Dry Type Engine Clutch Control for a Parallel HEV at Launch Start Condition
A parallel type HEV has a power transfer device that is constructed by clutches and the device which is located between engine flywheel and electric traction motor is called 'Engine Clutch' When a traction motor of could not generate power to move, the HEV must launch only by engine power. In this situation the slip speed control and transmitted torque control are very important. In this study control strategies of dry type engine clutch is proposed to satisfy desired clutch engagement time and required torque at launch start condition. A dynamic model of a parallel type HEV driveline is constructed to apply the method proposed.
Model Reference Adaptive Control during Mode Transition of a Parallel Hybrid Electric Vehicle
Model reference adaptive control (MRAC) is proposed for torque coordination in order to improve dynamic performance during the mode transition of a parallel hybrid electric vehicle. Although model reference control (MRC) has been shown to be effective in controlling the mode transition, difficulties arise in application because the parameters of the reference model is unknown and time-varying. Small error of the parameter estimation may lead to instability of the MRAC system. With a reference model whose parameters are tuned by an estimator, the stability condition of the MRAC is derived. Thereafter, an adaptive law is designed to tune the feed-forward and feedback gains to satisfy the stability conditions for the mode transition. Simulation results show that the proposed MRAC can be stable even when the estimation error is large, and performs well under different road conditions.
Low-temperature thermal expansion of PEEK, HTA and some of their composites reinforced with carbon fibres
Abstract The thermal expansion of poly(ether ether ketone), a modification of poly (ether sulphone) and carbon fibre reinforced composites of these polymers has been measured over the range −153 to 27°C with a push-rod diameter. Where other measurements are available for comparison, agreement is obtained within experimental scatter. Some multidirectional composites are tested and the measured values of thermal expansion are explained qualitatively. It is thought that the specimen size has had a significant effect on these results. The longitudinal and transverse coefficients of thermal expansion of Hercules AS4 fibre have been calculated.