JPH02191873A - Ignition method for internal combustion engine - Google Patents

Abstract

PURPOSE:To enable combustion efficiency to be improved by generating a direct and long period spark discharge so as to perform ignition in the upper surface of a piston from an electrode provided by arranging an insulator in the internal surface of a cylinder head part, performing quickly and almost completely combustion of fuel in a cylinder. CONSTITUTION:Voltage is generated from a high voltage generating device 23, and the voltage is left as set by providing a switch in such a manner that the voltage is generated, after a piston 24 reaches a position before the top dead center, further discontinued to be generated in a position the piston 24 is lowered sufficiently from the top dead center. Accordingly, mixed gas of fuel from a carburetor is fed into a cylinder 17 and compressed following a rise of the piston 24, but when it rises to a position in the vicinity of the top dead center, a spark discharge is started between an electrode 19 and a head of the piston 24. This spark discharge is repeatedly performed further in the internal total body of a cylinder head part 16, so that gas, containing fuel, is ignited, and combustion, being performed when the piston 24 is started to lower down, is almost completely generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a spark ignition method for an internal combustion engine.

[Conventional technology]

A conventional ignition method for an internal combustion engine is shown in FIG. 5(A), for example.
, As shown in (B), a piston 12 connected to a crankshaft 11 is arranged in the cylinder IO so as to be able to rise and fall freely, and a spark plug 4 is arranged in the cylinder head 13, and the state shown in (A) of the figure is set. After the air mixed with fuel is mixed in and compressed by the piston 12 as shown in (B) of the figure, a spark is generated in the spark plug 14 to ignite the fuel and lower the piston to obtain rotational output. It was structured like this.

[Problems to be Solved by the Invention] However, the spark discharge of the spark plug 14 generates sparks at a distance of about 1 mm between the center electrode and the ground electrode called the side electrode that constitute the spark plug. Since this is the key ignition method, combustion waves propagate inward from the spark plug 14 at one end of the cylinder 10 in the cylinder constituting the combustion vessel. There was a problem in that it took a relatively long time (within Loss) until the combustion of the fuel in IO was completed.

For this reason, the larger the cylinder, the longer it will take for the combustion waves to propagate, so there is a limit to increasing the volume of a single cylinder. This has caused problems such as NOx emissions and reduced combustion efficiency, and in conventional internal combustion engines, NOx
Exhaust gas containing CO and CO is generated, creating problems such as the need to add special equipment for this treatment.

Here, a protrusion is formed at the upper center end of the piston, and an it
A method of igniting an internal combustion engine is currently in use, which causes an electric discharge to occur between the sparks, but since the path of the spark discharge is determined and the spark discharge is instantaneous, the above-mentioned problems can be solved by this method. It was not fully resolved.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an ignition method for an internal combustion engine that more effectively solves the above problems.

[Means for solving problems]

A method for igniting an internal combustion engine according to the present invention, which achieves the above object, includes arranging an insulator on the inner surface of at least the cylinder head and providing an electrode, and igniting by causing a direct and long-term spark discharge from the electrode to the upper surface of the piston. It is composed of

Here, the discharge from the electrode is to be performed continuously after confirming that the piston is above a predetermined position at the top of the cylinder, and to be discontinued after confirming that the piston has descended below the predetermined position. The present invention applies either to a device in which a predetermined high voltage is constantly applied between the piston and the electrode, and to cause a spontaneous discharge when the piston approaches the electrode beyond a predetermined position. Furthermore, the electrode may be provided at one or multiple points on the cylinder radius, or the entire electrode may be planar.

[Effect]

The method for igniting an internal combustion engine according to the present invention is to insulate the inside of the cylinder head. When the piston is positioned at the top of the cylinder, a direct and long-term spark discharge is caused from the electrode to the top surface of the piston, so that the combustion gas in the cylinder is directly ignited, resulting in short-term combustion. done within.

The spark discharge occurs continuously, and multiple sparks are generated at arbitrary locations scattered on the upper surface of the piston.As a result, even if the cylinder is large, the combustion gas inside the cylinder is normally It is ignited at a speed faster than the combustion propagation speed of , and may cause repeated spark discharges, ending combustion early.

Furthermore, the exhaust gas is also purified because combustion occurs smoothly even in areas where incomplete combustion has normally occurred or even in a lean mixture.

[Example] Next, examples embodying the present invention will be described with reference to the attached drawings to provide an understanding of the present invention.

Here, FIG. 1 is a sectional view of a main part of a cylinder of a gasoline engine embodying the ignition method for an internal combustion engine according to the present invention;
FIG. 2 is a graph showing the relationship between the generation rate of harmful gases and the air-fuel ratio, and FIGS. 3 and 4 are cross-sectional views of the main parts of the cylinder of other gasoline engines.

As shown in FIG. 1, alumina ceramic (^1ids-98%, electrical resistance-I
IOQcm, heat resistant temperature -1600°C 318 are placed.

An electrode 19 is arranged at the center of the cylinder head portion 16, and the periphery of the electrode 19 is fixed to an outer threaded cylinder 21 via an insulator 20 such as alumina.

A high voltage generator 23 that generates a voltage of several hundred thousand volts is connected to the mold 1119 via a high voltage cable 22.
It is connected to the.

Note that the alumina ceramic 18 and the insulator 20
It is assumed that the thickness is sufficient to withstand the above-mentioned high voltage.

The generated voltage from the high voltage generator 23 is generated by setting a switch so that the high voltage is generated after the piston 24 reaches a position just before the top dead center, and furthermore, when the piston 24 has fallen sufficiently below the top dead center. The voltage is set so that the generation of the high voltage is stopped at a position (this position is arbitrary), but considering the discharge start voltage determined by the distance, set 1 to 19.
It is theoretically possible to apply a suitable voltage between the piston 24 and the piston 24 at all times.

Therefore, gas mixed with fuel is sent from the carburetor into the cylinder 17 and compressed as the piston 24 rises, but when the piston 24 rises to near top dead center, the electrode 19 and the head of the piston 24 During this time, spark discharge begins.

This spark discharge is repeatedly discharged and is discharged throughout the interior of the cylinder head portion 16, so that the gas containing the fuel is ignited.Moreover, this discharge occurs even when the piston 24 starts to lower, so that the fuel is more completely removed. Combustion takes place.

Therefore, very stable combustion can be obtained even when the fuel gas has a low mixing ratio of lean fuel, for example, the mixing ratio (air/fuel) is about 17.5 to 18.

Figure 2 shows a graph showing the relationship between the generation rate of harmful gases and the mixture ratio (air-fuel ratio).
+) tends to decrease, and hydrocarbons (HC) also tend to decrease if they are below a certain value. It becomes possible to reduce hydrogen.

Further, according to experiments, it was confirmed that by configuring the internal combustion engine as described above, the combustion efficiency was improved by about 10 to 15%. This is because the spark discharge occurs continuously throughout the inner surface of the cylinder head, which ignites all of the fuel inside, increasing the combustion efficiency.

In the above embodiment, the electrode is connected to the cylinder head section 16.
However, as shown in Fig. 4, a plurality of electrodes 2
It is also possible to arrange the electrode 27 in the shape of a flat plate, as shown in FIG. It is possible, and it is also possible to provide appropriate protrusions or fin-like irregularities to facilitate discharge.

The high voltage generator 23 connected to these electrodes 19, 25, 26, 27 is normally constructed to generate high voltage on the secondary side by turning on and off the current in the coil on the secondary side. is preferable because it has a simple structure, but in some cases it is also possible to use an alternating current of 1ooOHz or more, which allows the discharge period to be within 0.5 ms, making it possible to perform a large number of discharges in one combustion. It is possible to make it happen.

Although the internal combustion engine according to the above embodiment is a two-stroke gasoline engine, the present invention is also applicable to a four-stroke gasoline engine. In this case, since the piston also rises during the exhaust process, it is preferable to provide the high voltage generator with a switch that does not generate spark discharge when unnecessary, so as to generate spark discharge only during the compression and explosion processes.

In addition, in the above example, alumina ceramic was used as the insulator, but any insulator (for example, zirconia, silicon nitride) can be used as long as it is heat resistant and has sufficient strength. It is.

Furthermore, when using a single abrader, the distance from the electrode to the piston head should be as close to the same distance as possible.
It is also possible to form the head part of the piston concavely.

[Effect of the Invention J Since the ignition method for an internal combustion engine according to the present invention is configured as described above, a direct and long-term discharge occurs between the electrode and the upper surface of the piston, so that the fuel in the cylinder is rapidly and
Moreover, it was almost completely combusted, and the combustion efficiency was improved.

In addition, since the fuel is ignited throughout the cylinder,
Combustion time is shortened and the engine can be rotated stably even with lean fuel without causing non-king, etc. Moreover, exhaust gas is purified, making it easier to start in winter and even at high altitudes. It became possible to drive the engine stably.

Since the combustion propagation distance is shortened, the volume of the 1-cylinder can be expanded, making it possible to manufacture a large engine using raw cylinders, and providing a highly efficient engine.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the main part of the cylinder of a gasoline engine embodying the ignition method for an internal combustion engine according to the present invention, FIG. 2 is a graph showing the relationship between the generation rate of harmful gases and the air-fuel ratio, and FIG.
4 are sectional views of the main cylinder parts of a gasoline engine according to another embodiment, and FIGS. 5(A) and 5(8) are sectional views of an internal combustion engine according to a conventional example. [Explanation of symbols] 16-...- cylinder head section, 17-...
・Cylinder, 18 ・・・・Alumina ceramic (insulator), 19 ・・・・Electrode, 20 ・
--- Insulator, 21 --- Screw tube, 22
・・・・・・－High voltage cable, 23 ・・・・・・
High voltage generator, 24... Piston, 25.
26.27 ...-- Electrode agent Patent attorney Fujio Chubu

Claims (1)

[Claims] (1) A method for igniting an internal combustion engine, which comprises arranging an insulator and providing an electrode on at least the inner surface of the cylinder head, and igniting the engine by causing a direct and long-term spark discharge from the electrode to the upper surface of the piston.