Software Adaptive Method to Determine the Mechanical Stop Limits to Improve the Drivability and Emission Optimization in Two Wheeler

The present paper focuses on a system and an appropriate controller concept for an advanced air management system of gasoline small engines. In motorcycles, now a days engine management systems (EMS) are most commonly used. However, increasing demands for improved fuel efficiency and tighter legislations for reduced emissions have made it inevitable to adopt EMS parameters in small gasoline engines motorcycles which are already fuel-efficient.

During steady state operation stringent requirements of modern air/fuel ratio (AFR) control strategies, the accuracy of models needs to be better than ever. The model inputs play vital role in deciding the accuracy of AFR control and engine performance. In control software design components mechanical stop limits will be fixed by considering the worst-case tolerances (includes mechanical tolerance, manufacturing tolerance, mounting tolerance, electrical tolerance etc.). These fixed mechanical limits will lead to compromised performance and affects emissions due to difference in actual limits value and fixed limits value in engine control unit (ECU) for each component. In engine management system (EMS), the position of lower mechanical stop (LMS) and upper mechanical stop (UMS) of accelerator position sensor (APS) and throttle position sensor (TPS) play a key role in controlling engine operation. These limits will determine the engine states such as idling, full load, transient conditions etc. So continuous adaptation of these mechanical limits will be crucial for robust engine control and manage optimized vehicle parameters. Also, software adaptive methods required to determine these limits to counter the sensor aging, sensor component failures, component replacements etc.

The limits adaptive method proposed in this paper provides accurate and continuous limits information along with current position value for engine control parameters. Adaptive SW method also covers to handle the mis-adaptation due to various factors and sensors failure scenarios. This method can be deployed for any type of position sensor such as APS, TPS etc. Accurate air mass flow calculation will be achieved by knowing exact limits position of throttle angle for respective engine by this adaptive method. Estimation of air mass in combustion chamber decides pre-control value to maintain stochiometric ratio and combustion quality of gasoline engine along with ignition set value.