| 摘要 |
PROBLEM TO BE SOLVED: To prevent an improperly discharged fuel quantity at a specific operation point from a low pressure pump from reaching a high pressure region with high efficiency and durability based on a simple and sturdy method by providing a fuel return conduit in a fuel pump unit. SOLUTION: In a fuel pump unit 1 provided with a low pressure region ND having a low pressure pump 2 and a high pressure region HD having a quantity controlled high pressure pump 3 such that the high pressure pump 3 discharges the necessary fuel quantity to correct the quantity balance in the high pressure region, and wherein the quantity control is performed via a distributor 5 located between the low pressure pump 2 and the high pressure pump 3, the discharge flow of the low pressure pump 2 is larger than the discharge flow of the high pressure pump 3. A fuel return conduit 8 which opens to an inlet of the low pressure pump 2 branches between the distributor 5 and the high pressure pump 3. Also, a control element 9 is arranged in this fuel return conduit 8. |
