A method of controlling fuel supplied to an engine of a vehicle is
provided. The vehicle includes a first fuel storage tank to store a first
type of fuel, a second fuel storage tank to store a second type of fuel,
and an emissions control device. The engine includes at least one
cylinder having a direct injection fuel injector being selectively
supplied with the first type of fuel from the first fuel storage tank and
the second type of fuel from the second fuel storage tank. The method
includes supplying the first type of fuel from the first fuel storage
tank to the direct injection fuel injector in response an engine start
condition of the vehicle, and supplying the second type of fuel from the
second fuel storage tank to the direct injection fuel injector, in
response to an increase in engine output exceeding a threshold increase
or a temperature of the emissions control device exceeding a threshold
temperature.