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.
Engine clutch pressure command control for a parallel hybrid vehicle at launching when traction motor failed
A parallel type HEV (Hybrid Electric Vehicle) has a power transfer device that is constructed by wet clutches and the device is called `Engine Clutch'. The Engine Clutch is located between engine and electric traction motor so it transfers power of engine when the engine is started and clutches are engaged or cut the power when regenerative braking is occurred. When a traction motor of a parallel type HEV (Hybrid Electric Vehicle) could not generate torque to launch, the HEV should launch only by engine power. Because the engine should rotate at the stated idle speed to prevent the engine stop the relative rotational speed of clutch input and output shaft starts from engine idle speed and ends to zero when clutches engaged. In this study a method for control pressure command of engine clutch is proposed to satisfy desired clutch engagement time and decrease shock. A dynamic model of a parallel type HEV powertrain (including hydraulic clutch control components) is constructed to validate the method proposed.
Centrifuge modelling of effects of shield tunnels on existing tunnels in soft clay
With the rapid development of the subway network,the phenomena of shield tunnels going across the adjacent tunnels are becoming more and more common.The interaction between shield tunneling and nearby tunnels is more complicated than the ordinary shield tunneling in intact soil strata.Based on the project of Shanghai Bund Passage crossing Metro Line 2,the method of centrifuge modeling together with the field measurement is employed to study the effects shield tunneling on nearby strata and existing tunnels.In centrifugal model tests,the effects simulation techniques considering the unloading of excavation,ground loss and grouting are developed to analyze the longitudinal settlement of the shield tunnel and the existing tunnel induced by the shield tunneling.Besides,the deformation distribution and settlement curves of the existing tunnels during shield construction are studied by using the monitoring data.