JPS5923635B2 - spark plug - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention supplies secondary air into the cylinder when the pressure inside the cylinder drops in an internal combustion engine, particularly a gasoline engine, to lower the temperature inside the cylinder and reduce unburned gas remaining inside the cylinder. The present invention relates to a spark plug having an air introduction passage that can reduce pollutants in exhaust gas by completely combusting the fuel, and improve fuel efficiency.

In an internal combustion engine, unburned residual gas remains in the cylinder after the explosion stroke, which increases the temperature.
It is known that this has a significant impact on engine performance, and due to the high temperature inside the cylinder, this unburned gas generates nitrogen oxides, which are discharged outside the engine during the exhaust stroke, resulting in so-called exhaust gas. It is also well known that it causes pollution.

Therefore, attempts have been made to blow air into the cylinder in order to secondarily combust this unburned gas within the cylinder, but none of these have reached the level of practical use.

It has been found that the pressure in the cylinder is locally reduced at the moment of the explosion-exhaust stroke.

This pressure drop phenomenon is thought to be due to the pressure drop of burned gas during the propagation of the fire.

According to the present invention, it is possible to capture the above-mentioned moment and blow secondary air into the cylinder, and since it can be easily realized without making any modifications to the internal combustion engine itself, its effectiveness is high. is extremely high.

An embodiment of the present invention will be described below with reference to the drawings.

Reference numeral 1 denotes a center electrode provided at the center of the spark plug body 2, which is divided into an upper center electrode 1a and a lower center type ff11b, and has an enlarged portion 3 below the lower center electrode 1b and extends from the tip to the end. It has holes 4a and 4b penetrating through it.

A screw thread 3a is formed on the lower inner wall of the enlarged portion 3 of the upper center electrode 1a, and a large diameter portion 1d (electrode 1b Through hole 4
b) are fitted.

Inside the enlarged part 3, there is a valve seat 6 made of a sintered body with a center hole 5 bored therein, and a short tube 7 made of a heat-resistant, low heat conductive metal that supports the valve seat 6 by pressure on the upper end of the enlarged part 3. A movable valve 10 made of a sintered body consisting of a pointed head 8 and a cylindrical body 9 is installed inside the short pipe 7, and the large diameter part 1d of the lower center electrode 1b is connected to the lower part of the enlarged part 3. The seating surface 3 of the large diameter portion 1d is screwed onto the thread 3a.
A valve chamber is constructed in which a valve seat 6 is press-fitted to the upper end of the enlarged portion 3 via a short pipe 7 seated on the valve seat 4 .

Furthermore, the movable valve 10 has pointed portions 8 on the left and right sides of the outer periphery of the cylindrical body portion 9.
A vertical groove 11 is provided that reaches the lower end of the cylindrical body 9, and this vertical groove 11 bends in the diametrical direction at the lower end of the cylindrical body and reaches a blank hole 12 formed inside the cylindrical body 9. ing.

In the figure, 29 is a hook type electrode, 30 is a cylinder mounting screw portion, 31 is a washer, 32 is an insulator portion, and 33 is a high voltage wire terminal portion.

Since the spark plug of the present invention is constructed as described above, it can be mounted as is in a predetermined position of an internal combustion engine.

The operation will now be explained as follows.

When the pressure inside the cylinder is high, the movable valve 10 receives the pressure inside the cylinder through its blind hole 12, slides inside the short pipe 7, and is positioned in the direction of the valve seat 6, with the pointed head 8 facing the valve seat 6. The center hole 5 of the cylinder is sealed to prevent pressure inside the cylinder from leaking to the outside.

Next, when the pressure inside the cylinder momentarily becomes negative, the leaflet 8 of the movable valve 10 separates from the valve seat 6 and connects to the lower center electrode 1b.
slides inside the short tube 7 in the direction of the seating surface 34 of the large diameter portion 1d.

At this time, the secondary air entering from the upper end of the through hole 4a of the upper center electrode 1a passes through the vertical groove 11 provided in the outer cylinder of the cylindrical portion of the movable valve 10, passes through the through hole 4b of the lower center electrode 1b, and enters the cylinder. This is something that is sent within the country.

According to the present invention, the movable valve 10 automatically opens and closes the center hole 5 of the valve seat 6 in response to pressure changes within the cylinder, and furthermore, the movable valve 10 opens and closes the center hole 5 of the valve seat 6 and the movable valve seat 6 constituting the valve chamber. Since the valve 10 is made of a sintered body, it can withstand the conduction heat inside the cylinder and will not wear out even if it follows the cylinder's operating cycle.The short pipe 7 is made of heat-resistant material such as stainless steel. Since the movable valve 10 is made of a metal with low heat conductivity, thermal expansion of the movable valve 10 is prevented, and the sliding movement of the movable valve 10 is made smooth. The cross-sectional area of the groove can be kept constant, and the introduction of secondary air, which is the object of the present invention, can be carried out very accurately.

In an internal combustion engine equipped with the spark plug of the present invention, the pressure drop of burnt gas in the cylinder opens the valve hole and blows air into the cylinder, so that the residual gas that tends to stay in the cylinder is pushed out by this air flow. The air is then replaced by relatively low temperature secondary air.

Therefore, the weight and temperature of the burned gas in the cylinder are extremely reduced, and the introduced secondary air is fully useful for combustion in the subsequent explosion stroke, so that volumetric efficiency, charging efficiency,
Effective pressure etc. are substantially improved, fuel consumption can be greatly reduced, and since the temperature inside the cylinder and the exhaust temperature after the exhaust stroke are lowered, the production of nitrogen oxides is reduced.

According to the experimental results, it was as follows.

As a result of a driving test conducted using a passenger car equipped with a gasoline engine having the performance shown in Table 1, the fuel efficiency rate was compared to that of a car equipped with a commercially available regular spark plug, as shown in Table 2.

As explained above, the spark plug according to the present invention can be installed in a commercially available internal combustion engine without the need for any modification, and the valve body in the valve chamber automatically moves into the valve chamber by the pressure difference caused by the explosion-exhaust stroke. Since the valve slides without being affected by other factors, the valve hole can be opened and closed in accordance with the cycle of the engine, allowing outside air to be introduced effectively.

Furthermore, the present invention does not cause abnormal explosions due to airtight leaks, and its durability is extremely useful for dogs.

[Brief explanation of the drawing]

FIG. 1 is a partially vertical front view of the spark plug of the present invention, FIG. 2 is an exploded perspective view of a valve chamber portion, and FIG. 3 is a perspective view of a movable valve. 1... Center electrode, 3... Ampulla, 4.
...Through hole, 5... Center hole of valve seat 6, 7
...Short pipe, 8...Pointed head, 9...
... Cylinder part, 10 ... Movable valve, 11 ...
・Vertical groove, 12... Blind hole, 34...
Seating surface.

Claims (1)

[Claims] 1. A through hole is formed to serve as an air introduction passage, and consists of an upper and a lower center electrode that are screwed together, and the center hole is bored inside the enlarged part formed in the screwed part of each center electrode. It is composed of a valve seat made of a sintered body, a short tube made of a heat-resistant, low heat conductive metal that supports the valve seat, and a pointed head and a cylindrical body that slide inside the short tube. An ignition plug characterized in that it has a valve chamber made up of a movable valve made of a sintered body with a plurality of vertical grooves provided on the outer periphery of the body.