Control method and apparatus for a continuously variable transmission

A control apparatus for a continuously variable transmission mechanism of an engine having a belt-type continuously variable transmission, the continuously variable transmission comprising:

• a starting clutch;
• a driving shaft;
• an input shaft operatively connected to a crankshaft of the engine through the starting clutch;
• an output shaft fixedly connected to the driving shaft and coaxial therewith,
• wherein the crankshaft rotates in a first direction of rotation during normal engine operation;
• wherein the starting clutch is connected to the crankshaft when a speed of the crankshaft exceeds a predetermined value, thus allowing power of the engine to be transmitted to the driving shaft through the continuously variable transmission,
• the control apparatus comprising:
• a gear ratio detector for detecting a gear ratio of the continuously variable transmission;
• an engine state detector for detecting whether the engine is in a stationary state;
• and
• an electric motor operatively connected to the crankshaft, said motor being capable of selectively and temporarily driving the crankshaft in a direction opposite to the first direction of rotation thereof such that the belt of the continuously variable transmission rotates backward when the engine is in a stationary state, and the gear ratio of the continuously variable transmission is greater than a predetermined reference value.

A method of controlling a continuously variable transmission mechanism of an engine having a belt-type continuously variable transmission, the continuously variable transmission comprising:

• a starting clutch;
• a driving shaft;
• an input shaft connected to a crankshaft of the engine through the starting clutch, wherein the crankshaft rotates in a first direction during normal engine operation;
• and
• an output shaft fixedly connected to the driving shaft and coaxial therewith, wherein the staffing clutch is connected to the crankshaft when a speed of the crankshaft exceeds a predetermined value, thus allowing power of the engine to be transmitted to the driving shaft through the continuously variable transmission,
• the control apparatus comprising:
• a first one-way clutch disposed between the output shaft of the continuously variable transmission and the driving shaft, the first one-way clutch rotating idly relative to a backward drive of the output shaft;
• a gear ratio detector for detecting a gear ratio of the continuously variable transmission;
• an engine state detector for detecting whether the engine is in a stationary state;
• and
• an electric motor operatively attached to the crankshaft, said motor being capable of selectively and temporarily driving the crankshaft in a direction opposite to the first direction of rotation thereof such that the belt of the continuously variable transmission rotates backward when the engine is in a stationary state and the gear ratio of the continuously variable transmission is greater than a predetermined reference value,
• the method of controlling the continuously variable transmission comprising the following method steps:
• step 1, determining the engine state via the engine state detector, and when the engine state is determined to be stationary, proceeding to step 2, otherwise repeating step 1,
• step 2, determining the gear ratio of the continuously variable transmission via the gear ratio detector, and when the gear ratio is less than or equal to a reference gear ratio returning to step 1, otherwise proceeding to step 3,
• step 3, activating the motor to drive the crankshaft in a reverse direction opposite to the first direction of rotation,
• step 4, determining the gear ratio of the continuously variable transmission via the gear ratio detector, and when the gear ratio is less than or equal to a reference gear ratio, terminating activation of the motor, otherwise returning to step 3.