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In order to improve the performance of low temperature combustion of diesel engines to achieve ultra-low emissions and load condition expansions, exhaust gas recirculation (EGR) stratification in the cylinder was proposed to further intensify local EGR concentration and reduce the amount of EGR to acquire high average oxygen concentration within cylinder. In this study, the intake/exhaust port and combustion chamber models were explored by CFD software on a four-valve HD diesel engine, and fresh air and EGR respectively replaced by O2 and CO2 were introduced with division and timing intake strategies during the intake process for stratification optimization.

In recent years, strict emission regulations, the environmental awareness, and the high price of conventional fuels have led to the creation of incentive to promote alternative fuels. Among the alternative fuels, natural gas is very promising and highly attractive for its abundant resources, clean nature of combustion and low encouraging prices. But nitrogen oxides (NOx) emissions are still a problem in natural gas engines. In order to reduce NOx emissions, carbon dioxide (CO2), nitrogen (N2) and argon (Ar) were respectively introduced to dilute fuel-air mixtures in the cylinder. To this aim a 6.62 L, 6-cylinder, turbocharged, electronic controlled large-powered NG engine was subjected to a basic performance test to observe the effects of CO2, N2 and Ar on fuel economy and NOx emissions. During the test, the engine speed and torque were separately kept at 1450 r/min and 350 Nm.

In the internal combustion engine (ICE), about 40% of fuel energy is released into the atmosphere through waste gas. To recovery the energy, the Organic Rankine Cycle (ORC) has been widely used, and lots of previous studies have selected the rotating turbine as the expander of ORC. However, the rotating turbine has disadvantages of high manufacturing cost and narrow applicable range. For the above reasons, a free piston with constant force output which functions as expander in ORC is proposed to recover the waste energy of exhaust gas from internal combustion engine (ICE). In the system, the free piston with constant force output operates reciprocally to output work under the driving of working fluid R245ca, which absorbs heat from waste gas and provides vapor power.

The passive fault-tolerant approach for four-wheel independently driven and steered (4WID/4WIS) electric vehicles has been investigated in this study. An adaptive control based passive fault-tolerant controller is designed to improve vehicle safety, performance and maneuverability when an actuator fault happens. The proposed fault tolerant control method consists of the following three parts: 1) a fault detection and diagnosis (FDD) module that monitors vehicle driving condition, detects and diagnoses actuator failures with the inequality constraints; 2) a motion controller that computes the generalized forces/moments to track the desired vehicle motion using Model Predictive Control (MPC); 3) a reconfigurable control allocator that redistributes the generalized forces/moments to four wheels with equality constrained optimization.

In this paper, the predictive control strategy is employed to improve the current tracking performance of hub motor in 4WD electric vehicle due to its fast dynamic response. But the performance of the conventional predictive deadbeat current control suffers greatly from the parameter variations and other disturbances. Toward this, this paper presents a new predictive control strategy for hub motor; this control scheme combines an improved predictive control law with a state-observer to estimate the future motor currents and system disturbances based on a decoupled model. It provides a decoupled control of hub motor and offers stability against the variations in motor inductance and robustness against system uncertainties. The feasibility and validity of the proposed predictive current control strategy is verified through the simulation results.

To research the torsional vibration damping characteristic of magneto-rheological fluid dual mass flywheel (MRF-DMF) and the control system in power train, the multi-degree power train torsional vibration model which contains MRF-DMF and semi-active fuzzy control model are built, then the damping characteristic of MRF-DMF in several conditions are gained and compared with MRF-DMF when no control system. The result indicates: the damping characteristic of MRF-DMF effect on power train when using control is better than without control in idle, speed up, slow down, ignition and stalling, while the damping characteristic is less obvious in constant speed because the simulation condition and damping moment relatively stable.

In order to improve structure and performance of magneto-rheological dual mass flywheel (MRF-DMF), some parameters effects on dynamic characteristics are acquired by parameters analysis. The dynamic stiffness and loss angle in different current and different frequency are gained through dynamic characteristic test. The fluid-structure interaction finite element model of MRF-DMF is built and the accuracy is verified by comparison between test and simulation. Based on the model, the parameters analysis is done and the law of MRF viscosity, arc spring stiffness, working clearance, rotor radius and axial width effect on dynamic characteristics are gained, it will prove some guidance for the structure and performance improvement.