USRE26163E

USRE26163E - Engine parameter analyzer

Info

Publication number: USRE26163E
Authority: US
Priority date: 1958-03-11
Publication date: 1967-02-28
Also published as: GB897651A; US2986032A; DE1143650B

Description

Feb. 28, 1967 B. F. w. HEYER ENGINE PARAMETER ANALYZER 3 Sheets-Sheet 1 Original Filed March 11, 1958 E @Samb E Cmmwm Q0., 59m/gw) A6804 gli #1112.9

ATTORNEY mmf. E 2

Feb. 28, 1967 B. F. w. HEYER Re 26,163

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BY/ g f fznsswa' fC/4ans ATTORNEY United States Patent Otilce Re. 26,163 Reissued Feb. 28, 1967 26 163 ENGINE PARAMETER ANALYZER Benjamin F. W. Heyer, Greenwich, Conn., by The Marquette Corporation of Golden Valley, Minn., a corporation of Delaware, assignee, assignor to Marquette Corporation, a corporation of Delaware Original No. 2,986,032, dated May 30, 1961, Ser. No.

720,688, Mar. 11, 1958. Application for reissue Aug.

12, 1965, Ser. No. 480,836

18 Claims. (Cl. 73-116) Matter enclosed in heavy brackets appears in the original patent but forms no part of this reissue specification; matter printed in italics indicates the additions made by reissue.

My invention relates to a combustion engine analyzing system, and more particularly to method and apparatus for electronically determining the relative contribution of each cylinder to overall performance of an engine.

In accordance with the present invention, a disabling action, is derived from the engine at a rate proportional to the speed of the engine crankshaft and in a definite phase relation thereto, this disabling action being used to cause by electronic means any desired cylinder or cyl inders of the engine to become inoperative. By selectively rendering any desired cylinder inoperative while the engine is still running, and without affecting the operation of the other cylinders, an analysis of the resulting engine performance enables ready determination of the contribution of a particular cylinder. This lanalysis retlccts either individually, or as compared to other cylinders of the engine, mechanical operating conditions within the cylinders, heretofore obtainable in crude fashion only, with the time consuming and unwieldy compression test and/or mechanical or manual ignition shorting devices.

[Another] An object of my invention is to provide an improved method of determining the relative contribution of cach cylinder to `overall performance of a combustion engine, by selectively rendering any desired cylinder ecctive/y inoperative through electronic means while the engine is running, and thereafterwards annlyzing the resulting engine performance whereby the said contribution of a particular cylinder as compared to other cylinders is readily determined at a glance.

Yet another object of my invention is to provide an improved method of determining the relative contribution of each cylinder to overall performance of a combustion engine, by selectively disabling electronically the cylinders one or more at n time, simultaneously measuring the change in [the engine parameters, i.e., performance output including:] mi engine parameter such as speed, vacuum, etc., as each of the cylinders is disabled, and then identifying such measurement with the specific cylinder or cylinders so disabled.

Still another object of my invention is to provide an improved combustion engine analyzing system wherein a trigger pulse is derived from one spark plug of the engine in such manner that the impulses occur at a rate proportional to engine r.p.m., said impulses being used directly or in combination with either electronic time delay measurement, electronic phase measurement, or an electronic engine events counting system to cause any desired cylinder or cylinders to become inoperative.

A further object of my invention is to provide improved combustion lengine analyzing systems for determining the contribution of each cylinder to overall performance of the engine wherein any desired cylinder is selectively rendered inoperative while the engine is running, by preventing ignition in one or more cylinders through electronic means, the cylinders ibeing selected by electronic time measurement, electronic numerical counting, or electronic phase measurement from the `beginning of a cornplete engine cycle to the position Iof the disabled cylinder or cylinders to be disabled in the firing order of the engine.

Yet a further object of my invention is to provide an improved internal combustion engine analyzer constructed and arranged whereby an analysis of the mechanical condition of an engine can be accomplished in a matter of a few minutes, and without the necessity of physically sorting out spark `plugs either at the distributor cap or at the plugs and avoiding the necessity of attaching mechanism or mechanical appurtenances such as adaptors, cams, shafts or complete transmisison systems for recording instruments.

With these and other objects in view, which may be incident to my improvements, the invention consists in the parts and combinations to be hereinafter set forth and claimed, with the understanding that the several necessary elements, comprising my invention, may be varied in construction, proportions and arrangement, without departing from the spirit and scope of the appended claims.

By way of clarification the following definitions prevail in the ensuing description:

(a) Complete engine cycle is: All engine events occurring from the ignition of a given cylinder until just preceding the next succeeding ignition of said given cylinder.

(b) "Phase is the relation in angular degrees between engine crank shaft position and ignition events selected for disabling.

(c) Disabling device herein shall include a device which renders the ignition of a given cylinder or cylinders inoperative.

(d) Time herein shall be the elapsed time between the commencement of a complete engine cycle and the occurrence of the ignition event selected for disabling.

(e) Count is [in] the number of ignition events 0ccurring between commencement of a complete engine cycle and the ignition event selected for disabling.

(f) Electronic or electronically, as used herein, shall `be defined as embracing devices in the art which have as components thereof either electron tubes or solid state devices, performing similar functions as electron tubes.

In order to make my invention more clearly understood, I have shown in the accompanying drawings [a] means for carrying the same into practical effect, without limiting the improvements in their useful applications to the particular constructions, which, for the purpose of explanation, have been made the subject of illustration,

In the drawings:

FIGURE 1 illustrates one embodiment of the present invention, the arrangement of the components and associated circuits being shown schematically;

FIG. 2 is a view of the `voltage waveforms at [the grid of one of the triodes of the trigger and time delay system of] various points in the circuit as illustrated in FIG. 1;

FIGS. 3.a and 3b are diagrammatic views of modified systems using various types of point shunting .and synchronizing units; and

FIG. 4 is a diagrammatic representation of the relation between engine crankshaft position and phase, time, and count [J shown illustrativey in a six cylinder, four-cycle engine.

Referring to the drawings, and more particularly to FIG. 1, there is shown one embodiment of the present invention wherein an electrical pulse is derived from the high tension ignition pulse to a spark plug of a combustion engine cylinder 1, which pulse activates the time delay circuit with a selectable delay, as will be described more fully hereinafter. Activation of the time delay circuit causes a thyratron V4 to become conductive to any suitable applied positive pulse for a short length of time,

at a selectable time after occurrence of the No. 1 cylinder ignition pulse. By making the selectable time delay equal to approximately the time between normal firing time of this cylinder and another cylinder N, not shown, the thyratron V4 is made conductive at the tiring time of cylinder N, and of Cylinder N only, and means are provided whereby the conducting thyratron disables the ignition of said cylinder, thereby rendering it inoperative. This is accomplished by shunting the breaker points in the ignition [coil] system by the thyratron. When the points are open, the thyratron conducts, [instead of the points] thereby preventing rapid change of magnetic tiux in the ignition coil and consequent ritzg of the spark plug.

lt will thus be seen that any desired cylinder, except No. 1 can be disabled. To disable this cylinder by setting the time delay to zero is not a solution since an ignition pulse must be present in order to initiate the time delay circuit. Setting the time delay equal to one complete engine cycle causes only even occurrences, that is to say` 2nd, 4th, 6th, etc. [having no previous initiation pulses] This is obviously the ease since the pulse from No. l plug can, if the time delay is set to equal one complete engine cycle, Cause No. I plug to be disabled on the second cycle. Due to the disal'iling7 of the plug, however, this pulse would not be available to disable the plug on the third cycle. Since the No. l plug would again be operative, it would be available one cycle later to disable the plug7 on the fourth cycle, etc.

In order to permit cylinder No. 1 to be shorted on all [fittings] rings, a special pulse generating circuit is employed in the cathode circuit of the shorting thyratron to generate a trigger pulse each time cylinder 1 is shorted, thus taking the place of the pulse ordinarily derived from the high tension lead of the cylinder, and allowing the time delay circuit to be self-triggering. This self-triggering pulse can also be used to synchronize Oscilloscopes or other auxiliary equipment such as tachometers, timing lights` and the like, which will stay in synchronism with the engine even though the normal synchronized pulse from the high tension lead is no longer present. For ignition systems having the hot" breaker point negative with respect to ground, for example, those with the plus terminal of the battery grounded, a suitable transformer is used to reverse the polarity so that a positive pulse is applied to the thyratron plate.

Reference again being had to FIG. l, the thyratron V1, which controls the cycle of operations, includes a cathode 10a, a control grid 10b, a shield grid 10c, and anode 10d contained within an envelope 10. The control grid and cathode are connected through an input system to a trigger source such as the ignition circuit of a combustion engine connected at terminals 11 through condenser C2 and resistor R10. The output system of the thyratron V1 is powered from a direct current source connected to terminals l2 and' I3, terminal l2 being7 at ground potential and [where] the positive side of the source which may be 280 volts` eg., [connects] being connected to terminal 13 leading through resistance R1 and a shunt path to ground containing condenser C1 and constituting a distributing path for potential to the anodes of the several tubes embodied in the circuit. The anode potential is supplied to plate 10d of the thyratron V1 through the adjustable resistors R2 where adjustable tap 14 movable thereover connects through resistance R7 to the plate circuit of thyratron V1 and through resistance R6 to the plate 10d, and a condenser C3 is connected between anode 10d and cathode 10a, which, as shown, is at ground potential.

The output circuit of the thyratron V1 contains a series path which includes a pair of resistances R11 and R12 having [a mid-tap] an intermediate tap 15 therebetween and connected in a series through another pair of resistances R11, and R19, having a mid-tap 16 therebetween. The end of resistance R11 connects with plate 10d through resistance Re while the end of resistance Rm connects with the cathode 10a of the thyratron V1. The resistances R18 and R19 are shunted by a condenser CG, and constitutes part of the voltage divider system for rendering the thyratron V1 nonconductive. The mid-tap 16 connects to a point 17 intermediate condenser C2 and resistance R10 in the input circuit of the thyratron. The direct current source connected to terminals l2 and 13 also has n further terminal connected to a point negatire with respect to ground. [The] This negative side of the voltage source [connected to terminals 12], which may he at 280 volts as shown in the drawing, connects through the resistance R11 to the point 18 intermediate the two sets of series connected resistances R11-R11 and R111-R111- The resistances R11-R12 serve as a network for biasing the control grid 2Gb of the high MU tube Vg which contains cathode 20a, the control grid 20h and the plate 20c wit/tin an envelope 20, The input circuit to high MU tube [20] V2 connects between tap l5 [and] between resistances R11 and R12 and ground indicated at 2l, and the plate potential for tube [20] V3 is supplied from the positive distributor bus 22 through resistance R11. The output circuit of high MU tube [20] V2 connects through condenser C1 to the control grid 23h ofthe cascaded high MU tube [23] V3 housed within an envelope Z3 containing cathode 23a connected to ground 2l and anode 23e connected through resistance R9 to the positive distributor bus 22. The input circuit of high MU tube [23] V1 has the bias thereon controlled through a selector, [for the number of cylinders of the engine to be] which is adfustetl in accordance with the test Conditions such as the number of cylinders in the engin@ being7 tested, comprising a switch S1 operative over contacts 24, 25. and 26 for selectively including resistanccs R3, R1, or R5, in circuit between the positive distributor bus 22 and control grid 23h of high MU tube [23] V3.

The switch S1 permits the selection of the time period over which the thyratron V4 can conduct. ln the case of a four-cylinder engine, this time period can be made, e.g., twice as long as for eight-cylinder engines, thus requiring no change of adjustment of resistance R2 for greater change in revolutions per minute of four-cylinder engines as compared to eight-cylinder engines. The output of high MU tube [23] V3 is bridged by a condenser C5, and includes a pair of resistances R13 and R14 connected in series with a mid-tap 27 therebetween and connected between the plate 23C and the negative side of the high potential source connected to terminals 12. The resistances R13-R11 serve as a voltage divider for the control grid of a thyratron V4 through a resistance R15.

The thyratron V1 includes cathode 28a. control grid 28h, shield grid 28e, and anode 28d, within an envelope 28. The [input] Cathode circuit to thyratron V4 is completed through the primary winding 29 of transformer T2 which connects to ground 21[, the input circuit includa ing]. The grid circuit of thyratron V4 includes resistance R15 connected to tap 27 in the voltage divider circuit R13-R11. Transformer T2 includes a secondary winding 30 connected to ground at one end and connected at the other end through a switch S1 for opening and closing the circuit through condenser C7 leading to the indicator trigger of the oscilloscope connected to output terminals 31. When the switch S1 is closed, the self-generated trigger pulse can thus be used to cause thyratron V4 to conduct on both even and odd cylinder No, 1 tirings, since the pulse applied to the indicator trigger of the oscillo- Scope, by reason of the Conventional interconnections between the oscilloscope ana' the ignition circuit connected at terminals Il, Causes the self-generated trigger pulse to be applied to the input of tuhe V1 to produce a pulse during the cycle that the No. l plugI is disabled. Thus, although the No. l plug is disabled, the pulse generated in secondary 30 causes thyratron V4 to Conduct one engine cycle later, thereby insuring that the thyratron V4 fires each cycle.

The output circuit ol the thyratron V1 extends from anode 28d through a momentary break switch S3 and to the polarity selector S3 [which]` The momentary break switch S2 is employed to disable the thyratron V4 when it is desired to temporarily observe engine operation under normal conditions with all cylinders tiring. The polarity selector S3 permits operations with either polarity at the breaker points of the engine, thus enabling the analyzer to meet different conditions encountered in the testing of engines of different makes. The polarity selector S3 is operative over

selector contacts

32, 33, 34, and 35. Contact 32 connects through switch S5 in the circuit to the hot breaker points connected t terminals 36. Contact 33 connects through auto-transformer T1, including primary and secondary windings in series with a tap 37 therebetween. Contact 34 connects to one end ot resistance R15 which connects through the primary Winding 29 of transformer T2 to ground 21 for effectively shunting the said primary winding whereby the breaker points with hot point positive are effectively shorted or `shunted by connecting them directly in parallel with a series combination of thyratron V1 and the primary transformer T2 in parallel with resistance R15, the thyratron anode voltage being the voltage across the breaker points at the instant they open.

Contact 35 connects to tap 37 in the auto-transformer T1. For breaker points with hot point negative, the `points are shunted by connecting them in parallel with the primary of auto-transformer T1, the secondary of which is shunted by a series combination of thyratron V.1 and the primary winding of transformer T2 and transformer T1 thus reversing phase of the applied anode voltage. Tlurs a positive voltage is applied to the anode even though the breaker point voltage is negative with respect to ground. Transformer T1 has sufcient primary inductance to otier only small loading with respect to the points, when the thyratron is non-conducting. and yet has sufficiently low resistance and coupling to heavily shunt the points when the thyratron is conducting. The transformer T2 has a primary winding 29 which is of very low inductance and resistance, thus offering onlyv a very small series impedance.

The selective shunting of breaker points indicated at 36 permits an analysis to be made of all the cylinders of the engine which I have indicated at P4 by reference symbols 1-6, for example.

[ln the operation of the analyzer of my invention, a suitable trigger pulse derived from the high tension lead of #l cylinder, eg.. is applied to the grid 10b of the thyratron V1 through terminals 11 for a time which renders thyratron V1 conductive until condenser C3 is diS- charged. The tihyratron V1 is normally biased so as to `by nonconducting by voltage divider R12-R12. Immediately after discharge, condenser C3 is charged positively by current flowing through resistances R2 and R1, and] OPERA TI ON In the absence of a pulse from terminals l1, the thyrotron V1 is nol'mally biased by voltage divider R18-R19 so as to be nonconductive. Because of condenser C3 being connected between the positive distributor bus 22 and ground through resistors R2 and R7, a charge is maintained across condenser C 5 of such polarity that its upper terminal connected to ano-de `d of thyratron V1 through resistor R6 is positive with respect to its lower terminal connected to cathode 10a, which is at ground potential. When a suitable trigger pulse derived from high tension lead of No. l cylinder, eg., through terminals Jl, is applied to the grid 10b of the thyratron V1, the thyratron V1 becomes conductive. The thyratron V1 remains conductive until condenser C5 has diS- charged through resistor R5 and thyratron V1 until the voltage thereacross is insuicient to maintain thyratron V1 conductive. The thyratron V1 then remains nonconductive until another trigger pulse is applied to grid 10b. In the meantime, the condenser C3 is recharged at a rate determined by the adjustment od tap 14 on selector control R2. A sawtooth wave form e2 is generated across condenser C2 at the rate of one sawtooth per input pulse e1 (FIG. l) and the sawtooth slope is determined by the setting of cylinder selector R2.

The sawtooth wave form e2 is applied to the grid 20h of the high MU triode V2 through the voltage divider R11-R12 from tap l5. The voltage divider R11- R12 biases tube V2 in such a `manner that tube V2 remains nonconducting until the sawtooth `has reached approximately two-thirds of its maximum value [near the point of maximum de/dt for a given time after initiationl The positive voltage [de/dt] on the grid 20h of tube V2, when t becomes conductive, together with the high MU of tube V2 cause the plate 20c of tube V2 to [rise to] fall from a value of approximately 250 volts [and to fall] to a minimum positive value of approximately 25 volts. At the time that this drop in the voltage of plate 20c of tube V2 takes place, the opposite terminals of condenser C4 are at substantially the sante voltage since one terminal is connected to resistance Rs and the other terminal to either resistance R3, R4 or R5. Since no appreciable current is flowing through either resistance R1 or the selected resistance R1. R4 or R5, while tube 20 is nonconductive, both terminals of condenser C4 are at a relatively high voltage close to that of the positive distributor bus 22 and condenser C4 is thus eectively discharged. Thus, when the plate voltage 20c of tube V2 drops from 250 volts to approximately 25 volts, upon tube 2() becoming suddenly conductive, this rapid decrease in voltage is transferred to the grid 23h of high MU tube 23, causing nonconduction of the latter'. Uniti this pulse is applied to grid 23h, tube V3 is fully conducting since the grid is held positive by any one of the selected resistances R3, R4 or R5 by means of selector switch .5'1 moving over

contacts

24, 25 or 26. The rapid decrease in voltage of plate 20c when transferred to grid 23h causes nonconduction of tube V1. At the same time, condenser C1 Charges through resistances R1, R4 or R5 and tube V2, again raising the potential of the right-hand terminal of condenser C4. When the voltage on tlze right-hand side of coudenser C1 has risen by a predetermined amount, tube V3 again becomes conductive.

When V3 ceases to conduct, the voltage at the anode 23C thereof rises abruptly. As soon as it conducts again, the voltage falls. The result is that a voltage having a wave form shown in FIG. l at e4 is produced at the anode 23C. The voltage e4 is supplied through voltage divider R13-R14 to the control grid 28h of thyratron V4. Thyratron V2 thus conducts only when both tube V3 is nonconducting as explained above and when a positive voltage is applied to the plate 28d of thyralron V4.

Referring to FIG. 2. the characteristic curves for the cycles of operation are shown. FIG. Z shows the relationships of these wave forms plotted with voltage as ordinates and time as abscissa. At a time t1 in the first part of curve [e3] e2, the time between to and t1 is deter'- mined by the setting of resistance R2. [This rapid decrease in voltage transferred to the grid 23h of high MU tube 23 causes nonconduction. Tube V3 is normally fully conducting since the grid is held slightly positive by any one of the selected resistances R3, R4 or R5 by means of selector switch S1 moving over

contacts

24, 25, or 26. Nonconduction continues until condenser C4 discharges through resistances R3, R4, or R5 to a point at which tube V3 again conducts at a time t2, as indicated in FIG. 2. The time between t1 and t2 is thus determined by the ratio Of R/C] Curve e3 in FIG. 2 shows the rapid decrease in voltage 0n the right-hand side of condenser C4 when tube 20 becomes conductive, this rapid decrease occurring at time t1. Curve e3 in FIG. 2 also shows the voltage rapidly rising again. At the time t2 in FIG. 2, the voltage depicted by curve e5 has risen to a value at which tube V3 again conducts. The time between t1 and t2 is thus determined by the RC of condenser C4 and re- 7 sistances R3, R4. or R5. [The voltage wave forms at the grid 23b ot tube V3 are indicated in FIG. 1 at e3, while the voltage wave forms at the plate 23e of tube 23 are indicated at e, in FIG. l. FIG. 2 shows the relationships of these wave forms plotted with voltages as ordinates and time as abscissa. The voltages e4 are supplied through voltage divider R13-R14 to the control grid 28h of thyratron V4. the voltage divider normally' biasing the thyratron to be nonconducting. Thyratron V4 thus conducts only when both tube V3 is nonconducting between times t1 and t2 indicated in FIG. 2, and when a positive voltage is applied to plate 28d. Application of a positive voltage to the plate 28d of thyratron V4 makes the thyratron conductive only at times between t1 and t2. The times are selectable by cylinder selector 14 and the ditl'erential tl-tg is selectable by switch Sy] The voltage wave form e4 ttltielt t'leterluiues tlte time tlze tltyratrt'ut V4 is conductive is also s/ton'n in FIG. 2. It will be apparent from tltis entre tltat tlte tlt'vrutron V4 is conductive between times t1 and t2, as long as a positive Voltage is applied to tlze anode 28d of tltyratrou V4. Tlze timing lietween points r1 and t2 is selectable by cylinder selector R2 and lty strife/t S1, cylinder selector R2 determining tlte slope of tlte voltage wave e? and .nvitelt S1 determining tlte slope of t/te rising portion of tlze voltage e3. The time ifi-r, can be .ret to correspond to tlte time between tite firing of tlte No. l plug and that at wlticlt any of ille other plugs would normally fire. By selecting tlte time tty-t1, any particular plug7 may be disabled b v causing tlte tlrvratron V1, to become conductive at tlte time tltat tlte points would open to cause firing of tltat particular plug.

[Referring particularly to the #l cylinder trigger, the thyratron V4 only conducts at times immediately after opening of points, and when the grid is not negative. Hence` when] Wlten t1-t0 is set to equal one engine cycle, i.e.` the time between successive #l cylinder rings, [since] normal trigger is present only on even cylinder firings, and not on odd tirings. As explained above, tltis is due to tlte inet tltat tlte s/tortiug of tlte No. l plugI one en /zitte cycle laler removes tite pulse wltielz would otlterwise be supplied by tlzat plug so that during tlte following eyt'le, tlrvratrou V4 would not jre. The conduction current of thyratron V4 on odd cylinder rings, however, also flows through the primary winding 29 of transformer T2, causing a trigger pluse to be generated inthe secondary winding 30 on these odd tirings. When the switch S4 is closed this self-generating trigger pulse can thus be used to fire tltyratron V1 during the even Cycles, as previously erplained, to cause thyratron V4 to conduct on both even and odd #l cylinder flrings.

The controls which have heretofore been described may be summarized as having the following functions: Rn-(Cylinder selector). Adjusts time delay between trigger pulse and thyratron conductionthus selecting cylindcr which is shunted.

S1(Number of cylinders selector). Permits selection of time period tzwtl during which thyratron V4 can conduct. For four-cylinder engines this, for example can be made twice as long as for an eight-cylinder engine, thus requiring no change of adjustment of R2 for greater change in r.p.m. of four-cylinder engines when a cylinder is effectively disabled as compared to [eight-cylinder disabled] the change in r.p.m. when a cylinder of un eight-cylinder engine is effectively disabled. This is due to the fact tltat when one Cylinder of a four-cylinder engine is etl'ectit-ely disabled, one-fourth of the cylinders are effeetirely disabled whereas in llte ease o l an eig/trerlindt'r engine, only one-eighth of Ille cylinders are efleetirely disabled.

SjHlPolarity selector). Permits operation with either polarity at breaker points.

Slt-Permits shunting of particular cylinder from which basic trigger is obtained.

Completely removes shunting action [or] of circuitry regardless of setting on all other controls.

The system of my invention may be embodied in many types of circuits and assemblies. For example, there may be provided a variety of forms of point shunting units, synchronizing units, in various applications as follows:

(A) Types of point shunting units (Kl Thyratrons:

Single to double (with and without transformer). Hott and cold cathode.

Vibrator driven points Coil driven points (B) Types ol synchronizing units t l ,l Time delay type:

(a) Thyratron-hot and cold cathode. tb) Hard tube. tcl (las tubeF-other than thyratron. (d) Electro mechanicalmthermal, i.e., agustin-blinkers.

(C) Areasofapplication (l l "Standard" combustion engines. (2) Fuel injection engines. (3) Diesel (shouting is non-electrical).

Referring to FIGS. 3a and 3b, there are shown two examples employing thc system and method of my in vention.

In FIG. 3a the system of my invention employs an adjustable time delay or counting system 48, connected with a thyratron or gas tube indicated at 49, which is coordinated in operation with the ignition circuit 4l. ln this figure the combustion engine is indicated generally at 40, including the ignition circuit broadly indicated at 4l, comprising alternately selective primary and secondary ele ments shunted to ground. In this arrangement, tlte counting system 48 causes the tltrratron to be conductive to disable the ignition circuit after a predetermined number of pulses.

In FlG. 3b there is shown an application of my invention to a system embodyingr the adjustable time delay circuits or counting system 48, but used in connection with a relay system or electro-mechanieally operated points. The relay system or the like is generally indicated at 50.

Referring to FIG. 4, which is a schematic view of the system in a six-cylinder engine, the relative position of engine crank shaft and the ignition events relative to time," "count, and phase angle, are shown for one complete engine cycle. Time, count, and phase angle at the start of the cycle are represented by the symbols t, n, and p, respectively. The symbols t1, n1, and p1 are time, number and phase angle at the rst ignition event. At any speed, nl is one (l). and p1 is 120 (crankshaft) for fom-myele engines. The value of t1 will depend upon engine speed at 100 r.p.m. 11:20 milliseconds). Integral multiples of the parameters shown can be used to sense electronically the disabling function for a selected cylinder or cylinders. The cylinder numbers 12() at the periphery identify their relative position in the engine and not their order of firing, which order is apparent from the clockwise arrangement on the schematic. For example, cylinder #6 is the fourth to lire in the engine cycle etc.

Both phase (p) and number or count (n) are not affected by engine speed whereas time (t) is inversely proportional to speed. lpso facto, devices employing phase and counting as selective means for disabling are independent of engine speed, time measurement devices, on the contrary, being sensitive to the speed of the engine.

While I have shown and described a preferred embodiment of my invention, it will be appreciated that other combinations of apparatus may be employed in carrying out the method of my invention, and I wish it to be understood that I do not confine `myself to the precise details of the arrangement set forth herein by way of illustration, as it is apparent that many changes and variations may be made therein, by those skilled in the art, without departing from the spirit of the invention or exceeding the scope of the appended claims.

What is claimed is:

1. In portable analyzing systems for multi-cylinder spark plug ignition internal combustion engines, a universally applicable method of testing relative performance of each cylinder of an operating engine including the steps of: applying a source of power to the analyzing system; electrically connecting the analyzing system to a common coil-distributor terminal, one spark plug cable and ground; deriving from the connection to said one spark plug cable a triggering pulse; setting cylinder disabling action time interval relative to the number of cylinders and the engine testing speed; thereafter running the engine at a predetermined xed throttle opening: selecting the absolute time interval between the firing of said one spark plug from which said triggering pulse is derived and the firing of the spark plug which is to be selectively disabled, then selectively disabling electronically one or more at a time, all cylinders of the engine; simultaneously measuring the change, if any, of one or more of the engine parameters as each one or more of said cylinders is disabled; and simultaneously identifying the measurement with said specic cylinder or cylinders so disabled.

2. The method according to claim l including the step of compensating for polarity of the ignition system following setting disabling action time control.

3. Portable apparatus for analyzing multi-cylinder internal combustion engines generating ignition pulses, comprising a source of electrical energy; conductive means connecting apparatus to a common coil-distributor terminal, any one spark plug circuit and ground, said apparatus including in connection: an electronic cylinder disabling circuit having a high impedance state and a low impedance state; a rst electronic timing circuit for predetermining the duration of the low impedance state; a second electronic timing circuit for determining the interval between the ring of said spark plug and the start of low impedance state of the cylinder disabling circuit, the time duration of which has been predetermined by the rst electronic timing circuit, said second electronic timing circuit being triggered from said conductive connection to a spark plug circuit, whereby the low impedance state of said cylinder disabling circuit selectively, by means of the second electronic timing circuit, disables one or more engine cylinders through the common coil-distributor, terminal connection and ground making possible a determination of the relative contribution of said one or more cylinders to overall engine performance.

4. Apparatus according to claim 3 further comprising means associated with said second timing circuit for cylinder identity.

5. Apparatus according to claim 3 further including cylinder identifying means common to said apparatus in the form of oscillographic presentation of engine ignition signal.

6. Apparatus according to claim 3 including torque indicating means in combination to determine relative contribution of said one or more cylinders.

7. Apparatus according to claim 3 including engine horsepower indicating means in combination to determine relative contribution of said one or more cylinders.

8. Apparatus according to claim 7 including manifold vacuum indicator means in combination to determine relative contribution of said one or more cylinders.

9. Apparatus according to claim 7 including engine speed measuring means in combination to determine relative contribution of said one or more [cyliders] cylinders.

10. Apparatus according to claim 3 including ignition system polarity compensating means.

11. Apparatus according to claim 10 including cylinder identifying means common to said apparatus in the form of oscillographic presentation of engine ignition signal.

12. Apparatus according to claim 10 including engine horsepower indicating means in combination to determine relative contribution of said one or more cylinders` 13. Apparatus according to claim 10 including engine speed measuring means in combination to determine relative contribution of said one or more cylinders.

14. Apparatus according to claim 10 in which manifold vacuum indicator means is combined to determine relative contribution of said one or more cylinders.

15. Apparatus according to claim 10 in which torque indicating means is combined to determine relative contribution of said one or more cylinders.

[16. Apparatus according to claim 14 including ignition system polarity compensating means] 17. Apparatus according to claim 4 in which the cylinder disabling circuit is a thyratron circuit.

[18. Apparatus according to claim 10 in which the cylinder `disabling circuit is a thyratron circuit] I9. The method according to claim l including the step of deriving from the disabling action a further pulse which is employed as a triggering pulse when said one spark plug7 is disabled.

20. Apparatus according to claim 3 further comprising means associated with .raid electronic cylinder disabling circuit for dcriving d triggering voltage which is applied to said apparatus to cause opt/ration of said cylinder disabling circuit when .raid one spark plug to which said conductive connection is made is disabled.

References Cited by the Examiner The following references, cited by the Examiner, are of record in the patented file of this patent or the original patent.

UNITED STATES PATENTS Re. 23,150 9/1949 Sexton 73-116 2,608,093 8/1952 Traver 73-116 2,652,727 9/1953 Richardson et al 73-398 2,809,344 10/1957 Mayer et al 37.4*19 2,842,956 7/1958 Uyehara et al 73-116 RICHARD C. QUEISSER, Primary Examiner. ROBERT EVANS, Examiner.

C. A. CUTTING, JERRY W. MYRACLE,

Assistant Examiners.