A great deal of work has been done in recent years to measure or to pr
edict the real-time emissions from motor vehicles. This is necessary n
ot only to control and to reduce the emissions but also to calculate t
he real emission load resulting from motor vehicles. Global measuremen
ts made on representative driving cycles or calculations made with glo
bal emission factors do not reflect the real emission characteristics
of vehicles on the road. in this paper, a theoretical approach is demo
nstrated for the calculation of the CO emissions of a vehicle powered
by a gasoline engine. The calculation model is based on the air excess
ratio (lambda) records of the engine while following a driving cycle.
Other engine parameters, such as engine speed, ignition time advance,
throttle valve position, intake air and coolant temperatures, fuel an
d air flow-rates, are also recorded to feed the thermodynamic cycle an
d CO emission calculation models. The calculated and the measured tota
l CO emissions at the end of the driving cycle are approximately at th
e same level, although instantaneous emissions are not coincident quan
titatively well on the time axis.