Control method of and system for automatic transmission for automotive vehicle
AssigneeNissan Motor Co., Ltd.
InventorsTadashi Suzuki, Yoshiro Morimoto, Hideo Hamada, Masaaki Suga, Masaaki Futagi
Life of this patent
Estimating the term…
Abstract
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.
Claims33
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 including a high gear ratio 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 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 when depressing the brake pedal after the accelerator pedal has been released thereby causing the automotive vehicle to begin said coasting operation;
- and
- downshift means responsive to said downshift command signal for shifting the automatic transmission from the high gear ratio down to the next lower adjacent gear ratio to increase the engine speed, resulting in an increase in a time period during which the engine speed will remain above the predetermined engine speed value to increase the time period of the 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 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 fuel cut-off signal generating means for generating a fuel cut-off signal whenever the engine speed is higher than a predetermined 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 method 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 depressing the brake pedal after the accelerator pedal has been released to cause said automotive vehicle to begin said coasting operation;
- and
- shifting the automatic transmission from the high gear ratio down to the next lower adjacent gear ratio 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 value remains above the predetermined engine speed to increase the time period of operation of the fuel cut-off means thereby improving fuel economy.
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.
A control system for an automotive vehicle having an engine, an accelerator pedal for the engine, a brake pedal, and an automatic transmission, the automatic transmission including a torque converter having a pump drivingly connected to the engine and an output member drivingly connected to at least one traction wheel of the automotive vehicle, the automatic transmission being shiftable between different gear ratios, said control system comprising:
- an accelerator pedal position detector operatively coupled to the accelerator pedal for generating an idle signal when the accelerator pedal is released;
- a brake pedal position detector operatively coupled to the brake pedal for generating a brake signal when the brake pedal is depressed;
- a fuel cut-off means responsive to said idle signal for suspending the supply of fuel to the engine whenever the engine operates in a predetermined state after the accelerator pedal has been released thereby causing the automotive vehicle to begin a coasting operation;
- and
- a downshift means, responsive to said brake signal and said idle signal, for downshifting the automatic transmission whenever the engine operates in said predetermined state when depressing the brake pedal after the accelerator pedal has been released to cause the automotive vehicle to begin said coasting operation.
A control system for an automotive vehicle having an engine, an accelerator pedal for the engine, a brake pedal and an automatic transmission, the automatic transmission including a torque converter having a pump drivingly connected to the engine and an output member drivingly connected to at least one traction wheel of the automotive vehicle, the automatic transmission being shiftable between different gear ratios including a predetermined gear ratio, said control system comprising:
- an accelerator pedal position detector operatively coupled to the accelerator pedal for generating an idle signal when the accelerator pedal is released;
- a brake pedal position detector operatively coupled to the brake pedal for generating a brake signal when the brake pedal is depressed;
- means operatively coupled to the automatic transmission for generating a gear ratio signal indicative of said predetermined gear ratio;
- means for generating a vehicle speed signal indicative of a vehicle speed of the automotive vehicle;
- a comparator means for comparing said vehicle speed signal with a predetermined reference vehicle speed value and for generating a range signal when said vehicle speed signal is greater than said reference vehicle speed value;
- means responsive to said idle signal for generating a fuel cut-off signal whenever the engine operates in a predetermined state after the accelerator pedal has been released thereby causing the automotive vehicle to begin a coasting operation;
- a fuel cut-off means responsive to said fuel cut-off signal for suspending the supply of fuel to the engine;
- means responsive to said gear ratio signal, said brake signal, said idle signal and said range signal for generating a downshift command signal whenever said gear ratio signal and said range signal are present when depressing the brake pedal after the accelerator pedal has been released to cause said automotive vehicle to begin said coasting operation;
- and
- a downshift means, responsive to said downshift command signal for downshifting the automatic transmission from the predetermined gear ratio to a lower gear ratio.
A control system for an automotive vehicle having an engine, an accelerator pedal for the engine, a brake pedal and an automatic transmission, the automatic transmission including a torque converter having a pump drivingly connected to the engine and an output member drivingly connected to at least one traction wheel of the automotive vehicle, the automatic transmission being shiftable between different gear ratios, said control system comprising:
- an accelerator pedal position detector operatively coupled to the accelerator pedal for generating an idle signal when the accelerator pedal is released;
- a brake pedal position detector operatively coupled to the brake pedal for generating a brake signal when the brake pedal is released;
- means, responsive to said idle signal for generating a fuel cut-off signal whenever the engine operates in a predetermined state after the accelerator pedal has been released thereby causing the automotive vehicle to begin a coasting operation;
- a fuel cut-off means responsive to said fuel cut-off signal for suspending the supply of fuel to the engine;
- means responsive to said brake signal and said fuel cut-off signal for generating a downshift command signal whenever said fuel cut-off signal is present after depressing the brake pedal;
- a downshift means responsive to said downshift command signal for downshifting the automatic transmission.
A control system for an automotive vehicle having a engine, an accelerator pedal and an automatic transmission, the automatic transmission including a torque converter having a pump drivingly connected to the engine and an output member drivingly connected to at least one traction wheel of the automotive vehicle, the automatic transmission being shiftable between different gear ratios, said control system comprising:
- an accelerator pedal position detector operatively coupled to the accelerator pedal for generating an idle signal when the accelerator pedal is released;
- a brake pedal position detector operatively coupled to the brake pedal for generating a brake signal when the brake pedal is depressed;
- means for generating an engine coolant temperature signal indicative of a coolant temperature of the engine;
- means responsive to said engine coolant temperature signal for generating a reference engine speed signal which varies according to said engine coolant temperature signal;
- means for generating an engine speed signal indicative of an engine speed of the engine;
- a comparator for comparing said engine speed signal with said reference engine speed and generating a fuel cut-off signal permission signal when said engine speed signal is greater than said reference engine speed signal;
- means responsive to said fuel cut-off permission signal and said idle signal for generating a fuel cut-off signal in response at least to said fuel cut-off permission signal;
- means for maintaining said fuel cut-off permission signal for a predetermined period of time after said engine speed signal has dropped below said reference engine speed signal;
- a fuel cut-off means responsive to said fuel cut-off signal for suspending the supply of fuel to the engine;
- means responsive to said brake signal and said fuel cut-off signal for generating a downshift command signal whenever said fuel cut-off signal is present after depressing the brake pedal;
- a downshift means responsive to said downshift command signal for downshifting the automatic transmission.
A control system for an automotive vehicle having an engine, an accelerator pedal for the engine, a brake pedal and an automatic transmission, the automatic transmission including a lock-up type torque converter having a pump drivingly connected to the engine and an output member drivingly connected to at least one traction wheel of the automotive vehicle, the automatic transmission being shiftable between different gear ratios, said control system comprising:
- an accelerator pedal position detector operatively coupled to the accelerator pedal for generating an idle signal when the accelerator pedal is released;
- a brake pedal position detector operatively coupled to the brake pedal for generating a brake signal when the brake pedal is depressed;
- means responsive to said idle signal for generating a fuel cut-off signal whenever the engine operates in a predetermined state after the accelerator pedal has been released thereby causing the automotive vehicle to begin a coasting operation;
- a fuel cut-off means responsive to said fuel cut-off signal for suspending the supply of fuel to the engine;
- means responsive to said brake signal for generating a downshift command signal when depressing the brake pedal after the accelerator pedal has been released;
- a downshift means responsive to said downshift command signal for downshifting the automatic transmission;
- means responsive to said downshift command signal for generating a lock-up command signal;
- and
- a lock-up means responsive to said lock-up command signal for causing the torque converter to lock up.
A control system for an automotive vehicle having an engine, an accelerator pedal for the engine, a brake pedal and an automatic transmission, the automatic transmission including a torque converter having a pump drivingly connected to the engine and an output member drivingly connected to at least one traction wheel of the automotive vehicle, the automatic transmission being shiftable between different gear ratios, said control system comprising:
- an accelerator pedal position detector operatively coupled to the accelerator pedal for generating an idle signal when the accelerator pedal is released;
- a brake pedal position detector operatively coupled to the brake pedal for generating a brake signal when the brake pedal is depressed;
- a fuel cut-off means responsive to said idle signal for suspending the supply of fuel to the engine whenever the engine operates in a predetermined state after the accelerator pedal has been released;
- means responsive to said idle signal and said brake signal for generating a downshift command when depressing the brake pedal after the accelerator pedal has been released whenever the engine operates in said predetermined state;
- means for generating a vehicle speed signal;
- means for generating a downshift prohibiting signal when said vehicle speed signal is greater than a downshift prohibiting vehicle speed value;
- means for preventing said downshift signal generating means from generating said downshift command signal as long as said downshift prohibiting signal is present;
- a downshift means responsive to said downshift command signal for downshifting the automatic transmission.
A control system for an automotive vehicle having an engine, an accelerator pedal for the engine, a brake pedal and an automatic transmission, the automatic transmission including a torque converter having a pump drivingly connected to the engine and an output member drivingly connected to at least one traction wheel of the automotive vehicle, the automatic transmission being shiftable between different gear ratios including a lowest gear ratio, said control system comprising:
- an accelerator pedal position detector operatively coupled to the accelerator pedal for generating an idle signal when the accelerator pedal is released;
- a brake pedal position detector operatively coupled to the brake pedal for generating a brake signal when the brake pedal is depressed;
- means responsive to said idle signal for generating a fuel cut-off permission signal as long as the engine operates in a predetermined state after the accelerator pedal has been released;
- means for generating a gear ratio signal when the automatic transmission selects the lowest gear ratio;
- means responsive to said gear ratio signal for generating a prohibiting signal;
- a fuel cut-off means responsive to said fuel cut-off permission signal and said prohibiting signal for suspending the supply of fuel to the engine whenever the engine operates in a predetermined state after the accelerator pedal has been released unless said prohibiting signal is present;
- and
- a downshift means responsive to said brake signal and said idle signal for downshifting the automatic transmission when depressing the brake pedal after the accelerator pedal has been released.
A control system for an automotive vehicle having an engine, an accelerator pedal for the engine, a brake pedal and an automatic transmission, the automatic transmission including a torque converter having a pump drivingly connected to the engine and an output member drivingly connected to at least one traction wheel of the automotive vehicle, the automatic transmission being shiftable between different gear ratios, said control system comprising:
- generating, responsive to the accelerator pedal, an idle signal when the accelerator pedal is released;
- generating, responsive to the brake pedal, a brake signal when the brake pedal is depressed;
- suspending, responsive to said idle signal, the supply of fuel to the engine whenever the engine operates in a predetermined state after the accelerator pedal has been released thereby causing the automotive vehicle to begin a coasting operation;
- and
- forcing, responsive to said idle signal and said brake signal, the automatic transmission to downshift as long as the engine operates in said predetermined state when depressing the brake pedal after the accelerator pedal has been released to cause the automotive vehicle to begin said coasting operation.
A control system for an automatic transmission for an automotive vehicle having an engine, an accelerator pedal, and a brake pedal, the automatic transmission including a torque converter having a pump drivingly connected to the engine and including an output member drivingly connected to at least one traction wheel of the automotive vehicle, the automatic transmission being shiftable between different gear ratios, said control system comprising:
- an accelerator pedal position detector operatively coupled to the accelerator pedal for generating an idle signal when the accelerator pedal is released;
- a brake pedal position detector operatively coupled to the brake pedal for generating a brake signal when the brake pedal is depressed;
- a microprocessor operatively coupled to said accelerator pedal position detector and said brake pedal position detector for generating a fuel cut-off signal whenever the engine operates in a predetermined state after the accelerator pedal has been released, thereby causing the automotive vehicle to begin a coasting operation and also for generating a downshift command signal as long as the engine operates in said predetermined state when depressing the brake pedal after the accelerator pedal has been released to cause the automotive vehicle to begin said coasting operation;
- a fuel cut-off means operatively coupled to said microprocessor for suspending the supply of fuel to the engine in response to said fuel cut-off signal;
- and
- a downshift means, operatively coupled to said microprocessor, for forcing the automatic transmission to downshift in response to said downshift command signal.
Dependencies are inferred from the claim text.