Single sensor engine analyzer with noise rejection and automatic triggering circuit

• US 4,170,131 A
• Filed: 11/25/1977
• Issued: 10/09/1979
• Est. Priority Date: 11/25/1977
• Status: Expired due to Term

• Current Assignee: Clayton Manufacturing Company
• Original Assignee: Clayton Manufacturing Company
• Inventors: Olsen, Dick M., Gniewek, Stephen A.
• Primary Examiner(s): Myracle, Jerry W.
• Application Number:
  US05/854,768
• Time in Patent Office: 683 Days
• Field of Search: 73/117.3, 73/116, 324/16 T, 324/16 S
• US Class Current: 73/114.62
• CPC Class Codes: F02P 17/02 Checking or adjusting ignition timing
• CPC Class Codes: F02P 17/06 using a stroboscopic lamp
• CPC Class Codes: F02P 17/08 using a cathode-ray oscilloscope F02P17/06 takes precedence
• CPC Class Codes: G01M 15/05 by combined monitoring of two or more different engine parameters

Abstract

An internal combustion engine analyzer is described which permits analysis to be performed by attaching one sensor to the engine circuit. Timing at idle, engine speed, plug firing parade, etc., can be performed with only one sensor connected to the engine. For more extensive testing wherein additional leads are used, for example, at both the primary and secondary of the engine ignition coil, circuitry is provided for automatically triggering from both primary and secondary input signals or either one if only one is present. The analyzer also contains circuitry that enhances its use with both standard and electronic ignition systems. This circuitry rejects the noise generated by ignition systems in the cylinder ignition signals representative of plug firing so as not to mistrigger, or fire more than once for each plug firing.

Claims

1. In an apparatus for analyzing the operations of a multiple cylinder internal combustion engine, improved means for detecting cylinder ignition signals, said improvement comprising:

means coupled to the engine for sensing signals representative of cylinder ignition;

one-shot multivibrator means responsive to the signals representative of cylinder ignition for generating a short pulse in response to the input signals;

a constant peak-amplitude ramp generator means responsive to the short pulses from said one-shot multivibrator for generating ramp signals varying in slope in relation to the frequency of the short pulses received; and

an amplitude comparator means receiving the ramp signals from said ramp generator means for providing a first level output whenever the amplitude of the ramp signal exceeds a predetermined amount or providing a second level output whenever the amplitude of the ramp signed is below the predetermined amount, said signal levels being supplied to said one-shot multivibrator means to enable and disable, respectively, the triggering of said one-shot multivibrator means.

2. In an apparatus for analyzing the operation of a multiple cylinder internal combustion engine, improved means for detecting cylinder ignition signals, said improvement comprising:

means coupled to the engine for sensing signals representative of cylinder ignition;

schmitt trigger means responsive to the signals representative of cylinder ignition for generating pulses in response thereto;

integrator means responsive to said schmitt trigger means for generating a voltage level;

first comparator means responsive to the voltage level output of said integrator means for generating a first level if the voltage level from the integrator exceeds a predetermined value or generating a second level if the voltage level from the integrator falls below the predetermined level;

second comparator means responsive to the signals representative of cylinder ignition for generating an output signal whenever the signal levels exceed a predetermined level;

And-gate means responsive to the signals from said first comparator means and said second comparator means for generating short pulses representative of cylinder ignition.

3. In an apparatus for analyzing the operation of a multiple cylinder internal combustion engine, improved means for detecting cylinder ignition signals, said improvement comprising:

means coupled to the engine for sensing signals representative of cylinder ignition;

comparator means responsive to the signals representative of cylinder ignition for generating an output signal whenever the input signal to the comparator means exceeds a predetermined amplitude level;

one-shot multivibrator means responsive to the signal from said comparator means for generating output signals varying in duration;

And gate means responsive to the output signals from said one-shot multivibrator and said comparator means for generating short pulses representative of cylinder ignition; and

means responsive to the pulses from said AND gate means for varying the R-C time constant of said one-shot multivibrator in relation to the frequency of the pulses from said AND gate means.