Influence of Hydrogen Additives on Cycle-to-Cycle Variability of Working Process of Rotary Engine

Abstract

A rotary engine, designed according to Wankel’s scheme, is the one of alternative options for traditional piston ones. However, the Wankel engine has incomplete combustion of an air–fuel mixture in the working chamber which prevents the widespread use of such engines. Hydrogen additive to the main air–fuel mixture helps to decrease the incompleteness of combustion in the volumes near an apex of the rotor. In this paper, the cycle-to-cycle variability of the Wankel engine fueled with additions of hydrogen to the main air–fuel mixture at different excess air ratios was experimentally investigated. The investigation was carried out on the rotary engine VAZ-311 (Russia) equipped with the injection system of hydrogen additive. In this study, the Wankel engine was operated on part loads at the frequency of eccentric shaft 2000 rpm and different excess air ratios varied from 1 to 1.3. The results of the study showed that adding hydrogen to the air–fuel mixture allows increasing the maximum pressure in the rotary engine working chamber and improving the stability of the combustion process. The addition of 5% hydrogen at the excess air ratio of 1.2 improves combustion stability on 59.8% on the mode of the averaged urban cycle.