Testing of a Modern Wankel Rotary Engine - Part III: Firing Condition Analysis

Abstract

This work represents a further contribution to reporting experimental activities carried out on a modern Wankel rotary engine. Specifically, in this study, the firing performance of the Advanced Innovative Engineering 225CS engine is analysed. Preliminary presentations of the experimental and measurement setup and a motoring analysis were extensively covered in Part I and II of this suite of papers while the current work presents the combustion analysis of the firing indicated pressure cycles collected through the bespoke combustion analyser software developed within the project. With the Wankel rotary engine gaining popularity again due to its potential as a range extender for battery electric vehicles, the aim of this work was mainly to analyse the fuel consumption together with the overall efficiency and the emissions at different engine speeds and loads as per classic steady-state engine testing. The characteristic curves of power and torque thus derived from the experimental measurements are reported while further deductions on combustion phenomena are then drawn from an analysis of the indicated pressure cycles. Specifically, parameters such as the rate of heat release, the net heat release, the IMEP and the indicated instantaneous torque are assessed. Further considerations are drawn on the overall mechanical efficiency relying on the IMEP computed from the indicated pressure cycles and the BMEP inferred from the torqued measured experimentally under steady-state conditions. Furthermore, the effects of the combustion on the internal pressure of the Self-Pressurizing Air-Rotor-Cooling System employed are evaluated in addition to parameters such as the Coefficient of Variation of the IMEP for the evaluation of the cycleto-cycle combustion quality and engine regularity. Finally, the postprocessed data represent an update to the historical literature on Wankel rotary engines. In addition, it can be used for the development and validation of numerical models for such engines hence allowing investigation by means of simulations of the effect on efficiency and performance of the rotary engine when employing alternative fuels such as hydrogen in the future.

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

“…Furthermore, the results presented in this study and the comparison of some of them with those collected on a Mazda 13B engine will help the niche community of rotary engines in their current and future investigations. Undoubtedly, all the relevant parameters defined in this study are considered to be the necessary starting point for the correct analysis of the engine in firing conditions that will be carried out in the part III [56] of this suite of papers.…”

Testing of a Modern Wankel Rotary Engine - Part IV: Overall Mechanical and Thermal Balance

“…The University of Bath and the IAAPS research group, as the academic partner of the ADAPT-IPT project, tested the AIE 225CS 10/19/2016 engine at their laboratories. The experimental testing was carried out mainly at steady-state conditions with some additional investigations on the emissions during the engine start and stop, as also reported in [11,12,16].…”

“…As also extensively reported in the previous papers of this suite [11][12][13], the torque and power of the engine were collected by means of a standard active dynamometer and an HBM torque flange connected to the engine by means of a rubber-damped propeller shaft in order to reduce the torsional vibrations. An illustration of the engine installed on the test bench is shown in Figure 3.…”

“…Specific research activities on the engine were carried out at the University of Bath within the IAAPS research group where several aspects of the machine were considered and evaluated: the engine was experimentally tested while numerically modelling the kinematics 10/19/2016 and fluid dynamics together with the assessment of specific control strategies, emissions and special configurations. The engine was tested in steady-state motoring and firing conditions [11][12] using a bespoke experimental plan, data acquisition system and combustion analyser [13]. Subsequently, given the flexibility of the GEMS electronic control unit employed, specific engine control strategies were developed and implemented to reduce both the fuel consumption and emissions of the engine [14,15] assessing those parameters at steady-state operating conditions and during the start and stop of the engine [16].…”

Investigations into Steady-State and Stop-Start Emissions in a Wankel Rotary Engine with a Novel Rotor Cooling Arrangement

“…Compared to a conventional reciprocating engine, in which a single pressure transducer can see the pressure in the cycle at all times, this is not a trivial task in a Wankel engine with its constantlymoving working volume. The equipment used and method of constructing the indicator diagram is not discussed further here; instead the subject is dealt comprehensively with in other publications [15,16,17] to which the reader is referred. It was, however, this approach that let the information shown in Figure 4 be gathered, with all of the measurements being taken at 341.3 kHz.…”