Giving a major fillip to its innovation-packed product line-up, Chennai-based auto major TVS Motor Co has been granted an Indian patent for automatic hybrid transmission (AHT) system for two-wheelers. The invention for which exclusivity has now been provided by Chennai patent office is related to a system involving a combination of a fixed speed transmission mechanism (FSTM) and a continuously variable transmission mechanism (CVTM).
Transmission systems are required to transmit power from one rotating member to another rotating member of a vehicle through various transmission mechanisms. There are two types of transmission mechanisms — a continuously variable transmission mechanism (CVTM) and a fixed speed transmi ssion mechanism (FSTM). Both of these transmission mechanisms have certain operating conditions under which the mechanisms work most efficiently to provide optimum output.
According to a patent document filed by TVS Motor, the CVTM employs belts to provide a range of continuously varying transmission ratios. However, frequent belt slips take place at low speeds and when there is a frequent change in the acceleration of the rotating members.
In contrast, the FSTM can provide one or more fixed transmission ratios. However, the number of transmission ratios that can be achieved in the FSTM is limited, hence, power transmission is not smooth. The FSTM, as compared to the CVTM, provides a better initial acceleration for rotating members and therefore a suitable transmission ratio at low speeds.
On the other hand, at high and constant speed conditions, the FSTM does not provide the desired transmission ratios for achieving maximum speed and smooth operation. Therefore, the CVTM in combination with FSTM can provide better efficiency at all operating speeds, the company said.
TVS Motor further said that due to design constraints, the transmission system of a two-wheeler provided only with the CVTM cannot be transformed into a hybrid transmission system that provide high transmission efficiency at all operating speeds irrespective of frequent acceleration. Hence, the design of the transmission system is required which will render the installation of the FSTM to be retrofittable and therefore provide high transmission efficiency at all operating speeds irrespective of frequent acceleration.
TVS Motor which claims to be the third largest two-wheeler manufacturer in India, had clocked a revenue of R11,244 crore in 2015-16. The company has annual production capacity of 3.2 million two-wheelers and 1.2 lakh three-wheelers.