2001 FIAT MAREA Control unit

Marea-Marea Weekend 9 -™ Engine
2000 range (j§) Fuel feed system
10.
I I TEST
4F017XJ01
A switch (1) on the brake pedal con­
trols the car brake lights; the same
switch sends a signal to pin 59 of the
injection control unit
The control unit uses the "brake pedal
depressed" signal to:
- detect a situation of over-run;;
- check the plausibility of the signal
from the accelerator potentiometer
CLUTCH PEDAL SWITCH
A switch (2) on the clutch pedal is connected to pin 61 of the injection control unit.
The injection control unit uses the "brake pedal operated" signal to distinguish gear engaged and gear
shift conditions.
PRESSURE RELIEF SENSOR
The sensor is fitted to the intake manifold and
the signal sent to the injection control unit is
used to:
- regulate injection pressure;
- regulate injection duration.
The figure alongside shows the sensor and
electrical connector with the following pin-
out:
1. pressure signal
2. Earth
3. Fuel feed system
ATMOSPHERIC PRESSURE SENSOR
The atmospheric pressure signal is built into the injection control unit. It is responsible for measuring at­
mospheric pressure in order to correct measured air flow and reference air flow values to control the EGR
function.
Copyright by Fiat Auto 17

Marea- Marea Weekend 9 ™
2000 range (Q)
4F019XJ01
1. Impeller
2. Volumes
3. Intake port
4. Outlet port
5. Rollers
6. Outer race
7. Pressure relief valve
4F019XJ02
Engine
Fuel feed system
10.
SUBMERGED FUEL PUMP ASSEMBLY
(AUXILIARY) AND LEVEL GAUGE CON­
TROL
The assembly consists mainly of:
- a roller-type fuel pump;
- a fuel level gauge;
- a fuel filter
The submerged fuel pump is volumetric type
with rollers and a motor with brushes and
permanent magnet excitation.
Impeller (1) is driven by the electric motor to
turn and create volumes (2) that move from
intake port (3) to outlet port (4).
These volumes are delimited by rollers (5) that
adhere to outer race(6) as the motor turns.
The pump is fitted with two valves: a check
valve to prevent the fuel circuit emptying
(with the pump off); a second pressure relief
valve (7) that short-circuits the outlet to the
inlet when pressures exceed 5 bars.
FUEL FILTER
The fuel filter is located in the engine bay.
The filter is cartridge type with a filter element
(1) made up of a pack of paper discs with a
filtering area of some 5300 cm 2 and a filter
gauge of 4 - 5 microns.
The filter is equipped with a fuel preheating
device (2) controlled by the engine control
unit via a relay.
The control unit activates or deactivates the
diesel filter on the basis of a diesel tempera­
ture signal sent by sensor (3) on the filter.
A plug (4) screwed to the base of the fuel
filter cartridge is used to drai off the water.
The plug incorporates a sensor for the detec­
tion of water in the diesel filter connected to a
warning light on the instrument panel.
1. Filter cartridge
2. Diesel preheating device
3. Diesel temperature sensor
4. Water drain plug with sensor to detect
presence of water in diesel filter
Copyright by Fiat Auto 19

Engine
Fuel feed system
JTD Marea-Marea Weekend @
2000 range ©
10.
7^ £3
PRESSURE PUMP
The pressure pump is radialjet type with three
radial pistons (total capacity 0.657 cc). It is
controlled by a timing belt with or without
timing requirements.
Each pump unit consists of:
a piston (5) opered by a cam (2) integral with
the pump shaft (6);
a plate-type intake valve (3);
a delivery ball valve (4).
The pressure pump must be supplied at a
pressure of at least 0.5 bars; and for this rea­
son the fuel system is equipped with an aux­
iliary pump submerged in the tank.
The pressure pump is lubricated and cooled
by the diesel fuel via channels and is able to
deliver a maximum pressure of 1350 bars.
1.
2.
3.
4.
5.
6.
7.
8.
Cylinder
Cam
Plate-type intake valve
Ball-type delivery valve
Piston
Pump shaft
Diesel intake connection -
from fuel filter
Diesel delivery connection
to manifold (rail)
Diesel delivery connection
recirculation
low pressure
high pressure
low pressure
PRESSURE REGULATOR
FILTER
The fuel pressure regulator is fitted to the
pressure pump and controlled directly by the
injection control unit. It regulates fuel feed
pressure to the injectors.
The pressure regulator consists mainly of the
following parts:
1. Ball plunger
2. Pin
3. Valve
4. Preload spring
5. Coil
6. Body
7. Anchor
20 Publication no. 506.763/24

Engine Marea- Marea Weekend 9*nD
Fuel feed system 2000 range (§)
10.
THROTTLE BODY
To reduce engine noise during shut-down, a throttle has been added to the intake port with the aim of
closing off the air flow to the cylinders.
Throttle valve opening or closure is controlled by an engine control unit (5) that manages a control ac­
tuator (3) on throttle body (4) via solenoid (2).
Operation
When the engine is off, the throttle is open because no vacuum is present.
When the engine is running, the throttle is open because the Pierburg solenoid is not activated and pre­
vents the vacuum reaching the pneumatic actuator.
A vacuum builds up in the tank during engine operation.
During engine shut-down (when the ignition key is turned OFF), the control unit keeps the actuator sup­
ply relay activated for a further 4 or 5 seconds and simultaneously earths the Pierburg valve. The Pierburg
valve opens to send the vacuum that has built up in the vacuum tank to the pneumatic actuator, which
closes the throttle to cut off the flow of air to the cylinders.
4F024XJ01
1. Vacuum tank;
2. Pierburg solenoid controlling throttle body
actuator;
3. Pneumatic actuator on throttle body
4. Throttle body
5. Engine control unit
6. Vacuum pump
24 Publication no. 506.763/24

Marea- Marea Weekend 9
2000 range ©
Engine
Fuel feed system
10.
TURBOCHARGER (1910 JTD 110 CV)
The turbocharger used in the application of the
EURO 3 standards in the variable geometry
type connected to the exhaust manifold.
The turbocharger is controlled by the engine
management control unit via a duty-cycle so­
lenoid valve.
The increased volumetric output for the engine
is achieved, in the case of variable geometry
compressors, through the use of:
- a centrifugal compressor (1)
- a turbine (2)
- a series of moving vanes (3)
- a pneumatic actuator (4) controlling the
moving vanes.
- asolenoid valve (5) controlling the actuator
The variable geometry turbocharger makes it
possible to:
- increase the speed of the exhaust gases in
the turbine at low engine speeds
- slow down the speed of the exhaust gases
in the turbine at high speeds.
The control of the speed (kinetic energy) of
the exhaust gases makes it possible to pro­
duce increased engine torque at low speeds
and greater maximum power at high speeds.
Operation at low rotation speeds
When the engine is operating at low speeds,
the exhaust gases possses little kinetic energy:
under these circumstances a conventional tur­
bine would rotate slowly, supplying a limited
supercharging pressure.
On the other hand, in the variable geometry
turbine (1), the moving vanes are in the
maximum closure position and the small pas­
sage sections between the vanes increase the
speed (C) of the intake gases.
Increased intake speeds lead to increased pe­
ripheral speeds (U) of the turbine and, conse­
quently, the compressor.
The speed of the gases inside the impeller is
indicated by the vector (W).
1. Turbine
2. Moving vanes
3. Pneumatic actuator
4. Rotary seal
Copyright by Fiat Auto r VI-01-Cancels arwl replaces.25

Engine
Fuel feed system
JTD Marea- Marea Weekend 9
2000 range @
10.
Operation at high rotation speeds
When the engine speed is increased, the ki­
netic energy of the exhaust gases increases
gradually.
As a result, the speed of the turbine (5) in­
creases and consequently the supercharging
pressure.
The VGT solenoid valve (2) operated by the
injection control unit (1), through the actuator
(4) causes the moving vanes to change posi­
tion until the maximum opening position is
reached.
1. Injection control unit
2. VGT solenoid valve
3. Vacuum reservoir
4. Pneumatic actuator
5. Turbine
There is therefore an increase in the passage
sections and consequently a slowing down in
the flow of exhaust gases which pass through
the turbine (1) at the same speed or slower
than the low speed conditions.
The speed of the turbine (1) decreases and
settles down at a suitable vaule for the correct
operation of the engine at high speeds.
1. Turbine
2. Moving vanes
3. Pneumatic actuator
4. Rotary seal
TURBOCHARGER (1910 JTD 100 CV)
It basically consists of two impellers (1) on
one shaft (2) which rotates on floating bear­
ings lubricated by a duct (3) from the engine
lubrication circuit.
The oil used dissipates some of the large
amount of heat given off by the exhaust gases
at the turbine.
There is a waste gate valve (4) fitted on the
turbocharger, operated by a pneumatic actua­
tor (5), that makes it possible to shutter the
flow of exhaust gases to the turbine, accord­
ing to the engine power/torque requirements.
The pneumatic actuator is controlled by the en­
gine management control unit via a solenoid
valve.
* The turbocharger used on the 1910 JTD 100 CV version is the fixed geometry type.
26 VI 0^ Cam.frtfi and ri!plact<& Print n° 506.763/25

Engine Marea- Marea Weekend IP ™
Fuel feed system 2000 range o
10.
The EGR valve consists of:
- a Pierburg EGR solenoid (1) operated by engine management unit (2)
- a pipe from the exhaust manifold (4) (from which the exhaust gases flow)
- an air-water heat exchanger (3) (that lowers exhaust gas temperature)
- a pipe connected to throttle body (5) to which exhaust gases are admitted
4
Operation
With coolant temperature > 20°C and engine speeds between 800 and 3000 rpm, the engine management
unit controls the EGR solenoid by means of a square wave signal.
Changes in this signal allow the EGR coil to move a plunger and thus modulate the flow of exhaust gas
from the exhaust manifold to the intake manifold; this achieves two results:
- less air is taken in
- combustion temperature is lowered (due to the presence of inert gases), thus reducing the formation of
NOx (nitrogen oxides).
The engine management control unit is constantly informed of recirculation gas quantity via data from the
debimeter. If the intake of a given quantity of air (Qam) is required for a given rpm and the level sent by
the debimeter (Qar) is lower, the difference (Qgr) is the amount of gas recirculated.
Qam - Qar = Qgr
Qam = stored theoretical air quantity
Qar = actual air quantity
Qgr = recirculated gas quantity
An atmospheric pressure signal is used in controlling the EGR valve to detect when the car is being driven at
altitude. The recirculation gas quantity can then be reduced to prevent engine fumes.
28 Publication no. 506.763/24

Marea- Marea Weekend
2000 range ©
Auxiliary Units
Climate control
50
COMPRESSOR ( 1596 engine)
The compressor fitted on this version is the HR V5 variable capacity type, illustrated in the diagram below,
and consists of:
- a crankcase (7) which contains the bores in which the pistons (4) slide;
- an assembly comprising a shaft on which an inclined plate (6) is fitted on which a disc (2) guided by
a pin (5) integral with the five connecting rods (3) controlled by the pistons (4) rotates on roller bear­
ings;
- a cylinder head which contains the intake and supply ducts as well as the housing for the regulation
valve (9);
- a plate (8), between the crankcase and the cylinder head, which contains the inlet and supply valves;
- a pulley assembly with an electro-magnet coupling (1).
1. Pulley with coupling
2. Disc
3. Connecting rod
4. Piston
5. Disc guide pin
6. Inclined plate
7. Crankcase
8. Valve holder plate
9. Regulation valve
10. Valve control bellows
Operation
The alternating drive required for the sliding of the pistons in the bores/liners is produced by the rotary
motion of the inclined plate (6), whilst the variation in the capacity, dependent on the piston stroke, is
chieved through the alteration in the angle of the disc (2) controlling the connecting rods (3).
The inclination of the above mentioned disc depends on the difference in pressure between the intake
duct and the inside of the compressor. This difference, measured by the bellows (10), operates the regu­
lation valve (9) and consequently causes the movement of the disc (2).
When the request for conditioned air is high, the regulation valve (9) is positioned in such a way that it
uncovers an opening which places the intake side in contact with the inside of the compressor; as, in this
case, there is no difference in pressure, the compressor operates at maximum capacity corresponding to
the position of the disc illustrated in the previous section.
When the air request is less, the valve is positioned so that the supply section is in contact with the crank­
case and, at the same time, it stops the flow between the latter and the intake side activated previously.
Copyright by Fiat Auto 1