This paper illustrates the application of hybrid modeling and optimal control to the problem of air-to-fuel ratio and torque control in advanced technology gasoline direct injection stratified charge (DISC) engines. DISC engines have two discrete modes of operation, stratified and homogeneous, and their dynamic behavior can be easily captured by a hybrid model. We show that the design flow (hybrid modeling and controller synthesis) is simple in terms of problem setup and tuning, provides good closed-loop performance, and leads to a control law that can be implemented on automotive hardware as a piecewise affine function of the measured and estimated quantities.