U.S. patent number 3,696,303 [Application Number 05/025,002] was granted by the patent office on 1972-10-03 for process and apparatus for producing trigger pulses.
Invention is credited to Gunter Hartig.
United States Patent |
3,696,303 |
Hartig |
October 3, 1972 |
PROCESS AND APPARATUS FOR PRODUCING TRIGGER PULSES
Abstract
Apparatus for producing a trigger pulse at a preselected point
which is off-set from a reference point in the movement of a
cyclically moving mechanical device which includes a pulse
generator adapted to be connected to the device which produces a
series of pulses during each cycle of the device. A counter counts
the pulses. A gate connects the pulse generator with the counter
and control means enables the gate for a time period corresponding
to the interval of time between movement of the mechanical device
between the preselected and reference points. Trigger means is
provided which increments the count in the counter to produce a
trigger pulse after a desired count has been reached. A novel
method of producing the trigger is also disclosed.
Inventors: |
Hartig; Gunter (7500 Karlsruhe,
DT) |
Family
ID: |
5730350 |
Appl.
No.: |
05/025,002 |
Filed: |
April 2, 1970 |
Foreign Application Priority Data
|
|
|
|
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Apr 3, 1969 [DT] |
|
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P 19 17 389.8 |
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Current U.S.
Class: |
327/286; 377/15;
377/44; 377/27 |
Current CPC
Class: |
F02P
7/061 (20130101); F02P 7/0675 (20130101); F02P
7/0775 (20130101); F02P 5/15 (20130101); Y02T
10/46 (20130101); Y02T 10/40 (20130101) |
Current International
Class: |
F02P
7/077 (20060101); F02P 7/00 (20060101); F02P
5/15 (20060101); F02P 7/06 (20060101); F02P
7/067 (20060101); H03k 003/00 () |
Field of
Search: |
;328/55,63,72,73,74,140,141 ;340/268T ;307/215,247,273 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Heyman; John S.
Claims
I claim:
1. A method for producing a trigger pulse at a preselected point
which is off-set from a reference point in the movement of a
cyclically moving mechanical device comprising:
a. producing a series of pulses during each cycle of movement of
the device wherein corresponding pulses in successive series are
produced at the same point in the movement of the device,
b. counting a predetermined number of the pulses in at least a
first series in which said predetermined number corresponds to the
difference in time between said preselected and reference
points,
c. incrementing said count by respective succeeding pulses until a
desired count is reached,
d. and producing said trigger pulse when the next succeeding pulse
after said desired count is produced;
e. said method comprising the further steps of setting to zero
prior to initiating a count therein a first, second and third
counter; counting said predetermined number of pulses in said first
series in a first counter; counting said predetermined number of
pulses in a second series in said second counter; counting all of
the pulses in a series in said third counter; and alternately
incrementing said first and second counters with said third counter
to produce said trigger pulse.
2. The method of claim 1, in which said count is incremented by a
number of pulses equal to said predetermined number to reach said
desired count.
3. The method of claim 1, in which said first pulse series is an
odd pulse series, and said incrementing comprises counting pulses
in a second pulse series wherein said second pulse series is an
even pulse series.
4. Apparatus for producing a trigger pulse at a preselected point
which is off-set from a reference point in the movement of a
cyclically moving mechanical device comprising:
a. a pulse generator adapted to be connected to said device for
producing a series of pulses during each cycle related to said
movement wherein corresponding pulses in successive series are
produced at the same point in the movement of the device,
b. at least a first counter for counting said pulses,
c. gate means connecting said pulse generator with said first
counter for passing said pulses to said first counter in response
to a control signal,
d. control signal means connected to said gate means for producing
a control signal for a predetermined interval of time corresponding
to the time for movement of said mechanical device between said
preselected and reference points,
e. and trigger means for incrementing the pulses counted by said
first counter to produce a trigger pulse after a desired count has
been reached,
f. said trigger means including means for applying an additional
control signal to said gate means after said predetermined interval
of time to permit succeeding pulses to be counted by said counter
until said desired count is reached.
5. Apparatus for producing a trigger pulse at a preselected point
which is off-set from a reference point in the movement of a
cyclically moving mechanical device comprising:
a. a pulse generator adapted to be connected to said device for
producing a series of pulses during each cycle related to said
movement wherein corresponding pulses in successive series are
produced at the same point in the movement of the device,
b. at least a first counter for counting said pulses,
c. gate means connecting said pulse generator with said first
counter for passing said pulses to said first counter in response
to a control signal,
d. control signal means connected to said gate means for producing
a control signal for a predetermined interval of time corresponding
to the time for movement of said mechanical device between said
preselected and reference points,
e. and trigger means for incrementing the pulses counted by said
first counter to produce a trigger pulse after a desired count has
been reached,
f. a second counter,
g. said gate means interconnecting said first, and second counters
and said pulse generator for applying said series of pulses to said
first and second counters alternately whereby said first and second
counters count pulses when said control signal is present,
h. a third counter connected to said pulse generator for counting
the pulses produced thereby,
i. and adding means connected to said first, second and third
counters for alternately adding the contents of said second and
first counter with said third counter to produce said trigger pulse
after said desired count is reached.
6. Apparatus as in claim 5, in which said gate means includes
switch means responsive to a switch signal for alternately
switching the output of said pulse generator from said first
counter to said second counter, and a switch signal generator for
producing said switch signal when the time interval between pulses
exceeds a preselected value.
7. Apparatus as in claim 6, in which said first, second and third
counters are adapted to be set to zero when a signal is applied to
an erase terminal, and lead means for connecting said switch signal
generator with said erase terminals for setting said counters to
zero.
8. Apparatus as in claim 5, in which said control signal means
includes pulse lengthing means for maintaining a control signal for
a sufficient interval of time so said gate means passes full width
pulses.
9. Apparatus as in claim 6, in which said control signal means
includes means responsive to said switch signal for initiating said
control signal in response to said switch signal.
10. Apparatus as in claim 6, and disabling means connected to said
trigger means and said switch signal generator for disabling said
switch signal generator when said switch and trigger pulses fail to
alternate.
11. Apparatus as in claim 6, and detection means for detecting the
number of pulses in said first or second counter in a predetermined
time interval and for delaying the operation of said switch signal
generator if the number of pulses in said first and second counters
is below a preselected amount.
12. Apparatus as in claim 4, in which said pulse generator includes
a main pulse generator for generating said series of pulses and an
auxiliary pulse generator for generating at least an auxiliary
pulse for each cycle of operation of said mechanical device, lead
means for connecting said auxiliary pulse generator to said control
signal means to produce said control signal, said trigger means
including means for connecting said main pulse generator to said
first counter after said control signal has been removed, whereby
said first counter counts additional pulses in said series.
13. Apparatus as in claim 12, in which said first counter has a
clear terminal whereby said counter is set to zero when a signal is
applied to said clear terminal, and lead means connecting said
auxiliary pulse generator with said clear terminal to set said
counter to zero.
14. Apparatus as in claim 12, in which said control signal
generator comprises a monostable multivibrator.
Description
The invention relates to a method and an apparatus for producing a
trigger pulse which is synchronous with an event in a periodical
motion of variable period length but displaced therefrom by a
predetermined length of time that is independent of the period
length.
Such trigger pulses are needed, for example, as ignition pulses in
internal combustion engines, in which the length of the cycle of
the piston movement continually changes and in which an ignition
pulse has to be delivered before the piston reaches the top dead
center. Methods and apparatus are already known whereby
corresponding ignition pulses can be produced, examples being an
apparatus having a centrifugal weight and switch contact, and an
apparatus using a vacuum box.
These known apparatus, however, have the disadvantage that, due to
their mechanical method of operation and the free play of the parts
in relation to one another which this entails, and which is
aggravated by mechanical wear, they are relatively inaccurate and
become increasingly inaccurate with the passage of time due to
fouling. Furthermore, these apparatus are relatively unreliable and
are difficult to adapt to various states of operation of the
internal combustion engine, such as starting and running, and
operation with acceleration of the rotatory speed, or the like.
It is the object of the invention to devise a process of the kind
first mentioned, and an apparatus for its performance, while
avoiding the above-mentioned disadvantages. In particular, great
accuracy and repeatability are to be achieved and to be maintained
without variation during the life of the apparatus of the
invention.
This object is accomplished according to the invention in that,
during successive cycles of motion, series of pulses are produced,
each of which is associated with one cycle of movement and is
synchronized with respect thereto; that the pulses belonging to a
first of these pulse series (reference series) and produced during
a predetermined time s that is shorter than the total duration of
the individual pulse series are counted or stored (reference
counting or reference storing) beginning with the first pulse of
the series; that the pulses of a second series of pulses coming at
a later time--preferably the next series of pulses--(trigger
series) are counted or stored, beginning with the first impulse of
the series, at least until the sum of counted or stored pulses of
the first and second series is equal to a certain number N, and is
preferably equal to the given number of all pulses of one of the
series plus 1 (trigger counting or trigger storing), and that when
this counting or storage state is reached, a trigger pulse is
produced.
During each period of motion, at least one reference and one
trigger series can be produced successively and subjected to a
reference and trigger counting or storage for the production of at
least one trigger pulse.
The time interval between predetermined successive pulses of the
reference series can be a first function (f.sub.1) of the velocity
and/or the phase of the motion, while the time interval between
predetermined pulses of the trigger series can be a second function
(f.sub.2) of the velocity and/or the phase of the motion.
In particular, it is possible that the pulses of the reference
series follow one another at uniform time intervals, while the
pulses of the trigger series follow one another in pregressively
increasing or diminishing time intervals. In a particularly simple
embodiment of the process of the invention, which is advantageous
in some applications on account of its simplicity, the pulses of
each series succeed one another at uniform time intervals whose
absolute magnitude depends in each case on the velocity of the
motion.
Although the number of pulses in the reference and trigger series
will generally be different, it may be especially advantageous for
the reference series to consist of the same number of pulses as the
trigger series. In this case it is often sufficient for a single
pulse series to be produced during each cycle of the motion.
In a preferred embodiment of the process of the invention, it is
possible for every (2n-1th pulse series to be subjected to a
reference count or storage and every (2nth pulse series to be
subjected to a trigger count or storage, n being a whole number
equal to or greater than 1. In many cases it is sufficient to use a
single counter or storage and first feed it with the pulses of the
(2n-1th pulse series for a predetermined time s and then feed it
with the (2nth pulse series at least until the sum of the counted
or stored pulses is equal to N or to an integral multiple of N.
It is especially advantageous for each series of a plurality of
successive series of pulses to be subjected both to a reference
counting or storage and to a trigger counting or storage,
especially in such a manner that each series of pulses is used as a
reference series during the one cycle of motion and as a trigger
series during the next cycle of motion. In further development of
the process of the invention, this can be brought about by
registering the pulse series alternately by means of three counters
or storages by registering in a first counter or storage only the
first pulses of every (2n-1th series which appear during the
predetermined time period s, n being a whole number equal to or
greater than 1, and registering in a second counter or storage only
the first pulses of every (2nth series which appear during the
predetermined time period s, the first or second counter or
storage, as the case may be, being cleared or reset before the
commencement of the next count or storage, as the case may be,
while all pulses of every series are registered in a third counter
or storage and a resetting of the counter or a clearing of the
storage being performed prior to the beginning of the next series
of pulses, and the first and second storage in the cycle of motion
that comes between two counting or storage processes in the
particular storage serving as the reference counter or storage, as
the case may be, whose reading or content is compared with that of
the third counter or storage in order to produce the triggering
pulse.
A substantial simplification is achieved if, in addition to the
pulses of the reference and trigger series, one or more auxiliary
pulses are produced which occur simultaneously with the pulses of
the reference and/or trigger series and/or are phase-shifted in
relation to the latter, and are used to control the reference
and/or trigger count or storage. Of course, pulses of the reference
and/or trigger series can also be used for controlling purposes,
i.e., they can serve simultaneously as auxiliary pulses.
An especially compact and inexpensive circuitry can be obtained in
the performance of the process of the invention if a plurality of
auxiliary pulses are produced for each reference and trigger
series.
Preferentially, one auxiliary pulse for each reference and trigger
series serves to clear (restore to zero) the counter or counters or
storages prior to the counting or storing process. Furthermore, one
auxiliary pulse per reference and trigger series can serve to
trigger a pulse of the length s, which is also used in the
controlling of the counting or storing process; in this case the
functions of the previously mentioned two auxiliary pulses can be
performed by a single auxiliary pulse.
Other auxiliary pulses can serve to control logical circuit
elements by which the counting or storing processes are
controlled.
It has furthermore been found that the general principle of the
invention, in the process for the production of trigger pulses
which precede by a certain time interval a certain phase situation
(triggering phase) in a movement that takes place in constantly
variable periodicity, while during the said time interval series of
pulses synchronously associated with successive cycles of motion
are produced during the said cycles, consists in the fact that, by
means of a first series of pulses (reference series) the phase
shift .phi. corresponding to the predetermined time period s is
determined and is subtracted by means of a second series of pulses
(trigger series) from an arbitrary phase situation .phi..sub.1
which is advanced by more than .phi. with reference to the
triggering phase .phi..sub.0 so that the trigger pulse is produced
after the passage of the phase difference .phi..sub.1 -.phi.
computed from .phi..sub.1.
Preferentially, with the aid of additional pulses additional
adjustment angles can be subtracted from the advanced phase
situation .phi..sub.1 or added thereto.
An apparatus for the performance of the process of the invention,
which can also be viewed as a miniature computer, is characterized
according to the invention by a pulse generator coupled to the
motion that is involved in order to produce series of pulses that
are synchronous with reference to the motion; by a logic circuit
device coupled to the pulse generator and having at least one gate
in the path of conduction of the pulses of the reference series; by
a device opening the gate during a predetermined time period s; by
at least one counter or storage following the logic circuit device,
and by a pulse generator coupled to or combined with the counter or
storage for the production of the trigger pulse.
In one possible embodiment, the apparatus according to the
invention has a gate which opens alternately, as the pulse series
alternate, (a) only for the predetermined time period s after the
beginning of a reference series, and then (b) through the entire
duration of a series of pulses, and which is disposed in the
conduction path both of the reference series and of the trigger
series and cooperates preferably with a single counter or
storage.
A preferred embodiment of the apparatus of the invention is
characterized by a first and second counter or storage, each
connected by a switching means to the output of the gate in such a
manner that the pulses passing through the gate are alternately
registered by the first or second counter or storage as the pulse
series alternate, and a third counter or storage constantly coupled
to the pulse generator, and an adding device connected to the
outputs of all three storages, which has two adding units, one of
which processes the values registered by the first and third
counter or storage and the other processes the values registered by
the second and third counter or storage and, when the predetermined
value has been registered, produces a triggering pulse.
If auxiliary pulses, or at least one auxiliary pulse is used, the
apparatus for the performance of the process of the invention can
be constructed at an especially low investment in circuitry. Such
an apparatus is characterized by a main pulse generator in which
the pulses of the reference and trigger sequence are produced, and
an auxiliary pulse generator in which at least one auxiliary pulse
is produced, the main pulse generator being connected through at
least a first logical circuit element to the input of the counter
or storage which performs the reference or trigger pulse counting
or storage (main counter or storage), and the main or auxiliary
pulse generator being coupled to the input of a pulse generator for
the production of a pulse of the length or duration s, and the
outputs of the latter pulse generator and of the main and auxiliary
pulse generators being connected through logical circuits alone or
through logical circuits in conjunction with additional circuit
elements in such a manner that a reference and trigger count or
storage is performed in the main counter or storage and the main
counter or storage is cleared before or after.
In this apparatus, inverted AND gates and/or inverted OR gates can
be used preferentially as logical circuit elements. A monostable
multivibrator, for example, is suitable as a pulse generator to
produce the pulse of the length or duration s.
The invention will be further explained below with the aid of a
number of especially preferred embodiments represented in FIGS. 1
to 9 of the drawing, and additional advantages and features will be
discussed, but it is not restricted to these and can be applied
successfully under the principles that are set forth, without
departing from the scope of the invention and the general idea
underlying same.
FIG. 1 shows a pulse generator for the production of periodically
recurrent series of pulses.
FIG. 2 shows a block diagram of a first embodiment of the apparatus
of the invention.
FIGS. 3 and 4 show a detailed circuit diagram of the apparatus
represented in FIG. 2.
FIG. 5 is a circuit diagram of a second embodiment of the
invention.
FIG. 6 is a representation of the pulse series that are produced in
the transducers of the apparatus of FIG. 5 in the time period
t.
FIG. 7 is a circuit diagram of a third embodiment of the apparatus
of the invention.
FIG. 8 is a circuit diagram of a fourth embodiment of the apparatus
of the invention, and
FIG. 9 is the representation of pulse series which are produced in
the apparatus of FIG. 8.
The pulse generator represented in FIG. 1 consists of a disk 1,
equipped with teeth 2 over a portion of the periphery, which is
coupled to the motion that is involved--to the crankshaft of an
internal combustion engine, for example. In the present example,
the teeth 2 are equidistantly arranged, although they can be
provided in a different arrangement in which there will be no
uniformity between the reference magnitude S and the time between
the triggering pulse and the point of reference. When the teeth 2
pass by the pickup 3, pulses 4 are produced, a series of pulses
being generated during each rotation of the disk, and the number of
pulses per series depending on the number of teeth 2. Furthermore,
an apparatus 5 is provided, at whose output S a magnitude S
resulting from, say, the temperature or some other factor in the
operating state of, for example, an internal combustion engine.
This magnitude S can be used for the purpose of varying the
predetermined time period s by which the trigger pulse is to be
displaced from the top dead center in the internal combustion
engine. By taking S or s, as the case may be, as a function of the
rotatory speed, any desired control characteristic can be achieved,
this characteristic being a curve representing the relationship
between the angular velocity W and the time between the trigger
point and the point of reference.
The circuit represented in FIG. 2 comprises a pulse former 11 in
which non-rectangular pulses of the pulse generator of FIG. 1 are
transformed to rectangular shape. If the time interval between two
pulse edge is greater than a given time t, the canceling pulse
generator 12 produces a canceling pulse. This canceling pulse comes
at precisely the end of the time interval t following the end of
the pulse series involved, and lies in the dead period between this
preceding pulse series and the following pulse series. The
canceling pulses serve the purpose, among other purposes, of
clearing at the end of each pulse series the storage 28 which is
continuously counting the pulses of each pulse series. At the same
time, the canceling pulse forms the start information for the gate
circuit 17 which, beginning from the first pulse edge of a series,
supplies a pulse of the length s. This pulse is lengthened in the
pulse lengthener 18 by the length of the pulse of the series still
being picked up at the end of s, so that the gate 19 admits only
full-length pulses from the pulse former 11. This is important
because if the gate 19 is operated on the edge of a pulse
additional unwanted pulses might be produced. The pulses of the
series which pas through the gate 19, i.e., the pulses from the
first pulse of the series through to the end of the period s, are
alternately fed through the switches 20 to storages 16 and 21 where
they are stored. The alternative switching is brought about by the
one-half divider 14 which, in the present embodiment, reverses the
counting and canceling inputs of storages 16 and 21, 2 microseconds
after each canceling pulse. The duration of the canceling pulse
amounts, for example, to one microsecond, so that the reversal does
not take place until the canceling process has completely ended.
If, for example, storage 16 has been canceled, or cleared, a
portion of the still arriving pulse series is stored through the
gate 19. Before the beginning of the next pulse series the storage
21 is cleared, so that a portion of the latter pulse series then
passes into storage 21. Consequently, storage 16, for example, is
used as the reference storage in each odd-numbered series of pulses
and storage 21 as the reference storage in each even-numbered
series of pulses, i.e., serves to store the first pulse of these
series which occurs during the interval s. To each of the outputs
of storages 16 and 21 there is connected one adding matrix 25 and
27, respectively. The addition matrix 25 compares the value
recorded by storage 16 with the value recorded by storage 28 and
yields a pulse when the sum of the readings of the two storages
comes to a predetermined value--15, for example. In like manner, a
comparison is made in addition matrix 27 of the readings of
storages 21 and 28, and when the predetermined total of the two
storages is reached--a total of 15 stored pulses for example--the
addition matrix 27 likewise produces a pulse at the output. The
addition matrixes 25 and 27 are alternately reversed by a switching
device 24: whenever pulses are stored in the storage 16 during one
switching interval, a comparison of storages 21 and 28 is made,
while in the next switching interval a comparison of storages 16
and 28 is performed. The pulse obtained at the output of the
switching device 24 is the desired trigger pulse.
In addition to the systems mentioned above, other logic circuits
are provided in the embodiment according to FIGS. 2 to 4 in order
to meet additional requirements. During the starting period of a
movement process--for example during the starting of an internal
combustion engine--the period between successive pulses of the
series is longer than the above-mentioned time period t. The result
would be that, within the series of pulses a cancel pulse would
follow every individual pulse, so that the required predetermined
total--15, for example--which is needed in order to produce the
trigger pulse, would never be reached. To prevent this, the time t
is lengthened 12-fold, for example, to t' whenever it is found
through matrix 23 that the storage 16 and/or storage 21 have so far
stored only one pulse. This is the case in the event of very slow
rotations, namely when only the initial pulse of the series falls
within the time period s.
Another additional logic circuit 26 is advantageous for the
following reason. Owing to a disturbance it may come about that the
longer time t' is operative whereas due to the frequency of the
pulse succession the shorter time period t would be necessary. In
this state of operation, no cancel pulse would be produced, and the
storage, in the state corresponding to the occurrence of only an
initial pulse, would always continue in this state, since it sets
the time t' instead of t. To prevent this erroneous manner of
operation the logic circuit 26 has been provided. This circuit
produces an additional cancel pulse if the trigger pulse and the
cancel pulse do not occur alternately, which is always the case if
the correct state of operation.
Lastly, the additional logic circuit 22 serves to facilitate the
correction of the apparatus according to the invention. It permits
the apparatus to be supervised in operation and supplies output
information from the instant in which the trigger pulse enters
time-wise into the s interval, which commences precisely in the
middle of the control interval.
The length of the time interval s can be set externally through the
S input and thus the control characteristic can be varied.
In the detailed circuit diagrams represented in FIGS. 3 and 4 for
the logic system of FIG. 2, conventional cirduit symbols are used
so as to enable the technical man to understand easily the manner
of operation of the circuits shown in FIGS. 3 and 4 as described
above with reference to FIG. 2.
For example, this circuit can be built of the elements listed as
follows:
Components 31 and 37 T AA 293 Component 32 1/2 SN 7474 N "33 1/4 SN
7400 N "34 T AA 293 plus 4 .times. S X 3708 "35 1/2 SN 7473 N "36
1/2 SN 7450 N "38 Pilot lamp 6V/40 mA "39 1/2 SN 7460 N "40 1/2 SN
7420 N "41 Condensers 100 nF/30V
The designations of these components correspond to the model
numbers of Texas Instruments, USA (integrated circuits of series SN
74) and of Valvo of Germany (especially TAA 293) (see also the
company's publication "Technische Informationen Valvo," No. 127,
October 1968, on the applications of the TAA 293 ("Anwendung des
TAA 293")).
In FIG. 5, 50 represents a wheel that is coupled with the process
of movement of an engine piston, e.g., through the crankshaft of a
motor vehicle, and that is provided with projections 51a-51c on its
circumference, the said projections being carried past the
transducers 54 or 55 as the case may be, when wheel 50 rotates
about axis 53 in the direction of the arrow. When such a projection
51a, b or c moves past one of the transducers, a pulse is produced
in transducer 54 and/or 55. In transducer 54 there is produced the
pulse series I represented in FIG. 6, and in transducer 55 there is
produced the pulse series II.
Pulse series II commences ahead of pulse series I with a pulse A
which develops when the projection 51a runs past the transducer 55,
while at the same time no pulse is produced in transducer 54. The
result is that, due to the intereaction of the two inverted AND
gates 56 and 57 a restore pulse appears in line 58a and restores
the storage 59 to zero. The counter or storage 59 is so constructed
that a positive pulse appears in the output line 58b during the
period in which the counter or storage 59 is at zero.
After storage 59 has thus been cleared, the movement of projection
51b past transducer 54 produces a pulse in the latter which through
the inverted AND gate 60 triggers a monostable multivibrator 61
which is so designed that a pulse of the duration s is produced at
its output, beginning from the moment in which it is triggered.
Since the output 62 of the monostable multivibrator 61 is connected
by line 63 to transducer 55, a positive pulse is produced at
transducer 55 during the period s although at first no further
projections are passing transducer 55 after projection 51a has
passed it. This state is represented by the pulse B that is
represented in broken lines. During the time period s the pulses of
the pulse series I produced in the transducer 54 are fed, beginning
with pulse C, to the storage 59 through the inverted AND gate 64,
and are counted and stored there. In the example shown, these are
the six pulses from C to D of the total of 18 pulses of pulse
series I. After the time s, i.e., after the pulse D has appeared,
no further pulses are recorded in storage 59 for a while, because
after the end of the period s the inverted AND gate admits no
pulses up to and including pulse E. But as soon as pulses occur
simultaneously in transducers 54 and 55, i.e., beginning with the
appearance of pulses F and K, the inverted AND gate 64 is "open"
again, and storage 59 then stores the pulses of series F-G, doing
so until a predetermined storage state is reached. When this state
is reached, a trigger pulse is given or produced at output 65. In
the present example, this storage state is reached after the
recording of a total of nine pulses, i.e., at the starting edge of
the tenth pulse; in other words, the storage 59 totals the pulses
C-D of pulse series C to E (reference series) and the pulses F-H of
the pulse series F to G (trigger series). The state of the count
when H is counted corresponds to the appearance of the trigger
pulse. How many pulses of the reference series and how many of the
trigger series are counted or stored depends both on the time
period s and on the pulse frequency (number of pulses per unit of
time). The pulse frequency is, of course, a function of the
rotatory speed of wheel 50.
So the series of auxiliary pulses consists of the pulses A and K-L,
which occur in the auxiliary pulse transducer 55, while the
reference series and the trigger series (C-E and F-G, respectively)
appear in the main pulse transducer 54.
It is to be noted that the general principle consists in deducting
from the trigger series F-G, at the end of which, at I for example,
the top dead center of the internal combustion engine is located,
going backwards from I for as many pulses as occur during the time
period s; practically, this is accomplished by the fact that the
number of pulses corresponding to the period s which are to be
deducted is fed to the counter or storage before the beginning of
the trigger series that ends preferably at the top dead center. It
is also within the scope of the invention, of course, to enter
additional pulses into the storage or deduct them from the pulses
stored therein, which can be accomplished, for example, by
lengthening or shortening the trigger series that is defined above.
These additional pulses can be used to achieve an additional
displacement of the trigger pulse from the top dead center or the
like.
An embodiment of the invention that differs slightly from FIG. 5 is
represented in FIG. 7. In this case the alignment of the two
transducers in relation to one another and at the same time in
relation to the projections or other pulse-producing elements on
wheel 50 does not have to be performed with the same relative
precision as in the apparatus of FIG. 5, since only the restore
pulse is produced in the second transducer 55.
In detail, the following is the manner of operation:
At the beginning, the projection 51d produces a pulse
simultaneously in transducers 54 and 55. The first and only pulse
in transducer 55 triggers the monostable multivibrator 66. The
rising edge of this pulse is differentiated by the differentiating
circuit RC. The RC constant can be, for example, between 1 and 100
microseconds. This results in a sharp-tipped pulse which passes
through the inverted AND gate 67 and line 68 to the counters or
storages 69 and 70 and restores them to zero. During the time
period s storage 70 counts or stores the pulses from transducer 54,
because the pulse produced in the multivibrator 66 acts through the
inverted AND gates 71 and 72 on the input of the inverted AND gate
73. Then storage 70 stops storing, but storage 69 stores the rest
of the pulses from transducer 54 until it reaches a predetermined
storage state. This storage state corresponds to the total number
of pulses in the reference series. When this storage state is
reached, a pulse again develops in line 74 and acts through gate 72
on the input of gate 73, so that storage 70 resumes counting until
the predetermined final storage state is reached. Then a trigger
pulse is delivered to the output at 75.
In FIG. 8 there is represented another embodiment of the invention,
which will be explained with the aid of FIG. 9 which shows the
pulses that occur at certain terminals or in certain leads in the
system shown in FIG. 8.
In this system, main pulses and auxiliary pulses are obtained from
a single series of projections rather than two series as in the
systems of FIGS. 5 and 7, so that it is no longer necessary to
provide separate projections alongside one another on the
circumference of the wheel to produce the main series and auxiliary
series of pulses. To this end, the transducers 54 and 55 are
arranged in tandem in the direction of movement of the projections,
and the projections themselves are so constructed that the main
pulse series and auxiliary pulse series are intermeshed with one
another, so to speak. This can be brought about by differences in
the width of the projections and the intervals between them. In the
embodiment, for example, the first projection 51f is twice as wide
as the rest of the projections, which all have the same width.
Furthermore, the interval between the ninth projection 51g and the
10th projection 51h is twice as large as the rest of the intervals,
which are all equal to the normal projection width. In the
embodiment according to FIG. 8, a total of 18 projections are
provided.
On the basis of the distribution explained before, the pulse series
III (FIG. 9) is obtained in pulse transducer 54 and pulse series IV
is obtained in pulse transducer 55.
The pulses of the pulse transducers 54 and 55 are delivered to the
inverted AND gate 80a; at the output of the inverter 80b that
follows there occurs a pulse A.sub.2 (pulse series V) that is the
inverse of pulse A.sub.1 or C.sub.1, as the case may be. The pulse
developing between the two last-named gates is differentiated by
the C-R circuit (time constant 1 to 10 microseconds, for example),
so that a spike pulse A.sub.3 develops in line 81, which restores
the counter or storage 82 to zero. The diode 83 short-circuits the
positive spike pulse.
At the same time, pulse A.sub.2 triggers the monostable
multivibrator 84 at whose output 85 there appears a pulse B.sub.1
of the length s.
Furthermore, a pulse F.sub.1 is obtained in line 87 by means of the
inverted OR gate 86 from the pulses occurring in the pulse
transducer 54 and 55, whenever the two transducers fail to deliver
a pulse. The pulse F.sub.1 is differentiated by the differentiating
circuit C.sub.1 -R.sub.1. While the negative spike pulse thereby
produced is being short-circuited by the diode 88, the positive
spike F.sub.2 that is additionally developed controls through
transistor 89 the binary divider 90. When the output 91 of this
divider becomes positive, as represented by F.sub.3 at VII in FIG.
9, the counting of the trigger series F-G begins (see III).
For this purpose, pulse B.sub.1 and pulse F.sub.3 are delivered to
the input of the inverted OR gate 92, so that pulses B.sub.2 and
B.sub.3 (pulse series XI) are produced, in conjunction with the
inverted AND gate 93 (inverter), at the input 94 of the inverted
AND gate 95. While these pulses are occurring at the gate 95, the
pulses of the reference series and trigger series delivered by the
pulse transducer 54 are counted and stored in 82. The trigger pulse
appears at the output 98 when the predetermined storage state is
reached in storage 82, even if storage 82 afterward continues to
count.
In order to bring the binary divider 90 (e.g., Model SN 7473 of
Texas Instruments) into the correct working phase the inverted AND
gate 96 is provided. Whenever the pulse F.sub.3 and pulse A.sub.2
occur simultaneously at the output 91 of the binary divider 90 and
at the output of the inverter 80b, respectively, this AND gate 96
delivers a setting pulse through line 97 to the binary divider 90,
which brings it into the correct working phase.
It should also be noted that an inverted AND gate is also known as
a NAND gate and an inverted OR gate is also known as a NOR
gate.
The apparatus according to the invention can be manufactured in
monolithic integrated circuit form. In particular the transducers
can be included in the monolithic circuit. In this case there is
the possibility of designing the transducers as phototransistors,
certain areas of the monolithic circuit being able to be parts of
the phototransistor. For example, the input transistor of gate 60
or 73 can be constructed as the transducer 54.
Even the production of light to control photosensitive transducers
can be performed by means of luminescent semiconductor material
which, in contrast to incandescent lamps, cannot burn out
(reliability of operation).
Lastly, it is possible for the transducers to be, not
phototransistors, but integrated transistors or generally
broad-surfaced semiconductors which are controled on the basis of
the field effect; that is, the operation of the transducer is
performed by an electrostatic field this being done by means, for
example, of a segmented disk.
The invention, of course, is not restricted to use in explosion
engines, and it can be used wherever similar problems are
encountered. An example of such further use would be the production
of trigger pulses for lighting in the making of photographic wall
pictures in centrifuges of variable rotatory speed.
In FIG. 2, the notation in 12 is "if time between pulses > t +
t', deliver erase pulse;" 13 is a delay; 14 is a divider; the
notation in 17 is "start pulse of length = s follows first pulse;"
the notation in 18 is "lengthing of the impulse to s + the
remainder of the last entered impulse;" the notation in 22 is
"signal for trigger pulse in interval s;" the notation in 23 is
"signal for time base t' when storage 1 and/or storage 3 is on 1'";
in 25 and 27, "Imp. fur" is "pulse when;" the notation in 26 is
"additional erase pulse if trigger and erase pulse do not occur
alternately." Other information with respect to FIG. 2 appears
supra and on the drawing.
* * * * *