RU2243406C2 - Fuel mixture electric spark ignition device - Google Patents

Abstract

FIELD: heat power engineering, mechanical engineering, electronics and circuit engineering.

SUBSTANCE: invention is aimed at creating electric spark ignition device with universal circuit providing unlimited increase of power of periodical spark discharge and increase of efficiency of use of energy accumulated between discharge. Proposed device includes the following elements series-connected to current source: switch, primary winding of step-up pulse transformer and capacitor. Switch is installed in parallel with primary winding and capacitor. Capacitor-accumulator, connected through switch with current source or separate charging device, is connected in series with secondary winding of step-up transformer.

EFFECT: simplified design, reduced mass and overall dimensions.

2 dwg

Description

The present invention relates to the field of power engineering, engine manufacturing, as well as electronics in the field of circuitry.

A device is known for electric spark ignition of a fuel mixture (a mixture of gasoline, natural gas or other types of liquid or gaseous fuel with air) in internal combustion engines, including a direct current source, an ignition coil, which is a step-up transformer, a current chopper (key) and a distributor (see , for example, A.G. Khodasevich, T.I. Khodasevich “Handbook for the installation and repair of electronic devices of automobiles. Issue 1. Electronic ignition systems”, M., Publishing house “ANTEL-KOM”, 2001, pp. 14-16, Fig. 2.1). A spark igniting the mixture is formed in the spark gap (spark gap) of the spark plugs equipped with two electrodes. Featuring sufficient reliability, which is why this device is widely used in the automotive industry, the latter also has a number of significant drawbacks. These include, first of all, the transformation of all energy for the formation of a spark to a voltage that can break through the spark gap. This results in a decrease in efficiency, since in the ionized gap, the conductivity increases significantly. In this regard, most of the energy stored in the coil is lost in the internal resistance of the spark source. For this reason, in order to obtain a high-energy spark, it is necessary to irregularly increase the size and mass of the ignition coil or to generate a series of consecutive discharges into the gap, which after the first spark only slightly accelerate fuel combustion and additionally overheat the coil. Another disadvantage of this type of device is the increased energy of the emitted radio noise, the fight against which further reduces the energy of the spark, as well as a noticeable decrease in the power of the spark when the coil is heated.

In modern ignition devices, the interrupter contacts are replaced by contactless systems. At the same time, the basic principle of spark formation due to magnetic energy stored by the ignition coil in pauses between discharge pulses is retained (see, for example, the above source, page 33, Fig. 5.1). The disadvantages of these devices are the same as above.

Also known are spark spark ignition devices, referred to as capacitor. They are distinguished by increased spark energy due to a capacitor that accumulates charge in the pauses between pulses and discharged by a transistor or thyristor key into the primary winding of the ignition coil. The circuitry of capacitor devices is very diverse (see, for example, the above source, p. 83, Fig. 6.6 and 6.7; p. 89, Fig. 6.14) while maintaining the main principle of transforming all stored energy to a voltage of 20-30 kV, which can break through spark gap of a candle with high compression in the engine cylinders. The disadvantages of condenser devices also include the inability to achieve high energy efficiency of the combusted fuel due to the insufficient burning rate and the currently required reduction in toxicity of exhaust gases. In addition, the use of currently existing capacitor devices for ignition of high-power energy burners (gas, oil, etc.) is possible only with the use of low-power intermediate ignition burners, which complicates their design. Direct ignition of powerful burners requires an increase in spark energy by hundreds and thousands of times, which is unattainable in devices of the type described above. The same applies to the launch of rocket systems.

Closest to the present invention is a capacitor ignition device comprising a key connected in series to a current source, a primary winding of a step-up pulse transformer and a capacitor. In parallel with the primary winding and the capacitor, a key is also installed. Electrodes of the spark gap are connected to the secondary winding of the step-up transformer (see, for example, the source indicated above, page 30, Fig. 4.4). The inherent disadvantages of this device are fully consistent with those for the above capacitor devices for spark ignition of the fuel mixture.

The objective of the present invention is to provide a device for electric spark ignition of a fuel mixture with a universal circuit that allows you to unlimitedly increase the power of a periodic spark discharge.

The technical result of the invention is to increase the efficiency the use of energy accumulated in pauses between discharges while simplifying the design of the device, in reducing its mass and dimensions, in increasing the efficiency internal combustion engines and improving their environmental performance, in reducing the radiation power of radio interference, as well as in simplifying the design of burner devices.

The specified technical result is achieved due to the fact that in the device for electric spark ignition of the fuel mixture, including a key connected in series to a current source, a primary winding of a step-up pulse transformer and a capacitor installed in parallel with the primary winding and a capacitor, a key and spark gap electrodes connected to the secondary winding of a step-up transformer, a capacitor-drive is connected in series with the secondary winding, connected through a key to a current source or nym charger.

The essence of the invention is as follows.

In the prototype, all the energy stored in the capacitor is simultaneously used to ionize the spark gap and form a spark. When the spark gap is ionized, its resistance is significantly reduced, and most of the energy is lost in the internal resistance of the device. In addition, the current in the spark gap is less than in the primary winding of the transformer, as many times as the number of turns of the secondary winding of the transformer is greater than the number of turns of the primary winding. The current strength in the spark gap in internal combustion engines is thus less than in the primary winding, approximately 100 times.

The desired increase in spark energy can be achieved by direct discharge (not through a transformer) of the energy stored in the capacitor into the ionized spark gap. The use of a direct discharge in the spark gap is known through the use of a third ionizing electrode, for example, in devices forming a flash. However, the use of an ionizing electrode is far from always permissible, especially when using a high-power spark. When operating internal combustion engines, a third ionizing electrode is not used, which is probably due to the complexity of the design of the plug and the device itself due to the need to use additional conductors and high temperatures in the cylinders. But even if it would be possible to use an ionizing electrode, the appearance of additional problems is obvious. At a high frequency of direct discharge cycles of the capacitor into the spark gap, it is necessary to soften the discharge mode. Softening can be achieved by increasing the time of the actual discharge. Without the specified mitigation, i.e. with a hard discharge, the capacitor quickly breaks down, and therefore the operation of the entire device becomes unreliable. In the present invention, a direct discharge was used to form a spark with the corresponding solution to the problem of its softening with the exception of the third ionizing electrode. Thus, the transformer combines ionizing and power functions. Since the energy of the emitted radio noise depends on the voltage in the discharge circuits, the use of a direct capacitor discharge at a voltage two orders of magnitude lower than with existing ignition devices reduces the radio noise to a level that does not require special measures to combat them.

A device that implements the present invention is presented in figure 1.

A key 2, a primary winding 3 of a step-up pulse transformer 4 and a capacitor 5 are connected to a current source 1. Parallel to the primary winding 3 of a transformer 4 and a capacitor 5, a key 6 is installed. Electrodes 8 and 9 of the spark gap 10 are connected to the secondary winding 7 of the transformer 4.

In series with the secondary winding 7 of the transformer 4 is connected to the capacitor-drive 11. The capacitor-drive 11 is connected to the current source 1 through the key 12 (this option provides for the presence of one current source).

Figure 2 shows a device having a separate charger 13 (all other positions of figure 2 coincide in names and numbers with the positions of figure 1), to which a capacitor-drive 11 is connected via a key.

The device for spark ignition of the fuel mixture of the present invention operates as follows. The operation of the device is essentially cyclical in three phases in each cycle. Consider the operation of the device depicted in figure 1. In the first phase, the keys 2 and 12 are closed. In this case, the capacitors 5 and 11 are charged to the full voltage of the source 1. In the second phase, the keys 2 and 12 are opened. In the third phase, the key is closed 6. The capacitor 5 is discharged through the key 6 and the primary winding 3 of the step-up transformer 4. In accordance with the transformation coefficient, a high voltage pulse is induced in the secondary winding 7 of the transformer 4, which can pierce the spark gap 10 between the electrodes 8 and 9. A spark has arisen ionizes the spark gap 10, creating a circuit for the discharge of the capacitor-drive 11 through the secondary winding of the transformer.

There is a discharge of the capacitor-drive 11 into the spark gap 10. The inductance of the secondary winding 7 of the transformer 4 lengthens the discharge time of the capacitor-drive 11, providing a soft discharge mode.

The operation of the device corresponding to figure 2, also passes. The only difference is that the capacitor 11 is charged by a separate charger 13.

As keys 2 and 12 with a DC source, thyristors, transistors, relay contacts can be used. With an AC source, diodes are used as keys 2 and 12. As a key 6, a thyristor, transistor, relay contacts or manual switch contacts can be used.

Since the discharge of the storage capacitor creates a constant component of the magnetic flux in the core in the transformer, the latter must have a gap that accelerates the demagnetization of the core during the pause between discharge cycles. The volume of the transformer core must correspond to the discharge power, depending on the capacitance of the capacitor 11, the voltage across it and the frequency of the charge-discharge periods. The proposed device allows receiving discharges with a power of tens of kW at an average power of units of kW and at a discharge cycle frequency of tens of Hz, which is necessary when igniting powerful energy burners and starting rocket engines in short-term mode, as well as when using electrohydraulic shock in installations continuous mode. In internal combustion engines with continuous operation, the maximum power of the proposed device is tens of watts.

Claims (1)

A device for electric spark ignition of a fuel mixture, comprising a key connected in series to a current source, a primary winding of a step-up pulse transformer and a capacitor, a key installed parallel to the primary winding and a capacitor, and spark gap electrodes connected to a secondary winding of a step-up transformer, characterized in that a capacitor is connected in series with the secondary winding - a drive connected via a key to a current source or a separate charger.

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