The design of a torque tracking controller for a spark ignition engine is presented. A hybrid model that describes the interacting behavior of the intake manifold, the engine, the power-train and the catalytic converter is illustrated. The proposed control is obtained by: 1) decoupling the control problem into two sub-problems; and 2) relaxing each of the two subproblems to yield problems that can be solved with classical control techniques. The control law so obtained is mapped back into the hybrid domain. The quality of the proposed hybrid control feedback is demonstrated analytically and by simulations on the full-fledged hybrid model.