Electro-hydraulic control for reducing engagement shock in an automatic transmission

• US 4,898,049 A
• Filed: 07/02/1987
• Issued: 02/06/1990
• Est. Priority Date: 07/07/1986
• Status: Expired due to Fees

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Niikura, Yasuhiro
• Primary Examiner(s): Diehl, Dwight G.
• Assistant Examiner(s): Macris, Harold F.
• Application Number:
  US07/069,201
• Time in Patent Office: 950 Days
• Field of Search: 192/0.032, 192/0.033, 192/0.052, 192/0.076, 192/0.092, 192/0.096, 192/3.58, 192/103 R, 192/103 F, 74/866, 74/861, 364/424.1
• US Class Current: 477/114
• CPC Class Codes: F16D 2500/1045 Friction clutch
• CPC Class Codes: F16D 2500/3024 Pressure
• CPC Class Codes: F16D 2500/3067 Speed of the engine
• CPC Class Codes: F16D 2500/30818 Speed change rate of the input shaft
• CPC Class Codes: F16D 2500/3108 Vehicle speed
• CPC Class Codes: F16D 2500/31466 Gear lever
• CPC Class Codes: F16D 2500/5045 Control of engine at idle, i.e. controlling engine idle conditions, e.g. idling speed
• CPC Class Codes: F16D 2500/7061 Feed-back
• CPC Class Codes: F16D 48/066 Control of fluid pressure, e.g. using an accumulator F16D48/062, F16D48/068 take precedence
• CPC Class Codes: F16H 2059/425 Rate of change of input or turbine shaft speed
• CPC Class Codes: F16H 2061/0488 during range shift from neutral (N) to drive (D)
• CPC Class Codes: F16H 2200/2007 with two sets of orbital gears
• CPC Class Codes: F16H 2312/02 Driving off
• CPC Class Codes: F16H 3/66 composed of a number of gear trains without drive passing from one train to another
• CPC Class Codes: F16H 59/22 Idle position
• CPC Class Codes: F16H 61/0437 by using electrical signals F16H61/0403 and F16H61/061 take precedence
• CPC Class Codes: F16H 61/20 Preventing gear creeping ; Transmission control during standstill, e.g. hill hold control
• CPC Class Codes: F16H 61/686 with orbital gears

Abstract

In a control system for controlling engagement of a frictional element, such as a clutch, the derivative of the speed of an input member, such as a turbine shaft, of a transmission is calculated and compared to a target value. The difference, i.e., error, between the values is employed to control, hydraulically, the engagement of the frictional element. The control system operates the frictional element to reduce the error toward zero. This control routine operates only when the vehicle is idling.

Claims

1. In an automatic transmission having an output member and an input member that is drivingly connected to a torque converter which in turn is drivingly connected to an engine,

a frictional element that may be engaged in response to the flow of a hydraulic fluid to establish a torque delivery path in the automatic transmission, said frictional element being driven through the input member;

means, including a transmission valve which may be selectively placed in any of a plurality of running range positions and in a neutral range position, for supplying hydraulic fluid toward said frictional element when said transmission valve is shifted from the neutral range position to one of the running range positions;

means for sensing the speed of the input member of the automatic transmission and for generating a speed signal indicative of the speed;

means for sensing the idling state of the engine and for generating an idling signal indicative of the idling state of the engine;

a control unit including means receiving the speed signal and the idling signal for generating, only when the engine is in an idling state, a derivative signal indicative of the derivative with respect to time of the speed signal, means for generating a target derivative signal indicative of a target value of the derivative signal, and means for generating an error signal indicative of the difference between the derivative signal and the target derivative signal, and means responsive to the error signal for generating an output signal; and

means responsive to said output signal for controlling said hydraulic fluid supplying means to reduce said error signal toward zero.

2. An automatic transmission as claimed in claim 1 wherein said input member is a rotatable shaft and said means for sensing senses the rotational speed of said shaft.

3. In an automatic transmission having an output member and an input member that is drivingly connected to a torque converter which in turn is drivingly connected to an engine, a method of reducing shock during engagement of a frictional element that may be engaged to establish a torque delivery path in the automatic transmission in response to the flow of hydraulic fluid from a transmission valve which may be selectively placed in a number of running range positions and in a neutral range position when the transmission valve is shifted from the neutral range position to one of the running range positions, said method comprising:

sensing the speed of the input member of the automatic transmission and generating a speed signal indicative of the speed;

sensing the position of the transmission valve and generating a range signal indicative of the position sensed;

sensing the idling state of the engine and generating an idling signal indicative of the idling state of the engine;

calculating the derivative with respect to time of the speed signal and generating a derivative signal indicative of the derivative calculated only when the idling signal indicates the engine is idling;

generating, in response to the range signal, a target derivative signal indicative of a target value of the derivative signal;

calculating the difference between the derivative signal and the target derivative signal and generating an error signal indicative of the difference;

generating an output signal in response to said error signal; and

regulating the supply of hydraulic fluid from the transmission valve to the frictional element in response to the output signal to reduce the error singal toward zero.

4. In a vehicle having an engine, a torque converter having a pump impeller drivingly connected to the engine and a turbine runner:

an input member drivingly connected to the turbine runner;

an output member driven by the input member;

a planetary gear set having a sun gear drivingly connected to said input member, a ring gear, a planet carrier drivingly connected to said output member, said planet carrier rotatably supporting a planet pinion meshing with said ring and sun gears;

a frictional element operatively disposed between said ring gear and a stationary portion, said frictional element being hydraulically engaged to restrain rotation of said ring gear;

means, including a transmission valve which may be selectively placed in any of a plurality of running range positions and in a neutral range position, for supplying hydraulic fluid toward said frictional element when said transmission valve is shifted from the neutral range position to one of the running range positions;

means for sensing the speed of said input member and for generating a speed signal indicative of the speed;

means for sensing the idling state of the engine and for generating an idling signal indicative of the idling state of the engine;

a control unit including means receiving the speed signal and the idling signal for generating, only when the engine is in an idling state, a derivative signal indicative of the derivative with respect to time of the speed signal, means for generating a target derivative signal indicative of a target value of the derivative signal, and means for generating an error signal indicative of the difference between the derivative signal and the target derivative signal, and means responsive to the error signal for generating an output signal; and

means responsive to said output signal for controlling said hydraulic fluid supplying means to reduce said error signal toward zero.

5. In a vehicle having an engine, a torque converter having a pump impeller drivingly connected to the engine and turbine runner;

an input member drivingly connected to the turbine runner;

an output member driving by the input member;

a planetary gear set having a sun gear, a ring gear drivingly connected to said output member, a planet carrier, said planet carrier rotatably supporting a planet pinion meshing with said ring and sun gears;

a one-way clutch operatively disposed between said planet carrer and a stationary portion and restraining rotation of said planet carrier;

a frictional element operatively disposed between said input member and said sun gear, said frictional element being hydraulically engageable to drive said sun gear from said input member;

means, including a transmission valve which may be selectively placed in any of a plurality of running range positions and in a neutral range position, for supplying hydraulic fluid toward said frictional element when said transmission valve is shifted from the neutral range position to one of the running range positions;

means for sensing the speed of the input member of said automatic transmission and for generating a speed signal indicative of the speed;

means for sensing the idling state of the engine and for generating an idling signal indicative of the idling state of the engine;

a control unit including means receiving the speed signal and the idling signal for generating, only when the engine is in an idling state, a derivative signal indicative of the derivative with respect to time of the speed signal, means for generating a target derivative signal indicative of a target value of the derivative signal, and means for generating an error signal indicative of the difference between the derivative signal and the target derivative signal, and means responsive to the error signal for generating an output signal; and

means responsive to said output signal for controlling said hydraulic fluid supplying means to reduce said error signal toward zero.