TM2361 (24JUN08) 9010-05-5 450DLC Excavator Operation and Tests 062608 PN=253 Theory of Operation 1—High Pressure Common 3—Electronic Injector (6 used) 5—Fuel Tank 7—Fuel Transfer Pump Rail 4—Pressure Control Valve (2 6—Water Separator 8—High Pressure Fuel Pump 2—Fuel Filter (primary and used) secondary) Fuel Supply System Operation The ECM controls injection amount based on both actual engine speed and target engine speed. The The fuel transfer pump (7), driven by high pressure ECM receives actual engine speed information from fuel pump drive shaft, draws fuel from the fuel tank (5) the crankshaft position sensor and camshaft position through a water separator (6).
The water separator sensor. The main controller (MCF) supplies target removes water particles from the fuel. When the water engine speed information to the ECM based on the level, which can be seen through the clear plastic engine speed dial, pressure sensors, and power mode body, reaches the warning line, the water separator switches. must be drained. A self-venting drain plug is mounted on the bottom of the clear plastic sediment bowl. The ECM calculates fuel injection timing according to engine speed and fuel injection amount.
After water is removed, the fuel is delivered to the primary and secondary fuel filters (2) for removal of Injection pressure is controlled through the fuel any solid particles that might cause abrasive damage pressure in the high pressure common rail. The ECM to the injection system. After filtering, clean calculates the appropriate pressure in the high pressurized fuel is delivered to the high pressure fuel pressure common rail based on engine speed, fuel pump (8). An independent priming pump permits injection amount, and common rail pressure. Using the manual fuel feed for maintenance activities when timing of the PCVs opening and closing, the ECM can engine is not running.
regulate the fuel pressure in the high pressure common rail. Fuel Injection System Operation The fuel injection system uses an injection rate that The high pressure fuel pump raises the pressure of the helps improve combustion in the cylinders. A small fuel to the required pressure for injection in two amount of fuel is injected first into the cylinder. After pumping chambers. When there is no current to the this pilot injection ignites, the main supply of fuel is pump control valves (PCVs) (4), fuel is allowed to fill injected. the pumping chamber. The engine control module (ECM) sends a signal to the PCVs to shut the valve to Fuel Injection Nozzle Operation the pumping chamber.
When the fuel pressure exceeds the delivery valve opening pressure, the high The electronic injectors are located inside the engine’s pressure fuel is routed to the high pressure common cylinder head and are electrically controlled by the rail (1). The high pressure common rail evenly ECM. High pressure fuel is constantly supplied to the distributes fuel to all of the electronic injectors (3). If electronic injectors by the high pressure common rail.
excess fuel pressure develops in the high pressure The opening and closing of the two-way valve within common rail, a pressure limiter opens and routes the each injector by the ECM controls the injection fuel through a fuel return line back to the fuel tank. amount, the injection timing, and the injection rate for Excess fuel in the high pressure fuel pump is routed each electronic injector. back to the fuel tank through a fuel return line. The ECM controls the injection amount, the injection timing, injection pressure, and the injection rate for each injector. Continued on next page JC89288,0000037 –19–30JAN06–2/5 9010 05 5