JPH04134182A - Spark plug for internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a spark plug for an internal combustion engine, and particularly to a spark plug for an internal combustion engine that has an ionic current detection electrode in addition to a high voltage electrode for detecting an ionic current. It is related to.

[Prior Art] FIG. 3 is a configuration diagram showing a conventional spark plug for an internal combustion engine. In the figure, (1) is a center electrode, (2) is an insulator that covers this center electrode (1), (3) is a housing that covers a part of this insulator (2), and (4) is this housing (3). A ground electrode is attached and provided facing the center electrode (1), and the ground electrode (4) and the center electrode (1) constitute a high voltage electrode. (5) is a rod-shaped ion current detection device that is installed in the insulator (2) at a predetermined distance from the center electrode (1), and is used to detect the ion current generated by the combustion of the air-fuel mixture in the cylinder between the internal combustion engines. electrode, (6) is the lead wire connected to this electrode (5), (7) is this lead wire (
6) is the attached external connection connector, (8) is the ion current detection unit connected to this external connection connector (7), and (9) is the ion current installed in the ion current detection unit (8). (10) is a signal processing section provided in the ion current detection unit (8);
1) is the output terminal of the ion current detection unit (8);
2) is an ionic current path, (13) is a conductive terminal attached to one end of the center electrode (1), (14) is a power distributor or ignition coil connected to terminal (13),
(15) is the engine to which the housing (3) is attached, and (16) is the engine combustion chamber.

Next, the operation of the conventional spark plug for an internal combustion engine shown in FIG. 3 will be explained. When the power transistor (not shown) is controlled and turned off by the fuel injection timing/ignition timing control unit (not shown) in synchronization with the rotation of the internal combustion engine, a back electromotive force is generated on the primary side of the ignition coil (14). This negative high voltage is supplied to the center electrode (1), and a discharge occurs between the center electrode (1) and the ground electrode (4), which causes the spark plug to ignite. When the air-fuel mixture in the engine combustion chamber (16) is ignited by the ignition plug, an ion current is generated, which is detected by the ion current detection electrode (5), and the electrode ( 5) is negatively biased, the ion current path (
12), the signal is supplied to the signal processing unit (10) for processing, and then supplied to a computer unit (not shown) or the like.

[Problems to be Solved by the Invention] Since the conventional spark plug for an internal combustion engine is configured as described above, the surface area of the ionic current detection electrode (5) exposed in the engine combustion chamber (16) is small. However, there was a problem in that the detection performance was poor because the contact area with the combustion gas was small.

This invention was made to solve the above-mentioned problems, and an object thereof is to obtain a spark plug for an internal combustion engine that has excellent detection performance.

[Means for Solving the Problems] A spark plug for an internal combustion engine according to the present invention includes an ion current detection electrode with a large surface area provided separately from a high voltage electrode in order to detect the flow of ions, and the electrodes are arranged in a grid pattern. This is what I did.

[Function] In the present invention, the electrode for detecting liquid ions is formed into a lattice pattern to increase its surface area, thereby increasing the contact area with combustion gas and improving the detection performance.

[Example 1] An example of the present invention will be described below with reference to the drawings. 1st
The figure is a configuration diagram showing one embodiment of the present invention, and (1) to
(4), (6) to (16) are the same as described above.

In this example, the rod-shaped ion current detection electrode (5
), for example, a cylindrical ion current detection electrode (5A) with a large surface area is used. As shown in an enlarged view in FIG. 2, this ion current detection electrode (5A) is provided with a plurality of grid-like holes (5A) arranged around a predetermined position, for example, at the lower end.
), which reduces the flow resistance of combustion gas and prevents the combustion output from decreasing.

Next, the operation of the embodiment of the present invention shown in FIG. 1 will be explained. Fuel injection timing is synchronized with the rotation of the internal combustion engine.
When the power transistor (not shown) is controlled to turn off by the ignition timing control unit (not shown),
A back electromotive force is generated on the primary side of the ignition coil (14), and this negative high voltage is supplied to the center electrode (1).
) and the ground electrode (4), which causes the spark plug to ignite. When the air-fuel mixture in the engine combustion chamber (16) is ignited by the spark plug, an ion current is generated, which is detected by the ion current detection electrode (5A), and the electrode ( 5
A) is negatively biased, so the ion current path (12
) is supplied to a signal processing unit (10) for processing, and then supplied to a computer unit (not shown) or the like.

In this way, in this example, a grid-like cylindrical electrode is used as the ion current detection electrode, so the surface area is large and the contact area with the combustion gas is widened, which improves the detection performance and maintains a constant combustion output. It can be secured.

In the above embodiment, a cylindrical electrode with a large surface area is used as the ionic current detection electrode, but other shapes such as a flat plate type may be used as long as the surface area is large.

[Effects of the Invention] As described above, according to the present invention, an ion current detection electrode with a large surface area is provided separately from a high voltage electrode to detect an ion current, and the electrode is shaped like a grid. This has the effect of increasing the contact area with combustion gas, improving detection performance, and providing a spark plug for an internal combustion engine that can ensure a constant combustion output.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a perspective view showing essential parts of the present invention, and FIG. 3 is a block diagram showing a conventional spark plug for an internal combustion engine. In the figure, (1) is the center electrode, (4) is the ground electrode, (
5A) is an electrode for detecting ionic current. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A spark plug for an internal combustion engine, characterized in that an ion current detection electrode with a large surface area is provided separately from a high voltage electrode to detect an ion current, and the electrode is shaped like a grid.