We address the problem of delivering as quickly as possible a requested tor
que produced by a spark ignition engine equipped with a multi-point port in
jection manifold and with electronic throttle. The optimal control problem,
subject to the constraint that the air-fuel ratio stays within a pre-assig
ned range around the stoichiometric ratio, is solved for a detailed, cycle-
accurate hybrid model with a hybrid control approach based on a two-step pr
ocess. In the first step, a continuous approximation of the hybrid problem
is solved exactly. Then, the control law so obtained is adjusted to satisfy
the constraints imposed by the hybrid model. The quality of the control la
w has been in part analytically demonstrated and in part validated with sim
ulations. Copyright (C) 2001 John Wiley & Sons, Ltd.