US3739759A

US3739759A - Rotation sensing pulse control generator for triggered ignition systems and the like

Info

Publication number: US3739759A
Application number: US00223640A
Authority: US
Inventors: R Sleder
Original assignee: Brunswick Corp
Current assignee: Brunswick Corp
Priority date: 1972-02-04
Filing date: 1972-02-04
Publication date: 1973-06-19
Anticipated expiration: 1990-06-19
Also published as: FR2170678A5; SE390193B; CA968841A; AU5140273A; AU473040B2; BE794575A; GB1411716A

Abstract

A capacitor discharge ignition system includes a main controlled rectifier in series with a capacitor to discharge the capacitor into the spark plug through a suitable pulse transformer. A pilot controlled rectifier connects a firing winding to the gate of the main rectifier. A second control winding, connected to the gate of the pilot rectifier, is mounted in spaced relation to the firing winding. A common magnet is rotated in synchronism with the engine. Only one direction of rotation generates the pulses in proper sequence to the two controlled rectifiers.

Description

SYSTEMS AND THE LIKE [75] Inventor: Richard L. Sleder, Fond du Lac,

' Wis.

[73] Assignee: Brunswick Corporation, Chicago, Ill.

22 Filed: Feb. 4, 1972 [21] Appl. No.: 223,640

' United States Patent 11 1 1111 3,739,759 S leder 1 June 19, 1973 4] ROTATION SENSING PULSE CONTROL 3,280,810 10/1966 Worrell 123/148 GENERATOR FOR TRIGGERED IGNITION 3,599,615 8/1971 Foreman 123/148 Primary ExaminerLaurence M. Goodridge Assistant Examiner-,Romld B. Cox Attorney Andrus, Sceales, Starke et al 57 ABSTRACT 11 Claims, 4 Drawing Figures TIMING ENGINE Patented June 19, 1973 III TIMING CONTROL FIGA ENGINE FIGJ ROTATION SENSING PULSE CONTROL GENERATOR FOR TRIGGERED IGNITION SYSTEMS AND THE LIKE BACKGROUND OF THE INVENTION The present invention relates to a pulse control generator for controlling triggered ignition systems and the like and particularly to the discharging of a capacitor discharge ignition system in proper timed relation for establishing undirectional rotation of an internal combustion engine.

Solid state ignition systems have been developed to eliminate the conventional induction coil and breaker point ignition system for internal combustion engines. Solid state devices have advantages in providing reliable, long life units through the use of solid state switching circuits. Further capacitor discharge ignition systems have been proposed wherein a capacitor is charged to a firing voltage and then discharged at an appropriate time through a pulse transformer to the firing means such as a spark plug to produce the desired ignition energy. Capacitor discharge ignition systems provide a rapidly rising and short duration pulse with improved ignition. Many systems have also been suggested for eliminating the breaker point type switch and substituting therefor a solid state switch such as a thyrister in combination with a pulse generator driven in synchronism with the internal combustion engine.

Although such systems are generally highly satisfactory, a two cycle engine will operate in both the forward or reverse direction as a result of the ignition pulses. This is undesirable in many instances as it does not provide for a controlled drive condition. Applicant has found that it is a particular problem in connection with high performance two cycle internal combustion engines for outboard motors where accidental operation of the engine in other than the forward direction results in dangerous operation of the outboard marine apparatus or boat.

SUMMARY OF THE PRESENT INVENTION ergy from a suitable power source to the spark plug.

Thus, a controlled rectifier can be connected in series with a capacitor to discharge the capacitor into the I spark plug through a suitable pulse transformer. The

capacitor is of course charged from any suitable source such as an alternator, a battery and a step-up converter or the like. The gated switch means is connected to the firing winding of an alternator means by a second gated switch means such as a pilot controlled rectifier or the like. The alternator output is sufficient to trigger the first gated switch means if the second switch means is turned on to thereby provide for discharge of the capacitor or other transfer of power. A second control or direction sensing winding is mounted in spaced relation to the firing winding and the output is interconnected to control the firing of the pilot switch means. If rotation is in a proper direction, the direction sensing winding will provide an output signal to the pilot switch means permitting operation of the triggering circuit. The opposite rotation however first generates the pulse in the trigger or firing winding. At this time, however, the pilot switch means is off and the energy is dissipated within the winding and/or associated circuitry between the pilot switch means and the firing winding. Only after the energy has been dissipated does the direction sensing winding receive a pulse to turn on the related pilot switch. However, there is insufficient, if any, energy to transfer and to turn on the main control switch and, consequently, the system will positively prevent transfer of energy through the firing or ignition system.

The firing winding and the sensing winding are preferably wound as part of a common alternator with a common rotor or magnetic means. Thus the windings are mounted in spaced relation for sequential time spaced coupling with the common magnet.

In a particularly novel circuit the firing winding is connected to the gate of a main controlled rectifier in series with a pilot controlled rectifier. The rotation sensing winding is connected across the gate to cathode circuit with a holding capacitor such that the output of the sensing winding biases the controlled rectifier to conduct and provides a holding charge on the capacitor to positively hold the controlled rectifier on while the magnet moves into coupling with and generates the control pulse within the firing winding.

Applicant has found that this invention provides a simple and inexpensive direction sensing control which will positively prevent erroneous reverse operation of an internal combustion engine forming a part of an outboard motor or the like.

BRIEF DESCRIPTION OF DRAWING DESCRIPTION OF ILLUSTRATED EMBODIMENT Referring to the drawing and particularly to FIG. 1, an ignition system for an internal combustion engine is illustrated. The invention is particularly applicable to an engine 1 which is a two cycle, high performance engine such as employed in outboard motors and is diagrammatically shown as a two cylinder having separate plugs 2 as the firing means for ea ch cylinder. Firing power is supplied to the respective-spark plugs 2 from a common capacitor 3 which' i's'connected in acharging circuit to a suitable DC power supply 4. Capacitor 3 -is selectively connected to fire the spark plugs 2 through a common transformer 5 and distributor 6. A suitable automatic ignition advance means 7 is provided to vary the ignition timing withengine speed. Alternatively, of course, other construction, such as direct, paralleled circuits, might be employed.

A silicon controlled rectifier 8 provides a gate or triggered switch means interconnected in series with the positive side of the capacitor 3 to one side of the primary winding 9 of the pulse transformer 5. The opposite side of the winding 9 is connected directly to the opposite side of the capacitor 3. The secondary 10 of the pulse transformer 5 is connected to the distributor 6 and selectively to the spark plug 2.

The controlled rectifier S has an input gate 11 operatively connected to a trigger alternator unit 12 for controlled firing of the control rectifier 8 and thus the transfer of the energy stored in the capacitor 3 to the spark plugs 2.

The illustrated alternator unit 12 is a permanent magnet alternator including a rotor 13 coupled to and driven in synchronisrn with the engine 1. The rotor 13 includes a pair of diametrically spaced permanent magnets 14, one for each cylinder, mounted to rotate with the rotor 13 and having a north and a south pole. The rotor moves past a stator unit 15 including a trigger or firing winding 16 and a trigger control or direction sensing winding 17 wound on

separate cores

18 and 19, respectively. The winding 16 and the trigger direction sensing winding 17 are mounted in physically circumferentially spaced relation adjacent to the rotor 13 and are close coupled to each of the magnets 14 through the

magnetic cores

18 and 19 to provide a relatively high degree of coupling.

The winding 16 has its one side grounded in common with the cathode of the main rectifier 8. The opposite end of the winding 16 is connected to the gate 11 of the main rectifier 8 through a series connected pilot controlled rectifier 20 and a gate resistor 21. The output of the firing winding 16 has an amplitude at least equal to the voltage drop across the anode to cathode barrier of the pilot controlled rectifier 20 when the latter is conducting and the gate to cathode voltage requirement of the main controlled rectifier 8.

In the illustrated embodiment of the invention, transient

protective capacitors

22 and 23 are provided between the opposite sides of the gate resistor 21 and ground. In addition, a clamping diode 24 is shown connected between the gate and ground to limit the maximum voltage applied across the gate to cathode circuit of the main control rectifier 8.

Thus, with the rectifier 20 biased to conduct, the output of the firing winding 16 is applied to the gate to cathode circuit of the main controlled rectifier 8 and causes it to conduct and discharge the capacitor 3 for firing of the associated spark plug 2.

In accordance with the present invention, the trigger control or direction sensing winding 17 is connected to fire the pilot controlled rectifier 20. The sensing winding 17 has one side connected via a diode 25, in the illustrated embodiment of the invention, to the gate 26 of the controlled rectifier 20. The cathode of the rectifier 20 is connected directly to the opposite side of the winding 17. Thus, when the gate connected side of the sensing winding 17 is positive, the controlled rectifier 20 is biased to conduct.

A holding capacitor 27 is connected directly across the gate to cathode circuit of rectifier 20 and thus in parallel to the output of the control winding 17 through the series connection to the diode 25. During the conducting period, the capacitor 27 is charged. After the magnet 14 moves past or the polarity of the winding 17 reverses, the capacitor 27 will maintain a timed, momentary power supply to the gate to cathode circuit of the controlled rectifier 20. During this period, the magnet 14 moves into and past the trigger winding 16 to generate a firing pulse which is applied via the rectifier 20 to the gate 11 of the main rectifier 8.

In the illustrated embodiment of the invention, the forward rotation of the rotor 13, associated with the forward rotation of the engine results in the sequential coupling to winding 17 and then winding 16 to first fire pilot controlled rectifier 20 to complete the circuit to gate 11 and then generate the trigger power pulse as a result of the coupling between the magnet 14 and the trigger winding 16. This results in firing of rectifier 8 and discharge of the capacitor 3 to the appropriate spark plug 2. For example, referring to FIGS. 2 and 3, the pulse output of the

windings

16 and 17 are shown for open circuit and loaded circuit operation with forward direction of rotation. The two

windings

16 and 17 generate essentially similar time spaced

alternating pulses

29 and 30, although unidirectional pulse signals may be formed by appropriate design. Under load circuit connection, shown in FIG. 1, the positive half cycle of the pulse 30 in the sensing winding 17 is substantially shorted, as shown at 31 in HQ 3, by the diode 25 and the gate to cathode drop of the pilot rectifier 20, with a turnon of the rectifier 20. Simultaneously, the capacitor 27 charges to the voltage level across the gate to cathode circuit to maintain the rectifier on. The negative half cycle appears in winding 17 but is blocked by diode 25. Shortly, thereafter, the firing pulse 29 is generated in winding 16, the positive half of which is transferred via the pilot rectifier 20 to the gate circuit of the main firing rectifier 8.

In the event a reverse rotation of the engine should occur for any reason, the magnet 14 moves past the firing winding 16 prior to coupling to the sensing winding 17, with the reverse sequence of

pulses

29 and 30, as shown in FIG. 4. When magnet 14 moves past the firing winding 16 the pulse 29 is blocked by the rectifier 20 and the energy is dissipated within the winding 16 and core 18 as the result of the blocking state of the pilot controlled rectifier 20. The magnet 14 will, of course, subsequently move past the sensing winding 17 and produce a turn-on signal pulse 30 to the pilot controlled rectifier 20. However, when it does create such a signal, the energy of the firing winding 16 will already have been dissipated, and, consequently, the firing of the controlled rectifier 20 does not affect a triggering of the main controlled rectifier 8. The system thereby operates to positively prevent transfer of energy to the spark plugs 2 during the reverse rotation.

In the illustrated embodiment of the invention the firing winding 16 and the sensing winding 17 are shown coupled to a common magnet. If desired completely separate magnetic devices might be provided through the use of a synchronized drive assembly. Further, although shown as conductive connections, other electrical circuit connections can, of course, be employed to interconnect the windings to control the transfer of power. For example, a suitable switching means in combination with a power amplifier and/or auxiliary supplies may be employed. Thus the illustrated embodiment of the invention shows a preferred construction of the rotation direction sensing control means for actuating of a solid state ignition system or the like. However, the preferred construction does not limit the broad application of the concept of providing the sequential signal generation including a control firing signal and a trigger powering signal generated in suitable time spaced relationship and being directly rotation sensitive.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims, particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

1. An ignition system for selectively supplying power to an internal combustion engine comprising a first and second gated switch means, and first and second pulse generating means generating first and second pulse trains, said second gated switch means connecting said first gated switch means to said first pulse generating means, said second pulse generating means being connected to actuate said second switch means, the pulse trains of said first and second pulse generating means producing and including timed spaced pulse signals with the related signals offset and with the sequence being directly related to the direction of engine rota tion and whereby the second plate generating means generates a pulse signal immediately prior to the generation of a pulse signal from the first pulse generating means in response to forward rotation to provide for transfer of the pulse of the first generating means to the first switch means.

2. The ignition system of claim 1 having a main power supply means, said gated switch means are solid state rectifiers having control gates and connecting such power supply means to fire the engine, said second rectifier being connected in series with the first pulse generating means to the gate of the first rectifier, and said second pulse generating means being connected to the gate of the second rectifier.

3. The ignition system of claim 1 wherein said first and second pulse generating means include corresponding first and second windings mounted in spaced relation to each other and having a common magnetic means sequentially coupled to the first and second windings for producing said timed spaced pulse trains.

4. The ignition system of claim 1 wherein said switch means are gated controlled rectifier means, and said second pulse generating means includes a timing means responsive to establishment of each pulse signal of the corresponding train to operatively prolong such signal to overlap with a subsequently generated corresponding signal of the first pulse generating means in response to said forward engine rotation.

5. The ignition system of claim 4 wherein said timing means includes a holding capacitor connected to said second pulse forming means in series with a blocking diode.

6. The ignition system of claim 1 including an ignition capacitor, a power supply connected to said ignition capacitor for charging of said capacitor to a preselected firing voltage, a pulse transformer having an output adapted to be connected to fire the engine, said first switch means being a firing controlled rectifier connected in series with said capacitor and said pulse transformer.

7. The ignition system of claim 1 having a main power supply means, said first gated switch means being a firing controlled rectifier having a gate and connecting such power supply means to fire the engine, a pulse generating means, said second gated ,switch means being a pilot controlled rectifier having a gate and connecting the first pulse generating means to the gate of the firing controlled rectifier, said second pulse generating means being connected to the gate of said second pilot controlled rectifier, and said second pulse generating means including means to extend the length of each pulse signal to maintain the pilot rectifier on for a selected period to provide for transfer of the pulse of the first generating means to the firing rectifier in response to said forward rotation.

8. The ignition system of claim 1 wherein said first and second pulse generating means includes a permanent magnet rotor and a dual winding stator, said rotor being coupled to be driven in synchronism with the operation of the engine and including at least one permanent magnet, said stator assembly being mounted adjacent said rotor and adjacent the path of said magnet, said stator assembly including a pair of circumferentially spaced windings including a firing winding and a direction sensing winding mounted in circumferentially spaced relation and separated by an angle substantially less than said sensing winding being mounted to couple to said magnet prior to the coupling of the firing winding to said magnet in response to forward engine rotation and subsequently in response to reverse engine rotation.

9. The ignition system of claim 2 wherein said first and second switch means are a firing controlled rectifier and a pilot controlled rectifier connected between the firing winding and the gate of the firing controlled rectifier, the opposite end of the firing winding and the cathode of the firing controlled rectifier being connected to each other, a diode connecting one side of the sensing winding to the gate of the pilot controlled rectifier, and the opposite end of said sensing winding being connected directly to the cathode of the pilot controlled rectifier, a holding capacitor connected directly across the gate to cathode of the pilot controlled rectifier, the spacing between said firing winding and said sensing winding being such that the pilot controlled rectifier is fired by the coupling of the permanent magnet of the rotor with the sensing winding to establish and maintain conduction through the pilot controlled rectifier during the movement of the magnet through the angle to the firing winding and being sufficient to substantially dissipate the energy in the firing winding in response to opposite rotation of the rotor unit prior to the coupling of the magnet to the sensing winding.

10. An ignition system for an internal combustion engine, a pulse transformer having an output adapted to fire the engine, a firing controlled rectifier connected in series with said pulse transformer to control conduction therethrough, a control generating assembly including a permanent magnet rotor and a dual winding stator, said rotor being coupled to be driven in synchronism with the operation of the engine and including at least one permanent magnet, said stator assembly being mounted adjacent said rotor and adjacent the path of said magnet, said stator assembly including a pair of circumferentially spaced windings including a firing winding and a direction sensing winding mounted in circumferentially spaced relation and separated by an angle substantially less than 180, said sensing winding being mounted to lead the engagement with said magnet prior to the coupling of the firing winding to said magnet, a pilot controlled rectifier connected between the firing winding and the gate of the firing controlled rectifier, a diode means connecting said sensing winding to the gate of the pilot controlled rectifier, a timing cient to substantially dissipate the energy in the firing winding in response to opposite rotation of the rotor unit prior to the coupling of the magnet to the sensing winding.

11. The ignition system of claim 10 wherein said timing means is a capacitor connected in parallel with the sending winding and said diode means in series connec-

Claims

1. An ignition system for selectively supplying power to an internal combustion engine comprising a first and second gated switch means, and first and second pulse generating means generating first and second pulse trains, said second gated switch means connecting said first gated switch means to said first pulse generating means, said second pulse generating means being connected to actuate said second switch means, the pulse trains of said first and second pulse generating means producing and including timed spaced pulse signals with the related signals offset and with the sequence being directly related to the direction of engine rotation and whereby the second plate generating means generates a pulse signal immediately prior to the generation of a pulse signal from the first pulse generating means in response to forwarD rotation to provide for transfer of the pulse of the first generating means to the first switch means.

7. The ignition system of claim 1 having a main power supply means, said first gated switch means being a firing controlled rectifier having a gate and connecting such power supply means to fire the engine, a pulse generating means, said second gated switch means being a pilot controlled rectifier having a gate and connecting the first pulse generating means to the gate of the firing controlled rectifier, said second pulse generating means being connected to the gate of said second pilot controlled rectifier, and said second pulse generating means including means to extend the length of each pulse signal to maintain the pilot rectifier on for a selected period to provide for transfer of the pulse of the first generating means to the firing rectifier in response to said forward rotation.

8. The ignition system of claim 1 wherein said first and second pulse generating means includes a permanent magnet rotor and a dual winding stator, said rotor being coupled to be driven in synchronism with the operation of the engine and including at least one permanent magnet, said stator assembly being mounted adjacent said rotor and adjacent the path of said magnet, said stator assembly including a pair of circumferentially spaced windings including a firing winding and a direction sensing winding mounted in circumferentially spaced relation and separated by an angle substantially less than 180*, said sensing winding being mounted to couple to said magnet prior to the coupling of the firing winding to said magnet in response to forward engine rotation and subsequently in response to reverse engine rotation.

10. An ignition system for an internal combustion engine, a pulse transformer having an output adapted to fire the engine, a firing controlled rectifier connected in series with said pulse transformer to control conduction therethrough, a control generating assembly including a permanent magnet rotor and a dual winding stator, said rotor being coupled to be driven in synchronism with the operation of the engine and including at least one permanent magnet, said stator assembly being mounted adjacent said rotor and adjacent the path of said magnet, said stator assembly including a pair of circumferentially spaced windings including a firing winding and a direction sensing winding mounted in circumferentially spaced relation and separated by an angle substantially less than 180*, said sensing winding being mounted to lead the engagement with said magnet prior to the coupling of the firing winding to said magnet, a pilot controlled rectifier connected between the firing winding and the gate of the firing controlled rectifier, a diode means connecting said sensing winding to the gate of the pilot controlled rectifier, a timing means connected to said sensing winding and connected to the gate of the pilot controlled rectifier to fire said rectifier, the spacing between said firing winding and said sensing winding being such that the pilot controlled rectifier is fired by the coupling of the permanent magnet of the rotor with the sensing winding to establish and maintain conductivity through the pilot controlled rectifier during the movement of the magnet through the angle to the firing winding and being sufficient to substantially dissipate the energy in the firing winding in response to opposite rotation of the rotor unit prior to the coupling of the magnet to the sensing winding.

11. The ignition system of claim 10 wherein said timing means is a capacitor connected in parallel with the sending winding and said diode means in series connection.