JPS6226590Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to the improvement of the intake system of a dual-intake internal combustion engine, and in particular strengthens the horizontal flow component of the intake air flow and disturbs the intake air flow to improve combustibility.
This invention relates to an intake system for an internal combustion engine that enables improved engine stability and improved exhaust purification performance.

In a dual-intake internal combustion engine, the angle θ1 that the center of the primary intake flow from the low-load primary intake passage forms with the deck surface of the cylinder head is made small, and the primary intake passage is moved closer to the deck surface. It is preferable to do this, and by doing so, it is possible to prevent the swirl generated by the intake air flow from the primary intake passage from being crushed and extinguished by the rise of the piston during the compression stroke. Furthermore, by increasing the angle θ2 that the center of the secondary intake air flow from the high-load secondary intake passage makes with the deck surface of the cylinder head, it is possible to increase the filling efficiency in the high-load range. In other words, it is preferable that the center of the primary intake flow from the primary intake passage and the center of the secondary intake flow from the secondary intake passage be substantially perpendicular to each other.

By generating an intake swirl in the combustion chamber, it is possible to improve the combustion chamber with a so-called flame-retardant mixture such as a lean mixture or EGR.

Further, by reinforcing the horizontal flow component in the intake air flow, it is possible to easily generate a swirl that is difficult to be crushed by the piston.

Therefore, the purpose of this invention is to strengthen the horizontal component of the primary intake flow by jumping and deflecting a part of the primary intake flow toward the cylinder head, that is, to reduce the swirl pitch p.
Even during the compression stroke, the swirl is not crushed by the piston, the swirl continues until the end of the compression stroke, the flame kernel propagates ideally, the turbulent flow due to the disturbance action increases the combustion speed, improves fuel efficiency, and improves driveability. An object of the present invention is to realize an intake device for an internal combustion engine that improves air intake and contributes to reducing harmful components of exhaust gas.

Embodiments of this invention will be described below based on the drawings.

In FIG. 1, 2 is a cylinder head, 4 is a cylinder, 6 is a piston, 8 is a combustion chamber, 10 is a primary intake passage for low load, and 10c is the primary intake passage 10.
11 is the discharge opening of the primary intake passage 10, 12 is the secondary intake passage for high load,
12c is the center of the secondary intake flow from the secondary intake passage 12, 14 is the intake valve, 16 is the intake valve seat, and 1
8 is the central axis of the cylinder 4. Also, θ1 is 1
θ2 is the angle between the center 10c of the primary intake flow from the secondary intake passage 10 and the deck surface 2d of the cylinder head 2, and θ2 is the angle between the center 12c of the secondary intake flow from the secondary intake passage 12 and the deck surface 2d of the cylinder head 2. This is the angle formed with the surface 2d. Furthermore, H is the center 10c of the primary intake air flow from the primary intake passage 10 and the cylinder 4.
This is the distance from the intersection with the central axis 18 of the cylinder head 2 to the deck surface 2d of the cylinder head 2.

First, the angle θ2 formed between the center 12c of the secondary intake air flow from the high-load secondary intake passage 12 and the deck surface 2d of the cylinder head 2 is configured to be sufficiently large as in the conventional case. That is, the secondary intake passage 12 is provided close to the central axis 18 of the cylinder 4. This can increase filling efficiency. Further, the angle θ1 formed between the center 10c of the primary intake flow from the low-load primary intake passage 10 and the deck surface 2d of the cylinder head 2 is made small. That is, the primary intake passage 10 is arranged parallel to and as close as possible to the deck surface 2d of the cylinder head 2, and the center 10c of the primary intake flow and the cylinder 4
The distance H from the intersection with the central axis 18 of the cylinder head 2 to the deck surface 2d of the cylinder head 2 is made short.

As shown in FIGS. 1 and 2, a portion of the inner circumferential surface of the discharge opening 11 of the primary intake passage 10 for low load is located on the deck surface 2d side of the cylinder head 2 by a portion of the upper surface 16u of the intake valve seat 16. At the same time, the upper surface 16u of the intake valve seat 16 is oriented in the direction of the streamline of the primary intake flow in order to jump deflect a part of the primary intake flow in the direction of the cylinder head 2. A sliding portion 16j is formed to deflect the. That is, a part of the primary intake air flow interferes with the sliding portion 16j of the upper surface 16u of the intake valve seat 16 and flows into the combustion chamber 8 while being jumped in the direction of the cylinder head 2. do.

Next, the effect will be explained.

Since the primary intake passage 10 is arranged approximately parallel to the deck surface 2d of the cylinder head 2 and as close as possible, that is, the distance H is shortened, the center 1 of the primary intake flow
The angle θ1 that 0c forms with the deck surface 2d of the cylinder head 2 becomes sufficiently small, the horizontal flow component of the primary intake flow is strengthened, and an ideal intake swirl is generated in the combustion chamber 8. In other words, a small swirl of pitch p (see FIG. 3) is generated.

Furthermore, the horizontal component of the primary intake flow is further strengthened by the sliding portion 16j of the intake valve seat 16 that forms a part of the discharge opening 11 of the primary intake passage 10. That is, as shown by the broken line in FIG. 3, the primary intake air flowing into the combustion chamber 8 is directed in a direction in which a part of the flow on the deck surface 2d side of the cylinder head 2 is separated from the top surface 6t of the piston 6 by the sliding portion 16j. That is, the cylinder head is induced to jump and deflect in two directions (upward in FIG. 3). Therefore, the horizontal component of the primary intake flow that is parallel to the deck surface 2d of the cylinder head 2 is strengthened, and a swirl with a small pitch p is generated as shown by the solid line in FIG.
Further, the primary intake air flow is also subjected to a disturbance effect by the sliding portion 16j, and as a result, a swirl with a small pitch p, which is determined as a turbulent flow, can be generated in the combustion chamber 8.

In the above embodiment, a dual intake internal combustion engine has been described, but it goes without saying that this invention can also be applied to an internal combustion engine having only a single intake passage.

As is clear from the above detailed explanation, according to this invention, the angle θ1 formed with the deck surface of the cylinder head is formed small, and a part of the upper surface of the intake valve seat is used to connect the low-load primary valve to the deck surface side. A sliding portion is formed so that the upper surface of the intake valve seat faces the streamline direction of the primary intake flow so as to form a part of the inner circumferential surface of the discharge opening of the intake passage and to jump deflect a portion of the primary intake flow toward the cylinder head. This sliding part can strengthen the horizontal flow component parallel to the deck surface of the cylinder head in the intake flow from the primary intake passage and can also disturb the intake flow, as shown in Fig. 3. As the pitch p of the intake swirl becomes smaller, a turbulent flow is generated, and it is possible to prevent the swirl from being crushed and disappearing due to the rise of the piston in the compression stroke. It maintains the swirl for a long time, ideally propagates the flame kernel, increases the combustion rate, improves fuel efficiency, improves drivability, and reduces harmful components in the exhaust. It can also be achieved.

Furthermore, in the case of a dual intake engine, the angle between the center of the secondary intake air flow from the secondary intake passage and the central axis of the cylinder can be configured to be smaller than that of conventional engines, resulting in better filling efficiency. There is no inconvenience that impedes engine performance in high load ranges.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of the intake passage according to this invention.
FIG. 2 is a sectional view of the main part taken along the line - in FIG. 1, and FIG. 3 is a vertical sectional view of the cylinder illustrating the occurrence of swirl and its pitch. In the figure, 2 is the cylinder head, 2d is the deck surface, 10 is the primary intake passage for low load, and 10c is 1
The center of the secondary intake flow, 11 is the discharge opening, 12 is the secondary intake passage for high load, 12c is the center of the secondary intake flow, 1
6 is the intake valve seat, 16j is the sliding part, 16u is the upper surface of the intake valve seat, θ1 is the angle that the center of the primary intake flow makes with the deck surface, H is the intersection between the center of the primary intake flow and the central axis of the cylinder It is the distance from to the deck surface.

Claims (1)

[Scope of utility model registration request] In a dual-intake internal combustion engine that has a primary intake passage for low loads and a secondary intake passage for high loads, the angle θ1 that the primary intake passage for low loads makes with the deck surface of the cylinder head is formed to be small, and the angle θ1 of the intake valve seat is made small. A part of the upper surface forms part of the inner peripheral surface of the discharge opening of the low-load primary intake passage on the deck surface side of the cylinder head, and the intake valve is configured to jump deflect a part of the primary intake air flow toward the cylinder head. An intake device for an internal combustion engine, characterized in that a sliding portion is formed with the upper surface of the seat facing the streamline direction of the primary intake flow.