This paper determines the impact of ambient temperature on energy consumption of a variety of vehicles in the laboratory. Several conventional vehicles, several hybrid electric vehicles, a plug-in hybrid electric vehicle and a battery electric vehicle were tested for fuel and energy consumption under test cell conditions of 20°F, 72°F and 95°F with 850 W/m₂ of emulated radiant solar energy on the UDDS, HWFET and US06 drive cycles.
At 20°F, the energy consumption increase compared to 72°F ranges from 2% to 100%. The largest increases in energy consumption occur during a cold start, when the powertrain losses are highest, but once the powertrains reach their operating temperatures, the energy consumption increases are decreased. At 95°F, the energy consumption increase ranges from 2% to 70%, and these increases are due to the extra energy required to run the air-conditioning system to maintain 72°F cabin temperatures. These increases in energy consumption depend on the air-conditioning system type, powertrain architecture, powertrain capabilities and drive patterns. The more efficient the powertrain, the larger the impact of climate control (heating or cooling) on the energy consumption.
A wealth of vehicle test data and analysis is used to explain the nuances of the behaviors of the different powertrain architectures at the different temperatures. Additionally, test procedure details, charge-sustaining challenges, cold-start penalties, cabin temperature pull-up and pull-down, idle fuel flow rates, engine operations, impact of degree of hybridization, and battery system resistances are discussed. The Appendix provides time history graphs of all the data.