Shock Sensor - Lifan 620 Maintenance Manual

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(1) Function: To provide information on coolant temperature. To provide water temperature signal
for the ECU, and to control ignition timing and fuel injection pulse width at start, idle speed, and
normal operation.
(2) Structure and principle: Made by a thermistance with NTC. The resistance value will
decrease with the increase of the coolant temperature (not a linear relation). The thermistance
with NTC is installed within a copper sleeve. With a voltage division circuit, the resistance value of
the thermistance is converted into a changing voltage and then provided to the ECU, and then the
change of water temperature can be monitored (internal structure of ECU).
(3) Connection of wiring diagram (Fig. 1-6)
Fig. 1-6
(4) Trouble diagnosis: When the coolant temperature is higher than its upper limit, or lower than
its bottom limit, the engine MIL will be lighted and the engine operation under trouble mode will be
applied. Then, the ECU will carry out the ignition and fuel injection control as per the water
temperature set under the engine water temperature trouble mode, and make the fan run at a high
speed at the same time.
(5) Limit data: 2.5±5%KΩ
(6) Installation note: Tightening torque is 15±2N·m.
4. Shock sensor Fig. KS1-7
KS1-7
(1) Function: To provide engine knock information for the ECU for knock control.
(2) Structure and principle: As a vibration acceleration sensor, installed on the cylinder block of
the engine. The sense element of the sensor is a piezoelectric element. The vibration of the
cylinder block of the engine can be transferred to the piezoelectric crystal through the mass block
within the sensor. Under the mass block vibration pressure, voltage will be produced at the two
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