AN INTERACTIVE COMPUTER-AIDED CONTROLLER DESIGN FOR AN AUTOMOTIVE ENGINE

An interactive computer-aided control system technique is utilized to design a compensator for a conventional automobile engine. The ratio of fuel mass flow to air mass flow is a very important factor in the air pollution caused by car engines. Feedback control design is used to produce an improved level of fuel to air (F/A) ratio. It is shown in this paper that for an essentially nonlinear engine, when a linear perturbation model at a nominal operating point is used, the commonly used PID controller cannot be effected satisfactorily. An alternative linearization procedure based on the Exponential Input Describing Function is utilized and an algebraic technique is applied to design a controller which meets all of the desired design specifications and satisfies imposed constraints. The new controller is shown to be less sensitive to the inevitable parameter perturbations and disturbances.