US 5,515,272 AGranted

Apparatus for diagnosing automatic transmission based on engine speed as compared with reference range

AssigneeToyota Jidosha Kabushiki Kaisha

InventorsTakahiro Sakai, Atsuo Okumura, Koichi Miyamoto

Life of this patent

Estimating the term…

Loading patent…

Abstract

A diagnosing apparatus for diagnosing a vehicle automatic transmission system including an automatic transmission having frictional coupling devices, and solenoid-operated valves for controlling the frictional coupling devices to shift the automatic transmission according to shift commands generated by a control device, the apparatus including a speed detector for detecting an engine speed of the vehicle, a device for determining a reference range of the engine speed within which the engine speed is expected to fall when the transmission is placed in a position selected by a shift command, a device for determining whether a predetermined running condition of the vehicle is satisfied, and a defect detector for determining whether there exists a defect associated with the automatic transmission system, depending upon whether the detected engine speed is held within or outside the determined reference range when the predetermined vehicle running condition is satisfied.

Claims17

Dependent claims

A diagnosing apparatus for detecting a defect associated with an automatic transmission system of a motor vehicle, said automatic transmission system including (a) an automatic transmission having a plurality of operating positions, operatively connected to an engine of the vehicle through a fluid-actuated power transmitting device, and incorporating a plurality of frictional coupling devices for establishing said operating positions, (b) a plurality of solenoid-operated valves for controlling operating states of said frictional coupling devices according to shift commands, and (c) an electronic control device which generates the shift commands to place said automatic transmission in a selected one of said plurality of operating positions, depending upon a running condition of the vehicle, said diagnosing apparatus comprising:

engine speed detecting means for detecting a speed of said engine;
range determining means for determining a reference range of the speed of the engine within which the speed of the engine is expected to fall when said automatic transmission is placed in one of said operating positions which is selected by a shift command generated by said electronic control device;
condition determining means for determining whether said vehicle is placed in a predetermined running condition;
and
defect detecting means for determining whether there exists a defect associated with said automatic transmission system, depending upon whether the speed of the engine detected by said engine speed detecting means is held within or outside said reference range when said condition determining means determines that said vehicle is placed in said predetermined running condition.

2 more elements

engine speed detecting means for detecting a speed of said engine;
speed change detecting means for detecting a change in the speed of the engine in response to said shift command generated by said electronic control device;
and
non-defect determining means for determining that one of said solenoid-operated valves whose operating state should be changed to effect a shifting action of said automatic transmission according to said shift command is normally functioning, if said speed change detecting means has detected said change in the speed of the engine in response to said shift command.

1 more element

A diagnosing apparatus for detecting a defect associated with an automatic transmission system of a motor vehicle, said automatic transmission system including (a) an automatic transmission having a plurality of operating positions and incorporating a plurality of frictional coupling devices for establishing said operating positions, (b) a plurality of first solenoid-operated valves for controlling operating states of said frictional coupling devices according to shift commands, (c) a lock-up clutch disposed between said engine and said automatic transmission and having an engaged position for direct connection of said engine to said automatic transmission and a released position in which an output of the engine is transmitted to said automatic transmission through a fluid-actuated power transmitting device, (d) a second solenoid-operated valve for placing said lock-up clutch in a selected one of said engaged and released positions according to a lock-up command, and (e) an electronic control device which generates said lock-up command, and said shift commands to place said automatic transmission in a selected one of said plurality of operating positions, said diagnosing apparatus comprising:

engine speed detecting means for detecting a speed of said engine;
range determining means for determining a reference range of the speed of the engine within which the speed of the engine is expected to fall when said said lock-up clutch is placed in said engaged position according to a lock-up command generated by said electronic control device;
and
defect detecting means for determining whether said automatic transmission system is defective, depending upon whether the speed of the engine detected by said engine speed detecting means is held within or outside said reference range.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 08/359,617Filed 20 Dec 1994
Priority: JP 532547922 Dec 1993
Granted: 7 May 1996
Term ends: Not estimatedThe source records don’t support an estimate.

Classification18 codes

F16H 61/12
Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid…
F16H 59/24
Inputs being a function of torque or torque demand: dependent on the throttle opening
F16H 59/36
Control inputs to control units of change-speed- or reversing-gearings for conveying rotary motion: inputs being a function of speed
F16H 59/44
Inputs being a function of speed: dependent on machine speed , e.g. the vehicle speed