Systems and method for controlling auto-ignition

A method, comprising:

• injecting a first fuel to a combustion chamber via a direct injector positioned to inject directly into the combustion chamber;
• flowing a different, second fuel to the combustion chamber via a valve positioned to inject toward an intake port of the combustion chamber;
• determining a first auto-ignition exceeds a threshold level;
• in response determining the first auto-ignition exceeds the threshold level:
• adjusting a substitution rate of the first fuel and the second fuel;
• and
• retarding an injection timing of the injection of the first fuel;
• determining a second auto-ignition is equal to or less than the threshold level;
• and
• in response to determining the second auto-ignition is equal to or less than the threshold level:
• retarding a first fuel injection timing while maintaining the substitution rate;
• and
• incrementally reducing the substitution rate in response to auto-ignition occurring following retarding the first fuel injection timing.

A system, comprising:

• an engine of a vehicle comprising a plurality of cylinders;
• a first fuel system fluidly coupled to direct injectors of the plurality of cylinders and configured to supply a first fuel by injecting the first fuel;
• a second fuel system fluidly coupled to intake port injectors and configured to supply a second fuel different than the first fuel;
• a third fuel system fluidly coupled to one of the direct injectors or the intake port injectors and configured to supply a pre-mixture of the first and second fuels;
• and
• a controller with instructions stored on non-transitory memory that cause the controller to:
• in response to a comparison of an auto-ignition to a threshold level determining the auto-ignition being greater than the threshold level:
• adjusting a substitution rate of the first fuel and the second fuel;
• and
• retarding an injection timing of injection of the first fuel;
• and
• in response to the comparison of the auto-ignition to the threshold level determining the auto-ignition to be equal to or less than the threshold level:
• retarding a first fuel injection timing while maintaining the substitution rate in response to determining the auto-ignition level is less than or equal to the threshold level.