Testing of a Modern Wankel Rotary Engine - Part II: Motoring Analysis

The present work represents the continuation of the introductory study presented in part I [11] where the experimental plan, the measurement system and the tools developed for the testing of a modern Wankel engine were illustrated. In this paper the motored data coming from the subsequent stage of the testing are presented. The AIE 225CS Wankel rotary engine produced by Advanced Innovative Engineering UK, installed in the test cell of the University of Bath and equipped with pressure transducers selected for the particular application, has been preliminarily tested under motored conditions in order to validate the data acquisition software on the real application and the correct determination of the Top Dead Centre (TDC) location which is of foremost importance in the computation of parameters such as the indicated work and the combustion heat release when the engine is tested later under fired conditions. In this testing phase much importance has been given also to the measurement of the frictions at the different operating rotational speeds. Interestingly, the data have been collected at three different coolant temperatures, 30°C, 60°C and 90°C respectively, in order to investigate and quantify any possible effect and interaction of the heat transfer on the mechanical and thermodynamics engine parameters for the usual operating temperature range. The collected data are subsequently used for the determination of the Friction Mean Effective Pressure (FMEP) to be employed in the computation of the Brake Mean Effective Pressure (BMEP) from the indicated pressure cycle or in the numerical models created for simulation purposes. Finally, still by means of the analysis of the indicated pressure cycle, further considerations are drawn on the thermo-fluid dynamics interactions of the three moving chambers with the self-pressurizing air-cooled rotor system (SPARCS) with its details already described in the first part of this suite of papers.