Warm up strategy for ethanol direct injection plus gasoline port fuel injection

A method for controlling an engine, the engine having a cylinder with a first fuel injector configured to inject a first substance to the cylinder, and a second injector configured to inject a second substance to the cylinder, the method comprising:

• commencing combustion in the engine by injecting fuel into said cylinder, where said fuel is injected by only one of said first and second injectors during said start;
• and
• enabling injection from an other of said first and second injectors in response to an operating condition;
• wherein said first injector is a port injector and said second injector is a direct cylinder injector, where only said port injector supplies fuel at least during a portion of said start, and wherein said first substance includes gasoline and said second substance includes ethanol.

A system for an engine, comprising:

• a cylinder of the engine;
• a first direct injector configured to inject a first substance to said cylinder;
• a second port injector configured to inject a fuel to said cylinder;
• and
• a controller configured to perform combustion in the engine by injecting fuel into said cylinder, where said fuel is injected by said port injector during selected engine starting conditions, and injection by the direct injector is enabled based on an operating condition;
• wherein said operating condition is temperature, and wherein said first substance includes ethanol.

A system for an engine, comprising:

• a cylinder of the engine;
• an injector configured to inject a mixture of gasoline and an alcohol to said cylinder;
• and
• a controller configured to vary a relative amount of said gasoline and alcohol to increase an amount of gasoline combusted in the engine relative to said alcohol during engine starting;
• and
• after said engine starting, said controller is further configured to increase an amount of the alcohol combusted in the engine relative to said gasoline as engine load increases.