Combustion features under different center of heat release of a diesel engine using dimethyl carbonate/diesel blend

Abstract

Experiments were performed in a single cylinder common-rail diesel engine which adopts a low temperature PCCI mode. Combustion features of DMC-diesel blends under various COHRs were revealed in details. With retarding of COHR, all the peaks of pressure and pressure rise rate and bulk gas temperature are postponed and declined in sequence. Normally, the crank angle of peak pressure is quite close to the COHR, while the peak of bulk gas temperature appears about 7 o CA after COHR as a rule. The prolongation can be demonstrated at every stage of combustion such as q 10 and q 90 with the COHR being put backward. In addition, the heat release of diesel is completely slower than that of D10 fuel at various stages. Unfortunately, retarding of COHR implies a declining thermal efficiency of engines as well as a higher cyclic variation in general. Nevertheless, D10 blend has higher thermal efficiency than diesel thanks to A c c e p t e d M a n u s c r i p t 2 high oxygen content of DMC and low boiling point which prompts better fuel atomization and complete combustion. Meanwhile, the cyclical variation of D10 is greater than diesel fuel owing to the low heat value, high latent heat of vaporization and poor flammability and of DMC. As a total, a comprehensive understanding of PCCI combustion features under different COHRs can be conducive to conducting effective management of combustion process and manipulating the subsequent emission performance to a favorable level.

Enhancing performance and reducing emissions of a spark ignition engine by adding dimethyl carbonate to gasoline

“…On the other hand, DMC-blend diesel produced higher HC and CO, and there is no change in NOx emissions. Deqing Mei et al [16] conducted experiment to investigate the combustion and emission characteristics of DMC blended with diesel in a singlecylinder CI, PCCI CRDI engine. The low boiling point of DMC produces the heat earlier, which strengthens the constant volume degree of the thermodynamic cycle;…”