SsangYong Rexton. Service manual - part 447

SSANGYONG  Y200

1F3-8  DIESEL ENGINE CONTROLS

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Torque control

If torque control is fitted, full-load delivery quantity is

reduced when a given speed n

1

 is exceeded, because

centrifugal force acting on sliding sleeve (20) exceeds
the force of the torque-control spring fitted in spring
retainer (18). The torque-control spring yields to this
force. As a result, if speed increases further, control
rack (4) shifts by the torque-control travel distance.
Torque control ends at speed n

2

.

Instead of positive torque control, the RDF governor
can have negative torque control. Here the control-rack
setting is controlled by a spring combination.

High idle (maximum) speed

With the accelerator pedal pressed to the floor, the
full-load quantity is injected until the maximum full-

4 Control Rack

17 Governor Spring
18 Spring Retainer (Torque Control)

Full-load setting

(only the components concerned in the governing process are shown)

20 Governor Sliding Sleeve
22 Flyweight

load speed n

vo

 is reached. If engine speed increases

beyond full-load speed, the force exerted by the
flyweights (22) suffices to overcome the force of
governor spring (17) and full-load-speed regulation
starts.

Engine speed increases slightly, and rack travel is
reduced due to the rack being moved towards stop
(shutoff) and the delivery quantity decreases.

Breakaway depends upon governor spring pretension.
The engine adjusts to high idle (maximum) speed n

10

when all load is removed.

When driving downhill with the accelerator released,
the vehicle drives the engine (overrun) and accelerates
it.

No fuel is injected during this operating mode (overrun
fuel shutoff).

DIESEL ENGINE CONTROLS  1F3-9

SSANGYONG  Y200

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Stopping the engine

When Stop (shutoff) lever (1) is moved by hand, stop
lever (3) shifts control rack (4) to the Stop (shutoff)
position. The fuel supply is interrupted and the engine
stops. A pneumatic shutoff device can also be used
for engine switchoff.

Switching off

The vacuum unit (6) is connected to vacuum from the
vacuum pump via the glow starter switch of the vehicle.

As a result, the diaphragm of the vacuum unit is pulled
against the compression spring.

The vacuum unit (6) is connected with a stop lever
(2r). This lever pivots around the fulcrum “D” pulling
the control rod of the injection pump into the “stop
position”. The bypass spring of the fulcrum lever is
overcome in this process. Via the emergency stop lever
(2s) the control rod can likewise be pulled into “stop
position” on the outside of the governor.

a Start

b Stop

SSANGYONG  Y200

1F3-10  DIESEL ENGINE CONTROLS

1 Adjusting Screw
2 Aneroid Box
3 Connection for the Line to the Engine Manifold

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ABSOLUTE METERING MANIFOLD
PRESSURE COMPENSATOR
(ALDA)

On a pressure-charged engine, the cylinder air charge
depends upon the boost pressure, which in turn is
influenced by the prevailing atmospheric pressure. The
effects of variants in atmospheric pressure have an
e s p e c i a l l y   l a r g e   i n f l u e n c e   w h e n   c o n s i d e r a b l e
differences in attitude are encountered in driving.

Because the engine’s turbocharger further compresses
the prevailing atmospheric pressure, the absolute
pressure in the engine’s intake manifold is a
combination of the atmospheric pressure and the
charge-air pressure. The absolute-metering manifold-
pressure compensator registers this absolute pressure
and adapts the fuel-delivery quantity accordingly.

4 Aneroid Capsule
5 Adaptation
6 Guide Plate

DIESEL ENGINE CONTROLS  1F3-11

SSANGYONG  Y200

PNEUMATIC IDLE SPEED
INCREASE (PLA)

Application

The injected fuel quantity needed by a diesel engine
at idle decreases along with increasing engine
temperature.

When the engine is cold, the temperature-dependent
idle-speed increase fitted to the RSF governor raises
the idle speed accordingly, there by improving the
engine’s warm-up behaviour. It also prevents the cold
engine stalling when additional loads are switched,
such as power-assisted steering, air-conditioner, etc.

The PLA ceases to function above a certain temperature.

Design and Function

Depending upon temperature, pressure is applied to

the aneroid capsule’s diaphragm which in turn shifts
a sliding bolt to change the pretension on the idle
spring. The control rack now moves towards “increased
fuel quantity” via the governor linkage and the control
rack.

Operation

Coolant temparature <0°c

The thermovalve is open. The vacuum of approx. 700
mbar reaches the vacuum unit idle speed increase via
the thermovalve. The idle speed is increased by approx
100/min. The choke in the ventilation filter causes a
pressure loss of approx 100 mbar.

Coolant temperature >0° c

The thermovalve is closed. Atmospheric pressure
reaches the vacuum unit through the choke in the
ventilation filter. The speed increase is cancelled.