JPH034754Y2 - - Google Patents

Description

[Detailed Description of the Invention] <<Industrial Application Field>> The present invention relates to an intake device that swirls intake air of an engine in a combustion chamber to improve combustion efficiency.

《Prior Art》 Conventionally, this type of device has a swirl port in which intake air is swirled from an intake port in a swirling flow generation chamber and then flows into a combustion chamber, and a swirl port in which intake air is directly drawn tangentially into a combustion chamber from an intake port into a combustion chamber. There are two types: a direct port that generates a swirling flow.

《Problems to be solved by the invention》 However, in the swirl port, most of the intake air is swirled in the swirling flow generation chamber, so the intake resistance is large, and in order to reduce the intake resistance, the swirling flow generation chamber is formed large. Therefore, the pitch between the cylinders cannot be made sufficiently small, and the engine cannot be made smaller.

Moreover, since the inertial force of the intake air traveling straight through the intake port is converted into the inertial force of the swirling flow, the filling efficiency of the intake air into the combustion chamber is reduced accordingly.

On the other hand, with a direct port, in order to force the intake air to flow into the combustion chamber without resistance, the intake port must be formed vertically compared to a swirl port, which increases the cylinder head and the height of the engine. It gets expensive.

In addition, when the engine is operating at low speeds and low loads, the amount of air taken into the intake port decreases, so with a direct port, sufficient swirl cannot be generated in the combustion chamber, resulting in a decrease in combustion efficiency.

Furthermore, in diesel engines, in order to increase the compression ratio, a combustion chamber is formed between the bottom surface of the cylinder head and the top surface of the piston, and an intake port is placed on the bottom surface of the cylinder head opposite to the top surface of the piston. Many engines open in parallel to make the combustion chamber smaller, and the challenge is to develop an intake port shape that can increase the direct component and improve charging efficiency for those with this structure.

The present invention was proposed in order to solve the above problems and achieve the above objects.The present invention is designed to generate a strong swirling flow by swirling the intake air flowing through the outer circumferential wall of the intake passage in a swirling flow generation chamber. ,
By directly allowing a large amount of the intake air flowing through the inner circumferential wall to flow into the combustion chamber, a strong swirling flow is generated in the combustion chamber, and at the same time, the direct component is increased, making it possible to downsize the engine while improving combustion efficiency. The goal is to improve charging efficiency and improve engine output.

《Means for solving the problem》 In order to solve the problem, the present invention, for example,
As shown in Figures 3 to 3, a combustion chamber 7 is formed between the lower surface 6a of the cylinder head 6 and the top surface 4a of the piston 4, and an intake port 12 is formed on the lower surface 6a of the cylinder head opposite to the piston top surface 4a. Piston top surface 4
A swirling flow generation chamber 13 is formed above the intake port 12, and the outer circumferential wall 8a at the tip of the intake passage 8 is tangentially connected to the swirling flow generation chamber 13. The shape of the inner circumferential wall 8b of the section is such that a virtual extension line _L1 extending from the opening 8c at the tip thereof is closer to the center P than the peripheral edge of the intake port 12.
The bottom wall 8d of the air intake passage 8 is shaped so as to pass through the portion closer to the side, and the shape of the bottom wall 8d of the air intake passage 8 is
is formed parallel to the lower surface 6a of the cylinder head, and as it approaches the distal end from the base end 18,
An end 19 of the bottom wall 8d on the inner circumferential wall 8b portion side is formed into an inclined surface that gradually approaches the lower surface 6a of the cylinder head than an end 20 on the outer circumferential wall 8a portion side, and the bottom wall 8d of the intake passage 8 and the inner circumferential wall 8b portion are formed into an inclined surface. The ridge line 15 formed by the cylinder head is formed so that it gradually approaches the lower surface 6a of the cylinder head as it goes from the base end 18 to the distal end, and the virtual extension line _L2 of the ridge line 15 is the inlet port 12.
It is characterized in that it is formed so as to enter the combustion chamber 7 side further than the opposite end edge 12a and to be connected to the combustion chamber 7 in a tangential manner.

"Example" Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a front view of the main parts of a vertical water-cooled diesel engine.
are integrally formed.

The upper end opening of the cylinder 5 is covered by a cylinder head 6, and a combustion chamber 7 is formed between the upper surface 4a of the piston 4 and the lower surface of the cylinder head 6.

This combustion chamber 7 is communicated with an air cleaner (not shown) through an intake passage 8 formed in the cylinder head 6, and with a muffler (not shown) through an exhaust passage 10. Communication with the passage 10 is interrupted by an intake valve 11 and an exhaust valve 9.

As shown in FIGS. 2 and 3, the intake passage 8 has an intake port 12 on the upper surface of the combustion chamber 7 (lower surface 6a of the cylinder head) parallel to the piston top surface 4a, and creates a swirling flow in the upper part of the intake port 12. A chamber 13 is formed,
An intake passage 8 extends from the swirling flow generation chamber 13.

The outer circumferential wall 8a at the tip of the air intake passage 8 is formed tangentially to the swirling flow generation chamber 13, and the inner circumferential wall 8b at the tip is formed so that the imaginary extension line _L1 from the opening 8c at the tip is the intake port 12. The proximal end portion 1 of the air intake passage 8 is formed so as to be closer to the center P of the
The bottom wall 8d of the cylinder head 8 is formed parallel to the lower surface 6a of the cylinder head, and the bottom wall 8d between the base end 18 and the tip end
is formed into an inclined surface whose end 19 on the inner peripheral wall 8b portion side is closer to the cylinder head lower surface 6a than the end 20 on the outer peripheral wall 8a portion side, and furthermore, the bottom wall 8d and the inner peripheral wall 8b portion The ridge line 15 formed by the above-mentioned ridge line 15 is formed so as to gradually approach the lower surface 6a of the cylinder head as it goes from the base end 18 to the distal end.
L ₂ is formed lower than the opposing edge 12a of the intake port 12 facing the opening side of the intake passage 8 so as to enter into the combustion chamber 7 side, and this imaginary extension line L ₂ and the lower surface 6a of the cylinder head 6 The angle θ is 20°±
It is set within a range of 5°.

When the intake passage 8 is formed in this way, as shown in FIGS. 4 and 5, the swirl component S of the intake air that passes through the outer circumferential wall 8a of the intake passage 8 among the air purified by the air cleaner during intake by the engine E.
is swirled in the swirling flow generating chamber 13 to become a swirling flow, and then flows into the combustion chamber 7, and flows into the inner circumferential wall 8b.
The direct component D of the intake air flowing near the end 19 on the side of the inner peripheral wall 8b of the inner peripheral wall 8b of the bottom wall 8d flows tangentially into the combustion chamber 7, and has a large linear rotation along the cylinder peripheral wall in the combustion chamber 7. Forms a strong swirling flow.

In this way, a large swirling flow generated by the direct component D of the intake air directly flowing into the combustion chamber 7 from the intake passage 8 and a swirling flow of the swirl component S formed in the swirling flow generation chamber 13 flow into the combustion chamber 7. The sprayed fuel is well mixed and completely combusted to improve the output of the engine E.

The direct component D of the intake air is generated in the swirling flow generation chamber 13.
The fuel crosses the lower part of the combustion chamber 7 and is sucked directly into the combustion chamber 7. On the other hand, the swirl component S swirls from the upper part to the lower part in the swirling flow generation chamber 13 and then enters the combustion chamber 7. Therefore, the degree of change in the intake amount with respect to the change in the negative pressure suction force V of the combustion chamber 7 is larger in the direct component D.
The swirl component S is smaller.

When the engine is operating at low speed and low load, the air intake speed is slow and the negative pressure suction force V of the combustion chamber 7 is small. For this reason, while the air intake rate relative to the volume of the combustion chamber 7, the direct component D, decreases, the swirl component S increases. As a result, a large amount of swirl components generates a strong swirling flow within the combustion chamber 7, improving mixing performance, improving combustion performance, and reducing fuel consumption rate.

During high-speed, high-load operation of the engine, the air suction speed is fast and the negative pressure suction force V of the combustion chamber 7 is large. Therefore, while the air intake rate relative to the volume of the combustion chamber 7 increases for the direct component D, it decreases for the swirl component S. As a result, a large amount of the direct component D is sucked into the combustion chamber 7 at a high speed, causing a strong swirling flow within the combustion chamber 7, improving the mixing performance and reducing the fuel consumption rate, and on the other hand, filling the combustion chamber 7. Increase efficiency and increase output.

《Effects of the invention》 As mentioned above, the present invention has the effect that when the engine is operating at low speed and low load, the air intake rate of the swirl component increases, and a large amount of the swirl component creates a strong swirl inside the combustion chamber. Since the flow is generated and the mixing performance is improved, the fuel consumption rate can be reduced.

Moreover, during high-speed, high-load operation, the air intake rate of the swirl component increases, so a large amount of the direct component with high speed creates a strong swirling flow inside the combustion chamber, improving mixing performance and reducing fuel consumption. On the other hand, the filling efficiency can be increased and the output can be increased.

Moreover, in the case of a swirl port in which all of the intake air is swirled in the swirl flow generation chamber, the swirl flow generation chamber must be made large in order to increase the filling efficiency, whereas in the present invention, a portion of the intake air is Since the charging efficiency is increased by drawing air directly into the combustion chamber, the swirling flow generation chamber can be made smaller, and the distance between cylinder pitches can be shortened to make the engine more compact.

In addition, in the case of a direct port that draws all of the intake air directly into the combustion chamber from the intake passage, the intake passage must be built upright in the cylinder head in order to form a good swirling flow in the combustion chamber. On the other hand, in this invention, a part of the intake air is swirled in the swirling flow generation chamber and sucked into the combustion chamber to form a swirling flow well, so the intake passage can be formed flat, and the height of the cylinder head can be lowered to make the engine more compact. can be converted into

Furthermore, in order to increase the compression ratio in a diesel engine, a combustion chamber is formed between the bottom surface of the cylinder head and the top surface of the piston, and an intake port is placed on the bottom surface of the cylinder head opposite to the top surface of the piston. Even in the case of a structure in which the bottom wall between the proximal end and the distal end of the intake passage opens in parallel to If it is formed on an inclined surface located close to the cylinder head, and the ridge line formed by the bottom wall of the intake passage and the inner circumferential wall portion gradually approaches the lower surface of the cylinder head as it goes from the base end to the tip end,
Filling efficiency can be increased by increasing the direct component. In other words, the outer peripheral wall part, which is an element that strengthens the swirl, is shaped to create a swirl at a position far from the bottom surface of the cylinder head, whereas the inner peripheral wall part, which does not contribute much to swirl, has a bottom wall that gradually approaches the bottom surface of the cylinder head. This is because the shape is such that the direct component D can be increased. In particular, even when the engine is small and requires a swirl component, the present invention can achieve both a strong swirl and an increase in the direct component.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which FIG. 1 is a longitudinal sectional front view of a vertical diesel engine, FIG. 2 is a sectional view taken along the line -- in FIG. 1, FIG. The figure is a cross-sectional plan view showing the flow of intake air, and FIG. 5 is a longitudinal front view showing the flow of intake air. 7...Combustion chamber, 8...Intake passage, 8a...Outer circumferential wall of 8, 8b...Inner circumferential wall of 8, 8c...8
opening, 8d...bottom wall of 8, 12...intake port,
12a... end edge of 12, 13... swirling flow generation chamber,
15...Ridge line, L ₁ /L ₂ ...Virtual extension line, P...
Center of 11, D... Direct component of intake air, S...
...Swirl component of intake air.

Claims (1)

[Claims for Utility Model Registration] A combustion chamber 7 is formed between the lower surface 6a of the cylinder head 6 and the top surface 4a of the piston 4, and an intake port 12 is provided on the lower surface 6a of the cylinder head opposite to the piston top surface 4a. The air intake port 1 opens parallel to the surface 4a.
A swirling flow generation chamber 13 is formed in the upper part of the intake passage 8, and the outer circumferential wall 8a at the tip of the intake passage 8 is tangentially connected to the swirling flow generation chamber 13.The shape of the inner circumference wall 8b at the tip of the intake passage 8 is , the virtual extension line _L1 extending from the opening 8c at the tip of this is closer to the center P than the peripheral edge of the intake port 12.
The bottom wall 8d of the air intake passage 8 is shaped so as to pass through the portion closer to the side, and the shape of the bottom wall 8d of the air intake passage 8 is
is formed parallel to the lower surface 6a of the cylinder head, and as it approaches the distal end from the base end 18,
An end 19 of the bottom wall 8d on the inner circumferential wall 8b portion side is formed into an inclined surface that gradually approaches the lower surface 6a of the cylinder head than an end 20 on the outer circumferential wall 8a portion side, and the bottom wall 8d of the intake passage 8 and the inner circumferential wall 8b portion are formed into an inclined surface. The ridge line 15 formed by the cylinder head is formed so that it gradually approaches the lower surface 6a of the cylinder head as it goes from the base end 18 to the tip end, and the imaginary extension line _L2 of the ridge line 15 is longer than the opposite end edge 12a of the intake port 12. An engine intake device characterized by being formed to enter into the combustion chamber 7 side and to be connected tangentially to the combustion chamber 7.