JPS60224921A - Combustion chamber for two suction valve type internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent a swirl inside a combustion chamber from colliding with a suction valve as well as to secure combustion stability by a light load range, by situating a valve set of a suction valve at the primary suction port side in a position yet nearer to the piston side than a valve seat of another suction valve at the secondary suction port side. CONSTITUTION:A primary suction port 9a is formed into helical form to produce a swirl, while a secondary suction port 9b is formed into straight form to heighten charging efficiency. In this case, a valve seat 8a at the primary suction port 9a is situated in a position yet nearer to the piston side, namely, the side of a combustion chamber 5 than a valve seat 10b of a suction valve 8b at the secondary suction port 9b side. Now, at a light load range of an engine, a swirl immediately after entering the combustion chamber 5 from the primary suction valve 8a flows along a wall surface of the combustion chamber 5, and is going to collide with a valve head part 14b of the secondary section valve 8b situated in the adjacent position. With this constitution, a swirl quantity for colliding with the valve head part 14b is reducible.

Description

[Detailed description of the invention] Kosato Ko! The present invention relates to a combustion chamber of a two-intake valve internal combustion engine having two intake valves for one cylinder.

It is already known that Saramai Ibarao internal combustion engines are equipped with a plurality of intake valves for each cylinder in order to improve the volumetric efficiency of intake air (for example, Japanese Patent Laid-Open No. 58-197420, Japanese Patent Laid-Open No. 197420) (Sho 59-25015, etc.). In addition, in an internal combustion engine that has two intake boats and an intake valve connected to them, one intake boat has a helical port and the other It is also known that the straight port is formed from a straight boat, and the straight port side is closed by a flow control valve in the light load range (for example, Japanese Patent Laid-Open No. 58-28511). Additionally, in order to obtain a stronger swirl (swirling flow) during light loads, a combustion chamber with a nonquish region has been proposed (for example, Utility Model Application No. 59-17222, Utility Model Application No. 59-2293).
7 or Japanese Patent Application No. 58-3022 filed by the present applicant.
6 No. 5 Utility Application No. 193566, 1983).

In this type of internal combustion engine, if the two intake valves are particularly close to each other, in a light load range, immediately after the swirling flow due to the helical port exits the intake valve, the other adjacent intake valve, which is also in the lift state, It collides with the valve body of the valve, creating resistance to the flow and making it difficult to maintain a strong swirling flow.

An object of the present invention is to prevent the strong swirling flow entering the combustion chamber from the intake valve of a helical boat from being influenced by the other adjacent intake valve, especially in the light load range, and to prevent high swirl. An object of the present invention is to provide a combustion chamber for a two-intake valve type internal combustion engine that secures combustion stability in a light load range by ensuring a good flow (flow) and improves emissions and fuel efficiency.

In order to achieve these objectives, the present invention provides a helical-shaped primary intake boat for generating swirl, and a secondary intake boat equipped with a flow control valve that is opened and closed according to engine operating conditions. In a two-intake valve type internal combustion engine having an intake boat, 1
A combustion chamber for a two-intake valve internal combustion engine is provided, wherein the valve seat of the secondary intake boat-side intake valve is located closer to the piston than the valve seat of the secondary intake port-side intake valve. Even when the secondary intake boat-side intake valve is at its maximum lift, the valve end surface does not protrude further toward the piston than the valve seat outlet surface of the primary intake boat-side intake valve, or even if it does, the amount of protrusion is limited. It is desirable that the lift amount is less than half of the maximum lift amount of the primary intake boat side intake valve.

In Ohfunetan Figures 1 and 2, 1 is a cylinder block;
2 is the cylinder, 3 is the piston, 4 is the cylinder head, 5
is a combustion chamber, 6 is a spark plug, and 8a.

8b is a pair of intake valves arranged adjacent to each other; 9a;
9b is the intake boat, lOa, 10b is the valve seat of the intake valve,
lla and llb are a pair of exhaust valves arranged adjacent to each other, and 12a and (12b) are exhaust boats.

As shown in FIG. 2, the first intake port) 9a has a swirling flow (
On the other hand, the second intake port 9b is configured as a straight port to increase filling efficiency.
b is provided with a flow rate control valve 13. The flow rate control valve 13 is controlled to open and close by a control device (not shown), and is driven to close the straight port 9b in a light load range or a low rotation range.

In Figure 3, the primary intake boat (or helical boat) 9
The valve seat 10a of the intake valve 8a on the a side is located closer to the piston 3 (combustion chamber 5) than the valve seat 10b of the intake valve 8b on the side of the secondary intake boat, that is, the straight port 9b. In this case, when the secondary intake boat 9b side intake valve 8b is at its maximum lift, its valve shank 14b end face (position of surface A) is in contact with the valve seat outlet face (B) of the intake valve 8a on the 9a side.
It can be prevented from protruding further toward the piston 3 (combustion chamber 5) than the surface position). Alternatively, even if it protrudes a little, the amount of protrusion α should be less than half of the maximum lift amount β of the air valve 8a on the side of the primary intake boat 9a, as shown in FIG.

The primary intake valve 8a and the secondary intake valve 8b open and close at approximately the same timing or at the same time, and with approximately the same lift amount or exactly the same lift amount.As mentioned above, in the light load range of the engine Since the flow rate control valve 13 is closed, most of the air-fuel mixture flows from the primary intake boat (helical bow) 9a to the combustion chamber 5, generating a strong swirling flow. 1
Since the swirling flow immediately after entering the combustion chamber 5 from the secondary intake valve 8a tends to flow along the wall surface of the combustion chamber 5, the valve shank portion 14 of the adjacent secondary intake valve 8b, which is just open,
However, in the present invention, the valve seat 10a on the primary intake valve 8a side is located closer to the piston 3 (combustion chamber 5) than the valve seat 10b on the secondary intake valve 8b side, so the secondary intake valve 8b The amount of impact on the valve shank portion 14b is extremely small, so it is possible to maintain the rotational strength without losing the turning energy.

In the middle and high load range of the engine, the flow control valve 13 opens, so the air-fuel mixture flows through the primary intake bow) 9a and the secondary intake port).
9a into the combustion chamber 5.

Note that the number of exhaust valves 10a, 10b does not necessarily have to be two, and may be one. Regarding the relationship between the primary intake valve 8a and the exhaust valves 10a and 10b, if the exhaust valve is relatively close to the primary intake valve 8a, the valve seat of the primary intake valve 8a is closer than the valve seat of the exhaust valve. It is desirable to arrange the valve 10a so that it is on the piston side, but since the exhaust valve is normally open when the intake valve is open, the difference in level may be smaller than the relationship between a pair of intake valves.

Also, high swirl can be maintained in the light load range.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the combustion chamber of a two-intake valve internal combustion engine taken along line 1-1 in Figure 2, and Figure 2 is a cross-sectional view taken along line ■-■ in Figure 1, showing the combustion chamber as a cylinder. FIG. 3 is a cross-sectional view taken along line m-■ (a plane including the axis of the intake valve) in FIG.・・Intake valve, 9a, 9b・
...Intake port, 10a, 10b...Valve seat, 13.
...Flow rate control valve, 14a, 14b --- Valve bulk part, 8... Valve bulk end surface of intake valve 8b at maximum lift, B.
...Outlet surface of the valve seat 10a, α...Protrusion amount, β...Maximum lift amount of the intake valve 8a. Patent applicant Toyota Motor Corporation Patent agent Akira Aoki Patent attorney Kazuyuki Nishidate Patent attorney Soto Higuchi Patent attorney Akira Yamaguchi Patent attorney Masaya Nishiyama Figure 1 3

Claims (1)

[Claims] 1. A two-intake valve internal combustion engine having a helical primary intake boat for generating swirl and a secondary intake boat equipped with a flow rate control valve that is opened and closed according to engine operating conditions. A combustion chamber of a two-intake valve type internal combustion engine, wherein the valve seat of the primary intake boat-side intake valve is located closer to the piston than the valve seat of the secondary intake boat-side intake valve. 2. Claims characterized in that the secondary intake boat-side intake valve does not have its valve bulk end surface protruding further toward the piston than the valve seat outlet surface of the primary intake boat-side intake valve even at its maximum lift. The combustion chamber described in paragraph 1. 3. When the secondary intake boat-side intake valve is at its maximum lift, the end face of its valve bulk protrudes toward the piston side beyond the valve seat end face of the primary intake boat-side intake valve, but the amount of protrusion is smaller than that on the primary intake boat side. The combustion chamber according to claim 1, characterized in that the lift amount is less than half of the maximum lift amount of the intake valve.