Control system and method of continuously variable transmission

A control system of a continuously variable transmission having an automatic transmission mode, a manual transmission mode, said automatic transmission mode for controlling a speed ratio so as to equalize to a target speed ratio determined at least based on an engine speed, a vehicle speed and a throttle opening angle, said manual transmission mode when a speed range is selected manually among a plurality of predetermined speed ranges in order to make an up-shift or a down-shift for controlling said speed ratio so as to become equal to a specified speed ratio of said speed range, comprising:

• a change-over switch for outputting a signal when said automatic transmission mode is changed to said manual transmission mode;
• and
• speed ratio changing means responsive to said signal for changing said specified speed ratio of said manually selected speed range in the up-shift direction as said engine speed becomes high on the side of low speed ranges and in the down-shift direction as said vehicle speed becomes high on the side of high speed ranges.

A control method of a continuously variable transmission having an automatic transmission mode, a manual transmission mode, said automatic transmission mode for controlling a speed ratio so as to equalize to a target speed ratio determined at least based on an engine speed, a vehicle speed and a throttle opening angle, said manual transmission mode when a speed range is selected manually among a plurality of predetermined speed ranges in order to make an up-shift or a down-shift for controlling said speed ratio so as to become equal to a specified speed ratio of said speed range, comprising the steps of:

• outputting a signal when said automatic transmission mode is changed to said manual transmission mode;
• and
• responsive to said signal changing said specified speed ratio of said manually selected speed range in the up-shift direction as said engine speed becomes high on the side of low speed ranges and in the down-shift direction as said vehicle speed becomes high on the side of high speed ranges.

A control system of a continuously variable transmission having an automatic transmission mode, and a manual transmission mode, said automatic transmission mode for controlling an actual transmission ratio so as to become equal to a target transmission ratio determined at least based on engine speed, vehicle speed and throttle opening angle, said manual transmission mode when a speed range is selected manually among a plurality of predetermined speed ranges in order to make an up-shift or a down-shift for controlling said actual transmission ratio so as to become equal to a predetermined transmission ratio of said speed range, comprising:

• a change-over switch for outputting a signal when said automatic transmission mode is changed to said manual transmission mode;
• and
• transmission ratio changing means responsive to said signal for changing said predetermined transmission ratio of said manually selected speed range in the up-shift direction as said engine speed becomes high in lower speed ranges and in the down-shift direction as said vehicle speed becomes high in higher speed ranges.