The Study On Optimization Of The Electronic Controlled Gasoline Injection System For 491Q Engine

According to the importance of environmental protection, saving energy and using in our country, a electronic controlled gasoline multi-point injection system developed by author for automobile 491Q engine introduced from foreign country is presented in this dissertation. 491Q engine is optimized and matched by the system. It is composed of air system, fuel system and control system. Taking a series of controlled parameters as the inputs through some sensor, such as MAP(Manifold Absolute Pressure sensor), CPS(Crankshaft Position Sensor), MAT(Manifold Air Temperature sensor), CTS(Coolant Temperature Sensor), TPS(Throttle Position Sensor) and OS(Oxygen Sensor), the system controls the air-fuel ratio and ignition advance according to the controlled parameter maps stored in the memory of ECU. During the control process, the system adopts the proper control strategy in accordance with the operating mode as start, idle, acceleration, deceleration, and cruising mode in which the engine is working, and therefore the different needs for air-fuel ratio and ignition advance in various operating modes can be met. Owing to the grouping synchronously multi-point injection, the distributorless ignition system with two cylinder ignited synchronously, and MAP sensor replacing air flow meter are applied in this system., it has simple structure, credible performance and cheap cost.Influence of engine performance with ignition advance and air-fuel ratio was discussed and studied in detail. On the basis of the Thermodynamics Models on gas engine combustion, combustion simulation program in gasoline was compiled with Visual Basic 6.0. Running the program, the law of pressure rise and discharge heat in combustion, propagating speed and frontside area of flame were simulated. With a good deal of calculation for engine power performance and fuel economy, the generic law of controlling ignition advance and air-fuel ratio was theoretically concluded.The injurant in vehicle exhaust and its influence are analysed in detail, and the stringent increasingly exhaust law in automobile in-out of the nation is expatiated. So it is essential to apply electronic controlled fuel injection system and it is an important role in all means by which exhaust is reduced to make good use of electronic technology.The design features of inlet system are described in this dissertation. The factors influencing intake efficiency such as intake dynamic action and manifold structure parameterswas analyzed in order to increase intake efficiency. A specialized manifold for the multi-point injection system was designed and matched with original engine according to the requirements for assemble and technics. Additionally, many compute method on the intake system were introduced for design effect can be validated by this method.The optimization calibration of control parameters was described emphatically in this dissertation, the different operating modes often happen in which the engine is working, so every mode must be calibrated in order to receive accurate control. Calibration processes are illuminated in accordance with the operating modes such as stabilization, intergradation, start and in altiplano and cold area. On the basis of lots of experiment, the result of calibration is received.Finally, after the system was applied to the 491Q engine and automobile, the dynamometer tests of engine and the on-road tests of automobile were performed comparing with original engine to testify the effect of calibration further. The test results showed that the power performance was improved, emission can be met as Eu- II and technological performance is enough well to meet the requirements for vehicle at present.