Driveability - Diesel - Non-Dtc Based Diagnostics: Overview Jeep Compass I рестайлинг

Theory of Operation

There are two sides to the 2.2L fuel system. A low pressure and high pressure side. The low pressure side components are the Fuel Lift Pump; the Fuel Filter; Cascade Valve; and the Fuel Quantity Solenoid. The Fuel Lift Pump, mounted inside the tank, delivers the fuel from the tank to the High Pressure Delivery Pump (HPDP). The Fuel Filter, mounted at the bulk head on the drivers side, removes water and debris from the fuel and helps to prevent damage to the HPDP and Fuel Injectors. The Cascade Valve, located inside the HPDP, regulates the low side pressure at approximately 3.8 bar (55 psi). The Fuel Quantity Solenoid, mounted to the HPDP, controls the quantity of fuel entering the HPDP internal pumping chambers. Excess fuel is returned back to the tank via a return line from the HPDP. The high pressure side components include the High Pressure Delivery Pump; the Fuel Rail; the Fuel Injectors; and the Fuel Pressure Regulator. The HPDP raises the fuel pressure entering the Fuel Rail using two internal pumping chambers. The Fuel Rail holds the high pressure fuel for use by the Fuel Injectors and helps to dampen pressure spikes caused by the HPDP and the opening and closing of the injectors. The solenoid actuated Fuel Injectors deliver high pressure fuel directly into the engine cylinders. During injector operation, a small amount of fuel leaks into the injector return hoses. The injector return hoses connect to the HPDP. A venturi inside the HPDP draws the return flow into the HPDP where it is directed back to the tank via the HPDP return line. The Fuel Pressure Regulator (FPR) works in tandem with the Fuel Quantity Solenoid (FQS) to control the fuel pressure in the fuel rail. During engine cranking, the FQS allows maximum fuel flow and the FPR is closed to allow pressure to build quickly. After the engine starts, the FPR is primarily closed and the high side pressure is regulated using the FQS. The FPR is primarily used to help control spikes in the high pressure side during deceleration or if the FQS is not able to react quickly enough to the demands of the system.

See also:
• Standard Procedure