Fuel Saving Potential Study Of Atkinson Cycle Applied On An Automotive Gasoline Engine

In traditional Otto Cycle Gasoline Engines load is adjusted through a throttle inthe form of fresh charge "quantity" control. In city driven conditions, the intakethrottling loss is significant, it causes inevitable pumping loss and leads to increase offuel consumption, reduces potential of a hybrid vehicle energy saving and emissionreduction. Atkinson cycle could be realized through VVT control Atkinson cycle.Compared to Otto cycle, at part load conditions, pump loss can be reduced if usinginlet valve timing to control the load instead of the traditional throttle. In contrast,Atkinson cycle has high thermal efficiency due to greater expansion ratio thancompression ratio, so it can transform larger fortion of heat energy into mechanicalenergy, improve engine thermal efficiency and reduce the fuel consumption.Combine numerical simulation with experimental validation, the correctness ofgasoline engine simulation model was validated. The compression ratio and valvetiming were studyed on engine performance parameters influence. Besides, the optimaldesign strategy of improving the economy and power performance was advanced. Themain research and innovation of the article include the following works：(1)A four cylinder gasoline engine simulation model was built. The GT-POWERsimulation model was celibrated with experimental data and the correctness of modelwas validated.(2)The fuel saving potential of eliminating the pumpling loss was theoretiallyanalyzed. Several new parameters were introduced to reduce the fuel saving ratio.Then, a formula of describing fuel saving potential was deduced. The fuel saving ratioequals to pumping loss elimination rate times the pumping loss energy consumption.(3)Based on engine test data, the related parameters of fuel saving ratio wascalculated. Based on the experimental data and the theoretical derivation, the energysaving potential MAP of the Atkinson cycle was developed and analyzed. Based onthat, the most of ten operating area of an automotive engine was identified. Thedynamic distribution law required by the Atkinson engine which is applied on thehybrid vehicle was acquired.