Title:
ENGINE IGNITION TEST DEVICE
United States Patent 3806796


Abstract:
Engine ignition test device includes serially-connected adjustable spark gap and lamp for connection in parallel to a portion of an engine ignition circuit. The adjustable spark gap comprises a fixed electrode and a pivoted movable electrode that swings away from the fixed electrode for gap adjustment. The movable electrode can be repositioned to compensate for wear. Test probes include a test connector for serial connection in high voltage ignition lines and a test sensor for detecting the external electric field on the high voltage ignition leads.



Inventors:
GOLDSTEIN R
Application Number:
05/242572
Publication Date:
04/23/1974
Filing Date:
04/10/1972
Assignee:
GOLDSTEIN R,US
Primary Class:
Other Classes:
324/122, 324/395, 324/397
International Classes:
H01T13/58; (IPC1-7): G01R13/42
Field of Search:
324/15-19,122
View Patent Images:
US Patent References:
3588679N/A1971-06-28Lewin
2746010Ignition system tester1956-05-15Feaster
2042009Electrical testing apparatus1936-05-26Levitt
1950052Motor analyzer1934-03-06Haskins
1914809Spark plug tester1933-06-20Konsted



Primary Examiner:
Lynch, Michael J.
Attorney, Agent or Firm:
Shapiro, Allan M.
Claims:
What is claimed is

1. An engine ignition test device comprising a test unit having a serially connected adjustable spark gap and a lamp, and a test connector serially connected to said adjustable spark gap, said lamp being visible exteriorly of said test unit, the improvement wherein said adjustable spark gap comprises:

2. The engine ignition test device of claim 1 wherein:

3. The engine ignition test device of claim 2 wherein:

4. An engine ignition test device comprising:

5. The engine ignition test device of claim 4 wherein:

6. The engine ignition test device of claim 4 wherein:

7. The engine ignition test device of claim 6 wherein:

8. The engine ignition test device of claim 7 wherein:

Description:
BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is directed to an engine ignition test device, particularly for testing the high voltage components thereof.

2. Description of the Prior Art

As spark ignition engines become more highly refined, and especially as it becomes desirable to reduce undesirable gaseous discharges from such engines, much new equipment has been developed for the diagnostic analysis of spark ignition engines. Perhaps the most highly refined and most universal piece of equipment for testing the electrical ignition components and system of a spark ignition engine is the oscilloscope, when properly equipped with suitable auxiliaries. Oscilloscopes specially fitted out for spark ignition diagnostics are presently known in the art. When equipped in this way, they can be connected to both the low and high voltage portions of the spark ignition system for analysis of point gap dwell and point resistance on the low voltage side, as well as coil voltage and spark condition in each of the spark plugs. These devices are complex and expensive. Certain high voltage diagnostics can be accomplished without resort to such expensive equipment.

High voltage spark gaps in parallel to the spark plugs in an internal combustion engine have been known. For example, Kovac U.S. Pat. No. 2,564,764 teaches the permanent installation of a fixed high voltage spark gap in parallel to the main high voltage coil lead to indicate to the driver existence of excessive voltage conditions, upon such a malfunction. Strauss U.S. Pat. No. 2,496,823 teaches an adjustable spark gap for use in ignition system testing on the high voltage side of the ignition coil. However, neither of these devices provides the information nor is sufficiently flexible or convenient to use as the engine ignition test device of this invention.

SUMMARY OF THE INVENTION

In order to aid in the understanding of this invention, it can be stated in essentially summary form that it is directed to an engine ignition test device which comprises a circuit including an adjustable high voltage spark gap serially connected to a lamp, the circuit being connectable in parallel to a portion of the high voltage section of a spark ignition engine ignition system.

It is an object of this invention to provide an engine ignition test device which is of economic construction and which is convenient and reliable to use in the testing of the high voltage portion of a spark ignition engine. It is a further object to provide a test device which includes an adjustable spark gap connectable in parallel to a portion of the high voltage system of a spark ignition engine. It is another object to provide a lamp in series with an adjustable spark gap so that, as the gap is adjusted, arcing thereacross can be observed in the series-connected lamp. It is a further object to provide an engine ignition test device which is convenient to use in a plurality of different tests in various portions of the high voltage system of an engine ignition. It is a further object to provide a test device which is easy to use in a plurality of different tests in determining the voltage condition by means of the adjustable gap which is adjusted to permit an arc to ground.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages thereof, may be understood best by reference to the following description, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of the engine test device of this invention, with part of the electric leads thereof broken away to indicate longer length thereof.

FIG. 2 is a rear elevational view of the main housing thereof, with a portion of the back cover broken away to show internal construction.

FIG. 3 is a section taken generally along the line 3--3 of FIG. 2.

FIG. 4 is a section taken generally along the line 4--4 of FIG. 2.

FIG. 5 is a side view, with parts broken away and parts taken in section, of the test connector structure which forms a portion of the engine ignition test device of this invention.

FIG. 6 is a side elevational view of an ignition coil, with the test connector applied thereto.

FIG. 7 is a side elevational view of a portion of a conventional distributor, showing the employment of the test connector of the test device of this invention, and this figure further showing the conventional spark plug and spark plug lead, with parts thereof broken away.

FIG. 8 is a structural schematic view of an ignition circuit for a spark ignition engine, with the circuit of the test device of this invention connected thereto.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The preferred embodiment of the engine ignition test device of this invention is generally indicated at 10 in FIG. 1. This comprises the test unit 12 which is connected by lead 14 to test connector 16. Test sensor 18 is used with test connector 16 for certain of the tests which the engine ignition test device 10 is employed to perform.

The engine ignition test device operates on the principle of connecting a neon indicator light in series with an adjustable spark gap and connecting this series combination in parallel with various elements of the high voltage portion of the spark ignition circuit equipment of the internal combustion engine to be tested. The test unit 12 contains the neon light and the adjustable spark gap. Test unit 12 comprises a housing 20 which has the front wall 22 from which side walls 24 and 26 and end walls 28 and 30 depend to enclose interior space 32. The interior space 32 is divided by interior wall 34 which extends at least partway across the space 32. Back 36 covers the interior space 32 and may be removably secured if access to the equipment contained therein is required. Since the test device 10 is to be used at voltages corresponding to the high voltage side of spark ignition internal combustion engines and an equivalent spark is to be contained within housing 20, housing 20 is preferably formed of high dielectric strength material, such as filled phenolic or many of the modern injection moldable thermoplastic synthetic polymer composition materials. Back 36 is preferably similarly formed of high dielectric strength material.

Electrode post 38 (seen in FIGS. 2 and 4) is mounted through interior wall 34 and is secured thereby with a shoulder on one side of wall 34 (FIG. 2) and nut 40 on the other side of the wall. Thus, electrode post 38 is fixed in position. Electrode post 38 has a larger diameter portion 42 which has the shoulder which engages against interior wall 34, and has a smaller diameter portion 44 extending therefrom into space 32. These two portions are separated by stop shoulder 46. Both portions are conveniently cylindrical for ease of manufacture, and stop shoulder 46 is conveniently planar, and positioned normal to the axis of electrode 38. On the other hand, the smaller diameter portion 44 may not be of uniform diameter, but may be contoured for control of the spark gap, as is subsequently described; in any event, electrode portion 44 is preferably a surface of revolution about the central longitudinal axis of electrode 38 for purposes of ease of manufacture. Electrode 38 serves as one of the electrodes of the adjustable spark gap within test unit 12.

The other electrode of the adjustable spark gap is formed by rod 48. As seen in FIGS. 2, 3, and 4, rod 48 passes through an opening near the end of adjustment post 50. Adjustment post 50 passes through and is rotatable relative to the front wall 22 of test unit 12 and carries adjustment knob 52 on the front thereof. Adjustment knob 52 is secured to adjustment post 50 for rotation thereof so that the angular position of knob 52 corresponds to the angular position of post 50. Adjustment knob 52 carries reference mark 54 which cooperates with indicia 56 secured to the front wall 22 to indicate the relative rotary position of adjustment post 50 and relative angular position of rod electrode 48.

Compression spring 58 is engaged around adjustment post 50 and carries washers 60 and 62 on the inner and outer ends thereof. Washer 62 engages against rod electrode 48 to releasably restrain rod electrode 48 in its longitudinal direction. When adjustment of rod electrode 48 is desired, it is moved against shoulder 46, washer 62 is depressed against spring 58, and rod electrode 48 is pressed to the left (as seen in FIGS. 2 and 4) so that its firmly engages smaller diameter portion 44, and thereupon washer 62 is released to retain rod electrode 48 in its proper longitudinal position. In this position, adjustment knob 52 is secured to its post 50 in an appropriate angular position so that reference mark 54 indicates zero spark gap, and therefore zero voltage, on indicia 56. From this construction, it is seen that, as the knob is moved, the outer end of rod electrode 48 swings away from shoulder 46 and increases the gap between the outer end of rod electrode 48 and the smaller diameter portion 44. Thus, the adjustable spark gap is increased. From this geometry it is seen that the adjustable spark gap increases as the sine of the angle, because the outer end of the rod electrode 48 describes a circular path in cooperation with the cylindrical smaller diameter 44. If a function other than the sine function is desired, the smaller diameter portion 44 can be appropriately shaped to produce the desired result. For practical purposes, the sine function is a desirable relationship, and indicia 56 indicate voltage values related to the spark gap.

Neon lamp 64 extends through an opening in the front wall opening 22 of test unit 12 so that it is visible from the front of the unit. It is protected by shield 66, which protects it from mechanical damage and provides a shade to aid in its observation in brightly lighted environments. Socket 68 carries lamp 64 and is secured to the side of interior wall 34. Neon lamp 64 is preferably the type where both electrodes are visible so that polarity can be observed.

Going to the wiring interconnection of the test unit 12, ground wire 70 has a connector, such as alligator clip 72, for connection to an electrical ground in the high voltage portion of the spark ignition circuit. Ground wire 70 enters test unit 12 through end wall 28. Interiorly of end wall 28 it is connected under nut 74, which secures socket 68, and which serves as one of the socket terminals. From the other terminal side of socket 68, electrically on the other side of neon lamp 64, wire 76 connected neon lamp 64 to post 50. The end of wire 76 carries a flat ring-type wire terminal which is positioned beneath washer 60 to maintain good electrical contact. Washers 60 and 62, spring 58, and post 50 are all metallic to provide electrical connection through to metallic rod electrode 48. Test lead 14 is connected under nut 40 by a similar wire terminal and extends out of test unit 12 through end wall 28.

Test lead 14 interconnects the test unit 12 with test connector 16. As is seen in FIGS. 1 and 5, the outer end of test lead 14 is directly connected, as by swagging or soldering, to the metallic body 80 of the test connector. Socket 82 is formed in the upper end of the body for connection of standard male connector high voltage ignition lines thereto. The lower end of body 80 has a nose 84 thereon and metallic leaf spring 86 is secured to the nose. These parts are dimensioned so that they can enter into the standard female socket in high voltage ignition equipment. Resilient sleeves 88 of high dielectric strength material are positioned around the major portion of body 80 to permit its handling and to prevent stray arcs.

Test sensor 18 comprises a U-shaped metallic sensor 92 which has an open sided longitudinal channel 94 extending the length thereof. The channel 94 is of sufficient width to be able to embrace the external insulation of a high volt ignition line. It has socket 90 attached thereto in which the male connector on test connector 16, comprised of springs 86 on nose 84, can be inserted. Test sensor 18 is of metallic material so that, when it is connected in that way, the sensor is electrically connected to test unit 12.

FIG. 8 schematically indicates the arrangement of the conventional ignition circuit in a spark ignition internal combustion engine. It shows an ignition coil 96 having a battery 98 and breaker points 100 serially connected to the low voltage turns in the coil. Conveniently, one side of that system is grounded. When points 100 are closed, current builds up in the low voltage circuit. When they are opened, the magnetic field collapse causes a high voltage impulse in the high voltage coil of ignition coil 96. This high voltage pulse appears between ground, to which one side of the high voltage coil is connected, and a female terminal in tower 102 of coil 96. Coil wire 104 conventionally connects the coil tower 102 to tower 106 on distributor cap 108. The distributor cap 108 internally contains a rotor which passes adjacent a plurality of contacts, each of which is connected to a different spark plug 110 through plug wire 112. The spark plug 110 has a spark gap, the other side of which is connected to ground, to complete the high voltage circuit. While one spark plug is illustrated in each of FIGS. 7 and 8, it is understood that there are a plurality of such spark plugs and a plurality of such spark plug wires, in accordance with the plurality of connections on the top of the distributor cap 108. In the usual automotive and spark ignition internal combustion engines, there are four to eight spark plugs, one for each cylinder, and the same number of plug wires and sockets for connection of the plug wires into the distributor cap.

FIGS. 6 and 8 illustrate the method of connection of the engine ignition test device 10 into an ignition circuit for the initial and principal tests. In this position, the test connector 16 is plugged into the female terminal in the top of tower 102 on ignition coil 96, while the coil wire 104 is plugged therein. Knob 54 is adjusted so that the spark gap between electrodes 38 and 48 is fairly large. It is preferred that the indicia 56 indicate the voltage at which arcing will occur across the gap between the electrodes, to thus indicate the state of the equipment in parallel to it. On the first test, it is assumed that the spark plugs 110 have been determined to be in good adjustment and condition, and the points 100 similarly determined to be in good condition and adjustment. Preferably both the spark plugs and points have been replaced and set.

The adjustable spark gap 114 between electrodes 38 and 48 is adjusted so that it will not arc across until about 30 kv (kilovolts) are applied thereto. While particular values of voltage are given in this specification to represent corresponding gap dimension, it is understood that they are examples of what is expected in present-day automotive equipment. Different values with change in design and with different applications may suggest different numerical values than those set forth herein.

Thereupon, the engine is started and will run normally and properly if all the equipment is in good condition. Knob 54 is turned slowly to reduce the gap 114 between electrodes 38 and 48 and, if the gap between the rotor and the fixed terminals in distributor cap 108 are correct, and if all connection wires are in good condition, the light 64 will not flash until the gap 114 is closed to about 10 kv or slightly less. This is the normal arc voltage of the series connection of the rotor gap and spark plug gap when they are both in tolerance. When the battery 98 and spark coil 96 are correctly installed, the illumination of one side of the light 64 starts flashing due to a reduced gap 114, the engine stalls indicating that the parallel circuit through gap 114 is arcing so that the spark plugs 110 cannot spark. This is the usual condition indicating good condition of the equipment, when the lamp 64 starts flashing and the engine stalls at about 10 kv. When the coil and battery are correctly installed, provided the engines have the same ground polarity (negative in most American cars) the gap is then reduced the same electrode and the light will flash on. This electrode is arbitrarily called the negative ground electrode. If the coil or battery is installed with wrong polarity the other or positive electrode will flash on.

If the lamp 64 starts flashing at a higher arc voltage value than 10 kilovolts, as the gap 114 is reduced toward 10 kilovolts but the engine does not stall until about 10 kilovolts is reached, this indicates that one or more of the plug wires 112 is defective, because the higher voltage is applied across gap 114 at some distributor rotor positions.

To determine which of the wires 112 is bad due to high resistance of the conductor, test connector 16 is removed from the top of coil 96, and the coil wire 104 is plugged directly into the female terminal in tower 102. With the connections made in this way, the connections are in the usual, non-test arrangement. Nose 84 with its leaf spring connectors 86 are plugged into receptacle 90 in test sensor 18. The gap 114 is set to zero so that the electrodes 38 and 48 are in contact with each other. With the engine running, test sensor 18 is successively placed around each one of the spark plug wires 112. For those wires 112 which have the normal resistance value, the lamp 64 will glow only very faintly, or not at all. If the dial is turned to 1 or 2 kilovolts, the glow will disappear. If the wire is defective due to high resistance, the light will glow more brightly. If the dial is turned to 1 or 2 kilovolts, the light flash brightly at both electrodes. Modern cars use carbon core resistance spark plug wires. The carbon sometimes fails inside the wire by mechanical damage or burning, thus causing a break in the continuity of the wire, and therefore causing high resistance.

The engine ignition test device 10 can also be employed to determine the condition of ignition coil 96. In this test, test connector 16 is installed in the terminal on top of coil 96, as shown in FIG. 6, and the coil wire 104 is connected, also as shown in FIG. 6. One spark plug wire is removed and the gap 114 is adjusted so that it requires about 30 kv to arc across, and the engine is started. If the lamp 64 flashes, it indicates good condition of coil 96. If the lamp 64 does not flash, dial 52 is turned to reduce gap 114, and if the coil 96 does not produce sufficient voltage to arc across gap 114 by the time the gap is reduced to a dimension corresponding to about 20 kv, the coil 96 is below specification. The value of 25 kv is moderately good, and 20 kv is fair, but at this value the coil quality is marginal.

In the next test, the test connector 16 is plugged into the terminal on the top of coil 96, as shown in FIG. 6, and the coil wire 104 is inserted in the top of the test connector. With the gap 114 adjusted to about 25 kv, the engine is started. The gap is slowly reduced. If the light flashes on and the engine stalls above about 10 kv, there is excessive resistance common to all spark plug connections. There are two things common to all of the spark plug circuits. The first is coil wire 104, and the second is the gap between the rotor and the fixed contacts within distributor cap 108. In determining the condition of wire 104, the test connector 16 is removed from the top of coil 96 and is placed in the center terminal of distributor 108, as shown in FIG. 7. Coil wire 104 is connected to the tower coil 96 and to test connector 16. This takes wire 104 out of the test. Thereupon, the gap 114 is adjusted to about 30 kv, and the engine is started. Knob 52 is slowly adjusted to reduce gap 114, and if lamp 64 does not flash and the engine does not stall until about 10 kv is reached, it is shown that the coil wire 104 is defective in having excessive resistance. However, should that wire prove to be in tolerance, test of the rotor gap is made. This is made by placing test connector 16 in the female socket where spark plug wire 112 is normally plugged into distributor cap 108, and the wire 112 is plugged into the top of the test connector 16. This removes the rotor gap from the test. Coil wire 104 is connected into its usual sockets. With the gap 114 adjusted to 30 kv, the engine is started. Thereupon, knob 54 is turned to reduce gap 114. If the light 64 flashes on above 10 kv, the problem is excessive rotor gap within the distributor cap. Replacement of either or both the rotor and cap will solve this gap problem.

In some circumstances, an individual spark plug wire may be shorted to ground. To determine this condition, the test connector 16 is preferably placed in the center connector of the distributor cap 108, as shown in FIG. 7, but it may be placed in the high voltage coil connection, as shown in FIG. 6. The gap 114 is set for a value between the arc voltage value of the unconnected coil and the normal arc voltage of the system, e.g., a value of the gap 114 from 15 to 20 kv is useful. The engine is started and, if all of the tests described above have shown the equipment to be normal, the lamp 64 will not flash. As the engine is running, the spark plug wires 112 are successively removed and replaced from their corresponding spark plugs. When a wire is removed, if the wire is in good condition, lamp 64 will flash. Each wire is successively replaced and the next is removed. If any one of the spark plug wires is shorted out between its ends, the removal of the wire from the plug will not cause flashing in the lamp. Thus, grounding of that wire between the distributor cap and the spark plug is indicated.

By these tests, the engine ignition test device is employed to test a number of different characteristics of the high voltage portion of the ignition system in the spark ignition internal combustion engine.

While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.