Chevrolet Volt On-Road Test Programs in Canada Part 1: Effects of Drive Cycle, Ambient Temperature and Accessory Usage on Energy Consumption and Electric Range

Abstract

Environment Canada (EC) and Natural Resources Canada (NRCan) separately tested two 2012 Chevrolet Volts between 2013 and 2014 in Ottawa, Ontario on public roads in the summer and winter months using realistic cabin-climate control settings. More than 1300 trips were conducted over nine routes: three city, one congested, two arterial, one highway and two expressway routes. EC tests recorded cabin conditioning, traction battery and 12V accessory power, select vehicle component temperatures, regulated emission rates and exhaust flow, and DC charge energy. Both NRCan and EC tests measured cumulative electric distance, select CANbus signals and AC grid supply charge energy. Results from these studies were analysed to evaluate the overall performance of the Chevrolet Volt on public roads in climates representative of most of Canada (-27°C to 37°C) using realistic accessory settings. At warm temperatures (~25°C) the Chevrolet Volt’s on-road all-electric range generally exceeded the U.S. EPA sticker rating (57.9km), while at cold (<0°C) and hot temperatures (>25°C) the all-electric range decreased to as low as 27.5km and 47.3km, respectively. Cabin conditioning energy was found to be directly related to the difference between ambient and cabin temperature, except at low temperatures (<0°C) when the 1.4L engine activates to assist the thermal management system. On average, heating the cabin in the winter months consumed significantly more electric energy than cooling the cabin in the summer months. Summer city and highway driving resulted in the lowest energy consumption (Wh/km), while congested and expressway driving cycles resulted in the highest. In the winter months, many differences between the drive cycles were not discernible due to the high cabin conditioning energy consumptions.