JP4079989B1 - Multi-point ignition device - Google Patents

Abstract

According to the present invention, it is possible to appropriately set the heat values of all electrode pairs in a multi-point ignition device, and to prevent the electrode pairs from fouling and pre-ignition.
A multipoint ignition device is interposed between a cylinder head and a cylinder block of an engine, and is connected to a head gasket 1 having an opening 3 at a position corresponding to a cylinder opening and a plurality of electrode pairs 2, respectively. A plurality of intermediate members 6 held by the head gasket 1, and the contact areas between the plurality of intermediate members 6 and the head gasket 1 are varied depending on the positions where the plurality of intermediate members 6 are arranged, The heat value of the electrode pair 2 was set individually.
[Selection] Figure 1

Description

  The present invention relates to a multipoint ignition device used in a multipoint ignition engine having a plurality of ignition gaps per combustion chamber.

  Patent Documents 1 and 2 disclose a multipoint ignition engine in which a plurality of electrode pairs constituting an ignition gap are arranged along the cylinder opening of the engine, and an air-fuel mixture in the combustion chamber is ignited from the plurality of ignition gaps. . According to this configuration, the combustion of the air-fuel mixture at the periphery of the combustion chamber is promoted and the engine output and fuel consumption are improved compared to the case where ignition is performed using a conventional spark plug that performs ignition only from the center of the combustion chamber. Is possible.

JP-A-2-123281 JP-A-1-193080

  When the temperature of the electrode pair is lower than the self-cleaning temperature (450 ° C. to 500 ° C.), carbon adheres to the electrode pair, and the secondary voltage leaks and fouling that prevents the spark from flying from the electrode pair occurs. Conversely, when the temperature of the electrode pair rises above 1000 ° C., preignition occurs in which the electrode pair itself becomes a heat source and ignition occurs before the sparks fly. For this reason, also in the above multipoint ignition device, the heat value (heat dissipation) of the electrode pair is set so that the temperature of the electrode pair is within an appropriate range of 450 ° C to 1000 ° C, preferably 500 ° C to 850 ° C with a margin. ) Must be set to an appropriate value.

  The present invention has been made in view of such problems of the prior art, and appropriately sets the heat values of all electrode pairs in a multipoint ignition device to prevent the electrode pairs from fouling and pre-ignition. With the goal.

  In the multipoint ignition device according to the present invention, an interposition member interposed between the cylinder head and the cylinder block of the engine and having an opening at a position corresponding to the cylinder opening, and the plurality of electrode pairs, respectively. A plurality of intermediate members that are connected and held by the interposition member, and a contact area between the plurality of intermediate members and the interposition member varies depending on a position where the plurality of intermediate members are disposed. The heat values of the plurality of electrode pairs are individually set.

  ADVANTAGE OF THE INVENTION According to this invention, the heat value of all the electrode pairs can be set appropriately in a multipoint ignition device, and the generation | occurrence | production of the contamination of an electrode pair and a preignition can be prevented.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following explanation, the heat dissipation of the electrode pair is expressed as `` heat value '' as in the case of the conventional spark plug, the one with good heat dissipation is `` high heat value '', and conversely, the one with poor heat dissipation is `` "The heat value is low."

  FIG. 1 shows a configuration of a multipoint ignition device according to the present invention, and FIG. 2 is a partially enlarged view thereof. In the present embodiment, the multipoint ignition device is integrated with the engine head gasket 1, and when sandwiched between the cylinder head and the cylinder block of the engine, a plurality of electrode pairs 2 are formed along the cylinder opening. Be placed. The electrode pair 2 includes a conducting electrode 2a and a ground electrode 2b, respectively, and forms an ignition gap between the electrodes 2a and 2b.

  A plurality of openings 3 and 4 are formed in the head gasket 1. The largest opening 3 in the center is substantially the same diameter as the cylinder opening, is formed at a position corresponding to the cylinder opening, and constitutes a part of the side wall of the combustion chamber when attached to the engine. An opening 4 arranged around the opening 3 is a water hole connected to a cooling water passage formed in the cylinder head and the cylinder block.

  An intermediate member 6 is connected to each of the plurality of electrode pairs 2, and the plurality of electrode pairs 2 are held by the head gasket 1 by holding the intermediate member 6 in the head gasket 1. Since the electrode pair 2 and the intermediate member 6 are integrally formed of the same material having high heat resistance such as nickel, the boundary between the two members is not clear. However, for convenience of explanation, the radial direction of the opening 3 has a thickness. The portion is referred to as an intermediate member 6, and the portion that extends in a gentle S-shape from both sides and partially protrudes into the opening 3 is referred to as an electrode pair 2.

  The plurality of electrode pairs 2 are electrically connected in series via the intermediate member 6. For this reason, when a high-voltage secondary voltage is applied to the terminal 7, discharge first occurs in the ignition gap of the electrode pair 2 connected to the terminal 7 and the conducting electrode 2 a, and subsequently discharge occurs in the electrode pair 2 adjacent thereto. Discharge occurs in order from the terminal 7 side along the opening 3, and finally, discharge also occurs in the ignition gap of the electrode pair 2 closest to the ground terminal 8.

  Further, as shown in FIG. 3, each intermediate member 6 has an end 6 s on the opening 3 side extending to the periphery of the opening 3, and its end surface is exposed on the inner peripheral surface of the opening 3. In this multipoint ignition device, the contact area between the intermediate member 6 and the head gasket 1 and the surface area of the portion exposed to the opening 3 of the intermediate member 6 (hereinafter referred to as “exposed area”) are positions where the intermediate member 6 is disposed. Thus, the heat value of each electrode pair 2 is set individually. For example, the heat value of the electrode pair 2 arranged at a position where the wall surface temperature of the combustion chamber is high is high, and conversely, the heat value of the electrode pair 2 arranged at a position where the wall surface temperature is low is set low.

  Next, a specific method for adjusting the heat value of the electrode pair 2 will be described. In order to change the heat value of a certain electrode pair 2, at least of the length L and width W of the intermediate member 6 connected to the electrode pair 2 and the height H other than the portion exposed to the opening 3 (see FIG. 3) One is changed, and the contact area between the intermediate member 6 and the head gasket 1 is changed.

  For example, in order to raise (increase) the heat value of one electrode pair 2 to be higher than that of the other electrode pair 2 and to make the electrode pair 2 cool, it is embedded in the head gasket 1 of the intermediate member 6 connected to the electrode pair 2. It is only necessary to increase at least one of the length L, width W, and height H of the portion to be larger than the other electrode pair 2 to increase the contact area between the intermediate member 6 and the head gasket 1. When the contact area between the intermediate member 6 and the head gasket 1 increases, the heat of the electrode pair 2 can easily escape to the cylinder head and cylinder block of the engine via the intermediate member 6 and the head gasket 1. The heat value can be increased.

  In order to further increase the heat value of the electrode pair 2, the end 6 s of the intermediate member 6 connected to the electrode pair 2 may be completely buried in the head gasket 1 as shown in FIG. 4. According to this configuration, the amount of heat received from the combustion gas by the intermediate member 6 decreases, the temperature of the intermediate member 6 decreases, and the heat of the electrode pair 2 easily escapes through the intermediate member 6. The heat value can be further increased.

  Further, from this state, at least one of the length L, the width W, and the height H of the intermediate member 6 connected to the electrode pair 2 is made larger than the other electrode pairs 2 to make contact with the head gasket 1. If the area is increased, the heat value of the electrode pair 2 can be further increased. FIG. 5 shows an example in which the intermediate member 6 is completely buried in the head gasket 1 and the width W of the intermediate member 6 is increased to increase the heat value of the electrode pair 2 connected to the intermediate member 6. .

  Although not shown in the figure, the surface of the intermediate member 6 connected to the electrode pair 2 is subjected to a surface treatment for improving heat dissipation, so that the thermal conductivity from the intermediate member 6 to the head gasket 1 is increased. You may make it raise a heat value further. As the surface treatment applied to the surface of the intermediate member 6, a process of plating the intermediate member 6 with a material (for example, copper, platinum) having higher thermal conductivity than the material of the intermediate member 6 or a minute amount on the surface of the intermediate member 6. The process etc. which form an unevenness | corrugation and increase the contact area of the intermediate member 6 and the head gasket 1 can be used.

  On the other hand, in order to lower (lower) the heat value of the electrode pair 2 than that of the other electrode pair 2 and make the electrode pair 2 burnt, it is embedded in the head gasket 1 of the intermediate member 6 connected to the electrode pair 2. At least one of the length L, width W, and height H of the portion to be formed may be made smaller than the other electrode pair 2 to reduce the contact area with the head gasket 1. When the contact area between the intermediate member 6 and the head gasket 1 decreases, the heat of the electrode pair 2 becomes difficult to escape to the cylinder head and cylinder block of the engine via the intermediate member 6 and the head gasket 1. The heat value can be lowered.

  In order to further reduce the heat value of the electrode pair 2, the length L and the height H of the end face of the end 6s exposed to the opening 3 of the intermediate member 6 connected to the electrode pair 2 are increased, or FIG. As shown in FIG. 3, the end surface of the end 6 s may be curved inward of the head gasket 1 from the state of FIG. 3 to increase the exposed area of the intermediate member 6 to the opening 3. When the exposed area of the intermediate member 6 to the opening 3 increases, the amount of heat transferred from the combustion gas to the electrode pair 2 via the intermediate member 6 increases, and the heat value of the electrode pair 2 can be further reduced.

  Furthermore, as shown in FIG. 7, when the end 6 s is protruded into the opening 3, the exposed area of the intermediate member 6 to the opening 3 is further increased, and the heat value of the electrode pair 2 connected thereto can be further reduced. it can. Further, if the end surface of the end portion 6s protruding into the opening 3 is curved as shown in FIG. 8 to further increase the exposed area of the intermediate member 6 to the opening 3, the electrode pair 2 connected thereto The heat value can be further lowered.

  In the example of FIGS. 6 and 8, the end surface of the end portion 6s is curved to increase the exposed area to the opening 3 of the intermediate member 6. However, in order to increase the exposed area, it is only necessary that unevenness is formed on the end surface. Therefore, instead of curving the end surface of the end portion 6s, grooves, depressions, protrusions, or the like may be formed on the end surface of the end portion 6s. In the configuration of FIG. 8, the curved surface is not limited to the end surface of the end portion 6s, but may be the upper surface or the lower surface of the exposed end portion 6s. Further, in the configuration of FIGS. 7 and 8, the length L and the height H of the end portion 6 s projected into the opening 3 and the projection amount X into the opening 3 are changed, whereby the opening 3 of the intermediate member 6 is changed. It is also possible to change the exposed area.

  Here, in changing the contact area between the intermediate member 6 and the head gasket 1, the contact area is changed mainly by changing the dimensions of the intermediate member 6. However, the method for changing the contact area is the same. Not exclusively. As a method of changing the contact area, for example, unevenness is formed on the surface of the intermediate member 6 or the contact surface of the head gasket 1 with the intermediate member 6 so that the contact area between the intermediate member 6 and the head gasket 1 is increased. Good. On the contrary, the contact area may be reduced by forming a gap between the intermediate member 6 and the head gasket 1 using the unevenness or disposing a heat insulating material in the gap.

  Thus, according to the present invention, it is possible to individually set the heat values of the electrode pairs 2, and by appropriately setting the heat values of all the electrode pairs 2, The occurrence of ignition can be prevented.

  It should be noted that the specific methods for adjusting the heat value described above can be executed in combination as appropriate, thereby realizing a wide range of heat value adjustment.

It is a block diagram of the multipoint ignition device which concerns on this invention. It is the elements on larger scale of the multipoint ignition device which concerns on this invention. It is a figure for demonstrating the heat value adjustment method. It is a figure for demonstrating the heat value adjustment method. It is a figure for demonstrating the heat value adjustment method. It is a figure for demonstrating the heat value adjustment method. It is a figure for demonstrating the heat value adjustment method. It is a figure for demonstrating the heat value adjustment method.

Explanation of symbols

1 Head gasket (intervening member)
2 Electrode pair 3 Opening 6 Intermediate member 6s End

Claims (10)

In the multipoint ignition device in which a plurality of electrode pairs constituting the ignition gap are arranged along the cylinder opening of the engine,
An interposed member interposed between a cylinder head and a cylinder block of the engine and having an opening at a position corresponding to the cylinder opening;
A plurality of intermediate members connected to the plurality of electrode pairs, respectively, and held by the intervention member;
With
The heat values of the plurality of electrode pairs are individually set by varying the contact area between the plurality of intermediate members and the interposition member depending on the position where the plurality of intermediate members are arranged. Point ignition device.   By making at least one of the length, width, and height of the plurality of intermediate members different, the contact area between the plurality of intermediate members and the interposition member depends on the position where the plurality of intermediate members are arranged. The multipoint ignition device according to claim 1, wherein the multipoint ignition device is different.   3. The heat value of the electrode pair connected to the intermediate member exposed to the opening is lowered by exposing at least one of the plurality of intermediate members to the opening. 4. Multi-point ignition device.   The heat value of the electrode pair connected to the at least one intermediate member is further reduced by increasing a surface area of a portion exposed to the opening of the at least one intermediate member. Multi-point ignition device.   The surface area of the part exposed to the opening of the at least one intermediate member is increased by providing irregularities on the surface of the part exposed to the opening of the at least one intermediate member. Multi-point ignition device.   5. The surface area of the portion exposed to the opening of the at least one intermediate member is increased by projecting the portion exposed to the opening of the at least one intermediate member into the opening. 5. The multipoint ignition device according to 5.   The heat value of the electrode pair connected to the intermediate member subjected to the surface treatment is increased by performing a surface treatment for improving heat dissipation on at least one of the plurality of intermediate members. The multipoint ignition device according to any one of 6. The surface treatment is, multipoint ignition device according to claim 7, wherein the is to plating of high thermal conductivity material than prior Symbol throughout member on the surface of the at least one intermediate member.   The multipoint ignition device according to claim 7 or 8, wherein the surface treatment is a treatment of forming irregularities on a surface of the at least one intermediate member.   The multipoint ignition device according to any one of claims 1 to 9, wherein the plurality of electrode pairs and the intermediate member are integrally formed of the same material.

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