Maintenance manual for sunray hfc4da1-2c china-IV diesel engines
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Use diagnosis instrument to check the trouble code and determine the
malfunction position. Mainly check whether the sensor is installed in place and
whether the clearance is normal, check the sensor circuit whether there is
short-circuit or open-circuit to grounding wire, check whether there is
short-circuit or open-circuit to the power supply, and check whether the circuit
is consistent with the given pin definition.
Notice: Take caution to install the sensor and make sure not to add any washer,
or it may lead to signal distortion of sensor.
2. Camshaft position sensor
1) Overview
z The camshaft position sensor is one Hall sensor.
z The camshaft position sensor utilizes the Hall effect to determine the camshaft position. One steel actuation gear
rotates along with the camshaft, the Hall effect integrated circuit is installed between actuation gear and
permanent magnet, and the permanent magnet generates a magnetic field perpendicular to the Hall unit. If one
tooth of actuation gear passes through the current-carrying linear sensor unit (semiconductor chip), it changes the
strength of magnetic field perpendicular to the Hall unit. In such case, the electron driven by the voltage in major
axis direction is offset in the direction perpendicular to the current direction to generate one temporary signal
voltage (Hall voltage) so that the calculation circuit integrated with the sensor Hall integrated circuit will process
the signal and output as square wave signal.
z The camshaft position sensor is installed on the cylinder head shield.
z Wiring terminals: 1. +5V power supply, 2. Signal output, 3. Grounding;
z The clearance between sensing end of sensor and the signal gear of camshaft: 0.5~1.5mm. Required torque:
8±0.5Nm
2) Working Principle
The camshaft controls the intake and exhaust valves of the engine, of which the speed is only half of the crankshaft
speed. When the piston moves towards the top dead center, the camshaft position determines whether the piston is at
compression stroke or the exhaust stroke and then judges the fuel injection or not. If the engine is under start stage,
such data information can’t be acquired from the crankshaft position. On the other hand, during the normal working
of the engine, the data information generated by the crankshaft sensor is enough to determine the engine state. In
other words, while the vehicle is traveling, even the camshaft sensor is failed, the ECU can still receive the data
information of engine working state from the crankshaft sensor.
The camshaft sensor utilizes Hall effect to determine the camshaft position. One steel toothed part is fixed on the
camshaft and rotates along with the camshaft. When this toothed part passes through the semiconductor chip of the
camshaft sensor, its magnetic field will offset the electron of the semiconductor chip towards the current direction.
Therefore, one temporary voltage signal (Hall voltage) is generated to remind ECU that the 1
st
cylinder enters into the
compression stroke.
3) Measurement analysis
Wiring terminals: 1 - +5V, 2 – Signal +, 3 – Grounding
Camshaft
position
sensor
Grounding terminal
Signal terminal
Power supply terminal
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