at 85% accuracy and exhaust temperatures within ±20° C.
Palackal, Rose Mary Simon, Kartha, Balagovind Nandakumar, Ramachandran, Karthikeyan, Vijaykumar, Srikanth, Reddemreddy, Pramod
Covers, Aircraft Components, General Requirements ForAS5778 (Current)11/3/2017
This specification covers general requirements for covers intended to protect the following aircraft parts: Cockpit Fuselage Canopy Engine Armament Propeller or Rotor Miscellaneous
AGE-4 Packaging, Handling and Transportability Committee
A Comparison of Conventional and Reactivity Controlled Compression Ignition (RCCI) Combustion Modes in a Small Single Cylinder Air-Cooled Diesel Engine2017-01-236510/8/2017
Reactivity controlled compression ignition (RCCI) is one of the most promising low temperature combustion (LTC) strategies to achieve higher thermal efficiencies along with ultra low oxides of nitrogen (NOx) and particulate matter emissions. Small single cylinder diesel engines of air-cooled type are finding increasing applications in the agriculture pump-set and small utility power generation owing to their lower cost and fuel economy advantages. In the present work, a small single cylinder diesel engine is initially operated under conventional combustion mode at rated speed, varying load conditions to establish the base line reference data. Then, the engine is modified to operate under RCCI combustion mode with a newly designed cylinder head to accommodate a high pressure, fully flexible electronically controlled direct diesel fuel injection system, a low pressure gasoline port fuel injection system and an intake air pre heater. Using a National Instruments (NI) controller, the engine operating parameters in terms of direct injected diesel fuel timings, injection pressures, port injected gasoline fuel timings, intake air temperatures and gasoline to diesel fuel ratio at each load conditions are optimized to achieve maximum brake thermal efficiency. The obtained results show that the engine could be operated under RCCI combustion mode over its complete load range at rated speed with a 14.7% higher brake thermal efficiency, near zero NOx and smoke emissions along with a lower rate of pressure rise as compared to conventional combustion. Thus, the present work demonstrates that RCCI is feasible to achieve and has a greater potential to significantly improve fuel economy along with achieving near zero NOx and smoke emissions in small single cylinder diesel engines.
M, Murugesa Pandian, Krishnasamy, Anand
An Investigation Into the Port Timing of a Burt-McCollum Sleeve Valve and Its Interaction with a Simple Variable Compression Ratio Mechanism2017-24-01689/4/2017
Modern automotive engines almost exclusively operate on the 4-stroke Otto cycle and utilize poppet valves for gas exchange. This state of affairs has not always been the case, however, and one unusual and relatively successful technology that was once in mass production (albeit in piston aero engines) was the Burt-McCollum single sleeve valve. This paper investigates the timing and angle-area of a Bristol Centaurus engine cylinder, which utilized such a single sleeve valve for gas exchange, using some modern tools. A comparison with poppet valve angle-areas is made. Finally, the results are also used to study the potential of variable valve timing and the interaction with variable compression ratio of a single sleeve mechanism. An opportunity for the sleeve valve is provided by the fact that direct injector placement in the cylinder junk head is effectively completely free, and furthermore multiple ignition sites can be incorporated to increase the delivered ignition energy for dilute mixtures, for example. Furthermore, as there are no mechanical impact loads (as arise from poppet valves hitting their seats, for instance), theoretically ceramics or temperature-swing materials could be more simply applied when using the technology as well, and over a larger proportion of the total combustion chamber surface area than is possible with poppet valves. The motivation for studying the interaction of timing and compression ratio was driven by the observation that it would be relatively simple to incorporate a wide-range continuously-variable compression ratio mechanism without the spatial limitations enforced by the presence of poppet valves and their timing and drive mechanisms in the cylinder head of a conventional 4-stroke engine. The potential range of compression ratio variation is also significantly larger than for poppet-valve engines because the piston does not have to incorporate valve pockets for valve-to-piston clearance at high compression ratio settings. As a result the surface-area-to-volume ratio of the combustion chamber would be expected to be less effected over any given ratio range as well. The results of this study show a very favourable trade-off between port timing, compression and expansion ratios with a simple variable compression ratio mechanism being employed. Furthermore, the system is found to provide a large potential to yield increased Miller cycle operation automatically.
Turner, James W.G., Monsma, James P. Lewis
Low Volatility Fuel Cold Start Experience with a Stepped Piston UAV Engine to Address Single Fuel Objectives2017-01-92838/1/2017
This paper reports on the research and development challenges experienced from dynamometer testing of a spark ignition UAV engine operating on heavy fuel. The engine is a segregated scavenging two stroke engine with air charge delivery by means of integral stepped pistons overcoming durability issues of conventional crankcase scavenged engines. A key element of the experimental study builds upon performance development to address the need for repeatable cold start on low volatility fuel thereby eliminating gasoline from UAV theatres of deployment. Lubrication challenges normally associated with crankcase scavenged two stroke engines are avoided by the integrated re-circulatory lubrication system. The fuel explored in this study is kerosene JET A-1.
Hooper, Peter R.
Structure Borne Noise Optimization of Diesel Engine by Simulation2017-28-19447/10/2017
The vibration and acoustic behaviour of the internal combustion engine is a highly complex one, consisting of many components that are subject to loads that vary greatly in magnitude and which operate at a wide range of speeds. The interaction of these components and the excitation of resonant modes of vibration is a major problem for the powertrain engineer when optimising the noise and vibration characteristics of the engine. This paper summarises a study that has been undertaken to assess and optimise the dynamic behaviour of a current production diesel engine with the objective of reducing radiated noise from the engine. The dynamic behaviour of the diesel engine has been assessed using simulation tools. The dynamic analysis will predict the forces and displacements at each of the nodes of the model by forced response analysis. Predicted results and experimentally measured values were found to be in close agreement. A number of production feasible design modifications have been considered and analysed. Structural modifications viz. ribbing pattern, stiffeners and gusset additions were suggested by taking reference of NSI findings to improve the overall stiffness of the engine assembly. It has been demonstrated that by changing material such as visco elastic material gives reductions in radiated noise. The hybrid approach so used helped in reducing noise level of engine to meet set noise level targets with a minimal increase in overall mass.
Shaik Mohammad, Asif Basha, Vijayakumar, Ravindran, Panduranga, Nageshwara Rao
Lubricants for Two-Stroke-Cycle Gasoline EnginesJ1510_201705 (Current)5/25/2017
The information in this SAE Recommended Practice has been compiled by Technical Committee 1 (Engine Lubrication) of the SAE Fuels and Lubricants Division. The intent is to provide those concerned with the design and maintenance of two-stroke-cycle engines with a better understanding of the properties of two-stroke-cycle lubricants. Reference is also made to test procedures which may be used to measure the chemical and physical characteristics of these lubricants.
Fuels and Lubricants TC 1 Engine Lubrication
A Thermal Bus for Vehicle Cooling Applications - Design and Analysis2017-01-02663/28/2017
Designing an efficient cooling system with low power consumption is of high interest in the automotive engineering community. Heat generated due to the propulsion system and the on-board electronics in ground vehicles must be dissipated to avoid exceeding component temperature limits. In addition, proper thermal management will offer improved system durability and efficiency while providing a flexible, modular, and reduced weight structure. Traditional cooling systems are effective but they typically require high energy consumption which provides motivation for a paradigm shift. This study will examine the integration of passive heat rejection pathways in ground vehicle cooling systems using a “thermal bus”. Potential solutions include heat pipes and composite fibers with high thermal properties and light weight properties to move heat from the source to ambient surroundings. An initial case study focuses on the integration of heat pipes in a thermal bus to transfer heat from the thermal load (e.g., internal combustion engine, electric motor, battery pack, power electronic, etc.) to the heat exchanger. A mathematical U-shaped pulsating heat pipe model is used to numerically describe the thermal behavior of a heat pipe based thermal bus. This is combined with models for a “cradle” to move energy from the load to the bus and a model for a heat exchanger to ambient. Simulation results indicate that the heat dissipation rate is significantly influenced by heat pipe length, diameter and the temperature difference between the heat load and the bus. The integration of this heat pipe based thermal bus within an active / passive cooling system will be demonstrated in future work.
Rizzo, Denise, Shurin, Scott, Shoai Naini, Shervin, Huang, Junkui (Allen), Miller, Richard, Wagner, John R., Sebeck, Katherine
Literature Survey of Water Injection Benefits on Boosted Spark Ignited Engines2017-01-06583/28/2017
The automotive industry has been witnessing a major shift towards downsized boosted direct injection engines due to diminishing petroleum reserves and increasingly stringent emission targets. Boosted engines operate at a high mean effective pressure (MEP), resulting in higher in-cylinder pressures and temperatures, effectively leading to increased possibility of abnormal combustion events like knock and pre-ignition. Therefore, the compression ratio and boost pressure in modern engines are restricted, which in-turn limits the engine efficiency and power. To mitigate conditions where the engine is prone to knocking, the engine control system uses spark retard and/or mixture enrichment, which decrease indicated work and increase specific fuel consumption. Several researchers have advocated water injection as an approach to replace or supplement existing knock mitigation techniques. Water, having high latent heat of vaporization, acts as a heat sink and reduces temperatures in the end gas zone, thereby reducing the tendency for auto-ignition. The added water also changes the ratio of specific heats of the charge mixture, and slightly dilutes the oxygen concentration. These changes greatly reduce the tendency to knock or detonate, in addition to reducing NOx emissions. The optimum strategy for injection to maximize benefits is still debatable, due to the fact that the latent heat of vaporization decreases as pressure increases. The ability of water to improve anti-knocking properties can potentially allow engine designs with higher compression ratio and boost pressure, and this will enable operation closer to maximum brake torque (MBT) spark timing under all operating conditions. It is worth to note that most of the research work done on water injection focuses on extending permissible engine power output. However the current trend toward boosted and downsized engines demands extending the knock limit without increasing exhaust temperatures or specific fuel consumption (which are the major limitations of existing knock mitigating techniques). This paper examines the prior research in using water injection to extend knock limit in boosted spark ignition engines, and its potential effects on performance and emissions.
Rohit, Achint, Satpathy, Sridev, Choi, Jeongyong, Hoard, John, Surnilla, Gopichandra, Hakeem, Mohannad
Experimental Study on Optimization of the Intake Ports for Improving the Thermal Efficiency of Small Engines for Motorcycles2016-32-007911/8/2016
With the remarkable rise of gas prices and global air pollution, measures to improve fuel efficiency and reduce emissions have become urgently needed in the motorcycle industry, as in the automobile industry. One approach is to improve the thermal efficiency of the engine, and much research and development has been done for many years on this subject. Community-based small motorcycles require both high mobility and fuel efficiency in developed and developing countries. Drivability and emission control of recreation and sports motorcycles are also needed. However, when developing engines for small motorcycles, due to differences in engine speed range, driving load range, devices for driving and emission control, market prices, and infrastructure, some different approaches from those for automobile engines with their many advanced technologies are needed. This report describes mainly techniques for optimizing the shapes of the intake port and its outskirts based on a wealth of knowledge about improving thermal efficiency gained during engine development. Using the results of both combustion analysis and the flow state at a dynamo bench and a flow bench with an actual engine, and forecasts of the internal flow by three-dimensional steady and non-steady flow analysis were adapted to develop the specifications. As a result, the combustion between cycles was stabilized with less fuel by intensifying the turbulence energy around the spark plug, ideally being controlled the fresh air-fuel mixture before ignition and increasing atomization of the fuel. Moreover, ISFC was able to be improved from our previous engines without sacrificing drivability.
Fukui, Daisuke, Ninomiya, Yoshinari
Effect of Air-Fuel Ratio and Operating Conditions on Particle Emissions from a Small Diesel Engine2016-32-006911/8/2016
Non-volatile particle number distributions from a single cylinder industrial diesel engine were measured at several operating conditions spanning the torque curve. The effect of increasing the air-fuel ratio by injecting compressed shop air at various boost pressures was also investigated. A bi-modal distribution separated at approximately 20 nm was observed for most operating conditions. Depending on operating condition, the engine produced between 1014 to 1015 particles per kW-hr. Energy specific particle number emissions (per kW-hr) were seen to be strongly dependent on speed and load. Minimum emissions occurred at intermediate speeds and loads. Particles below 20 nm increased with decreasing load while the opposite trend was observed for particles greater than 20 nm. Variation in total particle surface and total particle volume followed the same trends as the particles from the larger mode. The most interesting result was that external air-injection at the engine intake had almost no beneficial effect on energy specific particle number emissions, although it increased the air-fuel ratio substantially with numbers ranging from 50 to 200. The increase of particle numbers with decreasing load for sub-20 nm particles continued with external air-injection. These findings are interesting given the ubiquity of small diesels for portable/backup power, industrial and agricultural uses. The study suggests that significant PN emission reduction in these engines might require DPFs.
Brahma, Indranil, Manzanares, Cristobal, Jennings, Rob, Ofili, Odinmma, Campbell, Matthew, Raghavan, Abishek, Johnson, Daniel, Stryker, Peter
Investigations and Analysis of Working Processes of Two-Stroke Engines with the Focus on Wall Heat Flux2016-32-002811/8/2016
Small displacement two-stroke engines are widely used as affordable and low-maintenance propulsion systems for motorcycles, scooters, hand-held power tools and others. In recent years, considerable progress regarding emission reduction has been reached. Nevertheless, a further improvement of two-stroke engines is necessary to cover protection of health and environment. In addition, the shortage of fossil fuel resources and the anthropogenic climate change call for a sensual use of natural resources and therefore, the fuel consumption and engine efficiency needs to be improved. With the application of suitable analyses methods it is possible to find improving potential of the working processes of these engines. The thermodynamic loss analysis is a frequently applied method to examine the working process and is universally adaptable. Within this paper, a series production small displacement two-stroke engine is experimentally investigated on the test bench and adapted with measuring equipment in order to analyze the working process with focus on the wall heat flux. Due to high speed and vibrations, these investigations are complex. This publication considers an assessment of correlation predictability of heat transfer models, which are used in the thermodynamic loss analysis, by means of a comparison with experimental data. Thereto the measurement technique based on the surface temperature method applied to a small two-stroke engine is explained. From these investigations, the thermodynamic loss analysis regarding wall heat loss is reassessed and improvement potential is pointed out. Finally, an alignment of the thermodynamic loss analysis for small displacement two-stroke engines regarding the wall heat losses is performed. The results of the thermodynamic loss analysis demonstrate the occurring efficiency losses and therewith improvement strategies concerning the working process can be deduced.
Piecha, Pascal, Bruckner, Philipp, Schmidt, Stephan, Kirchberger, Roland, Schumann, Florian, Meyer, Stephan, Gegg, Tim, Leiber, Stefan
Effect of Variable Cooling System for Fuel Economy Improvement on Scooter with Air Cooled Engine2016-32-009211/8/2016
A variable cooling system has been developed for scooters equipped with an air cooled, four-stroke, single cylinder gasoline engine. This system opens or closes louver located at the cooling air inlet using an oil-temperature sensitive actuator. When the engine is cold or the engine load is low, the louver shut off the cooling air for a quick warm-up and for maintaining the engine oil temperature high to reduce the friction losses that occur with low oil temperature while eliminating the loss from driving the cooling fan as well. The quick warm-up also decreases supplementary fuel injections necessary when the engine is cold. Consequently, fuel economy improvement by 3.3% was realized in running condition of the Urban Driving Cycle.
Kobayashi, Tomokazu, Kosei, Kazuyuki, Ito, Sadaaki, Iijima, Satoshi
Applying Combustion Chamber Surface Temperature to Combustion Control of Motorcycle Engines2016-32-008711/8/2016
Motorcycle usage continues to expand globally. Motorcycles use various fuels in different countries and regions, and it is required that they comply with emissions and fuel consumption regulations as specified in UN-GTR No.2 (WMTC). In general, a motorcycle engine has a large bore diameter and a high compression ratio due to demands of high performance. Poor fuel quality may cause damage to the engine, mainly by knocking. Knock control systems utilizing high-frequency vibration detection strategies like knock sensors, which are equipped on several sport-touring motorcycles, are not used widely for reasons of complex construction and high cost. This research aims to develop a new concept of combustion control for common motorcycle as an alternative. The new combustion control focuses on the effect of engine combustion-chamber surface temperature, because a proportional relationship exists between the combustion chamber surface temperature and the pressure peak within the cylinder, and the combustion chamber temperature shows a sharp increase when knocking occurs. The difference between the combustion chamber surface temperature and the engine reference temperature was used as an indicator of the combustion state, and it was compared with that of an ideal state calculated from the generated torque. The ignition timing is adjusted so that, if the actual temperature is lower than the ideal temperature, the cylinder internal pressure is increased in order to raise the temperature, and if the actual temperature is higher than the ideal temperature, the cylinder internal pressure is reduced in order to lower the temperature. When we applied this control algorithm to actual motorcycles, we obtained results showing its effectiveness in preventing engine damage from knocking and improving transient torque in the transition of acceleration from low-load to high-load.
Ichihashi, Satoshi
High Performance Aluminum Casting Alloys for Engine Applications2016-32-001911/8/2016
In the early 1980's, some promising research and development efforts focused on powder metallurgy revealed that aluminum alloys containing 4 wt% cerium exhibit high temperature mechanical properties exceeding those of the best commercial aluminum casting alloys currently in production. Cerium oxide is an abundant rare earth oxide that is often discarded during the refining of more valuable rare earths such as Nd and Dy. Therefore, the economics are compelling for cerium as an alloy additive. In this paper, we report select results obtained during an investigation of the castability of aluminum-cerium alloys and determine compositional modifications that may be required to ensure the compatibility of the alloy with near net shape casting methods such as advanced sand casting, die casting, permanent mold casting and squeeze casting. Al-Ce alloys were cast in binary composition of 6-16 wt% Ce. Commercially pure aluminum ingots were melted and held at approximately 785°C. Ternary and quaternary alloys with Si and Mg additions were also investigated. Test bars were cast to establish mechanical properties and step plates and hot tear molds were used to determine sensitivity to solidification conditions and hot tearing sensitivity respectively. Finally, air cooled engine cylinder heads were cast in sand molds to get a sense of castability in complicated shape castings.
Weiss, David
The Effect of Lean Operation, Ignition Advance, and Compression Ratio on the Performance and Emissions of a Propane Fueled Electronic Fuel Injected Engine2016-32-006811/8/2016
The performance and exhaust emissions of a commercially available, propane fueled, air cooled engine with Electronic Fuel Injection (EFI) were investigated by varying relative Air to Fuel Ratio (λ), ignition timing, and Compression Ratio (CR). Varying λ and ignition timing was accomplished by modifying the EFI system using TechniCAL Industries’ engine development software. The CR was varied through using pistons with different bowl sizes. Strong relationships were recorded between λ and ignition timing and the resulting effect these parameters have on engine performance and emissions. Lean operation (λ > 1) has the potential to significantly reduce NOx production (110 g/kW-hr down to 5 g/kW-hr). Unfortunately, it also reduces engine torque by up to an order of magnitude (31 Nm down to 3 Nm). Moving ignition initiation to earlier in the compression stroke, 10o to 40o Before Top Dead Center (BTDC), improved engine performance considerably (25% improvement in brake torque) in the presence of excess air. Unfortunately, advancing the ignition also caused NOx production to increase. The effects these parameters have on engine performance are significant enough that the same engine can be used for vastly different applications with changes only to the control software. Compression ratio has a less significant effect on engine performance, but increasing CR does result in an increase engine torque. Increasing CR from 9.1:1 to 11:1 resulted in an increase in engine torque of approximately 10% for the operating parameters tested.
Lobo, Joel Prince, Lee, James Howard, Oswald, Eric, Lionetti, Spenser, Garrick, Robert
Computational Development of a Dual Pre-Chamber Engine Concept for Lean Burn Combustion2016-01-224210/17/2016
Pre-chambers are a means to enable lean burn combustion strategies which can increase the thermal efficiency of gasoline spark ignition internal combustion engines. A new engine concept is evaluated in this work using computational simulations of non-reacting flow. The objective of the computational study was to evaluate the feasibility of several engine design configurations combined with fuel injection strategies to create local fuel/air mixtures in the pre-chambers above the ignition and flammability limits, while maintaining lean conditions in the main combustion chamber. The current work used computational fluid dynamics to develop a novel combustion chamber geometry where the flow was evaluated through a series of six design iterations to create ignitable mixtures (based on fuel-to-air equivalence ratio, ϕ) using fuel injection profiles and flow control via the piston, cylinder head, and pre-chamber geometry. The desirable and undesirable features that guided the design progression are presented. Major combustion chamber design iterations involved changes to the pre-chambers position relative to the cylinder head deck plane, azimuthal orientation of the pre-chambers, and piston crown geometry. Further criteria were developed to assess the flow interaction with the nozzle connections to the pre-chambers. The modeling results indicated appropriate fueling strategies achieved near stoichiometric fuel-to-air equivalence ratios in the pre-chambers with lean fuel-to-air equivalence ratios in the main chamber. The results also demonstrated the utility of the flow-alignment and chamber filling criteria to select the nozzle design for the pre-chambers.
Assanis, Dimitris, Engineer, Nayan, Neuman, Paul, Wooldridge, Margaret
Small Craft - Marine Propulsion Engine and Systems - Power Measurements and DeclarationsJ1228_201604 (Current)4/6/2016
This SAE Standard specifies the test requirements in addition to those given in ISO 3046-1 for determining the power, at a single point or as a power curve, of marine propulsion engines or systems for recreational craft and other small craft using similar propulsion equipment of less than 24 m length of the hull. It also provides the means for documenting and checking the declared (rated) power published by the manufacturer.
Marine Technical Steering Committee
Automotive Direct-Injection Stratified-Charge Engine Development in the 1970-1980’s2016-01-01754/5/2016
Spark-ignition direct-injection technology existed since about 1930 for the primary purpose to give multifuel capability over what the compression-ignited diesel engine could provide. In subsequent decades development of multifuel engines continued both as higher-compression-ratio “spark-ignited diesel” and moderate-compressionratio stratified-charge engines. Global events in the 1960-1970’s, namely the oil embargo, oil-supply crises, and the passage of the U.S. Clean Air Act intensified interest in such engines. The military and large commercial fleet operators were particularly focused on efficiency and multifuel capability over concerns for fuel supplies. Automobile manufacturers were focused on gasoline-fueled efficiency and the potential to reduce engine-out legislated NOx emissions with the stratified-charged combustion systems. In this paper the major direct-injection spark-ignited stratified-charge concepts pursued during the 1970-1980’s are reviewed at a high level, and relevant references are cited. Examination of this development history should be of interest to those working on modern gasoline direct-injected engines, as a variety of concepts were pursued, with the physics of those combustion processes being pertinent to today’s systems in production and under development. In many cases advances in fuel-injection hardware, enabled by modern manufacturing methods, and control technologies, enabled by modern computers and sensors, have allowed design objectives of the past to be implemented successfully today.
Groff, Edward G.
Unique Needs of Motorcycle and Scooter Lubricants and Proposed Solutions for More Effective Performance Evaluation2015-32-070811/17/2015
The operating conditions of a typical motorcycle are considerably different than those of a typical passenger car and thus require an oil capable of handling the unique demands. One primary difference, wet clutch lubrication, is already addressed by the current JASO four-stroke motorcycle engine oil specification (JASO T 903:2011). Another challenge for the oil is gear box lubrication, which may be addressed in part with the addition of a gear protection test in a future revision to the JASO specification. A third major difference between a motorcycle oil and passenger car oil is the more severe conditions an oil is subjected to within a motorcycle engine, due to higher temperatures, engine speeds and power densities. Scooters, utilizing a transmission not lubricated by the crankcase oil, also place higher demands on an engine oil, once again due to higher temperatures, engine speeds and power densities. However, because scooter oils do not need to lubricate a wet clutch or protect gears, scooter oils can provide more fuel economy benefits than motorcycle oils, when properly formulated. First, this study compares the piston deposit performance of motorcycle oils and passenger car oils in the API Sequence III Test and in a fired-engine motorcycle piston deposit evaluation. While the API Sequence III Test is certainly an effective tool for ensuring passenger car motor oil piston deposit performance, the results show that some oils formulated to meet the performance requirements of the Sequence III test do not match the performance of motorcycle-specific oils in a motorcycle piston deposit evaluation. Second, this study compares the performance of different oils in the JASO clutch friction test (SAE#2) and in a fired-engine Scooter Fuel Economy Test. The results indicate that JASO MB performance, as determined by the SAE#2 clutch friction test, is not necessarily a predictor of real fuel economy benefit.
Marcella, Mike, Michlberger, Alex
Thermodynamic Limits of Efficiency Enhancement of Small Displacement Single-Cylinder Engines2015-32-081711/17/2015
Millions of small displacement single-cylinder engines are used for the propulsion of scooters, motorcycles, small boats and others. These SI-engines represent the basis of an affordable mobility in many countries, but at the same time their efficiency is quite low. Today, the limited fossil fuel resources and the anthropogenic climate require a sustainable development of combustion engines, the reduction of fuel consumption being an important factor. A variety of different strategies (turbo-charging, cylinder deactivation, direct injection, etc.) are investigated here to increase the efficiency of multi-cylinder engines. In the case of small displacement single-cylinder engines, other strategies are required because of their special design and the high pressure on costs. In the context of this paper different layout parameters which have an influence on the working process are investigated, with the aim of increasing the efficiency of small displacement single-cylinder engines. This includes parameters such as compression ratio, lambda, external EGR and others. The thermodynamic losses from ideal engine efficiency to effective efficiency are presented and the calculations are supported by experimental data. Both two-stroke and four-stroke engines are investigated and the subject is limited to single-cylinder engines with a displacement of up to 150 cm3. Furthermore, achievable efficiencies by means of air-cooling and water-cooling are presented. The focus is put on representative operation points at PL (part load) and WOT of typical motorcycle applications in Asia. The calculations are mainly of theoretical importance, but the possibilities of transferring the outcome into real applications are also discussed. Finally, the paper concludes with an evaluation of appropriate strategies to reduce fuel consumption.
Trattner, Alexander, Kupelwieser, Florian, Pertl, Patrick, Winkler, Franz, Schmidt, Stephan, Kirchberger, Roland
Investigation of In-Cylinder Heat Flux in a Single Cylinder, 4 Stroke, Air Cooled, Spark Ignition Engine for Motorcycle Application2015-32-080411/17/2015
Heat flux measurements can provide much needed insight into the energy flow inside an IC engine, which is the key to optimizing its performance. This paper focuses on understanding the nature of heat flux curve and how it varies with varying load conditions, engine speed, Air fuel ratio and ignition timing in a single cylinder, 4 stroke, carbureted, air cooled, spark ignition engine for motorcycle application. In-cylinder heat flux was monitored along with wall temperature and cylinder pressure for motored operation as well as fired conditions. The difference between the motoring mode and fired mode was analyzed to separate out the effects of combustion. In general, the magnitude of maximum heat flux was found to increase with engine rpm and load when all other engine parameters remained constant. The heat flux was found to increase when a mixture setting closer to the stoichiometric value was used. While studying the effect of ignition timing, it was observed that the peak cylinder pressure and cylinder head wall temperatures increased as the ignition timing was advanced. However, there exists a particular value of ignition timing for which the heat flux peaked for any set of operating conditions and advancing the timing any further resulted in a decrease in the magnitude of peak heat flux regardless of the fact that the cylinder pressure continued to rise well beyond this point.
Rajagopalan, V.R, Anand, S, Nagendra Kumar, D, Karunaharan, V, Lakshminarasimhan, V
Effect of Compression Ratio on the Performance Characteristics of Spark Ignition Engine Fueled with Alternative Fuels: A Review2015-01-07664/14/2015
This paper reviews the works done on ‘influence of compression ratio (CR) on the performance of spark ignition(SI) engine using fuel blends of ethanol namely E0 (gasoline), E25 (75% gasoline, 25% ethanol), E10, E20, E22, E50, E75, E100 for different CR. The main parameters considered for comparison were brake specific fuel consumption (BSFC), CR, brake torque (BT), air-fuel ratio (AFR) and exhaust emissions. The experimental results of various studies are compared. The need of advanced engine development techniques and modifications are also studied and emphasis is laid on the use of variable compression ratio (VCR) SI engine. The benefits of using VCR in the coming future are discussed briefly mentioning the challenges faced. It is concluded that gasoline-ethanol fuel blends increase the overall output of engine whilst reducing the harmful emissions and increasing engine reliability and life, at higher compression ratios and thus providing a new platform in the automobile sector for its further development.
Goswami, Anshuman, Vashist, Sagar, Nayyar, Ashish
Impact of Swirl Ratio on Combustion Performance of a Non-Pent Roof Combustion Chamber Engine2015-01-07434/14/2015
In response to the sensitivity to diesel aftertreatment costs in the medium duty market, a John Deere 4045 was converted to burn gasoline with high levels of EGR. This presented some unique challenges not seen in light duty gasoline engines as the flat head and diesel adapted ports do not provide optimum in-cylinder turbulence. As the bore size increases, there is more opportunity for knock or incomplete combustion to occur. Also, the high dilution used to reduce knock slows the burn rates. In order to speed up the burn rates, various levels of swirl were investigated. A four valve head with different levels of port masking showed that increasing the swirl ratio decreased the combustion duration, but ultimately ran into high pumping work required to generate the desired swirl. A two valve head was used to overcome the breathing issue seen in the four valve head with port masking. The low swirl port design in the two valve head offered a similar swirl ratio while the high swirl port design offered a swirl ratio double that of the low swirl port. The results from the experiments illustrate a trade-off between swirl ratio and heat transfer. While the highest swirl port slightly improved EGR tolerance and burn rates, it had a significant increase in heat transfer and pumping work causing a overall decrease in efficiency. An optimal swirl ratio exists such that the pumping and heat transfer losses are overcome by the improvement in burn rates and EGR tolerance.
Kocsis, Michael Clifford, Joo, Shinhyuk, Briggs, Thomas, Alger, Terrence
Online Engine Speed based Altitude Adaptation of Air Charge and Limp Home for Two-Wheelers2014-32-006711/11/2014
Cost reduction of engine management systems (EMS) for two-wheeler applications is the key to utilize their potentials compared to carburetor bikes regarding emissions, fuel economy and system robustness. In order to reduce the costs of a system with port fuel injection (PFI) Bosch is developing an EMS without a manifold air pressure (MAP) sensor. The pressure sensor is usually used to compensate for different influences on the air mass, which cannot be detected via the throttle position sensor (TPS) and mean engine speed. Such influences are different leakage rates of the throttle body and changing ambient conditions like air pressure. Bosch has shown in the past that a virtual sensor relying on model based evaluation of engine speed can be used for a detection of leakage air mass in idling to improve the pre-control of the air-fuel ratio. This provides a functionality which so far was only possible with an intake pressure sensor. In this paper the air mass calculated from the model based engine speed evaluation is used to adapt the influence of ambient pressure changes e.g. because of different altitudes. Furthermore, the usability of the engine speed based air mass for the realization of a limp home mode in case of a malfunction of the throttle position sensor is evaluated. Therefore, a demonstrator bike is equipped with an additional switch to bring in certain TPS errors which will be detected by the EMS.
Heikes, Henning, Steinbrecher, Christian, Reineke, Bastian, Berkemer, Jürgen, Raatz, Thorsten, Fischer, Wolfgang
CFD Analysis of a Two-Stroke Air Cooled Engine Designed for Handheld Products2014-32-000611/11/2014
Still today, two-stroke engine layout is characterized by a wide share on the market thanks to its simpler construction that allows to reduce production and maintenance costs respecting the four-stroke engine. Two of the main application areas for the two-stroke engines are on small motorbikes and on handheld machines like chainsaws, brush cutters, and blowers. In both these application areas, two-stroke engines are generally equipped by a carburettor to provide the air/fuel mixture formation while the engine cooling is assured by forcing an air stream all around the engine head and cylinder surfaces. Focusing the attention on the two-stroke air-cooling system, it is not easy to assure its effectiveness all around the cylinder surface because the air flow easily separates from the cylinder walls producing local hot-spots on the cylinder itself. This problem can be bounded only by the optimization of the cylinder fin design placed externally to the cylinder surface. In the present paper the authors present a first analysis of the thermal-flow behaviour of a two stroke engine designed for brush-cutter machine applications. The optimization of the air-cooling system of such a machine is a very challenging task because the machine design is very compact forcing all the engine parts to remain quite close to each other. The proposed analysis is performed by the definition of a specific 3D-CFD simulation methodology based on the Conjugated Heat Transfer approach. The methodology was validated against experimental data.
Brusiani, Federico, Bianchi, Gian Marco, Catellani, Cristian, Ferrari, Marco, Verziagi, Paolo, Catanese, Dario
Air Cooled 50cm 3 Scooter Euro 4 Application of the Two-Stroke LPDI Technology2014-32-000811/11/2014
The Institute for Internal Combustion Engines and Thermodynamics, Graz University of Technology, has presented several applications of its 2-stroke LPDI (low pressure direct injection) technology in the previous years ([1], [2], [3]). In order to improve the competitiveness of the 2-stroke LPDI technology, an air cooled 50cm3 scooter application has been developed. All previous applications have been liquid cooled. This air cooled application demonstrates the EURO 4 (2017) ability of the technology and shows that the 2S-LPDI technology can also be applied to low cost air-cooled engines. Hence, the complete scooter and moped fleet can be equipped with this technology in order to fulfil both the emission standards and the COP (conformity of production) requirements of Euro 4 emission stage. The paper presents the Euro 4 Scooter results and describes the efficient conversion process of the existing carburetor engine to the LPDI version. Euro 4 results can be achieved with conventional exhaust system architecture known from the present Euro 2 applications. Costs can be even reduced by omitting the secondary air system and choosing a cheaper catalyst - 100 cpsi instead of 200 cpsi. Therewith the costs for the basic engine (hardware) are on the same level as or even lower than for actual Euro 2 engines. A special engine development is NOT required, which leads to a simple modification of existing models. To be able to apply the LPDI technology to air cooled engines, a special heat protection for the fuel injector, located in the cylinder, has been developed. This solution allows stabilizing the temperature of the fuel injector tip below 100°C and therefore it lies below the component limit of 125°C.
Krimplstätter, Stefan, Winkler, Franz, Oswald, Roland, Kirchberger, Roland
Detecting a Fully-Closed Throttle by Manifold Pressure in Fuel Injection System with Idle Speed Control2014-32-007511/11/2014
Various sensors including throttle position sensors (TPS), manifold pressure sensors (MPS), crank angle sensors, engine temperature sensors, and oxygen sensors are mounted in electronically controlled fuel injection (FI) systems to accurately regulate the air-fuel ratio according to the operating state and operating environment. Among these vehicle-mounted sensors, TPS has functions for detecting a fully-closed throttle and estimating intake air volume by the amount of throttle opening. Currently, we have conducted a study on transferring TPS functions into the MPS (manifold pressure sensor) in order to eliminate the TPS. Here we report on detecting a fully-closed throttle for achieving fuel cut control (FCC) and idle speed control (ISC) in fuel injection systems. We contrived a means for fully-closed throttle detection during ISC and controlling changes in the bypass opening during FCC in order to accurately judge each fully-closed throttle state via the manifold pressure. A factor in causing fluctuations in manifold pressure in a fully-closed throttle state are changes in the engine RPM (also referred to as engine speed) and changes in the degree of opening of the bypass (hereafter simply bypass opening). By keeping the bypass opening during FCC we limited the cause of fluctuations in manifold pressure to just the engine RPM; and by comparing the manifold pressure with an manifold pressure threshold equivalent to a fully-closed throttle detected at each engine RPM, we were able to accurately detect fully-closed throttle states. Another achievement was detecting a fully-closed throttle state during idling for performing ISC. This ISC adjusts the bypass opening in order to converge the engine RPM during idling to the target RPM. In other words, the manifold pressure during idling fluctuates due to two causes or namely the engine RPM and the bypass opening. So by comparing the manifold pressure with a manifold pressure threshold value equivalent to a fully-closed throttle state from the bypass opening and engine RPM we succeeded in contriving a method to detect a fully-closed throttle state with good accuracy. We found that this control technology accurately achieves fully-closed throttle detection by manifold pressure which is one of the TPS functions.
Shimatani, Kazuyoshi
Air Fuel Ratio Control for V2 Engine with On-Line System Identification of Fuel Film Dynamics2014-32-007811/11/2014
Fuel film dynamics in the intake manifold are considered to develop air fuel ratio (AFR) control strategy with on-line system identification for a V2 engine in this paper. A1000 cc four-stroke two-cylinder, water-cooled port injection SI engine is used as the target engine to develop the engine model in Matlab/Simulink. The model which consists of charging, fueling, combustion, friction, and engine rotational dynamics is used to verify the proposed AFR control. Since the fuel film dynamics changes with different engine operating conditions, the fuel film parameters are often listed as look-up tables for fuel film dynamics calculation in the conventional AFR control. However, those parameters might be inaccurate during transient engine operation. Different intake port temperature will affect the accuracy of those fuel film parameters as well. In order to solve this problem, recursive least square (RLS) is used to identify those parameters on-line. Kalman filter is utilized to estimate the AFR using a narrow-band oxygen sensor. Model predictive control is used to design the proposed AFR controller using the identified parameters of fuel film dynamics and estimated AFR. Simulation results show that those parameters identified using RLS are more accurate to describe the transient fuel film dynamics than that from look-up tables. In addition, using the proposed AFR control strategy, AFR can be controlled at the desired value both in steady state and transient engine operation.
Chen, Bo-Chiuan, Wu, Yuh-Yih, Tsai, Wen-Han, Tsai, Hsien-Chi, Lin, Huang-Min, Liang, Yao-Chung
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