Increasing Energy Efficiency of Vehicles Using Combined Electromechanical Engine-Transmission Systems

The emergence of electric and hybrid vehicles with separate axle or wheel drives offers the potential to control torque distribution between the front and rear wheels. The stepless, smooth control of electric motors enables the continuous operation of both axles, even on roads with high rolling resistance. This ensures an optimal torque distribution, enhancing the vehicle's overall efficiency. A synergistic effect in hybrid vehicles can be achieved by optimizing the control of both the internal combustion engine and electric motors, minimizing energy consumption during movement. Analysis indicates that hybrid vehicles' dynamic properties and handling can be improved by using the internal combustion engine for steady-state driving and electric energy for acceleration. Maintaining the internal combustion engine at a constant speed is a key factor in increasing energy efficiency, making the vehicle more responsive during acceleration. The proposed method facilitates the selection of the most effective power levels for both the internal combustion engine and the electric motor during the design phase. As the time required to accelerate the vehicle to maximum speed decreases, the ratio of the electric motor's power to the internal combustion engine's power increases. In practical application, it is important to ensure the proper functioning of the system that adjusts torque distribution between the axles. This system relies on sensors measuring normal loads on the front and rear axles, vehicle speed, and effective engine power. The number of sensors can be minimized by correlating the engine's effective power with the vehicle's rolling resistance. Experimental results confirmed the theoretical findings, showing that the free power of the engine dedicated to acceleration increased by 6.5% due to reduced energy losses in the wheel drive. These findings underline the potential for significant improvements in the energy efficiency of hybrid vehicles.