Hybrid Electric Vehicle Full Vehicle Model

The hybrid electric vehicle (HEV) full vehicle model serves as a critical tool for researching and developing hybrid powertrain systems, enabling simulation of vehicle operational states and performance under various driving conditions. A comprehensive HEV model typically incorporates the following key subsystems:

Powertrain System Model The powertrain constitutes the core of the vehicle model, requiring simulation of coordinated operation between the engine, electric motor, and battery. The engine model must account for fuel consumption and emission characteristics, the motor model should reflect torque-speed characteristics, while the battery model needs to accurately depict energy changes during charge/discharge cycles. Implementation often involves lookup tables for efficiency mapping and state-space equations for battery dynamics.

Transmission System Model The transmission system responsible for delivering power to the wheels requires modeling of gear ratios, shift logic, and mechanical losses. Special attention must be given to accurate modeling of hybrid-specific power coupling devices like planetary gear sets. Code implementation typically uses state machines for gear shifting logic and efficiency matrices for loss calculations.

Vehicle Dynamics Model This component simulates forces acting on the vehicle during operation, including aerodynamic drag, rolling resistance, and grade resistance, along with inertial forces during acceleration/deceleration. Accurate dynamics modeling enables performance prediction across diverse road conditions. Implementation commonly employs Newtonian mechanics equations with resistance coefficients calibrated from experimental data.

Energy Management System This HEV-specific control strategy model optimizes operating points for both engine and motor, determining energy distribution patterns. Common control strategies include rule-based control, instantaneous optimization control, and global optimization control. Algorithm implementation may involve fuzzy logic controllers, equivalent consumption minimization strategies (ECMS), or dynamic programming approaches.

The complete vehicle model supports multiple research objectives: evaluating performance differences among various powertrain configurations, optimizing energy management strategies, predicting fuel economy and emission levels, and analyzing battery lifespan. Through simulation analysis, developers can identify potential issues before prototype manufacturing, significantly reducing development cycles and costs. Model integration typically uses co-simulation platforms like MATLAB/Simulink with component models exchanging data through standardized interfaces.