ELECTRIC WATER PUMP CONTROL
id304000201100
Outline
• During operation, the high voltage parts of the EV system generate heat due to high voltage charging and discharging and become hot. For this reason, the PCM maintains the appropriate operating temperature for the high voltage parts by driving the electric water pump to circulate coolant to the high voltage parts.
• The PCM sends the electric water pump drive signal via LIN communication. Additionally, it monitors the electric water pump operation status by receiving the operation status signal from the electric water pump.
Block Diagram
Operation
Coolant temperature conditions
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During READY on:
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• The PCM controls the output duty ratio according to the coolant temperature so that the EV system component parts do not exceed the temperature for correct operation.
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During READY off:
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• When the user charges the high voltage battery externally and the climate control timer control is operated, the PCM controls the output duty ratio according to the coolant temperature so that the EV system component parts do not exceed the temperature for correct operation.
High-voltage part temperature conditions
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• If the temperature of a high voltage part is high, the PCM operates the electric water pump at maximum speed (99% duty ratio) until the temperature decreases to the appropriate temperature for part protection and assuring drivability.
• If CAN communication with other modules is cut, the PCM cannot detect high voltage part temperatures. To assure part protection and drivability, the PCM operates the cooling fan at a duty ratio of 90%.
• If the electric motor temperature is higher than the specified value after READY off, the PCM operates the cooling fan at 90% duty ratio until the temperature decreases to the appropriate temperature for preventing deterioration of the stator coil winding insulation.
Air bleeding mode
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• When replacing the coolant or the parts that circulate the coolant, it is necessary to bleed the air accumulated in the coolant passage to assure cooling performance. The PCM operates the electric water pump regardless of the coolant temperature by a determined combination of accelerator pedal and brake pedal operations.
• The PCM stops air bleeding mode when it detects any of the following conditions.
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― Air bleeding mode has operated for 15 min
― Main power is other than ON (READY off)
― Shift position is other than P position
Fail-safe operation
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• If the PCM detects that the electric water pump is left operating empty, it detects DTC P2B2A:00 and stops the electric water pump to prevent damage.
