LT5465B - A coaxial sparking cable - Google Patents

Abstract

The invention relates to electrotechnics, specifically to sparking cables of plugs, which can be used in internal-combustion engines. Coaxial sparking cable comprises internal conductor, insulation, cable-shaped external conductor, which is rolled in longitudinal direction. Loops of cable are insulated one from another. A cable can be flatted. Internal conductor can be cable, which is rolled jointly on magnetic core. Cable loops of internal conductor can be insulated one from another. Cable of internal conductor can be flatted.

Description

The invention relates to electrical engineering, in particular to spark plug cables used in internal combustion engines.

For a long time, the engines used insulated copper conductor ignition cables. The impedance of the current conductor was practically zero (R = 0). This avoided electricity losses, but the level of radio interference was high because the cable acted as the transmitter antenna.

The installation of electronic devices in engines and vehicles has created a problem of electromagnetic compatibility. Various ignition cables with R = 12-17 kQ / m are known. The current conductors are made of various insulating materials with carbon additive. The level of radio interference has decreased significantly. However, such cables significantly reduce the spark current.

Known ignition cables (for example, U.S. Patent No. 5,576,614) in which the current conductor is made of a thin wire having a high relative impedance wound on a magnetic core. The resistance of the cable has decreased to R = 1-5 kQ / m and is less “noisy” due to distributed inductance. Energy losses have decreased and cable prices have risen.

Known coaxial ignition cables are described, for example, in International Patent Application PCT / US98 / 05360. Because R = 0 and distributed capacitance C, they not only reduce spark energy, but also increase its power. However, the coaxial cable emits powerful electromagnetic rays in the form of extinguishing radio pulses because the discharge current of the cable travels linearly t along the axis of the cable.

The closest to the device described is, by its technical nature, a coaxial cable (patent SU 1602250) having an inner conductor, an insulation, an outer conductor and a sheath. In addition, the outer conductor is made of flattened wire covered with solder and wound lengthwise, with the solder at the edges.

It is an object of the present invention to provide an ignition cable that combines the advantages of all known solutions without the disadvantages. That is, the cable must be free of power loss and radio interference and, at the same time, must increase the spark power.

This object is achieved by the coaxial ignition cable having an inner conductor, an insulation, an outer conductor in the form of a longitudinally wound conductor, and a sheath which is insulated from one another. The cord may be flattened. In addition, the inner conductor may be in the form of a wire wrapped around a magnetic core. The conductor wires of the inner conductor may be insulated from one another. The inner conductor wire may be flattened.

The invention will now be described with reference to Figure 1, which is a cross-sectional view of a coaxial ignition cable.

The cable has an inner conductor 1, an insulator 2, an outer conductor 3 in the form of a winding wire with insulated windings, and a sheath 4. The outer conductor 3 forms a distributed capacitance C relative to the inner conductor 1. The insulator 2 provides the electrical strength of the cable and determines the size of the distributed capacitance C. Sheath 4 gives the cable mechanical strength. Magnetic core 6 increases the inductance distributed by both conductors and reduces radio interference. Kevlar thread 7 increases the axial strength of the cable.

The cable works as follows: Internal conductor resistance R = 0, one end of which is connected to a high voltage source and the other to the spark plug. The resistance of the outer conductor 3 is R = 0, it is connected at one end to the mass (housing).

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The cable capacitance C stores energy E = -, where U is the breakdown voltage. The greatest radio interference occurs when the spark plug gap is pierced. The current of the external conductor 3 flows in a spiral, which, compared to conventional coaxial cables, increases the discharge time and significantly reduces the level of radio interference. By making the inner conductor 1 longitudinally wound on a magnetic core 6 in the form of a wire, we obtain a kind of transformer with distributed capacitors and inductances. In it, the fields emitted by the primary and secondary windings can additionally compensate for each other.

In this way, this cable accomplishes the objectives of the invention:

- minimum electricity losses;

- Minimal radio interference;

- Maximum increase in spark strength.

In addition, the capacitance discharge of the cable is in the form of a quenching radio pulse but has a lower current amplitude and a lower frequency than conventional coaxial cables, which reduces the electrocorrosion of the spark plug electrodes.

It should also be noted that the production of this cable is relatively simple and increases operational safety.

Claims (5)

DEFINITION OF INVENTION 1. A coaxial high-voltage ignition cable having an inner conductor, an insulator, an outer conductor in the form of a coiled conductor and a sheath, characterized in that the conductor strands are insulated from one another. 2. The cable of claim 1, wherein the cable is flattened. 3. Cable according to claim 1 or 2, characterized in that the inner conductor is in the form of a wire wrapped longitudinally on a magnetic core. 4. A cable as claimed in claim 3, wherein the wires of the inner conductor are insulated from one another. 5. The cable of claim 3 or 4, wherein the inner conductor wire is flattened.