System and method for operating a direct injection fuel pump

摘要

Methods and systems are provided for a direct injection fuel pump. The methods and systems selectively operate the direct injection fuel pump with varying levels of efficiency. In one example, an amount of piston lift of a direct fuel injection pump may be adjusted to selectively alter the pump's operating efficiency.

主权项

1. A method of operating a direct injection fuel pump, comprising:
in response to engine knock,
during a first condition where the first condition is a first engine load, operating the direct injection fuel pump with a first piston lift amount;during a second condition where the second condition is a second engine load greater than the first engine load, the second condition different from the first condition, operating the direct injection fuel pump with a second piston lift amount, the second piston lift amount greater than the first lift amount; in the absence of engine knock, deactivating the direct injection fuel pump; and activating the direct injection fuel pump from a deactivated state via engaging a low lift cam profile in response to fuel pressure less than a threshold in a fuel rail supplied fuel by the direct injection fuel pump while direct fuel injectors coupled to the fuel rail are deactivated in response to the absence of engine knock.