US Patent 7778767 Cold start emission strategy for hybrid vehicles

An engine control module includes an engine starting module that communicates with an electric motor to operate an internal combustion engine including M fuel injectors and that determines whether manifold pressure is below a manifold pressure threshold. A warming module communicates with the M fuel injectors to inject fuel into N of M the fuel injectors when the manifold pressure is less than the manifold pressure threshold. N and M are integers and N is less than M.