Wankel rotary engines are becoming an increasingly popular area of research with regard to their use as a range extender in the next generation of Hybrid Electric Vehicle (HEV). Due to their simple design, lightness, compactness and very favourable power-to-weight ratio, they represent one of the best alternative solutions to classic reciprocating piston engines. On the other hand, current Wankel engines still need improvements in terms of specific fuel consumption and emissions.
This paper describes an innovative approach for the assessment of the performance of a modern rotary engine. All the experimental activities will be carried out within the Innovate UK funded ADAPT Intelligent Powertrain project led by Westfield Sportscars Limited. The engine under test is a 225cm3 rotary engine produced by Advanced Innovative Engineering (AIE) UK Ltd. equipped with the patented Compact SPARCS (Self-Pressurising-Air Rotor Cooling System) technology that uses the blow-by gases of the combustion process to improve the heat rejection from the rotor to the liquid coolant.
The descriptions of the experimental activities and of the test rig are provided, including the instrumentation, the gas analyser for emissions evaluation and the entire data acquisition system designed to fulfil the aims of both assessing the baseline performance and calibrating the engine. Subsequently different software tools have been developed for a detailed study on the placement of four fast-response pressure transducers used to implement a complex measurement system for acquiring the engine’s indicated pressure cycle in a real-time fashion. The data collected by the pressure transducers are also used to assess seal leakage from chamber to chamber and blow-by from chamber to the engine core. The engine is also equipped with a high-speed encoder in order to relate the angular displacement of the eccentric shaft to the volume of the chambers. Then the pressure traces can be visualized on a time-base or related to the chamber’s volume in a classic pressure-volume closed diagram. In order to improve the emissions of the engine the lubrication system is also investigated; the lubricating oil mass flow rate will be measured by means of a low-flow Coriolis mass flow meter in the range of 0.5 to 3.2ml/min. Finally, all the data from the experimental activities will support the development of 1D to 3D numerical models of the engine.