Maintenance manual for sunray hfc4da1-2c china-IV diesel engines
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helical metal wire embedded within the magnesium oxide powder (Figure). This helical metal wire is composed of
two resistors in series connection and one heating oil and one control coil are installed on the tip of the heating tube.
The heating coil maintains one resistance almost irrelevant to the temperature and the control coil is made of positive
temperature coefficient (PTC) material. In the new generation heating plug (GSK2), the rise amplitude in the
resistance of control coil is larger than common electric heating plug. With capability of rapidly reaching the
temperature required for ignition (up to 850ºC within 4s) and relatively low constant temperature, new electric heating
plug GSK features outstanding performance. Therefore, the temperature of the electric heating plug is restrained at
one critical value. Therefore, after the start of the engine, the GSKZ electric heating plug can continue to maintain
electrified for 3min. This after-combustion performance improves the noise and exhaust emission of start and
warm-up stages.
The control instrument of the electric heating plug adopts one power relay and the electric switch set to control the
electric heating plug, which control the heating time of electric heating plug and feature the protection and monitoring
functions. Thanks to its diagnosis function, higher grade of electric heating plug control instrument can identify the
malfunction of single electric heating plug and display to the driver. The control input terminal of the electric heating
plug control instrument is connected to the electronic control unit (ECU) via multi-pole plug. To prevent the voltage
drop, the series connection circuit connected to the electric heating plug adopts the threaded pin or connector.
The controlled preheating process and the start process are controlled by the electric heating plug starter switch. The
preheating process is started when the key is turned to “ON” position. When the heating control lamp goes out, the
electric heating plug reaches sufficient temperature and the start process can be conducted. In the subsequent start
process, the fuel drips injected will be atomized and get combusted in the compressed hot air so that the heat released
starts the combustion process.
The after-heating after the successful start can help the warm-up process to form one speed promotion and idle run
with no interruption and little smoke. This can reduce the combustion noise at the cold start. In event of
non-successful start, the protection circuit of the electric heating plug is turned off to prevent the excessive discharge
of the battery.
3) Measurement analysis
4) Malfunction Mode:
Short-circuit or open-circuit of preheating control unit;
Damage of preheating control unit;
5) Troubleshooting:
Use special diagnosis instrument to check the trouble code and determine the malfunction position. Mainly check the
circuit of preheating control unit and determine whether there is short-circuit or open-circuit between circuit and the
grounding wire, whether there is short-circuit or open-circuit to power supply, and whether the circuit is consistent
with the given pin definition.
To preheating
plug
Preheating time feedback
Preheating control unit
Preheating relay
Fuse 5
Power supply
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