Search Results

This paper examines the powertrain and braking efficiency of a wide spectrum of light duty vehicles to illustrate the range of efficiencies that exist and to isolate the contribution of hybrid and non-hybrid powertrains in reducing fuel consumption. The paper also examines the change in vehicle energy demands, e.g. aerodynamics and rolling resistance from 2005 models to 2010 models to highlight the role that vehicle energy consumption reduction plays in determining total fuel consumption. EPA fuel economy certification data is analyzed using the metrics of vehicle limited fuel consumption and powertrain and braking efficiency. From the data, conclusions are drawn to create a list of the ten most efficient powertrains, based on the powertrain and braking efficiency metric, and the ten vehicles with the lowest vehicle limited fuel consumption. These metrics provide an informative basis for current and future technology evaluations.

The word hybrid has been synonymous with higher fuel economy. However, the standard measures of fuel economy in miles per gallon or fuel consumption in liters per 100 km are not able to describe whether any increase in fuel economy is due to the hybrid powertrain or due to other factors such as non-powertrain vehicle modifications. It would be beneficial to have a simple way to describe where the fuel economy benefit is coming from, either from vehicle related enhancements (non-powertrain) or powertrain related enhancements. In this paper, the simplified metrics of Vehicle Limited Fuel Consumption (VLFC) and Powertrain and Braking Efficiency (PABE) are developed. The metrics are then used to characterize hybrid and non-hybrid vehicles and deconvolve the contribution of hybrid and non-hybrid enhancements to vehicle fuel consumption. These metrics can be helpful for communicating to non-experts when examining cost/benefit ratios of potential actions to reduce fuel consumption.