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Journal Article

An Improved Physics-Based Combustion Modeling Approach for Control of Direct Injection Diesel Engines

2020-07-01
Abstract Cycle-by-cycle combustion prediction in real time during engine operation can serve as a vital input for operating at optimal performance conditions and for emission control. In this work, a real-time capable physics-based combustion model has been proposed for the prediction of the heat release rate in a direct injection diesel engine. The model extends the approaches proposed earlier in the literature by considering spray dynamics such as spray penetration and Sauter mean diameter in order to calculate the mass of evaporated fuel from the spray. Wall impingement of the liquid spray is predicted by considering the liquid length based on the prevailing in-cylinder conditions. These effects are considered even after the hydraulic end of injection till the last droplet of fuel impinges on the combustion chamber wall. The fuel evaporated from the wall film and its contribution to the kinetic energy of the charge are also considered.
Technical Paper

Benefits of Electronic Assisted Variable Geometry Turbocharging on Sports Utility Vehicle

2020-09-25
2020-28-0328
Turbocharging of diesel engines have undergone various phases of technological advancements proving merits with engine performance. Since VGTs are finding their applications in many automotive engines, it is also crucial on finding out ways to extract maximum benefits from the system. Pneumatic actuated VGTs control the vanes positioning with the help of mechanical linkages and don’t prove good in transient response with relatively slower boost build up. The electronic controlled VGT operates with the aid of DC motor which is linked to the engine management system. The position sensor senses the current position of the actuator which is controlled by the engine management system for delivering the desired boost pressure. The eVGT system thus provides very quick response and accurate control of boost pressure in all the vehicle driving conditions.
Technical Paper

EGR Mixer Optimization for Achieving Uniform Cylinder EGR Distribution Using 1D-3D CFD Coupled Simulation Approach to Meet Future Stage V Emission Legislation in India

2020-09-25
2020-28-0390
Vehicles are one of the main sources of pollution in India, which produce substantial amount of pollutants. Gaseous pollutants are reason for major health problems; hence emission legislations are becoming increasingly stringent all over the world. India is also following the global trend of migrating in the Off-highway segment from Trem IIIA to Stage V legislation by 2024. This legislation change is calling for technological upgrade of all existing engines. EGR has been successfully proved as a useful technology to reduce NOx by decreasing the oxygen concentration and the peak temperature of the combustion. Due to compact design and space restriction, the distance required for the homogeneous mixing of fresh air and EGR is not enough. Therefore, the mixing of the EGR and distribution of the EGR over the cylinders may not be equal.
Technical Paper

A Study on the Characteristics of Transient Response in a Turbocharged Diesel Engine

1991-11-01
912461
This study describes the results of transient behavior for a six-cylinders four-stroke turbocharged diesel engine during the change in operating conditions of the engine by using the computer simulation with measurements on test bed. In order to obtain the dynamic behaviors of the engine, the transient simulation are conducted with serveral kinds of inertia moment ratio in turbocharger and engine, a rapid large load application to the engine, and changes of governor gain constant. From the results of this study, the following conclusions may be summarized. Turbocharger lag is the main cause of the inferior transient performances of turbochared diesel engines. A reduction in the turbocharger moment ratio of inertia brings about the improvement of acceleration performance of disel engines. An increase of the engine moment ratio of inertia decreases cyclic variations of the engine speed.
Technical Paper

A Temperature Controller for Glow Plugs and its Usage in an Engine

1991-11-01
912510
Increased power outputs in high performance diesel engines are being obtained by the use of increased boost pressures obtained from the engine's turbochargers. Reduced compression ratio because of high boost tends to cause cold starting problems and white smoke at idle and light load, especially with a cold engine. One method of alleviating these problems is to make use of glow plugs in the engine cylinders. Applications of glow plugs include a glow plug ignited natural gas engine, methanol DI engine, and IDI and DI diesel engines. This paper describes a glow plug control system that actually controls the glow plug temperature directly. This new control system is better than the systems currently fitted to IDI diesel vehicles. The glow plug controller maintains a constant temperature at the glow plug without the use of any sensor external to the glow plug.
Technical Paper

A Trap Oxidizer System for the Turbocharged Diesel Engine

1991-02-01
910137
This paper presents the experience gained by testing a trap system on a turbocharged bus engine. The trap is placed before the turbo in order to fully exploit the high regeneration potential of the turbocharged engine. This of course necessitates a new consideration of the turbocharging system, in order to keep a good turbocharger response. The quick temperature response of the light-weight exhaust manifold installed with the system, partially offsets in this respect the thermal inertia of the ceramic trap. The effects of the use of Cerium or Copper-based fuel additives enhancing regeneration capability are presented, in order to allow preliminary assessment of optimization capabilities for the final version of the system to be used with the bus. Regeneration of this system is effected through the application of exhaust throttling before the trap. The bypass technique is also applied for trap protection.
Technical Paper

Development of the Mitsubishi TF07 Model Turbocharger for 1994 U.S. and 1993 European Diesel Emission Standards

1991-02-01
910422
The exhaust emission gas regulations on truck diesel engines are becoming increasingly stringent in various countries in the coming years. The '94 EPA (U.S.A.) regulations include the entire working range of engines, including transient conditions; thus requiring a large-scale improvement in engine properties. For this reason, various engine components are now undergoing a series of improvements; in particular, the injection system has experienced a major renovation. However, the improvement of a naturally-aspirated engine has its own limit; and the turbocharged engine with inter-cooler becomes essential. Mitsubishi Heavy Industries has been pushing ahead with the development of turbochargers for use with the truck diesel engines. To assist the Diesel engine manufacture to meet these new emission regulations, we have developed various turbocharger options for improving engine performance, in addition to our continuing efforts for improving the aerodynamic properties.
Technical Paper

A Small Turbocharger for Passenger Car and Truck Applications

1991-02-01
910421
The Garrett Automotive Group of Allied-Signal, Inc. has developed a new small turbocharger to meet a worldwide demand arising from the need for fuel efficient and low emission small engines for passenger cars and light trucks. This new turbocharger, designated the GT15, is smaller, lighter and lower in cost than Garrett's successful T2 turbocharger and is also designed to meet the more stringent durability requirements of the future.
Technical Paper

Development of Abradable Flame Spray Coating Technology

1991-02-01
910400
The authors, et al. have succeeded in the practical application of the abradable flame spray coating, used in aircraft engines for the prevention of air leakage and the improvement of efficiency, to automobile turbochargers for the first time in the world. Two layers consisting of a bond coated layer and an abradable layer used to be coated by separate spray nozzles under the conventional technique. In this paper, equations of relations between various flame spray coating conditions and the quality of coated film, which were derived from measured results, will be described. Flame spray coating conditions, that allow the double layer coating by the same spray nozzle, have been determined for each layer. Temperatures and speeds of the flame were measured by means of two-color type high-speed cameras, and equations of their relations with the flame spray coating conditions are derived from the measured result.
Technical Paper

Experimental Investigation on the Effects of Cooled Low Pressure EGR and Water Injection on Combustion of a Turbocharged GDI Engine

2020-09-27
2020-24-0003
This work focuses on the effects of cooled Low Pressure EGR and Water Injection observed by conducting experimental tests consisting mainly of Spark Advance sweeps at different cooled LP-EGR and WI rates. The implications on combustion and main engine performance indexes are then analysed and modelled with a control-oriented approach, showing that combustion duration and phase and exhaust gas temperature are the main affected parameters. Results show that cooled LP-EGR and WI have similar effects, being the associated combustion speed decrease the main cause of exhaust gas temperature reduction. Experimental data is used to identify control-oriented polynomial models able to capture the effects of LP-EGR and WI on both these aspects. The limitations of LP-EGR are also explored, identifying maximum compressor volumetric flow and combustion stability as the main ones.
Journal Article

Virtual Full Engine Development: 3D-CFD Simulations of Turbocharged Engines under Transient Load Conditions

2018-04-03
2018-01-0170
The simulation of transient engine behavior has gained importance mainly due to stringent emission limits, measured under real driving conditions and the concurrently demanded vehicle performance. This is especially true for turbocharged engines, as the coupling of the combustion engine and the turbocharger forms a complex system in which the components influence each other remarkably causing, for example, the well-known turbo lag. Because of this strong interaction, during a transient load case, the components should not be analyzed separately since they mutually determine their boundary conditions. Three-dimensional computational fluid dynamics (3D-CFD) simulations of full engines in stationary operating points have become practicable several years ago and will remain a valuable tool in virtual engine development; however, the next logical step is to extend this approach into the transient domain.
Journal Article

Engine Oil Components Effects on Turbocharger Protection and the Relevance of the TEOST 33C Test for Gasoline Turbocharger Deposit Protection

2017-10-08
2017-01-2341
Countries from every region in the world have set aggressive fuel economy targets to reduce greenhouse gas emissions. To meet these requirements, automakers are using combinations of technologies throughout the vehicle drivetrain to improve efficiency. One of the most efficient types of gasoline engine technologies is the turbocharged gasoline direct injection (TGDI) engine. The market share of TGDI engines within North America and globally has been steadily increasing since 2008. TGDI engines can operate at higher temperature and under higher loads. As a result, original equipment manufacturers (OEMs) have introduced additional engine tests to regional and OEM engine oil specifications to ensure performance of TGDI engines is maintained. One such engine test, the General Motors turbocharger coking (GMTC) test (originally referred to as the GM Turbo Charger Deposit Test), evaluates the potential of engine oil to protect turbochargers from deposit build-up.
Journal Article

Divided Exhaust Period Implementation in a Light-Duty Turbocharged Dual-Fuel RCCI Engine for Improved Fuel Economy and Aftertreatment Thermal Management: A Simulation Study

2018-04-03
2018-01-0256
Although turbocharging can extend the high load limit of low temperature combustion (LTC) strategies such as reactivity controlled compression ignition (RCCI), the low exhaust enthalpy prevalent in these strategies necessitates the use of high exhaust pressures for improving turbocharger efficiency, causing high pumping losses and poor fuel economy. To mitigate these pumping losses, the divided exhaust period (DEP) concept is proposed. In this concept, the exhaust gas is directed to two separate manifolds: the blowdown manifold which is connected to the turbocharger and the scavenging manifold that bypasses the turbocharger. By separately actuating the exhaust valves using variable valve actuation, the exhaust flow is split between two manifolds, thereby reducing the overall engine backpressure and lowering pumping losses. In this paper, results from zero-dimensional and one-dimensional simulations of a multicylinder RCCI light-duty engine equipped with DEP are presented.
Journal Article

Analysis of Regulated Pollutant Emissions and Aftertreatment Efficiency in a GTDi Engine Using Different SOI Strategies

2018-06-25
Abstract In order to improve performance and minimize pollutant emissions in gasoline turbocharged direct-injection (GTDi) engines, different injection strategies and technologies are being investigated. The inclusion of exhaust gas recirculation (EGR) and the variation of the start of injection (SOI) are some of these strategies that can influence the air-to-fuel (AF) mixture formation and consequently in the combustion process and pollutant emissions. This paper presents a complete study of the engine performance, pollutant emissions and aftertreatment efficiency that produces the SOI variation with a fixed EGR rate in a 4-cylinder, turbocharged, gasoline direct-injection engine with 2.0 L displacement. The equipment used in this study are TSI-EEPS for particle measurement and HORIBA MEXA 1230-PM for soot measurement being HORIBA MEXA 7100-DEGR with a heated line selector the system employed for regulated gaseous emission measurement and aftertreatment evaluation.
Journal Article

A Method for Turbocharging Single-Cylinder, Four-Stroke Engines

2018-07-24
Abstract Turbocharging can provide a low cost means for increasing the power output and fuel economy of an internal combustion engine. Currently, turbocharging is common in multi-cylinder engines, but due to the inconsistent nature of intake air flow, it is not commonly used in single-cylinder engines. In this article, we propose a novel method for turbocharging single-cylinder, four-stroke engines. Our method adds an air capacitor-an additional volume in series with the intake manifold, between the turbocharger compressor and the engine intake-to buffer the output from the turbocharger compressor and deliver pressurized air during the intake stroke. We analyzed the theoretical feasibility of air capacitor-based turbocharging for a single-cylinder engine, focusing on fill time, optimal volume, density gain, and thermal effects due to adiabatic compression of the intake air.
Journal Article

Conditioning Turbocharger Compressor Map Data for Use in Engine Performance Simulation

2018-08-08
Abstract Turbocharger compressor maps are used in engine performance modeling and simulation to predict engine air system operating conditions. Errors in compressor map data can result in inaccurate engine performance prediction. A method is described for conditioning compressor map data for use in engine performance simulation, by detecting and replacing suspect data points, and interpolating and extrapolating the map data. The method first characterizes enthalpy rise through the compressor, after removing data points likely influenced by heat transfer from turbine to compressor, using energy transfer coefficient vs. impeller outlet flow coefficient. This is done concurrently with estimating impeller outlet conditions using simplified geometry assumptions and a modified definition for compressor stage reaction.
Journal Article

Experimental Study on the Combustion Monitoring via the Turbocharger Speed Fluctuations by Vibration Measurement

2020-10-05
Abstract To comply with the increasingly severe regulations related to exhaust emission, internal combustion engines are required to monitor their operating conditions on a continuous basis. Vibration-based techniques have been successfully applied in reciprocating engines to assess the condition of the machines and detect faults. Dealing with turbocharged engines, methodologies based on the employment of accelerometer signals to obtain an estimation of the turbocharger rotation have been proposed with the aim of using the instantaneous turbocharger speed for the engine function monitoring. The present article focuses on the analysis in time and frequency domains of the vibration signals from the compressor housing of a medium-duty, four-cylinder, turbocharged common rail diesel engine aimed at indirectly evaluating the turbocharger speed in terms of its mean component and fluctuation. Data have been acquired during experimental tests at different values of engine speed and torque.
Journal Article

Neural Network-Based Prediction of Liquid-Phase Diffusion Coefficient to Model Fuel-Oil Dilution on Engine Cylinder Walls

2020-10-02
Abstract Nowadays the role played by passenger vehicles on the greenhouse effect is of great value. To slow down both global warming and fossil fuel wasting, the design of high-efficiency engines is compulsory. Downsized Turbocharged Gasoline Direct Injection (TGDI) engines comply with both high-efficiency and power demand requirements. Nevertheless, Direct Injection (DI) inside downsized chambers may result in the fuel wall impingement, depending on the operating conditions. The impact of fuel on the cylinder liner leads to the mixing of the fuel and the lubricant oil in the cylinder wall. When the piston moves, the piston top ring scraps the non-evaporated fuel-oil mixture. Then the scraped fuel-oil mixture may be scattered into the combustion chamber, becoming a source of diffusive flames in all conditions and abnormal combustions known as Low-Speed Pre-Ignitions (LSPI) at the highest loads.
Journal Article

Machine Learning-Based Turbine Vane Position Estimation for Advanced Engine Airpath Control

2021-07-29
Abstract In an engine airpath system, modeling the nonlinearities associated with turbocharger vane position estimation is challenging as most influencing factors are not clearly known. State-of-the-art models are predominantly data driven, which makes the accuracy skewed toward the clusters with data richness. The data for these models are derived from the experiments in a dynamometer (dyno) or vehicle. The measurement data is extrapolated for the entire operating zone to derive the control models, which are inaccurate and slow in transient response. With emission norms becoming stringent, the models need to be more accurate with an improved transient response. The authors derive the synthetic data using “adaptive synthetic data generation” for the one engine operating zone. This improves the data richness of the dataset, which can be used for data-driven models, which is state of the art.
Journal Article

Vehicle Level Parameter Sensitivity Studies for a 1.5L Diesel Engine Powered Passenger Car with Various Boosting Systems

2015-04-14
2015-01-0982
Several diesel passenger car boosting systems were studied to assess their impact on vehicle performance and fuel economy. A baseline 1.5L diesel engine model with a single VGT turbocharger was obtained through Gamma Technologies' fast running model library. This model was modified to explore multiple two stage boosting systems to represent the anticipated architecture of future engines. A series sequential turbocharged configuration and a series turbocharger-supercharger configuration were evaluated. The torque curves were increased from that of the original engine model to take advantage of the increased performance offered by two stage boosting. The peak cylinder pressure for all models was limited to 180 bar. Drive cycle analysis over the WLTP was performed using these engine architectures, while assessing the sensitivity to various system parameters. These parameters include: vehicle weight and aerodynamic drag, EGR target maps, level of downspeeding, and turbocharger inertia.
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