No abstract

No abstract

A smooth mode transition is critical for the driveability of hybrid electric vehicles and is difficult to achieve owing to transient intervention of torques from the engine, the electric machine and the transmission. This paper presents a systematic control strategy during transition from the motor-only mode to the compound driving mode of a multi-mode hybrid electric vehicle using one electric machine. The proposed strategy divides the mode transition process into four consecutive operating phases and employs a fuzzy gain-scheduling proportional-integral-derivative controller as feedback to adapt various non-linearities. Dynamic modelling of the vehicle system emphasizing the dynamics of the engine, the transmission, the clutches and the drive axle is conducted for validation simulation. Simulation results show that the mode transition controlled by the designed fuzzy gain-scheduling proportional-integral-derivative controller is completed in 700 ms with the vehicle jerk below 3.5 m/s 3 and where the produced clutch frictional losses are only 56 J. The performance is better than those controlled by a conventional proportional-integral-derivative controller. A sensitivity study shows the proposed controller has good adaptability to disturbances caused by the changing road conditions, the uncertainties in engine system and the noise from clutch actuation.

More and more planetary gear mechanisms are being used in Hybrid Electric Vehicle (HEV) as multi-energy coupling mechanisms because of their compact structure, high transmission efficiency and strong load bearing capacity. In order to get all the planetary gear schemes that satisfy the requirements of topological characteristics and select the optimal scheme for Hybrid Electric Vehicle Planetary Gear Coupling Mechanism (HEV-PGCM) as the references for the following analysis and structure design. Firstly, a variety of HEV-PGCM schemes with required topological characteristics are designed by applying the Creative Design Method. Secondly, according to the design requirements of planetary gear transmission and HEV power coupling mechanism, combined with Matrix Theory, the scheme evaluating indicators and method for HEV-PGCM are presented and used for scheme analysis and optimal selection. The results indicate that this method is general for common use and it can provide reference schemes for the following structure parameter design and analysis of HEV-PGCM.

This paper presents the design and validation of a novel multi-mode transmission (MMT) for a hybrid electric vehicle (HEV) using a single electric machine (EM), which implies compact and low cost. The topology of the MMT planetary gearset is the same as that of conventional four speed automatic transmissions. The MMT uses two planetary gearsets and four clutches to combine an engine and an EM with the vehicle, and the EM is operated as a motor or a generator. The MMT realizes five power flow modes, which are developed into sixteen operating modes, including one motor-only mode, four engineonly modes, four compound driving modes, six braking modes, and one charging while parking mode. The single EM HEV solution avoids losses from another EM and extra power electronics which are employed in many existing HEVs. The properly arranged clutches transmit power flow more flexibly, allow direct mechanical power transmission from the engine to the drive shaft, and avoid spin loss for the engine and energy conversion loss for the electric components. The fuel consumption of the proposed hybrid vehicle system is compared with a benchmark vehicle which uses a planetary gearset, two EMs and no clutch. Simulation results under New European Driving Cycle show that the fuel consumption of the proposed HEV is comparable to the benchmark vehicle. Reasons for comparable results are explored, which indicates the fuel economy potential of the new concept.