Continuously variable transmission with improved response time

A method for controlling a continuously variable transmission in a vehicle in response to sensed vehicle operating conditions, said vehicle having an engine, a continuously variable transmission having a first pulley engagable with said engine, a second pulley drivingly connected to said first pulley by a belt mounted between said first pulley and said second pulley, said first and second pulleys each having a fixed sheave and a movable sheave, a position of said movable sheaves of said first and second pulleys being controlled by a control system for obtaining different transmission ratios, said control system further controlling a speed of said engine, the method comprising:

• sensing vehicle operating conditions and determining a target transmission ratio and a target engine speed;
• disengaging said engine from said first pulley if said sensed vehicle operating conditions require a rapid transmission ratio change;
• increasing said speed of said engine to said target speed;
• rapidly reducing pressure to said first pulley and increasing pressure to said second pulley for adjusting said transmission ratio to said target transmission ratio;
• increasing said pressure to said first pulley;
• and
• reengaging said engine to said first pulley.

A vehicle comprising:

• an engine;
• a continuously variable transmission, said transmission having a first pulley engagable with said engine by a clutch device, a second pulley drivingly connected to said first pulley by a belt mounted between said first pulley and said second pulley, said first and second pulleys each having a fixed sheave and a movable sheave, a position of said fixed and movable sheaves defining a transmission ratio;
• and
• a control system having a throttle position sensor connected to said control system, said control system providing signals for controlling a position of said movable sheaves of said first and second pulleys, for controlling an engine speed of said engine and for controlling said clutch device;
• wherein said control system calculates a target transmission ratio and a target engine speed, and when said target transmission ratio requires a rapid change, said control system disengages said engine from said first pulley by disengaging said clutch device, said control system increases said engine speed to a target speed, said control system rapidly reduces hydraulic pressure to said first pulley and increases hydraulic pressure to said second pulley so as to rapidly change said transmission ratio to said target transmission ratio and subsequently increasing hydraulic pressure to said first pulley, said control system then reengages said engine to said first pulley by reengaging said clutch device.