JPH08338253A - Intake system for engine - Google Patents

Abstract

PURPOSE: To provide an intake chamber having a sufficient capacity and surely functioning in an intake route without effort, save the time for assembling, cancel the action of the intake chamber under the operating condition where no intake chamber is needed, and realize satisfactory output characteristic and engine response under all operating conditions. CONSTITUTION: An intake system A for engine has an intake chamber 32 for storing air-fuel mixture and a connecting passage 35 for allowing the intake chamber 32 to communicate with the intake passage 21 of air-fuel mixture supplying means (carburetor 18), which are integrated to the air-fuel mixture supplying means 18 for supplying the air-fuel mixture to an engine 1. It also has valve means (rotary valve 36) for opening and closing the connecting passage 35; driving means 37 for opening and closing the valve means; and control means 41 for controlling the valve means to close under the engine operating state where the intake chamber 32 is not needed through the operation of the driving means 37.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine intake system in which an intake chamber is connected in the middle of an intake path connected to an intake port of an engine to reduce pressure fluctuations of an air-fuel mixture in the intake path to improve intake efficiency. It relates to the device.

[0002]

2. Description of the Related Art FIG. 3 is a vertical cross-sectional view showing an example of a vehicle engine and its intake device. The intake port 101 of the engine 100 is connected to the carburetor via the inlet pipe 102.
103 Alternatively, a mixture supply means such as a fuel injection device is connected.

During the intake stroke of the engine 100, the intake valve 104 is opened, the piston 106 is lowered in the cylinder bore 105, and the inside of the cylinder bore 105 becomes a negative pressure, so that the air-fuel mixture generated by the carburetor 103 is introduced into the intake port 10.
Intake from 1 to the cylinder bore 105.

By the way, the pressure of the air-fuel mixture in the intake port 101 constantly changes as the intake valve 104 opens and closes. This is due to the flow inertia of the air-fuel mixture, and becomes remarkable especially when the throttle opening of the carburetor 103 is small. Such pressure fluctuations of the air-fuel mixture may significantly reduce the intake efficiency, reduce the output of the engine 100, and cause a poor response when the throttle of the carburetor 103 is suddenly opened.

Therefore, a tank-shaped intake chamber 108 is connected to the inlet pipe 102 via a connecting hose 107, for example, in the middle of the intake path.
By reducing the pressure fluctuation of the air-fuel mixture in 108, the intake efficiency and the engine response are improved (for example, JP-A-56-129717 and JP-A-61-61912).

[0006]

However, in recent vehicle engines, the inlet pipe 102 is shortened to reduce the engine 100 and the carburetor 103 in order to make the engine compact and improve the performance in the high-speed rotation range (improvement of engine response, etc.). Many models are in close proximity. For this reason, there is almost no connection place for the connecting hose 107, and the layout of the intake chamber 108 is also poor due to the large number of auxiliary machines and the like being provided around the engine 100. Further, it is difficult to secure the required chamber capacity, and it is not possible to achieve sufficient performance improvement.

Furthermore, since it is necessary to fix the intake chamber 108 to the vehicle body and then connect it to the inlet pipe 102 with the connecting hose 107, it takes a lot of time and labor to assemble them, and the connecting hose 107 has a large number of parts. Air leakage easily occurs at the connecting portions at both ends, and if air leakage occurs here, engine performance will be significantly impaired. The above problems become more serious as the number of cylinders in the engine increases.

The present invention has been made in order to solve such a problem, and an intake chamber having a sufficient capacity and surely functioning can be provided in the vicinity of the intake path without difficulty, and the assembling is troublesome. An object of the present invention is to provide an intake device for an engine that does not overhang.

Another object of the present invention is to cancel the action of the intake chamber under operating conditions in which the intake chamber is unnecessary, and to provide good output characteristics and engine response under all operating conditions.

[0010]

In order to achieve the above object, the intake system for an engine according to the present invention has an air-fuel mixture supply means for supplying air-fuel mixture to an engine as described in claim 1. Is integrally provided with a connection passage for communicating the intake chamber with the intake passage of the air-fuel mixture supply means.

Further, in the intake system for an engine according to the present invention, as described in claim 2, valve means for opening and closing the connecting passage, driving means for opening and closing the valve means, and the driving means are operated. And a control means for controlling the valve means to close under engine operating conditions where the intake chamber is unnecessary.

[0012]

If the intake device of the engine is constructed as in claim 1, since the intake chamber and the connecting passage are provided in the air-fuel mixture supply means itself, the intake chamber having a sufficient capacity can be provided in the vicinity of the intake passage without difficulty. be able to. Since the intake chamber and the connection passage are integrally molded inside the air-fuel mixture supply means and do not have a hose connection portion or the like outside, there is no fear of air leakage. In addition, since the mixture supply means is attached to the engine and the intake chamber is attached at the same time, the assembling work is easy.

Further, when the intake device of the engine is constructed as in claim 2, the control means operates the drive means to close the valve means to close the connecting passage under the engine operating condition where the intake chamber is not required. Therefore, the action of the intake chamber is canceled, and good output characteristics are provided under all operating conditions.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an example in which the intake device according to the present invention is applied to an in-line multi-cylinder engine for a motorcycle.

In this engine 1, a cylinder block 3, a cylinder head 4, and a head cover 5 are fixed in order on a crankcase 2, and the cylinder block 3
A cylinder bore 6 is formed inside the cylinder bore 6
Is formed in the cylinder head 4.

A piston 8 slidably inserted in the cylinder bore 6 and a crankshaft 9 rotatably supported in the crankcase 2 are connected by a connecting rod 11, and the reciprocating motion of the piston 8 is crankshaft. It is converted into the rotational movement of 9 and becomes the output of the engine 1.

An intake port 12 and an exhaust port 13 connected to the combustion chamber 7 are formed in the cylinder head 4 so as to face each other. The intake port 12 is opened and closed by an intake valve 14, and the exhaust port 13 is opened by an exhaust valve 15. It is opened and closed. An exhaust pipe 16 is connected to the outside of the exhaust port 13.

The intake port 12 has an intake device A according to the present invention.
Is provided. This intake device A is provided with a carburetor 18 as a mixture supply means connected to an intake port 12 via an inlet pipe 17 made of synthetic resin or the like, and a drive means 37 and a control means 41 described later. ing.

During the intake stroke of the engine 1, the intake valve
When 14 opens, the piston 8 descends in the cylinder bore 6, and the air-fuel mixture generated by the carburetor 18 is sucked into the cylinder bore 6 from the intake port 12.

FIG. 2 is an enlarged vertical sectional view of the carburetor 18. The carburetor 18 has a laterally extending intake passage.
21 is formed, the valve mechanism chamber 22 is provided on the upper side of the intake passage 21 and the float chamber for storing the fuel on the lower side.
23 are provided. Further, a substantially cylindrical throttle valve 25 is slidably inserted in a throttle passage 24 formed so as to intersect with the intake passage 21, and the throttle valve 25 is provided in a valve mechanism chamber 22 to rotate. A link 27 is connected to the free end of the lever 26.

The turning lever 26 turns up and down about the support shaft 28, and the turning amount is proportional to the throttle operating amount of the motorcycle. By the vertical turning of the turning lever 26, the throttle valve 25 moves up and down in the throttle passage 24, and the passage area of the intake passage 21 changes.

From the lower part of the throttle valve 25, a needle valve 30 that narrows toward the tip extends, while a tubular jet nozzle 31 is provided vertically in the float chamber 23, and as the throttle valve 25 moves up and down. Needle valve
30 goes in and out of the jet nozzle 31. Jet nozzle
From 31, the fuel stored in the float chamber 23 is sucked in the form of mist and mixed with the air flowing through the intake passage 21 to generate an air-fuel mixture.

The carburetor 18 thus constructed is integrally provided with a closed chamber-like intake chamber 32.
The intake chamber 32 is integrally formed with the cap 18a that closes the upper portion of the valve mechanism chamber 22, for example. In addition,
The cap 18a is fixed to the carburetor main body 18b using screws 33, and is kept airtight by a gasket 34.

A connecting passage 35 is formed integrally with the cap 18a and the carburetor body 18b. This connecting passage 35 is provided in parallel with the throttle passage 24,
The intake chamber 32 is connected to the inside of the intake passage 21 on the downstream side of the throttle valve 25.

Further, a rotary valve 36 is provided in a portion where the connecting passage 35 is connected to the intake passage 21. The rotary valve 36 is a valve means configured to open and close the connection passage 35 by rotating, for example, 90 °, and is shown in an open state in FIG. 1 and a closed state in FIG. There is.

Further, the rotary valve 36 has a driving means 37.
Is provided. This drive means 37 is, for example, a servo motor.
38 and pulley transmission mechanism 39, servo motor 38
Is transmitted to the rotary valve 36 via the pulley transmission mechanism 39, and the rotary valve 36 is opened and closed.

The movement of the servomotor 38 is controlled by the control means 41 using a small CPU or the like. This control means 41
Receives the input of information such as the rotation speed of the engine 1, the throttle opening of the carburetor 18, the throttle speed, etc., and determines the operating condition of the engine 1, and closes the rotary valve 36 under the operating condition in which the intake chamber 32 is unnecessary. The drive means 37 is controlled.

When the throttle valve 25 of the carburetor 18 rises and the passage area of the intake passage 21 expands during the operation of the engine 1, the amount of air flowing through the intake passage 21 increases and at the same time the needle valve 30 is pulled out from the jet nozzle 31. The opening area of the jet nozzle 31 increases, and the amount of fuel sucked from the float chamber 23 also increases. Therefore, a large amount of air-fuel mixture is supplied to the engine 1 and the output of the engine 1 increases.

For example, the throttle valve 25 of the carburetor 18
When the opening degree of is small and the rotation speed of the engine 1 is low, the pressure fluctuation of the air-fuel mixture in the intake passage (the intake port 12, the inlet pipe 17, the intake passage 21) becomes remarkable,
There is a concern that the intake efficiency will decrease and the output of the engine 1 will decrease. Under such an operating condition, the control means 41 controls the drive means 37 to open the rotary valve 36 so that the intake chamber 32 communicates with the intake passage 21.

As a result, when the pressure in the intake passage (12, 17, 21) increases, a part of the air-fuel mixture is pushed into the intake chamber 32, and the pressure in the intake passage (12, 17, 21) decreases. And intake air from the intake chamber 32 to the intake path (12,17,2
1) Released into. Therefore, the intake path (12,17,2
The pressure fluctuation of the air-fuel mixture in 1) is alleviated, the intake efficiency is improved and the output of the engine 1 is improved, and the poor response when the throttle valve 25 of the carburetor 18 is suddenly opened is avoided.

When the throttle opening of the carburetor 18 is large and the rotation speed of the engine 1 is high, the pressure fluctuation of the air-fuel mixture in the intake path (12, 17, 21) is small, so that the intake chamber 32 is If it communicates with the intake passage 21, it will rather reduce the intake efficiency. Under such an operating condition, the control means 41 controls the drive means 37 to close the rotary valve 36 and cancel the action of the intake chamber 32.

According to the intake device A thus constructed,
Since the intake chamber 32 and the connection passage 35 are provided in the carburetor 18 itself, the intake chamber 32 having a sufficient capacity can be reasonably provided near the intake path (12, 17, 21). Since the capacity of the intake chamber 32 and the length of the connecting passage 35 can be arbitrarily set without being influenced by the members around the carburetor 18, it is possible to set highly effective specifications.

The intake chamber 32 and the connecting passage 35 are also provided.
Since it is integrally molded in the carburetor 18 and does not have a hose connection part or the like outside, there is no concern about air leakage, and the intake chamber 32 can function reliably. Moreover, since the number of parts is not increased by providing the intake chamber 32, the attachment of the carburetor 18 to the engine and the installation of the intake chamber 32 are completed at the same time, so that the assembly is not troublesome. This is very advantageous especially in the case of multi-cylinder engines.

Further, according to the present invention, the control means 41 is provided under the engine operating condition where the intake chamber 32 is unnecessary.
Operates the drive means 37 to close the rotary valve 36 and cancel the action of the intake chamber 32, so that good output characteristics and engine response can be obtained under all operating conditions.

In this embodiment, the carburetor 18 serving as the air-fuel mixture supply means uses the rotary lever 26 to rotate the throttle valve.
Although it is of a type that directly raises and lowers the 25, the present invention is not limited to this type, and may be a negative pressure responsive carburetor that senses a negative pressure in the intake passage and automatically moves the throttle valve up and down, for example. . Further, the present invention can be implemented not only by the carburetor but also by integrally providing the intake chamber 32 and the connection passage in the fuel injection device.

[0036]

As described above, in the engine intake system according to the present invention, the air-fuel mixture supply means for supplying the air-fuel mixture to the engine is provided with the intake chamber for storing the air-fuel mixture.
It is characterized in that the intake chamber is integrally provided with a connection passage that communicates with the intake passage of the air-fuel mixture supply means.

In this way, the intake chamber having a sufficient capacity can be provided in the vicinity of the intake path without difficulty, and there is no concern about air leakage, so that the intake chamber can function reliably. In addition, since the mixture supply means is attached to the engine and the intake chamber is attached at the same time, the assembling work is easy.

Further, the engine intake system according to the present invention is an engine in which the valve means for opening / closing the connecting passage, the driving means for opening / closing the valve means, and the intake chamber for operating the driving means are not required. Since the control means for controlling the valve means to be closed under operating conditions is provided, good output characteristics and engine response can be obtained under all operating conditions.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an engine and an intake device showing an embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional view of a carburetor.

FIG. 3 is a vertical cross-sectional view of an engine and an intake device showing a conventional technique.

[Explanation of symbols]

 A intake system 1 engine 12 intake port 17 inlet pipe 18 carburetor as a mixture supply means 21 intake passage 25 throttle valve 32 intake chamber 35 connecting passage 36 rotary valve as valve means 37 drive means 38 servo motor 39 pulley transmission mechanism 41 control means

Claims (2)

[Claims] 1. An intake chamber 32 for storing an air-fuel mixture in an air-fuel mixture supply means 18 for supplying an air-fuel mixture to an engine 1.
An intake device for an engine, characterized in that an intake passage (32) for communicating the intake chamber (32) with the intake passage (21) of the mixture supply means (18) is integrally provided. 2. Valve means 36 for opening and closing the connection passage 35,
A drive means 37 for opening and closing the valve means 36, and a control means 41 for operating the drive means 37 to control the valve means 36 to be closed under engine operating conditions where the intake chamber 32 is unnecessary. The intake system for the engine according to claim 1.