New Holland 667TA/EBF, Repair Manual

Page: 59 / 150

2-41
87519804 NA Issued 11-06 Bur
CHAPTER 2 - 667TA ENGINE OVERHAUL
ENGINE REPAIR MANUAL
FUEL SUPPLY SYSTEM DIAGRAM
BS06K055
Figure 2-50
The supply pressure regulator controls the flow of
fuel needed in the low pressure system. The high
pressure pump supplies the common rail. This
pressurization of fuel, improves energy efficiency and
limits the heating of the fuel in the system.
The low pressure regulator valve (2) installed on the
high pressure pump maintains the pressure at a
constant level of 5 bars (72 psi.).
Low pressure regulator valve (2) operates to
increase fuel flow in the high pressure pump cooling
circuit through line (16) carrying fluid into and out of
line (8).
The common rail safety relief valve (3) installed in the
cylinder head. Controls the flow of fuel returning from
the electro-injectors at a pressure of 1.3 to 2 bars (19
to 29 psi.).
In parallel with the mechanical supply pump there are
two by-pass valves.
Rotor pump pressure safety by-pass valve (18)
makes it possible to have the fuel flow back from the
mechanical pump outlet to its inlet, when the
p r e s s u r e a t t h e f u e l f i l t e r i n l e t ex c e e d s t h e
permissible limit. The rotor pump by-pass valve (17)
makes it possible to fill the supply system via the
manual priming pump (10).
1. HIGH PRESSURE PUMP 9. EDC7UC31 CONTROL UNIT HEAT EXCHANGER
17. MECHANICAL ROTOR PUMP
BY-PASS CHECK VALVE
2. LOW PRESSURE REGULATOR VALVE
ON HIGH PRESSURE PUMP
10. MANUAL PRIMING PUMP
18. ROTOR PUMP PRESSURE
SAFETY BY-PASS
3. COMMON RAIL SAFETY RELIEF VALVE 11. PRE-FILTER A. DRAIN
4. BACK PRESSURE VALVE IN FUEL
RETURN LINE FROM INJECTOR
12. FUEL TANK B. SUCTION
5. COMMON RAIL 13. GEAR CHARGE FEED PUMP C. LOW PRESSURE
6. RAIL PRESSURE SENSOR 14. FUEL FILTER D. HIGH PRESSURE
7. ELECTRO-INJECTOR 15. HIGH PRESSURE PUMP BY-PASS CHECK VALVE
8. HIGH PRESSURE PUMP AND INJECTOR
RETURN LINE
16. RETURN LINE FROM HIGH PRESSURE PUMP
5
4
3
1
11
9
2
7
18
17
10
6
8
12
14
13
15
D
C
B
A
16