Chery Karry A18 2010 2016, Karry A18 2007, Karry A18 2008, Karry A18 2009 User Manual
CLUTCH
CLUTCH INTRODUCTION… … … … … … … … … … … … … … … … … … F-2
CLUTCH STRUCTURE … … ……………… … … … … … … … … … …F-2
OPERATING PRINCIPLE OF CLUTCH … … … … … … … … … … … …F-2
CLUTCH CABLE ASSEMBLY STRUCTURE … … … … … … … … … …F-3
ASSEMBLY AND ADJUSTMENT OF CLUTCH CABLE … … … … … … … …F-4
CLUTCH DISASSEMBLY …… … … … … … … … … … … … … … … … …F-5
CLUTCH OVERHAUL ………… … … … … … … … … … … … … … … … …F-6
CLUTCH INSTALLATION… … … … … … … … … … … … … … … … … …F-7
TROUBLE DIAGNOSIS………… … … … … … … … … … … … … … … … …F-8
F-1
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CLUTCH INTRODUCTION
CLUTCH STRUCTURE
·As picture below, the clutch is dry diaphragm with single leaf. It consists of clutch driven
disk (2), release disk (4), intermediate disk (6), pressure plate (7) and flywheel (1).
·There are diaphragm springs in the pressure plate (7), which are fixed in the crankshaft by
intermediate disk (6) and bolt (5). Driven disk (2) is pressed on the flywheel (1) by
pressure plate (7), and bolt (8) is used to fix pressure plate (7) and flywheel (1) together;
the clutch pusher (9) is used to push separator disk (4) and then the separator disk (4) to
push the small end of diaphragm springs on pressure plate (7).
1.Flywheel 2.Driven Disk 3.Snap Ring 4.Release Disk 5.Bolt（M10）(110±5N.m)
6.Intermediate Disk 7.Pressure Plate 8.Bolt (23~25N.m) 9.Clutch Pusher
OPERATING PRINCIPLE OF CLUTCH
·As picture below, Picture a presents the connection status of clutch. When clutch pedal is
not treaded, the driven disk (3) is pressed on flywheel (2) by diaphragm spring (1). Driven
disk (3) and flywheel (2) are revolving synchronously, and the torque is transmitted to the
transmission-axle (6) by Separator disk (5) through driven disk (3).
·Picture b presents the disconnection state of clutch. When the clutch is treaded, pusher (4)
pushes separator disk (5) which presses the small end of diaphragm spring (1) to move the
big end of diaphragm spring (1) away from driven disk (3), so the pressure is disengaged
between driven disk (3) and flywheel (2) and the clearance is generated to cut off the
motive power of engine and pass the transmission.
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in 6.Jacket
st Cover 10.Adjust Rod 11.Jam Nut 12.Adjust Bushing
a. Clutch Connection State b. Clutch Disconnection State
1.Diaphragm Spring 2.Flywheel 3.Driven Disk 4.Pusher
5.Seperator Disk 6.Transmission Axle
CLUTCH CABLE ASSEMBLY STRUCTURE
1.Clip 2.Cable Latch 3.Washer 4.Cable Cushion 5.Jacket Tie-
7.Inner Pipe 8.Cable 9.Du
13.Clip Ring 14.Retainer 15.Washer 16.Rubber Cushion 17.Gasket 18. Butt End
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ASSEMBLY AND ADJUSTMENT OF CLUTCH CABLE
estern
Move direction of release
disk after driven disk wear
When driven disk wear down,
unscrew the nuts and adjust the
2~3mm free
travel
·Put dust cap up and screw jam nut (11) and
adjustment bushing (12) to the upper end
(make the adjustment travel L minimum)
so as to facilitate the assembly of clutch
cable.
·Coat a little lubricant on the assembly
fitting surface of clutch cable.
·Put clip (1) across the guiding cylinder of
clutch pedal on the front brattice to
connect the clutch pedal. Make sure that
washer (3) and end face of guiding
cylinder of clutch pedal are spliced.
·Make butt end (18) fixed by bracket after
across the slot in release arm of
transmission and rubber cushion through
the upper face of transmission.
·After the assembly, uplift the segregation
arm of transmission by hand and adjust the
adjustment bushing (12) down at the same
time, so the 2~3mm clearance for
segregation arm of transmission is
available; then tread the clutch pedal for 10
times to ensure the fitness of assembly and
readjust the adjustment bushing to
guarantee that the 2~3mm clearance for
segregation arm of transmission is
available (Remarks：For new clutch, the
adjustment travel L of driven disk cable
shall not be less than 18mm. See Pic.2).
·Carry out the driving examination for the
whole automobile. Clutch and gear shifting
operation shall be normal.
·Screw jam nut (11) down to close with
adjustment bushing (12), and then put
down dust cover (9).
L (adjustment travel)
Jam nut
Adjust
bushing
down
bushing to a proper position
Rubber cushion
Bracket
Transmission
release pusher
Picture 2 Sketch Map of W
Clutch Adjustment
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CLUTCH DISASSEMBLY
·Disassemble the transmission.
·Unscrew 9 fixed bolts in flywheel
cornerwise and dismount the flywheel.
·Remove clutch plate.
·Pry out snap ring of release disk by
screwdriver and remove the release disk.
·Unscrew 6 connection bolts in clutch
pressure plate and output end of
crankshaft, and remove the clutch pressure
plate.
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CLUTCH OVERHAUL
· Clutch friction disk: measure the dent depth of
rivet head, i.e. the distance between the rivet head
and the friction disk surface. In case it is found that
the depth reaches the using limit for any hole, the
friction disk shall be changed.
Standard value Maintenance
Rivet head
1.5mm
0.5mm
Dent depth
0.06in
0.02in
·Measure the clutch disc runout using a dial indicator.
If the runout is excessive, replace the clutch disc.
Runout 0.8mm max
Clutch pressure plate:
·Examine whether the diaphragm spring has
abnormal wear or damage.
·Examine whether the pressure plate has wear or hot
point.
·In case of any abnormality, the pressure plate shall
be changed. The pressure plate shall not be
disassembled into two parts: diaphragm spring and
pressure plate.
·Measure the clutch pressure plate runout using a dial
indicator. If the runout is excessive, replace the
clutch disc.
Runout 0.25mm max
Flywheel:
·Examine whether the connection surface of friction
disk exists abnormal wear or hot point; the change
or maintenance shall be conducted if necessary.
·Measure the flatness of the flywheel with a straight
edge and a feeler gauge. If not as specified, replace
the clutch cover.
Maximum clearance 0.05mm
Service limit 0.15mm
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CLUTCH INSTALLATION
Before the assembly, flywheel surfaces and pressure
plate shall be clear and dry.
——Assemble the pressure plate on the crankshaft
and screw up bolts in accordance with
prescribed moment.
Pressure plate
assembly bolt
Torque
—— Assemble release disk and fit on snap ring.
—— Assemble clutch disk.
—— Assemble flywheel.
——Screw up flywheel bolt uniformly according to
the diagonal line.
——Coat a thin layer of grease on the input axle
and then assemble the transmission with
engine.
N•m Kg-m 1b-ft
57-65 5.7-6.5 41.5-47.0
Flywheel
bolt
Torque
Remarks:
When put the input axle of transmission into the
clutch friction disk, the flywheel shall be revolved
until the input axle of transmission and spline
meshed.
N•m Kg-m 1b-ft
18-28 1.8-2.8 13.5-20.0
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Trouble
symptom
Slip of clutch
Uncompleted
segregation of
clutch
Vibration of
clutch
Clutch noise
Non-separation of
clutch
TROUBLE DIAGNOSIS
Cause Treatment method
•Free travel (free play) of clutch pedal is wrong.
•Abrasion or oil stain for clutch friction disk.
•Distortion for friction disk 、 pressure plate or
flywheel surface.
•Diaphragm springs become weaker.
•Free travel of clutch pedal is wrong.
•Diaphragm springs become weaker or abrasion for
stabber fingertip.
•Rust for input axle spline.
•Mutilation or abrasion for input axle spline of
transmission.
•Excessive nodding action for clutch friction disk
assembly.
•Abrasion or oil stain for clutch friction disk.
•Brighten of clutch friction disk (to become
glassiness).
•Oil stain for clutch friction disk.
•Bad skid of segregation bearing on the bearing
sleeve of transmission.
•Shimmy of clutch friction disk assembly or bad
connection of friction disk.
•Vibration reduction torsion springs of clutch
friction disk assembly become weaker.
•Loose of rivet of clutch friction disk.
•Distortion of pressure plate or flywheel surface.
•Loose of the binding bolt of flywheel or loose of
binding bolt of pressure plate assembly.
•Abrasion or mutilation for segregation bearing.
•Abrasion for front bearing of input axle.
•Abnormal noise for clutch friction disk.
•Crack for clutch friction disk.
•Abnormal noise for pressure plate and diaphragm
spring.
•Clutch friction disk has fat liquor.
•Serious wear of clutch friction disk.
•Rivet head is displayed in surface of disk.
•Torsion springs become weaker
Adjust free travel
Change friction disk
Change frication disk,
pressure plate or flywheel
Change clutch pressure plate
Adjust free travel
Change pressure plate
Lubricate
Change the input shaft
Change friction disk
Change friction disk
Repair or change friction
disk
Change friction disk
Lubricate
Change friction disk
Change friction disk
Change friction disk
Change pressure plate or
flywheel
Screw down
Change segregation bearing
Change input shaft bearing
Change friction disk
Change friction disk
Change pressure plate
Change friction disk
Change friction disk
Change friction disk
Change friction disk
F-8
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COOLING SYSTEM
DESCRIPTION OF COOLING SYSTEM … … …… …… … …… …… … …… …C-2
COMPONENTS OF 480 ENGINE COOLING SYSTEM … … ……………………C-2
WORKING PRINCIPLE OF COOLING SYSTEM … … …… …… … …………C-2
PARAMETERS OF COOLING SYSTEM … … …… …… … …… …… … …… C-3
ENGINE COOLANT … … …… …… … …… …… … …… …… … …………… …C-3
COOLANT DISCHARGE … … …… …… … …… …… … ………………………C-3
COOLING SYSTEM CLEANING … … …… …… … …… …… … ……… …C-3
COOLANT FILLING … … …… …… … …… …… … …… …… … ……………C-4
COOLING SYSTEM CHECKUP …… …… ……… ……… ……… …… …… …C-5
COOLING SYSTEM MAINTENANCE WARNING … … …… …… … ……… …C-5
WARNING … … ………… ………… ………… ………… …… …… … …… …C-5
WATER PUMP … … …… …… … …… …… … …… … … … ………………………C-6
STRUCTURE … … …… …… … …… …… … …… …… … …… …… … …C-6
DISASSEMBLY/ASSEMBLY … … …… …… … …… …… … …… …… … …C-6
THERMOSTAT … … …… …… … …… …… … …… …… … …… …… … …… …C-7
DISASSEMBLY/ASSEMBLY … … …… …… … …… …… … …… …… … …C-7
WATER TEMPERATURE SENSOR … … …… …… … …… …… … ………… …C-9
DISASSEMBLY/ASSEMBLY … … …… …… … …… …… … …… …… … …C-9
CHECKING … … …… …… … …… …… … …… …… … …… …… … …… C-9
COOLING FAN … … …… …… … …… …… … …… …… … …… …… … …… C-9
DISASSEMBLY/ASSEMBLY … … …… …… … …… …… … …… …… … …C-9
GUIDELINE FOR DISASSEMBLY … … …… …… … …… …… … ……… …C-10
EXPANSION RESERVOIR … … …… …… … …… …… … …… …… … …… …C-11
DISASSEMBLY/ASSEMBLY … … …… …… … …… …… … …… …… … …C-11
ASSEMBLY OF RADIATOR …… …… …… … ……… …… … …… …… … …… C-12
DISASSEMBLY/ASSEMBLY … … …… …… … …… …… … …… …… … …C-12
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COOLING SYSTEM
Hose
Thermostat Chassis and
Hose Hose Hose Hose
Radiato
DESCRIPTION OF COOLING SYSTEM
COMPONENTS OF 480 ENGINE COOLING SYSTEM
Engine cooling system is used to cool engine to
prevent the engine from overheating, ensuring the
normal operation of engine. It is composed of the
timing belt-driven water pump, transverse radiator,
water tank, water pipe, thermostat, temperature control
switch of electrically-driven fan and water temperature
sensor.
WORKING PRINCIPLE OF COOLING SYSTEM
When the temperature of engine coolant is
relatively low, the thermostat shall turn it off, and the
coolant shall circulate and flow among the cylinder
block, water pump and warm air exchanger. This kind
of circulation is called small circulation.
When the temperature of engine coolant is
relatively high, the thermostat shall turn it on, the
coolant shall flow into the radiator, the electrically
-driven fan shall operate to lower down the temperature
of coolant. And then the coolant shall flow back to the
engine cylinder block. This kind of circulation is called
big circulation. As the big circulation operates, the
small circulation shall also play its role.
Warm Air/Heat Exchanger
Engine
Water Pump Inlet
Water Temperature Sensor
Cooling Water Pipe Assembly
Hose Assembly
Electrically-Driven Fan
Pressure Cap
Thermostat Assembly
Hose Assembly
Thermo-Switch
Expansion Tank
As the engine works under normal work
temperature the engine coolant shall expand. Under this
circumstance, the overflow valve installed on the
thermostat chassis shall turn it on, the coolant shall
flow into the expansion water tank through the
overflow pipe; and as the system cools down, the
coolant shall flow back to the water pump inlet from
the expansion reservoir.
The operation of electrically-driven fan is
controlled by the thermo-switch installed on the right
water chamber of radiator. When the contact points of
thermo-switch meet together, the electrically-driven fan
shall run. The water temperature sensor is fitted on the
back of cylinder head lying at the side of exhaust pipe.
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PARAMETER OF COOLING SYSTEM
Cooling system Parameter
Total system capacity（L） 8
Coolant capacity
Fan
Water pump
Radiator
Thermostat
Thermo-switch
Coolant Discharge:
――To demount the pressure cap of expansion
reservoir;
Engine capacity（L） 3.3
Radiator capacity（L） 2.1
Expansion reservoir capacity（L） 0.4
Diameter: 280mm
Number of blades: 6
Operating voltage: 9-15V
Rotating speed Ι gear: high-speed engine 2000±200
Rotating speed II gear: high-speed engine 2800±200
Diameter of impeller: ф72mm
Transmission rate: 1.053:1
Opening pressure of the pressure cap: 160kPa
Front face area: 0.202m²
Heat abstraction area: 8.93m²
Opening temperature: 85º-89º
Full opening temperature: 99º-102º
Switch-on temperature gear95 Cº gear 102 CºⅠⅡ
Switch-off temperature gear≤84 Cº gear≤91 CºⅠⅡ
Operating voltage: 12V
ENGINE COOLANT
low-speed engine 1800±200
low-speed engine 2600±200
――To install a vessel under the radiator, demount
the radiator outlet hose under the radiator and
discharge the coolant.
Cooling System Cleaning:
――To discharge coolant, mount the radiator outlet
hose;
――To inject clean water up to the position of the
largest water surface of the expansion reservoir
from the expansion reservoir filler, and then close
the pressure cap;
――To start up engine to make it operate at idle speed,
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preheat up to normal operating temperature, shut
――To check whether the pipeline is well connected
e cap; fill up coolant into the
expansion reservoir filler slowly. Since the
expansion reservoir is at the highest position in the
herefore, as the coolant level
rises, the air in the system shall be discharged into
and shall be discharged out
of the expansion reservoir by injecting coolant
――To continuously inject coolant up to the highest
nd then close the filler to prevent
――To start up the engine to make it operate at idle
speed and preheat up to normal operating
ns to run,
observe water thermometer and check if the engine
is at overheating condition. If the coolant level in
down and cool down;
――To discharge coolant;
――To repeat the abovC-mentioned steps until the
discharged water is the same as the clean water;
――To clean the cooling system according to the
following methods if the coolant is not correctly
used and replaced to meet the requirements in the
former utilization:
a. To discharge coolant;
b. To demount the radiator inlet hose, insert the main
water hose into the radiator filler until the outlet
water becomes clean;
c. In order to flush out the engine, you should connect
the main water hose with the water outlet of the
thermostat to clean the engine until the discharged
water flowing from the water pump inlet becomes
clean;
d. To repeat cleaning operations if the radiator is very
dirty, and connect the main water hose with the
radiator water outlet until the water flowing from
the radiator water outlet becomes clean.
Coolant Filling:
and fastened before injecting coolant;
――To open the pressur
cooling system. T
the expansion reservoir
slowly.
coolant level. A
coolant from spilling.
temperature. And until the fan begi
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the expansion reservoir descends quickly, coolant
should be injected up to the highest position to cut
down the air circulation in the system.
if
――To open the pressure cap to check the coolant level, and
vel, start up the engine and
preheat it. Put the engine under idle speed
circumstance until the cooling fan runs, and check
if coolant leakage exists at various pipe joints. Shut
down the engine and wait for engine cooling. And
vel in the expansion
――To try best to prevent the coolant spilling from
――To shut the engine down to have it fully cooled（
possible, leave the engine alone for one night.）;
inject coolant up to the highest position.
Cooling System Checkup:
――To check the coolant le
then check if the coolant le
reservoir is at normal condition.
scalding operator during checkup.
――To timely check if water flows into the engine oil
pan (the lubricating oil shall become milk white
after water flows) when no pipe leakage is found
and the expansion reservoir is short of coolant, and
timely stop water from flowing in when finding it.
COOLING SYSTEM MAINTENANCE WARNING
Warning:
·To try best not to move radiator cap or loose the radiator discharging plug when the engine
is under operation or the engine and radiator are at a very high temperature. Scorching
coolant may spill out, hurting the people and damaging the engine and cooling system.
·To shut down the engine until it cools down, and then carefully demount the radiator cap.
Meanwhile, wrap a large thick cloth onto the radiator cap, rotate it slowly to the position
of the first clip along the counter-clockwise direction and then release the pressure slowly.
·To use a cloth to push down the radiator cap, rotate and remove the radiator cap after the
operator ensures all the intensity of pressure has been released.
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WATER PUMP
Structure:
To discharge engine coolant (refer to the coolant
4 bolts out of the front side of
To install the water pump assembly in the cylinder
block and screw up 4 fixing bolts by hand, and
The water pump impeller installed in the cylinder
Note: Because water pump assembly can not be
seal ring or bearing
Tightening Torque
Gasket
1—Water pump housing
2—Water pump impeller
3—Water pump gear
4—Water pump shaft bearing
5—Water pump seal (ceramics-lead)
Disassembly:
——To disconnect the negative terminal of battery;
——
discharge process);
——To disconnect poly V-belt and power pump belt;
——To demount timing shield;
——To unscrew and take
cylinder block.
——To demount the water pump assembly;
——To demount the water pump gasket.
Assembly:
——To install the new gasket on the water pump;
——
then screw up to 7.0—10.0Nm;
——
block should be able to rotate freely;
——To refill engine coolant;
——To check leakage occurrences of engine coolant.
repaired, it should be replaced when
is worn and torn.
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THERMOSTAT
To unscrew 3 M6×40 bolts and then demount the
To demount thermostat chassis and thermostat
To pry out the spring clamps by using chisel or
Disassembly:
——
bolts;
——
assembly.
——
screwdriver.
——To take the thermostat out;
——To clean up the thermostat;
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——To take the seal ring
out, and replace it if it being
To demount the gasket from the thermostat chassis.
To measure the thermostat opening temperature
worn and torn.
——
（To replace with new gasket if it is worn and
torn, and allow no repeated use.）
——
under hot water.
Assembly:
——To clamp the thermostat and then put the gasket
into the thermostat aperture.
——To install thermostat (the side with spring facing
outward).
——To embed spring clamp to ensure the clip within
the thermostat chassis slot;
——To mount new gasket onto thermostat chassis;
——To mount the thermostat chassis and thermostat
assembly into the aperture at the rear side of engine
cylinder head, and screw up the bolt by hand to
9—12N.m.
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WATER TEMPERATURE SENSOR
Disassembly:
——To demount water temperature sensor (at the
exhaust pipe flank and under the lifting eye).
Assembly:
——To apply Letai 243 glue on the screw thread,
screw up the bolt to 7.0—10.0Nm before
installation.
Checking:
Water temperature sensor is a negative temperature coefficient sensor, which is composed of
a thermal resistor. The resistance value of the resistor shall decrease as the engine temperature
rises. The variation is detailed in the following table:
Temperature (°C) Resistance Value (Ω)
-20 29,125
-10 16,660
0 9,790
+20 3,748
+25 3,000
+60 747
+80 377
+100 204
+120 117
COOLING FAN
Disassembly:
——To disconnect the negative terminal of battery;
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——To demount the matching plug of the cooling fan.
tapping screw from
p the engine and check if the cooling fan
During the disassembly process, you should pay
more attention not to pull A/C pipe to a large extent,
——To remove the fastening self-
the cooling fan.
——To take the cooling fan out.
Assembly:
——To assemble the cooling fan according to the
disassembly order (the tightening torque of
self-tapping screw is 1.8~2.2Nm)
——To start u
is under normal operation.
Guideline For Disassembly:
——
otherwise the A/C pipe shall crack and deform.
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EXPANSION RESERVOIR
Disassembly:
——To demount the water pipe connecting with the
expansion reservoir.
——To pry out the protecting hood of expansion
reservoir by using a screw drive.
——To demount the fastening bolts of the expansion
reservoir by using M10 sleeve.
——To pull out the plug of liquid level sensor.
——To take the expansion reservoir out.
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To demount the left and right wind boards by M10
Assembly:
——To assemble the expansion reservoir according to
the order opposite to the disassembly order（the
tightening torque of self-tapping screw is
4.0~5.0Nm）.
——To refill coolant.
ASSEMBLY OF RADIATOR
Disassembly:
——To discharge coolant (refer to the coolant discharge
process)
——To demount the cooling fan (refer to the
disassembly process of the cooling fan).
——
sleeve.
——To take out the radiator.
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——To take out the radiator
Assembly:
——To assemble the radiator according to the order
opposite of the disassembly order.
——To install the 2 wind boards onto the radiator by
using self-tapping screws with their tightening
torque of 6～7Nm.
——To install the radiator onto the front transom and
put it straightly towards the positioning hole.
——To install the left and right tensioned plates of the
radiator, and tighten the bolts of the plates with
tightening torque of 5±1Nm.
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ENGINE ELECTRONIC SYSTEM
INPUT / OUTPUT COMPONENTS OF CONTROL SYSTEM … …… … … … …E-2
WORKING MODULE TABLE OF FUEL INJECTION / IGNITION SYSTEM …E-3
WORKING PRINCIPLE … …… … … … …… …… … … … …… …… … …E-4
ELECTRICAL CONTROL UNIT …… …… … … … …… …… … …………E-5
WORKING PRINCIPLE OF ELECTRONIC FUEL INJECTION CONTROL AND
ACTUATORS …………………………………………………………………………E-7
BASIC PRINCIPLE OF MALFUNCTION DIAGNOSIS FOR ELECTRONIC FUEL
INJECTION SYSTEM ………………………………………………………………E-21
DETAILED TABLE OF MALFUNTION DIAGNOSTIC CODE …………………E-24
PROCEDURES FOR FAULT DIAGNOSIS ACCORDING TO THE SYMPTOMS OF
THE ENGINE …… …… …… … …… …… …… …… …… …… …… ……E-62
SAFETY PRECAUTIONS OF SYSTEM MAINTENANCE ………………………E-88
SAFETY PRE CAUT IONS IN DI AGOSIS AND M AINTENANCE OF T HE
GASOLINE INJECTION ELECTRONIC CONTROL SYSTEM …………………E-88
SAFETY MEASURES ……………………………………………………………E-89
E-1
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INPUT / OUTPUT COMPONENTS OF CONTROL SYSTEM
19
18
Diagnostic
connector
1 Engine ECU 11 Fuel injector
2 Air pressure / temperature sensor 12 Oxygen sensor (heater)
3 Engine speed sensor for top dead center 13 Fuel pump
4 Throttle valve position sensor 14 Carbon canister solenoid valve
5 Knock sensor 15 Two step speed fan controller
6 Coolant temperature sensor 16 Compressor relay control
7
Oxygen sensor (λ signal)
17 Idling speed step motor
8 Air condition request 18 Diagnostic connection
9 Ignition coil and spark plugs 19 Relay
10 Instrument panel
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WORKING MODULE TABLE FOR FUEL INJECTION / IGNITION
Fuel pump
A/C relay
Fuel injector
Carbon canister
Throttle valve
position sensor
Air pressure /
Power supply
Cooling temperature
SYSTEM
Power supply relay
(Power supply +12V)
Power supply
(15/54)
Idling speed step motor
Malfunction
indicator
Ignition coil
ENGINE
Engine
solenoid valve
Coolant temperature sensor
Line K
temperature sensor
Knock sensor
·
overheat alarm light
·Decoder alarm light
TDC/rotate speed sensor
Oxygen sensor heater
Heated Oxygen sensor heater
·R.P.M. meter
Fan relay
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WORKING PRINCIPLE
This system is capable of controlling the actual tested air-fuel ratio under all engine speeds to
stay close to the equivalent proportion of the chemical reaction, so as to protect the catalyst
package and subsequently reduce the discharge of pollution. The oxygen sensor analyses the
oxygen content of the discharge gas using real-time principle and makes it possible for the
ECU to control the amount of injecting fuel to correct the air-fuel ratio. The fuel with a
pressure of about 3.5 bars is directly injected into the air intake manifold near the throttle
valve.
The fuel injectors of all cylinders are utilizing a sequential phase angle control method
according to the intake sequence and the opening time of the air intake valves; the injection
destinations are stored in the ECU map, and can vary autonomously according to the engine
speeds and intake air pressures. The application of sensors in the system is a basic strategy
used to correct the engine under all operating conditions. The system is implementing an
induction type of electrical discharge ignition, where the power source module in the ECU
controls the ignition timing. The ignition advance angle is calculated according to the engine
compression ratio and intake air volume. The idling speed is maintained at stable condition
through controlling the opening of the branch-connection pipe by a step motor and also
through the changing of the ignition points.
Other than capable of obtaining the input signals and controlling the output components, the
system has also equipped with various other functions. These functions include the following:
- When self-diagnose that the sensor is faulty, adopt the restoration strategic control.
- Restoration of the self-regulating mixed concentration engine and variances in spare parts.
- Exchange data with the diagnostic tester.
The idling speed of the engine and the amount of CO in the air discharged must not be
manually adjusted.
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ELECTRONIC CONTROL UNIT
The ECU is located on the left of engine firewall. The ECU handles various signals from the
sensors and controls the actuator so as to achieve the best possible operating condition. Many
extra functions are added as compared with the previous model. While by the usage of a
custom-made circuit board that can achieve many special functions, the integrated functions
are enhanced so that the structure has considerably reduced in size and become much more
compact.
The hard wares in the ECU are as follows:
-16 bit CPU single chip
- 8KB RAM (2KB IRAM + 6KB ERAM)
- 2MB FLASH EPROM (12V programming voltage)
- 2KB SERIAL EEPROM
- 16 CHANNELS 10 MODULES/NO. (A/D) CONVERTER
- 4PWM OUTPUT
- CAN MODULE (CAN2.0B)
The ECU software structure is divided into two parts for data processing:
-The “Application” part obtained the measurement of engineering parameter through sensors
to calculate the control parameters of the fuel injectors, ignition coils and idling speed step
motor for controlling the engine starting.
-The “Basic” part is collecting the data from the sensors and converts it into engineering data.
After that it controls the actuator through the calculated parameter generated by the
“application” software, and manages the self-diagnostic programs of the various sensors and
actuators. In addition, it can also communicate with the externally connected diagnostic
tester through the use of “K” serial cable.
The operating system is capable of ensuring the accurate management of the matters related
with time (such as the management of definite and delay timing) and angles (related to the
engine rotation sequence). This type of management is integrated in the software and
calculated according to the precise priority to ensure the optimization management of the
engine even at its high-speed condition. This type of “modular structure” design allows the
possibility of achieving all kinds of flexibility control and in the mean time not tampering the
overall characteristic of the system.
The following data are transmitted into the ECU:
- Battery voltage
- Absolute pressure sensor in the air intake manifold
- Top dead center
- Throttle valve opening angle position
- Air intake temperature
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- Engine coolant temperature
- Air conditioning operation
- Signal from oxygen sensor
- Knock sensor for the accelerator meter on top of the engine crankshaft housing
The air intake efficiency is obtained by calculating through the processing of absolute
pressure, air intake temperature, engine speed, throttle valve position and other signals, and
help to determine the air intake quantity of the cylinder. The inbuilt power supply module in
the ECU is controlling the following functions:
- To control the injected fuel quantity through the control of opening timing of the fuel
injector
- Idling speed step motor
- Ignition coils of the 4 high voltage outputs
- Check valve for recirculation the gaseous fuel on top of the air intake manifold (carbon
canister)
- Temporary turnoff of the air condition compressor
- Dual speed cooling fan for the engine
- Overheating alarm light in the coolant of the engine
- Malfunction alarm light
Other than these major functions, ECU also controls:
- All the self-diagnostic strategy related to input sensors and output actuators
- Wrong signals restoration strategy works on basically effective input signals
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WORKING PRINCIPLE OF ELECTRONIC FUEL INJECTION
Manif
old absolute
pressure and intake air
temperature sensor
CONTROL AND ACTUATORS
※ Intake Pressure and Intake Air Temperature
Sensor
Purpose: detects manifold absolute pressure from
0.1~0.2bar and intake air temperature, provides engine
with load information.
Composition and principle: this sensor is composed
of two different sensors (i.e. manifold absolute
pressure sensor and intake temperature sensor), and is
installed above pressurizer.
Pressure-sensitive element inside intake pressure
sensor detects pressure signal on intake manifold for
injection pulse width control of EFI system. This
sensor also serves as the substitute of load signal
sensor.
Intake air temperature sensing element is a resistor
of negative temperature coefficient (NTC), which is
similar to water temperature sensor with resistance
value decreasing with the increasing of intake air
temperature. And engine ECU monitors the variation
of intake air temperature via a comparison circuit
inside.
TMAP
Failure diagnosis: The electronic device next to
intake pressure sensor detects sensor circuit troubles
such as open circuit, short circuit and sensor damages,
etc. In case ECU detects any sensor output signal that
goes beyond output characteristic curve, the sensor is
diagnosed as failed by ECU. For example: when
intake pressure is higher than upper limit or lower than
lower limit, ECU detects sensor failure (in case that
intake pressure is lower than lower limit when starting,
ECU is able to recognize the starting condition), and
the engine fault indicating lamp goes on. Under this
condition the engine works in failure mode.
Installation: to be installed on pressurizer.
Circuit diagram of manifold absolute
pressure and intake air temperature sensor
Pins:
1# is grounded (connecting ECU 17#);
2# outputs temperature signal
(connecting ECU 40#);
3# connects with standard 5V power
source (connecting ECU 33#);
4# outputs pressure signal (connecting
ECU 37#).
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Troubleshooting: mainly check if there is short circuit
1 Seal ring
5 Ca
sing
Failure diagnosis:
or open circuit on the connection between 4 lines on
sensor and ECU.
If there is short circuit, open circuit or grounding
between sensor wire harnesses.
Sectional view of intake pressure and
intake air temperature sensor
2Stainless steel bushing 6 Pressure bracket
3 PCB 7 Welded joint
4 Sensing element 8 Bonded joint
※Throttle Position Sensor
Purpose: this sensor is designed to provide ECU with
information of throttle angle. As per such information,
ECU obtains engine load information and operating
mode information (for instance: start-up, idle speed,
reverse, part load and full load) as well as acceleration
and deceleration information. This sensor is three-wire
style, and the throttle opening can be detected by ECU
via monitoring voltage variation.
Composition and principle: Consisting of two
compass sliding contact resistors and two sliding
contact arms, throttle position sensor is an angle
sensor that outputs linear signals. The axes of contact
arms are on the same axial line with throttle axis, with
5V power supply voltage US being applied to both
ends of each contact resistor. When throttle turns,
contact arms turn along with it and move on sliding
contact resisters, educing potential of contacts UP as
output voltage. This sensor is actually an angle
potentiometer.
Throttle Position Sensor
ECU monitors throttle angle, and
detects sensor failure when output signal exceeds
upper or lower limit, in which case engine will work in
failure mode, and fault indicating lamp will go on.
Installation: allowable tightening torque for fastening
screw is 1.5Nm-2.5Nm.
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Circuit diagram of throttle position sensor
Pins:
1 sensor signal ground (ECU17#)
2 5V power (ECU32#)
3 sensor signal (ECU16#)
Troubleshooting: mainly check if there is short circuit
or open circuit on the connection between 3 lines on
sensor and ECU.
Check to see if there is short circuit, open circuit or
grounding between sensor wire harnesses.
※Coolant Temperature Sensor TF-W
Purpose: this sensor is designed to provide coolant
temperature information. To provide engine ECU with
water temperature signal used for control of ignition
timing and fuel injection pulse width in startup, idle
speed and normal operation.
Composition and principle: this sensor is a
thermistor of negative temperature coefficient (NTC)
with resistance value decreasing with the increasing of
coolant temperature except linear relation. The said
thermistor is installed in a heat-conducting sleeve.
ECU monitors water temperature variation by
converting resistance value of thermistor into a
changing voltage through a bleeder circuit (inner
structure of ECU).
Failure diagnosis: When coolant temperature is
higher than allowed upper limit or lower than lower
limit, failure mark of the knock sensor is set, engine
fault indicating lamp goes on and engine works in
failure mode. In this case ECU controls ignition and
fuel injection according to set water temperature for
failure mode, at the same time the fan is running at
high-speed mode.
Coolant Temperature Sensor
Limiting data: 2.5±5%KΩ
Installation hint: tightening torque is 15Nm in
maximum.
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Circuit diagram of Coolant
temperature sensor
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