PORTABLE AUTOMOTIVE SPARK VOLTAGE TESTER

• US 3,743,922 A
• Filed: 06/07/1971
• Issued: 07/03/1973
• Est. Priority Date: 06/07/1971
• Status: Expired due to Term

• Current Assignee: Nicholas G. Festos
• Original Assignee: Nicholas G. Festos
• Inventors: Festos, Nicholas G.
• Primary Examiner(s): Rolinec, Rudolph V.
• Assistant Examiner(s): Karlsen, Ernest F.
• Application Number:
  US05/150,365
• Time in Patent Office: 757 Days
• Field of Search: 324/19,16R,17,119,15,18
• US Class Current: 324/399
• 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 circuit for testing spark voltages in internal combustion engines or similar devices wherein the circuit capacitively samples the voltage of an in situs spark plug of an internal combustion engine by shunt-rectifying, filtering, and applying it to a direct current meter for visual indication.

Claims

1. A portable internal combustion engine spark plug testing apparatus for visually indicating the intensity of the spark of a discharging spark plug in an internal combustion engine while the spark is firing during the continuing operation of the engine, comprising:

a. a circuit having a positive lead provided with means for connection to an engine mounted and operating spark plug lead to be tested and a negative lead provided with means for connection to ground, b. a direct current meter in said circuit for visually indicating the voltage of the spark of said plug as it is being fired during operation of the engine, c. a diode having a cathode circuit and an anode circuit connected respectively to said positive and negative leads for rectifying the current from the spark plug from alternating to direct, d. a filter connected in the positive lead of said circuit between said diode and said direct current meter and including a choke in said positive lead and a by-pass condenser connected in shunt with said direct current meter for filtering the direct current to the direct current meter, e. a resistor for controlling the voltage of the rectified current as it passes through said meter so the same will have a high degree of sensitivity for an accurate reading of the intensity of the voltage of the plug being tested, f. including a capacitive pickup clip for mounting in the spark plug lead, and g. wherein said means provided by said positive lead for connection to the engine mounted and operating spark plug lead comprises a probe housing the diode and the choke of the circuit, said means provided including a connector adapted to be attached to the capacitive pickup clip mounted upon the spark plug lead of the spark plug to be tested.