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Accurate Prediction of Charging Characteristics of a Four-Stroke Cycle Engine with High EGR Rate

高EGR率四冲程发动机充气特性的准确预测

基本信息

批准号：
07650254
负责人：
SHIMAMOTO Yuzuru
金额：
$ 1.34万
依托单位：
The University of Shiga Prefecture
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07650254/
关键词：
Internal combustion Engine Recirculation of Exhaust Gas Intake and Exhaust systems Gas Flow Analysis Shock Wave Performance Prediction False Diffusion

项目摘要

The technique of exhaust gas recirculation (EGR) is available for NOx reduction of gasoline and Diesel engines. The objects of research are to predict numerically EGR rate and also to estimate the differences in EGR rate between cylinders. The results obtained are as follows :1. The EGR rate has been predicted in a 4-cylinder four-stroke cycle gasoline engine with high EGR system, using the characteristic method to analyze one-dimensional gas flow unsteadily. It has been validated from the comparison between the predicted results and the experimental data that this method is usual to investigate the differences in EGR rate between cylinders. It has been founded from the investigation of the gas flow in EGR systems that the differences in EGR rate between cylinders are produced not noly owing to the geometry of pipe system but also owing to the gas dynamics in intake and exhaust systems.2. The behaviors of exhaust gas content and gas flow in intake and exhaust systems have been simulated with much less numerical diffusion by the characteristic method, in which two kinds of meshes are prepared. Much less numerical diffusion error is confiumed through the comparison between the predicted EGR rate and the experimental one. In order to improve the simulation accuracy of the unsteady gas flow in intake and exhaust system, it is important to incorporate shock wave schemes into the calculation program of gas flow in pipe systems. However, the calculation program with shock wave schemes has not yet completed owing to the complexity of program. Effort to complete the program is continued to the next year.

废气再循环（EGR）技术可用于汽油机和柴油机的氮氧化物减排。研究的目的是数值预测废气再循环率和估计不同缸间废气再循环率的差异。得到的结果如下：1。采用特征法对一维非稳态气体流动进行分析，对具有高EGR系统的四缸四冲程循环汽油机的EGR速率进行了预测。通过预测结果与实验数据的对比，验证了该方法是研究不同气缸间EGR率差异的常用方法。通过对EGR系统内气体流动的研究发现，缸间EGR率的差异不仅与管道系统的几何形状有关，还与进排气系统的气体动力学有关。采用特征法模拟了进、排气系统中废气含量和气体流动的变化规律，并采用两种网格进行了数值模拟。通过与实验值的比较，证实了数值扩散误差较小。为了提高进排气系统非定常气体流动的模拟精度，在管道系统气体流动计算程序中加入激波格式是十分重要的。然而，由于程序的复杂性，激波格式的计算程序尚未完成。完成该计划的努力将继续到明年。