Integrated experimental and simulation study on energy flow distribution and transient characteristics of hybrid electric vehicles across varied driving cycles

Energy flow analysis is pivotal for improving hybrid electric vehicle (HEV) efficiency. In this study, an integrated simulation model for a P3-architecture parallel HEV was developed and calibrated with experimental data, and energy flow distribution and transient behavior were evaluated across World Light Vehicle Test Cycle (WLTC), China Light-Duty Vehicle Test Cycle (CLTC-P) and New European Driving Cycle (NEDC). Headline results show fuel consumption of 5.37, 4.28 and 4.69 L per 100 km for WLTC, CLTC-P and NEDC, respectively. Despite the higher total energy demand of WLTC, aggregate drivetrain losses are the lowest among the three cycles, and engine operating points under WLTC and NEDC cluster in low to medium map regions that are consistent with better fuel economy. Motor efficiency ranks CLTC-P > NEDC > WLTC, reflecting the more rapidly varying load and speed under WLTC. The battery state of charge declines most rapidly in WLTC, with propulsion predominantly electric at low speeds and transitioning to parallel operation as speed increases. These findings provide validated, cycle-specific insights for calibrating control strategies and improving energy utilization in HEVs.