In this paper, an event-based dynamic gain-scheduling controller was designed by employing a standard control structure of observer-based state feedback with integral control. The dynamic gain-scheduling controller was applied to an LPV system representing the air-to-fuel ratio control of a port-fuel-injection process. The system parameters used in the engine fuel system model are engine speed, temperature, and load. The static gains of the dynamic gain-scheduling controller for the obtained LPV system were then designed based on the numerically efficient convex optimization (or LMI) technique. The simulation results demonstrate the effectiveness of the proposed scheme.