Abnormality determination device for a vehicle speed sensor

• US 4,759,212 A
• Filed: 12/01/1986
• Issued: 07/26/1988
• Est. Priority Date: 12/11/1985
• Status: Expired due to Term

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Sawada, Kazuhisa, Teratani, Tatsuo
• Primary Examiner(s): MYRACLE, JERRY
• Application Number:
  US06/936,313
• Time in Patent Office: 603 Days
• Field of Search: 73/118.1, 73/2, 73/117.3, 74/859, 74/872, 340/62, 364/551
• US Class Current: 73/115.02
• CPC Class Codes: F02D 2200/1015 Engines misfires
• CPC Class Codes: G01M 15/046 by monitoring revolutions for detecting misfire G01M15/11
• CPC Class Codes: G01P 21/02 of speedometers

Abstract

Provided is an abnormality determination device for a vehicle speed sensor which can prevent a memory unit from storing the erroneous result of abnormality determination of a vehicle speed sensor due to the engine racing when the vehicle is stationary. The device of the invention includes a revolution speed sensor for detecting a revolution speed of an output shaft of an automatic transmission and generating a speed signal, abnormality determination elements for inputting the speed signal of the revolution speed sensor and for determining if the revolution speed sensor is abnormal and for generating an abnormality signal in response to the determined result, a memory for storing the abnormality signal, and halt elements for preventing the memory from storing the abnormality signal when the automatic transmission is set at a neutral position or at a parking position.

Claims

1. An abnormality determination device for a vehicle speed sensor, said abnormality determination device comprising:

(a) a first revolution speed sensor for detecting a revolution speed of an output shaft of an automatic transmission and for generating a speed signal;

(b) abnormality determination means for inputting the speed signal of said first revolution speed sensor, for determining if said first revolution speed sensor is abnormal, and for generating an abnormality signal in response to the determined result;

(c) storage means for storing the abnormality signal; and

(d) halt means for preventing said storage means from storing the abnormality signal when the automatic transmission is set at a neutral position or at a parking position.

2. An abnormality determination device for a vehicle speed sensor as claimed in claim 1, wherein said first abnormality determination means determines the abnormality of said first revolution speed sensor when the vehicle is determined to be stationary by a vehicle speed sensor and said first revolution speed sensor generates a non-zero speed signal.

3. An abnormality determination device for a vehicle speed sensor as claimed in claim 2, wherein said first revolution speed sensor comprises a magnet attached to the output shaft of the automatic transmission and a reed switch attached on the body of the vehicle, said reed switch generating a pulse signal with access of a pole of said magnet rotated with the output shaft.

4. An abnormality determination device for a vehicle speed sensor as claimed in claim 2, wherein said first revolution speed sensor comprises a gear attached to the output shaft of the automatic transmission and an electromagnetic pickup unit attached on the body of the vehicle, said pickup unit generating a pulse signal with an access of a tooth of said gear rotated with the output shaft.

5. An abnormality determination device for a vehicle speed sensor as claimed in claim 2, wherein said storage means is an electronic memory device.

6. An abnormality determination device for a vehicle speed sensor, said abnormality determination device comprising:

(a) a first revolution speed sensor for detecting a revolution speed of an output shaft of an automatic transmission and for generation a speed signal;

(b) a second revolution speed sensor for generating a speed signal;

(c) abnormality determination means for inputting the speed signals of said first and second speed sensors, for determining the abnormality of either one of said first and second revolution speed sensors when the difference of the speed signals between said two sensors is greater than a preset value, and for generating an abnormality signal in response to the determined result;

(d) storage means for storing the abnormality signal; and

(e) halt means for preventing said storage means from storing the abnormality signal when the automatic transmission is set at a neutral position or at a parking position.

7. An abnormality determination device for a vehicle speed sensor as claimed in claim 6, wherein said first revolution speed sensor comprises a magnet attached to the output shaft of the automatic transmission and a reed switch attached on the body of the vehicle, said reed switch generating a pulse signal with access of a pole of said magnet rotated with the output shaft.

8. An abnormality determination device for a vehicle speed sensor as claimed in claim 6, wherein said first revolution speed sensor comprises a gear attached to the output shaft of the automatic transmission and an electromagnetic pickup unit attached on the body of the vehicle, said pickup unit generating a pulse signal with an access of a tooth of said gear rotated with the output shaft.

9. An abnormality determination device for a vehicle speed sensor as claimed in claim 6, wherein said storage means is a constituent of a self diagnosis device for an electronic controlled automatic transmission.

10. An abnormality determination device for a vehicle speed sensor as claimed in claim 6, wherein said storage means is an electronic memory device.

11. An abnormality determination device for a vehicle speed sensor, said abnormality determination device comprising:

(a) a first revolution speed sensor for detecting a revolution speed of an output shaft of an automatic transmission and for generating a speed signal;

(b) abnormality determination means for inputting the speed signal of said first revolution speed sensor, for determining if said first revolution speed sensor is abnormal, and for generating an abnormality signal in response to the determined result, said abnormality determination means determining the abnormality of said first revolution speed sensor when the vehicle is determined to be stationary by a vehicle speed sensor and said first revolution speed sensor generates a non-zero speed signal;

(c) storage means for storing the abnormality signal, said storage means being a constituent of a self diagnosis device for an electronic controlled automatic transmission; and

(e) halt means for preventing said storage means from storing the abnormality signal when the automatic transmission is set at a neutral position or at a parking position.