Method and apparatus for generating display waveforms im wasted spark ignition systems

• US 5,068,613 A
• Filed: 10/11/1988
• Issued: 11/26/1991
• Est. Priority Date: 03/17/1987
• Status: Expired due to Term

• Current Assignee: Snap-On Tools Company LLC (Snap-On Incorporated)
• Original Assignee: Sun Electronics Corp (Snap-On Incorporated)
• Inventors: Kreft, Keith A., Dikopf, Michael, Loewe, Thomas D.
• Primary Examiner(s): WIEDER, KENNETH A
• Assistant Examiner(s): Mueller, Robert W.
• Application Number:
  US07/256,168
• Time in Patent Office: 1,141 Days
• Field of Search: 324/379, 324/397, 324/384, 324/402, 324/399, 324/393, 324/394, 73/116, 73/119 R
• US Class Current: 324/379
• CPC Class Codes: F02P 17/04 dynamically
• CPC Class Codes: F02P 17/08 using a cathode-ray oscilloscope F02P17/06 takes precedence

Abstract

A method and apparatus of developing a stabilized power firing event signal for a cylinder in a wasted spark ignition system having pairs of complementarily connected cylinders, each with a spark plug connected to an opposite end of an independent ignition coil. The first and second firing event signals are developed for each spark plug upon firing of the ignition coil. The first and second signals are combined with like polarity in a summation circuit for eliminating common mode signal portions. The combined signal, which is now stabilized and accurately indicates spark duration, is used for capturing secondary ignition data and may be visually displayed for analysis.

Claims

1. A method of developing a stabilized firing event signal in a cylinder for a wasted spark ignition system wherein the spark plugs of a pair of complementary cylinders are fired simultaneously from opposite ends of an ignition coil secondary winding, comprising the steps of:

obtaining separate firing event signals from the spark plug ignition wires associated with the pair of cylinders;

sorting the firing event signals into first, power spark signals and second, wasted spark signals of like polarity;

combining the power spark signals and wasted spark signals together to eliminate common mode signal components therefrom; and

developing visual displays of power spark signals, wasted spark signals and combined power spark signals and wasted spark signals.

2. Apparatus for developing a stabilized firing event signal in a wasted spark ignition system comprising:

a first and a second cylinder;

first and second spark plugs associated with said first and said second cylinder, respectively;

a secondary ignition coil winding having its respective ends coupled to said first and to said second spark plugs;

pickup means for developing first and second firing event signals from said first and said second spark plugs upon firing of said ignition coil winding;

means for developing from said first and said second firing event signals, a power spark signal and a wasted spark signal of like polarity;

means for combining said power spark signal and said wasted spark signal to eliminate common mode signal components therefrom; and

means for displaying said power spark signal, said wasted spark signal and said combined power spark and wasted spark signals.

3. A method of developing a stabilized firing event signal for a cylinder in a wasted spark ignition system wherein the spark plugs of a pair of complementary cylinders are fired simultaneously from opposite ends of an ignition coil secondary winding comprising the steps of:

developing first and second signals from the firing events of the associated pair of cylinders; and

combining said first and second signals to eliminate common mode signal components therefrom.

4. The method of claim 3 wherein said developing step comprises the step of:

obtaining said first and second signals from the spark plug ignition wires associated with said pair of cylinders; and

wherein said combining step comprises the step of;

supplying said first and second signals with like polarity to a summation circuit.

5. The method of claim 4, further including the step of developing a visual display of said combined first and second signals.

6. Apparatus for developing a stabilized firing event signal in a wasted spark ignition system comprising:

a first and a second cylinder;

first and second spark plugs associated with said first and said second cylinder, respectively;

a secondary ignition coil winding having its respective ends coupled to said first and said second spark plug;

means developing first and second firing event signals from said first and said second spark plugs upon firing of said ignition coil winding; and

means combining said first and said second firing event signals to eliminate common mode signal portions.

7. The apparatus of claim 6 wherein said combining means comprise a summation circuit and means for supplying said first and said second signals to said summation circuit with like polarity.

8. The apparatus of claim 7 wherein said ignition coil winding is connected to said first and said second spark plugs by ignition wires and wherein the means for developing said first and said second signals comprise pickup means associated with said ignition wires.

9. The apparatus of claim 8, further including means for visually displaying the combined first and second signals.