| 摘要 |
PROBLEM TO BE SOLVED: To reduce pulsation produced at the feed side fuel piping by installing a check valve, which passes fuel only in one direction to a low pressure pump from a high pressure fuel pump, in a bypass installed in a feed side fuel passage between both high and low pressure pumps. SOLUTION: During the suction of fuel in a high pressure fuel pump 3, since a check valve 10 of a bypass 9 is closed, the fuel is drawn into the high pressure fuel pump 3 by way of a feed side fuel passage 5 alone. Then suction of fuel in the high pressure fuel pump 3 is terminated and the moment an inlet valve is closed, high pressure generated by the inetia of fuel in the feed side fuel passage 5 is conversely turned to a pressure wave and it is starting to propagate to an upstream side from the high pressure furl pump 3. When this propagation has reached to check valve 10 of the bypass passage 9, this check valve 10 is opened, and pressure goes past to the side of a low pressure fuel pump 6 through the check valve 10, whereby the peak height of surge pressure is lowered. If the high pressure furl pump 3 restarts its inlet motion, the check valve 10 is closed, returning to the original state. |
