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Technical Paper

DI Diesel Engine Combustion Modeling Based on ECFM-3Z Model

In recent years, with the development of CFD technology, numerical simulation is becoming an important method to study the in-cylinder spray and combustion process of internal combustion engine. Consequently the appropriate selection of mathematical models is very important, which will determine directly the accuracy of calculation results in IC engine numerical simulation. In this paper, the EDC and ECFM-3Z combustion model was introduced respectively, and the latter was emphasized on. Finally it was decided to use ECFM-3Z model to simulate the combustion process of a 4-valve DI diesel engine for its advantages. Through comparison and analysis, it is found that the computation results of the in-cylinder pressure peak, RoHR and emission products have excellent agreement with experimental data. Accordingly the research results show that the ECFM-3Z model reveals the DI diesel combustion process closely, and forecasts the formation of exhaust emissions accurately.
Technical Paper

Numerical Simulation and Experimental Study of Mixture Formation and Combustion Process in a DI Diesel Engine

In the present study, an improved multi-dimensional CFD code has been used to simulate the mixture formation and combustion process of a DI diesel engine. WAVE breakup model constants C0 and C1 are modified according to a linear expression, which is a function relation to the gas pressure in-cylinder. Reasonable agreements of the measured and simulated data of in-cylinder pressure, mean temperature, NOx and soot emissions were achieved for different engine operation conditions. At the same time, the effects of different spray angles on the diesel engine mixture formation and combustion have been further simulated based on the improved multi-dimensional fuel spray and combustion models. The influence of different testing conditions mentioned above on the PM and gaseous pollutant was also discussed in this paper. Predicted trends of soot and NOx formation are also presented together with the corresponding measured data.
Technical Paper

Experiments of Methanol-Gasoline SI Engine Performance and Simulation of Flexible Fuel Characteristic Field

Due to the oil crisis and the requirements of energy saving and emission reduction, the research of alternative energy sources for sustainable development has made good progress. Methanol has proven to be a very suitable alternative clean fuel. Compared with gasoline, methanol has a wide range of source and the higher oxygen content and octane number and combustion efficiency, which are beneficial for the engine performance. The effect of different proportions of methanol-gasoline mixed fuel on the performance of SI engine was studied experimentally (lower proportion and higher proportion). It was found that the engine power performance, fuel economy and exhaust emissions were related to the methanol ratio under different operating conditions. In order to adapt to different operating conditions to improve the performance of methanol-gasoline engine, an on-board flexible fuel mixed system was proposed.
Technical Paper

Simulation Investigation of Working Process and Emissions on GDI Engine Fueled with Hydrous Ethanol Gasoline Blends

Compared with ordinary gasoline, using ethanol gasoline blends as fuel of Internal Combustion Engine is beneficial for the performance of power, economy and emission of engine. However, the fuel ethanol blended in ethanol gasoline blends currently is usually anhydrous ethanol, which requires dewatering implementer in production process, and the cost is high. Therefore, the production cost can be significantly reduced by replacement of anhydrous ethanol with hydrous ethanol while exerting the advantage of ethanol gasoline blends. In this study, computation fluid dynamics (CFD) software CONVERGE is employed to establish a simulation model of an actual gasoline direct injection (GDI) engine, and investigate the effect of burning hydrous ethanol gasoline blends and different injection strategy on combustion process and emission, and the validity of the model was validated by experiments.
Technical Paper

Gasoline Engine Turbocharger Matching Based on Vehicle Performance Requirements

Turbocharger is an important method to improve fuel economy of internal combustion engines. Traditional turbocharger matching methods show their limitations that only consider the matching between turbocharger and engine under the single designed operating point. This paper is to study the turbocharger matching based on vehicle performance requirements, in which performance requirements among vehicle, engine and turbocharger system are fully considered. The study is based on a vehicle which is equipped with 1.5L Chinese produced engine. Vehicle powertrain and gasoline engine simulation models were built in one-dimensional simulation software and verified by experiments. According to the vehicle performance, to study the matching under multiple working conditions, new European drive cycle (NEDC), full-load condition and high altitude condition, the matching of four kinds of turbochargers with a gasoline engine were compared respectively.
Technical Paper

Research on Effect of Wastegate Diameter on Turbocharged Gasoline Engine Perfor mance

Boosting and downsizing is the trend of future gasoline engine technology. For the turbocharged engines, the actuation of intake boosting pressure is very important to the performance output. In this paper, a GT-Power simulation model is built based on a 1.5 L turbocharged gasoline engine as the research object. The accuracy of model has been verified through the bench test data. Then it is conducted with numerical simulation to analyze the effect of wastegate diameter on the engine performance, including power output and fuel economy. Mainly the wastegate diameter is optimized under full engine operating conditions. Finally an optimal MAP of wastegate diameter is drawn out through interpolation method. By the transmission relationship between wastegate and actuator, a wastegate control MAP for electric actuated wastegate can be obtained.
Technical Paper

Effect of Hydrous Ethanol Combined with EGR on Performance of GDI Engine

In recent years, PM emission from GDI engines has been gradually paid attention to, while the hydrous ethanol has a high oxygen content and a fast burning rate, which can effectively improve the combustion environment. In addition, EGR can effectively reduce engine NOx emissions, and combining EGR technology with GDI engines is becoming a new research direction. In this paper, the effects of hydrous ethanol gasoline on the combustion and emission characteristics of direct injection engines are analyzed through direct injection engine bench test. The results show that the increase of the proportion of hydrous ethanol accelerates the combustion rate, shortens the combustion duration, and peaks the cylinder pressure and heat release rate. At the same time, the combustion efficiency is improved. The hydrous ethanol gasoline can effectively improve the gaseous and PM emissions of the direct injection engine.