JPS6116228A - Suction device for multivalve type engine - Google Patents

Abstract

PURPOSE:To aim at improvements in combustibility in time of low load with a simple structure, by forming at least one unit, among plural suction ports being opened to one combustion chamber, into a swirl port in type and setting up it in a specific position, while bending a suction passage to some extent. CONSTITUTION:Two suction ports 4a and 4b are formed respectively in each combustion chamber 3 in case of plural cylinders, while a suction valve 6 is set up in each of these suction ports 4a and 4b. In this case, one side suction port 4a is made to open toward the tangential direction of a cylinder and to be formed into a swirl port leading air into the tangential direction, while it is set up on an almost nearly extension line of the center axis of a suction passage 9. And, a suction manifold 8 is formed in bend so as to cause its curvature center to be situated at the opposite side to the other side suction port 4b looking from the suction port 4a. With this constitution, suction dynamic pressure is given to the swirl port 4a, and a suction swirl is formed up without installing a complex valve mechanism and a control system, thus combustibility in time of low load is well improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an intake system for a multi-valve engine.

[Prior art]

In recent years, various types of automobile engines have been developed that efficiently supply intake air to the engine from the perspective of improving engine operating efficiency.One example is the intake system for multi-valve engines. It is being That is,
This allows multiple intake ports to be opened to one combustion chamber, and an intake valve is placed in each intake port to supply intake air from multiple intake ports to improve charging efficiency. This is designed to increase the output power of the engine.

By the way, this multi-valve engine intake system is advantageous in that it can achieve high output during high-load operation with a large amount of intake air, but due to its structure, the intake flow rate is slow during low-load operations with a small amount of intake air. There is a problem in that flammability decreases, leading to deterioration in fuel efficiency and emissions.

Therefore, in order to solve the above-mentioned problems, in the conventional intake device of this type, at least one of the plurality of intake ports is
One is formed as a swirl port, while a blockage valve (shutter valve) is placed in the middle of the intake passage that communicates with the remaining intake ports.
During high-load operation, the blockage valve is opened to secure the passage area of the intake passage, thereby achieving high output. On the other hand, during low-load operation, the blockage valve is closed to narrow the passage area of the intake passage and reduce the intake flow rate. This was done to increase the intake air swirl in the combustion chamber, thereby improving combustibility.

However, in this conventional intake system, the closure valve is controlled to open and close depending on the operating condition to increase output at high loads and improve combustibility at low loads, so the valve mechanism is complicated. However, there was a problem in that it also required a complicated control system.

[Purpose of the invention]

In view of these problems, the present invention provides an intake system for a multi-valve engine that can increase output at high loads and improve combustibility at low loads without using a complicated valve mechanism or control system. That is.

[Structure of the invention]

The inventor of the present invention conducted extensive research to develop a device that could achieve output amplification during high loads and improvement of combustibility during low loads without using a valve mechanism, and as a result, the shape of the intake passage, etc. was well set. However, I discovered that it would be better to apply intake dynamic pressure to the swirl port.

In other words, in this type of intake system, from the perspective of achieving high output under high loads, emphasis is placed on securing the passage area of the intake passage, and the intake system is designed to ensure that the intake passage has a sufficient passage area, and that intake air is supplied to all intake ports or to intake ports other than the swirl port. The shape of the intake passage is designed to apply dynamic pressure, and as a result, as mentioned above, when the load is low, it is necessary to throttle the intake passage with a closure valve and guide the intake air flow to the swirl port.

On the other hand, if the shape of the intake passage is set so that intake dynamic pressure is applied to the swirl port, most of the intake air will flow to the swirl port at low loads with a small amount of intake air.
As a result, an intake swirl can be generated without providing a separate valve mechanism, and combustibility can be improved. However, in this case, the question arises as to whether passage resistance increases when the intake air volume increases under high load and the filling efficiency decreases.However, as the intake air volume increases, the intake air volume and swirl port increase. Due to the relationship with the passage resistance, the intake air flows not only through the swirl port 1, but also through the remaining intake ports, thereby securing the passage area of the intake passage and ensuring high engine output.

Accordingly, the present invention provides an intake system for a multi-valve engine in which at least one of the plurality of intake ports is formed as a swirl port, and the swirl port is arranged substantially on an extension of the center axis of the intake passage. is branched on the downstream side to communicate with a plurality of intake ports, and the intake passage is curved so that its center of curvature is located on the opposite side of the remaining intake ports when viewed from the swirl port, thereby improving intake movement. It is designed to apply pressure to the swirl port.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 and 2 show an intake system for a multi-valve engine according to an embodiment of the present invention. In the figure, 1 is a four-cylinder engine, and the cylinder head 2 of the engine 1 has first to fourth cylinders.
A first opening into each combustion chamber 3 of the cylinder. Second intake port 4
a, 4b and an exhaust port 5 are formed, and the intake and exhaust ports 4. a, 4b.

5 is provided with an intake valve 6 and an exhaust valve for opening and closing the opening. Spark plugs 7 are respectively attached to the cylinder head 8 so as to face each combustion chamber 3.

Further, a flange portion 8a at the downstream end of the intake manifold 8 is fixed to the side wall of the cylinder head 2. This intake manifold 8 constitutes an intake passage 9, and the intake passage 9 is branched into two by a partition wall 9a on the downstream side thereof. It communicates with second intake ports 4a and 4b. Each of the intake manifolds 8 is curved upward on the upstream side to form an abbreviated shape on the side, and the upstream end thereof is connected to the bottom wall of the surge tank 10, and the upstream end of the surge tank 10 is connected to a throttle valve. A throttle chamber 12 having a built-in throttle valve 11 is connected thereto.

On the other hand, near the downstream end of the intake manifold 8, a fuel injection valve 13 is provided offset from the central axis a of the intake passage 9 toward the first intake port 4a. The spray angle (see arrow A in FIG. 2) is set in such a direction as to point toward the lower tip of the partition wall 9a, and the spray angle (see arrow B in FIG. 1.2) is such that the injected fuel is in the first direction. 2nd intake port) 4a.

The angle is set so that the light is almost evenly distributed to the 4b. The upper part of the fuel injection valve 13 is inserted into a fuel delivery pipe 14, and the delivery pipe 14 is tightened and fixed to a stay 15 formed in the intake manifold 8 with a bolt 16, so that the manure fuel injection valve 13 is inserted into the intake manifold 8. It is pressed and fixed to the manifold 8.

In this device, the first intake port 4a is formed as a swirl port that is opened in the tangential direction of the cylinder and guides the intake air in the tangential direction, and is approximately parallel to the central axis a of the intake passage 9. placed on an extension line. The intake manifold 8 is curved so that its center of curvature is located on the opposite side of the second intake port 4b when viewed from the first intake port 4a.

Next, the operation will be explained.

When the engine operates, an amount of intake air corresponding to the throttle opening is introduced into the surge tank 10 by the action of the engine's intake negative pressure, and the intake air is transferred from the surge tank 10 into the intake manifold 8 of the cylinder on the intake stroke. The fuel is mixed with the sprayed fuel from the fuel injection valve 13 in the intake manifold 8, and is supplied into the combustion chamber 3.

When the engine is under low load, the amount of intake air is small, so the intake air is influenced by the shape of the intake manifold 8, and most of it flows from the first intake port 1-48, which is the swirl port, into the combustion chamber. 3 (supplied to the troops, this creates an intake swirl in the combustion chamber 3, resulting in good combustion. By the way, as mentioned above, most of the intake air is in the first intake port) 4a When it flows to
Since the injection direction A of the fuel injection valve I3 is set to the lower part of the tip of the partition wall 9a, there is a question that some of the injected fuel may be supplied to the second intake port 4b side and not be mixed well with the intake air. occurs. However, in this case, the injection direction A of the fuel injection valve 13 moves toward the first intake port 4a − side under the influence of the intake air flow, so that the injected fuel is well mixed with the intake air.

On the other hand, when the engine is in a high load state and the intake air amount increases, the intake air is divided between the intake air amount and the first intake port 4a.
Due to the passage resistance of This can be increased to ensure high engine output.

In addition, at that time, as described above, the injection direction A of the fuel injection valve 13 is
is set at the bottom of the tip of the partition wall 9a, so the injected fuel is injected into the first. Second intake port 4a.

4b, and a portion of the injected fuel adheres to the inner wall of the port and is drawn into the intake air flow, resulting in good atomization.

The device of this embodiment as described above is configured to apply intake dynamic pressure to the first intake port, which is a swirl port, so that an intake swirl can be generated without providing a complicated valve mechanism or control system. This improves combustibility at low loads. Furthermore, when the engine is under high load, the intake air also flows to the second intake port due to the relationship between the intake air amount and the passage resistance of the swirl port, thereby ensuring the passage area of the intake passage and ensuring high output.

In addition, although the case in which two intake ports are provided has been described in the embodiment described in "-," there may be two or more intake ports.

〔Effect of the invention〕

As described above, according to the intake system for a multi-valve engine according to the present invention, at least one of the plurality of intake ports is formed as a swirl port, and the swirl port is formed at approximately the extension line of the center axis of the intake passage. The intake passage is arranged so that the intake passage is branched on the downstream side to communicate with a plurality of intake ports, and the center of curvature of the intake passage is located on the opposite side of the remaining intake ports when viewed from the swirl port. Since it is curved, it is possible to improve combustibility at low loads and increase output at high loads without providing a complicated valve mechanism or control system.

[Brief explanation of drawings]

■It is a line sectional view.

Claims (1)

[Claims] (1) In an intake system for a multi-valve engine in which a plurality of intake ports are opened to one combustion chamber and an intake valve is arranged in each intake port, at least one of the plurality of intake ports is opened. , a swirl port is formed that opens in the tangential direction of the cylinder and guides intake air in the tangential direction, and the swirl port is located approximately on an extension of the central axis of the intake passage that supplies intake air to the plurality of intake ports. , the intake passage is branched on the downstream side to communicate with each of the intake ports, and the center of curvature of the intake passage is located on the opposite side of the remaining intake ports when viewed from the swirl port. 1. An intake device for a multi-valve engine, characterized in that the intake device is curved to apply intake dynamic pressure to the swirl port.