Ricardo has developed and demonstrated an advanced and cost-effective motorcycle Automated Manual Transmission (AMT) concept that offers the comfort and convenience of automatic and semi-automatic operation with better-than-manual fuel efficiency.
Manual transmissions predominate in almost all non-scooter two-wheeler categories; automated alternatives can be expensive and bring efficiency penalties. BY contrast, the Ricardo concept avoids these drawbacks and is comparatively simple to integrate into an existing product range.
Other than the ubiquitous CVTs of scooters, and the specialist hydrostatic and Dual Clutch Transmissions (DCTs) used on some premium or specialist products, motorcycles around the world are almost universally fitted with manual transmissions.
These offer a comparatively low cost solution, but one that is unable to deliver the convenience or comfort of automatic operation. In addition to issues of packaging, weight and cost, almost all automatic transmission technologies available for use on two-wheels come with a further significant drawback: efficiency. From hydrostatics, to DCTs, CVTs and conventional automotive-style planetary automatic transmissions, almost no automatic transmission can match the manual for fuel efficiency.
The Ricardo AMT demonstrator concept is based on the use of an unchanged manual gearbox from the base model (a BMW K1300S for the demonstrator), making it an ideal candidate for an add-on solution enabling manufacturers to offer a high quality automatic without significant manufacturing, supply chain or parts inventory costs. Clutch and gear actuation—in this case using the original clutch, slave cylinder and shift system—can be via electric motors and/or hydraulic actuation.
A Ricardo AMT transmission control unit (TCU) integrates with the original product’s ECU to provide complete control of pre-programmed ‘comfort’ and ‘sports’ modes, and allow a semi-automatic mode via push buttons on the handlebars for up and down shifts. In each case, automatic pull-away and ‘creep’ functions are controlled by the TCU and there is no clutch lever.
Shift interrupt is possible in all automatic and semi-automatic modes but as with the manual mode, for safety and to protect the engine/transmission internals, this is only available within the permitted engine speed range for the selected ratio.
We’ve demonstrated how an AMT solution can be provided as an adaptation of an existing manual transmission product comparatively easily and maximizing component commonality. As such, it provides a cost-effective option that can be offered by manufacturers, providing customers with a dynamic driving solution with the comfort of an automatic but with no loss of performance or efficiency. In addition, the shift calibration can be developed to suit the particular requirements of bikes in very different sectors, for example a fast shift for a sports bike or a more relaxed gear change for a cruiser bike.—Stefano Di Palma, AMT lead engineer for Ricardo Motorcycle
For motorcycle manufacturers, the Ricardo AMT offers the advantages in platform strategy and modularity, with the ability to offer an automatic and semi-automatic option at comparatively low cost in terms of development, parts count and inventory costs.
For drivers, it provides the comfort of an automatic product which is not only more efficient than existing automatic technologies available for two-wheelers, but in fully automatic mode it can also be more efficient than even a manual transmission, without loss of the typical motorcycle riding style and fun.