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In order to study the dynamics coupling effect between human and vehicle on the roll characteristics of miniature electric vehicle (MEV), firstly mathematical models for roll motion and stable steering of human-vehicle system were established, respectively. And then, virtual prototype models of driver and MEVs were built by ADAMS/Car. Finally, simulations were conducted. The influences of human-vehicle dynamics coupling effect (HVDCE) on roll characteristics of MEV with different curb weight were compared and analysed. Results show that the vehicle dynamics models with HVDCE exhibit the characteristic of lower equivalent roll angular stiffness and equivalent roll angular damping under transient excitation, and the characteristic of greater roll angular damping at low frequency excitation. Besides, the HVDCE will decrease natural frequency of roll motion. The greater the proportion of the driver mass to the curb weight is, the more obvious the effect of HVDCE on the roll characteristics will be.

In order to obtain good starting performance of the electric scooter driven by brushless permanent-magnet direct circuit motor(BLPMDCM)，modules of RMxprt and Maxwell 2D in Ansoft software are used to build finite element simulation model of BLPMDCM. We simulated and studied the basic features and starting process of BLPMDCM. The results of internal magnetic field distribution and dynamic performance simulation are obtained when the motors are in different positions. The results provide a theoretical basis to further optimize the design, improve the starting torque and reduce torque ripple for this new type of permanent magnet motor and its control system.

According to the requirements of heavy commercial compressed natural gas (CNG) vehicle to satisfy China’s rapid economic development, the authors develop and test a new high energy direct ignition system of heavy CNG engine. Hardware and software of the high energy direct ignition system are designed and debugged. Based on the tradition test bench, an optimal test bench for this CNG engine is established. Ignition advance angle is calibrated and analyzed, which has the economy and power performances effects on CNG engine matched the developed high energy direct ignition system. To test the effects on engine emissions by high energy direct ignition system, ignition control strategy is simplified and optimized. In addition, high ignition energy is directly determined by current time of ignition coil power. A test study about torque, power and fuel consumption of this engine is accomplished. The final test results indicate that this developed high energy ignition direct system can satisfy the comprehensive performance objectives of heavy CNG engine.