Improvements in controls relating to engine braking in a continuously variable transmission

Claim 1

In a continuously variable transmission for a motor vehicle with an engine, comprising: a driver pulley shaft; a follower pulley shaft arranged in parallel to said driver pulley shaft; a driver pulley rotatable with said driver pulley shaft, said driver pulley including a first conical pulley part rotatable with said driver pulley shaft, and a second axially movable conical pulley part defining with said first conical pulley part a first pulley groove, said driver pulley including a driver pulley cylinder chamber, said second axially movable conical pulley part being displaceable in response to hydraulic fluid pressure within said driver pulley cylinder chamber toward said first conical pulley part; a follower pulley rotatable with said follower pulley shaft, said follower pulley including a third conical pulley part rotatable with said follower pulley shaft, and a fourth axially movable conical pulley part defining with said third conical pulley part a second pulley groove, said follower pulley including a follower pulley cylinder chamber, said fourth axially movable conical pulley part being displaceable in response at least to hydraulic fluid pressure within said follower pulley cylinder chamber toward said third conical pulley part; a V-belt extending through said first and second pulley grooves and tensioned between said driver and follower pulleys; said first and second conical pulley parts interposing therebetween said V-belt with a gripping force determined by the hydraulic fluid pressure within said driver pulley cylinder chamber; an actuator; means for regulating hydraulic fluid pressure in said driver pulley cylinder chamber in response to a position taken by said actuator, thereby to vary a ratio between said driver and follower pulleys; means for detecting various kinds of input information and generating output signals .indicative of said various kinds of input information; means receiving said output signals for adjusting the magnitude of said gripping force in response to said output signals of said detecting means, said adjusting means including means for activating said actuator in response to said output signals, means for detecting a demand for an engine brake running of the motor vehicle, and means for effecting a reduction in magnitude of said gripping force upon detecting said demand for the engine brake running of the motor vehicle.