Chevrolet Volt On-Road Test Programs in Canada. Part 2: Evaluation of Gasoline Displacement and Extreme Weather Performance in Comparison with Other Vehicles Types

Two test programs were conducted to investigate the on-road performance of model year 2012 Chevrolet Volts in Ottawa, Ontario, Canada. Specific testing routes were defined for various types of city and highway driving. Data loggers and additional instrumentation were installed in the vehicles to accurately monitor variables indicating the use of electricity for driving, as well as the use of fuel by the gasoline engine. The vehicles were tested during various seasons of the year to record their performance over the full range of climate conditions representative for a large part of Canada (from -27 °C to +37 °C). The test results were subsequently processed and analysed to compare the Volt’s performance in charge depletion mode (electric drive) to its operation in charge sustaining mode (hybrid drive). A ‘Gasoline Displacement Factor’ was introduced, which reflects the amount of grid electricity needed to replace one litre of gasoline used for driving the Volt. Test results show very low Gasoline Displacement Factors of 2 – 3.5 kWh/L for summer driving, while values of 3 – 9 kWh/L were observed for winter driving. The test results were also used to evaluate the additional amount of energy that the vehicles would need for driving, and cabin conditioning (heating in winter, air conditioning in summer) under conditions different from the more optimal 20-25 °C temperature range used for most standard performance tests. The Volt’s relative performance under extreme temperature conditions was compared to those of conventional gasoline vehicles, hybrid electric vehicles and battery electric vehicles. Additionally, recommendations for a more optimal use of the Volt under extreme temperature conditions are provided.