초록 ▼

An automatic transmission is changed from the highest gear ratio to the next lower gear ratio upon depressing the brake pedal after the accelerator has been released to cause the automotive vehicle to begin a coasting operation as long as the engine speed is higher than a predetermined engine speed.

An automatic transmission is changed from the highest gear ratio to the next lower gear ratio upon depressing the brake pedal after the accelerator has been released to cause the automotive vehicle to begin a coasting operation as long as the engine speed is higher than a predetermined engine speed. As a result the engine speed increases, resulting in an increase in the time period when the engine speed remains above the predetermined engine speed to enhance the time period of the operation of fuel cut means, thereby improving fuel economy.

대표청구항 ▼

A control system for an automatic transmission for an automotive vehicle having an engine, an accelerator pedal and a brake pedal, the automatic transmission being adapted for shifting between different gear ratios according to a shift pattern, and including an output member drivingly connected to a

A control system for an automatic transmission for an automotive vehicle having an engine, an accelerator pedal and a brake pedal, the automatic transmission being adapted for shifting between different gear ratios according to a shift pattern, and including an output member drivingly connected to at least one traction wheel of the automotive vehicle and a torque converter including a pump drivingly connected to the engine, the engine having a fuel cut-off signal generating means for generating a fuel cut-off signal whenever the engine speed is higher than a predetermined engine speed value after the accelerator pedal has been released to cause the automotive vehicle to begin a coasting operation, and a fuel cut-off means responsive to the fuel cut-off signal for suspending the supply of fuel to the engine, said control system comprising: a brake pedal position detector operatively coupled to the brake pedal for generating a brake signal when the brake pedal is depressed; circuit means responsive to said brake signal for generating a downshift command signal whenever the engine operates at an engine speed higher than the predetermined engine speed value when depressing the brake pedal after the accelerator pedal has been released to cause the vehicle to begin said coasting operation; and downshift means responsive to said downshift command signal for forcing the automatic transmission to downshift to increase the engine speed, resulting in an increase in a time period during which the engine speed remains above the predetermined engine speed value to increase the time period of operation of the fuel cut-off means thereby improving fuel economy. A control method for an automatic transmission for an automotive vehicle having an engine, an accelerator pedal and a brake pedal, the automatic transmission being adapted for shifting between different gear ratios including a high gear ratio according to a shift pattern, and including an output member drivingly connected with at least one traction wheel of the automotive vehicle and a torque converter including a pump drivingly connected to the engine, the engine having fuel cut-off signal generating means for generating a fuel cut-off signal whenever the engine speed is higher than a predetermined engine speed value after the accelerator pedal has been released to cause the automotive vehicle to begin a coasting operation and a fuel cut-off means responsive to the fuel cut-off signal for suspending the supply of fuel to the engine, said control system comprising: generating a brake signal responsive to the brake pedal when the brake pedal is depressed; generating a downshift command signal responsive to said brake signal when the engine operates at an engine speed higher than said predetermined engine speed value when depressing the brake pedal after the accelerator pedal has been released to cause the vehicle to begin said coasting operation; and forcing the automatic transmission to downshift in response to said downshift command signal to increase the engine speed, resulting in an increase in a time period during which the engine speed remains above the predetermined engine speed value to increase the time period of operation of the fuel cut-off means thereby improving fuel economy.