A New Equation for Fuel Economy of Hybrid Vehicles in Republic of Korea Based on 5-Cycle Test

Fuel economy labeling serves a market-driven system that provides consumers with essential information to encourage the purchase and development of highly efficient vehicles. Since 2012, Korea has utilized derived 5-cycle equations, modeled after the US 5-cycle fuel economy calculation method, to enhance the reliability of these labels. However, with the growing prevalence of environment-friendly vehicles, particularly hybrids, it has become necessary to reassess and validate these equations specifically for hybrid models. In this study, 20 of the latest hybrid vehicle models available in the Korean market were selected for comprehensive 5-cycle testing. By analyzing the correlation between 5-cycle and 2-cycle fuel consumption results, we evaluated the applicability of the current derived 5-cycle equations for Hybrid Vehicles (HVs) and subsequently developed dedicated equations tailored to their performance characteristics. The application of the derived 5-cycle equations for HVs to the fuel economy reveals a decrease in city fuel economy by up to 0.9 km/L and an increase in highway fuel economy by up to 2.2 km/L. Consequently, this adjustment is expected to lead to the reclassification of up to three models within each fuel economy rating category, ensuring more accurate and representative labeling for consumers..