汽油机燃烧产物物性计算的一种简化方法

本文提出一种计算汽油机燃产物热力学特性的简化方法，介绍了该方法的导出过程，并对简化计算式进行了验证计算及误差分析。计算结果表明，该方法在一定的温度范围内（５００－２８００Ｋ），对燃气热物性的计算有较好的精度。     

电控汽油机提高经济性排放性的途径

本文提出了电控汽油机提高燃油经济性，降低排放的三种措施，并介绍了各种措施的一些具体要求及实施手段，为车用电控汽油机进一步提高燃油经济性，降低排放提供了途径。     

传感器热冲击效应对CA6102型汽油机示功图精度的影响

通过试验指出，在准确确定上点后，影响ＣＡ６１０２型汽油机示功图精度的主要因素是传感器的热冲击效应，而不是传感器的通道效应。简述了热冲击效应的特点，给出了ＣＡ６１０２型汽油机平均指压力随转速变化的误差修正曲线。     

基于BOOST软件对某款汽油机排气歧管的优化

利用AVL BOOST软件对某款汽油机进行了一维不稳定流动模拟计算,发现4-1的排气歧管连接方式影响发动机的充气效率.将排气歧管连接方式由原来的4-1改为4-2-1,且在不影响各缸充气效率的情况下,微调排气歧管的长度得到3种方案.通过比较功率和扭矩确定方案2为最佳方案,并按改进方案2设计排气系统进行了试验.结果表明.与原方案相比,按方案2改进排气系统后发动机功率提高,且其燃油消耗曲线更加平坦,低油耗范围扩大.     

Performance and emission characteristics of a spark ignition engine fuelled with butanol isomer-gasoline blends

The heavy reliance on petroleum-derived fuels such as gasoline in the transportation sector is one of the major causes of environmental pollution. For this reason, there is a critical need to develop cleaner alternative fuels. Butanol is an alcohol with four different isomers that can be blended with gasoline to produce cleaner alternative fuels because of their favourable physicochemical properties compared to ethanol. This study examined the effect of butanol isomer-gasoline blends on the performance and emission characteristics of a spark ignition engine. The butanol isomers; n-butanol, sec-butanol, tert-butanol and isobutanol are mixed with pure gasoline at a volume fraction of 20 vol%, and the physicochemical properties of these blends are measured. Tests are conducted on a SI engine at full throttle condition within an engine speed range of 1000–5000 rpm. The results show that there is a significant increase in the engine torque, brake power, brake specific fuel consumption and CO₂ emissions with respect to those for pure gasoline. The butanol isomers-gasoline blends give slightly higher brake thermal efficiency and exhaust gas temperature than pure gasoline at higher engine speeds. The iBu20 blend (20 vol% of isobutanol in gasoline) gives the highest engine torque, brake power and brake thermal efficiency among all of the blends tested in this study. The isobutanol and n-butanol blend results in the lowest CO and HC emissions, respectively. In addition, all of the butanol isomer-gasoline blends yield lower NO emissions except for the isobutanol-gasoline blend.     

车用汽油机过渡工况进气流量预测研究

提出了一种基于混合遗传算法的径向基神经网络(HGARBF)的车用汽油机过渡工况进气流量预测模型。首先设计了一种新的混合遗传算法,利用梯度算法每次迭代得到的结果来改进遗传算法的群体,将遗传算法的最优个体与梯度算法的迭代解相比较,选择其中的最优点作为梯度算法下一步迭代的起始点,运用该混合遗传算法进行径向基神经网络参数的优化,改善径向基神经网络不同初始参数对其性能的影响;然后建立了基于HGARBF网络的过渡工况进气流量的预测模型。仿真结果表明,该预测模型优于经典的进气流量平均值模型,为精确及时测试汽油机进气流量提供了新的方法。     

基于一维/三维模型耦合仿真的汽车进气谐振器设计

采用STAR-CD软件,建立了Helmholtz进气谐振器流体动力学模型,利用GT-POWE软件建立465Q汽油机模型,运用STAR-CD与GT-POWER软件建立了谐振器与发动机联合仿真模型,在此基础上,对谐振器和发动机进行了一维/三维模型耦合仿真,得到了谐振器对进气降噪和发动机性能的影响结果。并进行了实验对比,计算值与测量值吻合良好,模拟结果为谐振器的优化设计提供了依据。     

基于CAN总线的汽油机管理系统标定平台开发

将CAN转USB接口技术应用于发动机标定系统中,实现了标定主机和发动机各待标定电控单元之间的实时准确数据通信,具有连接简单、传输速率高和控制系统扩展性好等优点。在优化过程中采用了Bayesian算法,缩短标定时间并提高了标定精度。最后针对WF4C27F-E汽油机进行了标定试验,获取了充量系数和点火提前角MAP图。     

An assessment of gasoline motorcycle emissions performance and understanding their contribution to Tehran air pollution

Motorcycles are the third most common means of transportation in the megacity of Tehran. Hence, measurements of emission factors are essential for Tehran motorcycle fleets. In this study, 60 carburetor motorcycles of various mileages and engine displacement volumes were tested in a chassis dynamometer laboratory according to cold start Euro-3 emissions certification test procedures. For almost all of the tested samples, the average carbon monoxide (CO) emission factors were about seven times higher than the limits for Euro-3 certification. No motorcycle fell within the Euro-3 certification limit on CO emissions. 125 cc engine displacement volume motorcycles, which are dominant in Tehran, have the most total unburned hydrocarbons and CO emission rates, and they have less nitrous oxides (NO_X) emission rates and fuel consumption compared to those of larger engine volume motorcycles. Calculation of fuel-based emission factors and moles of combustion products shows that about 40% of fuel consumed by 125 cc engine volume motorcycles burns to incomplete combustion products. This proportion is lower for larger engine volume motorcycles. Approximation of relative air–fuel ratio results shows very rich combustion in selected motorcycles. Using a carburetor fuel supply system, low engine compression ratio, aging, and no catalyst could be reasons for high emission rates. These reasons could possibly result in high ultrafine particles emission rates from motorcycles. Comparison of total motorcycle pollutant emissions to that of passenger cars from previous studies in Tehran shows that motorcycles contribute to pollutant much higher than their contribution to the total fleet or total travels.     

稀燃汽油机降低NOx排放技术方案分析研究

采用吸附还原催化转化器和三效催化转化器的不同组合,对一台改装的16气门电控燃油喷射稀燃汽油机进行了降低富氧下NOx排放的实验研究。结果表明：三效催化转化器位于吸附还原催化转化器之前的布置方案具有较好的降低稀燃汽油机NOx排放的效果。