0010 - Function of the injection system P. Injection nozzles (note deviations for off-road vehicles) Engines 601, 602.91, 603.91

07.1-010 Function injection system

P. Injection nozzles

a) Facet-type pintle nozzle

Bosch designation DN 0 SD 261 and 265
This nozzle differs from the pintle nozzle by a flat (arrow) on the throttling pintle (41). This causes an improved throttling effect.

31 Nozzle needle

32 Nozzle body

41 Throttling pintle

44 Injection pintle

b) Hole-type pintle nozzle

Bosch designation DN 0 SD 240/
This nozzle is distinguished from the pintle nozzle by transverse and longitudinal bores (46 and 47) in the throttling pintle.

31 Nozzle needle

32 Nozzle body

46 Transverse bore

47 Longitudinal bore

c) Nozzle holder

Bosch designation
KCA 30 S 44 (without edge-type filter)
(vertical injection)
KCA 30 S 46 (with edge-type filter)
(vertical injection)
KCA 27 S 55
(inclined injection)

Since October 1992 Lucas nozzle holders may be installed alternatively in place of the Bosch nozzle holders.

Production breakpoint: October 1992

The compression spring (36) in the holding body (37) presses on the nozzle needle (31) via thrust pin (34). The preload of the compression spring (36) and the shim (40) determine the opening pressure of the injection nozzle. The injection pressure can be adjusted by means of different shim thickness dimensions. Fuel flows to the nozzle seat via the respective supply bore (a) in the holding body (37), intermediate washer (33) and injection nozzle. During the injection process the injection pressure lifts the nozzle needle and the fuel flows through the circular groove on the throttling pintle into the prechamber.

After the injection pressure has dropped, the compression spring (36) forces the nozzle needle (31) back onto its seat; the injection process is completed.

Nozzle holder for vertical injection

d) Inclined injection

5° inclined injection
Engine 601.911/912 with code 620 as of 09/86
Engine 602  model year 1987 and 1988
Engine 601 and 603  model year 1988

The nozzle holder combination is screwed into the prechamber upper part with an inclination of 5° with reference to the prechamber longitudinal axis. The inclined injection results in an even more intensive mixing of air with fuel.

70 Cylinder head

71 Cylinder head gasket

109 Sealing sleeve

110 Prechamber

112 Threaded ring

113 Sealing plate

114 Nozzle holder

Engine 601.911/912   and code 830 and

960 as of model year 1989
Engine 602     and code 830 as

of model year 1989
Engine 603    and code 830 as of

model year 1989
Engine 601.913 as of 06/1993

The nozzle holder combination inclined by 5° is twisted by 180° and installed in the prechamber upper part.

This has the following advantages:

 Improved cold starting

 Improved mixing of air and fuel due to shortened glow plug (23 mm previously
27 mm) in connection with recess and spherical indentation in the ball pin.

 Particle reduction and improvement of hydrocarbons and carbon monoxide.

R9 Glow plug
109 Sealing sleeve
110 Prechamber
112 Threaded ring
113 Nozzle plate
114 Nozzle holder combination

31 Nozzle needle

32 Nozzle body

33 Intermediate washer

34 Thrust pin

35 Nozzle mounting nut

36 Compression spring

37 Holding body

38 Leak-off fuel connection

40 Shim

45 Supply bore

a Fuel supply

b Leak-off fuel (return)

Nozzle holder for inclined injection

5°/180° inclined injection

Standartd production breakpoint: Standard version January 1989