Apparatus for measuring engine timing independent of speed

• US 4,092,585 A
• Filed: 05/03/1976
• Issued: 05/30/1978
• Est. Priority Date: 05/03/1976
• Status: Expired due to Term

• Current Assignee: Sun Electric Corp (Snap-On Incorporated)
• Original Assignee: Sun Electric Corp (Snap-On Incorporated)
• Inventors: Bovenlander, Johannes P.
• Primary Examiner(s): Krawczewicz, Stanley T.
• Application Number:
  US05/682,381
• Time in Patent Office: 757 Days
• Field of Search: 324/16 T, 324/15, 73/118
• US Class Current: 324/392
• CPC Class Codes: F02B 1/04 with fuel-air mixture admission into cylinder
• CPC Class Codes: F02P 17/06 using a stroboscopic lamp

Abstract

The disclosure describes improved apparatus for creating a delay for stroboscopes which corresponds to a fixed rotational angle of an engine and is independent of the rotational speed of the engine. The delay is created by charging a capacitor by means of a first current source and discharging the capacitor by means of a second current source.

Claims

1. Engine timing measuring apparatus for an engine having a chamber, a member movable in the chamber, combustion means for creating the combustion of fuel in the chamber so that the member is driven with respect to the chamber and an indicia to indicate the relative position of the chamber and the member, said apparatus comprising:

lamp means for illuminating the indicia in response to a strobe signal;

trigger means for generating a trigger signal in response to the operation of the combustion means to create the combustion of fuel in the chamber;

means for storing a variable timing voltage;

reference means for generating a reference voltage, said reference voltage being fixed during normal operation;

control means responsive to each trigger signal for altering the timing voltage in a first direction at a first predetermined rate until the timing voltage attains a predetermined relationship with respect to the reference voltage, for generating a strobe signal each time the timing voltage attains the predetermined relationship with respect to the reference voltage, and for altering the timing voltage in a second direction opposite the first direction at a second predetermined rate from the time the timing voltage attains the predetermined relationship with respect to the reference voltage until the next trigger signal is generated;

adjustment means for altering the first predetermined rate until the lamp means illuminates the indicia in a predetermined position; and

scale means connected to the adjustment means for displaying the degree of movement of the member relative to the chamber between the time the trigger signal is generated and the time the lamp means is illuminated, whereby the degree of movement is accurately displayed irrespective of changes in speed of the member relative to the chamber.

2. Apparatus, as claimed in claim 1, wherein the means for storing comprises a capacitor.

3. Apparatus, as claimed in claim 2, wherein the control means comprises:

a first current source for altering the timing voltage in the first direction; and

a second current source for altering the timing voltage in the second direction.

4. Apparatus, as claimed in claim 3, wherein the control means further comprises:

comparator means for generating a reset pulse when the timing voltage attains the predetermined relationship with respect to the reference voltage;

flip flop means for producing an output signal which switches to a first state in response to each trigger signal and switches to a second state in response to each reset pulse; and

generating means for generating the strobe signal each time the flip flop means output signal changes from the first state to the second state.

5. Apparatus, as claimed in claim 3, wherein the adjustment means comprises a potentiometer connected to the first current source.