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Powertrain efficiency in a recent study was defined as the ratio of tractive work (integrated power) needed for a vehicle to complete a drive cycle divided by the fuel energy consumed. In short, this is a measure of how good the powertrain is at getting fuel energy to the road. Many cars have a fuel economy advantage over light trucks due to weight and aerodynamics, but there is not a lot of difference in the powertrain efficiencies by vehicle class. There is a difference, however, in the powertrain efficiency between a hybrid vehicle and its conventional counterpart.

The study compared powertrain efficiency for eight pairs of same-model vehicles for MY2013; the values for powertrain efficiency for conventional vehicles were compared to their hybrid counterparts using data from the Environmental Protection Agency’s Office of Transportation and Air Quality. Of the vehicles in the study, the VW Jetta showed the greatest difference between the conventional and hybrid powertrains with the hybrid showing 72.6% improvement. All hybrids in the study had an average efficiency gain of 45.1% over their conventional counterparts. Models that show less improvement with a hybrid powertrain may reflect a more efficient conventional powertrain so caution should be used in comparing the models listed. It is also worth noting that even more modest efficiency improvements for larger vehicles, such as the Chevrolet Tahoe, can have a great impact on overall fuel consumption.

Powertrain Efficiency Improvement for Selected Hybrid vs. Conventional 2013 Counterparts

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Fact #883 Dataset

Supporting Information

Powertrain Efficiency Improvement for Selected Hybrid vs. Conventional 2013 Vehicles
Make and ModelImprovement in Powertrain Efficiency
VW Jetta72.6%
Toyota Highlander55.5%
Toyota Camry52.2%
Honda Civic37.3%
Hyundai Sonata33.1%
Ford Escalade32.7%
Nissan Pathfinder27.5%
Chevrolet Tahoe23.0%
All45.1%

Note: The hybrid Nissan Pathfinder was a 2014 model.
Source: Thomas, J., "Drive Cycle Powertrain Efficiencies and Trends Derived from EPA Vehicle Dynamometer Results," SAE Int. J. Passeng. Cars - Mech. Syst. 7(4):2014, doi:10.4271/2014-01-2562. SAE 2014 International Powertrain, Fuels & Lubricants Meeting, October 20-23, 2014, Birmingham, UK. Based on data from the Environmental Protection Agency, Light-Duty Automotive Technology, Carbon Dioxide Emissions, and Fuel Economy Trends database.

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