Energy efficiency optimization of a compound coupled hydro-mechanical transmission for heavy-duty vehicles

The concept of carbon neutrality makes scholars not only intensify their exploration on the utilization of new energy, but also further optimizing the utilization of traditional energy by improving energy management. Nearly half of energy losing among traditional internal combustion vehicle is due to energy delivering and operation. The CCHMT prototype enabled the vehicle to run smoothly and efficiently under harsh conditions. However, the large number of parameters makes the optimization of energy management system difficult, which adds a lot of troubles to the subsequent product serialization. Thus, after finishing research on CCHMT-3, a comprehensive optimization algorithm based on NSGA-II&SA is constructed to optimize the transmission characteristic parameters of CCHMT-4. By using the algorithm-optimized parameters, the AMEsim model simulation with CCHMT-4 shows better static speed regulation characteristics, efficiency characteristics and load stiffness characteristics. Furthermore, the dynamic characteristics of CCHMT-4 are simulated by DP dynamic programming algorithm, and the result shows that under the operation condition of JN1015, the fuel consumption rate is reduced by 13.9% compared with CCHMT-3. Subsequently, CCHMT-4 prototype processing and test-bed construction were carried out to verify the relevant characteristics of CCHMT-4. The experiment results show that the actual efficiency of CCHMT-4 is 80.6%–86.0%, the experimental data of fuel consumption is 0.701 kg, which shows better operation performance than CCHMT's former research. •NSGA-II&SA is constructed to optimize the transmission characteristic parameters of CCHMT.•It has been presented the simulation and experiment of a heavy-duty vehicle with CCHMT.•The fuel consumption rate is reduced by 13.9% through the parameters' optimization.•The actual efficiency has been reached 80.6%–86.0% with large speed regulation range.