RU2221298C2 - Bar ignition coil - Google Patents

Abstract

FIELD: engine manufacture; internal combustion engines. SUBSTANCE: ignition coil used for ignition systems and provided with device for measuring ion current passing through spark plug electrodes has laminated magnetic core one of whose central layers is built of several longitudinal plates, primary and secondary windings, low-voltage connector, and capacitor whose symmetry axis is parallel to that of core. One of capacitor plates is connected to low-voltage connector contact through pilot strip disposed between plates of mentioned central layer of magnetic core. EFFECT: enhanced manufacturability and reliability, reduced cost of coil. 5 cl, 7 dwg

Description

 The invention relates to engine building and can be used in the design of the core coil of the ignition system of an internal combustion engine (hereinafter - ICE), equipped with a device for measuring ion current flowing through the electrodes of the spark plug.

 Known (see, for example, patents RU 2117820 C1, IPC 6 F 02 P 3/02, publ. 08.20.98, RU 2123132 C1, IPC 6 F 02 P 3/02, publ. 10.12.98) individual ignition coils made in the form of a rod (hereinafter - rod ignition coils).

 The shape and dimensions of the rod ignition coils are due to the need to place the coils in the deep narrow candle channels of the multi-channel ICE.

 Known technological design of a magnetic core for a rod ignition coil, see application WO 99/16092, MPK 6 H 01 F 41/02, publ. 04/01/99, the Magnetic core, the shape of which is close to cylindrical, is made lined, that is, assembled in the form of a package of rectangular plates. Each of the plates is provided with ridges and depressions, which allow the plates to be joined into a packet by compression.

 From patent RU 2103543 C2, IPC 6 F 02 P 17/00. publ. 01/27/98, bull. 3, a device is known for measuring the ion current flowing through the electrodes of a spark plug, including a passage capacitor and a diode.

 A rod ignition coil is known from patent RU 2152534 C1, IPC 7 F 02 P 3/02. . The coil is equipped with a device for measuring ion current, including a diode and a capacitor, one of the plates of which is connected to the primary connector.

 The design flaws are increased requirements for the insulation of the capacitor and the magnetic core, leading to the complication and cost of the ignition coil. The disadvantages are due to the location of the capacitor near the low voltage connector.

 For the prototype of the claimed invention taken rod ignition coil (patent RU 2165543 C2, IPC 7 F 02 P 3/02, publ. 04/20/2001, bull. 11). The coil contains a charged magnetic core, primary and secondary windings located around the core, a magnetic screen with a slot covering the core with windings, as well as a low-voltage connector, a high-voltage connector and an ion current measuring device, including a diode and capacitor located near the high-voltage connector. One of the capacitor leads is connected to the contact of the low-voltage connector by a signal bus located in the slot of the magnetic screen.

 The advantage of the prototype coil is the successful location of the capacitor in the coil. When placing a capacitor near a high-voltage connector, the requirements for insulation of the capacitor are reduced, thereby reducing the cost of manufacturing a coil.

 The disadvantage of the prototype is the high complexity of the manufacture of the coil, due to the use of manual labor when laying the signal bus in the slot of the magnetic screen.

 The task of the invention is the creation of technological. reliable and cheap ignition coil equipped with a device for measuring ion current.

 This problem is solved in the ignition rod coil, which includes a charged magnetic core, windings located around the core, a low-voltage connector, a high-voltage connector, and a diode and capacitor located near the high-voltage connector, the axis of symmetry of the capacitor parallel to the axis of symmetry of the core, and one of capacitor plates connected to the contact of the low voltage connector signal bus.

 The problem is solved in that at least one of the central layers of the magnetic core is made of several longitudinal plates, and the signal bus is placed between the plates of the said central layer of the magnetic core. In this case, the central layer can be made of two plates, the sizes of the plates of the central layer of the magnetic core can coincide with the sizes of the plates of the peripheral layers of the magnetic core, the end of the splint adjacent to the capacitor can be provided with a pin contact, and at least one of the plates of the capacitor can be equipped with a socket contact.

 Figure 1 shows the ignition coil assembly.

 Figure 2 shows the node of the magnetic core.

 Figure 3 shows a schematic diagram of an ignition coil.

 Figure 4 shows a plot of the current 11 in the primary winding of the ignition coil.

 In FIG. 5 shows a plot of voltage U2 in the secondary winding of an ignition coil in front of a diode VD.

 In FIG. 6 shows a plot of voltage Uc in the secondary winding of the ignition coil on capacitor C.

 In FIG. 7 shows a plot of the voltage Ur on a current-measuring resistor R.

 The invention can be implemented in the design of a rod ignition coil (see Fig. 1), which includes at least a housing 1 and a magnetic core 2, a primary 3 and a secondary 4 windings, a low voltage connector 5, a high voltage connector 6, located in the housing capacitor 7, signal bus 8 and diode 9.

 To implement the invention in the design, the following changes are made.

 In a preferred embodiment of the invention (see figure 1), the capacitor 7 is made in the form of a cylinder, with at least the inner lining of the capacitor is provided with a socket contact 10.

 Note that the outer lining of the capacitor 7 can also be provided with a female contact (not shown).

 The central layer of the core 2 (see figure 2) is made of several longitudinal plates 11, 12. In the best embodiment, there may be two such plates. Moreover, to increase manufacturability and reduce the cost of manufacturing a coil, plates 11, 12 of the central layer can use plates from which the peripheral layers of the core 2 are assembled.

 The plates 11, 12 of the core 2 are provided with fastening means made in the form of depressions and ridges (not shown).

 The core 2 is obtained by combining two identical halves of the core, appropriately oriented with their ridges and troughs, one of which includes a plate 11 and the other plate 12. Between the halves of the core (between the central plates 11, 12) a signal bus 8 of electrically conductive material is laid. When the halves of the core 2 are compressed with each other, the crests of one half enter the troughs of the other half, forming a rigid mechanical connection. The result is a magnetic core 2 with a signal bus 8 inside.

 The signal bus 8 can be inserted inside the magnetic core 2 also after crimping the halves into the core.

 The end 13 of the signal bus 8, intended for connection with the output of the capacitor 7, may be provided with a pin contact 14.

 The connection of the inner lining of the capacitor 7 with the signal bus 8 is preferably carried out by inserting the pin contact 14 into the socket contact 10 of the capacitor. This eliminates the need for welding or soldering in hard-to-reach places and reduces labor costs when assembling the ignition coil.

 The outer lining of the capacitor 7 is connected through a diode 9 with the output of the secondary winding 4.

 The second end of the signal bus 8 and the conclusions of the windings 3, 4 of the ignition coil are crimped or welded with the corresponding contacts of the low-voltage connector 5.

 The operation of the ignition coil, the circuit diagram of which is presented in FIG. 3, occurs in two consecutive modes: the mode of formation of a spark discharge and the subsequent diagnostic mode.

Referring to FIG. 3 schematic diagram of the ignition coil contains the following notation:
L is the inductance of the primary winding;
M is the magnetic core;
VD - diode;
R is a current measuring resistor;
C is a capacitor
SP - spark plug.

 The formation of a spark discharge occurs in the traditional way.

When current flows through the primary winding L of the ignition coil, a magnetic flux appears in its magnetic core M, and accordingly, the energy W, which is determined by the formula, is accumulated in the magnetic field of the ignition coil:
W = _^1/2 LI ²
where I is the amplitude of the accumulation current in the primary winding; L is the inductance of the primary winding.

 The interruption of the current in the primary winding when it is turned off causes a rapid decrease in the magnetic flux to zero, which, in turn, by the law of induction causes the appearance of an EMF located in the primary and secondary windings of the coil, in proportion to the number of turns.

 The high voltage U2, see FIG. 5, developed in the secondary winding, enters the capacitor C through the diode VD, as a result of which the capacitor charges.

 When the voltage across the capacitor reaches Ub, see FIG. 6 (the breakdown voltage of the spark gap of the spark plug installed and the combustion chamber of the ICE is not shown in the figure), an electric breakdown of the spark gap of the spark plug SP occurs and the voltage across the spark gap decreases sharply ( see Fig. 5) to the voltage Us, the burning of a glow discharge (spark discharge occurs).

 A spark discharge causes ignition of the air-fuel mixture in the combustion chamber of the internal combustion engine and subsequent working stroke.

 After the energy stored in the magnetic field has been used up to maintain a glow discharge, the spark discharge stops and the coil switches to diagnostic mode, in which resonant voltage fluctuations are excited in the secondary coil. The resonance vibrations are excited by periodically passing the excitation current through the primary winding of the ignition coil with a frequency close to the natural frequency of the secondary windings. The magnitude of the excitation current, see figure 4, is ten times less than the accumulation current (0.2 A and 10 A, respectively).

 The voltage of the resonant oscillations produces a capacitor charge to the amplitude value Ua, see FIG. 5, to obtain a positive voltage applied to the spark gap of the spark plug.

 Under the action of the applied positive voltage, the ion current i formed by the combustion products of the air-fuel mixture begins to flow through the spark gap of the spark plug. In this case, the ion current i flows from one lining of the capacitor C to another through the spark gap of the spark plug, causing the discharge of the capacitor C to some residual value Ur, see Fig. 6, which depends on the value of the ion current i. The magnitude of the ion current i is determined by the parameters of the medium in the spark gap of the spark plug placed in the combustion chamber of the internal combustion engine, which, in turn, is determined by the operating conditions of the internal combustion engine. Each subsequent resonant oscillation causes a capacitor to be recharged C from the residual voltage value Ur to the amplitude value Ua of the resonant oscillations, see FIG. 5. The process of exciting resonant oscillations continues until the end of the combustion cycle in the combustion chamber.

 By measuring the current to the charge, see Fig. 7, of the capacitor, for example, using a current-measuring resistor R connected in series to the output of the capacitor C, one can judge the amount of ion current i flowing in the spark gap of the spark plug SP, see Fig. 6 , since it follows from the law of conservation of charge that during the pulse repetition period before the charge, the current integral to the charge is equal to the ion current integral for the same period.

 The magnitude of the ion current depends on such parameters as the pressure in the combustion chamber, temperature, fuel composition, air / fuel ratio of the initial air-fuel mixture, etc.

 By analyzing the ion current, it is possible to obtain information about all these parameters, which can be used both for diagnostics and for controlling the internal combustion engine.

Claims (5)

1. The rod ignition coil, which includes a charged magnetic core, windings located around the core, a low voltage connector, a high voltage connector and a capacitor, the axis of symmetry of which is parallel to the axis of symmetry of the core, and one of the plates is connected to the contact of the low voltage connector by a signal bus, characterized in that that at least one of the central layers of the magnetic core is made of several longitudinal plates, and the signal bus is placed between the plates of the said central layer. 2. The rod ignition coil according to claim 1, characterized in that the central layer is made of two plates. 3. The rod ignition coil according to one of the preceding paragraphs, characterized in that the dimensions of the plates of the central layer of the magnetic core coincide with the dimensions of the plates of the peripheral layers of the magnetic core. 4. The rod ignition coil according to one of the preceding paragraphs, characterized in that the end of the bar adjacent to the capacitor is provided with a pin contact. 5. The rod ignition coil according to one of the preceding paragraphs, characterized in that at least one of the plates of the capacitor is provided with a socket contact.

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