Patent ID: 9556841
Date: 2017-01-31
CPC Classifications: F02M

Claim:
1. A fuel supply system for an internal combustion engine, comprising: a fuel pump configured to pump fuel from within a fuel tank and discharge the pumped fuel to the internal combustion engine; a motor configured to drive the fuel pump; and a controller coupled to the motor and configured to determine a duty ratio of a control signal through a feedback control and to output the control signal to the motor, so that a fuel pressure of the fuel discharged from the fuel pump approaches a target fuel pressure; wherein the controller is further configured to (i) estimate the duty ratio based on the target fuel pressure and information regarding the fuel pressure of the fuel discharged from the fuel pump, and (ii) guard an upper limit of the duty ratio by an upper limit guard value; and wherein the controller is further configured to change the upper limit guard value based on a rotational speed of the motor.