Land Rover Diesel Distributor Pumps Bosch Bosch Manual

							Diesel
distributor fuel-injection pumps
Diesel-engine management
Technical Instruction 
						

							Published by:
© Robert Bosch GmbH, 1999
Postfach 30 02 20,
D-70442 Stuttgart.
Automotive Equipment Business Sector,
Department for Automotive Services,
Technical Publications (KH/PDI2).
Editor-in-Chief:
Dipl.-Ing. (FH) Horst Bauer.
Editors:
Dipl.-Ing. Karl-Heinz Dietsche,
Dipl.-Ing. (BA) Jürgen Crepin,
Dipl.-Holzw. Folkhart Dinkler,
Dipl.-Ing. (FH) Anton Beer.
Author:
Dr.-Ing. Helmut Tschöke, assisted by the
responsible technical departments of 
Robert Bosch GmbH.
Presentation:
Dipl.-Ing. (FH) Ulrich Adler,
Berthold Gauder, Leinfelden-Echterdingen.
Translation:
Peter Girling.
Photographs:
Audi AG, Ingolstadt and
Volkswagen AG, Wolfsburg.
Technical graphics:
Bauer & Partner, Stuttgart.
Unless otherwise specified, the above persons are
employees of Robert Bosch GmbH, Stuttgart.
Reproduction, copying, or translation of this
publication, wholly or in part, only with our previous 
written permission and with source credit.
Illustrations, descriptions, schematic drawings, and
other particulars only serve to explain and illustrate
the text. They are not to be used as the basis for
design, installation, or delivery conditions. We
assume no responsibility for agreement of the
contents with local laws and regulations.
Robert Bosch GmbH is exempt from liability,
and reserves the right to make
changes at any time.
Printed in Germany.
Imprimé en Allemagne.
4th Edition, April 1999.
English translation of the German edition dated:
November 1998. 
						

							Combustion in the diesel engine
The diesel engine 2
Diesel fuel-injection systems: 
An overview
Fields of application 4
Technical requirements 4
Injection-pump designs 6
Mechanically-controlled (governed)
axial-piston distributor fuel-injection
pumps VE
Fuel-injection systems 8
Fuel-injection techniques 9
Fuel supply and delivery 12
Mechanical engine-speed control 
(governing) 22
Injection timing 29
Add-on modules and 
shutoff devices 32
Testing and calibration 45
Nozzles and nozzle holders 46
Electronically-controlled axial-
piston distributor fuel-injection
pumps VE-EDC54
Solenoid-valve-controlled 
axial-piston distributor fuel-injection
pumps VE-MV60
Start-assist systems62
Diesel
distributor fuel-injection pumps VE
The reasons behind the diesel-powered
vehicle’s continuing success can be
reduced to one common denominator:
Diesels use considerably less fuel than
their gasoline-powered counterparts.
And in the meantime the diesel has
practically caught up with the gasoline
engine when it comes to starting and
running refinement. Regarding exhaust-
gas emissions, the diesel engine is just
as good as a gasoline engine with
catalytic converter. In some cases, it is
even better. The diesel engine’s emis-
sions of CO
2, which is responsible for
the “green-house effect”, are also lower
than for the gasoline engine, although
this is a direct result of the diesel
engine’s better fuel economy. It was 
also possible during the past few years
to considerably lower the particulate
emissions which are typical for the
diesel engine. 
The popularity of the high-speed diesel
engine in the  passenger car though,
would have been impossible without 
the diesel fuel-injection systems from
Bosch. The very high level of precision
inherent in the distributor pump means
that it is possible to precisely meter
extremely small injection quantities to
the engine. And thanks to the special
governor installed with the VE-pump in
passenger-car applications, the engine
responds immediately to even the finest
change in accelerator-pedal setting. All
points which contribute to the sophisti-
cated handling qualities of a modern-
day automobile.
The Electronic Diesel Control (EDC)
also plays a decisive role in the overall
improvement of the diesel-engined
passenger car.
The following pages will deal with the
design and construction of the VE distri-
butor pump, and how it adapts injected
fuel quantity, start-of-injection, and
duration of injection to the different
engine operating conditions.  
						

							The diesel engine
Diesel combustion principle
The diesel engine is a compression-
ignition (CI) engine which draws in air 
and compresses it to a very high level.
With its overall efficiency figure, the diesel
engine rates as the most efficient com-
bustion engine (CE). Large, slow-running
models can have efficiency figures of as
much as 50% or even more. 
The resulting low fuel consumption,
coupled with the low level of pollutants in
the exhaust gas, all serve to underline
the diesel engine’s significance. 
The diesel engine can utilise either the 
4- or 2-stroke principle. In automotive
applications though, diesels are practi-
cally always of the 4-stroke type (Figs. 1
and 2).
Working cycle (4-stroke)
In the case of 4-stroke diesel engines,
gas-exchange valves are used to control
the gas exchange process by opening
and closing the inlet and exhaust ports. 
Induction stroke
During the first stroke, the downward
movement of the piston draws in un-
throttled air through the open intake valve.
Compression stroke
During the second stroke, the so-called
compression stroke, the air trapped in the
cylinder is compressed by the piston
which is now moving upwards. Com-
pression ratios are between 14:1 and
24:1. In the process, the air heats up to
temperatures around 900°C. At the end
of the compression stroke the nozzle in-
jects fuel into the heated air at pressures
of up to 2,000 bar. Power stroke
Following the ignition delay, at the begin-
ning of the third stroke the finely atom-
ized fuel ignites as a result of auto-igni-
tion and burns almost completely. The
cylinder charge heats up even further
and the cylinder pressure increases
again. The energy released by the igni-
tion is applied to the piston.
The piston is forced downwards and the
combustion energy is transformed into
mechanical energy. 
Exhaust stroke
In the fourth stroke, the piston moves up
again and drives out the burnt gases
through the open exhaust valve. 
A fresh charge of air is then drawn in
again and the working cycle repeated.
Combustion chambers,
turbocharging and 
supercharging
Both divided and undivided combustion
chambers are used in diesel engines
Combustion 
in the diesel
engine
2
Combustion in the diesel
engine
Principle of the reciprocating piston engine
TDC Top Dead Center, BDC Bottom Dead Center.
V
hStroke volume, VCCompression volume,
sPiston stroke.
Fig. 1
UMM0001E
TDC
BDC TDC BDCV
h
s
VC 
						

							(prechamber engines and direct-injec-
tion engines respectively).
Direct-injection (DI) engines are more ef-
ficient and more economical than their
prechamber counterparts. For this rea-
son, DI engines are used in all commer-
cial-vehicles and trucks. On the other
hand, due to their lower noise level,
prechamber engines are fitted in passen-
ger cars where comfort plays a more im-
portant role than it does in the commer-
cial-vehicle sector. In addition, the
prechamber diesel engine features con-
siderably lower toxic emissions (HC and
NO
X), and is less costly to produce than
the DI engine. The fact though that the
prechamber engine uses slightly more
fuel than the DI engine (10...15 %) is
leading to the DI engine coming more
and more to the forefront. Compared to
the gasoline engine, both diesel versions
are more economical especially in the
part-load range. 
Diesel engines are particularly suitable
for use with exhaust-gas turbochargers
or mechanical superchargers. Using an
exhaust-gas turbocharger with the diesel
engine increases not only the power
yield, and with it the efficiency, but also
reduces the combustion noise and the
toxic content of the exhaust gas. 
Diesel-engine exhaust
emissions
A variety of different combustion deposits
are formed when diesel fuel is burnt.
These reaction products are dependent
upon engine design, engine power out-
put, and working load.
The complete combustion of the fuel
leads to major reductions in the forma-
tion of toxic substances. Complete com-
bustion is supported by the careful
matching of the air-fuel mixture, abso-
lute precision in the injection process,
and optimum air-fuel mixture turbulence.
In the first place, water (H
2O) and carbon
dioxide (CO
2) are generated. And in rela-
tively low concentrations, the following
substances are also produced:
– Carbon monoxide (CO),
– Unburnt hydrocarbons (HC),
– Nitrogen oxides (NO
X),
– Sulphur dioxide (SO
2) and sulphuric 
acid (H
2SO4), as well as
– Soot particles. 
When the engine is cold, the exhaust-gas
constituents which are immediately
noticeable are the non-oxidized or only
partly oxidized hydrocarbons which are
directly visible in the form of white or blue
smoke, and the strongly smelling alde-
hydes.
The diesel
engine
3
4-stroke diesel engine
1Induction stroke, 2Compression stroke, 3Power stroke, 4Exhaust stroke.
123 4
Fig. 2
UMM0013Y 
						

							Fields of application
Diesel engines are characterized by their
high levels of economic efficiency. This is
of particular importance in commercial
applications. Diesel engines are em-
ployed in a wide range of different ver-
sions (Fig. 1 and Table 1), for example as: 
– The drive for mobile electric generators
(up to approx. 10 kW/cylinder),
– High-speed engines for passenger
cars and light commercial vehicles (up
to approx. 50 kW/cylinder),
– Engines for construction, agricultural,
and forestry machinery (up to approx.
50 kW/cylinder),
– Engines for heavy trucks, buses, and
tractors (up to approx. 80 kW/cylinder),
– Stationary engines, for instance as
used in emergency generating sets (up
to approx. 160 kW/cylinder),
– Engines for locomotives and ships (up
to approx. 1,000 kW/cylinder).
Technical 
requirements
More and more demands are being made
on the diesel engine’s injection system as
a result of the severe regulations govern-
ing exhaust and noise emissions, and 
the demand for lower fuel-consumption.
Basically speaking, depending on the
particular diesel combustion process
(direct or indirect injection), in order to
ensure efficient air/fuel mixture formation,
the injection system must inject the fuel
into the combustion chamber at a pres-
sure between 350 and 2,050 bar, and the
injected fuel quantity must be metered
with extreme accuracy. With the diesel
engine, load and speed control must take
place using the injected fuel quantity with-
out intake-air throttling taking place. 
The mechanical (flyweight) governing
principle for diesel injection systems is in-
Diesel fuel-
injection
systems:
An overview
4
Diesel fuel-injection systems:
An overview
Overview of the Bosch diesel fuel-injection systems
M, MW, A, P, ZWM, CWin-line injection pumps in order of increasing size;PFsingle-plunger injection 
pumps; VEaxial-piston distributor injection pumps; VRradial-piston distributor injection pumps; UPSunit
pump system; UISunit injector system; CRCommon Rail system.
VE
VR
M
MW
CR
UIS PFVE
MW
A
PVE
MW
A
PZWM
CW
PF
CR
UPSZWM
CW
PF
CR
UPS VE
VR
MW
P
CR
UPS
UIS
Fig. 1
UMK1563-1Y 
						

							creasingly being superseded by the Elec-
tronic Diesel Control (EDC). In the pas-
senger-car and commercial-vehicle sec-
tor, new diesel fuel-injection systems are
all EDC-controlled.According to the latest state-of-the-art, 
it is mainly the high-pressure injection 
systems listed below which are used for
motor-vehicle diesel engines.Fields of
application, 
Technical
requirements
5
Injected fuel 
quantity per stroke
Max. nozzle
pressure
m      
Mechanical
e    
   Electronic
em 
   Electromechanical
MV 
   Solenoid valve
Direct injection
Indirect injection
DI
IDI
Pilot injection
Post injection
VE
NE
No. of cylinders
Max. speed
Max. power
per cylinder
Fuel-injection Injection Engine-related data
system
Type
mm
3bar min–1kW
In-line injection pumps
M111,601,550 m, e IDI – 4…6 5,0001,120
A11,12 01,750  m DI / IDI – 2…12 2,8001,127
MW11,150 1,100 m DI – 4…8 2,6001,136
P 300011,2501,950 m, e DI – 4…12 2,6001,145
P 710011,250 1,200 m, e DI – 4…12 2,5001,155
P 800011,250 1,300 m, e DI – 6…12 2,5001,155
P 850011,250 1,300 m, e DI – 4…12 2,5001,155
H 111,240 1,300 e DI – 6…8 2,4001,155
H 100011,250 1,350 e DI – 5…8 2,2001,170
Axial-piston distributor injection pumps
VE11,120 1,200/350 m DI / IDI – 4…64,5001,125
VE…EDC 
1)11,170 1,200/350 e, em DI / IDI – 3…64,2001,125
VE…MV11,170 1,400/350 e, MV DI / IDI – 3…64,5001,125
Radial-piston distributor injection pump
VR…MV1,1135 1,700 e, MV DI – 4.6 4,5001,150
Single-plunger injection pumps
PF(R)… 150… 800… m, em DI / IDI – arbitrary 300… 75…
18,000 1,500 2,000 1,000
UIS 30 
2)11,160 1,600 e, MV DI VE 8 3a) 3,0001,145
UIS 31 
2)11,300 1,600 e, MV DI VE 8 3a) 3,0001,175
UIS 32 
2)11,400 1,800 e, MV DI VE 8 3a) 3,0001,180
UIS-P1 
3)111,62 2,050 e, MV DI VE 6 3a) 5,0001,125
UPS 12 
4)11,150 1,600 e, MV DI VE 8 3a) 2,6001,135
UPS 20 
4)11,400 1,800 e, MV DI VE 8 3a) 2,6001,180
UPS (PF[R])13,000 1,400 e, MV DI – 6…20 1,5001,500
Common Rail accumulator injection system
CR 
5)1,100 1,350 e, MV DI VE 5a)/NE 3…8 5,000 5b)30
CR 
6)1,400 1,400 e, MV DI VE6a)/NE 6…16 2,800 200 Table 1
Diesel fuel-injection systems: Properties and characteristic data
1) EDC Electronic Diesel Control; 2) UIS unit injector system for comm. vehs. 3) UIS unit injector system for 
pass. cars; 3a) With two ECU’s large numbers of cylinders are possible; 4) UPS unit pump system for comm. 
vehs. and buses; 5) CR 1st generation for pass. cars and light comm. vehs.; 5a) Up to 90˚ crankshaft BTDC, 
freely selectable; 5b) Up to 5,500 min–1 during overrun; 6) CR for comm. vehs., buses, and diesel-powered 
locomotives; 6a) Up to 30˚ crankshaft BTDC.   
						

							Injection-pump 
designs
In-line fuel-injection pumps
All in-line fuel-injection pumps have a
plunger-and-barrel assembly for each
cylinder. As the name implies, this com-
prises the pump barrel and the corre-
sponding plunger. The pump camshaft
integrated in the pump and driven by the
engine, forces the pump plunger in 
the delivery direction. The plunger is re-
turned by its spring. 
The plunger-and-barrel assemblies are
arranged in-line, and plunger lift cannot
be varied. In order to permit changes in
the delivery quantity, slots have been
machined into the plunger, the diagonal
edges of which are known as helixes.
When the plunger is rotated by the mov-
able control rack, the helixes permit the
selection of the required effective stroke.
Depending   upon the fuel-injection con-
ditions, delivery valves are installed be-
tween the pump’s pressure chamber and
the fuel-injection lines. These not only
precisely terminate the injection process
and prevent secondary injection (dribble)
at the nozzle, but also ensure a family 
of uniform pump characteristic curves
(pump map). 
PE standard in-line fuel-injection pump
Start of fuel delivery is defined by an inlet
port which is closed by the plunger’s top
edge. The delivery quantity is determined
by the second inlet port being opened by
the helix which is diagonally machined
into the plunger.
The control rack’s setting is determined
by a mechanical (flyweight) governor or
by an electric actuator (EDC).
Control-sleeve in-line fuel-injection
pump
The control-sleeve in-line fuel-injection
pump differs from a conventional in-line
injection pump by having a “control
sleeve” which slides up and down the
pump plunger. By way of an actuator shaft,
this can vary the plunger lift to port closing,and with it the start of delivery and the start
of injection. The control sleeve’s position
is varied as a function of a variety of dif-
ferent influencing variables. Compared 
to the standard PE in-line injection pump
therefore, the control-sleeve version fea-
tures an additional degree of freedom.
Distributor fuel-injection
pumps
Distributor pumps have a mechanical
(flyweight) governor, or an electronic
control with integrated timing device. The
distributor pump has only one plunger-
and-barrel asembly for all the engine’s
cylinders.
Axial-piston distributor pump
In the case of the axial-piston distributor
pump, fuel is supplied by a vane-type
pump. Pressure generation, and distribu-
tion to the individual engine cylinders, is
the job of a central piston which runs on
a cam plate. For one revolution of the
driveshaft, the piston performs as many
strokes as there are engine cylinders.
The rotating-reciprocating movement is
imparted to the plunger by the cams on
the underside of the cam plate which ride
on the rollers of the roller ring. 
On the conventional VE axial-piston dis-
tributor pump with mechanical (flyweight)
governor, or electronically controlled
actuator, a control collar defines the
effective stroke and with it the injected
fuel quantity. The pump’s start of delivery
can be adjusted by the roller ring (timing
device). On the conventional solenoid-
valve-controlled axial-piston distributor
pump, instead of a control collar an 
electronically controlled high-pressure
solenoid valve controls the injected fuel
quantity. The open and closed-loop con-
trol signals are processed in two ECU’s.
Speed is controlled by appropriate trig-
gering of the actuator.
Radial-piston distributor pump
In the case of the radial-piston distributor
pump, fuel is supplied by a vane-type
pump. A radial-piston pump with cam ring
and two to four radial pistons is responsible
Diesel fuel-
injection
systems:
An overview
6 
						

							for generation of the high pressure and for
fuel delivery. The injected fuel quantity is
metered by a high-pressure solenoid
valve. The timing device rotates the cam
ring in order to adjust the start of delivery.
As is the case with the solenoid-valve-
controlled axial-piston pump, all open and
closed-loop control signals are processed
in two ECU’s. Speed is controlled by
appropriate triggering of the actuator.
Single-plunger fuel-injection
pumps
PF single-plunger pumps
PF single-plunger injection pumps are
used for small engines, diesel locomo-
tives, marine engines, and construction
machinery. They have no camshaft of
their own, although they correspond to
the PE in-line injection pumps regarding
their method of operation. In the case of
large engines, the mechanical-hydraulic
governor or electronic controller is at-
tached directly to the engine block. The
fuel-quantity adjustment as defined by
the governor (or controller) is transferred
by a rack integrated in the engine. 
The actuating cams for the individual PF
single-plunger pumps are located on the
engine camshaft. This means that injec-
tion timing cannot be implemented by
rotating the camshaft. Here, by adjusting
an intermediate element (for instance, a
rocker between camshaft and roller tap-
pet) an advance angle of several angular
degrees can be obtained.
Single-plunger injection pumps are also
suitable for operation with viscous heavy
oils.
Unit-injector system (UIS)
With the unit-injector system, injection
pump and injection nozzle form a unit.
One of these units is installed in the en-
gine’s cylinder head for each engine cyl-
inder, and driven directly by a tappet or
indirectly from the engine’s camshaft
through a valve lifter. 
Compared with in-line and distributor in-
jection pumps, considerably higher injec-
tion pressures (up to 2050 bar) have be-come possible due to the omission of the
high-pressure lines. Such high injection
pressures coupled with the electronic
map-based control of duration of injection
(or injected fuel quantity), mean that a
considerable reduction of the diesel en-
gine’s toxic emissions has become possi-
ble together with good shaping of the
rate-of-discharge curve. 
Electronic control concepts permit a va-
riety of additional functions. 
Unit-pump system (UPS)
The principle of the UPS unit-pump sys-
tem is the same as that of the UIS unit 
injector. It is a modular high-pressure in-
jection system. Similar to the UIS, the
UPS system features one UPS single-
plunger injection pump for each engine
cylinder. Each UP pump is driven by the
engine’s camshaft. Connection to the no-
zzle-and-holder assembly is through a
short high-pressure delivery line preci-
sely matched to the pump-system com-
ponents.
Electronic map-based control of the start
of injection and injection duration (in
other words, of injected fuel quantity)
leads to a pronounced reduction in the
diesel engine’s toxic emissions. The use
of a high-speed electronically triggered
solenoid valveenables the character-
istic of the individual injection process,
the so-called rate-of-discharge curve, to
be precisely defined. 
Accumulator injection
system
Common-Rail system (CR)
Pressure generation and the actual injec-
tion process have been decoupled from
each other in the Common Rail accumu-
lator injection system. The injection pres-
sure is generated independent of engine
speed and injected fuel quantity, and is
stored, ready for each injection process,
in the rail (fuel accumulator). The start of
injection and the injected fuel quantity
are calculated in the ECU and, via the in-
jection unit, implemented at each cylin-
der through a triggered solenoid valve. 
Injection-pump
designs
7 
						

							Fuel-injection
systems
Assignments
The fuel-injection system is responsible
for supplying the diesel engine with fuel.
To do so, the injection pump generates
the pressure required for fuel injection.
The fuel under pressure is forced through
the high-pressure fuel-injection tubing to
the injection nozzle which then injects it
into the combustion chamber.
The fuel-injection system (Fig. 1) in-
cludes the following components and
assemblies: The fuel tank, the fuel filter,
the fuel-supply pump, the injection
nozzles, the high-pressure injectiontubing, the governor, and the timing
device (if required). 
The combustion processes in the diesel 
engine depend to a large degree upon
the quantity of fuel which is injected and
upon the method of introducing this fuel
to the combustion chamber. 
The most important criteria in this re-
spect are the fuel-injection timing and the
duration of injection, the fuel’s distribution
in the combustion chamber, the moment
in time when combustion starts, the
amount of fuel metered to the engine per
degree crankshaft, and the total injected
fuel quantity in accordance with the
engine loading. The optimum interplay of
all these parameters is decisive for the
faultless functioning of the diesel engine
and of the fuel-injection system.
Axial-piston
distributor
pumps
8
Mechanically-controlled
(governed) axial-piston distributor
fuel-Injection pumps VE
Fuel-injection system with mechanically-controlled (governed) distributor injection pump
1Fuel tank, 2Fuel filter, 3Distributor fuel-injection pump, 4Nozzle holder with nozzle, 5Fuel return line, 
6Sheathed-element glow plug (GSK) 7Battery, 8Glow-plug and starter switch, 9Glow control unit (GZS).
 



















 






















1
26
5
4
9
73
8
Fig. 1
UMK1199Y