Patent ID: 7720592

Claim:
A vehicle system comprising: a fuel system containing a first type of fuel and a second type of fuel at least one cylinder; a port injection fuel injector to inject fuel into an intake passage in operative communication with the at least one cylinder, the port injection fuel injector being supplied with a first type of fuel from the fuel system; a direct injection fuel injector to inject fuel directly into the at least one cylinder, the direct injection fuel injector being selectively supplied with at least one of the first type of fuel and the second type of fuel from the fuel system; an emissions control device positioned to receive emissions exhausted from the at least one cylinder; and a control system configured to cause the first type of fuel from the fuel system to be supplied to the direct injection fuel injector in response to an engine start condition, to cause the second type of fuel to be supplied from the fuel system to the direct injection fuel injector based on a temperature of the emissions control device exceeding a threshold temperature, and to cause the second type of fuel to be supplied from the fuel system to the direct injection fuel injector based on an increased in engine output even when the temperature is below the threshold temperature.