RU2174187C2 - Ignition system - Google Patents

Abstract

FIELD: mechanical engineering; ignition systems of internal combustion engines. SUBSTANCE: modular electronic ignition system is designed for internal combustion engines. System uses pickups operating on principle of Hall-effect device and provided with pawl. Two permanent magnets are secured on element made of iron-free material and mounted on camshaft which passes through oil seal installed in cover of ignition timing control unit. Module of sensitive elements has pickups operating as Hall-effect devices. Pickups are spaced circumferentially being arranged around element with permanent magnets. Pickups reveal presence of magnetic field when magnets pass near pickups operating on principle of Hall-effect devices. Operation time delay is adjusted by changing angular distance through which magnets are displaced relative to each other. Output signals of Hall-effect devices energize integrated circuits providing switching on of ignition coil at primary winding side. EFFECT: cheap and simple device shielding electromagnetic interferences, easy to demount and replace system elements. 17 cl, 6 dwg

Description

 The present invention relates to ignition systems that are used in internal combustion engines and, in particular, to an ignition system for an internal combustion engine in which solid-state magnetically sensitive elements are used.

 The ignition of the fuel-air mixture in internal combustion engines by an electric spark is carried out in various ways. However, regardless of the system used, there is a fundamental requirement for providing a high voltage pulse and supplying it to the spark plugs with an energy reserve sufficient to form an electric arc between the central electrodes and the ground electrodes in the spark plugs. In this case, a high voltage pulse must be supplied to each candle at a given point in time and for a given period of time. In modern systems, a sensor or switching means is usually used, which determines, depending on the angular position of the crankshaft, the moment when the piston in a certain cylinder enters the process of the engine cycle’s working stroke and transmits this information in a certain way. A high voltage circuit with a high-current switching device is used to power the primary winding of the ignition coil, and a high voltage pulse is supplied to the spark plugs from the secondary winding. One of the disadvantages of the known systems is that it is necessary to shield the ignition circuit from radio frequency interference. Poor shielding can lead to system failure or malfunction, in particular, this is especially true for systems that use a microprocessor. High voltage wires, i.e. the wires connected to the spark plugs must also be shielded so as not to affect the ignition circuit or circuit, as well as other electronic devices, such as a car stereo or telephone.

 There are sensitive and trigger means that determine the angular position of the engine crankshaft, either directly or indirectly. Currently, inductive sensors are most commonly used. Inductance detection requires that there is a change in the magnetic field near the sensor. Although a change in magnetic flux induces a voltage in the conductor, however, magnetically sensitive devices are not always "inductive" in this sense. The magnetic field can be used to influence the sensor output signal, in the case when the magnitude, and not the change in the field flux, causes the sensor output signal to change. Elements and devices based on the use of the effect are examples of solid-state magnetosensitive devices that do not work on the principle of the rate of change of the induced voltage. In the case of these devices, a magnetic field perpendicular to the current vector causes a potential difference in the conductor or semiconductor. The resulting voltage is called Hall. The output voltage on the sensor of this type, which is a consequence of the Hall voltage, does not depend on the rate of change of the magnetic field, which is determined by the sensor.

 The advantages of using a Hall-based device compared to other magnetic means designed to determine the angular position of the crankshaft are: (1) minimum block sizes, (2) low cost, (3) minimum number of elements, (4) clear actuation, (5) sufficient resistance against the influence of surrounding sources.

 Latched Hall effect devices have the advantage that time intervals can be set using two miniature permanent magnets. This is the difference compared to the external means used with a stretched output signal operating without a latch, which are well known. In known solutions, devices operating according to the Hall principle are used, which are a bipolar type device with two outputs, and this device is located between a pair of opposed permanent magnets. Two magnetic fields of the same magnitude are generated by the Hall device, excluding the impact on this device. On the disk mounted on the crankshaft, metal contacts are fixed, arranged in a certain way and designed to bypass the magnetic field between one and then the other magnets and the Hall device at predetermined intervals, ensuring the device is triggered by the residual magnetic field of the sensor. One of the outputs of the bipolar Hall device, depending on which field is shunted, transmits the sensor output signal to one of the two input channels of the microprocessor. The corresponding output channel of the microprocessor is an input for the winding of the master device, the ignition coil, and then for the device generating a spark in two of the four cylinders. Response delay time, i.e. the time during which the primary winding is fed to saturation before the disappearance of the magnetic field in the ignition coil, thereby inducing a high-voltage pulse in the secondary winding, which is grounded through the spark plugs, is determined by the length of the metal contact. The longer the contact length, the longer the Hall effect device will create a Hall voltage, which feeds the primary winding through an intermediate circuit. Similarly, a single magnet and two separate devices operating according to the Hall principle act in the same way. In both cases, the sensor is designed to determine the angular position of the crankshaft in the direction of its rotation. Since the crankshaft makes two full revolutions per stroke in a given cylinder of a four-stroke engine, the ignition coil or ignition coils fire twice during a full engine cycle in a particular cylinder. One of the triggers occurs between the exhaust and intake strokes, and it is useless. In fact, this doubles the required system load.

 Solid-state ignition systems are also known that use a switching device that operates according to the Hall principle without a latch and which is a means for determining the ignition timing ahead or delayed. The Hall device is activated by a DC bias voltage, which is induced in the coil by permanent magnets mounted on a rotating element of a small single-cylinder engine with magneto ignition. The use of the Hall switch in this case is fundamentally different from the option described above. Examples of the devices presented above are described in US Pat. Nos. 4,155,340, 4,508,092, 4,406,272, 5,158,056, 5,015,005, 4,903,674, 3,556,068, 2,768,227, 4,918,569, 5,113,839, 3,587,549, 2,811,672 and 3,621,827. In addition, similar devices are discussed in French patents 2,422,044 and US 2,675,415 and 2,462,491.

 The aim of the present invention is to provide an improved solid-state non-contact ignition system for internal combustion engines.

 Another objective of the present invention is to provide an improved solid-state non-contact ignition system for internal combustion engines having a simpler and more reliable design.

 Another objective of the present invention is to provide an improved solid-state non-contact ignition system for model-type internal combustion engines, which makes it possible to quickly and easily dismantle and replace system elements.

 It is also an object of the present invention to provide an improved solid-state non-contact ignition system for internal combustion engines having a simplified radio interference shielding device.

 These and other goals are achieved using a system with an inductive sensitive element and using four integrated circuits operating according to the Hall principle with a latch, with miniature permanent magnets mounted on a cam shaft, with four windings of the master device with corresponding integrated circuits, as well as two devices instant response modular type.

 Other objects and features of the present invention will be apparent from the following detailed description of a preferred embodiment.

The present invention will now be described with reference to the accompanying drawings, in which:
FIG. 1 is a front view of a four-cylinder four-stroke internal combustion engine having an ignition system according to the present invention,
FIG. 2 is a view through the cover of the ignition system module on the elements of the ignition system in accordance with the present invention,
FIG. 3 is an enlarged side view of an adapter for attaching a magnet to a cam shaft, and also a sensor module according to the invention,
FIG. 4 is a front view of an adapter for mounting a magnet on a cam shaft, as well as a circuit board of a sensor module according to the invention,
FIG. 5 is a connection diagram of a Hall effect sensor according to the invention,
FIG. 6 is a circuit diagram for connecting sensor and ignition elements for a single-cylinder embodiment according to the invention.

 In the accompanying drawings, the same elements denote the same elements, in particular in FIG. 1 is a front view of an internal combustion engine equipped with a solid state ignition system according to the present invention. The sensor module SM is attached to the TC “synchronization cover” with two screws RS1 and RS2, which pass through the TC cover through two adjustment slots AS1 and AS2, made in the flange of the SM module. The SM module can be turned clockwise or counterclockwise, having previously loosened the screws RS1 and RS2 and applying force to the synchronizing protrusion TT, which is available on the SMC cover of the SM module. As will be shown, the rotation of the SM module leads to an advance of the ignition moment or to its delay. The drawing also shows two modules FM 1.3 and FM 2.4 ignition. More precisely, these are the covers MC1 and MC2 of the ignition modules, which look similar to the usual valve box covers that are attached to the cylinder heads CH1 and CH2. The covers MC1 and MC2, as well as the elements that are under the covers and fastened with them, form the modules FM 1,3 and FM 2,4, the operation of which will be described below with reference to FIG. 2, 5 and 6.

 In FIG. 2 shows an ignition module FM 1.3 according to the present invention, the elements inside are shown by dashed lines. FM module 1.3 contains a circuit board CB1 for a double coil or field coil, two ignition coils 1C1 and 1C3, two sockets PT1 and PT3 for spark plugs, a cover MC1 for the ignition module, and an output terminal ST of the sensor also has wires connecting the elements of the system. For convenience, the image of the wire in FIG. 2 conventionally not shown. The sensor output from the SM module is sent to the ST terminal via a shielded wire (which is not shown). Further, the sensor output signal is supplied from the ST terminal to the circuit board CB1, in which there are two integrated circuits CD1 and CD3, hereinafter referred to as ASIC excitation windings, which enable the low-voltage primary windings of the coils 1C1 and 1C3. The output from circuit board CB1 triggers coils 1C1 and 1C3, which in turn provide high voltage, which is fed through the high-voltage wires to the terminals (not shown) of the two spark plugs. High-voltage wires are attached to the spark plugs using sockets PT1 and PT3. The electrical contact between the wires and the terminals of the candles is provided by a spring device. All the high-voltage elements described above are located under the cover of MC1, which is in contact with the motor design and provides shielding of the radio noise source in accordance with the requirements for electromagnetic compatibility in force in different countries. The aforementioned shielding of the radio interference source cannot be compromised when the FM 1.3 module is securely fixed to the cylinder head (which is not shown). It should also be noted that the FM 2.4 module is similar to the FM 1.3 module and is intended for the other two cylinders of the engine of the present invention.

 In FIG. 3 shows a side view of the adapter for attaching a magnet to the cam shaft CS, as well as the module SM. The SM module mounting plate SB, which combines the four latched Hall effect integrated circuits, as well as the corresponding connections between the elements, as will be described below, are generally indicated by the SMC cover. The advantages of using a Hall effect device compared to other magnetic means designed to determine the angular position of the crankshaft are as follows: (1) minimum block sizes, (2) low cost, (3) minimum number of elements, (4) clear actuation, (5) satisfactory resistance against the influence of surrounding sources.

Latched Hall effect devices have the advantage that the response times can be set using two very small permanent magnets. This is the difference from widespread external devices without a latch and with a stretched output signal. In FIG. 3 shows an adapter MA, in which two miniature permanent magnets N and S are fixed. Magnets N and S are mounted with an offset of 90 ^{° from} each other on the outside of the adapter MA. The poles of the N and S magnets on the outer surface of the MA adapter are different: N is the north magnetic pole, and S is the south magnetic pole (magnet arrows). The adapter MA is mounted on an extension of the camshaft CS, which passes through a sealed hole in the cover TC. As shown in the following drawings, the MA adapter, SB mounting plate, and SMC cover are centered and concentric, providing the necessary clearance during operation between the MA adapter and CB mounting plate.

In FIG. Figure 4 shows a front view of the SB mounting plate, adapter, HA1 - HA4 devices, as well as the corresponding layout, with the N and S magnets offset 90 ^° from each other, and the north (N) pole of one magnet and the south pole (S) of another magnet outward. When the CS camshaft rotates clockwise at a constant speed, any of the mentioned HA1 - HA4 devices will be affected by the magnetic field of magnet N, and then magnet S with short intervals between magnets S and N. HA1 - HA4 devices are located at 90 ^° intervals near the inner SB circuit board edges. All elements have the same circuit, which will be described in detail below with reference to FIG. 5.

 In FIG. Figure 5 schematically shows the elements of one of four identical sensor connection circuits installed on the SB mounting plate, the circuit shown showing a solid-state integrated circuit HA1 working according to the Hall principle with a latch (A3185E), and there is also a resistor R1 with a resistance of 250 Ohms. An adjustable voltage source 5 VS is connected to terminal 1 of the solid state integrated circuit HA1, working on the Hall principle, as well as one side of the resistor R1. Terminal 2 is grounded. The other side of resistor R1 is connected to output HA1 via terminal 3. Output HA1 at terminal 3 is connected to an ignition circuit that is not shown. In this embodiment, the regulated source maintains a voltage of 5 V at terminal 1 of the integrated circuit HA1 of the solid-state device operating according to the Hall principle with a latch, thereby providing a bias voltage on HA1. Resistor R1 is used to maintain voltage at terminal 3 of the solid state integrated Hall circuit with latch HA1 at a high level when this circuit HA1 is in the off state.

 In FIG. 6 is a functional electrical diagram including sensor elements and ignition circuits required for one cylinder, with magnets N and S attached to the adapter. The arrow shows the clockwise direction of rotation. The sensor circuit that has been described with reference to FIG. 5 is fully designated as an SC sensor circuit. Fieldbus 1C ASIC CDI, VB92IZVSP has a design developed by SGS-THOMSON MICROELECTRONICS and contains resistors R2 and R3, a Zener diode D1, a diode D2, a Trillington power transistor Q1 with vertical current, and an integrated control circuit VD1. The ignition coil 1C1 contains the primary winding WPI and the secondary winding WSI, there are capacitors C1 and C2, as well as a transient voltage damper TVSI. The voltage source VS is connected to one side of the primary winding WPI, the other side of which is grounded through the ASIC CDI.

 It will be understood that the operating procedure of the ignition system of the present invention below in accordance with FIG. 6 is applicable to other sensor circuits and ignition circuits. Since the ignition system is inherently repetitive in nature, it is assumed in the description below that the starting point is arbitrary. In this case, the MA adapter rotates clockwise, as shown, and the magnet N is located at the solid-state integrated circuit HA1, which works according to the Hall principle with a latch. The magnet N field causes the integrated circuit HA1 of the solid state latching Hall effect sensor to open at terminal 3 from ground. In this case, 5 V is supplied to the output of terminal 3. A voltage of 5 V is applied to the excitation winding of the ASIC CDI, as a result of which the transistor Q1 is turned off, and the lower side of the WPI coil is grounded. As a result, current flows through the WPI winding, and a magnetic field forms in coil 1C1. This field can increase during the time necessary to activate the HA1 device due to the presence of an oppositely directed magnetic field. This difference is characteristic of Hall devices with a latch in comparison with Hall devices without a latch, in which the operating state is not maintained in the absence of an excitation field in the device.

 When the magnet S passes near the integrated circuit HA1 of the latched solid-state Hall sensor, the output HA1 at terminal 3 is grounded. The transistor Q1 is turned on. When transistor Q1 is open, the current in WPI is interrupted, and the field induced in coil 1C1 disappears. High voltage is induced in the secondary of WP2, which is grounded through the spark plug. The resulting electric arc between the electrodes of the candle ignites the charge of the combustible mixture in the cylinder. Diodes D1 and D2 are designed to protect the circuit. Diode D1 stabilizes the collector voltage, diode D2 smooths the reverse voltage peaks that occur when the field disappears in the coil, and UD1 amplifies, regulates and limits the current in the coil. Coil 1C1 is not connected to a power source until the magnet N passes through a given point, after which the cycle repeats, as described above. TVSI transient voltage dampers, as well as C1 and C2 capacitors, are optional; they are used to suppress noise in the system.

 In a second embodiment of the invention (which is not shown), transistors acting on the field and triggered by high-speed exciters are used to turn on the low-voltage primary windings. It should be noted that, although the preferred embodiment of the invention provides for the use of ASIC coil starters discussed above, there are many systems that provide low voltage primary windings.

It is understood that, although the magnets described above are located at an angle of 90 ^° relative to each other in accordance with the invention, the circumferential distance between the magnets N and S determines the response delay time, which may be less than that obtained in the system described above. In addition, the passage of magnet S and the ignition of the charge of a combustible mixture in a given cylinder after a short time interval after this passage generally correspond to the moment when the piston reaches top dead center or the moment with a given ignition advance until the piston reaches top dead center or before the start of the stroke. Therefore, the angular distance between the sensors must be the same regardless of the number of cylinders in a particular engine in which the system described above is applied. It is understood that by turning the SM module relative to the angular position of the cam shaft, the moment of occurrence of a spark in all cylinders can equally be done sooner or later.

 A contactless ignition system operating without a distributor, which has been described above, has several advantages. Using devices operating according to the Hall principle with a latch, it is possible to simplify the device of the sensor, as well as the method of controlling the delay of operation. By determining the angular position of the cam shaft, a spark is formed in each cylinder only once during the working cycle, and not twice, thereby freeing this system from excessive load. It is essential that this system contains only four main components: an adapter made of iron-free material with two permanent magnets, mounted on a cam shaft that passes through an oil seal in the ignition timing control cover, a sensor module, two identical ignition modules. Such a modular design allows you to quickly dismantle and replace elements, which reduces the complexity and cost of repair work. In addition, since all components with high voltage are shielded from the ignition module cover in terms of eliminating radio frequency and electromagnetic interference, the requirements for individual shielding of many components are eliminated, and the wiring of this system is also simplified. Also, since the wiring is well protected on the outside, and the ignition modules and sensors have very simple and continuous covers, the whole engine can simply be cleaned or washed outside without harmful effects on the operation of the ignition system. Although the present invention has been described by way of example of its preferred embodiment with reference to the accompanying drawings, it is understood that various changes and modifications are possible within its scope, as described in the attached claims.

Claims (17)

 1. An electronic ignition system containing a means for periodically generating magnetic fields of opposite polarity, means for determining the first and second polarity of the generated magnetic fields, including several sensors working according to the Hall principle with a latch, characterized in that in each of sensors operating according to the Hall principle, there is a means to increase the potential of the accumulated output signal in response to the presence of the first polarity non-generated magnetic fields, means for generating an accumulated output signal in response to the presence of a second polarity of said generated magnetic fields and means for generating a high voltage ignition signal in response to the issued output signal.  2. The electronic ignition system according to claim 1, characterized in that the means for periodically generating magnetic fields of opposite polarity contains a non-magnetic rotating element with magnetic elements of opposite polarity fixed to it and located at a distance from each other.  3. The electronic ignition system according to claim 2, characterized in that the non-magnetic rotating element is a disk, and magnetic elements located at a distance from each other are permanent magnets whose poles of opposite polarity are directed outward relative to the periphery of the disk.  4. The electronic ignition system according to claim 3, characterized in that the rotating element is mounted on the cam shaft of the internal combustion engine.  5. The electronic ignition system according to claim 4, characterized in that the cam shaft passes through the seal in the cover of the ignition timing control assembly in the internal combustion engine.  6. The electronic ignition system according to claim 3, characterized in that the sensors operating according to the Hall principle with a latch are spaced circumferentially relative to each other around the axis of rotation of the rotating element and are located in a plane adjacent to and parallel to the rotating element.  7. The electronic ignition system according to claim 1, characterized in that the means for increasing the potential of the accumulated output signal includes an electronic amplifier.  8. A shielding system for radio-frequency and electromagnetic interference in an electronic ignition device, comprising means for generating high-voltage ignition signals, a control circuit for the means for generating ignition signals and a shielding device for protecting the means for generating ignition signals, and a circuit for radio-frequency and electromagnetic interference, characterized in that the generation of the ignition signals, as well as the circuit are jointly mounted inside the cavity, limited by the shielding means, which see mounted on engine design.  9. The system of claim 8, wherein the control circuit includes an electronic amplifier and an electronic switching device, and the means for generating an ignition signal comprises an ignition coil.  10. The system according to claim 9, characterized in that the electronic switching device is a bipolar transistor.  11. The system according to claim 9, characterized in that the electronic switching device is a field effect transistor.  12. The system according to claim 9, characterized in that the electronic amplifier is an integrated control circuit.  13. The system of claim 8, characterized in that the spark plug is used as a means of generating a high voltage ignition signal.  14. The system of claim 8, characterized in that the shielding means includes a single metal cover that covers the means for generating the ignition signal, as well as the control circuit, which are located in the cavity under it.  15. The system of claim 14, wherein the shielding means includes a cylinder head cover.  16. An electronic ignition system containing a disk of iron-free material with two permanent magnets of opposite polarity mounted on it, mounted on the cam shaft of an internal combustion engine, several sensors working according to the Hall principle with a latch, each of which is designed to determine the polarity of the permanent magnets during rotation of the rotating disk, and the sensors are spaced in a circumferential direction relative to each other around the axis of rotation of the disk and placed in a plane, parallel to the disk and adjacent to it, a means of generating high-voltage ignition signals issued to at least one spark plug in an internal combustion engine in response to detection by sensors operating on the basis of the Hall principle of polarity of permanent magnets, a means of shielding radio frequency and electromagnetic interference arising from at least from the operation of the means generating the high-voltage ignition signals, characterized in that the shielding means is installed on the internal combustion engine anija and ignition signal generating means is mounted in the cavity completely shielding means.  17. The electronic ignition system according to clause 16, characterized in that it is configured to interact with a multi-cylinder internal combustion engine.

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