END BIT (R.H. - 1.625" Thick) 7J3457 - Caterpillar

Fuel Transfer Pump
Illustration 4 g06301265
(1) Fuel Transfer Pump
(2) High-Pressure Fuel Pump
Illustration 5 g06083244
(3) Fuel Transfer Pump Pressure Relief Valve
(4) Shaft Seal
(5) Weep Hole (Do Not Obstruct)The fuel transfer pump (1) is a fixed displacement gear pump that is driven by the high-pressure pump. The fuel transfer pump receives fuel from the primary fuel filtration unit. The pump sends the fuel through the secondary filters on the way to the high-pressure fuel pump. The fuel transfer pump also supplies cooling flow to the injectors, and the high-pressure pump.The fuel transfer pump is mounted on the high-pressure pump (2). A relief valve (3) in the fuel transfer pump limits the outlet pressure to 950 kPa (138 psi). Other important parts include the shaft seal (4) and the weep hole (5) which prevent fuel in oil contamination.High-Pressure Fuel System
Illustration 6 g06301284
(1) Injector
(2) Accumulator-Quill Tube
(3) Line Support Clamps
(4) High-Pressure Injection Lines
(5) Pump to Accumulator High-Pressure Lines
(6) High-Pressure junction Block
(7) High-Pressure Fuel PumpThe common rail high pressure fuel system on this engine consists of high-pressure fuel accumulator-quill tubes (2) that maintain a volume of fuel that is used to supply each cylinder as needed and high-pressure fuel lines (4) to transport fuel between the high-pressure fuel pump (7), high-pressure accumulator quill tubes (2), and the common-rail injectors (1).The main components of this system Illustration 6 are between the high-pressure fuel pump (7) and the injectors (1):
High-Pressure Fuel Pump to Junction Block Lines
High-Pressure Junction Block
Accumulator Quill Tubes
Accumulator Quill to Accumulator Quill Fuel Injection LinesThe low-pressure fuel system provides fuel at the proper pressure, temperature, and cleanliness level to the high-pressure fuel pump. The high-pressure fuel pump pressurizes the fuel to the level required for the engine operating condition. System pressure in the high-pressure fuel system is controlled electronically via a fuel control valve, which regulates the amount of fuel that is allowed to enter the inlet of the pump. A pressure relief valve mounted on the high-pressure pump manifold mechanically limits the maximum fuel pressure in the system in the event of a malfunction.High-Pressure fuel flows from a manifold on the high-pressure pump (7) to a high-pressure junction block (6), which distributes fuel to each engine cylinder bank via double-walled high-pressures lines (4). The double-wall serves to prevent the escape of any high-pressure fuel in the event of fuel leakage from the high-pressure system and therefore ensures safe containment of the fuel in the event of a high-pressure leak. The fuel is then transported through the high-pressure lines (4), through the accumulator quill tubes (2), and to the injectors (1). If leakage into the double-wall system occurs, the necessary repairs need to be performed as quickly as possible to prevent further damage to the high-pressure fuel system.Fuel is transported to the modular accumulator-quill tubes via the double-walled injector lines. The modular accumulators contain an integral metallic filter to prevent debris from getting to the injectors as well as an integral flow limiting device that shuts off flow to the cylinder and prevents over fueling in the event