JPH03107519A - Combustion chamber structure for multiple valve engine - Google Patents

Abstract

PURPOSE:To create appropriate swirls so as to improve combustibility by forming intake guide walls, protruding respectively toward the inside of a combustion chamber, at two places among plural intake exhaust port opening parts in the wall surface part of the combustion chamber. CONSTITUTION:In the wall surface part of a combustion chamber, a wall surface forming part 10A is disposed between one intake port opening part 9 among three intake port opening parts 7-9 disposed along the peripheral direction of a cylinder and one exhaust port opening part 12 adjacent to the intake port opening part 9. The wall surface forming part 10A is bent along the specified part so as to form an intake guide wall surface 50A protruding toward the inside of the combustion chamber 5. A wall surface forming part 10B is also disposed between the intake port opening part 9 and the adjoining intake port opening part 8, as well as provided with an intake guide wall surface 50B formed in the same avbove-mentioned way. Appropriate swirls are thereby created with relatively simple structure, thus improving the combustibility of mixture.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides a plurality of independent intake ports that deliver intake air to a combustion chamber through a plurality of intake port openings, each of which is opened and closed by an intake valve. In a multi-valve engine,
The present invention relates to a combustion chamber structure that forms a combustion chamber in which a plurality of intake port openings are formed.

(Prior art) In the field of engines installed in vehicles, in order to improve the intake efficiency in the combustion chamber and improve the output characteristics without expanding the volume of the combustion chamber, the intake air is A multi-valve engine is known in which a plurality of port sections and a plurality of exhaust port sections are provided. In such a multi-valve engine, a plurality of intake port openings formed by opening each of the plurality of intake port portions into the combustion chamber are opened and closed by the plurality of intake valves, and the combustion chamber is opened and closed by the plurality of intake valves. Intake air is supplied through a plurality of intake port openings to the combustion chamber, and at that time, in order to generate a swirl to improve the combustibility of the air-fuel mixture in each combustion chamber, the method disclosed in Japanese Patent Laid-Open No. 61-215422, for example, As shown in FIG. A masking is provided on the peripheral edge to form an intake guide wall surface that protrudes into the combustion chamber along the outer side of the peripheral edge, and a masking is provided on the peripheral edge to form an intake guide wall surface that protrudes into the combustion chamber. It has been proposed to provide a control valve that is closed at low speeds and low loads to regulate the flow direction of intake air supplied into the combustion chamber.

(Problem to be Solved by the Invention) However, as described above, three intake port openings arranged along the circumferential direction of the cylinder are formed in each combustion chamber in a multi-valve engine, and three intake port openings are arranged along the circumferential direction of the cylinder. Masking is provided along the outer part of the peripheral edge of the centrally located opening to form an intake guide wall surface that protrudes into the combustion chamber. When a control valve is installed in the combustion chamber, a stable swirl flowing along the circumferential direction of the cylinder is formed in the combustion chamber, but turbulence of the air-fuel mixture near the spark plug, which is located in the center of the combustion chamber, is generated. This has the disadvantage that the combustibility of the air-fuel mixture in the combustion chamber cannot be sufficiently improved. Cooling loss becomes significant, leading to a decrease in thermal efficiency, and there is a possibility that intake resistance during high loads may increase.

In view of this, the present invention is provided in a multi-valve engine equipped with a plurality of independent intake port sections that send intake air into a combustion chamber through a plurality of intake port opening sections, each of which is opened and closed by an intake valve. It has a relatively simple configuration, and
An object of the present invention is to provide a combustion chamber structure for a multi-valve engine, which can form a combustion chamber in which an appropriate swirl is formed and the combustibility of an air-fuel mixture can be sufficiently improved.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the combustion chamber structure of a multi-valve engine according to the present invention includes a combustion chamber wall portion that forms a combustion chamber space at one end of a cylinder in the engine. The first intake valves are arranged in sequence along the circumferential direction of the cylinder and are opened and closed by a plurality of intake valves. A second and third intake port opening, and an exhaust port opening formed at a position facing them and opened and closed by an exhaust valve are disposed, and the exhaust port opening in the wall surface of the combustion chamber and A first intake guide wall surface is provided at a position between the adjacent first intake port opening and protrudes into the combustion chamber space along the peripheral edge of the first intake port opening, and At a position between the first intake port opening and the adjacent second intake port opening on the combustion chamber wall, along the peripheral edge of the second intake port opening, inside the combustion chamber space. A second protruding intake guide wall surface is provided to define a combustion chamber.

(Function) In the combustion chamber structure of the multi-valve engine according to the present invention configured as described above, the intake air introduced into the combustion chamber through the first intake port opening is provided in the wall surface of the combustion chamber. At the same time, the intake air introduced into the combustion chamber through the second intake port opening flows along the second intake guide wall provided on the combustion chamber wall. The air flows along the central part of the combustion chamber with a higher velocity than the intake air through the first intake port opening.As a result, the first 1. A stable swirl is generated within the combustion chamber by the intake air supplied to the combustion chamber through each of the second and third intake port openings, and the generated swirl faces the center of the combustion chamber. The turbulent flow of intake air is generated in the vicinity of the ignition plug, and therefore, the combustibility of the air-fuel mixture in the combustion chamber is effectively improved.

The generation of swirl in the combustion chamber that improves the combustibility of the air-fuel mixture in the combustion chamber is caused by the fact that the first intake guide wall surface is connected to the exhaust port opening and the first
The second intake guide wall surface is provided so as to protrude inside the combustion chamber space along the peripheral edge of the first intake port opening at a position between the first intake port opening and the first intake port opening. , which protrudes into the combustion chamber space along the peripheral edge of the second intake port opening at a position between the first intake port opening and the second intake port opening adjacent thereto; For example, the first . This means that there is no increase in intake resistance at the three intake port portions forming the second and third intake port openings, respectively.

(Example) FIG. 2 shows a combustion chamber portion and surrounding portions of an engine to which an example of the combustion chamber structure of a multi-valve engine according to the present invention is applied.

In FIG. 2, a cylinder head 4 is disposed via a gasket on a cylinder block 3 in which a cylinder 2 in which a piston 1 is disposed is formed, and a combustion chamber 5 is formed between the cylinder head 4 and the upper part of the cylinder 2. A combustion chamber wall portion is provided as a recessed portion, and a spark plug 6 whose tip portion faces the center portion of the combustion chamber 5 projects from the combustion chamber wall portion. In addition, three intake port openings 7 are arranged in the wall surface of the combustion chamber along the circumferential direction of the cylinder 2.
, 8 and 9 are provided, and the intake port opening 8 is located between the intake port openings 7 and 9. (not visible in FIG. 2). Furthermore, a pair of exhaust port openings 11 and 12 are provided in the wall surface of the combustion chamber at positions opposite to the three intake port openings 7.8 and 9 (second
In the figure, exhaust port opening 12 is behind exhaust port opening 11).

The cylinder head 4 has a branched intake port section 13, which is configured to form an intake port opening 7 at its intake downstream end. a branched intake port section 14 that forms the intake port opening 8 at its intake downstream end;
A branch intake port section 15 is formed in which the intake port opening 9 is formed at its intake downstream end (the branch intake port section 13 has a branch intake port section 15 with respect to the branch intake port section 14). ), and the exhaust port opening 11
A branch exhaust port portion 1 is formed at the exhaust upstream end.
6 and an exhaust port opening 12 are formed at the upstream end of the exhaust gas. 3
The intake upstream portions of the branch intake port I portions 13, 14 and 15 form a confluence portion, and a common intake port in which the fuel injection valve 18 is disposed toward the branch intake port 1 portion 14. It is connected to the passage section 19, and is also connected to the branch exhaust port section 1.
The exhaust downstream portions of exhaust gases 6 and I7 merge and are connected to a common exhaust passage section 20.

Further, the cylinder head 4 is provided with an intake side valve mechanism 22 and an exhaust side valve mechanism 23.

The intake side valve mechanism 22 has a camshaft 24 . An intake valve 28 that is driven by a camshaft 24 via a rocker arm 25 to open and close the intake port opening 7. An intake valve 29 that is driven by the camshaft 24 via the rocker arm 26 to open and close the intake port opening 8; and an intake valve that is driven by the camshaft 24 via the rocker arm 27 to open and close the intake port opening 9. 30. Hydrolink lash adjusters 33, 34 and 35 act on the rocker arms 25, 26 and 27, respectively, and intake port openings 7 and 8 act on the intake valves 28, 29 and 30, respectively. and 9 in the direction of closing (the rocker arm 25, intake valve 28 and hydraulic lash adjuster 33 are not shown in FIG. 2). On the other hand, the exhaust side valve mechanism 23 has a camshaft 36. An exhaust valve 40 is driven by the camshaft 36 through the rocker arm 37 to open and close the exhaust port opening 12, and an exhaust valve 40 is driven by the camshaft 36 through the rocker arm 37 to open and close the exhaust port opening 11. It is configured to include an exhaust valve 39. Hydraulic lash adjusters 41 and 42 act on the rocker arms 37 and 38, respectively, and the exhaust valves 39 and 40 are actuated in a direction that closes the exhaust port openings 11 and 12, respectively. (In FIG. 2, the rocker arm 38, exhaust valve 40, and hydraulic lash adjuster 42 are actuated by a spring that biases the rocker arm 37, exhaust valve 39, and hydraulic lash adjuster 42, respectively. (behind adjuster 41).

FIG. 1 shows a cylinder 2 in an example of the inside of a combustion chamber 5 of a multi-valve engine according to the present invention, which is applied to an engine having a combustion chamber portion configured as described above and its surrounding area.
The intake valve 2 is provided on the wall of the combustion chamber located at the top of the
8. Intake port opening 7 opened and closed by 29 and 30
, 8 and 9, 1 and the respective arrangement positions of the exhaust port openings 11 and 12 that are opened and closed by the exhaust valves 39 and 40, and the wall surface provided on the combustion chamber wall surface so as to protrude into the combustion chamber 5 The positions and shapes of the forming part 10A and IOB, the positions and directions of the branch intake bow 1 parts 13, 14 and 15, and the branch exhaust port parts 16 and 17, as seen from the cylinder 2 side. show.

As shown in FIG. 1, on the wall surface of the combustion chamber,
Intake port opening 9 of three intake port openings 7.8 and 9 arranged along the circumferential direction of the cylinder 2
and the exhaust port opening 12, which is adjacent to the intake port opening 9, of the pair of exhaust port openings II and 12 arranged opposite to the intake port openings 7°8 and 9. A wall forming portion 10A is provided at a position between the intake port opening 9 and the wall forming portion 10A.
An intake guide wall surface 50A that is curved along the peripheral edge of the exhaust port opening 12 and projects inside the combustion chamber 5.
It is said to form a

2 In addition, a wall surface forming portion 10B is provided at a position between the intake port opening 9 of the three intake port openings 7.8 and 9 and the intake port opening 8 adjacent thereto on the wall surface portion of the combustion chamber. is provided, and this wall surface forming portion 10B is
The intake guide wall surface 50B is curved along a portion of the peripheral edge of the intake port opening 8 that is close to the peripheral edge of the combustion chamber wall surface, and projects inside the combustion chamber 5.

The height of the protrusion of the intake guide wall surface 50A toward the inside of the combustion chamber 5 is greater than the height of the protrusion of the intake guide wall surface 50B toward the inside of the combustion chamber 5.

Under such a configuration, the arrow AA shown in FIG.
As shown, the intake air introduced into the combustion chamber 5 through the intake port opening 8 from the branch intake port section 14 located at the center of the branch intake port sections 13, 14 and 15, is introduced into the combustion chamber 5 through the intake port opening 8. The flow is assumed to flow along the intake guide wall surface 50B with a relatively high velocity, and as shown by the arrow AB shown in FIG. The intake air introduced through the opening part 9 passes through the intake guide wall surface 50Δ in the combustion chamber 5 at a relatively low flow velocity.
Further, as shown by the arrow AC shown in FIG. The intake air introduced through 7 enters the combustion chamber 5
Within the combustion chamber, the fluid flows along the peripheral edge of the wall surface of the combustion chamber at a relatively low flow velocity. The intake air introduced into the combustion chamber 5 through the intake port opening 8 has a flow velocity higher than that of the intake air introduced into the combustion chamber 5 through the intake port opening 9 from the center of the combustion chamber 5 to the wall surface of the combustion chamber. It is assumed that the liquid flows toward the periphery. By introducing the intake air into the combustion chamber 5 through the intake port openings 7, 8, and 9 in this manner, a stable swirl is generated within the combustion chamber 5 without a complicated configuration, and a stable swirl is generated within the combustion chamber 5. The swirl causes a turbulent flow in the vicinity of the spark plug 6, which faces the center of the combustion chamber 5, and as a result, the combustibility of the mixture in the combustion chamber 5 is improved.

Further, since the protrusion height of the intake guide wall surface 50A toward the inside of the combustion chamber 5 is larger than the height of the protrusion toward the inside of the combustion chamber 5 of the intake guide wall surface 50B, an intake port opening is formed in the combustion chamber 5. A part of the intake air introduced through the combustion chamber 9 is guided in the flow direction of the intake air introduced into the combustion chamber 5 through the intake port opening 8, and the swirl generated within the combustion chamber 5 is made even stronger. .

Note that the exhaust gas generated in the combustion chamber 5 flows from the exhaust port openings 11 and 12 to the branch exhaust port portions 16 and 1, respectively.
7 to the common exhaust passage section 20.

(Effects of the Invention) As is clear from the above description, according to the combustion chamber structure of the multi-valve engine according to the present invention, there are a plurality of intake port openings that feed intake air into the combustion chamber through a plurality of intake port openings, each of which is opened and closed by an intake valve. In a multi-valve engine equipped with 5 independent intake port sections, the intake air introduced into the combustion chamber through the first intake port opening is connected to the first intake port opening in the combustion chamber wall section and the exhaust gas adjacent thereto. The flow is caused to flow along a first intake guide wall surface provided along the peripheral edge of the first intake port opening at a position between the first intake port opening and the second intake guide wall in the combustion chamber. Intake Bow 1 - A second intake port opening at a location where the intake air introduced through the opening is between the second intake port opening and the adjacent first intake port opening in the wall of the combustion chamber. The air flows along the second intake guide wall surface provided along the peripheral edge of the combustion chamber, and flows toward the center of the combustion chamber at a higher flow velocity than the intake air through the first intake port opening. It is said that As a result, with a relatively simple configuration, the first. A stable swirl is generated within the combustion chamber by the intake air supplied to the combustion chamber through each of the second and third intake port openings, and the generated swirl faces the center of the combustion chamber. A turbulent flow of intake air is generated in the vicinity of the plug, and therefore, the combustibility of the air-fuel mixture in the combustion chamber is effectively improved.

The generation of swirl in the combustion chamber that improves the combustibility of the air-fuel mixture in the combustion chamber is, for example, the first
．． Regardless of the shapes of the three intake port portions forming the second and third intake port openings, the first and second intake guide walls are provided on the combustion chamber wall. Therefore, there is an advantage that there is no increase in intake resistance at each intake port portion, etc.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the shape and arrangement relationship of each part in an example of the combustion chamber structure of a multi-valve engine according to the present invention, and FIG. 2 is a schematic diagram showing an example of the combustion chamber structure of a multi-valve engine according to the present invention. FIG. 2 is a cross-sectional view showing a combustion chamber portion and surrounding portions of the engine. In the figure, 2 is a cylinder, 4 is a cylinder head, 5 is a combustion chamber, 6 is a spark plug, 7, 8 and 9 are intake port openings,
11 and 12 are exhaust port openings, 13.14 and 1
5 is a branch intake port section, 16 and 17 are branch exhaust port sections, 28, 29 and 307 are intake valves, 39 and 40 are exhaust valves, and 50A and 5 OB are intake guide wall surfaces.

Claims (1)

[Claims] First and second intake valves are arranged on a wall surface of a combustion chamber forming a combustion chamber space at one end of a cylinder in an engine, and are arranged in sequence along the circumferential direction of the cylinder and are opened and closed, respectively, by a plurality of intake valves. A second and third intake port opening, and an exhaust port opening formed at a position facing the first, second and third intake port openings and opened and closed by an exhaust valve are arranged. and a peripheral edge portion of the first intake port opening at a position between the exhaust port opening and the first intake port opening adjacent to the exhaust port opening on the wall surface of the combustion chamber. A first intake guide wall surface protruding inside the combustion chamber space is provided along the combustion chamber wall surface, and the first intake port opening in the combustion chamber wall surface portion and the first intake port opening adjacent to the first intake port opening are provided along the combustion chamber wall surface. A second intake guide wall surface that protrudes inside the combustion chamber space along the peripheral edge of the second intake port opening is provided at a position between the second intake port opening and the second intake port opening. The combustion chamber structure of a multi-valve engine is designed to form.