Energy Efficiency Benefits of Active Transmission Warm-up under Real-World Operating Conditions

Active transmission warm-up systems are used by automotive manufacturers in effort to increase powertrain efficiency and decrease fuel consumption. These systems vary from one manufacturer to another, but their main goal is to capture waste heat from the powertrain and accelerate transmission fluid warm-up. In this study, the fuel consumption benefit from the active transmission warm-up system in a 2013 Ford Taurus 2.0 L EcoBoost is quantified on a cold start UDDS drive cycle at ambient temperatures of −7 and 21 °C. In addition to this, the fuel consumption and greenhouse gas emissions impact on the EPA 5-cycle test, hot start HWY drive cycle, and a cold start, constant speed drive cycle is also quantified. An extra effort to determine the maximum possible benefit of active transmission warm-up is made by modifying the test vehicle to provide external heating to pre-heat and further accelerate the transmission fluid warm-up. The cold start fuel consumption benefit with external pre-heating of the transmission fluid is quantified on a UDDS and constant speed drive cycle at an ambient temperature of −7 °C. Finally, the cold start fuel consumption impact of using cabin heat to warm up the interior of the vehicle is quantified on a UDDS drive cycle at −7 °C and its magnitude is compared to the fuel consumption benefits of the active transmission warm-up system.