Patent ID: 6899085

Claim:
A common rail fuel injection system for a motor vehicle, comprising: a distributor rail 16 fluidly connected to at least one fuel injector 18 ; an accumulator chamber 14 fluidly connected to the distributor rail, for supplying high pressure fuel to the distributor rail; a high pressure fuel pump 10 that has an inlet for receiving fuel from a low pressure feed system 20 , 22 , 24 and an outlet chamber 12 for proving fuel at high pressure to the accumulator 14 ; a recirculation valve 52 fluidly connected to the pump outlet chamber 12 , the accumulator 14 , and the low pressure feed system, wherein at a first position the recirculation valve fluidly aligns the outlet chamber 12 with the accumulator 14 for delivery of high pressure fuel to the accumulator and in a second position aligns the outlet chamber with the low pressure system for recirculation of fuel through the high pressure pump substantially at the pressure in the low pressure system; and a switching valve 50 fluidly connected to the pump outlet chamber 12 , the accumulator 14 , and said recirculation valve 52 , wherein at a first position the switching valve 50 actuates said recirculation valve 52 to said first position and at a second position the switching valve 50 actuates said recirculation valve 52 to said second position; said switching valve 50 including means 62 for establishing a set point pressure whereby when the pressure in the accumulator 14 is below the set point, the switching valve 50 actuates the recirculation valve 52 to said first position and when the pressure in the accumulator 14 reaches the set point, the switching valve 50 actuates the recirculation valve 52 to said second position.