JPH063148Y2 - 4-valve engine cylinder head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a cylinder head of a DOHC four-valve engine, and more particularly to an improvement of a cylinder head capable of improving its swirl ratio. It is about.

(Prior Art) A cylinder head of a four-valve engine includes a head body having a combustion chamber in which fuel is injected from a fuel injection nozzle, two intake ports for supplying air to the combustion chamber, and two exhaust ports for exhausting the combustion chamber. And an intake valve and an exhaust valve that open and close the openings of the intake port and the exhaust port, respectively. In the prior art, the two intake ports and the two exhaust ports are located on a plane where a line connecting the central axis lines of the openings of these intake ports and a line connecting the central axis lines of the openings of the exhaust ports pass through the central axis line of the fuel injection nozzle. They are arranged in parallel. Generally, in order to increase the swirl ratio of the engine (the swirl rotational speed n _s / the engine rotational speed n), the intake port is directed tangentially, or the opening of the intake port is made spiral. However, in a 4-valve engine, the two intake ports are close to each other, so there are restrictions on the direction of the intake port and the shape of the opening. Therefore, the swirl ratio cannot be increased. Therefore, increase the swirl strength to the optimum value. There was a drawback that I could not.

(Object of the Invention) An object of the present invention is to provide a cylinder head of a four-valve engine capable of optimizing the swirl strength.

(Structure of the Invention) A cylinder head of a four-valve engine according to the present invention includes a head body having a combustion chamber for injecting fuel from a fuel injection nozzle, two intake ports for supplying air to the combustion chamber, and a combustion chamber. It consists of two exhaust ports for exhausting from, and two intake valves and exhaust valves for opening and closing the openings of these intake ports and exhaust ports, respectively, and the valve rods of the two intake valves penetrate the head body upward. Driven by two intake valve cams that are rotated by a common cam shaft, and the valve rods of the two exhaust valves are for the two exhaust valves that pass through the head body upward and are rotated by a common cam shaft. In a cylinder head of a four-valve engine driven by cams, the two intake ports have a line connecting the central axes of the openings of the intake ports with the central axis of the fuel injection nozzle. The intake rods are arranged so as to be inclined with respect to a plane parallel to the plane that passes through the line, and the valve rods of the two intake valves are intake so that the tops thereof respectively engage with the two intake valve cams on the common cam shaft. It is characterized in that the line connecting the tops of the valve rods of the valve is arranged in the parallel plane.

According to this structure, the openings of the intake ports of the two intake valves are arranged side by side in the swirl direction that forms the swirl in the combustion chamber to strengthen the swirl, and therefore the swirl rotation speed can be increased, so the swirl ratio can be increased. Can be increased to optimize swirl strength.

Embodiment An embodiment of the present invention will be described in detail with reference to the drawings. FIGS. 1 and 2 show a cylinder head 10 of a DOHC four-valve engine according to the present invention.
Is a combustion chamber 1 in which fuel is injected from a fuel injection nozzle 12.
Head body 16 having four, two intake ports 18 and 18 'for supplying air to the combustion chamber 14, and the combustion chamber 14
From the two exhaust ports 20 and 20 'and two intake valves 22 and 22' for opening and closing the openings of the intake ports 18 and 18 'and the exhaust ports 20 and 20', respectively.
And exhaust valves 24, 24 '(22', 24 'are not shown)
And consists of. The two intake valves 22 and 22 ′ have valve rods 34 and 34 ′ which penetrate the head body 16 upward and are driven by two intake valve cams 30 and 30 ′ rotated by a common cam shaft 26, respectively. . Also, 2
The two exhaust valves 24, 24 'have valve rods 36, 36' respectively penetrating upwardly through the head body 16 and driven by two exhaust valve cams 32, 32 'rotated by a common cam shaft 28.

The two intake ports 18, 18 'are these intake ports 1
The line X connecting the central axes of the openings 18a, 18'a of the 8, 18 'is arranged so as to be inclined at an angle θ with respect to the plane Y parallel to the plane P passing through the central axis of the fuel injection nozzle 12.
On the other hand, the valve rods 34, 34 'of the two intake valves 22, 22' are arranged so that the line connecting the tops thereof lies in the parallel plane Y. In this way, the intake valves 22, 22 '
The intake valve cam on the cam shaft 26 common to the tops of the valve rods 34, 34 'of the intake valves 22, 22', although the two openings 18a, 18'a opened and closed by The 30, 30 'can be engaged. Angle θ is 1
It is preferably 5 ° ± 10 ° (5 ° to 25 °).

In this way, the openings 18a, 1 of the intake ports 18, 18 'are
8'a is a line X connecting the central axes of the fuel injection nozzle 12
These openings 18a, 18'a are arranged side by side in the direction of the swirl that forms the swirl in the combustion chamber 14 to intensify the swirl when slanted with respect to a plane parallel to the plane passing through the central axis of become. Therefore, intake port 1
Since the rotation speed of the swirl generated by the air supplied into the combustion chamber 14 from 8, 18 'can be increased, the swirl ratio can be increased and the swirl strength can be optimized.

In the embodiment shown, the two exhaust ports 20, 20 'also follow the intake ports 18, 18'.
A line X'connecting the central axes of the openings 20a, 20'a of 20 '
Are arranged so as to be inclined at the same angle with respect to the plane Y parallel to the plane passing through the center axis of the fuel injection nozzle, and in this case also, the valve rods 36 and 36 'of the exhaust valves 24 and 24' connect the tops thereof. The lines, that is, the axes of the camshafts 28 are arranged in a plane Y parallel to each other.

(Effect of the Invention) According to the present invention, as described above, since the swirl rotation speed can be increased, the swirl ratio can be increased to optimize the swirl strength, and the swirl ratio can be increased. Even if the two intake ports are displaced, the two intake valves can be driven by the cam on the common cam shaft. Therefore, the swirl strength is optimized with a simple structure without complicating the drive system of the intake valves. There is a real benefit that can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 are a top view and an enlarged sectional view of a cylinder head of a four-valve engine according to the present invention. 10 ... Cylinder head, 12 ... Fuel injection nozzle, 14 ...
Combustion chamber, 16 ... Head body, 18, 18 '... Intake port, 20, 20' ... Exhaust port, 22, 22 '... Intake valve, 22a, 22'a ... Valve rod, 26 ... Cam shaft, 30, 3
0 '... intake valve cam.

Claims (3)

[Scope of utility model registration request] 1. A head body having a combustion chamber for injecting fuel from a fuel injection nozzle and air for supplying 2 to the combustion chamber.
One intake port, two exhaust ports exhausting from the combustion chamber, and two intake valves and exhaust valves respectively opening and closing the openings of the intake port and the exhaust port.
The valve rods of the two intake valves are respectively driven by two intake valve cams that pass through the head body upward and are rotated by a common cam shaft, and the valve rods of the two exhaust valves face the head body upward. In a cylinder head of a four-valve engine that is driven by two exhaust valve cams that pass through each other and are rotated by a common cam shaft, the two intake ports have a line connecting the central axes of the openings of these intake ports. The fuel injection nozzle is arranged so as to be inclined with respect to a plane parallel to a plane passing through the central axis of the fuel injection nozzle, and
The tops of the two intake valve rods are 2 on the common camshaft.
A cylinder head for a four-valve engine, characterized in that the lines connecting the tops are arranged so as to be respectively engaged with the three intake valve cams in the parallel planes. 2. The inclination of the line connecting the central axes is 5 ° to 2
The cylinder head of a four-valve engine according to claim 1, wherein the cylinder head has an angle of 5 °. 3. The two exhaust ports follow the intake port so that a line connecting the central axes of the openings of the exhaust ports is inclined with respect to a plane parallel to a plane passing through the central axis of the fuel injection nozzle. The cylinder head for a four-valve engine according to claim 1 or 2, wherein