Fuel System - Operation and Tests/In-line Injection Pump FUEL TRANSFER PUMP OPERATION (IN-LINE INJECTION PUMP) The plunger-type MICO fuel supply pump is mounted on the side of the injection pump housing and is driven by the injection pump camshaft. Fuel enters the supply pump at (A), is pressurized by the plunger (B) to 350 kPa (3.5 bar; 50 psi), and discharged through outlet (C). The hand primer (D) provides manual pump operation for bleeding the fuel system.
CD30740 -UN-23FEB99 A—Fuel inlet B—Plunger C—Fuel outlet D—Hand primer CD,3274,G220,21-19-04JAN99 CTM3274 (01JUL99) 220-17 Saran Liter Engines 060799 PN=356 FUEL SYSTEM OPERATION—IN-LINE INJECTION PUMP The supply pump (F) draws fuel from the vented fuel The high pressure fuel (K) opens the nozzle valve tank through the primary filter (B) when equipped. and forces fuel out the small orifices in the nozzle tip. This atomizes the fuel as it enters the combustion The supply pump pressurizes the fuel so that it flows chamber. through the filter (A) to the injection pump galley.
Supply pump output pressure will vary depending on There are two sources of excess fuel incorporated load and application. into the system. The supply pump supplies more fuel to the pump than is required by the engine, and the The galley is kept full by the supply pump. Injection nozzle requires excess fuel to lubricate the nozzle pump plungers further pressurize the fuel. Injection valve. A leak-off line (L) returns this excess fuel to pressure lines route the fuel to the nozzles (C). the tank from both the pump and nozzles. CD,3274,G220,20-19-04JAN99 220 17