Analyzer for multi-cylinder internal combustion engine having means for identifying individual cylinders

Abstract

An analyzer for multicylinder internal combustion engines in which there is an electronic counter triggered by pulses from the ignition system and normally reset by the firing voltage applied to any of selected spark plugs in which the electronic counter has a plurality of stages corresponding to the number of cylinders in the engine and in which there is an electrical testing means adapted to be operated by the output signal of any one or more stages of the counter to produce an electrical effect for analyzing the performance of the engine.

Description

BRIEF SUMMARY OF THE INVENTION

In the analysis of the performance of multicylinder internal combustion engines, it is desirable to separately analyze the performance of each cylinder of the internal combustion engine. This can be done in several ways. It is desirable, for example, to selectively render each cylinder ineffective and to observe the effect on the over-all performance of rendering that cylinder ineffective. It is also desirable to individually indicate the voltage appearing across the igniter, commonly a spark plug. If the spark plug, for example, is shorted, then the voltage across the plug will be relatively low. If the spark plug gap is such that no firing takes place across the spark plug, then the voltage appearing across it will be high.

It is also important in analyzing the performance of an internal combustion engine to measure the "dwell" of the cam which operates the ignition points. The so-called "dwell" is a measure of time that the points are closed.

Various arrangements have been devised in the past for measuring each of the conditions discussed above. These arrangements have all had the drawback of either requiring certain special conditions such as, maintain the engine at constant speed or requiring an excessive number of connections. In some cases, the measurement of the conditions has been accomplished by the provision of a special generator attached to or driven by the main drive shaft.

An object of the present invention is to provide an engine analyzer for a multicylinder internal combustion engine in which very simple connections to the ignition system are required for individually analyzing the performance of the different cylinders of the engine and in which the apparatus is capable of individually identifying the particular cylinder in which the spark plug is being fired, regardless of the speed at which the engine is operated.

A further object of the present invention is to provide such an apparatus which is extremely compact and can be located at a point conveniently accessible to the mechanic testing the engine.

A further object of the invention is to provide an apparatus which can be employed to test any one of a number of conditions such as when one or more spark plugs are shorted, the voltage across any individual plug, the average voltage across the plugs, the average dwell time, or the dwell time for any individual cylinder.

A further object of the invention is to provide a signal identifying the particular cylinder in which the spark plug is being fired which signal is initiated at the time that the ignition points first close and continues until they reclose so that testing apparatus controlled thereby can be employed for accurately measuring conditions arising as soon as the points open.

A further object of the invention is to provide such an apparatus in which the spark plugs in any number of selected cylinders can be shorted at the same time.

A further object of the invention is to provide such an apparatus in which the spark plug of one cylinder is used as a reference and in which the apparatus continues to operate even when this reference spark plug is being shorted for test purposes.

A further object of the invention is to provide such an apparatus in which the apparatus provides an indication of the speed of the engine so that, for example, the effect of shorting the spark plug in any one or more cylinders can be readily observed.

Very broadly, I accomplish the objects of the invention by providing a counter which is pulsed each time that an ignition pulse is produced. The counter is reset by means of a connection to a selected igniter so that each time this igniter is energized, the counter starts over again. In its specific form, I employ an electronic ring counter in which each pulse applied to one of the input terminals causes the output of the counter to advance to another stage. By selectively connecting the outputs of one or more stages to control apparatus, it is possible to control the analyzer in accordance with whether any one or more cylinders are in the firing portion of their cycle. Where the igniter which controls the reset pulse is itself being shorted out, auxiliary means is effective to reset the counter at the end of each cycle of engine operation.

Further objects of the invention will be apparent from a consideration of the accompanying specification, claims and drawing.

BRIEF DESCRIPTION OF DRAWING

FIG. 1 is a schematic view of my engine analyzer;

FIG. 2 is a drawing of the front panel of the analyzer; and

FIG. 3 is a schematic view of the ring counter employed in my apparatus.

DETAILED DESCRIPTION

Referring to FIG. 1, I have shown the apparatus as connected to an automobile ignition system which is schematically shown in the drawing.

Referring first to the automobile ignition system, the numeral 10 indicates the usual ignition coil having a low voltage primary winding 11 and a high voltage secondary winding 12, the low voltage primary winding 11 being connected to the positive terminal of the automobile battery 13 through some switch such as an ignition switch 14. The opposite terminal of battery 13 is connected to ground at 15. The lower terminal of the primary winding 11 is connected to the switch blade 16 which cooperates with switch blade 17 to form the conventional breaker points. Switch blade 17 is grounded at 18. Cooperating with switch blade 16 is an eight-sided cam 19 which serves to separate switch blades 16 and 17 eight times for each revolution of cam 19. The numeral 20 indicates the conventional distributor having a distributor arm 21 which is driven by the engine along with the cam 19 and which sequentially makes contact with a plurality of terminals 22, each of which is connected to a different one of the igniters 24-31, which igniters normally take the form of the conventional spark plugs. The various igniters 24-31 are associated with respective cylinders, igniter 24 being associated with cylinder No. 1, for example. While I have shown the igniters or spark plugs as located in a continuous row, it is to be understood that they are associated with the cylinders in such a manner as to produce the desired firing sequence. The rotative arm 21 of the distributor 20 is connected in the conventional manner to the high tension side or upper terminal of coil 12 through a conductor 32. Upon rotation of the distributor 20, the voltage across coil 12 is successively applied to the various igniters or spark plugs in the desired firing sequence.

Turning now to the improved engine analyzer, this employs an electronic ring counter designated generally by the reference numeral 35. The ring counter is shown in detail in FIG. 3 and will be subsequently described in more detail. For the purposes of explaining the apparatus of FIG. 1, however, the ring counter will be merely described in general terms. It will be noted that this ring counter comprises eight stages which have been labeled with the numerals 1-8. Stage 1 is provided with a pair of input terminals 37 and 38 and a reset input terminal 39. Each of the stages 1-8 has an output terminal which has been designated in connection with the respective stages by the numerals 40-47, respectively. In addition, the stages 4, 6 and 8 are provided with auxiliary output terminals 50, 51 and 52, respectively. Each time that a pulse input signal is applied between terminals 37 and 38, the output signal advances from one of the stages to the next stage. Thus, assuming that an output signal appears on output terminal 40 of stage 1 and a pulse is applied between terminals 37 and 38, the output signal moves to terminal 41 of stage 2 and is removed from terminal 40 of stage 1. The next pulse is applied between terminals 37 and 38 and causes the output signal to be applied to terminal 42 of stage 3 and is removed from terminal 41 of stage 2. This operation continues until the output voltage appears, in the case of an eight cylinder engine, at terminal 47 of stage 8. Whenever a signal is applied to the reset terminal of stage 1, the entire counter is reset so that the output voltage again appears across terminal 40 of stage 1 so that the counter can again repeat its counting operation. As will be presently explained, input terminals 37 and 38 are connected across the distributor switch or "points" so that a pulse is applied each time a signal is applied to any of the plugs or igniters. The reset signal applied to terminal 39 is derived from the connection between the distributor and any selected plug so that whenever the selected plug is to be fired, the ring counter is reset. By always having the ring counter start its counting operation with the firing cycle of a particular plug, such as the plug for the "No. 1" cylinder, and by successively advancing the counter each time that the points open and close, it is possible to at all times know what cylinder is in the firing portion of its cycle, because the output of the counter will appear across a stage corresponding to the particular plug or igniter that is ready to be fired at that time. As will also be described in more detail, provision is made when the reference plug is being short-circuited for testing purposes to reset the ring counter whenever a complete cycle has been completed.

Referring now in more detail to the connections of the ring counter to the ignition system, it will be noted that the input terminals 37 and 38 of the ring counter are connected to the output terminals of a square wave generator 60, the input terminals of which are connected across the points 16 and 17 of the ignition system and across the conventional condenser in parallel with these points. The power check "Power Check" test. It will be seen that I have provided in a single compact piece of apparatus means for selectively performing any of various tests on the engine regardless of the speed at which the engine is operated and which tests can be performed either in connection with any one particular cylinder or in connection with the over-all average operation of the engine.

Claims

1. An analyzer for multicylinder internal combustion engines of the type having an electrical igniter for each cylinder, electrical ignition pulse generating means and a distributor for sequentially applying each generated ignition pulse to the igniter of a different cylinder in a predetermined sequence, said analyzer being usable with engines having different numbers of cylinders and comprising:

a first coupling circuit for producing discrete pulses at its output coincident with the application thereto of discrete input signals,

a first connector for coupling the input of said first coupling circuit to the electrical ignition pulse generator to receive signals at the frequency of generation of said ignition pulses,

a second coupling circuit producing discrete pulses at its output coincident to the application thereto of discrete input signals,

a second connector for coupling the input of the second coupling circuit to the igniter of an individual cylinder to receive signals at the frequency of firing of said cylinder,

a pulse counter having a plurality of stages corresponding to the maximum number of cylinders of any engine to be tested, each stage having an output connection, said counter having a first input connection and means operative upon successive pulses being applied to said input connection to cause an output signal to appear successively at the output connection of successive stages, said counter having a second intput connection, and means operative when a signal is applied to said second input connection to reset said counter to cause the output signal to appear at the output connection of the first stage regardless of whether an output signal has yet appeared at the output connections of all of said stages,

means for connecting said first input connection to the output of said first coupling circuit to cause said output signal to advance at the frequency of generation of said ignition pulses from one stage to the next stage,

means for connecting said second input connection to the output of said second coupling circuit so that the counter is reset each time that an ignition pulse would normally be applied to the igniter of the individual cylinder to which the input of said second coupling circuit is connected,

electrical testing means adapted to be controlled by the output signal of said counter and effective when a signal is applied thereto to produce an electrical effect useful in the analysis of the performance of the engine,

and switching means for selectively connecting said electrical testing means to the output connection of any one selected stage of said counter so that said testing means is operative to produce such an electrical effect concurrently with the period during which the generated pulse would normally be applied to the igniter of any selected cylinder.

2. The analyzer of claim 1 in which the electrical testing means is effective to indicate the voltage existing across any selected igniter.

3. The analyzer of claim 1 in which the electrical testing means may selectively indicate either the voltage across any selected igniter or the average voltage across all of the igniters.

4. The analyzer of claim 1 for use with an engine in which the electrical ignition pulse generating means comprises an ignition switch which is opened and closed for periods of time in connection with the generation of an ignition pulse and in which analyzer the electrical testing means is effective to indicate the "dwell" or the length of time the switch is closed.

5. The analyzer of claim 4 in which the electrical testing means may selectively indicate either the "dwell" in connection with the igniter of any one cylinder or the average "dwell" during a complete cycle of the engine.

6. The analyzer of claim 1 in which said switching means is adapted to connect said electrical testing means simultaneously to a plurality of selected output connections of said cylinder identifying means so that said electrical effect is produced whenever the ignition pulse would normally be applied to the igniters of certain selected cylinders.

7. The analyzer of claim 1 in which the electrical testing means is effective to render any selected igniter ineffective and in which the analyzer includes means for observing the effect on engine operation of said igniter being rendered ineffective.

8. The analyzer of claim 1 in which the means for observing the effect on engine operation of said igniter being rendered ineffective comprises an engine speed indicator controlled by the pulse generating means.

9. The analyzer of claim 1 in which said pulse counter is an electronic ring counter in which each successive pulse applied to said first input connection renders one stage nonconductive and the next succeeding stage conductive.

10. The analyzer of claim 1 in which the electrical testing means is effective to render any selected igniter ineffective and in which, when said igniter coupled to the input of said second coupling circuit is being rendered ineffective for testing purposes, auxiliary reset means are provided for applying a reset pulse to said second input connection independently of the connection of said second coupling circuit to said igniter.

11. The analyzer of claim 10 in which the auxiliary reset means comprises means connected to said counter and effective to apply said reset pulse when the counter indicates that the number of cylinders which have operated corresponds to the total number of cylinders in the engine.

12. The analyzer of claim 1 for use with an engine in which the electrical ignition pulse generating means comprises an ignition switch which is closed and opened for periods of time in connection with the generation of an ignition pulse which is initiated upon the opening of said switch and in which the output signal successively applied to each output connection of said cylinder identifying means pulse counter is initiated at the time that said switch is first closed and continuous until after said switch opens.

13. The analyzer of claim 12 in which the output signal successively applied to each output connection of said cylinder identifying means pulse counter begins when said switch is first closed and continues until said switch recloses after being opened.

14. A compression and ignition test circuit for an automotive type engine; said engine including a plurality of cylinders and an ignition circuit connected to said cylinders including an igniter for each cylinder and a pair of distributor points, said compression and ignition test circuit including high speed switching means operable between an open and closed circuit condition, means for operatively connecting said switching means across the distributor points to cause the points to be short-circuited each time that said switching means is closed, operating means connected to said high speed switching means and energizable to cause said high speed switching means to assume a closed circuit condition for a predetermined interval less than the time interval between subsequent closings of said distributor points; energizing means having input and output terminals, means for operatively connecting the input terminals of said energizing means to the distributor points, said energizing means having its output terminals connected to said operating means and effective to cyclically energize said operating means in synchronism with a preselected number of operations of said distributor points whereby said energizing means eenergizes said operating means after a predetermined number of operations of said distributor points thereby to close said high speed switching means to short-circuit said distributor points in a predetermined repetitive pattern to continually disable the operation of at least one cylinder of said engine; means connected to said energizing means and responsive to the energization of one of said igniters for initiating each cycle of said energizing means so that the time of energization of said operating means is related to the time of firing of the igniter of a predetermined selected cylinder; and a cylinder selection switching means connected between said energizing means and said operating means for varying said predetermined repetitive pattern for the selection of a different selected cylinder for disabling other than said at least one selected cylinder.

15. The device as set forth in claim 14 wherein said cylinder selection switching means includes cylinder selecting switches for at least one-half of the cylinders in said engine.

16. A compression and ignition test circuit for an automotive type engine; said engine including a plurality of cylinders and an ignition circuit connected to said cylinders including an igniter for each cylinder and a pair of distributor points; said test circuit including: a controlled rectifier having an anode and cathode terminals connected across said distributor points and a gate terminal; a pulse generator having input terminals connected to said distributor points and an output circuit connected to said gate terminal of said controlled rectifier; said pulse generator cyclically generating one output pulse in synchronism with a predetermined number of opening operations of said distributor points; means connected to said pulse generator and responsive to the energization of one of said igniters for initiating each cycle of said pulse generator so that the timing of said output pulse is related to the time of firing of the igniter of a predetermined selected cylinder; and pulse advancing means for shifting the point in the pattern of distributor point operation at which said one output pulse is generated and hence the particular cylinder whose timing of firing is being sensed.

17. The device as set forth in claim 16 wherein said pulse generator comprises a ring counter having a pair of input terminals and a plurality of output terminals, there being at least one output terminal for each of said igniters; said pair of input terminals being connected across said distributor points; said pulse advancing means comprising switching means for selectively connecting one of said output terminals to said gate terminal of said controlled rectifier.

18. The device as set forth in claim 16 wherein said pulse generator comprises a ring counter having a pair of input terminals and a plurality of output terminals, there being at least one output terminal for each of said igniters; means connected across the distributor points and connected to said pair of input terminals for applying to said input terminals at the time that the distributor points first open a pulse which causes said ring counter to shift the portion of the cycle at which said output pulse occurs; and said pulse advancing means comprising switching means for selectively connecting one of said output terminals to said gate terminal of said controlled rectifier.

19. In an apparatus for analyzing the operation of a multiple cylinder internal combustion engine having an ignition time interval for each cylinder during which ignition normally occurs, the combination which comprises:

means coupled to the engine for generating a first control pulse in response to the ignition time interval for each of the cylinders,

means responsive to each occurrence of the first control pulse for providing a second control pulse which occurs at a time following the initiation of the first control pulse by a time period which is directly proportional to the interval between the successive times of cylinder ignition,

means responsive to each occurrence of the second control pulse for generating anticipatory ignition suppression signals in advance of the ignition times in respective cylinders, and

means coupled to the engine and responsive to the ignition suppression signals for suppressing the ignition in a selected cylinder.

20. The combination as defined in claim 19 wherein the means for generating the ignition suppression signals includes:

a multistage ring counter having a stage individually associated with each cylinder,

means coupled to the engine and responsive to the ignition of the first cylinder thereof for resetting the stages of the ring counter, and

means for advancing the count in the ring counter in response to the occurrence of each second control pulse.

21. The combination as defined in claim 19 including means coupled to the number one cylinder of the engine and to the suppression signal generating means for generating a third control pulse which corresponds to the firing time of the first cylinder.

22. The combination as defined in claim 19 including means responsive to the first control pulse for providing an indication of engine r.p.m., whereby the power contribution of individual cylinders can be ascertained when the ignition in each of the cylinders is suppressed.

23. Apparatus for analyzing the functioning of a multiple-cylinder internal combustion engine having an ignition coil, comprising:

means for picking up ignition pulses from said ignition coil;

pulse shaping means connected to said ignition pulse pickup means for producing a first control pulse therefrom upon each occurrence of an ignition pulse;

means responsive to each first control pulse for providing a second control pulse which occurs at a time following the initiation of the first control pulse by a time period which is directly proportional to the interval between successive ones of the ignition pulses;

means connected to the first cylinder of said multiple-cylinder engine for producing a third control pulse whenever the first cylinder fires;

a multi-stage ring pulse counter having stages equal in number to the number of cylinders in said engine;

reset means responsive to the third control pulse to place all of the stages of the pulse counter in a reset condition;

means for incrementally advancing the counter in the ring pulse counter with the occurrence of each of the second control pulses; and

utilization means connected to the output of the stages of the ring pulse counter and responsive to the pulse count therein.

24. In a system for diagnosing an engine including a source of periodic cycles of ignition signals, improved apparatus for preventing one or more predetermined ignition signals in each cycle from energizing engine components which are normally energized by said predetermined ignition signals comprising in combination:

input means for receiving said periodic cycles of ignition signals from said source;

generating means for generating a clock pulse in response to the receipt of each ignition signal by the input means, said generating means comprising clock means for producing in response to each ignition signal a clock pulse having a predetermined amplitude and having a duration proportional to the duration of the ignition signal;

counting means for producing counting states representative of the number of pulses received from said generating means;

adjustable resetting means for resetting the counting means to a predetermined counting state after the counting means has counted through a predetermined number of counting states;

removable setting means for setting the counting means to an initial counting state in response to the operation of a predetermined one of the engine components by an ignition signal;

adjustable selecting means for producing a disabling pulse in response to a predetermined counting state of the counting means; and

disabling means responsive to the disabling pulse for preventing any simultaneously-occurring ignition signal from energizing the engine component normally energized by the simultaneously-occurring ignition

signal.

25. In a system for diagnosing an engine including a source of periodic cycles of ignition signals, improved apparatus for preventing one or more predetermined ignition signals in each cycle from energizing engine components which are normally energized by said predetermined ignition signals comprising in combination:

input means for receiving said periodic cycles of ignition signals from said source;

generating means operatively connected to the input means for generating a clock pulse in response to the receipt of each ignition signal by the input means;

counting means operatively connected to the generating means for producing counting states representative of the number of pulses received from said generating means, said counting means comprising first, second and third binary flip-flop circuits each having an input circuit and an output circuit and each capable of producing a single output pulse for each two pulses transmitted to its input circuit;

adjustable resetting means operatively connected to the counting means for resetting the counting means to a predetermined counting state after the counting means has counted through a predetermined number of counting states;

removable setting means operatively connected to the counting means for setting the counting means to an initial counting state in response to the operation of a predetermined one of the engine components by an ignition signal;

disabling means operatively connected to the selecting means and responsive to the disabling pulse for preventing any simultaneously-occurring ignition signal from energizing the engine component normally energized by the simultaneously-occurring ignition signal.