Thermal efficiency can be improved with a super lean-burn. In a super lean-burn engine, combustion takes place at lower temperatures, meaning lower energy losses and much greater thermal efficiency.
In Part I (presented at PF&L 2019) [1], we studied the effects of various fuels on the lean limit in super lean-burn conditions. We found that the lean limit could be greatly extended and thermal efficiency improved with the right combination of engine technology and fuel technology. We also found that the lean limit closely linked to the duration from start-of-spark discharge to CA10, and that substances which shorten this duration extends the lean limit.
In this study, we evaluated the effects of hydrocarbons closer in composition to commercial gasoline on the lean limit and found that at the specific components, the lean limit could be much higher than that with commercial gasoline. We also studied the lean limit extension mechanism by focusing on autoignition.
