Starter system fault detector

• US 3,870,954 A
• Filed: 10/09/1973
• Issued: 03/11/1975
• Est. Priority Date: 10/09/1973
• Status: Expired due to Term

• Current Assignee: Howard Eisen Fineman, Richard Eric Hanson
• Original Assignee: Howard Eisen Fineman, Richard Eric Hanson
• Inventors: Hanson, Richard Eric, Fineman, Howard Eisen
• Primary Examiner(s): Smith, Alfred E.
• Assistant Examiner(s): Karlsen, Ernest F.
• Application Number:
  US05/404,800
• Time in Patent Office: 518 Days
• Field of Search: 324/158MG,13P,133,15
• US Class Current: 324/380
• CPC Class Codes: F02N 11/10 Safety devices F02N11/08 takes precedence
• CPC Class Codes: G01R 19/16585 for individual pulses, ripple or noise and other applications where timing or duration is of importance G01R19/16519, G01R19/16538 and G01R19/16595 take precedence; for pulse duration and rise time, see G01R29/02 and subgroups
• CPC Class Codes: G01R 31/006 on road vehicles, e.g. automobiles or trucks testing of ignition installations peculiar to internal combustion engines F02P17/00

Abstract

A starter system fault detector includes means for detecting the initial peak current waveform of a starter motor and related components under test. A reference peak of the waveform is provided by either a fixed reference signal or a dynamic reference signal derived from and related to the maximum magnitude of the initial peak current waveform. In one embodiment the fault detector provides a fault indication if the magnitude of the initial current waveform signal fails to exceed the magnitude of the fixed reference signal during a predetermined time period. In another embodiment the fault detector provides a fault indication if the magnitude of the dynamic reference signal fails to exceed the magnitude of the initial current waveform recovery slope during a predetermined time period.

Claims

1. A starter system fault detector for use with an engine having a starter motor and an electrical starter system which supplies starter current to said starter motor during a starting sequence, said fault detector comprising, in combination:

means for detecting the initial starter current waveform peak to provide a first signal indicative thereof;

means for providing a reference signal indicative of a given starter current waveform peak;

means for comparing said first signal to said reference signal to provide an output signal indicative of the relative magnitude difference between said initial waveform peak and said given waveform peak;

means for providing a predetermined time period related to the time period of said initial waveform peak;

means responsive to said output signal for providing a fault signal if the polarity of said relative magnitude difference indicates that the initial starter waveform peak is greater than the reference signal, and the polarity of the relative magnitude difference fails to reverse and indicate a waveform value less than the reference signal during said predetermined time period; and

means responsive to said fault signal for providing a fault indication.

2. The fault detector according to claim 1, wherein said reference signal is a predetermined, fixed-value signal.

3. The fault detector according to claim 2, wherein said predetermined time period includes the time period when said initial waveform peak exhibits its maximum value.

4. The fault detector according to claim 3, wherein said means for providing a predetermined time period includes means responsive to a predetermined current level of said initial waveform peak for providing said time period after said starter current exceeds said current level.

5. The fault detector according to claim 1, wherein said reference signal is a given, fixed-value signal and wherein said means for comparing said first signal to said reference signal comprises a comparator having a first input to which said first signal is applied and a second input to which said reference signal is applied, so that said means responsive to said output signal provides said fault signal when the magnitude of said first signal fails to exceed said reference signal.

6. The fault detector according to claim 1, wherein said reference signal is a dynamic reference signal derived from and related to the maximum magnitude of said initial starter current waveform peak and wherein said predetermined time period includes only the portion of said time period of said initial waveform peak following the maximum magnitude of said initial current waveform peak.

7. The fault detector according to claim 6, wherein said means for providing said dynamic reference signal comprises a peak detector having an input coupled to said means for detecting the initial starter current waveform peak, said peak detector having an output;

and, said means for comparing said first signal to said dynamic reference signal comprises a comparator having a first input coupled to the output of said peak detector and a second input to which said first signal is fed, so that said means responsive to said output signal provides a fault signal when the magnitude of said dynamic reference signal fails to exceed the magnitude of said first signal.

8. The fault detector according to claim 7, wherein said means responsive to said output signal comprises a flip-flop having a set input coupled to said means for providing said predetermined time period, a reset input coupled to the output of said comparator, and said flip-flop having an output coupled to said means responsive to said fault signal.

9. The apparatus according to claim 8, including time delay means coupled between said input of said flip-flop and said means for providing a predetermined time period, said delay means being further coupled to said peak detector so that the output of said peak detector provides an output signal indicative of the maximum magnitude of said initial waveform peak during said delay period.