基于实测数据的汽油机无进气节流损失的节油潜力研究

Fuel saving potential of gasoline engine without throttle based on testing data

对比Otto循环与Atkinson循环,从理论上分析了后者在无节气门节流损失时发动机的节油潜力及原因,提出评定节油率的相关参数为泵气损失能耗比与泵气损失消除率;推导出节油率的计算公式;进行发动机台架试验,测量计算节油率所需要的相关参数。基于理论推导与实测数据计算得到发动机万有特性上Atkinson循环的节油潜力MAP图,并对其进行评定,得出节油效果好、实际应用性强的发动机工况区域。结果表明:当转速不超过3 000 r/min和平均有效压力不超过0.3 MPa时,节油率都在14%以上。

The pumping loop and pumping losses of a naturally aspirated gasoline engine running on conventional Otto cycle were compared with idealized Atkinson cycle. The fuel saving potential of adapting the idealized Atkinson cycle to eliminated the intake throttling losses was demonstrated based on thermodynamic process analysis to pumping loop, and the portion of pumping loss over the total mechanical work of the cycle and the presentation of pumping loss could be reduced by replacing the throttle via later intake valve closure. Fundamental equations were introduced to demonstrate the above analysis. Engine bench tests were conduced and the fuel saving potential was analyzed for the engine operational map. Analysis results indicate that the researched engine has over 14% of fuel saving potential within the engine speed range below 3 000 r/min and brake mean effective pressure below 0.3 MPa.