Chery QQ6 (S21) / S12LHD. Manual — part 200

2.3 Parameters of technical features

Value

Item

Min.

Typical

Max.

Unit

Resistance under a room temperature of

20°

C

774

860

946

W

Inductance

310

370

430

mH

Output voltage at a crankshaft

revolution of 416rpm

>1650

mV

2.4 Installation attentions:
l For the inductive tachogenerator, it is permitted to take out from its pack before it is assembled

to the auto or testing device right away.

l Inductive tachogenerator is assembled by press in method but not hammer tapping.
l Partly micro-encapsulated bolt M6´12 for fixing of the inductive engine tachogenerator is

recommended.

l The tightening torque is 8±2Nm.
l Gas clearance between inductive tachogenerator and pulse disc tip is 0.8-1.2mm.

Dimension d (see the figure below): 4.7mm.

2.5 Failure effects and judgment method:

l

Failure effects: start failure etc.

l General cause of the failure: man induced failure.
l Maintenance precautions: during maintenance, the tachogenerator should be installed by using

press-in method instead of hammering method.

l Simple measurement method:

1. With the joint removed, turn the digital multimeter to Ohm shift, and then connect the two

meter pens respectively to 2# and 3# pins; At 20

, the rated resistance should be 860Ω±10%.

℃

2. With the joint connected, turn the digital multimeter to AC Voltage shift, and then connect the

two meter pens respectively to 2# and 3# pins of the sensor; start the engine and voltage output

should be present at this point. (Inspection with vehicle oscilloscope is recommended).

Oscillogram in Test

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3. Phase Sensor

3.1 Function of the sensor:

Provide ECU with phase signal, i.e. help crankshaft position sensor of engine to judge it is then

at compressing top dead center or air exhaust top dead center.

3.2 Principle of the sensor:

The phase sensor is consisted of the Hall generator installed on the valve cover and the signal

wheel machined on the intake camshaft. When the camshaft rotates, the signal wheel will make the

magnetic flux passing the Hall generator change, thus generating a variable Hall signal.

3.3 Effects and judgment method:
l Failure effects: over proof emission and fuel consumption rise etc.
l General cause of the failure: man induced failure.
l Simple measurement method:

(connect the joint) switch on ignition switch but do not start the engine; put digital multimeter on DC

volt shift, connect two meter pen to No. 1 and No. 3 sensor connectors and make sure there is 12V

reference voltage. Start the engine, check if it is in good conditions of No.2 pin by oscillograph on

vehicle.

4. Water Temperature Sensor

4.1 Function of the sensor:

The water temperature sensor simultaneously provides ECU and instruments with water

temperature signal. ECU will calculate and regulate injection pulse-width and ignition advance angle

through water temperature signal. In addition, through water temperature signal, ECU also can

control turn-on and turn-off of cooling fan to prevent engine from damage caused by overheat.

4.2 Principle of the sensor:

The water temperature sensor is a minus temperature coefficient type electric resistance model

sensor; the higher the temperature is, the less the resistance will be. But, temperature rise and

resistance fall are not in linear relation.

Ground site

Phase sensor

87# pin of main relay

4.3 Parameters of technical features

(1) Data limit

Item

Value

Unit

Rated voltage

Can only be run by ECU

Rated resistance at 20℃

2.5±5%

kW

Range of running temperature

-30 to +130

℃

Max. measuring current passing the

sensor

1

mA

Permissible vibration acceleration

600

m/s

2

4.4 Installation attentions

Coolant temperature sensor is installed on the cylinder body and the copper heat conducted

socket is inserted into coolant. There are thread on the socket, and screw in coolant temperature

sensor onto the threaded hole on cylinder block by the hexagon head of the socket. The maximum

permissible tightening torque is 15Nm.

4.5 Failure effects and judgment method
l Failure effects: starting difficulties etc.
l General cause of the failure: man induced failure.

l

Simple measurement method:

With the joint removed, turn the digital multimeter to Ohm shift, and then connect the two

meter pens respectively to 1# and 2# pins of the sensor; At 20

, the rated resistance should be

℃

2.5kΩ±5% and the others can be measured out from the characteristic curve in above chart.

Analogue method can also be used when measuring, i.e., dip the working area of the sensor in boiled

water (dip for adequate time), observe the resistance change of the sensor, at this point, the resistance

should fall to 300Ω-400Ω(the actual value depends on the temperature of the boiled water).

Coolant temperature
sensor

5. Knock Sensor

5.1 Function of the sensor:

The knock sensor provides ECU with knock signal. When the engine generates knock, ECU

will control to gradually reduce ignition advance angle to eliminate the knock; when no knock

occurs during certain strokes, ECU will gradually increase ignition advance angle to enable the

engine to obtain max. torque.

5.2 Principle of the sensor:

Knock sensor is a kind of vibrating acceleration sensor and is assembled on cylinder block.

Either single or multiple can be installed. The sense organ of the sensor is a piezoelectric element.

The vibration of cylinder block is transferred to piezoelectric crystal by mass block inside of sensor.

The piezoelectricity crystalloid gets pressure from mass block vibration, producing voltage on two

polar and transferring vibration signals to voltage signal and output it. See the following frequency

response characteristic curve. Because the frequency of knock vibration signal is much higher than

the normal engine vibration signal, the ECU can separate the signal into knock signal and non-knock

signal.

5.3 Attentions

Knock sensor has a hole in the middle, through which it is fastened on the cylinder by a M8 bolt.

For the aluminum alloy block, using long bolt with 30 mm; for the casting iron, using 25mm bolt.

The tightening torque is 20±5Nm. The installation position should ensure that the sensor is liable to

receive vibration signals from all cylinders. Decide the optimal installation position of knock sensor

through modal analysis to the engine body. Generally, for a 4-cylinder engine, the knock sensor is

installed between 2# cylinder and 3# cylinder; for a 3-cylinder engine, it is installed at the center of

2# cylinder. Do not let liquid such as engine oil, coolant, brake fluid and water etc. contact the sensor

long. Use of gasket of any type is not allowed in installation. The sensor must cling to the cylinder

tightly through its metal surface. During wiring of sensor signal cables, do not make the signal

cables resonate; otherwise, they may break. Be sure to prevent turning on of high voltage between 1#

and 2# pins of the sensor; otherwise, damage to the piezoelectric element may occur.

5.4 Effects and judgment method

Failure effects: poor acceleration etc.
l Reasons for general failures: long time contact of liquid such as engine oil, coolant, brake fluid

and water etc. with the sensor, which may corrode the sensor.

l Maintenance precautions: (see installation attentions)
l Simple measurement method: (remove the joint) put digital multimeter at ohm shift, and contact

the No. 1, No. 2 and No. 3 pin with its two meter pens. The resistance value should be more

than 1MΩ¸ under normal temperature. Leave the digital multimeter at millivolt shift, and tap

around the sensor using little hammer, there should be voltage signal output.

6. Electric Throttle Body

6.1 Function: