JPH0410337Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a helical intake port that generates a swirl flow of intake air within a combustion chamber of an internal combustion engine.

[Conventional technology]

A helical intake port has an opening to the combustion chamber formed in a spiral shape to generate a swirl flow of intake air within the combustion chamber, and this swirl flow improves combustion. However, when the engine is running at high speed and under high load, the special shape of the opening as described above tends to increase intake resistance and reduce filling efficiency. To solve this problem, we proposed a helical intake port, which has a branch path separate from the intake passage that generates the swirl flow, and supplies intake air from this branch path when the engine is running at high speeds and under high load to increase filling efficiency. (Unexamined Japanese Patent Publication No. 58-23224)
(see publication).

Furthermore, especially in direct injection diesel engines, air flow within the combustion chamber has an important influence on combustion. In this type of diesel engine, the movement given to the air by the intake system includes the macroscopic swirl flow as described above and the microscopic turbulence flow, and this turbulence is especially caused by the injected fuel and air. Not only does it affect the mixing with the fuel, but it is also an important factor regarding late combustion. Therefore, a proposal for providing this turbulent flow is disclosed in Japanese Patent Publication No. 12016/1983.

[Problem that the invention attempts to solve]

According to the means disclosed in the above-mentioned Japanese Patent Publication No. 57-12016, the collision between the swirl flow and the flow in the opposite direction to generate the turbulent flow occurs at a distance after the intake valve outflow. There is a problem in that the generation force is weak and the flow is forced to change, which increases the air flow resistance.

[Means for Solving the Problems] According to the present invention, the above problems are solved in a helical port having an intake passage having a spiral portion and a branch passage partitioned from the intake passage by a partition wall. This problem is solved by making special arrangements for the position of the end of the path and between this end and the end of the spiral. That is, the measures taken to solve the above-mentioned problems in the present invention are as follows: a spiral portion formed around the intake valve; an intake inlet passage connected tangentially to the spiral portion and extending almost straight; and a spiral portion formed around the intake valve. It is composed of a branch passage which is branched from the inlet passage part by a partition wall provided in the guide part of the shaft and communicates with the spiral terminal part of the spiral part, and the ceiling of the spiral part gradually opens into the combustion chamber while reaching the spiral terminal part. In a helical intake port configured such that the ceiling of the branch passage descends rapidly toward the intake valve head, the terminal end of the branch passage is set so that the terminal end of the branch passage is lower than the spiral portion with respect to the intake valve shaft. A partition wall is provided that projects outwardly and projects toward the opening to the combustion chamber between the spiral end portion and the branch path end portion.

[Effect]

According to the present invention, the intake air flowing from the intake inlet passage is divided into the main stream flowing into the vortex part and the side stream flowing through the branch passage, and the main stream flowing through the volute part flows into the cylinder internal combustion engine to create a macroscopic swirl flow. cause On the other hand, the side flow flowing through the branch path becomes a sharp downward flow near its terminal end, but this terminal end protrudes outward from the spiral terminal end with respect to the intake valve shaft, and there is a partition wall between them. Due to the presence of the swirl flow, the swirl flow flows outside the intake valve without interfering with the swirl flow.
Since the mainstream swirl flow exists around the intake valve, the downward flow, which is the side flow, collides with this swirl flow in this area, causing microscopic turbulence.

In this way, the macroscopic swirl flow required for combustion does not lose its momentum, and in addition to this swirl flow, a side flow flows in, increasing the volumetric efficiency, especially when the engine is at high speed and under high load. increase
In addition, this swirl flow creates strong microscopic turbulence due to the interaction with the side flow, which persists until the combustion process, which promotes combustion and improves output, especially at low speeds in engines where swirl flow tends to be insufficient. .

〔Example〕

Examples of the present invention will be described below with reference to the drawings.

Referring to FIGS. 1 to 3, 1 is a cylinder head, 2 is a cylinder bore (combustion chamber), 3 is an axial center of an intake valve (not shown), and 4 is an intake inlet passage. A partition wall 31 having a triangular horizontal cross section and projecting downward is provided on the guide portion of the intake valve shaft.
It is divided into a branch road 6. The spiral passage 5 has a spiral part 51 around the intake valve shaft, and as shown in FIG. 2, this spiral part 51 gradually extends from the intake inlet passage 4 toward the spiral end end 52 (FIG. 1). It has a ceiling portion 53 that descends. Branch passage 6 is intake inlet passage 4
It extends almost straight from the center to reach the inside of the combustion chamber 2, and communicates with the spiral end portion 52. As shown in FIG. 2, this branch passage 6 has a ceiling 61 that is continuous with the ceiling of the intake passage 4 and steeply descends toward an intake valve umbrella (not shown). Also, the terminal end 6 of the branch road 6
As shown in FIG. 1, reference numeral 2 extends outward from the spiral end portion 52 by a distance h with respect to the center 3 of the intake valve shaft, and is directed toward the center 21 of the combustion chamber. Furthermore, as shown in FIGS. 2 and 3, a terminal end partition wall 7 that projects toward the combustion chamber 2 is provided between the spiral terminal end 52 and the branched passage terminal end 62.

The operation of this embodiment configured as described above will be explained.

Fresh air sucked in from an intake manifold (not shown) passes through the intake inlet passage 4 and is passed through the partition wall 31.
The swirl flow is divided into a main flow a flowing through the swirl passage 5 and a side flow b flowing through the branch passage 6. The main flow a flowing through the swirl passage 5 flows into the cylinder through a gap between an intake valve head portion and a valve seat portion (not shown), as in a normal helical intake port, and becomes a swirl flow a′. On the other hand, the side stream b tries to flow into the combustion chamber 2 through the space between the intake valve head and the valve seat like the main stream a, but the branch passage 6 has its terminal end 62 at the center of the valve shaft 3. Since the spiral end portion 52 and the branch path end portion 62 are provided with a terminal partition wall 7, the swirl flow a flowing through the spiral end portion 52 is and ceiling 6 of branch road 6
1 flows into the combustion chamber 2 from the intake valve without interfering with the rapid downward flow b' flowing along the intake valve. Therefore, the macroscopic swirl flow generated in the combustion chamber 2
The swirl flow required for combustion is maintained in a' without being damaged by the side stream b. Furthermore, in addition to this swirl flow a', a side flow b flows in, so the volumetric efficiency inside the combustion chamber 2 increases, and the output is increased without reducing the amount of air at high engine speeds and high loads, which is a problem with helical intake ports. increase

Further, the swirl flow a flowing out from the intake valve exists around this intake valve, and in this area, the swirl flow a collides with the rapid downward flow b' of the side flow,
Generates strong microscopic turbulence c. This turbulence c
Since this lasts until the combustion stroke, combustion is promoted especially at low engine speeds where swirl flow tends to be insufficient, improving output torque at low speeds. In addition, since the combustion speed becomes faster due to the generation of the turbulent flow c mentioned above, the fuel injection timing can be delayed, and there is less increase in smoke, which would normally be a problem.
Can reduce NOx emissions.

[Effect of idea]

According to the present invention, microscopic turbulence, which has an important relationship with the mixing of sprayed fuel and air and late-stage combustion, can be efficiently obtained and this continues until the combustion stroke.
In particular, combustion is promoted at low engine speeds where swirl flow tends to be insufficient, and output torque is increased.
In addition, by increasing the combustion speed, it is possible to delay the fuel injection timing, which reduces the increase in smoke.
This will reduce NOx emissions.

Furthermore, it is possible to avoid the obstruction of the swirl flow due to the occurrence of the turbulent flow, the swirl flow necessary for combustion is secured, and in addition to this swirl flow, another intake air flows from the branch path, so the inside of the combustion chamber is The volumetric efficiency is increased, and the high power required especially when the engine is operated at high speed and high load can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a plan view of an embodiment of the present invention, and Fig. 2 is a plan view of an embodiment of the present invention.
A vertical sectional view taken along the line - in the figure, and FIG. 3 is an enlarged perspective view of the same embodiment. 1... Cylinder head, 2... Cylinder bore (combustion chamber), 3... Intake valve shaft center, 31... Partition wall,
4... Intake inlet passage, 5... Spiral passage, 51...
Spiral part, 52... Spiral end part, 53... Spiral part ceiling, 6... Branch road, 61... Branch road ceiling, 62...
... Branch road end part, 7... End part bulkhead.

Claims (1)

[Scope of utility model registration request] A spiral portion formed around the intake valve, an intake inlet passage portion that is tangentially connected to the spiral portion and extends almost straight, and a partition wall provided in the guide portion of the intake valve shaft that branches from the inlet passage portion. The ceiling of the spiral part gradually descends toward the combustion chamber while reaching the spiral end part, and the ceiling of the branch passage connects to the intake valve head part. In a helical intake port configured to descend rapidly, the terminal end of the branch passage is made to protrude outward from the spiral part with respect to the intake valve shaft, and the terminal end of the branch passage is arranged such that the terminal end of the branch passage extends outward from the spiral part, and the terminal end of the branch passage extends outward from the spiral part with respect to the intake valve shaft. Between,
A helical intake port characterized by having a partition wall that protrudes toward the opening to the combustion chamber.