GB2028511A - Indicating stages of an operating cycle - Google Patents
Indicating stages of an operating cycle Download PDFInfo
- Publication number
- GB2028511A GB2028511A GB7834078A GB7834078A GB2028511A GB 2028511 A GB2028511 A GB 2028511A GB 7834078 A GB7834078 A GB 7834078A GB 7834078 A GB7834078 A GB 7834078A GB 2028511 A GB2028511 A GB 2028511A
- Authority
- GB
- United Kingdom
- Prior art keywords
- transducer
- signals
- variations
- operating cycle
- flywheel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
- F02P7/00—Arrangements of distributors, circuit-makers or -breakers, e.g. of distributor and circuit-breaker combinations or pick-up devices
- F02P7/06—Arrangements of distributors, circuit-makers or -breakers, e.g. of distributor and circuit-breaker combinations or pick-up devices of circuit-makers or -breakers, or pick-up devices adapted to sense particular points of the timing cycle
- F02P7/067—Electromagnetic pick-up devices, e.g. providing induced current in a coil
- F02P7/0675—Electromagnetic pick-up devices, e.g. providing induced current in a coil with variable reluctance, e.g. depending on the shape of a tooth
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
- H03K17/965—Switches controlled by moving an element forming part of the switch
- H03K17/97—Switches controlled by moving an element forming part of the switch using a magnetic movable element
Abstract
Apparatus for indicating stages of an operating cycle, in which distinguishable variations occur, comprises a transducer providing a series of distinguishable signals each in response to a respective variation. An embodiment for an ignition system for a spark ignition two cylinder internal combustion engine comprises an electro-magnetic transducer (2) situated adjacent to the periphery of a flywheel (1) and responsive to movement of steps (9 and 10) in the periphery of the flywheel past it to supply electrical signals to a control circuit which discharges electrical energy to spark plugs alternately. The threshold of the control circuit to one of these signals is varied in accordance with the frequency of operation to ensure that spurious signals generated when the peripheral portion (6) of the flywheel having a larger diameter is adjacent to the transducer do not trigger the control circuit. <IMAGE>
Description
SPECIFICATION
Method of and means for indicating successive stages of an operating cycle
This invention relates to a method of and means for providing a succession of signals which indicate when respective stages of an operating cycle of an apparatus have been reached.
One kind of apparatus with which the invention may be used to advantage is an internal combustion engine method in accordance with the invention may be used to provide successive signals which indicate when those stages of the operating cycle of an engine have been reached at which respective spark plugs are required to be energised.
Known ignition systems for internal combustion spark ignition engines having a plurality of combustion chambers usually include two distinct means for indicating to the ignition system when there have been reached those stages of the operating cycle of the engine at which respective ones of the spark plugs of the engine are required to be energised. A first of these means usually comprises a rotor arm which moves successively into engagement with contacts connected one with each spark plug and a second means usually comprises a contact breaker. The contact breaker is opened and closed with a frequency twice that of the engine speed and the rotor arm is rotated at a speed half that of the engine.
According to a first aspect of the present invention, there is provided a method of indicating when successive stages of an operating cycle of an apparatus have been reached wherein there is provided a transducer, there occurs a cyclic series of distinguishable variations in the conditions to which the transducer is subjected, said variations corresponding to the successive stages of the operating cycle and the transducer provides a series of distinguishable signals each in response to a respective one of said variations.
With this method, only a single transducer is required to-provide a series of distinguishable signals, each of which indicates that a respective stage of the operating cycle of the apparatus has been reached. By a transducer, we mean herein any device which responds to changes by providing an output signal related to the changes.
Preferably, the signals are fed from the.
transducer to indicating means having a plurality of outputs, output signals are provided at each of said outputs during each cycle of operation of the apparatus, the time at which an output signal is provided is determined by the time at which a corresponding one of said variations occurs and the output or outputs to which said output signal is provided is or are selected according to the distinctive character of the variation.
The indicating means preferably provide output signals at two outputs in response to respective opposite variations in the conditions to which the transducer is subjected. The cyclic series of variations may be brought about by relative movement of the transducer and a member of the apparatus. This movement may be rotation. The transducer may remain stationary in a position adjacent to a rotatable member of the apparatus.
The signals provided by the transducer may differ from one another quantitatively or qualitatively. For example, the transducer may provide electrical signals differing in sign and/or magnitude.
Preferably, each one of the signals provided by the transducer during one operating cycle of the apparatus and corresponding to which an output signal is provided, differs from all of the other signals provided by the transducer during that operating cycle. The series of variations which occurs in each operating cycle and corresponding to which output signals are provided, may consist of two variations only, these being opposite and of equal magnitude.
There may be provided output signals corresponding only those signals from the transducer which exceed a threshold level. The threshold level may be varied according to the operating frequency of the apparatus.
The apparatus may be an internal combustion spark ignition engine, the output signals being fed to respective spark plugs of the engine to energise same at required stages of the operating cycle of the engine.
According to a secpnd aspect of the invention, there is provided apparatus which operates cyclically and includes device for carrying out the method according to the first aspect of the invention. The device preferably comprises a transducer which responds to relative movement of a member of the apparatus and indicating means having a plurality of outputs, the indicating means being connected to the transducer to receive therefrom a series of signals corresponding to successive stages in the operating cycle of the apparatus and being adapted to provide, upon receipt of a signal from the transducer an output signal at an output selected according to a distinguishing characteristic of the signal from the transducer.
The apparatus may be an internal combustion spark ignition engine and the device may be an ignition system.
The indicating means may include means for rejecting signals from the transducer which do not exceed a threshold level. The indicating means may also include means for varying the threshold level according to the operating frequency.
One example of an embodiment of the invention will now be described with reference to the accompanying drawings wherein: FIGURE 1 shows diagrammatically a rotatable member of a cyclically operating apparatus, together with a transducer,
FIGURE 2 is a circuit diagram of indicating means which is connected electrically to the transducer in use,
FIGURE 3 is a circuit diagram of thresholdsetting means which may be incorporated in the indicating means of Figure 2,
FIGURE 4 illustrates the signals produced by the transducer when the rotatable member moves at a relatively high speed, and
FIGURE 5 illustrates the signals produced by the transducer when the rotatable member moves at a lower speed.
The particular example of transducer and indicating means illustrated in the accompanying drawings is intended for use in association with an internal combustion spark ignition engine having two combustion chambers. The engine includes a flywheel 1 which is rotated at a speed called herein the engine speed. The flywheel rotates once during each operating cycle of the engine.
Adjacent to the periphery of the flywheel there is stationarily mounted a transducer 2 which provides a signal at predetermined stages of the operating cycle of the engine. Since the engine has two combustion chambers with respective spark plugs which are required to be energised alternately once during each operating cycle of the engine, the transducer is required to provide two signals during each revolution of the flywheel, the intervals between these signals being equal.
The particular form of transducer illustrated in the accompanying drawings is a variable reluctance generating magnetic pick up. The transducer comprises a winding 3 of electrically conductive wire which embraces a mild steel pole piece 4. Magnetic flux is established in the pole piece by a permanent magnet 5 adjacent to an end of the pole piece remote from the flywheel.
The opposite end of the pole piece is presented towards the flywheel. The flywheel is adapted to vary the magnetic flux to which the winding 3 is subjected whilst the flywheel rotates. The flywheel is formed of mild steel and has a periphery comprising two portions, 6 and 7 respectively which lie on opposite sides of the axis 8 of the flywheel and each subtend at that axis an angle of
1800. The peripheral portion 6 has a radius greater than that of the peripheral portion 7. Thus, there are between the portions 6 and 7 two radially directed steps 9 and 10.
When the peripheral portion 6 of the flywheel is adjacent to the pole piece 4, there is only a small gap between the pole piece and the periphery of the flywheel. When the peripheral portion 7 of the flywheel is adjacent the pole piece, there is a larger gap between the pole piece and the flywheel. If the flywheel is rotated in the direction of the arrow 11 shown in Figure 1, as the step 9 of the flywheel passes the pole piece 4, there is an increase in the magnetic flux to which the winding 3 is subjected and when the step 10 passes the pole piece, there is a decrease in the magnetic flux to which the winding is subjected. These variations in magnetic flux cause corresponding electrical signals to pass from the transducer to the signalling means illustrated in Figure 2.
The sign of the electrical signals which pass from the transducer to the signalling means depends upon whether the variation in magnetic flux which causes the electrical signal is an increase or a decrease. The magnitude of the electrical signals which pass from the transducer
to the indicating means depends upon the speed
of relative movement of the flywheel and
transducer. In Figure 4, there are represented the
electrical signals produced by the transducer
when the flywheel is rotating at a higher speed. In
Figure 5, there is represented the signals produced
by the transducer when the flywheel is rotating at
a lower speed.It will be seen that when the
peripheral portion 6 of the flywheel is adjacent to
the pole piece 4 spurious electrical signals are
produced by the transducer but these spurious
signals are small, as compared with the signals
resulting from movement of the steps 9 and 10
past the pole piece 4 when the flywheel is rotating
at the same speed. However, the spurious signals
produced when the flywheel is rotating at high
speed are of the same order of magnitude as the
signals produced by the steps 9 and 10 when the flywheel is rotating at low speed. As can be seen from Figures 4 and 5, the signal produced by the transducer when the step 9 passes the pole piece 4 is distinguishable from the signal prodUced by the transducer when the step 10 passes the pole piece, at all speeds of the flywheel.
The indicating means has a plurality of outputs, two in the particular example illustrated since the engine has two combustion chambers. These outputs are constituted by electrical leads 1 2 and 13 which are connected to respective spark plugs (not shown) of the engine. The indicating means further comprises two ignition coils, 14 and 1 5, each having a primary winding and a secondary winding. The secondary windings are connected to respective ones of the leads 12 and 13. The primary winding of each ignition coil is connected in series with a respective capacitor 1 6 and thyristor 1 7. When either one of the thyristors is in a non-conducting condition, the associated capacitor 1 6 is charged by a charging circuit (not shown) connected to the capacitor via a respective diode 18.When either one of the thyristors 1 7 assumes a conducting condition, the associated capacitor is discharged through the primary winding of the associated ignition coil and a high voltage output signal is provided to the corresponding spark plug.
The indicating means further includes an electronic switch 1 9 which receives the electrical signals produced by the transducer 2, these signals being fed aiong electrical conductors 20 and 21. The particular example of switch illustrated has two outputs 22 and 23 respectively. The outputs 22 and 23 are each connected via a coupling capacitor 24 to the control electrode of a respective one of the thyristors 17.
When an electrical signal corresponding to passage of one of the steps 9 and 10 past the pole piece 4 is fed to the switch 19, there is produced at one only of the outputs 22 and 23 a positive signal which sets the associated thyristor in a conducting condition. When an electrical signal of opposite sign is fed from the transducer to the switch 1 9, there is provided at the other one of the outputs 22 and 23 a signal which sets the other thyristor in a conducting condition.
In order to avoid the thyristors 17 being set in a
conducting condition by spurious signals produced
by the transducer 2 when the peripheral portion
1 6 of the flywheel is adjacent to the pole piece 4,
there is interposed in an appropriate one of the
conductors 20 and 21 the threshold setting
means illustrated in Figure 3. The threshold
setting means comprises a transistor 25 which
controls the passage of signals to the switch 1 9 so
that a signal reaches the switch 19 only if that
signal has an amplitude exceeding a threshold at
and below which the transistor 25 remains in a
non-conducting condition. Signals having a
magnitude which do not exceed this threshold are
rejected. The value of the threshold is determined
by the charge on a capacitor 26 connected to the
emitter of the transistor 25.A charge is applied to
the capacitor 26 by each signal of appropriate sign
produced by the transducer and the charge leaks
away continuously through 9 resistor 27. The
charge on the capacitor therefore depends on the
frequency with which signals of appropriate sign
are produced by the transducer and therefore
upon the operating frequency of the engine. At
high engine speeds, the charge on the capacitor
26 is relatively large and the threshold is
correspondingly high. At low engine speeds, the
threshold is low because the charge on the
capacitor 26 is small.
To avoid energisation of one or other of the
spark plugs at an incorrect stage of the operating
cycle of the engine, it is necessary to vary the
threshold level only for those pulses of the same sign as the pulse produced when the stlp 10
passes the pole piece 4. Significant spurious
signals are produced only when the peripheral
portion 6 of the flywheel is adjacent to the pole
piece. Whilst this peripheral portion is adjacent to the pole piece, the switch 1 9 is in a state to which
it has been set by the step 9. It is merely
necessary to avoid the switch being set in its other
state by spurious signals. Any spurious signals
produced by the transducer when the peripheral
portions 7 of the flywheel is adjacent to the pole
piece 4 are not of sufficient magnitude to operate the switch 19.
Claims (17)
1. A method of indicating when successive stages of an operating cycle of an apparatus have been reached wherein there is provided a transducer, there occurs a cyclic series of distinguishable variations in the conditions to which the transducer is subjected, said variations corresponding to the successive stages of the operating cycle, and the transducer provides a series of distinguishable signals each in response to a respective one of said variations.
2. A method according to claim 1 wherein signals are fed from the transducer to indicating means having a plurality of outputs, output signals are provided at each of said outputs during each cycle of operation of the apparatus, the time at which an output signal is provided is determined by the time at which a corresponding one of said variations occurs and the output or outputs to which said output signal is provided is or are selected according to the distinctive character of the variation.
3. A method according to claim 2 wherein the indicating means provides outout signals at two outputs in response to respective opposite variations in the conditions to which the transducer is subjected.
4. A method according to any preceding claim wherein said cyclic series of variations is brought about by relative movement of the transducer and a member of the apparatus.
5. A method according to claim 4 wherein the transducer remains stationary in a position adjacent to a rotatable member of the apparatus which subjects the transducer to said cyclic series of distinguishable variations.
6. A method according to claim 2 wherein each one of the signals provided by the transducer during one operating cycle of the apparatus and corresponding to which an output signal is provided differs from all of the other signals provided by the transducer during that operating cycle.
7. A method according to claim 6 wherein the series of variations which occurs in each operating cycle and corresponding to which output signals are provided consists of two variations only, these being opposite and of equal magnitude.
8. A method according to claim 2 or any of claims 3 to 7 as appendant thereto wherein there are provided output signals corresponding only to those signals from the transducer which exceed a threshold level.
9. A method according to claim 8 wherein the threshold level is varied according to the operating frequency of the apparatus.
10. Apparatus which operates cyclically and includes a device for carrying out a method according to any preceding claim.
11. Apparatus according to claim 10 wherein the device comprises a transducer which responds to relative movement of a member of the apparatus and indicating means having a plurality of outputs, the indicating means being connected to the transducer to receive therefrom a series of signals corresponding to successive stages in the operating cycle of the apparatus and being adapted to provide, upon receipt of a signal from the transducer, an output signal at an output selected according to a distinguishing characteristic of the signal from the transducer.
12. Apparatus according to claim 11 wherein the indicating means includes means for rejecting signals from the transducer which do not exceed a threshold lever.
1 3. Apparatus according to claim 12 wherein the indicating means further includes means for varying the threshold level according to the operating frequency.
14. Apparatus according to any one of claims 10 to 13 which is an internal combustion spark ignition engine and wherein said device is an ignition system.
1 5. A method according to claim 1 substantially as herein described with reference to the accompanying drawings.
16. An internal combustion spark ignition engine having an ignition system substantially as herein described with reference to and as illustrated in the accompanying drawings.
17. Any novel feature or combination of features disclosed herein.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7834078A GB2028511A (en) | 1978-08-19 | 1978-08-19 | Indicating stages of an operating cycle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7834078A GB2028511A (en) | 1978-08-19 | 1978-08-19 | Indicating stages of an operating cycle |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2028511A true GB2028511A (en) | 1980-03-05 |
Family
ID=10499191
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7834078A Withdrawn GB2028511A (en) | 1978-08-19 | 1978-08-19 | Indicating stages of an operating cycle |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2028511A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0046006A2 (en) * | 1980-07-19 | 1982-02-17 | LUCAS INDUSTRIES public limited company | Electromagnetic transducer |
| EP0058498A1 (en) * | 1981-02-18 | 1982-08-25 | LUCAS INDUSTRIES public limited company | Position transducer |
| EP0066975A2 (en) * | 1981-06-05 | 1982-12-15 | LUCAS INDUSTRIES public limited company | Internal combustion engine function control system |
| DE3305217C1 (en) * | 1983-02-16 | 1984-07-19 | Dornier System Gmbh, 7990 Friedrichshafen | Device for measuring angles and displacements in a servo-system |
| EP0905375A2 (en) * | 1997-09-30 | 1999-03-31 | Toyota Jidosha Kabushiki Kaisha | Crank angle detecting apparatus of internal combustion engine |
-
1978
- 1978-08-19 GB GB7834078A patent/GB2028511A/en not_active Withdrawn
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0046006A2 (en) * | 1980-07-19 | 1982-02-17 | LUCAS INDUSTRIES public limited company | Electromagnetic transducer |
| EP0046006A3 (en) * | 1980-07-19 | 1983-01-05 | Lucas Industries Public Limited Company | Electromagnetic transducer |
| EP0058498A1 (en) * | 1981-02-18 | 1982-08-25 | LUCAS INDUSTRIES public limited company | Position transducer |
| EP0066975A2 (en) * | 1981-06-05 | 1982-12-15 | LUCAS INDUSTRIES public limited company | Internal combustion engine function control system |
| EP0066975A3 (en) * | 1981-06-05 | 1983-07-20 | Lucas Industries Public Limited Company | Internal combustion engine function control system |
| US4485785A (en) * | 1981-06-05 | 1984-12-04 | Lucas Industries | Internal combustion engine function control system |
| US4531090A (en) * | 1981-06-05 | 1985-07-23 | Lucas Industries | Position transducer for an internal combustion engine function control system |
| DE3305217C1 (en) * | 1983-02-16 | 1984-07-19 | Dornier System Gmbh, 7990 Friedrichshafen | Device for measuring angles and displacements in a servo-system |
| EP0905375A2 (en) * | 1997-09-30 | 1999-03-31 | Toyota Jidosha Kabushiki Kaisha | Crank angle detecting apparatus of internal combustion engine |
| EP0905375A3 (en) * | 1997-09-30 | 2002-10-23 | Toyota Jidosha Kabushiki Kaisha | Crank angle detecting apparatus of internal combustion engine |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |