Optimal idle speed control of an automotive engine

An optimal control algorithm is derived to solve the idle speed control problem for an automotive engine. The system describing the engine dynamics during idle consists of nonlinear algebraic-ordinary differential equations with variable-time-delay element. Unlike many previous studies, no approximation is made to the variable-time-delay term in the equations. Instead, we use a special procedure to compute this variable-time-delay term accurately. The results show that the optimal control algorithm derived can deliver highly efficient controls to the system. Compared with the conventional control methods, the optimal control algorithm provides a versatile and systematic way to idle speed control of automotive engines.