JPS5843653Y2 - Intake system for multi-cylinder internal combustion engine - Google Patents

Description

[Detailed description of the invention] This invention is an intake system that makes combustion in each cylinder approximately equal when supplying air-fuel mixture from a carburetor to each cylinder via an intake branch pipe in a multi-cylinder internal combustion engine. It is related to.

Generally, the supply of air-fuel mixture to each cylinder in a multi-cylinder internal combustion engine is carried out through an intake branch pipe that branches from the intake pipe's gathering part where the carburetor is attached. Due to the opening/closing direction of the throttle valve or the opening position of the bi-nozzle, uneven flow occurs in the air-fuel mixture, resulting in a rich or lean air-fuel mixture for each cylinder.As a result, the combustion of the air-fuel mixture for each cylinder is not evened out. As a result, the output of each cylinder becomes unbalanced, and the cylinders that intake a rich mixture may misfire.
This not only causes smoldering, but also causes problems such as increased generation of harmful gases such as HC and Co.

In this way, the intake air mixture to a multi-cylinder internal combustion engine is made rich and lean for each cylinder, and the invention supplies air, blow-by gas, or exhaust gas to the cylinders in which the rich mixture is produced. This problem has been solved, and this example will be explained with reference to the drawings of an example in which this example is applied to a four-cylinder internal combustion engine. In the drawings, 1 indicates the first cylinder C1.
, shows a four-cylinder internal combustion engine consisting of a second cylinder C2, a third cylinder C3, and a fourth cylinder C4, and the ignition is performed in the order of the first cylinder C1 - the third cylinder C3 - the fourth cylinder C4 - the second cylinder C2, Also the first
Cylinder C1 - 2nd cylinder C2 - 4th cylinder C4 - 3rd cylinder C3
It is supposed to be done in this order.

Reference numeral 2 denotes an intake pipe for distributing and introducing the air-fuel mixture from the carburetor 10 into each cylinder C1, C2+C3tC4 of the internal combustion engine 1, and the intake pipe 2 is connected to the collecting part 3 to which the carburetor 10 is attached.
It is divided into two branch pipes, which are further divided into branch pipes 5, 5.5.
, 5, and the branch pipes 5, 5, 5.5 are connected to the intake ports 4.4, 4.4 of each cylinder.

Then, the ignition order (intake order) of adjacent cylinders or the subsequent cylinders of consecutive cylinders, for example, C1c3-C4-C2.
When igniting in this order, the first cylinder C1 and the fourth cylinder C4,
In addition, when igniting in the order of Cl-C2-C4C5, a control device such as a check valve is installed in the supply hole 6 opened in the middle of each branch pipe 5.5 of the intake manifold in the second cylinder C2 and the third cylinder EC3. The structure is such that an appropriate amount of a portion of at least one type of gas among air, blow-by gas, and exhaust gas is supplied via γ.

In other embodiments, this air, blow-by gas, or exhaust gas is supplied from a supply hole 6' (indicated by a two-dot chain line in FIG. 2) that opens into the intake port 4 of the cylinder head of the air joint in the embodiment described above. This may be done via a control device γ' such as a check valve, and in the third embodiment, as shown in FIG. is provided, and air is supplied via a control device f such as a check valve.
At least one kind of mixture dilution gas of blow-by gas and exhaust gas is supplied.

Control device 7.7',? ” is used to supply or not supply gas, or to control the amount of gas supplied, depending on the temperature and operating conditions of the engine.

In the intake system configured as described above, when the ignition order of the engine 1 is Cl-C3-C4-C2, the third cylinder C3
During intake into the fourth cylinder C4 following the second cylinder C4, or the first cylinder C1 following the second cylinder C2, the air-fuel mixture from the gathering part of the intake pipe to the inside of the branch pipe and the liquid fuel adhering to the inner wall of the pipe, or the liquid fuel before that. With the flow inertia given towards the third cylinder or the second cylinder, the fourth cylinder C4 or the first air fdc
Since air is taken into the fourth cylinder C4 and the first cylinder, the air mixture becomes rich, and the ignition order is Cl-C.
For the engine in the order 2-C4-C'3, the intake air mixture to the second cylinder FC2 and the third cylinder becomes richer for the same reason.

According to the present invention, air is transferred from the intake branch pipe 5 of the cylinder where the air-fuel mixture is richer than that of other cylinders to an appropriate location at the intake valve 8 opening 1 of the intake port 4 in the cylinder head of that cylinder. By supplying an appropriate amount of at least one type of gas, such as gas or exhaust gas, the mixture in the cylinder is diluted, and as a result, the amount of fuel entering the combustion chamber in each cylinder becomes approximately equal, and the combustion state is improved. Because it can be roughly averaged, the output to each cylinder is not imbalanced, and the engine operating noise can therefore be reduced.Furthermore, misfires and smoldering in specific cylinders are eliminated, which reduces the generation of harmful gases such as HClCO. Has a low frequency effect.

Although the above embodiment has been described for the case where the intake air mixture in each cylinder is rich and thin due to the arrangement and shape of the intake pipe, the present invention is not limited to this. Even if the intake air mixture for each cylinder can be rich or lean due to various other reasons such as the opening/closing direction of the throttle valve or the opening direction of the main nozzle, at least the amount of air, blow-by gas, and exhaust gas for the cylinder in which the rich mixture enters By supplying one or more types of mixture dilution gas, it is possible to apply the same method, and especially when supplying exhaust gas, the inertness of the gas can be used to reduce the combustion temperature in the cylinder and generate ONX. The exhaust gas released into the atmosphere is purified, making it effective in preventing pollution.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a plan view of an internal combustion engine, FIG. 2 is an enlarged cross-sectional view of the main parts with some parts omitted, and FIG. 3 is an enlarged and partially omitted main part of the third embodiment. FIG. 1... 4-cylinder internal combustion engine, 2... Intake pipe, 5... Branch pipe, 4... Intake port, 8... Intake valve, 6, 6'
... Supply hole, 9... Supply pipe, I/TI, f... Control device, CI + C2tC31C4... Cylinder.

Claims (1)

[Scope of utility model registration request] In a multi-cylinder internal combustion engine, the branch pipe of the intake pipe where the carburetor is installed upstream is connected to each cylinder, and the intake air is transferred to the cylinder head of that cylinder from the branch pipe connected to the cylinder with a richer mixture than other cylinders. An intake system for a multi-cylinder internal combustion engine configured to supply an appropriate amount of at least one type of gas among atmospheric air, blow-by gas, and exhaust gas to any location in a valve opening 1.