FUEL PUMP CONTROL [SKYACTIV-G 2.5T]
id0140h0004100
Outline
• The PCM accurately controls the fuel pump discharge amount and fuel pressure while monitoring the fuel temperature/fuel pressure between the fuel pump unit and the high pressure fuel pump according to the engine operation conditions and the environment conditions to optimize power consumption by the fuel pump and improve fuel economy.
Block Diagram
Operation
Fuel pump relay
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• The PCM switches the fuel pump relay on/off according to the engine operation conditions.
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Relay ON/OFF
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Control conditions
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ON
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• When any of the following conditions is met:
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― When ignition is switched ON (for approx. 1 s)
― During engine cranking
― While engine is running
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OFF
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• When engine is stopped
• Immobilizer system related information (engine start prohibited) received from start stop unit
• Collision signal from SAS control module is received
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Fuel pump control module
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• The PCM calculates the fuel pump discharge amount and fuel pressure according to the engine operation conditions and environment conditions and determines the applied voltage to the fuel pump. The PCM sends a duty signal to the fuel pump control module according to the applied voltage.
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Output duty ratio
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Control conditions
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95 %
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• When any of the following conditions is met:
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― At engine start
― Fuel pump control module malfunction (if request voltage is unobtainable)
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10—90 %
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• Except for control conditions with output duty ratio of 5 % or 95 %
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Fuel pump operation circuit diagram
