140-3 SERIES
11-59
STRUCTURE AND FUNCTION, MAINTENANCE STANDARD OUTLINE OF CRI SYSTEM
STRUCTURE AND FUNCTION OF COMPONENTS
1. Fuel supply pump
1) Outline
The fuel supply pump consists of the priming pump, feed pump, and high-pressure pump. Its function gener-
ates the fuel pressure inside the common rail by the control of the fuel discharge amount.
2) Structure
With the high-pressure pump, pump control valves (discharge amount control valves) are installed to each cylin-
der to control the force feed system and fuel discharge amount in the same way as the conventional in-line fuel
injection pump.
By employing cams with 3 protrusions, the necessary number of high-pressure pumps (cylinders) is reduced to
1/3 of the number of engine cylinders. In addition, the force feed to the common rail is the same number of
times as the number of times of fuel injection, so it is possible to obtain a smooth and stable common rail pres-
sure.
The fuel force fed from the high-pressure pump to the common rail is divided as follows for each pump.
The No. 1 high-pressure pump (drive gear side) (4) covers the drop in the pressure inside the common rail
because of the fuel injection of the No. 1, No. 3, and No.5 cylinders, while the No. 2 high-pressure pump (feed
pump side) (6) covers the drop in the pressure inside the No.2, No.4 and No.6 cylinders of common rail in the
same way.
1.
3-protrusion type cam
6.
No.2 high-pressure pump
2.
Overflow valve
7.
Priming pump
3.
Drive gear
8.
Feed pump
4.
No.1 high-pressure pump
9.
G revolution sensor gear
5.
PCV (discharge control valve)
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