Control of Air-to-Fuel ratio of spark ignited engine using super twisting algorithm

Mean Value Engine Model of Spark Ignited Internal Combustion Engine (fourth order) suitable for the control of Air-to-Fuel ratio has been developed. Air-to-Fuel ratio plays a key role in engine operation concerning numerous aspects of the performance. These include fuel efficiency, smooth operation, components of engine exhaust, torque output and many others. Aforementioned are aspects of performance which are prettily affected by degraded Air-to-Fuel ratio both during transient and steady state operation. Deviation of air-to-fuel ratio from its ideal value merely occurs due to difference in required mass flow rate of fuel which would, in such case, not be in proper proportion. For the purpose; super-twisting algorithm (HOSM) based controller is developed. Self convergent and inherent robust nature of super twisting algorithm proves to be advantageous in control of Air-to-Fuel ratio. Performance of the controller is analyzed against variation in different parameters of the fuel system and corresponding change in actuation of the controller is discussed.