Design and Experimental Testing of a Novel Skip-Cycle Mechanism for Wankel Engine

Abstract

In this study a new skip-cycle mechanism which will be applied to the Wankel engine have been designed, analyzed and tested. With skip-cycle method application, after the four periods of power generation are completed, no more work is produced in the following cycle. To achieve this, the fuel and ignition are cut off during the cycle when power is not generated. Additionally, in this cycle the intake port is also closed. The aim of this application is to change the effective stroke volume of the engine according to load conditions thus reducing the pumping loss and increasing efficiency. Alternative mechanisms have been designed, analyzed and one of them with minimal modification is tested on the single rotor Mazda 13B test engine. In the designed system of skip-cycle, it has been intended to stop the intake operation with the aid of a rotary valve placed in the intake port thus providing cycle control. A correlation between the moving parts on the engine has been developed with the inclusion of the valve into the mechanism. Valve window angle, valve orientation and valve window geometry parameters were evaluated. The skip-cycle mechanism was installed in the test engine and measured data of the skip-cycle and normal cycle were compared. The result show that the Wankel engine with skip-cycle mechanism runs at low load conditions with higher pressure during combustion period and lower vacuum pressure at intake period compared at equal power generation at normal cycle conditions.