JP4156614B2 - Internal combustion engine - Google Patents

Description

The present invention, improvement in fuel consumption is about the internal combustion agencies as possible.

In recent years, in order to improve fuel efficiency of internal combustion engines such as automobile engines, the internal combustion engines have been driven by lean burn or direct fuel injection. In such an internal combustion engine (hereinafter also simply referred to as an engine), it is desired to improve the ignitability of a spark plug (hereinafter also simply referred to as a plug) and to reliably ignite the air-fuel mixture.
By the way, in the conventional engine, the phase of the female screw formed in the plug mounting hole formed in the cylinder head and the male screw formed in the mounting screw portion of the metal shell of the plug is not particularly defined. Therefore, when the plug is screwed into the plug mounting hole, the circumferential position of the outer electrode fixed to the tip of the mounting screw exposed in the cylinder cannot be determined. That is, by the combination of the cylinder head and the plug, the circumferential position of the outer electrode can be any position within a range of 360 degrees.

  However, as described above, in the case of driving by lean burn or direct fuel injection, a rich (high fuel ratio) mixture flow (swirl) that can be ignited is formed, and the center electrode and the outer electrode of the plug Since the swirl is designed so that the swirl passes through the discharge region, if the fixing position of the outer electrode is on the upstream side of the swirl, it is difficult for the rich air-fuel mixture to flow into the discharge region, and misfire is likely to occur. Therefore, in this case, the engine can be driven only in a range where the A / F (Air / Fuel) value is relatively small, and the fuel consumption is reduced.

  For example, the following test was performed on a four-valve engine E as shown in FIG. In this engine E, the two valves IN1, 2 on the right side in the figure are on the intake (intake) side, and the two left valves EX1, 2 are on the exhaust (exhaust) side. At this time, the air-fuel mixture M1 indicated by the arrow supplied from the right side in the figure is led into the cylinder C from the valves IN1 and 2, and flows in the leftward swirl indicated by the arrow M2 in the center in the figure. The exhaust gas N1 is exhausted through the valves EX1 and EX2 as indicated by arrows. In addition, description of the plug P was abbreviate | omitted in Fig.26 (a). However, the x mark in the center of the cylinder C is the discharge region of the spark plug P. When this is viewed from the side of the engine E, it is as shown in FIG. 26 (b), and the swirl M2 has a discharge region between the center electrode PI and the outer electrode PO of the plug P attached to the cylinder head CH. It is made to pass.

  Using such an engine E, the limit A / F value was measured using the plug P in which the circumferential position of the fixing portion POa of the outer electrode PO was changed. First, the case where the spark plug P having one pole (one outer electrode PO) is used will be described. As shown in FIG. 27A, when seen from the axial front end side of the plug P, the intersection of the stream line Lm of the swirl M2 passing through the center O of the mounting screw portion distal end portion PTe and the mounting screw portion distal end portion PTe. Among them, the circumferential position of the fixed portion POa of the outer electrode PO fixed to the mounting screw tip end portion PTe when measured in the counterclockwise direction with the upstream intersection S as a reference is indicated by an angle θ (deg). .

Then, as shown in FIG. 27B, the limit A / F value was almost constant (a1) except for the range of θ = −30 to +30, but in the range of θ = −30 to +30, The limit A / F value decreases, and when θ = 0, the limit A / F value decreases to a2. That is, in this range, it can be understood that the operation is not performed unless the air-fuel mixture is relatively rich. This is understood to be because the swirl M2 is prevented from passing through the discharge region between the center electrode PI and the outer electrode PO because the fixing portion POa of the outer electrode PO is on the upstream side of the swirl M2.
Therefore, in order to enable the engine E to operate at any angle θ, that is, in any circumferential position of the fixing portion POa of the outer electrode PO, the limit A / F value is limited to a2 value. It cannot be used.
In addition, as a measuring method of the limit A / F value, the following method was used. That is, the plug P is attached and the angle θ is measured, and then the engine E is operated, and the air-fuel mixture is gradually thinned to increase the A / F value. Then, the plug P misfires, and the rotational speed of the engine E begins to fluctuate. Therefore, the A / F value when the fluctuation of the rotational speed becomes 10% is set as the limit A / F value. This was measured for various angles θ by replacing the plug P, and the graph shown in FIG. 27B was obtained.

  Similarly, measurement was performed using a two-pole spark plug P having two outer electrodes PO1, 2 fixed at positions different from each other by 180 degrees. The method for determining the angle θ is the same as in the case of one pole. That is, as shown in FIG. 28 (a), when viewed from the tip end side in the axial direction of the plug P, the streamline Lm of the swirl M2 passing through the center O of the tip end portion PTe of the attachment screw portion, and the tip end portion PTe of the attachment screw portion. With respect to the intersection S of the upstream side, the circumferential position of the fixed portion POa (PO1a in FIG. 28A) of the outer electrode PO fixed to the tip end portion PTe of the mounting screw is defined as an angle θ (deg). ).

Then, as shown in FIG. 28B, the limit A / F value is almost constant (a3) except for the ranges of θ = −30 to +30 and θ = + 150 to +210 (= −150 to −210). However, in the range of θ = -30 to +30 and +150 to +210, the limit A / F value decreases, and in the case of θ = 0 and 180, the limit A / F value decreases to a4. That is, in this range, it can be understood that the operation is not performed unless the air-fuel mixture is relatively rich.
Therefore, in order to enable the engine E to operate at any angle θ, that is, in any circumferential position of the fixing portions PO1a and PO2a of the outer electrodes PO1 and PO2, a4 is set as a limit A / F value. It can only be used up to the value of. Here, in order to adjust the position of the outer electrode PO of the plug P to a desired position, a method of adjusting the tightening torque of the plug P can be considered, but an appropriate tightening torque is determined for tightening the plug ( For example, ISO 1919: 1988 (E) etc.) may not be adjusted in all cases.
In addition, when the torque is insufficient or overtightened, the function of the plug may not be achieved.

The present invention was made in view of the problems described above, it can be driven even thin mixture (high A / F value), for the purpose of Rukoto Kyosu Hisage good internal combustion engine with fuel economy.

But, the cylinder head having a plug mounting hole without the female threaded plug mounted, comprising a metal shell male screw plug attachment is not formed, a spark plug which is fixed is inserted into the plug mounting hole, the plug An internal combustion engine comprising: a spark plug assembly for securing the spark plug in the mounting hole; and the same part number as the spark plug having the same part number as the cylinder head having the same part number. In any combination of the plug fixtures, the swirl streamline passing through the center of the ring-shaped tip surface of the tip of the metal shell and the point of intersection of the tip when viewed from the axial tip of the spark plug Among them, one or a plurality of outer electrodes are arranged on the tip surface in the circumferential angle range, excluding the angle range of −30 to 30 degrees, of the tip surface, with the upstream intersection as a reference. Re also it is secured also preferable to an internal combustion engine according to claim.

According to an internal combustion engine of the above configuration, in any combination of the same part of the cylinder head and spark plug and plug fastener, fixation of the outer electrode, except -30 to 30 degrees, in the circumferential direction angle range It is fixed to the tip. Therefore, as can be seen from FIGS. 27 (b) and 28 (b), the fixed portion of the outer electrode does not hinder the swirl toward the discharge region between the center electrode and the outer electrode of the plug. The swirl can be reliably ignited. Therefore, in consideration of the case where the fixed portion of the outer electrode prevents the swirl, it is not necessary to drive the internal combustion engine with a rich air-fuel mixture, and the internal combustion engine can be driven with a thin air-fuel mixture (high A / F value). It can be improved further.

Also, a cylinder head provided with a plug mounting hole, and a spark plug assembly, a center electrode extending in the axial direction, surrounding the radial periphery of the center electrode, an insulator for fixing the center electrode, the A metal shell that surrounds the periphery of the insulator in the radial direction, fixes the insulator, and has a main body portion and a distal end portion that is smaller in diameter than the front end side main body portion of the main body portion and extends in the axial front end side; An ignition plug assembly comprising: an ignition plug including one or a plurality of outer electrodes fixed to a distal end surface of the distal end portion; and a plug fixing tool for fixing the ignition plug in the plug mounting hole; The plug mounting hole of the cylinder head includes a tip side body corresponding portion and a tip corresponding portion corresponding to the tip side main body portion and the tip portion of the spark plug, respectively. At least one of the front end side main body portion of the plug and the front end side main body corresponding portion of the plug mounting hole, and the front end portion of the spark plug and the front end corresponding portion of the plug mounting hole, while inserting the spark plug into the plug mounting hole. One or a plurality of outer electrode fixing portions centering on the shaft of the spark plug, the fitting position-restricting shape engaging each other only at one or a plurality of locations when rotated about the shaft When the ignition plug of the same product number is seen, the relationship between the circumferential direction angle and the front end side main body portion or the front end portion which is the fitting position restriction shape is substantially the same for any spark plug, When the cylinder head with the same part number is seen on the tip side body-corresponding part or the tip-corresponding part of the cylinder head that has a fitting position restriction shape, it is almost the same for all cylinder heads. The spark plug is fitted into the plug mounting hole of the cylinder head and fixed by the plug fixing tool. When viewed from the front end side in the axial direction of the spark plug, Out of the intersection of the swirl streamline passing through the center of the ring-shaped tip surface and the tip surface, the angle in the circumferential direction excluding the angle range of -30 to 30 degrees of the tip surface with respect to the upstream intersection It is also preferable that the internal combustion engine is characterized in that any one or a plurality of outer electrodes are fixed to the tip surface within the range.

According to an internal combustion engine of the above configuration, the spark plug and the cylinder head, the distal end side main body and the tip body corresponding portions, and since at least one of the tip and the tip corresponding portion is a fitting position restriction shape When the plug is inserted into the plug mounting hole, the fitting position is limited to one place or a plurality of places. Further, in the plug, the relationship between the outer electrode fixing portion and the distal end side main body portion or the distal end portion which is the fitting position restriction shape is substantially the same in any plug, and in the cylinder head, the fitting position restriction shape is provided. The cylinder head corresponding to the tip side body or the tip corresponding part of the cylinder head is substantially the same in any cylinder head. Accordingly, when the plug is inserted into the plug attachment hole after all, the relationship between the fitting positions of the two is limited, and therefore the circumferential angle of the outer electrode fixing portion is also limited to one or a plurality of locations. In addition, when viewed from the tip end side in the axial direction of the spark plug, the outer electrode has a tip end surface within a circumferential angle range excluding an angle range of −30 to 30 degrees out of the tip surface with reference to the swirl streamline. Both are fixed.

Therefore, in the internal combustion engine, the outer electrode fixing portion of the plug can be positioned at one or more specific circumferential angles even if the ignition plug of the same product number and the cylinder head of the same product number are arbitrarily combined. For this reason, the angle in the circumferential direction of the outer electrode fixing portion of the plug does not vary, and even an engine having a different plug and / or cylinder head can be driven under the condition of a uniform A / F value. Further, there is no need to drive the engine under operating conditions that take into account variations in the circumferential angle.
Further, when the plug is assembled to the engine, the outer electrode fixing portion is in a specific position appropriate to the swirl, that is, within a circumferential angle excluding a range of −30 to 30 degrees with respect to the swirl streamline. The position of the fitting position limiting shape and the outer electrode fixing portion are taken into consideration so as to be positioned at For this reason, in any combination of the spark plug of the same product number and the cylinder head of the same product number, it is possible to drive the internal combustion engine up to a thin air-fuel mixture without always restricting the flow of the swirl.

  Here, the fitting position restriction shape is when a rod (corresponding to the tip body portion or tip portion of the plug above) is inserted into a hole (corresponding to the tip body portion corresponding to the cylinder head or tip correspondence portion above). In addition, any shape may be used as long as the rods are fitted to each other only at one place or a plurality of places when the rod is rotated around the axis of the rod while being inserted into the hole. For example, specifically, a key groove extending in the axial direction is formed in the hole, and a key protrusion (which may be a strip or a protrusion) that fits in the key groove on the rod, or conversely, a key protrusion in the hole, A rod with a keyway, a chamfer on the rod, and a hole with a shape suitable for the rod, and a cross-sectional shape of the hole and rod each having an oval, elliptical, polygonal shape, etc. Etc.

  The spark plug assembly further includes a spark plug and a plug fixture for fixing the spark plug in a plug mounting hole formed in a cylinder head of the internal combustion engine, the spark plug having a shaft A central electrode extending in the direction, surrounding the radial circumference of the central electrode, fixing the central electrode, surrounding the radial circumference of the insulator, fixing the insulating body, A metal shell having a tip portion that is smaller in diameter than the tip side main body portion and extending toward the tip side in the axial direction, and one or more outer electrodes fixed to the tip surface of the tip portion. When at least one of the front end side main body portion and the front end portion of the spark plug rotates around the shaft while inserting the spark plug into the plug mounting hole, the front end side of the plug mounting hole The distal end side body corresponding portion and the distal end corresponding portion corresponding to the body portion and the distal end portion, respectively, have a fitting position limiting shape that fits only at one place or a plurality of places, with the shaft of the spark plug as the center The relationship between the circumferential angle of the one or more outer electrode adhering portions and the front end side main body portion or the front end portion having the fitting position limiting shape is any ignition when a spark plug of the same product number is viewed. It is preferable that the spark plug assembly is characterized in that the plugs are substantially the same.

According to the spark plug assembly having the above configuration, since at least one of the front end side main body portion and the front end portion of the plug has a fitting position limiting shape, the plug is fitted when the plug is inserted into the plug mounting hole. The position to perform is limited to one place or a plurality of places. On the other hand, since the relationship between the outer electrode fixing portion and the distal end side main body portion or the distal end portion having a fitting position-restricted shape is substantially constant in any plug, after all, the plug is inserted and fitted into the plug mounting hole. When combined, the fitting position relationship between the two is restricted (determined), so the position of the outer electrode fixing portion is also restricted to one place or a plurality of places.
Therefore, if a cylinder head suitable for this plug is used, the outer electrode fixing portion of the plug can be positioned at one or more specific circumferential angles when any of the spark plugs of the same product number is assembled to the engine. Can do. For this reason, the angle in the circumferential direction of the outer electrode fixing portion of the plug does not vary, and the engine can be driven under a uniform A / F value condition. Further, there is no need to drive the engine under operating conditions that take into account variations in the circumferential angle.
Further, when the plug is assembled to the engine, the fitting position restriction shape of the cylinder head and the plug and the position of the outer electrode fixing portion are set so that the outer electrode fixing portion is in an appropriate specific position in relation to the swirl. Considering this, the internal combustion engine can be driven to a thin air-fuel mixture without always restricting the flow of the swirl in any combination of the spark plug of the same product number and the cylinder head of the same product number.

  The plug sealing surface may be provided at the boundary between the distal end body portion and the distal end portion, and specifically, a flat sheet type in which the distal end side surface of the distal end side body portion is a plane perpendicular to the axis. Alternatively, it may be a conical sheet type in which the tip side surface of the tip side main body is tapered with respect to the axis. In the case of a flat sheet type, a gasket may be interposed between the sealing surface and the cylinder head.

In this spark plug assembly, the plug fixture includes an ignition transformer disposed so as to be positioned in the plug mounting hole when the spark plug is fixed, or an ignition circuit including an ignition transformer. A spark plug assembly is preferable.
In this spark plug assembly, since the plug fixture includes an ignition transformer having a predetermined arrangement or an ignition circuit including the ignition transformer, when the spark plug is fixed to the plug attachment hole using the plug fixture, the plug attachment hole is simultaneously provided. An ignition transformer or the like can be simultaneously disposed in the interior.
Therefore, it is not necessary to mount the ignition transformer or the like in the plug mounting hole separately from the plug mounting, and the assembly can be performed quickly and easily.
In addition, the ignition circuit including the ignition transformer or the ignition transformer is a source of noise because it generates a high voltage, but if it is placed in the plug mounting hole, the periphery is surrounded by a metal cylinder head. Noise emission can be reduced.

Furthermore, in any one of the above spark plug assemblies, the plug fixing tool may be a spark plug assembly characterized by including a mounting hole for fixing to the upper surface of the cylinder head.
In this spark plug assembly, since the plug fixing tool can be fixed to the cylinder head, it can be fixed on the upper surface of the plug. Therefore, as in the case of fastening a conventional plug, a plug wrench is inserted into the plug mounting hole. It is not necessary to tighten the screw of the plug, and the plug can be easily fixed or removed. Specifically, the plug fixing tool may be fixed to the upper surface of the head with a bolt passing through the mounting hole.

In any one of the above spark plug assemblies, the plug fixture extends in the axial direction and presses the spark plug main body portion toward the tip end side along the axial direction. A spark plug assembly including a cylindrical part for fixing may be used.
Since this spark plug assembly has a cylindrical portion, the main body portion of the plug can be pressed and fixed with this cylindrical portion, so that the spark plug can be pressed and fixed uniformly in the circumferential direction of the main body portion, and the seal can be surely sealed. can do.
In particular, it is more preferable that the cylindrical portion is made of metal and an ignition transformer and an ignition circuit are held in the cylindrical portion because the cylindrical portion also serves as a shield.
As the main body portion of the plug pressed by the cylindrical portion, the front end side main body portion may be used. This is because the plug can be stably pressed by pressing the tip as far as possible. On the other hand, you may make it press the crimping part of a base end side main-body part. This is because pressing the caulking portion can also prevent the caulking from loosening.

Alternatively, in any one of the spark plug assemblies described above, the spark plug includes a connection terminal on a proximal end side of the center electrode, and the plug fixing tool pivots the connection terminal when the spark plug is fixed. It is preferable that the spark plug assembly includes a pressing terminal that presses toward the leading end in the direction and guides a high voltage to the connection terminal.
In this spark plug assembly, the connecting terminal connected to the center electrode of the plug is pressed by the pressing terminal, so that the pressing of the spark plug and the electrical connection with the center electrode can be performed simultaneously.

  Further, a cylinder head including a plug mounting hole, the plug mounting hole includes a front end side body corresponding portion and a front end corresponding portion corresponding to the front end side main body portion and the front end portion of the metal shell of the spark plug, respectively. When at least one of the tip-side body-corresponding portion and the tip-corresponding portion is rotated about the axis of the spark plug while inserting the spark plug into the plug mounting hole, the tip-side main body portion or the tip of the spark plug And the tip-side body corresponding part or the tip-corresponding part that has the fitting position restriction shape is connected to the cylinder head of the same product number. When viewed, it is preferable that the cylinder head is characterized in that all cylinder heads are substantially the same.

In the cylinder head having the above configuration, at least one of the tip-side body-corresponding portion and the tip-corresponding portion of the plug mounting hole has a fitting position limiting shape, so that the tip-side body portion and tip portion corresponding to this shape Is inserted into the plug mounting hole, the fitting position is limited to one place or a plurality of places. On the other hand, the front-end-side body-corresponding portion and the tip-corresponding portion that are in the fitting position restriction shape are substantially the same in any cylinder head, so after all, when a plug corresponding to such a plug mounting hole is inserted Since the fitting position relationship between the two is restricted, the circumferential position of the plug is also restricted. Here, in the plug, the relationship between the circumferential angle of the outer electrode fixing portion and the distal end side main body portion or the distal end portion having the fitting position restriction shape is substantially the same for all plugs of the same product number. If the plug is defined in the plug mounting hole using a plug, the position of the outer electrode fixing portion of the plug can be limited to a specific location.
Therefore, the angle in the circumferential direction of the outer electrode fixing portion of the plug does not vary, and the engine can be driven under the condition of a uniform A / F value. Further, there is no need to drive the engine under operating conditions that take into account variations in the circumferential angle.
Further, when the plug is assembled to the engine, the fitting position restriction shape of the cylinder head and the plug and the position of the outer electrode fixing portion are set so that the outer electrode fixing portion is in an appropriate specific position in relation to the swirl. Considering this, the internal combustion engine can be driven to a thin air-fuel mixture without always restricting the flow of the swirl in any combination of the spark plug of the same product number and the cylinder head of the same product number.

  A central electrode extending in the axial direction; an insulator surrounding the radial circumference of the central electrode; fixing the central electrode; and surrounding the radial circumference of the insulator; fixing the insulator; A metal shell having a tip portion and a tip portion that is smaller in diameter than the tip side main body portion of the main body portion and extends toward the tip side in the axial direction, and one or more outer electrodes fixed to the tip surface of the tip portion. An ignition plug provided with at least one of the distal end side main body portion and the distal end portion when the ignition plug is rotated about the shaft while being inserted into a plug mounting hole formed in a cylinder head. The mounting hole has a fitting position limiting shape that fits only at one or a plurality of locations with the distal end body corresponding portion and the distal end corresponding portion corresponding to the distal end main body portion and the distal end portion of the mounting hole, respectively. The relationship between the circumferential direction angle of the one or more outer electrode fixing portions as the center and the front end side main body portion or the front end portion having the fitting position restriction shape is as follows. It is preferable that the spark plug is characterized by being substantially the same.

In the spark plug having the above-described configuration, since at least one of the front end side main body part and the front end part has a fitting position restriction shape, the front end side main body corresponding part corresponding to this shape and the cylinder head including the front end corresponding part are provided. When inserted into the plug mounting hole, the fitting position is limited to one place or a plurality of places. On the other hand, since the relationship between the outer electrode and the distal end side main body portion or the distal end portion having a fitting position restriction shape is substantially the same in any plug, the plug of the present technology is eventually inserted into the corresponding plug mounting hole. When inserted, the relationship between the fitting positions of the two is restricted, so the position of the outer electrode is also restricted at one place or a plurality of places.
Therefore, if a cylinder head suitable for this plug is used, the outer electrode fixing portion of the plug can be positioned at one or more specific circumferential angles when any of the spark plugs of the same product number is assembled to the engine. Can do. For this reason, the angle in the circumferential direction of the outer electrode fixing portion of the plug does not vary, and the engine can be driven under a uniform A / F value condition. Further, there is no need to drive the engine under operating conditions that take into account variations in the circumferential angle.
Further, when the plug is assembled to the engine, the fitting position restriction shape of the cylinder head and the plug and the position of the outer electrode fixing portion are set so that the outer electrode fixing portion is in an appropriate specific position in relation to the swirl. Considering this, the internal combustion engine can be driven to a thin air-fuel mixture without always restricting the flow of the swirl in any combination of the spark plug of the same product number and the cylinder head of the same product number.

  The plug sealing surface may be provided at the boundary between the distal end body portion and the distal end portion, and specifically, a flat sheet type in which the distal end side surface of the distal end side body portion is a plane perpendicular to the axis. Alternatively, it may be a conical sheet type in which the tip side surface of the tip side main body is tapered with respect to the axis. In the case of a flat sheet type, a gasket may be interposed between the sealing surface and the cylinder head.

  Furthermore, a plug fixture for pressing and fixing an ignition plug inserted in a plug mounting hole formed in a cylinder head of an internal combustion engine in an axial direction, the plug having an ignition circuit including an ignition transformer or an ignition transformer A fixture is preferred.

Since this plug fixture includes an ignition transformer or an ignition circuit including the ignition transformer, when the spark plug is fixed to the plug mounting hole using the plug fixture, the ignition transformer or the like can be disposed at the same time.
Therefore, it is not necessary to mount the ignition transformer or the like in the plug mounting hole separately from the plug mounting, and the assembly can be performed quickly and easily.
Here, in this plug fixture, the ignition transformer including the ignition transformer or the ignition transformer is preferably arranged so as to be positioned in the plug mounting hole.
An ignition transformer or an ignition circuit including an ignition transformer is a source of noise because it generates a high voltage. However, if it is placed in the plug mounting hole, the surroundings are surrounded by a metal cylinder head, so noise This is because radiation can be reduced.

  Furthermore, in the plug fixing tool described above, it is preferable that the plug fixing tool is provided with a mounting hole for being fixed to the upper surface of the cylinder head. When this plug fixture is used, the plug fixture itself can be secured to the cylinder head, so that it can be secured on the top surface of the plug, so a plug wrench can be installed inside the plug mounting hole as in the case of fastening a conventional plug. There is no need to insert and tighten the screw of the plug, and the plug can be easily fixed or removed. Specifically, the plug fixing tool may be fixed to the upper surface of the head with a bolt passing through the mounting hole.

Further, the plug fixing tool includes a cylindrical portion for pressing the main body portion of the metal shell of the ignition plug toward the tip end side in the axial direction of the ignition plug and fixing the ignition plug. It may be a featured plug fixture.
Since this plug fixture has a cylindrical part, the main part of the plug can be pressed and fixed by this cylindrical part, so that the spark plug can be fixed by pressing uniformly in the circumferential direction of the main part and reliably sealed. be able to.
In particular, it is more preferable that the cylindrical portion is made of metal and an ignition transformer and an ignition circuit are held in the cylindrical portion because the cylindrical portion also serves as a shield.
As the main body portion of the plug pressed by the cylindrical portion, the front end side main body portion may be used. This is because the plug can be stably pressed by pressing the tip as far as possible. On the other hand, you may make it press the crimping part of a base end side main-body part. This is because pressing the caulking portion can also prevent the caulking from loosening.

Further, these plug fixtures press the connection terminal toward the distal end side in the axial direction of the spark plug when the spark plug having the connection terminal on the proximal end side of the center electrode is fixed, and high voltage is applied to the connection terminal. It is preferable that the plug fixing tool is provided with a pressing terminal for guiding to the plug.
Since the plug fixing device includes a pressing terminal that presses the connection terminal connected to the center electrode of the plug, when the plug is fixed in the plug mounting hole using the plug fixing device, the pressing of the ignition plug and the center electrode Electrical connection can be made at the same time.

The solving means is an internal combustion engine including a cylinder head having a plug mounting hole and a spark plug assembly, the spark plug assembly having a center electrode extending in the axial direction and a radial periphery of the center electrode. An insulator that fixes the center electrode, and surrounds the periphery of the insulator in the radial direction, the insulator is fixed, and a main body portion having a proximal-side body portion and a distal-side body portion and the distal-end side A spark plug having a metal shell having a tip portion smaller in diameter than the main body portion and extending toward the tip end in the axial direction, and one or a plurality of outer electrodes fixed to the tip surface of the tip portion; and a substantially cylindrical shape None, having a cylindrical part that fits into the base end side main body part and contacts the main body part when the base end side of the spark plug is inserted therein, and presses the main body part in the axial direction The ignition plug is inserted into the plug mounting hole by A base end side main body portion of the spark plug and a cylindrical portion of the plug fixture, and a base end side of the spark plug is connected to the cylindrical portion of the plug fixture. 1 or a plurality of positions around the shaft of the spark plug. The relationship between the circumferential direction angle of the outer electrode fixing portion and the base end side main body portion having the fitting position limiting shape is substantially the same for any spark plug when the spark plug of the same part number is viewed. When the plug part having the same part number is seen in the fitting part restricting shape, the tubular part is substantially the same for all the plug parts, and the base end body part is fixed to the plug. Fitting to the cylindrical part of the tool, the main body part is the cylindrical part The spark plug is pressed and fixed in the plug mounting hole, and a swirl streamline passing through the center of the ring-shaped tip surface of the tip of the metal shell when viewed from the tip end side in the axial direction of the spark plug One or a plurality of outer sides of the tip surface within the circumferential angle range, excluding an angle range of −30 to 30 degrees, of the tip surface, with reference to the upstream intersection, An internal combustion engine characterized in that all of the electrodes are fixed.

  According to the internal combustion engine of the present invention having the above-described configuration, the tubular portion of the plug fixture and the base end side main body portion of the spark plug have a fitting position limiting shape. When it is inserted into the tubular part of the fixture, the fitting position is limited to one place or a plurality of places. Further, in the plug, the relationship between the outer electrode fixing portion and the base end side main body portion which is the fitting position limiting shape is substantially the same in any plug, and in the plug fixture, the fitting position limiting shape is The cylindrical portion of the plug fixing tool made is substantially the same in any plug fixing tool. Therefore, after all, when the plug is inserted and fitted into the cylindrical portion, the fitting positional relationship between the two is restricted, and therefore the circumferential angle of the outer electrode fixing portion is also restricted to one place or a plurality of places. In addition, when viewed from the tip end side in the axial direction of the spark plug, the outer electrode has a tip end surface within a circumferential angle range excluding an angle range of −30 to 30 degrees out of the tip surface with reference to the swirl streamline. Both are fixed.

Therefore, in an internal combustion engine, even if an ignition plug of the same product number and a plug fixture of the same product number are arbitrarily combined, if the plug fixture is attached at a predetermined position, the outer electrode fixing portion of the plug is one or more specific locations. Can be positioned at a circumferential angle. For this reason, the angle in the circumferential direction of the outer electrode fixing portion of the plug does not vary, and even an engine having a different plug and / or cylinder head can be driven under the condition of a uniform A / F value. Further, there is no need to drive the engine under operating conditions that take into account variations in the circumferential angle.
Further, when the plug is assembled to the engine, the outer electrode fixing portion is in a specific position appropriate for the swirl, that is, a circumferential angle range excluding a range of −30 to 30 degrees with respect to the swirl streamline. The position of the fitting position limiting shape and the outer electrode fixing portion is taken into consideration so as to be located inside. For this reason, in any combination of spark plugs of the same product number and plug fixtures of the same product number, the circumferential position of the outer electrode fixing portion can be restricted to a specific location, so that the flow of the swirl is not always restricted, and the thin air-fuel mixture The internal combustion engine can be driven up to.
Moreover, since the main part of the plug is pressed by the cylindrical part, the plug can be pressed uniformly in the circumferential direction and can be reliably sealed.

  A spark plug assembly further comprising a spark plug and a plug fixture for fixing the spark plug in a plug mounting hole formed in a cylinder head of the internal combustion engine, wherein the center electrode extends in the axial direction. An insulator surrounding the center electrode in the radial direction and fixing the center electrode; and surrounding the insulator in the radial direction and fixing the insulator; A metal shell having a main body portion having a portion, a tip portion having a smaller diameter than the tip side main body portion and extending in the axial tip side, and one or a plurality of outer electrodes fixed to the tip surface of the tip portion. A spark plug having a substantially cylindrical shape, and having a cylindrical portion that fits and contacts the main body when the base end of the spark plug is inserted therein, By pressing the main body in the axial direction, A plug fixing tool for fixing the fire plug, and when the base end side of the spark plug is inserted into the tubular portion of the plug fixing tool and rotated around the axis, the base end side of the spark plug The main body portion and the tubular portion of the plug fixing tool have a fitting position limiting shape that can be fitted to each other only at one place or a plurality of places, and the one or more around the shaft of the spark plug. The relationship between the circumferential direction angle of the outer electrode fixing portion and the base end side main body portion having the fitting position limiting shape is substantially the same for any spark plug when the spark plug of the same part number is viewed. The spark plug assembly is characterized in that when the plug part having the same part number is seen, the plug part is substantially the same when the cylindrical part having the fitting position restriction shape is seen. Is preferable.

In the spark plug assembly having the above-described configuration, the tubular portion of the plug fixture and the base end side main body portion of the spark plug have a fitting position-restricted shape. When fitted, the fitting position is limited to one or a plurality of places. On the other hand, the relationship between the outer electrode fixing portion and the base end side main body portion having a fitting position limiting shape is substantially constant in any plug, so that the plug is inserted into the tubular portion of the plug fixture after all. -Since the fitting position relationship between the two is restricted (determined) when fitted, the position of the outer electrode fixing portion is also restricted to one place or a plurality of places.
Therefore, if the plug fixing tool is attached to a predetermined position of the engine (for example, a cylinder head) to fix the plug in the plug mounting hole, the outer electrode fixing portion of the plug is positioned at one or more specific circumferential angles. Can be made. For this reason, the angle in the circumferential direction of the outer electrode fixing portion of the plug does not vary, and the engine can be driven under a uniform A / F value condition. Further, there is no need to drive the engine under operating conditions that take into account variations in the circumferential angle.
Furthermore, when the plug is assembled to the engine, the fitting position limiting shape of the plug fixing tool and the plug and the position of the outer electrode fixing portion so that the outer electrode fixing portion is in an appropriate specific position in relation to the swirl. Take into account. Then, in any combination of spark plugs of the same product number and plug fixtures of the same product number, the circumferential position of the outer electrode fixing part can be restricted to a specific location, so the flow of the swirl is not always restricted, and even to a thin mixture An internal combustion engine can be driven.
Moreover, since the main part of the plug is pressed by the cylindrical part, the plug can be pressed uniformly in the circumferential direction and can be reliably sealed.

Moreover, since the position of the outer electrode fixing portion can be determined by the radial cross-sectional shape of the plug fixing tool and the plug, the plug mounting hole formed in the cylinder head does not need to be deformed such as forming a key groove, and is simple. Can be composed of only a simple cylinder, or a cylinder and a taper. Accordingly, the cylinder head can be easily formed and processed.
The plug sealing surface may be provided in the vicinity of the boundary between the distal end side main body portion and the distal end portion. Specifically, the flat sheet has a surface perpendicular to the axis on the distal end side surface of the distal end side main body portion. Alternatively, a conical sheet mold may be used in which the tip side surface of the tip side main body is tapered with respect to the axis. In the case of a flat sheet type, a gasket may be interposed between the sealing surface and the cylinder head.
Specific examples of the fitting position limiting shape include a key groove and a key protrusion (which may be a strip or a protrusion), chamfering, an oval shape, an oval shape, a polygonal shape, and the like.

Further, in this spark plug assembly, the spark plug has a non-rotationally symmetric shape about the axis when the distal end direction is viewed from the axial base end side. An assembly is recommended.
In this spark plug assembly, when the distal end direction is viewed from the axial base end side, the plug fixture is in a non-rotation symmetric shape, so when inserting the plug into the tubular portion of the plug fixture, Since the plug can be inserted with the circumferential angle of the plug fixture fixed, the base end side main body portion of the plug can be easily fitted to the cylindrical portion.
Further, when the plug is fixed to the plug mounting hole, the orientation of the plug fixing tool can be determined when the plug fixing tool is viewed from the axial base end side, that is, from above the plug mounting hole. Therefore, the direction of the outer electrode fixing portion in the plug fitted to the tubular portion of the plug fixture can also be determined and determined.
Conversely, when the plug assembly (plug and plug fixture) is attached, the plug fixture is not attached in the wrong direction.

Alternatively, in the spark plug assembly, the plug fixture includes a mounting hole for fixing to the top surface of the cylinder head, and the mounting hole is non-rotationally symmetric when the axis is the center. The spark plug assembly is preferably arranged.
In this spark plug assembly, since the mounting holes of the plug fixing tool are arranged in a non-rotationally symmetrical manner, the direction of the plug fixing tool can be determined when fixing the plug to the plug mounting hole. The direction of the outer electrode fixing portion in the plug fitted to the tubular portion of the plug fixture can also be determined and determined.
Conversely, when attaching the plug and the plug fixing tool, the plug fixing tool is not attached in the wrong direction.
In particular, since the mounting hole of the plug fixture is arranged in a non-rotationally symmetric shape with the axis as the center, when attaching to the cylinder head, the plug fixture cannot be installed unless it is in a predetermined orientation. The orientation of the plug fixing part is determined. Therefore, the direction of the outer electrode fixing portion of the plug fitted to the plug fixture is also automatically determined. In addition, if you try to install it incorrectly, it will not fit into the plug, the cylindrical part cannot be inserted into the plug mounting hole, or the position of the plug mounting hole will be incompatible. Can be installed in the correct orientation for sure.

  Further, a central electrode extending in the axial direction, an insulator surrounding the radial direction of the central electrode and fixing the central electrode, and surrounding the radial periphery of the insulator and fixing the insulator, A metal shell having a main body portion having an end-side main body portion and a front-end-side main body portion, a tip portion having a diameter smaller than that of the front-end-side main body portion and extending in the axial direction, and fixed to the front end surface of the front end portion A spark plug having one or a plurality of outer electrodes, having a substantially cylindrical shape, extending in the axial direction, and having the base end side of the spark plug inserted therein, Is fitted with a cylindrical portion that contacts the main body, and the spark plug base is mounted on the cylindrical portion of the plug fixture for fixing the spark plug in the plug mounting hole formed in the cylinder head. When rotating around the axis while inserting the end side In addition, the base end side main body portion of the spark plug has a fitting position limiting shape that fits with the cylindrical portion only at one place or a plurality of places, and the 1 centered on the axis of the spark plug. Or, when the relationship between the circumferential direction angle of the plurality of outer electrode fixing portions and the base end side main body portion having the fitting position restriction shape is the same for the spark plug of the same part number, it is substantially omitted for any spark plug. It is preferable that the spark plug is characterized by being the same.

In the spark plug having the above configuration, since the radial cross-sectional shape of the base end side main body portion is a fitting position limiting shape, the plug fixing tool having a cylindrical portion that matches this shape is connected to the plug base end side. Is inserted, the fitting position is limited to one place or a plurality of places. On the other hand, since the relationship between the outer electrode and the base end side main body portion having the fitting-position-restricted shape is substantially the same for any plug, after all, the plug of the present technology is inserted into such a plug fixture. In this case, the direction (position) of the outer electrode fixing portion is also limited to one place or a plurality of places in relation to the plug fixture.

Therefore, when the plug fixing device is attached to the engine (for example, the cylinder head) in order to fix the plug in the plug mounting hole, the plug fixing device is correctly attached, that is, if the plug fixing device is attached in a predetermined position, The outer electrode fixing portion can be positioned at a specific one or a plurality of circumferential angles. For this reason, the angle in the circumferential direction of the outer electrode fixing portion of the plug does not vary, and the engine can be driven under a uniform A / F value condition. Further, there is no need to drive the engine under operating conditions that take into account variations in the circumferential angle.
Furthermore, when the plug is assembled to the engine, the fitting position limiting shape of the plug fixing tool and the plug and the position of the outer electrode fixing portion so that the outer electrode fixing portion is in an appropriate specific position in relation to the swirl. Take into account. Then, even if any of the spark plugs of the same product number is used, the circumferential position of the outer electrode adhering portion can be restricted to a specific place, so that the swirl flow is not always restricted and the internal combustion engine is driven to a thin air-fuel mixture. Can do.

  Further, the plug fixing tool for fixing the spark plug in the plug mounting hole formed in the cylinder head of the internal combustion engine, which has a substantially cylindrical shape, and the base end side of the spark plug is inserted into the plug fixing hole. When rotated about the central axis of the spark plug, the base end of the main body of the spark plug has a fitting position limiting shape that fits only at one or a plurality of locations. When the cylindrical part which has a cylindrical part which contacts a side body part, and was made into the above-mentioned fitting position restriction shape sees the plug fixture of the same product number, it is made almost the same about any plug fixture. It is preferable that the plug fixing tool is characterized in that

Since this plug fixture includes a cylindrical portion that is in a fitting position-restricted shape that fits only at one or a plurality of locations with the base end side main body portion of the plug, the base end side main body portion that conforms to this shape is provided. When the proximal end side of the provided plug is inserted into the cylindrical portion, the fitting position is limited to one place or a plurality of places.
Therefore, in order to fix the plug in the plug mounting hole, when the plug fixing tool is attached to the engine (for example, the cylinder head), the plug fixing tool is correctly attached, that is, if the plug fixing tool is attached in a predetermined position, the cylindrical shape The plug fitted in the portion can also be positioned at a specific circumferential angle at one or a plurality of locations.
Here, if the relationship between the outer electrode of the plug and the base end side main body portion having a fitting position-restricted shape is substantially constant in any plug, the plug will eventually be plugged into the tubular portion of the plug fixture of the present technology. Is inserted, the orientation (position) of the outer electrode fixing portion is also limited to one or a plurality of locations in relation to the plug fixture.

Therefore, when such a plug fixing tool is used, when the plug is assembled to the engine, the outer electrode fixing portion of the plug can be positioned at one or more specific circumferential angles. For this reason, the angle in the circumferential direction of the outer electrode fixing portion of the plug does not vary, and the engine can be driven under a uniform A / F value condition. Further, there is no need to drive the engine under operating conditions that take into account variations in the circumferential angle.
Furthermore, when the plug is assembled to the engine, the fitting position limiting shape of the plug fixing tool and the plug and the position of the outer electrode fixing portion so that the outer electrode fixing portion is in an appropriate specific position in relation to the swirl. Take into account. Then, even if any of the spark plugs of the same product number is used, the circumferential position of the outer electrode adhering portion can be restricted to a specific place, so that the swirl flow is not always restricted and the internal combustion engine is driven to a thin air-fuel mixture. Can do.

Further, this plug fixture may be a plug fixture having a non-rotationally symmetric shape about the axis when viewed from the axial base end side in the distal direction.
In this plug fixture, the plug fixture has a non-rotationally symmetric shape when viewed from the proximal end side in the axial direction to the distal direction. Therefore, when the plug is inserted into the tubular portion of the plug fixture, Since the plug can be inserted with the circumferential angle of the fixture fixed, the base end main body portion of the plug can be easily fitted to the cylindrical portion.
Further, when the plug is fixed to the plug mounting hole, the orientation of the plug fixing tool can be determined when the plug fixing tool is viewed from the axial base end side, that is, from above the plug mounting hole. Therefore, the direction of the outer electrode fixing portion in the plug fitted to the tubular portion of the plug fixture can also be determined and determined.
Conversely, when attaching the plug and the plug fixing tool, the plug fixing tool is not attached in the wrong direction.

Alternatively, the plug fixture includes an attachment hole for fixing to the upper surface of the cylinder head, and the attachment hole is arranged in a non-rotationally symmetrical manner with the axis as the center. It is better to use a plug fixing tool.
In this plug fixture, since the plug mounting holes are arranged in a non-rotationally symmetrical manner, the orientation of the plug fixture can be determined when the plug is fixed to the plug mounting hole. The direction of the outer electrode fixing portion in the plug fitted to the tubular portion of the plug fixture can also be determined and determined.
Conversely, when attaching the plug and the plug fixing tool, the plug fixing tool is not attached in the wrong direction.
In particular, since the mounting hole of the plug fixture is positioned in a non-rotationally symmetric shape with the axis as the center, it cannot be installed unless the plug fixture is in a predetermined orientation when mounting to the cylinder head. The orientation of the plug fixing part is determined. Therefore, the direction of the outer electrode fixing portion of the plug fitted to the plug fixture is also automatically determined. In addition, if you try to install it incorrectly, it will not fit into the plug, the cylindrical part cannot be inserted into the plug mounting hole, or the position of the plug mounting hole will be incompatible. Can be installed in the correct orientation for sure.

Further, in the spark plug manufacturing method, in the step of welding the outer electrode to the front end portion of the metal shell, a projection is welded to the main body portion or the front end portion of the metal shell, in tandem with the welding of the outer electrode. The spark plug manufacturing method is characterized in that the positional relationship between the outer electrode fixing portion and the protrusion is fixed, and the outer electrode and the protrusion are welded to the metal shell.
In this spark plug manufacturing method, since the protrusion is welded to the main body or the tip part before and after the welding of the outer electrode, the metallic shell is made with the positional relationship between the outer electrode fixing part and the protrusion always constant. be able to. For this reason, even in the completed plug, the relationship between the protrusion and the outer electrode fixing portion is always constant. Therefore, by combining a cylinder head or plug fixture with a plug mounting hole or a cylindrical portion in which a keyway suitable for this protrusion is formed, it is possible to easily limit the circumferential angle of the outer electrode fixing portion. it can.

( Reference form 1)
A first reference embodiment will be described with reference to the drawings.
Figure 1 is a partially cutaway sectional view and a bottom view of the spark plug 10 according to this preferred embodiment. The spark plug 10 is a so-called one-pole type in which only one outer electrode 16 is formed, and is sealed by a plug seat surface 14s that forms a plane provided between the main body 12 and the tip 13 of the metal shell 11. Is a so-called flat sheet type.
The plug 10 includes a center electrode 17 extending in the vertical direction (axial direction) in the figure, an insulator (insulator) 18 surrounding the periphery, and a metal shell 11 that holds the lower part in the figure. 11 is an axially distal end side (lower in the figure) having a diameter smaller than that of the main body part 12 including an upper proximal end main body part 13 and a lower distal end side body part 14 in the figure and a distal end side body part 14. And a tip portion 15 extending in the direction. Unlike the normal spark plug, the distal end portion 15 is not formed with a male screw and has an outer peripheral surface that is substantially cylindrical. The outer electrode 16 is fixed to the distal end surface 15a of the distal end portion 15 by the fixing portion 16a. The tip of the outer electrode 16 extends toward the center of the ring-shaped tip surface 15a as shown in FIG. 1 (b), and is bent into a substantially L shape as shown in FIG. 1 (a). A predetermined discharge gap is formed with the electrode 17.
Further, a ring-shaped gasket 19 is attached to the plug seat surface 14s, and a connection terminal 9 connected to the center electrode 17 is disposed at the base end (upper end in the figure).

Further, the base end side main body portion 13 is located on the base end side (upper side in the drawing) than the base end side main body central portion 13b having a slightly larger diameter and the internal structure, and is an insulator. A caulking portion 13 a that prevents the 18 from being pulled upward is provided, and similarly, a second caulking portion 13 c that is located on the distal end side and fixes the insulator 18 is provided. Further, a protrusion 14t is provided at one of the side surfaces 14b of the distal end side main body portion 14.
For this reason, as will be described later, the distal end side main body portion 14 is provided with a distal end side main body corresponding portion 34 provided with a key groove 36 adapted to the projection 14t in the plug mounting hole 32 formed in the cylinder head 30, and in the circumferential direction. It can be fitted only at one place.

Moreover, the plug 10 of the present reference embodiment, the position of the protrusion 14t, and the position of the fixing portion 16a of the outer electrode 16 which is secured to the distal end surface 15a, are to have a predetermined relationship. The relationship will be described below with reference to FIG. FIG. 2 is a bottom view of the spark plug shown in FIG. 1B. The insulator 18, the tip surface 15 a, and the tip side main body 14 are centered on an axis O passing through the center electrode 17 of the plug. Appear concentrically. Here, when the angle ψ is measured counterclockwise with OT connecting the axis (center) O and the protrusion 14t (this center being T) as a reference (horizontal axis in the figure), the outer electrode The circumferential angle ψ1 (= TOA) of the fixing portion 16a (this center is A) is ψ1 = 180 degrees as shown in FIG. The angle ψ may be another angle ψ2, as indicated by a broken line in FIG. 2, but the range of UOU ′, that is, the range of ψ = ± 30 degrees with respect to the reference line OT. It is good to be outside, that is, in the range of ψ = + 30 to +330. This angle (± 30 degrees) is based on the graph shown in FIG. 27B, and details will be described later.

Next, the cylinder head 30 according to this preferred embodiment will be described with reference to FIG. The head main body 31 of the cylinder head 30 includes a plug mounting hole 32 penetrating between the head upper surface 31a and the combustion chamber surface 31b, and further, a plug mounting tool 20 described later is screwed to the surrounding head upper surface 31a. Screw holes 37a to 37d are formed. The plug mounting hole 32 has a depth that allows the above-described spark plug 10 to be completely inserted, and is composed of a three-stage round hole that gradually decreases in diameter from the head upper surface 31a.

Among these, the insertion portion 33 on the head upper surface 31a side is a deeply dug circular hole extending from the head upper surface 31a to the vicinity of the combustion chamber surface 31b. Since the diameter is also large, the plug 10 can be easily inserted as will be described later. In this example, the insertion portion 33 has a cylindrical shape, but the diameter may gradually increase toward the head upper surface 31a. Moreover, the front end corresponding | compatible part 35 by the side of the combustion chamber surface 31b is a part by which the front-end | tip part 15 is inserted in loose fitting when the said ignition plug 10 is inserted.
Moreover, the front end side main body corresponding portion 34 positioned between the insertion portion 33 and the front end corresponding portion 35 is a portion into which the front end side main body portion 14 is inserted loosely when the spark plug 10 is inserted. Here, as will be described later, the seal surface 34a that hits the boundary between the distal end side main body corresponding portion 34 and the distal end corresponding portion 35 is a surface on which the gasket 19 of the plug 10 abuts and seals. Further, as can be seen from FIG. 3A, a key groove 36 is formed in the distal end side main body corresponding portion 34 with a width and a depth suitable for the protrusion 14t of the plug 10.
The cylinder head 31 is formed with a circulation hole 38 for circulating cooling water.

Next, the plug fastener 20 according to this preferred embodiment will be described with reference to FIG. The fixture main body 21 of the plug fixture 20 is made of metal and includes a flange portion 23 for fixing the plug fixture 20 to the cylinder head 30 and a cylindrical portion 22 having a substantially cylindrical shape. As shown in FIG. 4A, attachment holes 27a to 27d are formed in the flange portion 23 at positions corresponding to the screw holes 37a to 37d of the cylinder head 30, respectively. In addition, the outer peripheral surface 22b of the cylindrical portion 22 is slightly smaller in diameter than the insertion portion 33 of the cylinder head 30, and the front end surface 22a of the front end (lower end in the figure) is as described later. In order to be able to press the upper surface 14 a of the distal end side main body portion 14 of the plug 10, the inner peripheral surface 22 c is made larger in diameter than the proximal end side main body portion 13.

Further, as shown in FIG. 4B, an insulator holding member made of heat-resistant rubber and holding the insulator 18 when the proximal end side of the plug 10 is inserted inside the cylindrical portion 22. 24, an elastic terminal 25 elastically connected to the connection terminal 9 is formed.
Further, although not shown in detail, an ignition transformer 26 that generates a high voltage by a low-voltage primary coil current sent through a cable 28 that passes through the flange portion 23 is also incorporated. The high voltage generated in the ignition transformer 26 is applied directly from the elastic terminal 25 to the connection terminal of the spark plug 10. For this reason, a high withstand voltage cable (high tension cable) is unnecessary, and noise generation is reduced. In particular, in this preferred embodiment, the ignition transformer 26, so is surrounded by a metallic fixture body 21, because the shield has been noise is hardly leaks to the outside can be further reduced noise. Further, since the ignition transformer 26 is built in, the plug 10 can be fixed in the plug mounting hole 32 by the plug fixture 20 as will be described later, and at the same time, the ignition transformer 26 can be disposed in the plug mounting hole 32. In addition, the connection between the plug 10 and the ignition circuit including the ignition transformer 26 can be completed.
Incidentally, according to the reference embodiment has been built only ignition transformer 26, in addition to the ignition transformer, may be built-in part or all of the ignition circuit such as a switching element or a capacitor such as a transistor.

  Next, the plug 10 and the plug fixture 20 are assembled to the cylinder head 30. Note that the cylinder head 30 is fastened to the engine block by a known method. First, as shown in FIG. 5, the plug 10 is inserted into the plug mounting hole 32 of the cylinder head 30. At this time, as described above, since the protrusion 14t is formed on the distal end side main body portion 14 of the plug 10, it is not normally completely fitted. Therefore, the plug 10 is rotated around the axis O. Then, when the protruding portion 14t is positioned in the key groove 36 formed in the distal end side main body corresponding portion 34, for example, when the protruding portion 14t is positioned on the right side in the drawing in FIG. The plug 10 is fitted to the cylinder head 30. That is, in the plug 10, the position (angle) at which the front end side main body portion 14 of the plug 10 and the front end side main body corresponding portion 34 of the plug mounting hole 32 are fitted to each other by the protrusion 14 t and the key groove 36 is 360 degrees in one round. Are limited to one place. As a result, the gasket 19 comes into contact with the seal surface 34a.

  Furthermore, the plug 10 is fixed using the plug fixing tool 20 described above. First, as shown in FIG. 6, the tubular portion 22 of the plug fixture 20 is inserted into the plug mounting hole 32. Since the outer peripheral surface 22 b of the cylindrical portion 22 is slightly smaller in diameter than the insertion portion 33, it can be inserted in a loose fit, and the distal end surface 22 a of the cylindrical portion 22 is the upper surface of the distal end side main body portion 14 of the plug 10. 14a abuts. At this time, the insulator 18 on the proximal end side of the plug 10 is inserted and held in the center of the insulator holding member 24 inside the cylindrical portion 22, and the connection terminal 9 is connected to the elastic terminal 25. .

Next, as shown in FIGS. 3 and 4, the direction of the flange portion 23 of the plug fixture 20 is adjusted so that the mounting holes 27a to 27d fit the screw holes 37a to 37d, and bolts BLa to BLd are used. Then, the plug fixture 20 is fixed to the head upper surface 31 a of the cylinder head 30. Thereby, the front end side main body portion 14 of the plug 10 is pressed by the front end surface 22a through the cylindrical portion 22, and a seal between the gasket 19, the seal surface 14s, and the stepped portion 34a can be performed. At this time, since the distal end side main body portion 14 is uniformly pressed in the circumferential direction by the cylindrical portion 22, the sealing can be surely performed.
Note that the length (height) of the cylindrical portion 22 is preferably adjusted in consideration of the dimensions of the plug 10 and the plug mounting hole 32 so that they can be pressed with an appropriate pressure. Further, as the gasket 19, a gasket formed by bending a so-called S-shaped gasket having a crushing margin may be used. This is because even if there is a dimensional error or the like of the plug 10 or the plug mounting hole 32, the error can be absorbed by the crushing allowance and the sealing can be surely performed.

In this way, the relationship between the swirl M2 and the outer electrode 16 in the state where the plug 10 is assembled to the engine 50 including the cylinder head 30 is as follows. That is, as shown in FIG. 7A, in the engine 50 including the piston 54 that moves up and down along the axial direction of the cylinder 53, the air-fuel mixture that has entered the combustion chamber 55 from the intake valve 51 becomes the swirl M2. Consider the case where it flows as shown. In addition, description of the plug fixing tool 20 was abbreviate | omitted in Fig.7 (a).
Here, as shown in FIG. 7B, when viewed from the distal end side (downward in the figure) of the plug 10, the swirl M2 is on the streamline Lm (or the streamline Lm) passing through the central axis O of the plug 10. If the key groove 36 is formed so that the center T of the protrusion 14t is positioned on the extension), the reference line OT and the stream line Lm overlap. Therefore, as described with reference to FIG. 2, the center A of the outer electrode fixing portion 16a of the plug 10 is located at a position where ψ1 = 180 degrees from the reference line OT. The circumferential angle θ1 (= SOA) of the fixed portion 16a as a reference is also θ1 = ψ1 = 180 degrees.

  By the way, in the case of a one-pole plug, as shown in the graph of FIG. 27B, with reference to the streamline Lm of the swirl M2, the circumferential angle θ to the outer electrode fixing portion is ± 30 degrees. The engine could be driven with a thin air-fuel mixture in the range excluding the range. Therefore, even in the case of θ1 = 180 degrees in this example, the engine 50 can be driven with a thin air-fuel mixture. This is because the outer electrode fixing portion 16a does not hinder the flow of the swirl M2, so that the swirl M2 can be reliably ignited by the discharge in the discharge region between the outer electrode 16 and the center electrode 17. For this reason, the engine 50 can always be driven to a thin air-fuel mixture with any combination of the plug 10 and the cylinder head 30 having the same product number, and the fuel efficiency can be improved.

Here, the position of the fixing portion 16a, that is, the position of the center A of the fixing unit, as in this preferred embodiment, it is apparent may not be .theta.1 = 180 degrees. That is, for example, as in the case of θ2 and θ3 shown in FIG. 7B, a circumferential angle range excluding a range of ± 30 degrees around the streamline Lm, that is, outside the range indicated by U1-O-U2. If the outer electrode fixing portion 16a is located on the front end surface 15a, the engine 50 can be similarly driven with a thin air-fuel mixture.
Therefore, for example, when the position of the key groove 36 is the same as described above, the protrusion 14t is fitted in the key groove 36. Therefore, in the plug 10, the protrusion 14t (center T) and the outer electrode fixing portion The angle TOA formed by 16a (center A) may be an angle outside the range of ± 30 degrees.
Further, the key groove 36 of the cylinder head 30 may be formed at a position rotated about the axis O as compared with FIG. Even in this case, the outer electrode fixing portion 16a may be positioned in the circumferential angle range excluding the range of ± 30 degrees with the streamline Lm as the center.

( Reference form 2)
Next, a reference form in which the shape of the plug fixture 20 is slightly changed to change the pressing position of the plug 10 will be described. In the present reference embodiment, the shapes of the plug 10 and the cylinder head 30 are not changed as compared with the first reference embodiment. Therefore, the description is omitted, and the plug fixing tool 220 is different from the plug fixing tool 20 of the first reference embodiment. Only the part is explained.
As shown in FIG. 8 (a), in the fixing device main body 221 of the plug fastener 220 of this preferred embodiment, the distal end portion 222A of the tubular portion 222, bent inward, the pressing surface 222a of the front inner corner portion However, it is a concave surface having a substantially ¼ arc shape adapted to the shape of the caulking portion 13 a of the plug 10.
Therefore, in the same manner as in Reference Embodiment 1, when fixing the plug 10, the pressing surface 222a of the cylindrical portion 222, rather than the top surface 14a of the tip body portion 14 (see FIG. 6 (a)), base body part The 13 crimping portions 13a are pressed toward the tip end side in the axial direction (downward in the figure). Due to the explosion in the combustion chamber 55, pressure is applied to the crimping portion 13a in the direction in which the insulator 18 is pulled out to the axial base end side (upward in the figure), and a force in the direction in which the crimping is loosened is applied. On the other hand, in this reference embodiment, since the crimping part 13a is pressed by the pressing surface 222a, loosening of the crimping part 13a can also be prevented.

( Reference form 3)
Then, by slightly changing the shape of the plug fastener 20 of Reference Embodiment 1, a description will be given of another reference embodiment by changing the pressing position of the plug 10. Also in this reference embodiment, the shapes of the plug 10 and the cylinder head 30 are not changed compared to the reference embodiment 1, and thus the description thereof is omitted, and the plug fixing device 320 is different from the plug fixing device 20 of the reference embodiment 1. Only the part is explained.
As shown in FIG. 8 (b), in the fixture main body 321 of the plug fixture 320 of the present reference embodiment, the tubular portion 22 is not formed unlike the reference embodiment 1, and the plug fixture using bolts BLa to 32d. Only the flange portion 323 for fixing 320 to the cylinder head 30 is provided. In the reference form 1, the connection terminal 9 of the plug 10 is elastically connected to the elastic terminal 25. However, in the present reference form, the pressing terminal 325 is connected by contacting the connection terminal 9. The pressing terminal 325 is insulated from the fixture main body 321, and when the plug fixture 320 is fixed to the cylinder head 30, the plug 10 is connected to the distal end side in the axial direction (in the drawing) via the contact terminal 9 that is in contact. Press downward.

Therefore, when the plug 10 is fixed by the plug fixing tool 320 in the same manner as in the reference embodiment 1, the insulator 18 is held by the insulator holding member 24, the pressing terminal 325 is electrically connected to the connection terminal 9, and the plug 10 is pressed downward to effect sealing. A high voltage is supplied to the plug 10 through the pressing terminal 325.
In this way, the diameter of the insertion portion 33 of the plug mounting hole 32 can be reduced by the amount that the cylindrical portion 22 does not exist, so that the space consumed by the plug mounting hole 32 can be reduced, and the intake valve 51 and the exhaust valve 51 can be reduced. The degree of freedom regarding the arrangement of the source valve 52 (see FIG. 7) and other aspects can be increased, and the engine design can be facilitated.

Then, in the manufacturing method of the spark plug 10 used in the above Reference Embodiment 1-3 will be described with the outer electrode 16 a method of forming the protrusions 14t. FIG. 9 is an explanatory view showing a state in which the outer electrode 16 and the protruding portion 14 t are formed on the metal shell 11.
First, a ground electrode body K made of Cu is inserted into and brought into contact with the main metal 11 from below in the figure. Next, one end (the lower end in the figure) of the rod-like outer electrode 16 is brought into contact with the position of the right end in the figure on the tip surface 15a, the switch SW1 is turned on, a large current is passed from the DC power supply Edc, and resistance welding is performed. The outer electrode 16 is fixed to the distal end surface 15a. Further, with the position of the metal shell 11 maintained, the protrusion tip 14t ′ is brought into contact with the left end of the side surface 14b of the front end side main body portion 14 and the switch SW2 is turned on so that the large amount is supplied from the DC power supply Edc. A current is passed, and a protrusion 14t is formed on the side surface 14b by resistance welding.
In this way, the outer electrode 16 and the protrusion 14t are welded so that the position of the protrusion 14t is always in the same positional relationship. Therefore, in the plug 10 of the same product number, the protrusion 14t and the outer electrode are always fixed. The positional relationship with the part 6a can be made the same.
In the above description, the outer electrode 16 is welded first, but the protrusion tip 14t ′ may be welded first.

In the reference forms 1 to 3, as shown in FIG. 10A, a protrusion 14t is formed on a part of the side surface 14b of the distal end side main body portion 14 of the plug 10, and the plug mounting hole 32 corresponds to the distal end side main body. Although the key groove 36 is provided in the portion 34 so that the two are fitted in only one place, such a fitting position limiting shape may be other shapes. In FIG. 10, the description of the internal structure of the cross section of the plug 10 is omitted for simplicity.
For example, what is shown in FIG. 10B is a configuration in which a key groove 14p is provided on the side surface 14b of the distal end side body and a protrusion 36p is provided on the distal end side body corresponding portion 34, contrary to FIG.
10 (c) shows a flat surface 14q obtained by chamfering a part of the tip side main body side surface 14b, and the tip side main body corresponding portion 34 is also provided with a flat surface 36q corresponding thereto. It is.
10 (d) has a substantially egg-shaped cross section provided with a diameter-enlarged portion 14r that is larger than the circular shape indicated by the broken line, instead of the tip side main body side surface 14b. A diameter-expanded portion 36r that matches this is provided.
In any case of such a shape, the position where the distal end side main body portion 14 and the distal end side main body corresponding portion 34 are fitted is limited to one position in the circumferential direction. Therefore, if the positional relationship between the outer electrode fixation portion 16a at these fitting position restriction shape and plug 10 to be constant, in the same manner as in Reference Embodiments 1 to 3, inserted and fitted plug 10 into the plug mounting hole 32 In this case, the position of the outer electrode fixing portion 16a can be determined.

( Reference form 4)
Further, the case where the present invention is applied to a spark plug having a plurality of outer electrodes will be described. The two-pole flat sheet type spark plug 410 shown in FIG. 11 has 2 on the side surface 414b of the front end side body portion 414 of the metal shell 411 as compared with the plug 10 of the reference embodiment 1 provided with one protrusion 14t. The two protrusions 414ta and 414tb are different in that they are fixed to positions 180 degrees apart from each other, that is, opposite to the circumference of the side surface 414b. Also, the outer electrode 416 is different in that the two poles 416A and 416B are formed.
In this case, as indicated by a broken line in FIG. 11 (b), the key groove 436A corresponding to each of the two protrusions 414ta and 414tb described above is formed in the tip-side body corresponding portion 434 in the plug mounting hole of the cylinder head. , B are formed. In this case, when the plug 410 is rotated about the axis O, the plug 410 is fitted into the plug mounting holes at two locations when rotated once. Note that two keyways (436A, B) are required for fitting at two locations, but one protrusion (for example, only 414ta) may be used.

Further, as shown in FIG. 11B, the relationship between the two protruding portions 414ta and 4141tb and the fixing portions 416Aa and Ba of the two outer electrodes 416A and B is the protruding portion 414ta (center is Ta). With reference to the line OTa connecting the central axes O, the fixing portions 416Aa and 416Ba are positioned on the tip surface 415a of 90 degrees and 270 degrees in the circumferential direction angle, respectively.
As described above, in the two-pole plug, due to the relationship between the swirl M2 and the outer electrode fixing portion, as shown in FIG. 28 (b), it is fixed at a position excluding the ranges of θ = ± 30 degrees and 180 ± 30 degrees. The part may be positioned. Thus, using a cylinder head 430 that corresponds to the ignition plug 410 and which has as the reference embodiment (not shown), if so streamline the reference line OTa swirl M2 are matched, the outer electrode fixation portion 416Aa , Ba can be positioned in the above range (specifically, θ = 90 degrees and 270 degrees).
Also in the two-pole plug, not constituting the fitting position restriction shape using projections and the key groove, also may be some other shape, it is the same as Reference Embodiment 1 and the like.
Further, the positions of the key grooves 436A, B and the positional relationship between the protrusions 414ta, tb and the fixing portions 416Aa, Ba need only be positioned outside the range of θ = ± 30 degrees and 180 ± 30 degrees. This is the same as in the first embodiment.

( Reference form 5)
Next, the fitting position restriction shape is formed on the distal end side main body portion of the plug 10 or the like. Specifically, unlike the above-described reference embodiments 1 to 4 in which the protruding portion 14t or the like is formed on the distal end side main body portion 14 or the like, the fitting is limited. The position restriction shape is formed at the tip of the plug.
Figure 12 is a partially cutaway sectional view and a bottom view showing the shape of a spark plug 510 of the single-pole flat sheet type according to the reference embodiment 5. The plug 510 is different from the reference form 1 in that the front end side main body portion 514 of the metal shell 511 is not provided with a protrusion and the protrusion 515t is provided on the side surface 515b of the front end 515.
However, the relationship between the protrusion 515t and the outer electrode fixation portion 16a of the plug 510 of this preferred embodiment is substantially the same as the relationship between the protruding portion 14t and the outer electrode fixation portion 16a of the Reference Embodiment 1, the tip plug 510 When viewed from the side (see FIG. 12B), when the line connecting the center V of the protrusion 515t and the axis O is used as a reference, the circumferential angle of the outer electrode fixing portion 16a (center A) is
VOA = 180 degrees.

  In contrast to this plug 510, as shown in FIG. 13, in the plug mounting hole 532 of the cylinder head 530, the key groove is not formed in the distal end side body corresponding portion 534, but the key end is located on the proximal end side of the distal end corresponding portion 535. A groove 536 is formed. Therefore, when the plug 510 is inserted into the plug mounting hole 532 of the cylinder head 530, as described above, the protrusion 515t is formed at the tip portion 515 of the plug 510, so that the plug 510 is usually not completely fitted. Therefore, the plug 510 is rotated around the axis O. Then, when the protruding portion 515t is fitted into the key groove 536 formed in the tip corresponding portion 535, for example, when the protruding portion 515t is positioned on the right side in the drawing in FIG. 14, the plug 510 falls downward in the drawing. The plug 510 is fitted into the cylinder head 530. That is, in the plug 510, the position (angle) at which the front end side main body portion 515 of the plug 510 and the front end corresponding portion 535 of the plug mounting hole 532 are fitted to each other by the protrusion 515 t and the key groove 536 is 360 ° of the circumference. Limited to one location.

Thereafter, as in the case of the Reference Embodiment 1, using a plug fastener 20 to secure the plug 510. Even such a case, similarly to the above Reference Embodiment 1, when fitted with a plug 510 to the engine can be restricted positional relationship between the swirl M2 and the outer electrode fixation portion 16a. Accordingly, similarly, the engine can be driven to a thin air-fuel mixture, and fuel consumption can be improved.
Note that the protruding portion 515t in the present reference embodiment may be formed by welding the protruding portion tip in a manner similar to the welding of the outer electrode 16, similarly to the above-described welding of the protruding portion 14t (see FIG. 9).
Further, in this preferred embodiment is provided with the projecting portion 515t at the distal end 515, according to the example shown in FIG. 10, the shape of the tip corresponding portion 535 of the tip 515 and the cylinder head 530 of the plug 510, the appropriate What is necessary is just to set it as a fitting position restriction | limiting shape. Moreover, although the example of the plug of 1 pole was shown, it is clear that it may be applied to a plug of 2 poles or more. Further, the protrusions may be provided on both the distal end portion and the distal end side main body portion, and the key groove may be provided on both the distal end corresponding portion and the distal end side main body corresponding portion.

(Embodiment 1 )
In the above reference embodiments 1 to 5, the plug position and the cylinder head are formed with a fitting position restriction shape to restrict the circumferential angle of the plug. However, in this embodiment, the fitting position restriction is applied to the plug and the plug fixture. Indicates what forms the shape. A spark plug 610 shown in FIG. 15 is a partially cutaway sectional view and a bottom view of the spark plug according to the present embodiment. To Reference Embodiment 1, the protrusion 14t is formed in the tip body portion 14, in this embodiment, the base body part 613, more specifically, the protrusion 613t on the side surface of the base body center portion 613b Are different, and the rest is the same.
The positional relationship between the protruding portion 613t and the outer electrode fixing portion 16a is substantially the same as the relationship between the protruding portion 14t and the outer electrode fixing portion 16a of Reference Example 1, and the plug 610 is viewed from the tip side (see FIG. 15 (b)), the angle in the circumferential direction of the outer electrode fixing portion 16a (center A) is set to WOA = 180 degrees with reference to the line connecting the center W of the protrusion 615t and the axis O.

On the other hand, the plug mounting hole 632 formed in the cylinder head 630 is different from the reference embodiment 1-5, as shown in FIG. 16, any of the tip body corresponding portion 634 and the tip corresponding portion 635, a cylindrical shape, the key A groove or the like is not formed.
On the other hand, as shown in FIG. 17, the plug fixture 620 is formed with a key groove 622k that fits the projection 615t on the inner peripheral surface 622c of the tubular portion 622 of the fixture body 621.
Accordingly, when the base end side (the upper side in FIG. 16) of the spark plug 610 is inserted into the tubular portion 622 of the plug fixture 620, the base end side main body central portion 613b of the plug 610 is inserted into the plug 610 as described above. Since the protrusion 613t is formed, the tip surface 622a normally contacts the protrusion 613t and does not fit completely. Therefore, the plug 610 is rotated around the axis O. Then, when the protruding portion 613t is fitted into the key groove 622k formed in the cylindrical portion 622, for example, when the protruding portion 613t is positioned on the right side in the drawing in FIG. 18, the protruding portion 613t becomes the key groove 622k. The plug 510 is fitted to the plug fixture 620, and the distal end surface 622a of the tubular portion comes into contact with the upper surface 614a of the distal end side body 614 of the plug 610. That is, in the plug 610, the position (angle) at which the base end side main body portion 613 and the tubular portion 622 of the plug 610 are fitted to each other by the protrusion 613t and the key groove 622k is limited to one place in 360 degrees of the circumference. Is done.

  In this way, the plug 610 is inserted and fitted into the tubular portion 622 of the plug fixture 620 to form the spark plug assembly 600, and further, as shown in FIG. Plug 610 and cylindrical portion 622 are inserted into 632, and flange portion 623 of plug fixture 620 is fixed to cylinder head 630 with bolts BLa to BLd. Thereby, since the cylindrical part 622 presses the front end side main-body part 614 to the axial direction front end side, it is sealed. Moreover, since the front end side main body part 614 is uniformly pressed in the circumferential direction by the cylindrical part 622, it can be reliably sealed.

As described above, none of the insertion portion 633, the distal end side main body corresponding portion 634, and the distal end corresponding portion 635 of the plug mounting hole 632 is formed with a key groove or the like (see FIG. 16), and the spark plug 610 has a circumferential shape. The plug mounting hole 632 is fitted at any position in the direction.
However, the position of the outer electrode fixing portion 16a in the plug 610 is regulated as follows. That is, as shown in FIG. 16A, the screw holes 637 a to 637 d formed in the cylinder head 630 are arranged asymmetrically with respect to the axis O. That is, the interval x1 between the screw holes 647a and 637b is different from the interval x2 between the screw holes 647c and 637d. More specifically, x1 <x2. Corresponding to the screw holes 637a to 637d, the mounting holes 27a to 27d of the plug fixture 620 are similarly configured such that the distance x1 between the mounting holes 27a and 27b and the distance x2 between the mounting holes 27c and 27d are x1. <X2 (see FIG. 17B).

  Therefore, when the plug fixing device 620 is fixed to the cylinder head 630 using the bolts BLa to BLd, the positions where the mounting holes 27a to 27d of the plug fixing device 620 match the screw holes 637a to 637d are plug fixing. When the tool is rotated in the circumferential direction, it is restricted to one place. That is, in this embodiment, the state in which the bolts BLa to BLd can be screwed is shown in FIG. 19B, in which the key groove 613k formed in the cylindrical portion 622 and the protrusion 613t of the plug 610 are illustrated. Only when located at the middle right end. For this reason, as described with reference to FIG. 15, in the plug 610 of this embodiment in which the positional relationship with the protrusion 613t is set to WOA = 180 degrees, the outer electrode fixing portion 16a In (b), it is located at the left end.

Therefore, similarly to Reference Embodiment 1 (see FIG. 7 (a)), in an engine assembled with the plug 610, because it restricts the positional relationship between the swirl M2 and the outer electrode fixation portion 16a, similarly, until thin mixture Engine Can be driven, and fuel consumption can be improved.
In the present embodiment, the plug mounting hole 632 of the cylinder head 630 need not be processed such as a key groove. On the other hand, since it is easier to form a key groove or the like in the cylindrical portion 622 of the plug fixture 620 than the processing of the cylinder head, the overall cost can be reduced as a whole.

Incidentally, the protrusion 613t of the present embodiment, similarly to the welding protrusion 14t of such reference embodiment 1, may be formed by welding the chip projections by welding with tandem outer electrode 16.
Further, in the present embodiment, the protrusion 613t is provided on the base end side main body portion 613 (base end side main body central portion 613b), and the key groove 622k is provided on the tubular portion 622 of the plug fixture, as shown in FIG. According to the above example, the shapes of the base end side main body portion 613 and the cylindrical portion 622 of the plug 610 may be set to appropriate fitting position limiting shapes. Moreover, although the example of the plug of 1 pole was shown, it is clear that it may be applied to a plug of 2 poles or more.
Furthermore, in the present embodiment, the distal end surface 622a of the tubular portion 622 contacts and presses against the distal end side body portion upper surface 614a of the plug 610. However, the crimped portion of the proximal end body portion 613 at the distal end surface of the tubular portion 622. You may make it press 613a.

  Further, in the present embodiment, the intervals xa and x2 of the mounting holes 27a to 27d of the plug fixture 620 are made different and arranged non-rotationally symmetrically about the axis O. In addition to this, FIG. As shown in FIG. 17, the lengths L1 and L2 of the left and right sides 623a and b of the flange portion 623 are made different (in FIG. 17B, L1 <L2), and the outer shape of the flange portion 623 is non-rotationally symmetric ( The trapezoidal shape in FIG. This is because the orientation of the flange portion 623 can also be determined from its shape. Further, the mounting holes 27a to 27d (and the screw holes 637a to 637d) may be arranged in rotational symmetry (for example, the position of each vertex of the square), and only the outer shape of the flange portion 623 may have a non-rotational symmetry shape. . This is because the orientation of the flange portion 623 can be determined by visual observation or the like.

(Reference form 6)
In the first embodiment, the protrusion 613t is formed on the spark plug, and the key groove 622k is formed on the plug fixing member so as to have a fitting position limiting shape that can be fitted to each other, and the circumferential angle of the plug is restricted. In contrast, in this preferred embodiment, without forming the like protrusion and the keyway in the spark plug and plug fastener, not fitting position restriction shape.
In this reference embodiment, in that this is not the form of projections and keyways, the first embodiment differs only and the others are similar. That is, as shown in FIG. 20, the spark plug 710 according to this reference embodiment, the both portions of the metal shell 711, except that projections and key grooves or the like are not formed. Further, as shown in FIG. 21, the plug fastener 720 according to this preferred embodiment also differs in that the keyway and the like are not formed. Furthermore, the cylinder head plug fixture 720 shown in FIG. 22 is the same as the cylinder head of the first embodiment.

In this reference embodiment, when the spark plug 710 and the plug fixture 720 are combined, first, the circumferential position of the outer electrode 16 (outer electrode fixing portion 16a) of the spark plug 710 is aligned. Further, the plug fixture 720 also aligns each side of the planar shape with respect to the trapezoidal flange 723. In addition, by combining the spark plug 710 and the plug fixture 720, the positional relationship between them is made constant.
Since a high voltage of about 30 kV is applied to the plug 710, it is necessary to prevent current leakage. Therefore, an insulator holding member made of silicon rubber or the like so as to be in close contact with the insulator 18 is attached to the plug fixture 720. 24 is provided. For this reason, after the plug 710 and the plug fixture 720 are assembled, the insulator 18 is firmly held by the insulator holding member 24, so that the spark plug 710 rotates around its axis in normal handling. There is nothing. Accordingly, if the positional relationship between the plug 710 and the plug fixture 720 is matched and then both are combined, the positional relationship between the two is maintained thereafter, so that the circumferential angle of the outer electrode 16 can be made uniform.

Therefore, in this preferred embodiment, as described below, aligning the circumferential positions of the outer electrode 16 of the spark plug 710. That is, an alignment mechanism as shown in FIG. This alignment mechanism is configured as follows. First, a holding mechanism (not shown) holds the plug 710 so that the distal end portion 715 and the outer electrode 16 are on the top, and the plug 710 is rotatable about its axis. The rotating member 740 can be moved toward and away from the distal end 715 of the plug 710 in the axial direction (vertical direction in the figure) of the plug, and can be intermittently rotated around the axis by the motor 741 or the like. ing. A groove 742 having a width and a depth corresponding to the ground electrode 16 of the plug 710 is formed on the bottom surface of the rotating member 740.
As the plug 710 is brought into the alignment mechanism, the rotating member 740 approaches the tip 715 of the plug 710. At this time, the direction of the groove 742 of the rotating member 740 is always set to a predetermined position, that is, a position having a predetermined relationship when assembled to the cylinder head 730 together with the plug fixture 720. Since the position (circumferential position) of the outer electrode 16 is indefinite when it is carried into the alignment mechanism, the groove 742 does not fit the outer electrode 16 in many cases even when the rotating member 740 approaches. The rotating member 740 is on the outer electrode 16 at the bottom surface.

  Next, when the motor 741 is operated and the rotating member 740 is rotated, the rotating member 740 rotates around the axis while sliding on the outer electrode 16 at the bottom surface. Since the outer electrode 16 coincides with the groove 742 during its rotation, the rotating member 740 moves downward by its own weight, and the outer electrode 16 is fitted into the groove 742. Thereafter, the plug 710 rotates together with the rotation of the rotating member 740 together with the outer electrode 16. The rotating member 740 stops rotating when it rotates 360 degrees from the initial position. As a result, the outer electrode 16 is aligned at a fixed position regardless of the initial position.

As for the plug fixture 720, as shown in FIG. 23 (b), the motor 751 rotates the plug fixture 720 placed on the rotating member 750 around the axis O by the same mechanism, and the direction thereof Can be aligned. In addition, since the flange portion 723 of the plug fixture 720 has a trapezoidal shape, the direction of the plug fixture can be aligned by aligning each side of the flange portion 723 by various methods.
In any case, since the plug 710 and the plug fixture 720 can be aligned in a desired direction, the spark plug assembly 700 (see FIG. 24) is constructed by assembling both the plugs while maintaining this state. .
Although the spark plug assembly 700 formed in this way has no projections or the like formed on the plug 710 and the plug fixture 720, the spark plug assembly 700 is formed between the plug fixture 720 and the plug 710, and thus the outer electrode 16. The positional relationship is the same for any spark plug assembly 700.

  Further, as shown in FIG. 25, the plug 710 and the cylindrical portion 722 of the plug fixture 720 are inserted into the plug mounting hole 732 of the cylinder head 730, and the flange portion 723 of the plug fixture 720 is connected to the cylinder with bolts BLa to BLd. Secure to the head 730. Thereby, since the front end surface 722a of the cylindrical part 722 presses uniformly the upper surface 714a of the front end side main-body part 714 of the metal shell 711 in the circumferential direction, it can seal reliably.

As described above, no key groove or the like is formed in any of the insertion portion 733, the distal end side body corresponding portion 734, and the distal end corresponding portion 735 of the plug mounting hole 732 (see FIG. 22). The plug mounting hole 732 is also fitted at the circumferential position. However, as described in the first embodiment, the position where the plug fixing tool 720 can be fixed is restricted to one place by the mounting holes 27a to 27d of the plug fixing tool 720. Therefore, for example, in the state of the spark plug assembly 700, as shown in FIG. 24, if the outer electrode fixing portion 16a is always positioned at the left end in the drawing, the cylinder head 730 is connected to the spark plug. Even after the assembly 700 is assembled, as shown in FIG. 25, the outer electrode fixing portion 16a is located at the left end. Therefore, (see FIG. 7 (a)) in the same manner as in Embodiment 1, in the engine assembled with the plug 710, because it restricts the positional relationship between the swirl M2 and the outer electrode fixation portion 16a, similarly, the engine with a thin mixture Can be driven, and fuel consumption can be further improved.

In this reference embodiment, it is not necessary to provide a keyway or a protrusion in any of the plug mounting hole 732 of the cylinder head 730, the cylindrical portion 722 of the plug fixture 720, and the plug 710. For this reason, it is necessary to use an alignment mechanism when the plug 710 and the plug fixture 720 are combined. However, the protrusions and key grooves are formed on the plug 710 and the plug fixture 720. Therefore, the plug 710 and the plug fixture 720 can be made very inexpensive.
In the above, an example of a plug with one outer electrode is shown, but it is obvious that the present invention may be applied to a plug with two or more poles.
Further, in this reference embodiment, the distal end surface 722a of the tubular portion 722 is in contact with and pressed against the upper surface 714a of the distal end side main body portion 714 of the plug 710, but the distal end surface 722a of the tubular portion 722 is proximal. The caulking part 713a of the main body part 713 may be pressed.

In this reference embodiment, as in the first embodiment, the intervals xa and x2 of the mounting holes 27a to 27d of the plug fixture 720 are made different and arranged non-rotationally symmetrically about the axis O, as shown in FIG. As shown, the lengths L1 and L2 of the left and right sides of the flange portion 723 are made different (L1 <L2) so that the outer shape of the flange portion 723 has a non-rotationally symmetrical trapezoidal shape. Can also be determined from its shape.
Further, the mounting holes 27a to 27d (and the screw holes 737a to 737d of the cylinder head 730) are arranged in rotational symmetry (for example, the position of each vertex of the square), and only the outer diameter shape of the flange portion 723 has a non-rotationally symmetrical shape. It is also good. This is because the orientation of the flange portion 723 can be determined by visual observation or the like.

In the above, the present invention has been described according to the first embodiment with reference to each reference form . However, the present invention is not limited to the first embodiment, and may be appropriately selected without departing from the scope of the present invention. Needless to say, it can be changed and applied.
For example, in the above reference embodiment 1 and embodiment 1 , as a spark plug, a flat seat type plug having a gasket seat surface 14s perpendicular to the axis O and having a gasket 19 is used. It is obvious that the present invention may be applied to a conical sheet type plug in which a tapered surface is formed between the tip portion 15 and the tip portion 15.

Further, in the above reference embodiment 6 , the spark plug assembly 700 is configured by using the motor 741 and the rotating member 740 to align the position of the outer electrode 16 of the plug 710 and combining it with the plug fixture 720 in that state. This method can also be used. For example, the plug 710 is imaged with a camera, the position of the outer electrode 16 is recognized, and the position of the outer electrode 16 is aligned by rotating the plug 710 around its axis so that the outer electrode 16 becomes a predetermined position. You may do it.

It is the fragmentary sectional view and bottom view which show the shape of the 1 pole flat sheet type spark plug concerning the reference form 1. In the ignition plug shown in FIG. 1, it is explanatory drawing which shows the relationship between the projection part and outer electrode which were formed in the metal shell. It is the top view and sectional drawing which show the shape of the plug attachment hole vicinity of the cylinder head concerning the reference form 1. It is the top view and sectional drawing which show the shape of the plug fixing tool concerning the reference form 1. It is explanatory drawing which shows the state which inserted and fitted the ignition plug shown in FIG. 1 in the plug attachment hole of the cylinder head shown in FIG. FIG. 6 is an explanatory view showing a state in which the spark plug inserted into the plug attachment hole shown in FIG. 5 is fixed in the plug attachment hole with the plug fixture shown in FIG. 4. FIG. 4 is an explanatory view showing a state in which the ignition plug shown in FIG. 1 is attached to the engine having the cylinder head shown in FIG. 3, (a) is a partially broken cross-sectional view in the vertical direction, and (b) is the ignition plug. It is the figure seen from the front end side. It is sectional drawing which shows the reference form 2 and 3, (a) shows the thing which pressed the crimping | crimped part among the metal shells of a spark plug with the cylindrical part of reference form 2, and applied to the reference form 2, b) shows that as relates to reference embodiment 3, conducts while pressing the connecting terminals of the spark plug by the pressing pin. It is explanatory drawing which shows a mode that an outer side electrode and a projection part are formed in a metal shell among the manufacturing methods of a spark plug. It is explanatory drawing which shows the example of a fitting position restriction | limiting shape, (a) is what provided the key protrusion in the stick | rod, provided the keyway in the hole, (b) provided the keyway in the stick | rod, and provided the key protrusion in the hole. (C) shows a rod with chamfering and a hole with a shape corresponding to the rod, and (d) shows a rod and hole with a substantially egg shape. It is the fragmentary sectional view and bottom view which show the shape of the spark plug of the 2 pole flat sheet | seat type concerning the reference form 4. It is the fragmentary sectional view and bottom view which show the shape of the 1 pole flat sheet type spark plug concerning the reference form 5. It is the top view and sectional drawing which show the shape of the plug attachment hole vicinity of the cylinder head concerning the reference form 5. FIG. 14 is a plan view and a partially cutaway sectional view showing a state where the ignition plug shown in FIG. 12 is inserted and fitted into the plug mounting hole of the cylinder head shown in FIG. 13. It is the fragmentary sectional view and bottom view which show the shape of the 1 pole flat sheet type spark plug concerning Embodiment 1. FIG. FIG. 4 is a plan view and a cross-sectional view showing the shape of the vicinity of the plug mounting hole of the cylinder head according to the first embodiment. It is sectional drawing and the bottom view which show the shape of the plug fixing tool concerning Embodiment 1. FIG. FIG. 18 is a partially cutaway cross-sectional view showing the spark plug assembly in a state where the spark plug shown in FIG. 15 is inserted and fitted into the tubular portion of the plug fixture shown in FIG. 17. 18 is a plan view and a part showing a state in which the spark plug assembly shown in FIG. 18 is inserted and fitted into the plug mounting hole of the cylinder head shown in FIG. 16, and the spark plug is fixed in the plug mounting hole with a plug fixing tool. FIG. It is the fragmentary sectional view and bottom view which show the shape of the 1 pole flat sheet type spark plug concerning the reference form 6 . It is sectional drawing and the bottom view which show the shape of the plug fixing tool concerning the reference form 6 . It is the top view and sectional drawing which show the shape of the plug attachment hole vicinity of the cylinder head concerning the reference form 6 . It is explanatory drawing which shows a mode that it applies to the reference form 6 and (a) arranges the position of the outer electrode of a spark plug, (b) is explanatory drawing which shows the apparatus which aligns the position of a plug fixture. It relates to a reference embodiment 6, the spark plug shown in FIG. 20 which align the outer electrode is a partially broken sectional view illustrating a plug assembly of the state fixed to the cylindrical portion of the plug fastener shown in Figure 22. 24 is a plan view and a partially broken sectional view showing a state in which the spark plug assembly shown in FIG. 24 is inserted into the plug mounting hole of the cylinder head shown in FIG. 21 and the spark plug is fixed in the plug mounting hole with a plug fixture. is there. It is explanatory drawing which shows the relationship between an engine, a spark plug, and the flow (swirl) of air-fuel | gaseous mixture. (A) is the state seen from the lower side of a cylinder, (b) shows the relationship between a spark plug and a swirl. It is explanatory drawing explaining the relationship between a 1 pole spark plug and a swirl, (a) is explanatory drawing explaining angle (theta) of a swirl and an outer electrode, (b) is a limit when angle (theta) is changed. It is a graph which shows the change of A / F value. It is explanatory drawing explaining the relationship between a bipolar spark plug and a swirl, (a) is explanatory drawing explaining angle (theta) of a swirl and an outer electrode, (b) is a limit when angle (theta) is changed. It is a graph which shows the change of A / F value.

Explanation of symbols

10, 410, 510, 610, 710 Spark plug 11 Metal shell 12 Body portion 13, 413, 513, 613, 713 Base end body portion 13a Caulking portion 14, 414, 514, 614, 714 Tip side body portion 14t, 414ta , 414tb, 515t, 613t Protruding portions 14s, 414s, 514s, 614s, 714s Plug seat surface 15, 415, 515, 615, 715 Tip portion 15a, 415a, 515a, 615a, 715a Tip surface 16 Outer electrode 16a Outer electrode fixing portion 17 Center electrode 18 Insulator 19 Gasket 9 Connection terminal 20, 220, 320, 620, 720 Plug fixture 22, 222, 622, 722 Cylindrical part 23, 323, 623, 723 Flange part 24 Insulator holding member 25 Elastic terminal 325 Press terminal 26 Ignition transformer 27, 6 7 Mounting hole 30, 530, 630, 730 Cylinder head 32, 532, 632, 732 Plug mounting hole 34, 534, 634, 734 Tip side body corresponding portion 34a, 534a Seal surface 35, 535, 635, 735 Tip corresponding portion 36 , 436A, 436B, 536, 622k Keyway 37, 637, 737 Screw hole 50 Engine (internal combustion engine)
51 Intake valve 55 Combustion chamber 600, 700 Spark plug assembly M2 Swirl Lm Stream line

Claims (1)

An internal combustion engine including a cylinder head having a plug mounting hole and a spark plug assembly,
The spark plug assembly is
A central electrode extending in the axial direction;
An insulator surrounding the radial direction of the central electrode and fixing the central electrode;
Surrounding the periphery of the insulator in the radial direction, fixing the insulator, a main body having a base end main body and a front end main body, and a tip having a smaller diameter than the front end main body and extending toward the axial front end A metal shell having a portion;
One or a plurality of outer electrodes fixed to the tip surface of the tip portion;
A spark plug having
It has a substantially cylindrical shape, and when the base end side of the spark plug is inserted therein, it has a cylindrical portion that fits into the base end side main body portion and contacts the main body portion,
A plug fixture for fixing the spark plug in the plug mounting hole by pressing the main body in the axial direction;
With
When the base end side main body portion of the spark plug and the tubular portion of the plug fixture are rotated around the axis while the base end side of the spark plug is inserted into the tubular portion of the plug fixture. In addition, it is a fitting position restriction shape that fits each other only at one place or a plurality of places,
The spark plug of the same product number is the relationship between the circumferential angle of the one or more outer electrode fixing portions around the shaft of the spark plug and the base end side main body portion having the fitting position limiting shape. Is almost the same for all spark plugs,
When the cylindrical part having the fitting position restriction shape is viewed as a plug fixture of the same product number, it is substantially the same for any plug fixture.
The base end side main body portion is fitted to the cylindrical portion of the plug fixture, the main body portion is pressed against the cylindrical portion, and the spark plug is fixed in the plug mounting hole,
Of the intersection of the swirl streamline passing through the center of the ring-shaped tip surface of the tip of the metal shell and the tip surface when viewed from the tip end side in the axial direction of the spark plug, with the upstream intersection as a reference, An internal combustion engine characterized in that one or a plurality of outer electrodes are fixed to a tip surface within a circumferential angle range excluding an angle range of -30 to 30 degrees among the tip surfaces.

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