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Electrical and Series Hybrid Vehicles are generally provided with single speed reduction gearbox. To improve performance and drive range, a two-speed gearbox with coordinated control of traction motor and gearshift actuator is proposed. For a two-speed gearbox, gearshift without clutch would increase the shifting effort. Active Synchronization is introduced for a smoother gearshift even without clutch. The quality of gearshift is considered as a function of applied shift force and time taken. To enhance the quality of the gearshift further, the location of the synchronizer in the transmission system is optimized. To validate the improvement in the quality of the gearshift, a mathematical model of the two-speed gearbox incorporating proposed location of synchronizer assembly along with active synchronization is developed. The qualitative and quantitative analysis of the results achieved is presented.

The necessity of hybrid vehicles and electric vehicles is well known by now for reasons like fossil fuel depletion, climate change, emission norms mandated by regulations etc. With the addition of electric motor, battery and associated power electronics, the cost of powertrain and hence the vehicle goes up, which is often a hindrance for OEMs and end-customers. With the objective to make a cost-effective strong hybrid, Tata Motors has approached this problem by taking economies of scale approach i.e. developing an add-on gearbox module, which can fit a family of cars, in a P3-off axis hybrid configuration to an electrically actuated AMT. This paper presents the preliminary simulations, which show this architecture yielding a reduction of fuel consumption by ~20% for a B-class sedan/compact SUV of ~1800kg and ~15% improvement in acceleration performance. Additionally, the design and packaging studies show the fitment possibility in a highly congested powertrain bay.

Single plate dry clutch is most commonly used in automotive transmission. This paper proposes a unique approach of modelling a single plate dry clutch in Simulink and Simscape simulation environment. Clutch model is divided into two subsystems as translational and rotational. The translational system is linear system of diaphragm and cushion spring as a two-degree freedom system. Nonlinearity of the diaphragm and cushion spring has been modelled based on experimental data. This enables to simulate friction torque variation during clutch engagement. In rotational system, frictional torque generation between flywheel-clutch disc and pressure plate-clutch disc has been modelled separately. This novel approach of developing separate friction models helps in understanding variation in torque carrying capacity due to rise in the temperature of the friction pads because of frictional and engine heat.