Abstract The apparatus for controlling the CVT for a vehicle includes means for controlling a desired speed ratio of the CVT, means for storing a map of engine speed versus positions of the throttle valve for providing the minimum fuel consumption and means for calculating, by use of the map, a desired engine speed value corresponding to the detected throttle position. Also provided are means for determining a first operating area of the engine speed based upon the throttle opening, which area is spaced from the desired engine speed and is capable of providing sufficient power to obtain a smooth acceleration at a fixed transmission ratio as well as means for determining a second operating area of the engine speed based on the vehicle speed where the engine speed is high in relation to the vehicle speed, the second area being spaced from the desired engine speed and being capable of providing sufficient power to obtain a smooth acceleration at a fixed transmission ratio. Means are also provided for providing a signal to the transmission varying means for maintaining a current fixed speed ratio when the engine is operating in the first or second area, as well as means for providing a signal to the transmission varying means for varying the speed ratio so that the actual engine speed corresponds to the desired engine speed when the engine is in an area other than the first and second areas.
A continuous variable transmission for a vehicle provided with an internal combustion engine, which engine has a throttle valve, said transmission comprising: transmission means arranged between the engine and the vehicle for obtaining a continuously changeable transmission ratio; means for controlling a desired speed ratio of the transmission means; means for storing a map of engine speed versus positions of said throttle valve for providing the minimum fuel consumption; means for detecting an actual position of the throttle valve; means for detecting an actual engine speed; means for detecting an actual vehicle speed; first calculating means for calculatng, by use of said map, a desired engine speed value corresponding to the detected throttle position; means for determining a first operating area of the engine speed Nr2 based upon throttle opening, which area is spaced from said desired engine speed and is capable of providing sufficeint power to attain a smooth acceleration at fixed transmission ratio, due to an absence of transmission loss; means for determining a second operating area of an engine speed Nr1 based upon a vehicle speed where the engine speed is high in relation to vehicle speed, which second area is spaced from said desired engine speed and is capable of providing sufficient power to obtain a smooth acceleration at a fixed transmission ratio together with the absence of transmission loss; means for providing a signal to the transmission varying means for maintaining a current fixed speed ratio when the engine is operating in said first or second area; and means for providing a signal to the transmission varying means for varying the speed ratio so that the actual engine speed corresponds to the desired engine speed when the engine is in an area other than said first and second areas.
Claim 2
Dependent Claim
294 words
A continuous variable transmission for a vehicle provided with an internal combustion engine, which engine has a throttle valve, said transmission comprising: transmission means arranged between the engine and the vehicle for obtaining a continuously changeable transmission ratio; means for controlling a desired speed ratio of the transmission means; means for storing a map of engine speed versus positions of said throttle valve for providing the minimum fuel consumption; means for detecting an actual position of the throttle valve; means for detecting an actual engine speed; means for detecting an actual vehicle speed; first calculating means for calculatng, by use of said map, a desired engine speed value corresponding to the detected throttle position; means for determining a first operating area of the engine speed Nr2 based upon throttle opening, which area is spaced from said desired engine speed and is capable of providing sufficeint power to attain a smooth acceleration at fixed transmission ratio, due to an absence of transmission loss; means for determining a second operating area of an engine speed Nr1 based upon a vehicle speed where the engine speed is high in relation to vehicle speed, which second area is spaced from said desired engine speed and is capable of providing sufficient power to obtain a smooth acceleration at a fixed transmission ratio together with the absence of transmission loss; means for providing a signal to the transmission varying means for maintaining a current fixed speed ratio when the engine is operating in said first or second area; and means for providing a signal to the transmission varying means for varying the speed ratio so that the actual engine speed corresponds to the desired engine speed when the engine is in an area other than said first and second areas.