Land Rover Diesel Distributor Pumps Bosch Bosch Manual

Injection timing
In order to compensate for the injection
lag and the ignition lag, as engine 
speed increases the timing device 
advances the distributor pump’s start 
of delivery referred to the engine’s
crankshaft. Example (Fig. 1):
Start of delivery (FB) takes place after
the inlet port is closed. The high pres-
sure then builds up in the pump which, 
as soon as the nozzle-opening pres-
sure has been reached leads to the 
start of injection (SB). The period
between FB and SB is referred to as the...

order to atomize and mix with the air to
form an ignitable mixture.
This is termed the air-fuel mixture
preparation time and is independent of 
engine speed. In a diesel engine, the
time required between start of injection
and start of combustion is termed the 
ignition lag.
The ignition lag is influenced by the 
diesel fuel’s ignition quality (defined by
the Cetane Number), the compression
ratio, the intake-air temperature, and 
the quality of fuel atomization. As a 
rule, the ignition lag is in the...

through a sliding block and a pin so that
piston movement can be converted to
rotational movement of the roller ring.
Method of operation
The timing-device piston is held in its 
initial position by the timing-device spring
(Fig. 3a). During operation, the pressure-
control valve regulates the fuel pressure
inside the pump so that it is proportional
to engine speed. As a result, the engine-
speed-dependent fuel pressure is ap-
plied to the end of the timing-device
piston opposite to the spring.
As from...

Add-on modules
and shutoff devices
Application
The distributor injection pump is built 
according to modular construction
principles, and can be equipped with a 
variety of supplementary (add-on) units 
(Fig. 1). These enable the implemen-
tation of a wide range of adaptation 
possibilities with regard to optimization 
of engine torque, power output, fuel 
economy, and exhaust-gas composition.
The overview provides a summary of the add-on modules and their effects
upon the diesel engine. The schematic...

Add-on
modules
and shutoff
devices
33Schematic of the VE distributor pump with mechanical/hydraulic full-load torque control
LDA Manifold-pressure compensator.
Controls the delivery quantity as a function of the charge-air pressure.
HBA Hydraulically controlled torque control.
Controls the delivery quantity as a function of the engine speed (not for pressure-charged engines 
with LDA).
LFB Load-dependent start of delivery.
Adaptation of pump delivery to load. For reduction of noise and exhaust-gas...

to install torque control. In other words,
the engine should receive precisely the
amount of fuel it needs. The engine’s 
fuel requirement first of all climbs as a 
function of engine speed and then levels
off somewhat at higher speeds. The 
fuel-delivery curve of an injection pump
without torque control is shown in Fig. 3.
As can be seen, with the same setting of
the control collar on the distributor
plunger, the injection pump delivers
slightly more fuel at high speeds than it
does at lower speeds....

the torque-control lever tilts around the
stop pin (5) and forces the torque-
control pin (7) in the direction of the 
stop, while the starting lever (1) swivels
around the pivot point (M
2) and forces the
control collar (8) in the direction of re-
duced fuel delivery. Torque control ceases
as soon as the torque-control-pin collar
(10) abuts against the starting lever (1).
Negative torque control
Negative torque control may be 
necessary in the case of engines which
have black-smoke problems in the...

Manifold-pressure
compensation
Exhaust-gas turbocharging
Because it increases the mass of air 
inducted by the engine, exhaust turbo-
charging boosts a diesel engine’s power
output considerably over that of a nat-
urally aspirated diesel engine, with little
increase in dimensions and engine
speeds. This means that the brake 
horsepower can be increased corre-
sponding to the increase in air mass 
(Figure 6). In addition, it is often possible 
to also reduce the specific fuel con-
sumption. An exhaust-gas...

Manifold-pressure compensator
(LDA)
The manifold-pressure compensator
(LDA) reacts to the charge-air pressure
generated by the exhaust-gas turbo-
charger, or the (mechanical) super-
charger, and adapts the full-load deliv-
ery to the charge-air pressure (Figs. 6
and 7).
Assignment
The manifold-pressure compensator
(LDA) is used on pressure-charged 
diesel engines. On these engines the 
injected fuel quantity is adapted to 
the engine’s increased air charge (due to
pressure-charging). If the pressure-...

jected fuel quantity must be adapted 
to the lower air mass. This is performed
by the manifold-pressure compensator
which, below a given (selectable)
charge-air pressure, reduces the full-load
quantity.
Design and construction
The LDA is mounted on the top of the
distributor pump (Fig. 7). In turn, the top
of the LDA incorporates the connection
for the charge-air and the vent bore. The 
interior of the LDA is divided into two 
separate airtight chambers by a dia-
phragm to which pressure is applied by 
a...