To improve vehicle economy, this paper proposes a single planetary array hybrid system. Taking the heavy commercial tractor as the research object, the key parameters of automotive components are designed according to power performance indicators. The optimal control of the engine is taken as the basic principle, and the switching principles of the top-level working mode and sub-working mode of the vehicle are formulated. The mode switch strategy control program is written using Simulink, and the vehicle economic simulation model is established using Cruise. The results show that fuel consumption of the hybrid vehicle is lower than that of the traditional fuel vehicle in the fast transportation and coal transportation condition.

To enhance the fuel economy of the certain series-parallel hybrid commercial vehicle, a control strategy for optimizing engine speed based on the overall system efficiency has been proposed. This strategy comprehensively considers factors such as engine fuel consumption, planetary gear set mechanical losses, power losses during motor generation/driving/idling, controller power losses, and the conversion relationship between mechanical and electrical energy. Mathematical and control models for the series-parallel hybrid powertrain system have been established, with the objective of maximizing powertrain efficiency. Through iterative analysis of vast amounts of data, optimal solutions for engine speed and torque have been obtained. Simulation results indicate that, compared to a speed control strategy based solely on optimizing engine efficiency, the proposed strategy for optimizing overall system efficiency reduces vehicle fuel consumption by 7.9% under cyclic operating conditions. Finally, a series-parallel hybrid powertrain test bench is set up to verify the effectiveness of the control strategy, and the optimization effect on fuel economy is found to be significant.

This paper uses the high-altitude bench simulation test method to study the high-altitude characteristics of a non road four stage diesel engine with EGR technology route. It analyzes the changes in emissions, power and fuel economy of diesel engines with the increase of altitude in the EGR technology route, further explores the positive effect of EGR technology on performance improvement in high-altitude environments, and proposes a high-altitude performance optimization calibration method based on the technical characteristics of this model. Adopting this method helps to improve the engine’s high-altitude power performance.

To reduce the influence of the tractor low-resistance intake system on the cab interior noise, a modal simulation model of the intake system is established, and the main modal noise frequencies that affect the interior noise are located and defined. The paper studies the characteristics, noise reduction measures of intake system air passage assembly, air filter assembly and base assembly, along with thecorresponding noise reduction measures and effects. The modal characteristics of the above assemblies are precisely controlled and optimized, which effectively reducing the overall interior noise of the vehicle.

By installing the four-hole probe on the hood of a vehicle and some pressure taps on the surface of the vehicle to collect the wind flow parameters such as velocity, yaw angle, turbulent intensity, turbulent length scale, spectra etc.. In this study, transient wind characteristics on two test sites (Hainan Automobile Proving Ground and Yancheng Automobile Proving Ground) are investigated. The results showed that there are significant differences in the wind flow characteristics between the test site and wind tunnel experiments and numerical simulations. The wind velocity in the test site fluctuates within the range of ±4 m/s, the yaw angle fluctuates between -5° and 5°, and the yaw angle distribution follows the standard normal distribution, the turbulence intensity is almost in the range of 2%~10%, the turbulent length scale is 2~20 m, and the measured spectra show a good correlation to the empirical von Kármán spectra.

In order to analyze the difference between the high-temperature environment bench test and the real vehicle test results of high-temperature adaptability in the high-temperature verification of automobile interior and exterior trims, the high-temperature environment bench test and real vehicle environment test are carried out for passenger vehicle and SUV, and the differences are analyzed from the aspects of temperature, irradiance and wind speed. The results show that the main differences exist in irradiance, and it is proposed to install arc-shaped lamp support in the environment chamber and apply irradiance to the sides to reduce the differences, and thus enhance correctness of bench test.

In order to improve the efficiency and safety of thermal diffusion testing for power batteries, a three-dimensional model of the laboratory is established and gas diffusion simulation analysis is carried out based on actual data from a thermal diffusion laboratory. Regarding the issue of low diffusion efficiency of laboratory gases, the paper proposes an improved scheme to install dual suction ports directly above the cooling water tank. The simulation verification results show that the improved scheme reduces the peak CO₂ concentration by 25% and increases the CO₂ gas diffusion efficiency by 22.16% compared with the original scheme,, which effectively improves experimental efficiency and safety.