PANEL AS-SWITCH 4507174 - Caterpillar

Illustration 1 g03347416
Fuel system components (1) Fuel injectors (left side) (2) Fuel rail pressure sensor (3) Return line for injector bypass fuel (4) High-pressure fuel pump (5) Fuel control valve and controller (6) Filter for high-pressure fuel (edge filter) (7) Fuel Priming Pump (8) Fuel injectors (right side) (9) Temperature sensor for the low-pressure fuel (10) Unfiltered fuel pressure sensor (11) Filtered fuel pressure sensor (12) Test port for outer wall leakage collection (13) Temperature sensor for the high-pressure fuelThe fuel system for this engine incorporates a low-pressure fuel system and a high-pressure fuel system into the engine design.The low-pressure fuel system is used to transfer fuel from the fuel tank to the high-pressure fuel pump. During the transfer of fuel, water is removed from the fuel. Also, the fuel is filtered. The system incorporates a mechanical fuel transfer pump that is used to transfer fuel during engine operation. An electric fuel priming pump is used as a booster pump to increase fuel pressure in the system during engine starting. The fuel priming pump is also used to prime the low-pressure fuel system after the fuel filters are changed.The high-pressure fuel system pressurizes the fuel prior to injection. The fuel is transferred to the injectors through double wall fuel lines. The fuel injectors are used to produce atomized fuel during the fuel injection cycle. Flow limiters are used to limit the total flow of fuel to the injector to a preset level. Also, if an injector tip fails, the flow limiters will prevent the cylinder from filling with fuel. The fuel system is made up of the following components:
Low-pressure fuel lines
Primary fuel filter/water separator
Advanced efficiency secondary fuel filter
Mechanically driven fuel transfer pump
Electric fuel priming pump
High-pressure fuel pump and fuel control valve
In-line high-pressure fuel filter
Double wall fuel lines
High-pressure fuel injectors
Electronic control system componentsThese fuel system components form the design of these three engine subsystems:
Low-pressure fuel system
High-pressure fuel system
Electronic control system for fuel deliveryLow Pressure Fuel System
Illustration 2 g02476123
Schematic of the low-pressure fuel system (typical configuration) (16) Secondary fuel filters (17) Tertiary filter (18) High-pressure fuel system (19) Pressure regulator (low-pressure fuel) (20) Electric fuel priming pump (21) Vent cap for the fuel tank (22) Check valve (high-pressure fuel) (23) Check valve (outer wall leakage) (24) Mechanical fuel transfer pump (25) primary filter/water separator (26) Fuel tankThe fuel is drawn from fuel tank (26) to the primary filter/water separator (25). The fuel tank uses vent cap (21) to vent off excess pressure for the fuel tank. The fuel is drawn into mechanical fuel transfer pump (24) and electric fuel priming pump (20). The electric fuel priming pump is energized during engine starting. Also, the electric priming pump can be used for priming the fuel system. The low-pressure pumps must pressurize the fuel to approximately 250 kPa (36 psi) in order to open the check valve in the high-pressure fuel pump during engine starting. The mechanical fuel transfer pump pressurizes the low-pressure fuel system to a gauge pressure of 725 to 795 kPa