A High-Efficiency Two-Stroke Engine Concept: The Boosted Uniflow Scavenged Direct-Injection Gasoline (BUSDIG) Engine with Air Hybrid Operation

A novel two-stroke boosted uniflow scavenged direct-injection gasoline (BUSDIG) engine has been proposed and designed in order to achieve aggressive engine downsizing and down-speeding for higher engine performance and efficiency. In this paper, the design and development of the BUSDIG engine are outlined discussed and the key findings are summarized to highlight the progress of the development of the proposed two-stroke BUSDIG engine. In order to maximize the scavenging performance and produce sufficient in-cylinder flow motions for the fuel/air mixing process in the two-stroke BUSDIG engine, the engine bore/stroke ratio, intake scavenge port angles, and intake plenum design were optimized by three-dimensional (3D) computational fluid dynamics (CFD) simulations. The effects of the opening profiles of the scavenge ports and exhaust valves on controlling the scavenging process were also investigated. In order to achieve optimal in-cylinder fuel stratification, the mixture-formation processes by different injection strategies were studied by using CFD simulations with a calibrated Reitz–Diwakar breakup model. Based on the optimal design of the BUSDIG engine, one-dimensional (1D) engine simulations were performed in Ricardo WAVE. The results showed that a maximum brake thermal efficiency of 47.2% can be achieved for the two-stroke BUSDIG engine with lean combustion and water injection. A peak brake toque of 379 N·m and a peak brake power density of 112 kW·L^-1 were achieved at 1600 and 4000 r·min^-1, respectively, in the BUSDIG engine with the stoichiometric condition.

Fuzzy Control Method for Gasoline Engine Idle Speed Control

In order to improve the steady and dynamic characteristic of the idle speed control and study the performance of the fuzzy control method for the idle speed control, a fuzzy control system is developed to control the idle speed of gasoline engine. The construction and working principle of the fuzzy controller are described, and the design procedure of the fuzzy controller is given in detail. The control parameters are determined by computer simulation. The simulation and experiments on the engine test bench show that the idle speed is controlled accurately both in stationary and in dynamic states, and the fuzzy control method is robust to the changes of engine parameters.

STUDY ON INJECTION AND IGNITION CONTROL OF GASOLINE ENGINE BASED ON BP NEURAL NETWORK

According to advantages of neural network and characteristics of operatingprocedures of engine, a new strategy is represented on the control of fuel injection and ignitiontiming of gasoline engine based on improved BP network algorithm. The optimum ignition advance angleand fuel injection pulse band of engine under different speed and load are tested for the samplestraining network, focusing on the study of the design method and procedure of BP neural network inengine injection and ignition control. The results show that artificial neural network technique canmeet the requirement of engine injection and ignition control. The method is feasible for improvingpower performance, economy and emission performances of gasoline engine.

Numerical Simulation of a Spark Ignited Two-Stroke Free-Piston Engine Generator

A numerical program is built to simulate the performance of a spark ignited two-stroke free-piston engine coupled with a linear generator. The computational model combines a series of dynamic and thermodynamic equations that are solved simultaneously to predict the performances of the engines. The dynamic analysis performed consists of an evaluation of the frictional force and load force introduced by the generator. The thermodynamic analysis used a single zone model to describe the engine＇ s working cycle which includes intake, scavenging, compression, combustion and expansion, and to evaluate the effect of heat transfer based on the first law of thermodynamics and the ideal gas state equation. Because there is no crankshaft, a time based Wiebe equation was used to express the fraction of fuel burned in the combustion. The calculated results were validated by using the experimental data from another research group. The results indicate that the free-piston generator has some advantages over conventional engines.

Effects of working parameters on gasoline engine exergy balance

To improve the energy utilization efficiency of internal combustion （IC） engine, exergy analysis was conducted on a passenger car gasoline engine. According to the thermodynamic theory of IC engine, in-cylinder exergy balance model was built. The working processes of gasoline engine were simulated by using the GT-power. In this way, the required parameters were calculated and then gasoline engine exergy balance was obtained by programming on computer. On this basis, the influences of various parameters on exergy balance were analyzed. Results show that, the proportions of various forms of exergy in gasoline engine from high to low are irreversible loss, effective work, exhaust gas exergy and heat transfer exergy. Effective exergy proportion fluctuates with cylinder volumetric efficiency at full load, while it always increases with break mean effective pressure （BMEP） at part load. Exhaust gas exergy proportion is more sensitive to speed, and it increases with speed increasing except at the highest speed. The lower proportion of heat transfer exergy appears at high speed and high load. Irreversible loss is mainly influenced by load. At part load, higher BMEP results in lower proportion of irreversible loss; at full load, the proportion of irreversible loss changes little except at the highest speed.

Comparative Effect of Gasoline Formulations on Fuel Economy and Emissions of Modern GDI Engine

In this paper the effect of gasoline formulations on fuel economy and emissions were studied,aiming at exploring the optimized fuel formulation that can alleviate energy crisis and greenhouse effect to some extent.Five gasoline blends with same research octane number(RON)were designed and tested on a calibrated gasoline direct injection(GDI)engine under the mapped characteristic conditions.Test results illustrate that the optimized fuel formulation shows good superiority in fuel economy,and reduces carbon dioxide(CO2)emissions at low engine speeds with medium loads.The brake-specific fuel consumption(BSFC)decreased by a maximum value of 3.26%mainly because of the improvement of combustion velocity and the optimization of low heating value.The optimized fuel formulation simultaneously increases total hydrocarbon(THC)emissions.Nevertheless,it also markedly reduces CO2 emissions,reaching the maximum value of 2.34%.The research results can be applied practically by refineries to reduce the CO2 emissions and to alleviate the greenhouse effect.

A comparison of hydrocarbons emission from engine running 85￣＃gasoline and M－100 methanol fuel

Increasing global interest in methanoi fuel has led us to investigate the exhaust emissionsof its engine. Analysis of its inorganic and organic emissions. such as CO. NO_x and hydrocarbons(total HC) have been widely reported. This paper presents an analysis of more than 20 kinds ofhydrocarbons in the emissions obtained from a spark-ignition Shanghai car running 85# gasoline anda comparison with emission from a Santana test car running M-100 methanol fuel. A set ofenrichment method has also been described. Test results show that at the current stage of methanolengine development the concentration of individual hydrocarbon including some poisonous substancesis lower than those of normal gasoline engine.

Monolithic Catalysts with Low Noble-Metal Content for Exhaust Purification of Small Gasoline Engines

A series of low noble-metal coment monolithic catalysts for exhaust purification of small gasoline engines was investigated, and it was found that the Pt/Rh-OSM/Al2O3 （where OSM was oxygen storage material） catalyst with Ce0.5Zr0.5-MnOx（3%MnOx） OSM held low light-off temperature for CO, HC, and NO; quite wide three-way window, and outstanding thermal stability. The catalyst could efficiently comrol exhaust emission of small gasoline engines.

Combustion Characteristics and Emission of a Two-Stroke Compression Ignition Engine with Two-Stage Injection

In order to study the effect of two-stage injection on two-stroke diesel engines, a well characterized research engine equipped with electronically controlled common rail system and scavenging system was constructed. Through analysis of combustion and emissions, two-stage injection shows its advantages. Compared with the standard injection, it produces less emissions, while compared with single early injection, it expands engine operation range. Further experiments were carried out to study the influence of several injection control parameters on two-stage injection. The fuel in the first injection is used for forming homogeneous mixture. The fuel in the second injection keeps combustion, and it is the main source of smoke emissions. NO_x is formed in both combustion process caused by these two injections, and there is an optimum fuel allocation ration to produce minimum NO_x. The cylinder pressure decreases, and the combustion is depressed with the increasing of scavenging pressure. By optimizing the injection control parameters of two-stage injection, NO_x and smoke can be reduced beyond 30% simultaneously.

Turbocharging the DA465 gasoline engine

In order to improve performance of the DA465Q gasoline engine, a substantial amount of research was done to optimize its turbocharging system. The research led to the GT12 turbocharger being selected and its turbocharging parameters being settled. Based on these tests, rational matching was worked out for respective components of the turbocharging system. Results show that this turbocharger allows the engine to easily meet the proposed requirements for power and economic performance, giving insight into further performance improvements for gasoline engines.

Frequency compensation control method for opposedpiston two-stroke folded-cranktrain engine's common rail system by loop-shaping theory

A frequency compensation control method for the opposed-piston two-stroke folded-cranktrain（ OPFC） diesel engine＇s common rail system is presented as a result of the study of the loop-shaping theory. A common rail working process and the classical frequency control theory are combined to construct a frequency restriction of common rail pressure. A frequency compensator is utilized to improve the robustness of multiplicative perturbations and disturbance. The loop-shaping method has been applied to design the common rail pressure controller of the OPFC diesel engine. Simulation and bench test results show that in the condition of perturbation that comes from the effect of injection,multi-injection,fuel pumping of a pre-cylinder,and instantaneous pressure fluctuation,the controller indicates high precision. Compared with the original controller,this method improves the control precision by 67. 3%.

RIPP Grasps the Techniques for Manufacturing the Latest-Generation Gasoline Engine Oils

Recently,the gasoline engine oil developed by the SINOPEC Research Institute of Petroleum Processing(RIPP)has passed seven engine tests required by the latest-generation gasoline engine oil standard GF-6/SP.Meanwhile,RIPP has brought forward the technology for manufacture of new generation gasoline engine oil based on its own formulation meeting the engine oil standard GF-6/SP simultaneously with the international additives companies,which has eliminated the new generation gap in gasoline engine oil between China and the overseas players.

Auto-Ignition and Heat Release Correlations for Controlled Auto-Ignition Combustion in Gasoline Engines

Auto-ignition and heat release correlations for controlled auto-ignition(CAI)combustion were derived from extensive in-cylinder pressure data of a four-stroke gasoline engine operating in CAI combustion mode.Abundant experiments were carried out under a wide range of air/fuel ratio,speed and residual gas fraction to ensure that the combustion correlations can be used in the entire CAI engine operation range.Furthermore,a more accurate method to compute the residual gas fraction was proposed by calculating the working fluid temperature at the exhaust valve close timing in the experiments.The heat release correlation was described in two parts,one is for the first slower heat release process at low temperature,and the other is for the second faster heat release process at high temperature.Finally the heat release correlation was evaluated on the single cylinder gasoline engine running with CAI combustion by comparing the experimental data with the 1-D engine simulation results obtained with the aid of the GT-Power simulation program.The results show that the predicted loads and ignition timings match closely with the measurements.

Performance Evaluation of Spark Ignited Engine Fueled with Gasoline-Ethanol-Methanol Blends

In this paper, experimental investigations are presented to assess the performance variations in a single cylinder spark ignited engine when run with three different gasoline-alcohol blends： （88% gasoline-12% methanol, 88% gasoline-12% ethanol and 88% gasoline-6% methanol-6% ethanol）. Additional tests are carried out with the basic gasoline fuel for comparison analysis and performance assessment. Engine performance is investigated under a variety of engine operating conditions. The results are presented in the domain of engine speed. In particular, the brake power of the engine is shown to be slightly increased. The brake thermal efficiency showed an increase compared with the basic gasoline engine. Similarly, it is shown that brake specific fuel consumption is enhanced compared with basic gasoline engine. The exhaust gas temperature showed a decrease compared with gasoline fuel which is preferable to reduce emissions. The alcohol additives are strongly recommended to enhance performance, increasing the mileage and reducing the emissions.

Study on Using Mixed Fuel of Jet Fuel/Gasoline as Fuel of Gasoline Engine

This paper has integrated various methods such as laboratory physical and chemical analysis, engine bench test and actual road test, etc. to conduct a feasibility study on the emergency alternative fuel of gasoline by mixed jet fuel and gasoline. The study shows that both the evaporability and anti-knock quality decrease after mixing jet fuel with gasoline. While the mixing proportion increases, the engine power decreases and the fuel consumption increases gradually. When the proportion reaches 40%, the engine power drops by 5.3% to 11.7%, the fuel consumption rises by an average of 3.8%, and meantime the oil dilution and emission of the engine power become worse. Therefore, as for the gasoline engine, the mixed oil can only be used as emergency alternative fuel due to its harm to the engine.

Technologies and studies of gas exchange in two-stroke aircraft piston engine:A review

The in-cylinder gas exchange process is crucial to the power performance of two-stroke aircraft piston engines,which is easily influenced by complex factors such as high-altitude performance variation and in-cylinder flow characteristics.This paper reviews the development history and characteristics of gas exchange types,as well as the current state of theory and the validation methods of gas exchange technology,while also discusses the trends of cutting-edge technologies in the field.This paper provides a theoretical foundation for the optimization and engineering design of gas exchange systems and,more importantly,points out that the innovation of gas exchange types,the modification of theoretical models,and the technology of variable airflow organization are the key future research directions in this field.

Effect of temperature on tribofilm growth and the lubrication of the piston ring-cylinder liner system in two-stroke marine engines

This study is an optimized extension based on the authors’previous research on the tribo-chemical reaction under constant temperature field of two-stroke internal combustion engines(ICEs).It establishes a coupled analysis model that considers the tribo-chemical reactions,dynamic contact,and interface lubrication of the piston ring-cylinder liner(PRCL)system under transient temperature conditions.In this study,for the first time,the prediction of the tribofilm thickness and its influence on the surface micro-topography(the comprehensive roughness)are coupled in the working temperature field of the PRCL system,forming an effective model framework and providing a model basis and analytical basis for subsequent research.This study findings reveal that by incorporating temperature and tribofilm into the simulation model,the average friction deviation throughout the stroke decreases from 8.92%to 0.93%when compared to experimental results.Moreover,the deviation during the combustion regime reduces from 39.56%to 7.34%.The proposed coupled model provides a valuable tool for the evaluation of lubrication performance of the PRCL system and supports the analysis software forward design in two-stroke ICEs.

Application of the Computer Simulation Technique to Developing EFI Engine

The application of computer simulation technique to electronic controlled fuel injection(EFI) engine was studied to increase the development speed and improve the overall performance of the engine and car. On the basis of an EFI system developed by ourselves, the simulation model of the initial control data and engine operation points during a driving cycle and the car performance pridiction model were established. This method was applied to a mini car. The experiment showed that the simulated control data has good accuracy; and the engine test points and car performances obtained by simulation are useful for the matching of EFI system with gasoline engine and the development speed is increased.

Development of Fuel/Engine Systems—The Way Forward to Sustainable Transport

The global demand for transport energy is large, growing, and primarily met by petroleum-derived liquid fuels powering internal combustion engines (ICEs). Moreover, the demand for jet fuel and diesel is projected to grow faster than the demand for gasoline in the future, and is likely to result in low-octane gasoline components becoming more readily available. Significant initiatives with varying motivations are taking place to develop the battery electric vehicle (BEV) and the fuel cell as alternatives to ICE vehicles, and to establish fuels such as biofuels and natural gas as alternatives to conventional liquid fuels. However, each of these alternatives starts from a very low base and faces significant barriers to fast and unrestrained growth;thus, transport—and particularly commercial transport—will continue to be largely powered by ICEs running on petroleum-based liquid fuels for decades to come. Hence, the sustainability of transport in terms of affordability, energy security, and impact on greenhouse gas (GHG) emissions and air quality can only be ensured by improving ICEs. Indeed, ICEs will continue to improve while using current market fuels, through improvements in combustion, control, and after-treatment systems, assisted by partial electrification in the form of hybridization. However, there is even more scope for improvement through the development of fuel/engine systems that can additionally leverage benefits in fuels manufacture and use components that may be readily available. Gasoline compression ignition (GCI), which uses low-octane gasoline in a compression ignition engine, is one such example. GCI would enable diesel-like efficiencies while making it easier to control nitrogen oxides (NOx) and particulates at a lower cost compared with modern diesel engines. Octane on demand (OOD) also helps to ensure optimum use of available fuel anti-knock quality, and thus improves the overall efficiency of the system.

Real-time Control Oriented HCCI Engine Cycle-to-cycle Dynamic Modelling

For homogeneous charge compression ignition （HCCI） combustion, the auto-ignition process is very sensitive to in-cylinder conditions, including in-cylinder temperature, in-cylinder components and concentrations. Therefore, accurate control is required for reliable and efficient HCCI combustion. This paper outlines a simplified gasoline-fueled HCCI engine model implemented in Simulink environment. The model is able to run in real-time and with fixed simulation steps with the aim of cycle-to-cycle control and hardware- in-the-loop simulation. With the aim of controlling the desired amount of the trapped exhaust gas recirculation （EGR） from the previous cycle, the phase of the intake and exhaust valves and the respective profiles are designed to vary in this model. The model is able to anticipate the auto-ignition timing and the in-cylinder pressure and temperature. The validation has been conducted using a comparison of the experimental results on Ricardo Hydro engine published in a research by Tianjin University and a JAGUAR V6 HCCI test engine at the University of Birmingham. The comparison shows the typical HCCI combustion and a fair agreement between the simulation and experimental results.