Investigation of Transmission Warming Technologies at Various Ambient Conditions

Abstract

This work details two approaches for evaluating transmission warming technology: experimental dynamometer testing and development of a simplified transmission efficiency model to quantify effects under varied real world ambient and driving conditions. Two vehicles were used for this investigation: a 2013 Ford Taurus and a highly instrumented 2011 Ford Fusion (Taurus and Fusion). The Taurus included a production transmission warming system and was tested over hot and cold ambient temperatures with the transmission warming system enabled and disabled. A robot driver was used to minimize driver variability and increase repeatability. Additionally the instrumented Fusion was tested cold and with the transmission pre-heated prior to completing the test cycles. These data were used to develop a simplified thermally responsive transmission model to estimate effects of transmission warming in real world conditions.For the Taurus, the fuel consumption variability within one standard deviation was shown to be under 0.5% for eight repeat Urban Dynamometer Driving Cycles (UDDS). These results were valid with the transmission warming system active or passive. Using the transmission warming system under 22°C ambient temperature, fuel consumption reduction was shown to be 1.4%. For the Fusion, pre-warming the transmission reduced fuel consumption 2.5% for an urban drive cycle at -7°C ambient temperature, with 1.5% of the 2.5% gain associated with the transmission, while consumption for the US06 test was shown to be reduced by 7% with 5.5% of the 7% gain associated with the transmission. It was found that engine warming due to conduction between the pre-heated transmission and the engine resulted in the remainder of the benefit. For +22°C ambient tests, the pre-heated transmission was shown to reduce fuel consumption approximately 1% on an urban cycle, while no benefit was seen for the US06 cycle. The simplified modeling results showed gains in efficiency ranging from 0-1.5% depending on the ambient temperature and drive cycle.

Experimental study on recoverable thermal energy from low thermal inertia exhaust heat recovery unit

“…Nevertheless, once certain mechanical targets and milestone are met in the future, the recalibration activities can be outsourced to the calibration engineers at Proton. Considering that the expedited warm-up generally yielded fuel economy improvement ranging from 1.6% to 10.6% 6,9,15,16,19 , it was assumed that objective improvements in coolant, engine oil, and CVT oil warm-up would generally improve the fuel consumption during NEDC test.…”

“…The combination of the fluids and metals present large thermal inertia and requires as much as 60%–65% of thermal energy to overcome the thermal inertia in the early phase of cold start. 13,14 The sooner the fluids and metals get into the optimum temperatures and stay within the recommended ranges, the lesser the intake port wall wetting, combustion heat quenching, 4,11,12 and parasitic losses 6-10,15,16 will negatively impact the fuel consumption throughout the vehicle operations.…”