JPS6053191B2 - Internal combustion engine with spark plug - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spark-ignition internal combustion engine, and is intended to improve the carbon fouling resistance of a spark plug installed in the internal combustion engine.

FIG. 1 shows the structure of a conventionally known spark plug.

In this structure, the metal frame 1 and the legs 2a of the insulator 2
) The space 6 formed by the packing 5 and whose opening portion 6a is open in the direction of the ground electrode 4 is usually 0.3 to 0.
It has a volume of 5 cC. Further, the opening portion 6a of this space 6 has an opening area of 0.35 to 0.5ai. The same applies to the spark plug shown in FIG. During the compression stroke of the internal combustion engine, new air-fuel mixture flows into this space 6, so that a flow occurs in the direction of the arrow shown in FIG.

The speed of this flow varies depending on the internal combustion engine and the type of plug, but if the cylinder inner diameter is 95m77, the stroke distance is 72m.
Lol! n In an internal combustion engine with a compression ratio of 7:2, the volume of the space 6 is O,
35CC) Opening area O of opening portion 6a of space 6, 36
If a cfi plug is used, the values shown in FIG. 3 will be obtained. This flow rate increases or decreases in proportion to the rotational speed of the internal combustion engine, but normally,
100~ before top dead center (TDC) where the spark flies to the spark plug
400 becomes 1! -1,/sec to 3Wl,/sec, and becomes faster as the angle advances. Immediately after a spark flies into the spark gap 7 of the ignition plug and ignites the air-fuel mixture, the initial flame speed is slow at several tens of crn/sec, so the flame cannot propagate upstream and downstream. It propagates at a speed that is the sum of the flame speed and the flow speed. Therefore, at the initial stage of ignition, the flame develops in the direction of the space 6 of the plug. This tendency is strong on the leading side of the ignition angle (40 BTDC) where the flow velocity is high, and is strong on the lag side (100 BTDC) where the flow velocity is low.
C10CBTT) C) is weak. The burned gas from the previous combustion cycle remains in the space 6.
This gas exists in a mixed state with a new air-fuel mixture, and combustion heat is further removed by the stopper 1 around the space 6, so incomplete combustion is likely to occur in the space 6. Therefore, a plug in which the volume of the space 6 is large and the opening 6a of the space 6 is wide open toward the spark gap 7 side is likely to cause the incomplete combustion described above due to flame propagation, and as a result, the leg 2a of the insulator 2 Carbon adheres to the surface of the fuel, causing poor insulation and causing misfires. In view of the above points, the present invention provides a ventilation hole in the cylinder wall where the ignition plug is installed, and a communication hole in the plug body of the ignition plug. By making the ventilation holes communicate with each other and directing one end of the ventilation hole toward the intake valve opening formed when the intake valve of the internal combustion engine opens, new air-fuel mixture flows into the space through both holes during the compression stroke. As a result, the inflow velocity of the new air-fuel mixture flowing into the opening of the space 6 decreases, creating an atmosphere in which incomplete combustion is less likely to occur within the space, and the new air-fuel mixture flowing into the space 6. It is an object of the present invention to provide an internal combustion engine in which the initial flame at the time of initial ignition does not propagate to the opening part due to the flow velocity of air, and the spark plug can be prevented from being contaminated with carbon.

Examples of the present invention will be described below.

In FIG. 4, an insulator 2 is fixed to the inside of a metal stopper 1 via a ring-shaped metal packing 5. As shown in FIG. A center electrode 3 is held on a leg portion 2a of this insulator 2 that is exposed inside a combustion chamber 17 of an internal combustion engine. The end side of the ground electrode 4 fixed to the end of the stopper 1 faces the tip of the center electrode 3, and a spark gap 7 is formed between the two. A space 6 formed by the leg portion 2a1 of the insulator 2, the plug 1, and the packing 5 opens into the combustion chamber 17 in the direction of the spark gap 7. The plug body 1 is provided with a communication hole 8 that opens at one end in the inner part of the space 6 near the packing 5 and whose other end opens to the outside of the plug body 1. Further, a ring-shaped ventilation groove 9 is provided in the cylinder wall 10 of the internal combustion engine to which the spark plug having the above configuration is installed via the packing 12, and one end opens into the combustion chamber 17 and the other end opens into the ventilation groove 9. A vertical hole 11 is provided which opens into the vertical hole 11 . The end of the ventilation groove 9 opens into the spark plug mounting portion 10a of the cylinder wall 10 and communicates with the end of the communication hole 8 of the plug body 1. Therefore, the inside of the combustion chamber 17 and the inside of the space 6 are communicated through the communication hole 8, the ventilation groove 9, and the vertical hole 11. The operation of the above configuration will be explained.

Inside the space 6, there are two conditions: (a) a relatively large amount of burned gas from the previous cycle is mixed into the new air-fuel mixture, and (b) combustion heat is easily lost to the plug body around the space 6. If a relatively low-temperature initial flame propagates into the space 6 in such a state, incomplete combustion will occur, causing carbon contamination. If carbon adheres to the leg portion 2a up to the packing 5, the current from the center electrode 3 will leak to the stopper 1 through the carbon and the packing 5, preventing the spark from flying in the spark gap 7 and causing a misfire. wake up However, in this embodiment, the vertical hole 11 and the ventilation groove 9 are closed during the compression stroke.
, and through the communication hole 8, the new air-fuel mixture is injected and introduced into the space 6 near the packing 5, and the space 6
Since burnt gas exists within the space 6, the flow velocity of the new air-fuel mixture flowing in from the opening 6a of the space 6 decreases.

Therefore, at the initial stage of ignition, if the initial flame propagates in the direction of the space 6 with the flow velocity, it will hardly develop, and even if the initial flame spreads, the packing 5 in the space 6
Since a new air-fuel mixture exists in the vicinity of the packing 5, the atmosphere is such that incomplete combustion is difficult to occur in the vicinity of the packing 5, and carbon is difficult to generate in the inner part of the insulator 2, including the packing 5. Therefore, misfires are less likely to occur.
In this embodiment, it is preferable that the ventilation resistance of the communication hole 8, the ventilation groove 9, and the vertical hole 11 is smaller than the ventilation resistance of the opening portion 6a of the space 6, but this does not apply to the present invention. There are no restrictions. FIG. 5 shows another embodiment of the present invention in which a re-wag-shaped ventilation groove 9 is provided inside the cylinder wall 10. According to this embodiment, compared to the previous embodiment, combustion gas is prevented by a packing 12. No need to seal.

In FIG. 6, this FIG. 6 shows the features of the main part of the present invention, and the basic structure is the spark plug structure and cylinder wall 10 structure shown in FIG. The direction of the end of the vertical hole 11 is aligned with the intake valve opening formed when the intake valve 18 is opened (intake valve 18 and valve seat 19).
(the gap between the two) 20. In addition,
13 is a spark plug, 14 is a cylinder head, 15 is a piston, 16 is a cylinder block, and 21 is an intake boat provided on the cylinder head 14, respectively. According to this configuration, during the intake stroke, the new air-fuel mixture is sucked into the combustion chamber 17 through the intake boat 21 and the intake valve opening 20 between the intake valve 18 and the valve seat 19 as the piston 15 descends. .

At this time, the new air-fuel mixture flows in the direction of the arrow shown in FIG.
The air flows through the intake valve opening 20 in a direction perpendicular to the circumference of the intake valve 18 along. For this reason, the vertical hole 1 of the cylinder wall 10
The new air-fuel mixture efficiently flows into the space 6 of the spark plug 13, the burned gas remaining in the space 6 of the spark plug 13 is discharged, improving ventilation, and the space 6 is filled with the new air-fuel mixture. The combustion atmosphere inside the tank is improved, and the effect of preventing carbon pollution is greatly improved. In each of the embodiments described above, an annular constriction portion may be provided inside the plug body 1 to reduce the opening area of the opening portion 6a of the space portion 6.

With this configuration, the vertical holes 11.
The amount of new air-fuel mixture flowing into the space 6 of the spark plug through the ventilation groove 9 and the communication hole 8 increases, and the speed of inflow of the new air-fuel mixture from the opening 6a of the space 6 is significantly reduced. This ensures that the initial flame is prevented from spreading. Also,
The multi-gap spark plug shown in Fig. 2 has poor ignition performance and is more prone to carbon contamination than conventional spark plugs, and is suitable for use in internal combustion engines using lean mixtures, internal combustion engines with a pre-chamber, etc.
It is used in rotary internal combustion engines and the like, and it is very effective to apply the present invention to this multi-gap spark plug.

Further, in each of the embodiments described above, one vertical hole 11 is provided in the cylinder wall portion 10, but a plurality of vertical holes 11 may be provided.

In this case, it goes without saying that the number of ventilation grooves 9 and communication holes 8 corresponds to the number of vertical holes 11. Moreover, it goes without saying that the vertical hole 11 may be formed into a ring shape like the ventilation groove 9. As detailed above, according to the present invention, the ventilation holes (9, 11) are provided in the cylinder wall portion 10 to which the spark plug is mounted, and the communication hole 8 is provided in the plug body 1 of the spark plug. 8 and ventilation holes (9, 11) to communicate the inside of the spark plug space 6 and the inside of the combustion chamber 17, and one end of the ventilation hole (9, 11) is formed when the intake valve 18 of the internal combustion engine is opened. Therefore, during the intake stroke of the internal combustion engine, the new air-fuel mixture flowing through the intake valve opening 20 is efficiently directed to the space through the communication hole 8 and the ventilation hole (9, 11). Furthermore, during the compression stroke of the internal combustion engine, a new air-fuel mixture is introduced into the space 6 through the communication hole 8 and the ventilation holes (9, 11), and an incomplete amount of air-fuel mixture is introduced into the space 6. As the atmosphere becomes less conducive to combustion and a large amount of new air-fuel mixture is introduced into the space 6, the flow velocity of the new air-fuel mixture flowing in from the opening 6a of the space 6 decreases, and the new air-fuel mixture flows by riding on this flow velocity. The initial flame at the time of initial ignition hardly spreads to the opening portion 6a, thus preventing the spark plug from being contaminated with carbon.

[Brief explanation of drawings]

Figure 1a is a sectional view showing the main parts of a conventional spark plug.
Figure b is a bottom view of Figure 1 a, Figure 2 a is a sectional view showing the main parts of a conventional multi-gap spark plug, and Figure 2 b is a bottom view of Figure 1 a.
The bottom view of Fig. a, Fig. 3 is a characteristic diagram showing the inflow speed of the new air-fuel mixture into the spark plug space during the compression stroke, and Fig. 3 is for explaining the conventional method, and Fig. 4 is the ignition used in the embodiment of the present invention. FIG. 5 is a cross-sectional view showing the main parts of a plug, FIG. 5 is a cross-sectional view showing the main parts of another embodiment of the present invention, and FIG. 6 is a cross-sectional view showing the main parts of one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Plug body, 2... Insulator, 2a... Leg part, 3...
... Center electrode, 4 ... Ground electrode, 5 ... Packing,
6... Space portion, 6a... Opening portion, 8... Communication hole, 9, 11... Ventilation groove forming ventilation hole, vertical hole, 10.
...Cylinder wall, 10a... Mounting part, 13... Spark plug, 17... Combustion chamber, 18... Intake valve, 20...
...Intake valve opening.

Claims (1)

[Claims] 1. A metal stopper, an insulator fixed to the inside of the stopper through a packing, a center electrode provided on a leg of the insulator that is exposed to the combustion chamber of an internal combustion engine, and a center electrode attached to the stopper. a spark plug having a ground electrode provided therein; one end opening in a space formed by the plug body, the packing, and the legs of the insulator and opening into the combustion chamber; A communication hole having an end opening to the outside of the plug body is provided in the plug body, and the cylinder wall portion to which the spark plug is attached has one end opening into the combustion chamber and the other end opening into the spark plug adhesive part. A ventilation hole is provided in the cylinder wall, and the space of the spark plug communicates with the combustion chamber through the ventilation hole in the cylinder wall and the communication hole in the plug body of the spark plug, and the ventilation hole in the cylinder wall communicates with the combustion chamber. 1. An internal combustion engine having a spark plug, characterized in that one end of the spark plug is oriented in the direction of an intake valve opening formed when the intake valve is opened.