Malfunction detection device and method for a wheel speed sensor

• US 6,170,923 B1
• Filed: 08/24/1998
• Issued: 01/09/2001
• Est. Priority Date: 08/25/1997
• Status: Expired due to Term

• Current Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Inventors: Akata, Teruaki, Iguchi, Yutaka
• Primary Examiner(s): Schwartz, Christopher P.
• Assistant Examiner(s): SICONOLFI, ROBERT
• Application Number:
  US09/138,576
• Time in Patent Office: 869 Days
• Field of Search: 303/122.04, 303/122.05, 324/160, 324/161, 324/163, 324/164, 324/165, 324/166, 324/167, 324/168, 324/173, 324/174, 324/175, 324/177, 324/178, 324/179, 324/180, 73/488, 73/481, 73/491-498, 73/504.01-504.16, 73/507-512, 73/514.39, 73/519.01, 73/520.01
• US Class Current: 303/122.04
• CPC Class Codes: B60T 2270/415 Short-circuit, open circuit failure
• CPC Class Codes: B60T 2270/416 Wheel speed sensor failure
• CPC Class Codes: B60T 8/171 Detecting parameters used in the regulation; Measuring values used in the regulation
• CPC Class Codes: B60T 8/885 using electrical circuitry
• CPC Class Codes: G01P 21/02 of speedometers
• CPC Class Codes: G01P 3/4802 by using electronic circuits in general
• CPC Class Codes: G01P 3/489 Digital circuits therefor

Abstract

A malfunction detection device for a wheel speed sensor includes a comparison circuit for comparing a wheel speed signal output from a wheel speed sensor with a predetermined voltage. A calculation circuit is provided for selectively increasing or decreasing a counter according to an output signal of the comparison circuit. A malfunction signal output circuit outputs a malfunction signal when the counter of the calculation circuit reaches a predetermined value.

Claims

1. A malfunction detection device for a wheel speed sensor comprising:

a comparison circuit for comparing a wheel speed signal output from a wheel speed sensor with a predetermined voltage;

a calculation circuit selectively increasing or decreasing a counter according to an output signal of the comparison circuit;

a malfunction signal output circuit outputting a malfunction signal when the counter of the calculation circuit reaches a predetermined value; and

wherein speeds of the increase and the decrease of the counter differ from each other.

2. A malfunction detection device for a wheel speed sensor as recited in claim 1, wherein the speed of the decrease of the counter is larger than the speed of the increase of the counter.

3. A malfunction detection method for a wheel speed sensor comprising:

a comparison step for comparing a wheel speed signal output from a wheel speed sensor with a predetermined voltage and for outputting an output signal;

a calculation step for selectively increasing or decreasing a counter according to the output signal;

a malfunction signal output step for outputting a malfunction signal when the counter reaches a predetermined value;

wherein speeds of the increase and the decrease of the counter differ from each other.

4. A malfunction detection method for a wheel speed sensor as recited in claim 3, herein the speed of the decrease of the counter is larger than the speed of the increase of the counter.