Thermodynamic Efficiency Evaluation of an Indirect Injection Diesel Engine 790039
The lower efficiency of the indirect-injection diesel engine, with respect to the direct injection type, is due to additional heat transfer from the combustion chamber, gas pumping between chambers, later injection timing and a different burning rate schedule.
The paper describes a project to isolate and quantify these reasons for low efficiencies, using a mathematical model, supported by experimental verification.
The model is based on a two-zone system (main and pre-chamber), with component models for heat transfer, gas flow through the passage etc. Experimentally derived heat release schedules in main and pre-chamber are used.
It is shown that for a 0.1 m bore engine, with a Ricardo Comet Vb pre-chamber, the different burning rate schedule is the major contribution to the difference in efficiency, with injection timing and gas pumping being the least significant.