An Advanced Transmission Design with a Continuously Variable Capability for V8 Engine Application in Passenger Cars and Light Trucks

摘要

This paper suggests that hydraulic variator technology offer a viable alternative for CVT capability in automotive applications with large displacement engines. Furthermore, the split-torque path arrangement provides a solution for packaging in production vehicles without significant modification. The efficiency and noise measurements made for the transmission support the conclusions. The possibility for significant reductions in component part count and weight would be realized if a more holistic approach to the vehicle system design were taken. For example, this particular transmission was designed for the maximum engine power point, which is developed at 5,700 rpm. Based on the concerns identified with this input speed, an engine with a maximum power delivery at a lower speed (3,800 rpm, for example) would eliminate two- (2) ranges in the mechanical system and would allow for an increase in HSU capacity with very little effect on the HSU diameter. This would result in a shorter transmission design with no diameter changes in the housing design. These kinds of design decisions need to be carefully considered when designing a transmission of this kind for a new vehicle application. Topics for future research include the optimization of the HSU elements for structural and hydraulic performance, Testing of the synchronous shift effectiveness should provide a clear definition of an acceptable tolerance range for shifting. Speed differences between the mechanical elements at a range shift point may be low enough to replace certain clutching elements with less sophisticated coupling devices without a compromise on shift feel. Long term operation of the prototype transmission should also be used to confirm the high levels of expected durability and reliability that could be possible from the avoidance of metal-to-metal contact within the HSU.