ELECTRICAL FAN CONTROL [SKYACTIV-G 1.3, SKYACTIV-G 1.5]SM2759994
ELECTRICAL FAN CONTROL [SKYACTIV-G 1.3, SKYACTIV-G 1.5]

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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

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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 (without EGR cooler)

Demand airflow volume

Cooling fan relay

Cooling fan motor

No.1

No.2

No airflow
OFF
OFF
Stop
Small
ON
OFF
Low-speed
Large
ON
ON
High-speed

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Operation pattern (with EGR cooler)

Demand airflow volume

Cooling fan relay

Cooling fan motor

No.1

No.2

No airflow
OFF
OFF
Stop
Small
ON
OFF
Low-speed
Large
OFF
ON
High-speed

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Engine coolant temperature condition

• 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.
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A/C operation condition (with air conditioner)

• Controls the demand airflow volume depending on the refrigerant pressure and vehicle speed when the A/C switch is on.

Operation condition

Demand airflow volume

• When any of the following conditions is met.
― 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
No airflow
• When any of the following conditions is met.
― 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}
Small
• When any of the following conditions is met.
― 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
Large


After Cooling Control

SKYACTIV-G 1.3
• 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.
― 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
SKYACTIV-G 1.5
• Operates the cooling fan in up to 2 steps according to the engine coolant temperature.
1st step
― 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
― 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

• If a collision signal from the SAS control module is received, the PCM stops the engine cooling fan to avoid use of battery voltage.