ELECTRICAL FAN CONTROL [SKYACTIV-G 1.3, SKYACTIV-G 1.5]
id0140q1205000
Outline
• Through cooling of the radiator and condenser by operation of the cooling fan (according to vehicle conditions), engine reliability and cooling performance have been improved.
• The PCM determines the engine operation conditions (based on the signals from each sensor), and turns cooling fan relays No.1 and No.2 on/off to control the rotation speed of the cooling fan motor.
Block Diagram
Operation
• The PCM controls the cooling fan motor rotation speed by turning cooling fan relays No.1 and No.2 on/off based on each demand airflow volume.
Operation Pattern
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Demand airflow volume
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Cooling fan relay
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Cooling fan motor
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No.1
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No.2
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No airflow
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OFF
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OFF
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Stop
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Small
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ON
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OFF
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Low-speed
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Large
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ON
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ON
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High-speed
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Engine coolant temperature condition
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• Changes the demand airflow volume according to the engine coolant temperature.
• To suppress overheating, the cooling fan is operated when the engine coolant temperature is high. The demand airflow volume is large or small depending on the engine coolant temperature.
A/C operation condition (with air conditioner)
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• Controls the demand airflow volume depending on the refrigerant pressure and vehicle speed when the A/C switch is on.
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Operation condition
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Demand airflow volume
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• When any of the following conditions is met.
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― Refrigerant pressure: 1.3 MPa {13 kgf/cm2, 189 psi} or less, vehicle speed: 45 km/h {28 mph} or more
― Refrigerant pressure: 2.2 MPa {22 kgf/cm2, 319 psi} or less, vehicle speed: 85 km/h {53 mph} or more
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No airflow
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• When any of the following conditions is met.
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― Refrigerant pressure: 1.3 MPa {13 kgf/cm2, 189 psi} or less, vehicle speed: 45 km/h {28 mph} or less
― Refrigerant pressure: 1.3—1.5 MPa {14—15 kgf/cm2, 189—217 psi}, vehicle speed: 85 km/h {53 mph} or less
― Refrigerant pressure: 1.5—2.2 MPa {16—22 kgf/cm2, 218—319 psi}, vehicle speed: 65—85 km/h {41—52 mph}
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Small
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• When any of the following conditions is met.
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― Refrigerant pressure: 1.5—2.2 MPa {16—22 kgf/cm2, 218—319 psi}, vehicle speed: 65 km/h {40 mph} or less
― Refrigerant pressure: 2.2 MPa {22 kgf/cm2, 319 psi} or more
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Large
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After Cooling Control
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Without coolant control valve
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• After continuous, high-load driving, the cooling fan operates (demand airflow volume: small) for up to 9 min under the following conditions to suppress temperature increase inside the engine compartment.
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― Driving on ascending roads or after continuing to drive under high-load conditions
― After continuous, sudden acceleration from standstill and repeated, sudden acceleration
― Engine coolant temperature: 80 °C {176 °F} or more
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With coolant control valve
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• Operates the cooling fan in up to 2 steps according to the engine coolant temperature.
1st step
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― When the engine coolant temperature is 81 °C {178 °F} or more with the ignition switched OFF, the cooling fan is operated at MID for 4.5 min.
2nd step
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― When the engine coolant temperature is 110 °C {230 °F} or more after the 1st step is completed, the cooling fan is operated at MID until the temperature is less than 109 °C {228 °F}, or maximum of 2.5 min have elapsed.
Conditions during collision
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• If a collision signal from the SAS control module is received, the PCM stops the engine cooling fan to avoid use of battery voltage.
