internal combustion engine

Abstract

To smoothly introduce a new air-fuel mixture from outside to an auxiliary chamber to improve ignitability in an internal combustion engine having a cap in which the auxiliary chamber accommodating at least a center electrode of an ignition plug is provided.SOLUTION: In an internal combustion engine 1 that includes an ignition plug 2 mounted to a cylinder head 4 and having a center electrode 21 and a cap 3 in which an auxiliary chamber 3s accommodating the center electrode 21 of the ignition plug 2 and communicated with outside via a plurality of nozzle holes 3s1, 3s2 is provided, the nozzle holes 3s1, 3s2 are provided in upper and lower parts of the auxiliary chamber 3s, respectively. A guide part 3g is provided between the nozzle hole 3s1 provided in the upper part of the auxiliary chamber 3s and the nozzle hole 3s2 provided in the lower part of the auxiliary chamber.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a spark ignition internal combustion engine. [Background technology]

[0002] Conventionally, in spark ignition internal combustion engines, it has been considered to use a cap that has an internal sub-chamber that houses the center electrode and ground electrode of the spark plug in order to optimize the propagation speed of combustion (see, for example, Patent Document 1).

[0003] In the configuration described in Patent Document 1, after the air-fuel mixture is ignited in the auxiliary chamber, the combustion is propagated from the auxiliary chamber to another part of the combustion chamber (main chamber) through a through hole provided in the cap. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-159778 Summary of the Invention [Problem to be solved by the invention]

[0005] Most conventional internal combustion engines x1 of this type are port-injected, spark-ignition, four-stroke engines that inject fuel such as gasoline or hydrogen into an intake port (not shown) and introduce an air-fuel mixture into the combustion chamber. As shown in Fig. 3, the engine includes at least a cylinder head x4, an ignition plug x2, and a cap x3 located between the spark plug x2 and the cylinder head x4. The cap x3 houses the center electrode x21 and the ground electrode x22 of the spark plug x2 and has an auxiliary chamber x3s inside that communicates with the outside via a plurality of nozzle holes x3s1. Note that the spark plug x2 is not cut away in Fig. 3.

[0006] In this internal combustion engine x1, the air-fuel mixture is introduced from the main chamber x51 of the combustion chamber x5 to the auxiliary chamber x3s during the compression stroke, but the injection hole x3s1, which connects the inside and outside of the auxiliary chamber x3s, has two functions: to exhaust burned gas from the auxiliary chamber to the outside and to introduce new air-fuel mixture from the outside into the auxiliary chamber. Therefore, there is a problem that the introduction of new air-fuel mixture from the outside into the auxiliary chamber is hindered by residual burned gas, mainly in the upper part of the auxiliary chamber x3s, and ignition performance deteriorates.

[0007] The present invention has been made with the above points in mind, and aims to improve ignition performance in an internal combustion engine having a cap with an auxiliary chamber inside that houses at least the center electrode of an ignition plug, by smoothly introducing new air-fuel mixture from the outside into the auxiliary chamber. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the invention according to claim 1 provides an internal combustion engine including a spark plug attached to a cylinder head and having a center electrode, and a cap which houses the center electrode of the spark plug and has an auxiliary chamber therein which communicates with the outside via a plurality of nozzle holes, wherein the nozzle holes are provided at the upper and lower parts of the auxiliary chamber, and a nozzle hole is provided between the nozzle hole provided at the upper part of the auxiliary chamber and the nozzle hole provided at the lower part of the auxiliary chamber. a plate-like nozzle protruding from a portion of the cap adjacent to the lower side of the nozzle hole provided at the upper portion toward the sub-chamber and inclining upward; With a guide section The guide portion is formed so as not to straddle a line connecting the tip of the center electrode of the ignition plug and the nozzle hole provided in the upper part, and so as not to straddle a line connecting the tip of the center electrode of the ignition plug and the nozzle hole provided in the lower part. It constituted an internal combustion engine.

[0009] In the invention according to claim 2, in addition to the above-mentioned configuration, There are a plurality of nozzle holes in the upper part of the auxiliary chamber, and there are a plurality of nozzle holes in the lower part of the auxiliary chamber. is doing. [Effects of the Invention]

[0010] According to the present invention, in an internal combustion engine having a cap with an auxiliary chamber therein that houses the center electrode and ground electrode of an ignition plug, the air-fuel mixture can be introduced from a nozzle hole below the guide portion and the burned gas can be discharged from a nozzle hole above the guide portion, thereby smoothly introducing new air-fuel mixture from outside into the auxiliary chamber and improving ignition performance. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram showing a main part of an internal combustion engine according to an embodiment of the present invention; [Figure 2] FIG. 4 is a diagram showing a main part of an internal combustion engine according to another embodiment of the present invention. [Figure 3] FIG. 1 is a diagram showing a main part of a conventional internal combustion engine. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of the present invention will now be described with reference to FIG.

[0013] The internal combustion engine 1 according to this embodiment is a port-injection, spark-ignition, four-stroke engine that injects fuel such as gasoline or hydrogen into an intake port (not shown) and introduces an air-fuel mixture into the combustion chamber, and as shown in Fig. 1, it is equipped with at least an ignition plug 2 and a cap 3 that is interposed between the spark plug 2 and a cylinder head 4, houses a center electrode 21 and a ground electrode 22 of the spark plug 2, and has an auxiliary chamber 3s therein that communicates with the outside via a plurality of injection holes 3s1, 3s2. Note that the spark plug 2 is shown in Fig. 1 without being cut away.

[0014] The spark plug 2 is a conventional one that is attached to the cylinder head 6 and includes a center electrode 21 and a ground electrode 22. Although the entire spark plug 2 is shown as a single unit in FIG. 1, insulation is provided between the center electrode 21 and the ground electrode 22.

[0015] As described above, the cap 3 is interposed between the spark plug 2 and the cylinder head 4. In this embodiment, the cap 3 is attached to the spark plug 2, and then the cap 3 and the spark plug 2 are assembled to the cylinder head 4.

[0016] The cap 3 also has an auxiliary chamber 3s therein that houses the center electrode 21 and the ground electrode 22 of the spark plug 2. The auxiliary chamber 3s is hemispherical and communicates with the outside, i.e., the main chamber 51 of the combustion chamber 5, via injection holes 3s1 and 3s2. In other words, as shown in Fig. 1, the cap 3 has the auxiliary chamber 3s formed at its bottom that houses the center electrode 21 and the ground electrode 22 and communicates with the main chamber 51 of the combustion chamber 5.

[0017] In this embodiment, an upper injection hole 3s1 is provided in the upper part of the auxiliary chamber 3s, a lower injection hole 3s2 is provided in the lower part of the auxiliary chamber 3s, and a guide portion 3g is provided between the upper injection hole 3s1 and the lower injection hole 3s2.

[0018] More specifically, a plurality of lower injection holes 3s2 are provided near the bottom of the cap 3, and a plurality of upper injection holes 3s1 are provided above the lower injection holes 3s2, more specifically in the upper half of the auxiliary chamber 3s. A plate-shaped guide portion 3g is provided that protrudes from a portion adjacent to and below the upper injection holes 3s1 and slopes upward toward the auxiliary chamber 3s. This guide portion 3g is formed so as not to cross the lines connecting the tip of the center electrode 21 and each of the injection holes 3s1 and 3s2, or the lines connecting the tip of the ground electrode 22 and each of the injection holes 3s1 and 3s2.

[0019] In this embodiment, during the compression stroke, an air-fuel mixture is introduced into the auxiliary chamber 3s from the lower injection hole 3s2. The introduced air-fuel mixture flows along the guide portion 3g and is then pushed to the upper part of the auxiliary chamber 3s. The burned gas remaining in the upper part of the auxiliary chamber 3s is pushed out by the introduced air-fuel mixture, flows along the guide portion 3g, and is then discharged from the auxiliary chamber 3s (main chamber 51) through the upper injection hole 3s1. That is, during the compression stroke, the air-fuel mixture flows from the lower injection hole 3s2 below the guide portion 3g and along the guide portion 3g before reaching the upper part of the auxiliary chamber 3s, and then flows from the upper part of the auxiliary chamber 3s above the guide portion 3g and along the guide portion 3g before flowing toward the upper injection hole 3s1.

[0020] As described above, when the air-fuel mixture is introduced into the sub-chamber 3s, a spark ignition occurs, and the ignited air-fuel mixture in the sub-chamber 3s is introduced into the main chamber 51 through the nozzle holes 3s1 and 3s2, whereby combustion propagates.

[0021] As described above, according to this embodiment, the upper injection hole 3s1 is located at a position that should be the upper part of the auxiliary chamber 3s, the lower injection hole 3s2 is located near the bottom of the cap 3, and the guide portion 3g is provided at a height position between the upper injection hole 3s1 and the lower injection hole 3s2. Therefore, as described above, in the auxiliary chamber 3s, the air-fuel mixture flows from the lower injection hole 3s2 below and along the guide portion 3g before reaching the upper part of the auxiliary chamber 3s, and flows from the upper part of the auxiliary chamber 3s above the guide portion 3g along the guide portion 3g before heading toward the upper injection hole 3s1. Therefore, new air-fuel mixture can be smoothly introduced from the outside to the inside of the auxiliary chamber 3s, improving ignition performance.

[0022] The present invention is not limited to the above-described embodiment.

[0023] For example, as shown in FIG. 2, a configuration in which the guide portion is configured using a ground electrode is conceivable.

[0024] The internal combustion engine A1 shown in Fig. 2 is a port-injection, spark-ignition, four-stroke engine that injects fuel such as gasoline or hydrogen into an intake port (not shown) and introduces an air-fuel mixture into the combustion chamber, and as shown in the figure, is equipped with at least an ignition plug A2 and a cap A3 that is interposed between the spark plug A2 and a cylinder head A4, houses the center electrode 21 of the spark plug A2, and has an auxiliary chamber A3s inside that communicates with the outside, i.e., the main chamber A51 of the combustion chamber A5, via multiple injection holes A3s1 and A3s2. Note that the spark plug A2 is shown without being cut away in Fig. 2.

[0025] The spark plug A2 of this embodiment has a center electrode A21 but does not have a ground electrode. Instead, a ground electrode A31 is provided inside the cap A3.

[0026] Furthermore, in this embodiment, the ground electrode A31 functions as a guide portion. In other words, the cap A3 in this embodiment has a plurality of lower injection holes A3s2 near its bottom, and a plurality of upper injection holes A3s1 above the lower injection holes A3s2, more specifically, in a portion that will become the upper half of the auxiliary chamber A3s. The ground electrode A31 is provided so as to protrude into the auxiliary chamber A3s from a portion adjacent and below one of the upper injection holes A3s1, and a guide portion A3g is provided so as to protrude into the auxiliary chamber A3s from a portion adjacent and below another of the upper injection holes A3s1.

[0027] In this embodiment, too, the air-fuel mixture is introduced into the auxiliary chamber A3s through the lower injection hole A3s2 during the compression stroke. The introduced air-fuel mixture flows along the ground electrode A31 or the guide portion A3g and is then pushed to the upper part of the auxiliary chamber A3s. The burned gas remaining in the upper part of the auxiliary chamber A3s is pushed out by the introduced air-fuel mixture, flows along the ground electrode A31 or the guide portion A3g, and is then discharged from the auxiliary chamber A3s (main chamber A51) through the upper injection hole A3s1.

[0028] With this arrangement, the ground electrode on the spark plug A2 side can be omitted, leading to cost reduction.

[0029] Furthermore, the shape of the auxiliary chamber is not limited to a hemispherical shape and may be set arbitrarily.

[0030] Furthermore, the guide portion may be formed in a ring shape along the inner wall of the sub-chamber.

[0031] Additionally, the cap may be provided integrally with the cylinder head or the spark plug.

[0032] The positions and number of the injection holes may also be set arbitrarily. However, as in the above-described embodiment, if the guide portion (or the ground electrode functioning as the guide portion) is provided at a position adjacent to and below the upper injection hole, the guide portion can be used to effectively guide the burned residual gas to the upper injection hole, thereby effectively scavenging the residual gas.

[0033] In addition, various modifications may be made without departing from the spirit of the present invention. [Explanation of symbols]

[0034] 1, A1...internal combustion engine 2, A2...Spark plug 21, A21...center electrode 3. A3...Cap 3s, A3s…Antechamber 3s1, A3s1...(Holes at the top of the auxiliary chamber) 3s2, A3s2...(Holes at the bottom of the auxiliary chamber) 3g, A3g...Guide section A31…Ground electrode

Claims

1. a spark plug attached to the cylinder head and having a center electrode; a cap that houses a center electrode of the ignition plug and has an auxiliary chamber therein that communicates with the outside through a plurality of injection holes, the nozzle holes are provided at the upper and lower parts of the sub-chamber, a plate-like guide portion that projects from a portion of the cap adjacent to and below the upper nozzle hole toward the interior of the auxiliary chamber and that is inclined upward is provided between the upper nozzle hole and the lower nozzle hole of the auxiliary chamber, The guide portion is formed so as not to straddle a line connecting the tip of the center electrode of the ignition plug and the nozzle hole provided in the upper part, and so as not to straddle a line connecting the tip of the center electrode of the ignition plug and the nozzle hole provided in the lower part.

2. An internal combustion engine as described in claim 1, wherein there are multiple nozzle holes in the upper part of the auxiliary chamber and multiple nozzle holes in the lower part of the auxiliary chamber.

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