Specification Of Supply Pump; Injection Pipe; Outline Of Injection Pipe; Structure Of Injection Pipe - Kubota D1803-CR-E4 Workshop Manual

MECHANISM
3. Fuel system
Zero delivery drain
(17) Zero delivery drain
The zero delivery drain (17) has a function of
preventing fuel flow to the pressurizing part when no
fuel is being delivered.
Though the suction control valve is set to no flow, a
small amount of fuel flows to the pressurizing part.
The zero delivery drain is provided to prevent this and
this small amount of fuel is returned through the zero
delivery drain and returned to the fuel tank.
Note, other than no delivery, fuel is delivered to the
pressurizing part based on the amount of throttle and
very little flows to the zero delivery drain.
Overflow valve
(18) Ball
(19) Valve body
(20) Spring
(21) Port
When the pressure of fuel delivered from the feed
pump rises above a prescribed amount, the overflow
valve has a function of returning fuel to the tank.
When fuel pressure increases and exceeds the force of
the spring, the valve piston is pushed.
Here, the fuel passes through the port (21) provided in
the valve body and returns to the fuel tank.
Therefore, the pressure in the suction control valve is
stabilized and fuel flow is accurately adjusted.
D1803-CR-E4,D1803-CR-TE4,D1803-CR-TIE4,V2403-CR-E4,V2403-CR-TE4,V2403-CR-TE4BG,V2403-CR-TIE4
(22) Valve piston
[G] While closed
[H] While opened

3.10.4 Specification of supply pump

Pump type
Rail pressure reference values
Engine model
At idling
D1803-CR-E4
D1803-CR-TE4
D1803-CR-TIE4
25 to 30 MPa
260 to 300 kgf/cm
3700 to 4300 psi
V2403-CR-E4
V2403-CR-TE4
V2403-CR-TIE4
V2403-CR-TE4BG

3.11 Injection pipe

3.11.1 Outline of injection pipe

Injection pipes connect the supply pump and rail as
well as the rail and injectors.

3.11.2 Structure of injection pipe

The injection pipes between the rail and injectors are
designed with equal length.
(1) Injection pipe
4. ENGINE
Bosch PF49
At rated speed (No
load)
55 to 60 MPa
2
560 to 610 kgf/cm
8000 to 8700 psi
75 to 80 MPa
2
765 to 815 kgf/cm
10900 to 11600 psi
100 to 110 MPa
1020 to
2
1120 kgf/cm
14500 to 15900 psi
2
60 to 65 MPa
2
620 to 660 kgf/cm
8700 to 9400 psi
95 to 115 MPa
2
970 to 1170 kgf/cm
14000 to 16600 psi
70 to 75 MPa
2
720 to 760 kgf/cm
10200 to 10800 psi
4-23
KiSC issued 12, 2018 A