Implementation of automatic manual transmission for a two wheeler

Abstract

The concept of Automatic Manual Transmission (AMT) is picking up speed in India after the launch of the Maruti Suzuki Celerio. But very few of the two-wheeler manufacturers in the world have tried to implement the AMT concept in a motorcycle. There are gearless motorcycles available which use a Continuously Variable Transmission (CVT) and a Centrifugal clutch, but this setup is very inefficient compared to a positive gear drivetrain. Thus these gearless motorcycles get low mileage and are also more expensive to manufacture. Geared motorcycles, on the other hand, have better starting torque, greater mileage and a higher span of gear ratios. They are also cheaper, but the average buyer is discouraged by the complexity of the operation. Even those familiar with riding a motorcycle do not shift optimally to obtain the best mileage/performance. The aim of this paper is to present an innovative AMT system developed and implemented on a manual geared motorcycle having a sequential constant-mesh gearbox with a multi-plate clutch. This was carried out by interfacing the manual gear shifting motorcycle with a microcontroller and using an electronic actuation mechanism to make it an automatic gear shifting motorcycle. The significant steps of this project would involve the sensor readouts of the parameters necessary, the actuation of the controls and, most importantly, the algorithm for the optimal shift points for a given motorcycle. These would be obtained experimentally and using the manufacturer data, if available. This AMT setup has been successfully developed and implemented. This setup can then be applied to any geared motorcycle with minimal structural changes without any modification to its existing gearbox. This converts the manual geared motorcycle into the automatic gear shifting motorcycle having better fuel economy and lower maintenance costs as compared to the conventional CVT motorcycles.