IGNITION FAULT ANALYSER

• US 3,763,421 A
• Filed: 09/09/1971
• Issued: 10/02/1973
• Est. Priority Date: 09/09/1971
• Status: Expired due to Term

• Current Assignee: Arthur F. Glomski
• Original Assignee: Arthur F. Glomski
• Inventors: Glomski, Arthur F.
• Primary Examiner(s): Lynch, Michael J.
• Application Number:
  US05/178,891
• Time in Patent Office: 754 Days
• Field of Search: 324/15-17,122,133
• US Class Current: 324/395
• CPC Class Codes: F02P 17/12 Testing characteristics of the spark, ignition voltage or current testing of sparking plugs H01T13/60
• CPC Class Codes: F02P 2017/006 using a capacitive sensor

Abstract

A dynamic spark plug tester adapted for use in testing spark plugs installed on an operating engine. The tester includes a hand actuable clamp alternatively engageable with the high voltage input cable to the distributor associated with such engine or with individual high voltage cables connecting the distributor to respective spark plugs. The clamp incorporates a capacitive coupling element engageable with such cables and has a hand engageable handle portion which carries a compact housing in which test circuitry and an indicating lamp are contained. A ground cable connected to such circuitry is fixedly supported by the handle and terminates remotely from the handle in a ground clip which may be attached to the engine or vehicle frame for completing the tester circuit.

Claims

1. In a spark plug tester, the combination comprising:

clamp means for releasable securement to high voltage cable in circuit with a portion of the high voltage ignition circuitry of a spark plug ignited engine, said clamp means including at least one elongated leg;

ground means connectable to the ground side of said high voltage ignition circuitry and including a ground cable fixed to said clamp means;

means defining a test circuit electrically connected to said clamp means and to said ground cable and including indicator means for signaling a fault condition in said high voltage circuit of said engine, including a fault in one of the spark plugs; and

housing means fixed to said leg in offset and transversely extending relation thereto and enclosing said test circuit in fixed relation thereto.

2. The device of claim 1 in which said elongate leg has pick-up means at one end thereof for coupling to a high voltage cable of said engine ignition system and has deformable means adjacent the other end thereof for clamping one end portion of said ground cable in firmly fixed relation to said leg, said ground cable comprising an elongaTe insulated cable having a clip adjacent the other end thereof for attachment to means grounded with respect to the ground side of the spark plugs of said engine and said ground cable having an exposed electrical conductor extending toward said housing means, said electrical conductor being electrically connected to the clip.

3. The device of claim 1 in which said clamp means includes capacitive pick-up elements for clamping securement to said high voltage cable and said test circuit comprises unidirectional conducting means connected between said clamp means and said ground means for conducting in response to a voltage drop between said clamp means and ground means in one direction, a voltage drop in the opposite direction corresponding to a fault condition in said high voltage system, a discharge lamp connected across said unidirectional conducting means for ignition upon a voltage drop thereacross in said opposite direction, a capacitor connected in parallel with each of said unidirectional conducting means and said discharge lamp and forming, with said capacitive pick-up elements, a voltage divider for stepping down the voltage of said high voltage cable to a level useable with said discharge lamp.

4. The device of claim 3 in which said test circuit further includes a protective resistor directly electrically connected to said clamp means on one side thereof and connected to the cathode of said unidirectional conducting means, to said capacitor and to said discharge lamp on the other side thereof.

5. The device of claim 1 in which said clamp means comprises a further elongate leg, means pivotally connecting said legs intermediate the ends thereof for allowing opening and closing movement of an opposed pair of ends of said legs, an opposed pair of pick-up elements fixed on said leg ends, said pick-up elements each comprising a longitudinally curved elongate shell, the curvature of which corresponds at least approximately to the normal curvature of high voltage cable of said ignition system, said pick-up elements having opposed concave faces sized to firmly grip a high voltage cable of said ignition system to support said clamp means thereon and to electrically couple said clamp means to said high voltage cable to allow sensing of high voltage electrical signals passed by said cable.

6. The device of claim 1 including means located adjacent the opposite ends of said leg for securement respectively to such high voltage cable and to said ground cable, said housing means comprising a hollow body having an open end adjacent said clamp means and said ground cable and further having a flange extending beyond the open end of said hollow body, said flange contacting said leg intermediate the ends thereof and being fixed thereto.

7. The device of claim 1 in which said test circuit comprises a plurality of components interconnected with said indicator means and said housing means comprises a light transmissive hardenable mass within which said test circuit components are rigidly located, said indicator means comprising a discharge lamp in said mass adjacent a peripheral face thereof, whereby ignition of said discharge lamp is visible outside said housing means.

8. The device of claim 1 in which said housing means comprises wall means defining a hollow body having a closed end and an open end, said indicator means comprising a lamp, said test circuit including a resistor disposed in said housing means adajcent a portion of the wall means thereof and extending away from said closed end wall, said resistor having a first lead extending outwardly through said open end, said lead being electrically connected to said clamping means, said test circuit further including a capacitor having a first lead connected to the other lead of said resistor and extending substantially in parallelism and in spaced relation with said closed end wall and said lamp, said capacitor having second lead having at least a portion extending away from said closed end wall and along a furTher wall portion of said housing means in spaced relation to said resistor and out of the open end of said housing means for electrical connection to said ground means, a diode interconnected between said other lead of said resistor and said second lead of said capacitor, said lamp having a pair of leads connected respectively to said other lead of said resistor and said second lead of said capacitor, the portions of the interior of said housing not occupied by said resistor, diode, capacitor and lamp being filled with a light transmissive, hardenable compound for holding said circuitry fixedly in place within said housing means.

9. In a spark plug tester, the combination comprising:

clamp means for releasable securement to a cable in circuit with a portion of the high voltage ignition circuitry of a spark plug ignited engine, said clamp means comprising a pair of elongate opposed legs, means pivotally connecting said legs intermediate the ends thereof for allowing opening and closing movement of an opposed pair of ends of said legs, a pair of pick-up elements adapted for movement with said leg ends toward and away from each other, said pick-up elements each comprising a curved elongate shell, the curvature of which corresponds at least approximately to the normal curvature of high voltage cables of said ignition system, said shells being of substantially hemicircular cross section for defining a substantially circular cross section passage extending longitudinally through said opposed pair of pick-up elements, said pick-up elements being sized to firmly grip a high voltage cable of said ignition system to support said clamp means threon and to electrically couple said clamp means to said cable to allow sensing of high voltage electrical signals passed by said cable;

ground means connected to the ground side of said high voltage ignition circuitry and carried by said clamp means;

means defining a test circuit electrically connected to said clamp means and to said ground means and including indicator means for signaling a fault condition in said high voltage circuit of said engine, including a fault in one of the spark plugs; and

housing means fixed with respect to said clamp means for carrying said circuitry in fixed relation to said clamp means.

10. In a spark plug tester, the combination comprising:

clamp means for releasable securement to a cable in circuit with a portion of the high voltage ignition circuitry of a spark plug ignited engine;

ground means connected to the ground side of said high voltage ignition circuitry and carried by said clamp means;

means defining a test circuit electrically connected to said clamp means and to said ground means and including indicator means for signaling a fault condition in said high voltage circuit of said engine, including a fault in one of the spark plugs; and

housing means fixed with respect to said clamp means for carrying said circuitry in fixed relation to said clamp means;

said clamp means including at least one elongate leg and means located adjacent the opposite ends of said leg for securement respectively to a cable of said high voltage portion of said ignition system and to said ground means, said housing means comprising wall means defining a hollow body and closing one end of said body leaving the other end of said body open, said wall means including a flange extending beyond the open end of said housing means, said flange underlying said leg intermediate the ends thereof and including means for fixedly connecting said flange to said leg for supporting said housing means in offset and transversely extending relation to said leg.

11. The device of claim 10 in which said housing comprises means defining an opening in a portion of the wall means of said housing means adjacent said closed end thereof, said indicator means comprises a discharge lamp in said housing means adjacent said opening, whereby ignition of said discharge lamp is visible through said openIng outside said housing means, said test circuit includes a resistor disposed in said housing means adjacent a portion of the wall means thereof and extending away from said closed end wall, said resistor having a first lead extending outwardly of said housing means in spaced relation to said flange, said lead being electrically connected to said clamping means, said test circuit further including a capacitor having a first lead connected to the other lead of said resistor and extending substantially in parallelism and in spaced relation with said end wall and said lamp, said capacitor having second lead having at least a portion extending away from said closed end wall and along a further wall portion of said housing means in spaced relation to said resistor and out of the open end of said housing means above said flange for electrical connection to said ground means, a diode interconnected between said other lead of said resistor and said second lead of said capacitor, said lamp having a pair of leads connected respectively to said other lead of said resistor and said second lead of said capacitor, the portions of the interior of said housing not occupied by said resistor, diode, capacitor and lamp being filled with a light transmissive, hardenable compound for holding said circuitry fixedly in place within said housing means.