Patent ID: 9593651
Date: 2017-03-14
CPC Classifications: F02D,F02M

Claim:
1. A fuel-filter malfunction detection device applied to a fuel supply system which is provided with a high-pressure pump pressurizing a fuel which will be supplied to a fuel injector of an internal combustion engine, a fuel filter arranged upstream of the high-pressure pump for removing a foreign matter from the fuel, a common-rail accumulating the fuel pressurized by the high-pressure pump for supplying the fuel to the fuel injector, and a pressure sensor arranged downstream of the high-pressure pump for detecting a pressure of the fuel which will be supplied to the fuel injector, the fuel-filter malfunction detection condition device comprising: a discharge control portion increasing or decreasing a discharge quantity of the high-pressure pump when a specified malfunction detection condition is established; a pressure obtaining portion obtaining a fuel pressure which the pressure sensor detects; a malfunction determination portion determining whether the fuel filter has a malfunction based on the fuel pressure obtained by the pressure obtaining portion, when the discharge control portion increases or decreases the discharge quantity of the high-pressure pump with a specified malfunction detection condition established; a pressure decreasing portion decreasing the pressure in the common-rail after the pressure obtaining portion obtains the fuel pressure from the pressure sensor; and a pressure-reducing valve decreasing a fuel pressure in the common-rail, wherein the discharge control portion increases the discharge quantity of the high-pressure pump when the specified malfunction detection condition is established, when a pressure differential pressure between an estimated fuel pressure and an actual fuel pressure is greater than or equal to a specified pressure in a case that the discharge control portion increases the discharge quantity of the high-pressure pump, the malfunction determination portion determines that the fuel filter has a malfunction, the pressure decreasing portion closes the pressure-reducing valve when the discharge control means increases the discharge amount of the high-pressure pump when the specified malfunction detection condition is established, and, the pressure decreasing portions opens the pressure-reducing valve to decrease the fuel pressure in the common-rail when the pressure obtaining means obtains the fuel pressure.