Thermal Efficiency Improvement for a Diesel Engine Achieved by High-Heels Heat Release Rate Profile

Abstract

A novel heat release rate profile named ‘High heels’, which is formed by gradually increased heat release rate in two steps to retard the peak at the timing of higher volume-change rate, was proposed as a measure to practically maximize thermal efficiency of diesel combustion in lieu of the ideal thermodynamic cycles. In this study, a newly developed variable injection rate shaping system for a single injector was installed in the tested engine. The results indicated that significant reduction in cooling loss and increase in thermal efficiency were simultaneously achieved with ‘High heels’ like heat release rate profile, as expected.