Engine boost control for multi-fuel engine

A method of operating an internal combustion engine having a first and second fuel storage tank, comprising:

• selectively transferring at least some fuel from the first tank to the second tank so that the first tank is emptied before the second tank;
• delivering fuel from the second fuel tank to a direct fuel injector of the engine;
• and
• adjusting a level of intake air boost in response to an alcohol concentration in the fuel delivered to the engine from the second tank.

A method of operating an internal combustion engine, comprising:

• delivering a first fuel to the engine from a first fuel storage tank;
• delivering a fuel mixture to the engine from a second fuel storage tank, said fuel mixture including at least the first fuel and a second fuel;
• transferring at least a portion of the first fuel from the first fuel storage tank to the second fuel storage tank in response to a concentration of alcohol contained in the fuel mixture;
• and
• adjusting a level of boost provided to the engine in response to a concentration of the second fuel in the fuel mixture.

An engine system, comprising:

• an internal combustion engine including at least a combustion cylinder and an intake air passage communicating with the cylinder;
• a boosting device arranged along the intake air passage;
• a first fuel storage tank fluidly coupled with at least a first fuel injector configured to deliver fuel from the first fuel storage tank to the combustion cylinder;
• a second fuel storage tank fluidly coupled with at least a second fuel injector configured to deliver fuel from the second fuel storage tank to the combustion cylinder;
• a fuel transfer passage fluidly coupling the first fuel storage tank and the second fuel storage tank;
• and
• a control system configured to:
• transfer fuel from the first fuel storage tank to the second fuel storage tank via the fuel transfer passage to maintain at least a threshold amount of fuel in the second fuel storage tank;
• supply fuel to the combustion cylinder from the first fuel storage tank via the first fuel injector and from the second fuel storage tank via the second fuel injector;
• and
• adjust a level of boost provided to the engine via the boosting device in response to a concentration of alcohol in the fuel supplied to the engine from the second fuel storage tank via the second fuel injector.