Maintenance manual for sunray hfc4da1-2c china-IV diesel engines
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Section IV Electronic Control Unit of High Pressure Common Rail System
The EDC17 system of HFC4DA1-2C engine belongs to electronically controlled diesel injection system and
incorporates the dynamic fuel injection timing system and air and fuel management system. It adopts the BOSCH
diesel high pressure common rail system, with the rail pressure up to 1,600bar, and applies new technologies
including VNT, electronically controlled EGR, and POC pressure difference control to meet the Euro-IV emission
standard, with potential compliance for Euro-V emission standard.
The characteristics of this system is one single ECU, one set of fuel injection control system, and one set of sensor
system. It’s functioned to inject the fuel into the engine cylinder, with accurate injection timing and fuel amount, so
that the fuel is mixed with air in the cylinder to achieve best combustion efficiency.
The electronic control unit of the diesel common rail system is mainly composed of three parts: sensor, ECU, and
actuator.
① Sensor part: The sensors and rated value transmitters collecting the running state and rated values of the engine
and complete vehicle, which convert various types of physical parameters into electric signals.
② ECU: It’s functioned to process the information as per definite mathematic calculation method and issue the
electric signals of the directives.
③ Actuator: It’s functioned to convert the electric signals of the directives issued by the ECU into mechanical
parameters.
I. Sensor part
1. Crankshaft position sensor
1) Overview
z The crankshaft position sensor is one electromagnetic sensor.
z The position of piston in the combustion chamber determines
the start moment of fuel injection. As the engine piston is
connected with crankshaft through connecting rod, the
crankshaft position sensor can provide all data information for
the piston position and the engine speed determines the
revolution per minute of the crankshaft.
z Generation of signal: The crankshaft is connected with one
60-tooth ferromagnetic actuation gear. The actuation gear
actually in use has two teeth missing. This large gap
corresponds to one specified crankshaft position of 1
st
cylinder.
The crankshaft position sensor records the tooth sequence of
the actuation gear. It’s composed of one permanent magnet and
soft iron core with copper coil. The magnetic flux in the sensor
varies along with the gear and gap passing through and
generates one sine AC voltage, of which the amplitude rapidly
increases following the speed of the engine (crankshaft). It can
achieve sufficient amplitude even when the speed is at 50r/min.
z The crankshaft position sensor is situated on the rear clutch
housing of the engine;
z Wiring terminals: 1. Signal terminal of crankshaft position
sensor; 2. Grounding terminal of crankshaft position sensor;
Crankshaft speed sensor
1. Permanent magnet 2. Sensor housing
3. Engine outer cap 4. Soft iron core
5. Coil 6. Sensing gear
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