Investigation of Climate Control Power Consumption in DTE Estimation for Electric Vehicles 2014-01-0713

Distance to empty (DTE) estimation is an important factor to electric vehicle (EV) applications due to its limited driving range. The DTE calculation is based on available energy of the battery and power usage by the powertrain components (e.g. electric motor) and climate control components (e.g. PTC heater and electric AC compressor). The conventional way of estimating the DTE is to treat the power consumed by the climate control system the same as the power by the powertrain for either instantaneous or rolling average estimation. The analysis in this study shows that the power consumption by the climate control system should be estimated based on the current ambient conditions and driver's input instead of using the recorded data from the past driving cycles. The climate control should also be considered separately from the powertrain in power usage rolling average calculation, which results in improvements in DTE estimation especially for extreme hot and cold conditions. Additionally, the climate control power consumption shows unique characteristics during the initial period of cabin climate control. The effect of the AC pull-down and heating warm-up on DTE estimation is also analyzed here. An innovative method is proposed to average out the power usage output curve by the climate control system during the initial period of cabin conditioning. As a result, the DTE estimation for electric vehicles with cabin conditioning can have better accuracy and be more adaptable to the changes in climate control settings set by the driver.