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COOLANT CIRCUIT ANALYSIS FOR RADIATOR FAN SELECTION FOR WATER COOLED MOTORCYCLE

ENGINE.

Narendra Bansode

R & D, Mahindra Two Wheelers Ltd.

Gamma Technologies User’s Conference, 23rd September 2013

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To study the Engine cooling system for radiator fan selection in different vehicle maneuver conditions. Problem Statement: The existing cooling fan on the radiator has 12V, 5A motor. It is required to reduce the total current rating of the electrical system. One way is to use lower current rated fan motor. The alternative fan available has 12V, 2.5A motor. New fan needs to provide sufficient cooling in all vehicle operating conditions. Both the fans are evaluated for different vehicle operating conditions.

OBJECTIVE

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METHODOLOGY

Engine cooling system Model

Coolant Pump map

Engine Heat Rejection

Radiator Fan Performance

map

CFD Radiator Fan

Selection 1D Analysis

Radiator, Fan geometry and

position

Vehicle Operating Condition

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Two radiator fans considered:

1. Fan A: Average speed : speed 1 Specifications: 12V, 5A 2. Fan B: Average speed : speed 2 Specifications: 12V, 2.5A Fan ON-OFF condition: ON-98° C Coolant Temperature OFF-94° C Coolant Temperature

INPUTS

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INPUTS

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INPUTS

Engine Heat Rejection (kW)

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INFLOW

OUTFLOW

USING COOL 3-D FOR MODELING COOLING SYSTEM

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RADIATOR ASSEMBLY FROM COOL-3D

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SIMULATION MODEL

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ENGINE IDLING CONDITION

Vehicle speed : 0 km/h. Engine speed:1500 rpm Ambient air temperature: 27° C

Fan Speed: Fan A

Fan Speed: Fan B

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Vehicle speed : 0 km/h. Engine speed:1500 rpm Ambient air temperature: 27° C

FAN ON

FAN ON

FAN OFF

FAN OFF

Engine out temperature for Fan: A

Engine out temperature for Fan: B

ENGINE IDLING CONDITION

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OBSERVATION

Fan A provides more cooling and runs for less duration while Fan B runs for more duration.

Engine out coolant temperature remains below maximum allowable

temperature.

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Vehicle speed : 100 km/h. Engine speed:8000 rpm Ambient air temperature: 27° C

HIGHWAY RUNNING CONDITION

Engine out temperature for Fan: A

Engine out temperature for Fan: B

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OBSERVATION

Both the fans do not start during entire cycle as Engine out coolant temperature remains below Fan start temperature.

As vehicle speed is low coolant temperature goes on increasing but stabilize

below Fan start temperature.

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Vehicle speed : 40 km/h. Engine speed:8000 rpm Ambient air temperature: 27° C

Engine out temperature for Fan: A

Engine out temperature for Fan: B

HILL CLIMBING CONDITION

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OBSERVATION

Both the fans do not start during entire cycle as Engine out coolant temperature remains below Fan start temperature.

As vehicle speed is low coolant temperature goes on increasing but stabilize at

below Fan start temperature.

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SIGNAL START STOP CONDITION

Vehicle speed : 40 km/h and 0 km/h. Ambient air temperature: 27° C

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SIGNAL START STOP CONDITION

Fan Speed: Fan A

Fan Speed: Fan B

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SIGNAL START STOP CONDITION

Engine out temperature for Fan: A

Engine out temperature for Fan: B

FAN ON

FAN OFF

FAN ON

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OBSERVATION

Fan A provides more cooling and engine out coolant temperature decreases below Fan OFF temperature. This is not observed in Fan B.

Engine out coolant temperature remains under maximum allowable limit in

both the cases.

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CONCLUSION

Fan B performs well with acceptable deviation in cooling system operation compared to Fan A in all considered vehicle operating conditions.

Engine out coolant temperature is maintained well below the coolant boiling

point temperature. From the observations in each of above cases, Fan B is safely selected for

cooling operation.

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