JPH0454355B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a mixed gas combustion method for an internal combustion engine in which mixed gas in a cylinder is ignited by a spark from an ignition plug to burn the mixed gas.

``Prior Art'' As shown in Fig. 1, the basic method of igniting a spark plug is to weld it to one end of the center electrode 1 of the spark plug provided at the top of the cylinder of an engine and to a metal fixing part 3, and to form an L-shaped spark plug. A suitable plug gap L1 (usually 0.7 mm) is provided between each end of the ground electrode 2, which is a square bar-shaped ground electrode 2 whose end face is rectangular and has a rectangular shape.
When the engine is operated, a spark is generated in the plug gap L1 by energizing the center electrode 1 from a terminal 5 provided through a ceramic insulator 4 at appropriate times, causing the mixed gas in the cylinder to ignite and explode.

``Problems to be Solved by the Invention'' In such a spark plug, conventionally, as shown in FIGS. 2 and 3, the rectangular ground electrode 12 bent into an L-shape is attached to a fixed portion 13 welded to each other. A continuous flat plate is formed from the to the tip facing the center electrode 11, and the spark between each electrode 11 and 12 burns the mixed gas at the spark generation position 1A, causing the fire to spread to the piston side 1B.

In the above conventional technology, the mixed gas in the cylinder becomes turbulent combustion except for the initial combustion immediately after ignition, and after the flame has developed to a certain extent, the combustion speed is accelerated in proportion to the turbulence of the flame spread gas. During the initial combustion stage, the development of the flame is not affected by the turbulence of the mixed gas, so the initial combustion speed is slow until the flame grows to a certain extent, and therefore the overall combustion time from the ignition timing to the final stage of combustion is It is not possible to shorten the length easily, and this poses problems such as the difficulty of accelerating the combustion rate, increasing engine efficiency, and improving fuel efficiency.

"Means for Solving the Problems" However, the present invention provides a combustion method in which a ground electrode is disposed opposite to the tip of a center electrode, and a spark is generated between these to ignite a mixed gas in a cylinder.
The flame kernel formed by the generation of a spark is used as a first pilot flame, and the first pilot flame is used as the first pilot flame through means for communicating the fuel concentration part formed on the piston side of the ground electrode with the plug gap over a short distance as possible. A second pilot flame is formed by burning the mixed gas in the fuel concentrated part earlier than other mixed gases in the cylinder using a fire, and the mixed gas in the cylinder is combusted by the second pilot flame. That is.

``Effect'' Therefore, the fuel concentrated part is communicated with the plug gap over a short distance as possible, and the mixed gas in the fuel concentrated part is combusted earlier than other mixed gases in the cylinder, so that the flame formed by the spark is reduced. The second pilot flame, which has stronger firepower than the first pilot flame which is the core, can be easily obtained in the fuel concentration part, and the combustion speed at the initial stage of combustion of the mixed gas in the cylinder can be significantly accelerated, compared to the conventional method. The initial combustion time of the mixed gas in the cylinder can be easily shortened, the mixed gas in the cylinder can be completely combusted at a faster combustion rate than before, and high combustion efficiency and extremely excellent fuel efficiency can be obtained.

"Embodiments" Examples of the present invention will be described below in detail based on the drawings. 4 to 7 show an embodiment of the present invention, in which a ground electrode 32 bent into an L-shape has one end facing one end of the center electrode 31, and a suitable distance between each end. While forming a plug gap, the other end of the ground electrode 32 is welded and fixed to a fixing part 33.

This ground electrode 32 has a plurality of gas holes 36 that pass through the spark generation position 3A near the plug gap and the piston side 3B, and the ground electrode 32 has both longitudinal sides on the L-shaped tip side. Bend each toward the piston side 3B to form the bent portion 3
7, 37, and a fuel concentration part 39 is provided on the opening side of the piston side 3B of the plurality of gas holes 36..., which communicates with the gas holes 36... and opens to the piston side 3B. Bending portion 37, 3
A tapered surface 38 that slopes downward (toward the piston side) is provided on the spark generation position 3A side and the piston side 3B of No.7.
38 respectively, and the center electrode 3
The width of the ground electrode 32 perpendicular to the axial direction of the center electrode 31 is formed to be larger than this thickness, and
The gas hole 36 penetrates in the axial direction of the center electrode 31.
The bent portions 37, 37 are formed approximately at the center in the lateral direction of the surface of the ground electrode 32, which is provided opposite to the center electrode 31, and both longitudinal edges of the ground electrode 32, which is provided opposite to the center electrode 31, are bent toward the piston side 3B. The surface of the ground electrode 32 facing the center electrode 31 has a trapezoidal convex shape, and the surface of the ground electrode 32 on the opposite side has a trapezoidal concave shape.
A piston side 3 formed continuously in the longitudinal direction of the ground electrodes 32 and surrounded by a trapezoidal concave surface of the ground electrodes 32.
The fuel concentrated portion 39 of B is communicated with the spark generation side 3A through the gas hole 36, and the inner diameter of the gas hole 36 is made smaller than the width of the flat part of the trapezoidal convex surface of the ground electrode 32.

The present embodiment is constructed as described above, and by generating a spark in the plug gap between the center electrode 31 and the ground electrode 32, the mixed gas in the plug gap is combusted, and combustion occurs on the spark generation side A of the ground electrode 32. The gas is repelled by the tapered surface 38 of the bent portion 37, which is a trapezoidal convex surface, and diffuses in a turbulent flow, accelerating the combustion speed at the initial stage of ignition on the spark generation side 3A, and serves as a first pilot flame with low thermal power. Simultaneously with the spark generation, the mixed gas in the fuel concentration section 39 is combusted through the gas hole 36.

Since the mixed gas in the concentrated portion 39 has a small volume, it is combusted in an extremely short time, and the combustion gas becomes a second pilot flame with a large firepower, and the trapezoid on the piston side 38 of the ground electrode 32 forming the concentrated portion 39 is formed. The combustion gas repulses against the tapered surface 38 of the concave bent portion 37 and expands in the direction of the piston side 3B and the inner surface of the cylinder, accelerated by this expansion pressure, accelerating the flame propagation speed at the initial stage of ignition, and increasing the initial stage of the mixed gas. Combustion can be completed early and the overall combustion time from ignition timing to the end of combustion can be shortened.

As described above, when a spark is generated between the center electrode 31 and the ground electrode 32 and the mixed gas is ignited, the mixed gas in the fuel concentration section 39 provided on the ground electrode 32 is also ignited almost simultaneously with the spark generation. Gas hole 36
To describe this in slow motion, at the start of combustion, expansion gas is naturally generated in the concentrated portion 39 due to combustion of the mixed gas, and the expansion pressure is applied to the fuel concentrated portion 39.
The expansion speed of the combustion gas is accelerated by being restricted by the bottom surface and slopes on both sides of the fuel concentrating portion 39, and the unburned gas in the fuel concentrating portion 39 is While burning this together with the mixed gas, the fire protrudes and spreads.

That is, if the spark is generated by the first pilot flame, the fuel concentrated portion 39 ignited by this pilot flame
The mixed gas is a small amount, burns quickly, and becomes a second pilot flame with strong firepower accelerated by the expansion force of the combustion gas, which spreads the fire and can significantly burn the mixed gas in the cylinder. The function of the concentration section 39 can be said to be to add flame propagation acceleration force to the firepower.

As is clear from the above, in the combustion method in which the ground electrode 32 is disposed opposite to the tip of the center electrode 31 and a spark is generated between them to ignite the mixed gas in the cylinder, the flame kernel formed by the generation of the spark is The first pilot flame is used to fuel the fuel via the gas hole 36, which is a means for communicating the fuel concentration part 39 formed on the piston side of the ground electrode 32 and the plug gap over a short distance as possible. The mixed gas in the concentrated portion 39 is combusted earlier than other mixed gases in the cylinder to form a second pilot flame, and the second pilot flame is formed.
The mixed gas inside the cylinder is combusted using a pilot flame.

In gasoline reciprocating internal combustion engines, one of the best ways to achieve fuel efficiency is to quickly burn the mixed gas in the cylinder, and ideally during engine operation, at the end of the compression stroke, The combustion occurs at the same time as ignition near the top dead center, and the combustion gas reaches the highest pressure and moves to the working stroke.However, no matter how good the flammability of the mixed gas is at present, it takes some time for combustion to occur. However, in current gasoline internal combustion engines, the ignition timing is adjusted and set before the compression stroke reaches top dead center, and a spark is generated and ignited inside the cylinder. Combustion of the mixed gas begins, and when the crank stroke slightly exceeds top dead center, the combustion gas is set to reach maximum pressure and move to the working stroke, but from the time it is ignited, it reaches top dead center. During this period, the piston moves against the combustion gas expansion pressure generated by the combustion of the mixed gas to obtain the maximum pressure.The energy required to resist the combustion gas pressure results in an output loss of the internal combustion engine, and The idea behind the invention is to provide a fuel concentration section 39 in order to reduce this power loss, and its function generates a flame spreader gas that acts as a second pilot flame to accelerate the fire spread rate and has a strong firepower. It enables early combustion of mixed gas, and because it has a fast combustion effect, it is necessary and possible to delay the ignition timing compared to when using conventional spark plugs.
This adjustment reduces energy loss due to resistance to the gas pressure that burns and expands during the period from ignition to the maximum pressure at top dead center, improving engine efficiency and achieving fuel savings.

"Effects of the Invention" As is clear from the above embodiments, the present invention provides a combustion method in which a ground electrode 32 is disposed opposite to the tip of a center electrode 31, and a spark is generated between them to ignite a mixed gas in a cylinder. The flame kernel formed by the generation of a spark is used as a first pilot flame, and the fuel concentration portion 39 formed on the piston side of the ground electrode 32 and the plug gap are communicated with each other over a short distance as possible. The first pilot flame burns the mixed gas in the fuel concentration part 39 earlier than the other mixed gases in the cylinder to form a second pilot flame, and the second pilot flame burns the mixed gas in the cylinder. The fuel concentrator 39 is connected to the plug gap.
Because the mixed gas in the fuel concentration part 39 is combusted earlier than other mixed gases in the cylinder, compared to the first pilot flame which is the flame nucleus formed by the spark. A second pilot flame with strong firepower can be easily obtained in the fuel concentration section 39, and the combustion speed of the mixed gas in the cylinder at the initial stage of combustion can be significantly accelerated, compared to the conventional method. The combustion time can be easily shortened, the mixed gas in the cylinder can be completely combusted at a faster combustion speed than before, and high combustion efficiency and extremely excellent fuel efficiency can be obtained.

[Brief explanation of the drawing]

Fig. 1 is an overall cross-sectional view showing a conventional example, Fig. 2 is an enlarged cross-sectional view of the main part thereof, Fig. 3 is a bottom view of Fig. 2, and Fig. 4 is a schematic diagram showing an embodiment of the present invention. 5 is a bottom view of FIG. 4, FIG. 6 is an enlarged view taken along line C-C of FIG. 4, and FIG. 7 is an enlarged view of FIG.
It is a sectional view taken along the line D. 31...center electrode, 32...ground electrode, 36...
...Gas hole, 39...Fuel concentration part.

Claims (1)

[Claims] 1 In a combustion method in which a ground electrode is placed opposite the tip of the center electrode and a spark is generated between them to ignite the mixed gas in the cylinder, the flame kernel formed by the generation of the spark is used as the first pilot flame and the ground electrode is connected to the ground electrode. Through a means for communicating the fuel concentrated portion formed on the piston side of the electrode and the plug gap over a short distance as possible, the first pilot fire causes the mixed gas in the fuel concentrated portion to be lower than the other mixed gas in the cylinder. A mixed gas combustion method for an internal combustion engine, characterized in that a second pilot flame is formed by early combustion, and the mixed gas in a cylinder is combusted by the second pilot flame.