【作者】 穆卫强；

【导师】 周大森；

【作者基本信息】 北京工业大学 ， 热能工程， 2003， 硕士

【摘要】 本研究主要针对GY6系列125ml坐式摩托车发动机，开发出一套电控燃油喷射加三元催化器闭环控制系统。将该系统应用于发动机，在LZDC-15型直流电力测功系统上对控制参数进行了标定，并以此为基础与原机的动力性、经济性和排放特性进行了对比实验。在研究开发过程中借鉴了目前已广泛应用于汽车发动机上的电控燃油喷射的成熟技术，对其进行适当改动和精简，以达降低系统成本的目的，使新系统能够适应在摩托车发动机上的应用。系统中对空燃比的控制没有沿用通常的控制方式，而是采用了占空比控制方式，这使控制系统的硬件和软件都得到了简化，提高了系统的稳定性和抗干扰能力。在研究中还提出了通过喷油器喷油特性估算燃油消耗量的方法，解决了电喷系统油耗难于测定的问题。实验证明本系统可以精确控制可燃混合气空燃比，配合三元催化器使用后使排放得到了大幅度降低，同时平均功率和扭矩比原机都有所提高，油耗降低。利用系统可以精确控制空燃比的特性，在实验中还对氧传感器进行了标定，获得了所用氧传感器的特性曲线。将这套系统应用于摩托车，可在整车成本提高不多的情况下，大幅度提高发动机的动力性和经济性，降低排放，提高整车的技术水平。而且该系统经适当的技术匹配后可应用于绝大多数摩托车发动机，具有良好的应用前景。更多还原

【Abstract】 In this study we developed a closed-loop electric control system，which used Electric Fuel Injection (EFI) and Three Way Catalyst converter (TWC) technology，on GY6 125ml scooter engine．We selected the controls parameter of the system on LZDC-15 direct current electrical dynamometer system．Then on the base of this work we do some experiments to compare the power，the economy and the emission performance with the original engine．During the research we used the EFI technology，which used on the automobile engine as a reference．But this technology can’t be used on the motorcycle directly because of its high cost．So in order to lower down the cost of the system，we do some modification and simplification work on it．After the modification，the system can be fit for the application on the motorcycle very well．In the system we don’t use the common method to control the A/F．We adopt a new one，which called the duty-ratio-control method to do so．By using this kind of method we can simplify the hardware and the software and enhance the stability and anti-jamming performance of the system．In the research we also use a new method to estimate the fuel consumption of the engine．It is very hard to measure the fuel consumption of the EFI system directly．But we must get the data to compare with the original engine．After some study we found that through the characteristic of the nozzle we can estimate fuel consumption．By this way the problem has been solved．It has been testified by the experiment that the system can accurately control the A/F of the flammable mixture．Using together with the TWC，the system can lower down the emission of the engine greatly．At the same time the average power and torque are higher and the fuel consumption is lower down than before．Because the system can control the A/F accurately，we use it to get the output characteristic curve of the oxygen sensor．Through applying this system on motorcycle we can enhance the power and economy and lower down the emission performance of the vehicle．On the other hand the cost does not raise more．After some matching work the system can be applied on almost all kinds of motorcycle engines．We trust that the system has a good future．更多还原