Improved Automatic Transmission Warmup - Stand Alone Oil to Air (OTA) Transmission Cooling Strategy with Thermostatic Cold Flow Bypass Valve

The stand alone oil to air (OTA) transmission cooling strategy provides improved transmission cooling under high ambient air temperature operating conditions, which improves transmission reliability, durability and overall customer satisfaction. Another means of improving reliability and durability is through improved transmission warmup under low ambient air temperature operating conditions.

To allow for improved transmission warmup, a thermostatic cold flow bypass valve has been incorporated into the transmission oil cooler. The bypass valve shuts off flow to the transmission oil cooler until a predetermined fluid temperature has been achieved. Once this temperature is reached, oil is allowed to flow to the transmission oil cooler.

Visteon Climate Control Systems (VCCS) has tested both the stand alone OTA transmission cooling strategy with thermostatic cold flow bypass valve and the conventional transmission cooling strategy, comparing the transmission system warmup rates. The bypass valve allows the stand alone OTA transmission cooling system to warmup significantly faster than the conventional transmission cooling system. The conventional system does not receive any warmup benefits from the coolant.