Abstract
Although most electricity production contributes to air pollution, the vehicle environmental agency categorizes all EVs as zero-emission vehicles because they produce no direct exhaust or emissions. Currently available EVs have a shorter range per charge than most conventional vehicles have per tank of gas. EVs manufacturers typically target a range of 160km on a fully charged battery. The energy efficiency and driving range of EVs varies substantially based on driving conditions and driving habits. Extreme outside temperatures tend to reduce range, because more energy must be used to heat or cool the cabin. High driving speeds reduce range because of the energy required to overcome increased drag. Compared with gradual acceleration, rapid acceleration reduces range. Additional devices significant inclines also reduces range. Based on these driving modes and climate conditions, test method, this paper discusses the performance characteristics of EVs on energy efficiency and driving range. Test vehicles were divided by low/high-speed EVs. The differences of test vehicle are on the vehicle speed and size. Low-speed EVs is a denomination for battery EVs that are legally limited to roads with posted speed limits as high as 72 km/h depending on the particular laws, usually are built to have a top speed of 60 km/h, and have a maximum loaded weight of 1,400 kg. Each vehicle test was performed according to the driving modes and test temperature (35℃~-25℃). Also, the comparison of test methods was achieved by chassis dynamometer test about test vehicles. These methods are intended to both improve testing efficiency and provide a practical testing methodology that can be easily adapted to accommodate future testing enhancements.
As the temperature decreases, low-speed EVs was decreased 52.4% energy efficiency, 85.5% Mileage per charge, 7% maximum speed. In the case of high-speed EVs was decreased 39.7% energy efficiency, 41.4% mileage per charge. The characteristics of low-temperature operating conditions by EVs were the same. Looking at the result of the test mode type, UDDS mode shows the best results. And HWFET, US06, SC03, UDDS results appear in the order. The most impact on energy efficiency decrease was low-temperature conditions. And air-conditioning use, rapid acceleration deceleration, high speed operation, etc. showed that the influence. Also, the use of various additional devices affect the energy efficiency decreased.
KEYWORDS – Electric vehicles (EVs); State of Charge (SOC); Driving modes (UDDS, HWFET, US06, SC03, Cold UDDS); Test temperature conditions; SAE j 1634 method