A novel technology assessment chart for thermal efficiency improvement of IC engines

Abstract

Analysis of internal combustion (IC) engine measurements for thermal efficiency improvement is a complex endeavor involving a number of competing interrelated factors. To simplify the process, a novel chart and its utilization are introduced. The proposed chart divides a potential indicated thermal efficiency improvement into the contribution factors of cooling system losses and cycle efficiency. Cycle efficiency is an ideal target or goal; how much in-cylinder net heat energy, less cooling losses and unburnt fuel losses from the lower heating value of injected fuel, can be effectively transformed into indicated work? This paper explains the definition and practical usage of this chart. Furthermore, several experimental case studies involving advanced engine technologies using the chart are illustrated to identify improvement pathways and their potential effects on thermal efficiency.