Study On Control Method Of Gasoline Engine Oxygen-enriched Intake Air Based On MAP

Energy and environment are essential for human survival, energy shortage and environmental pollution have become obstacles to society sustainable development for the time being. The automobile brings not only mankind civilization progress but also a lot of resource consumption and serious environmental pollution. Rich oxygen combustion technology could increase the the O2volume fraction, and then improve the combustion condition and promote the dynamic performance. As a result, the rich oxygen can decrease the HC and CO emission, but it also brings the high emission of NOx. Therefore, this paper presented the oxygen-enriched intake air control method based on MAP through an air-cooling four stroke gas engine, which through study the oxygen volume, to define the controlled combustion, and then optimize the dynamic performance, economical performance, and emission performance, and finally decreace the exhaust gas. The main contents are shown as follows:(1) According to foe injection control and ignition and EGR controlled method, this paper puted forward the MAP control method, then established the test system and bench test system. In additional, the hardware control platform and the software system based on C have been designed.(2) This paper proposed the oxygen-enriched MAP test method base on the module and diagram. Influence of intake MAP static control parameters and dynamic parameters for control effect is also disscused. The intake oxygen volume fraction control quantity is revised at first, and then the dynamic revise is carried out of static MAP diagram according to the throttle percentage change rate, so the dynamic MAP control for oxygen-enrich intake is achieved. Furtherfore, the valve ration of MAP is defined base on the construction.(3) The intake oxygen control quantity is defined according to the PWM based on the various MAP control goals, and the dynamic MAP, economical MAP, emission MAP and comprehensive MAP are produced. Moreover, universal characters curve in torque, oil consumption, HC emission, CO emission and NOx emission curve is drawed. The different type intake MAPs are optimized through double three insert method, and then get the oxygen volume controlled quantity for full condition, so the dynamic intake insert MAP, economical MAP, emission MAP and comprehensive MAP are produced.(4) Promote the various combined control trageies based on MAP, and produce the combined intake initial MAP diagrame and insert MAP diagrame, and the universal character experiment for gasoline is carried out based on it. The result shows that, the largest torque increases12.94%, the least fuel consumption decreases17.05%, the least HC emission decreases11.65%, and the CO is13.89%, furthermore, the least NOx emission increases7.55%. The experimental syatem is stable, and the largest control error is±1.5%, average control error is±0.5%, the largest response time is short than6s and the average response time is short than5s.(5) Normal intake and oxygen-enriched intake MAP control are adoptted to verification test for the engine characters in speed, load and universal according to the different control goals of oxygen-enriched intake MAP. Moreover, the compration analysis of the torque, fuel consumption, HC emission, CO emission and NOx emission for gasoline engine are also carried. The verification results show that, the dynamic intake MAP could promote the dynamic performance largely of gasoline engine, the economic intake MAP could promote the economic performance largely of gasoline engine, the emmission intake MAP control could promote the gas economical performance of gasoline engine and the combined intake MAP could promote the gas comprehensive performace of gasoline engine, respectively.