JPS5912125A - Inlet port of internal combustion engine - Google Patents

Abstract

PURPOSE:To strengthen swirl and to improve volumetric efficiency by a method wherein a helical forming angle of a helical channel in a swirl part communicating to a cylinder chamber divided and formed centering on a stem of an inlet valve and the gradient of the peak wall of the helical channel are set up within a specified range. CONSTITUTION:An inlet port comprises an introducing part 9 of inlet air and a swirl part 1 communicated to a cylinder chamber 10 centered on a valve stem A0 of an inlet valve 11. The introducing part 9 is extended from the opening end of the cylinder head 12 to the surface of a cylinder chamber 10 containing a center axis C0 displaying a gentle curve. On the other hand, the swirl part 1 is arranged from the surface containing the shaft center C0 to the valve stem center A0 and the helical channel 2 as the peripheral wall of the swirl part 1 is formed of an arc centered on the helical stem cores each exceeding two e.g. five R1-R5. Besides, the helical forming angle alpha of the swirl part 1 is formed within the range of 150-240 deg. while the gradient of the peak wall of said helical channel may be set up within the range of 0.07-0.12mm. per degree of the helical forming angle alpha from the surface containing the shaft center C0 to the valve stem center A0.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake boat for an internal combustion engine that can efficiently generate and maintain swirl in a cylinder chamber and increase volumetric efficiency.

Conventionally, an intake boat for an internal combustion engine is provided with an intake introduction part and a spiral part around the intake valve, and the top wall part of one spiral passage of the spiral part is inclined downward in order to increase the swirl in the cylinder chamber from combustion scattering. such as. There is a so-called helical intake boat.

This helical intake boat includes a lutame having the spiral portion,
You can strengthen Nuwar. However, there are technical drawbacks such as an increase in flow path loss and a decrease in volumetric efficiency.

Various methods have been tried in the past to improve this problem, but none have been found to be effective in achieving both enhanced swirl and improved volumetric efficiency.

Therefore, as a result of repeated research, the inventors of the present invention found that the spiral passage in the spiral part needs to be determined so as to increase the rate at which the intake air flowing into the intake boat is tangentially introduced into the cylinder chamber. , this is constructed with one helical axis placed eccentrically with respect to one axis, which largely depends on the inclination of the top wall of the spiral passage, and the top wall of the spiral passage is steeply sloped by P. . Such intake boat 1 is distorted because the inflow velocity distribution of intake air from the intake valve into the bore of the cylinder chamber is normally large in the center of the cylinder chamber and is tangential to the diameter (bore) of the cylinder chamber. The percentage is smaller in the peripheral areas.

In this case, the swirls formed in the cylinder chamber interfere with each other and disappear, resulting in no increase in size, and pressure loss also increases.

Therefore, based on the above findings, the present inventors constructed the top wall portion 8 of the spiral passage 2 in the spiral portion 11 as shown in the first figure. Here, we focused on the importance of the degree of inclination of the top wall portion 8 of the helical passageway 2 and the formation angle a of the helical passageway around the helical axis where the inclination exists.

The inventors conducted research with the aim of harmonizing the enhancement of swirl with the improvement of volumetric efficiency in the intake boat of an internal combustion engine, and to simplify the manufacturing as much as possible.
The present invention has been devised to solve the above-mentioned conventional problems.

That is, one aspect of the present invention is an introduction section through which intake air flows.

The cylinder head 1 of an internal combustion engine is an intake boat that is composed of a swirl section that communicates with the introduction section and is divided around the valve shaft of the intake valve and communicates with the cylinder chamber, and that creates a swirl in the intake air.
By providing this, the spiral formation angle of the spiral passage in the spiral portion is within the range of 150 degrees to 240 degrees, and the slope ratio of the top wall portion of the spiral passage is α0 per degree of the spiral formation angle.
This is an intake boat for an internal combustion engine with a slope ratio of 7M to α12U.

According to the intake bow of the present invention, the inflow velocity distribution of intake air from the intake valve into the bore of the cylinder chamber is extremely steep in the tangential peripheral portion of the cylinder chamber, and in the central portion. The proportion is small. For this reason,
The flow formed inside the cylinder chamber becomes a vortex flow along the bore, and the flow does not collide with the wall, and there is no flow interference or turbulence.

It is possible to form an overall vortex flow in the cylinder chamber and to significantly strengthen the swirl, and at the same time, the pressure loss is also small and the 1-volume efficiency can be increased.

1 to 3 show an embodiment of the present invention, in which an intake boat of an internal combustion engine has an introduction part 9 through which intake air flows, and a valve shaft A of an intake valve 11 that communicates with the introduction part 9. It consists of a spiral part 1 that passes through the cylinder chamber 10 ('S) with the center at the center.The intake boat configured in this way generates an intake swirl.

The introduction portion 9 provided in the cylinder head 11tC of the internal combustion engine extends in a gently curved shape from the open end of the cylinder head 12 to within a plane including the cylinder chamber lOD axis C0. The spiral portion 1 is arranged around the valve axis A0 of the intake valve 11 from within a plane including the axis C0 of the cylinder chamber lOO. The spiral passage 8, which is the peripheral wall of the spiral portion 1, is formed by a series of curves centered on at least two or more spiral axes. In this embodiment, there are five helical axes R+,
Rv.

R3+Ra lR6,b, and a circular arc centered on these forms the peripheral wall of the spiral passage 2. Furthermore, the spiral portion l of the intake boat has a spiral formation angle α of 2 from 150 degrees.
In this embodiment, α is approximately 178 degrees. Also.

The top wall portion 8 of the spiral passage 2 has an inclination ratio that is closer to the valve axis A of the intake valve 11 than in a plane that includes the axis C9 of the cylinder chamber 10. The angle of inclination is from α074 to 0.12 fl for each degree of the helix formation angle α, and in this embodiment, the slope is approximately α1 per degree.

The intake boat of the internal combustion engine of this embodiment having the above configuration is as follows:
Intake air introduced into the cylinder chamber 10 is passed through the spiral passage 2 of the swirl chamber 1 from the introduction part 9 to the top wall 8 of the spiral chamber 1.
It flows stably and smoothly with a predetermined slope.

(The intake air flowing through the spiral flows along the peripheral wall of the spiral passage 2 due to centrifugal force.

According to the intake boat #99 of this embodiment, the inflow velocity distribution of intake air from the intake valve into the bore of the cylinder chamber 10 is tangential to the bore of the cylinder chamber 10. 1 trowel extremely large.

The flow formed in the chamber 10 becomes a general vortex flow along the bore 1, which can significantly strengthen the swirl.

In addition, the pressure loss caused by the intake boat in the one-dormitory example is due to the pressure loss in the spiral passage 2 of the intake air and the collision of flow channels in the cylinder chamber, etc. As shown, the volumetric efficiency can be increased by a small amount.

Here, based on FIG. 8 and FIG. 4, there is a tendency for the intake air to be increased in this embodiment, and it becomes almost constant above 160 degrees.

On the other hand, the pressure loss at the port tends to increase rapidly when the temperature exceeds 220 degrees. From this figure 4, the spiral formation angle α is preferably 150 degrees to 940 degrees, especially 150 degrees.
A range of degrees to 919 degrees is good.

Next, the optimum value of the slope of the top wall portion 8 is also related to the angle a, and when the angle a is 150 degrees to fA40 degrees, α07M/1 degree to α1
A slope of 1110/1 degree is good. From this slope.

If it is small, the part indicated by the symbol AK in Fig. 1 becomes wide, and the flow does not draw a spiral but flows directly into the V 11 chamber 1.
0, the swirl decreases and the flow n interferes within the cylinder chamber, increasing pressure loss. If the inclination is greater than this, the portion indicated by A becomes narrower and the flow flows into the spiral portion l.

Although it increases swirl, it also leads to an increase in flow path loss. Therefore, the angle α is approximately αIH/1 degree 1
By making this selection, it is possible to satisfy the swirl ratio and volumetric efficiency required of the engine.

As described above, in the intake J-t of the internal combustion engine of the present invention, the spiral forming angle in the spiral passage t of the spiral portion is within the range of 150 degrees to 240 degrees, and the slope ratio of the top wall portion is set to the spiral forming angle 1. By configuring the angle of inclination from α07fi to α12 per degree, it is possible to harmoniously achieve both swirl reinforcement and volumetric efficiency improvement.

Therefore, the present invention has many practical effects such as increasing the output of the internal combustion engine and improving fuel efficiency.

[Brief explanation of drawings]

1 to 4 show an embodiment of the present invention,
FIGS. 1 and 2 are a cross-sectional view and a plan view thereof, and FIGS. 8 and 4 are diagrams showing the relationship between the angle α and the tilt angle, the swirl ratio, and the pressure loss, respectively. In the figure 1... Spiral section 2... Spiral passage 8
...Top wall part 10...Cylinder chamber 11...
...Intake valve 9...Introduction Patent applicant Toyota Central Research Institute Co., Ltd. Patent attorney Yoshiyasu Takahashi (2 others), -145- --8

Claims (1)

[Scope of Claims] An intake boat that generates a vortex in the intake air, which is composed of an introduction part through which intake air flows, and a swirl part that communicates with the introduction part and is partitioned around the valve shaft of an intake valve and communicates with one cylinder chamber. are provided in groups in the cylinder head of an internal combustion engine, and the spiral formation angle of the spiral passage in the spiral chamber is within the range of 150 to 240 degrees, and the slope ratio of the top wall of the spiral passage is set per 1 degree of the spiral formation angle. α071
An intake boat for an internal combustion engine, characterized in that it has a degree of inclination from 11 to 12 layers.