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Iveco Daily Euro 4. Manual - part 34

75532

Figure 262

A. THROTTLE VALVE SHUT

It is basically composed of:

- a central casing housing a shaft supported by bushings at

whose opposite ends are fitted the turbine wheel and
the compressor rotor;

- a turbine casing and a compressor casing mounted on

the end of the central body;

- an overpressure relief valve fitted on the turbine casing.

Its function is to choke the exhaust gas outlet (detail B),
sending a portion of the exhaust gas straight into the
exhaust

pipe

when

the

turbocharging

pressure

downstream from the turbocharger reaches the setting.

542410

Turbocharger (KKK K03-2074-CCB 5.88 type)

75533

B. THROTTLE VALVE OPEN

Figure 263

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88622

Figure 264

Figure 265

88623

Cover the air, exhaust gas and lubricating oil inlets and
outlets. Thoroughly clean the outside of the turbocharger
using anticorrosive and antioxidant fluid. Disconnect the pipe
(2) from the union of the pressure relief valve (1) and fit on
it the pipe of the device 99367121 (3, Figure 265).

542418

Pressure relief valve

Checking pressure relief valve

Rest the tip of the dial gauge (1) with a magnetic base on the
end of the tie rod (2) and zero it. Using the device 99367121
(3), introduce compressed air into the valve casing (4) at the
prescribed pressure and make sure this value stays constant
throughout the check; replace the valve if it doesn’t. In the
above conditions, the tie rod must have made the prescribed
travel.

On finding irregular engine operation due to the
turbocharging system, it is first expedient to
perform the checks on the turbocharger, check the
efficiency of the seals and the fixing of the couplings,
additionally checking there is no clogging in the
intake sleeves, air filter or radiators. If the
turbocharger damage is due to a lack of lubrication,
check that the oil circulation pipes are not burst or
clogged, in which case replace them or eliminate
the trouble.

NOTE

Before fitting the turbocharger on the engine, it is
necessary to fill the central body with engine
lubricating oil.

NOTE

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62870

Figure 266

542410

GARRET GT 17 variable
geometry turbosupercharger
(engine F1A E0481 H - 136 HP)

General

The variable geometry turbosupercharger consists of the
following:
- centrifugal supercharger (1);
- turbine (2);
- set of mobile blades (3);
- mobile blade control pneumatic actuator (4), vacuum

controlled by proportional solenoid valve controlled by
EDC 16 ECU.

Variable geometry enables:
- to increase the speed of the exhaust gases running into

the turbine at low engine rpm;

- to decrease the speed of the exhaust gases running into

the turbine at high engine rpm.

To obtain the max. engine volumetric efficiency also at low
rpm (with on-load engine).

Operation at low engine rpm

1. TURBINE - 2. MOBILE BLADES - 3. PNEUMATIC ACTUATOR - 4. REVOLVING RING

Operation at high engine rpm

82871

Figure 267

62872

Figure 268

When engine is running at low speed, the exhaust gases
show weak kinetic energy; under these conditions a
traditional turbine shall rotate slowly, thus providing a limited
booster pressure.
In the variable geometry turbine (1), the mobile blades (2) are
set to max. closed position and the small through-sections
between the blades increase the inlet gas speed. Higher inlet
speeds involve higher tip speeds of the turbine and therefore
of the turbosupercharger.
Engine speed increase results in a gradual increase of exhaust
gas kinetic energy, and also in turbine (1) speed and booster
pressure increase.

The ECU, through the actuator control solenoid valve,
modulates the vacuum acting on the diaphragm, so actuator
(3) controls through the tie rod, the gradual opening of the
mobile blades (2) until reaching the max. open position.
Blade through-sections results larger thus producing a speed
decrease in exhaust gas flow through the turbine (1) with
speeds equal to or lower than those of the low rpm
condition.
Turbine (1) speed is therefore adjusted to a proper value
enabling suitable engine operation at high speeds.

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Proportional

solenoid

valve

controlling

turbocharger actuator

62876

Figure 269

The solenoid valve modulates the low pressure controlling
the turbocharger actuator, taken from the air circuit of the
servo brake, according to the information exchanged
between the electronic control unit and the sensors: engine
speed, throttle pedal position and pressure/temperature
fitted on the intake manifold.

As a result, the actuator varies the opening of the blades of
the turbocharger that adjust the flow of exhaust gases.

62869

TURBOCHARGING FUNCTIONAL DIAGRAM

1. Variable geometry turbocharger - 2. Pneumatic actuator - 3. Proportional solenoid valve - 4. Air filter -

5. EDC 16 control unit - 6. Servo brake - 7. Vacuum device - 8. High-pressure pump.

Figure 270

The actuator diaphragm, connected to the control rod, is
governed by the low pressure on the top of the actuator.

The low pressure modulated by the proportional solenoid
valve varies the movement of the diaphragm and, as a result,
of the rod governing the turbine’s mobile blades.

62875

SECTION ON THE ACTUATOR

Figure 271

Actuator

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