HIGH PRESSURE PUMP

摘要

The invention relates to a high pressure pump for a common rail pump system and to a common rail pump system. A high pressure pump (2) for a common rail pump system comprises a pump body (4) having a cylinder (6) with a piston bore (8) and a piston (10) reciprocally driven in the piston bore (8) by an eccentric to pressurize fuel in the cylinder (6). The piston (10) comprises an inner end (12) located in the piston bore (8) and an outer end (14) outside the piston bore (8). A bellow (20) having a first opening (22) and a second opening (24) is arranged between the piston (10) and the pump body (4), wherein the piston (10) extends through the first opening (22) and the second opening (24), wherein the bellow (20) is connected to the pump body (40) such that the first opening (22) is sealed on the pump body (4, 50) and wherein the bellow (20) is connected to the outer end (14) of the piston (10) such that the second opening (24) is sealed on the piston (10). This prevents mixing of engine oil and fuel, when the pump is directly attached to an engine. The bellow may be connected to a drainage line over a one-way valve.