Methodology to Evaluate CO2 Emissions of Light-Duty Vehicle for Real-World Driving from Multiple Laboratory Testing

Abstract

The influence of CO2 on Earth’s climate warming is significant. To quantitatively evaluate CO2 emissions in different test cycles, eight China 6 light-duty vehicles were tested under WLTC, CLTC-P and one RDE test, respectively. This study indicated that the CO2 emissions in all three test cycles were influenced by factors such as test weight, vehicle shape, and transmission. Additionally, the RDE test was also affected by road traffic conditions and driving style. There was a strong linear correlation (R2 = 0.99) between the CO2 emissions of CLTC-P and WLTC. The coefficients for Low Speed and High Speed were greater than 1, while the coefficient for Medium Speed was less than 1. Vehicle speed was the primary factor influencing CO2 emissions at Low Speed, whereas acceleration was the main factor at Medium Speed. Furthermore, there was also a strong linear correlation (R2 = 0.99) between the CO2 emissions of RDE and WLTC/CLTC-P, with coefficients close to or exceeding 1. Comparatively, utilizing data from both WLTC and CLTC-P provided more consistent errors compared to using only the measured CO2 emissions from either test. Overall, the estimated CO2 emissions using all three methods remained within an acceptable range under the four conditions.