Development Of The Gasoline Engine And Performance Optimization Base On Atkinson Cycle

So far, global petroleum crisis has erupted three times in a row, the shortage of energy threatens the development of mankind society and the environmental pollution caused by fossil fuels, has become the widely concerned topic in the international community. Energy conservation and emission reduction is increasingly the focus of governments work and vehicle industry is facing new challenges as a large petroleum consumer. Hybrid cars become the trend of vehicle development in short future, since internal combustion engine can’t make a breakthrough in oil-economizing technology and electric vehicle is limited by its underdevelopment. The hybrid cars on the market began to widely use Atkinson cycle engine, its inherent advantages in cyclical theory is a new way to break the Otto cycle’s technical bottleneck in economy.In this paper, based on a hybrid energy conservation and emissions reduction requirements, I redesign an existing Otto cycle engine to Atkinson cycle with minimal changes, and to attain the goal of energy conservation and emissions reduction for a greater degree. Paper main research work and innovation are as follows:(1) This thesis discussed the difference between the traditional Otto cycle and Atkinson cycle from the aspect of theory. Then put forward the redesign retrofit with the full analysis of the prototype engine structure and working process. And focus on flexible use of double VVT to further optimize the Atkinson cycle engine performance.(2) Put forward the scheme that the throttle valve work together with cylinder intake and exhaust valves to control load distribution. For the limit of the VVT range, this machine kept the throttle at the small load condition and throttle fully open under heavy load conditions to reduce the loss of throttling, and get the changing rule of throttle and VVT Through software simulation.(3) Bench calibration test of the modified engine was carried out based on the software-optimized parameters, like valve timing, ignition angle and air-fuel ratio. Comparison between the test results and the software simulation data shows that they have identical results, and the improvement scheme has reached the expected goal.