JPH0725234U - Internal combustion engine intake system - Google Patents

Abstract

(57) [Summary] [Purpose] While reducing the variation in swirl intensity generated in each cylinder to reduce the amount of smoke produced, it is possible to improve the output at a low cost without changing the shape of the intake port at all. To provide an intake system for an internal combustion engine capable of improving fuel efficiency. [Structure] At least one of a plurality of intake ports 4 formed in a cylinder head 3 of an internal combustion engine approximates the strength of a swirl generated in each intake port 4 to the strength of a swirl generated in another intake port 4. An intake device for an internal combustion engine, which is provided with a tubular port liner 5.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an intake system for an internal combustion engine in which variations in the intensity of swirl generated in an intake port for each cylinder are eliminated.

[0002]

[Prior art]

 As shown in FIG. 4, the intake system of the internal combustion engine sucks the air filtered by an air cleaner (not shown) into the inlet cover 2 through the intake duct 1, and at the inlet cover 2, the cylinder head 3 receives the air. It is designed to be distributed to the intake port 4 for each formed cylinder.

For the convenience of production, the shape of each intake port 4 is the same, and the connection position of the intake duct 1 communicating with the inlet cover 2 is normally the center of the inlet cover 2. Since it is a part, the flow path of the air flowing into each intake port 4 is different, and the strength of the swirl that is generated also varies considerably.

[0004]

[Problems to be solved by the device]

 In this way, if there are variations in the flow path of the air flowing into each intake port, an appropriate swirl will be generated in the air flowing into some cylinders, but it will be appropriate for the air flowing into the other cylinders. There was a problem that the swirl weaker than the above range or the strong swirl would occur, and the combustion condition would deteriorate. Further, due to this, there are problems that the amount of smoke produced exceeds the exhaust gas regulation value, and there are inconveniences such as reduction of output and deterioration of fuel efficiency.

In view of the above problems, the present invention reduces variations in swirl strength that occur in each cylinder, reduces the amount of smoke produced, and does not change the shape of the intake port at all, resulting in low cost. However, it is an object of the present invention to provide an intake system for an internal combustion engine that can improve output and fuel efficiency.

[0006]

[Means for Solving the Problems]

 The intake device for an internal combustion engine according to the present invention for achieving the above object has at least one of a plurality of intake ports formed in a cylinder head of the internal combustion engine, the strength of a swirl generated in the intake port. Is provided with a tubular port liner that approximates the strength of the swirl generated in other intake ports.

The strength of the swirl generated in each intake port changes depending on various conditions such as the shape of the intake port formed in the cylinder head and the connection position of the intake duct connected to the inlet cover. When installing, it is not necessary to install it on the intake port that falls within the proper swirl strength range, but the port liner should be installed on the intake port so that a moderate swirl can be generated for cylinders outside the proper range. It is preferable to attach it by means such as spot welding.

[0008]

[Work]

 The intake system for an internal combustion engine according to the present invention has the above-described structure. Even if the intake ports have the same shape in all cylinders, the port liner is provided in a specific intake port to provide a port It is possible to generate a swirl that is close to the swirl strength that occurs in the intake port of a cylinder without a liner, and it is possible to generate a substantially uniform swirl in all cylinders.

[0009]

【Example】

 An embodiment in which the intake system for an internal combustion engine of the present invention is applied to the conventional example shown in FIG. 4 will be described with reference to the drawings. First, in the conventional example of FIG. 4, the position of the intake duct 1 connected to the inlet cover 2 is between the 2nd port 4b and the 3rd port 4c of the four intake ports 4, and the 1st port 4a And the swirl generated in the 2nd port 4b and the swirl generated in the 3rd port 4c and the 4th port 4d, the directions of the inflow of the intake air into the intake port 4 are opposite directions. You can make a difference.

That is, the swirls of the first port 4a and the second port 4b are relatively strong, and the swirls of the third port 4c and the fourth port 4d are relatively weak. Therefore, in the first embodiment, as the low swirl setting, as shown in FIG. 1, the ports 1a and 4b are arranged to match the strength of the swirl generated in the ports 3c and 4d. Insert the square tubular port liner 5 as shown in Fig. 2 and spot weld the flange 5a to the cylinder head 3 to generate swirls at the 1st port 4a and 2nd port 4b. And rectified to approximate the swirl generated at port 4d.

The port liner 5 is formed in a tapered shape so that the opening area on the upstream side is larger than the opening area on the downstream side. Adjustment of the taper angle and the end position on the downstream side are formed. The swirl strength is adjusted by the extent to which is extended from the position of the flange portion 5a on the upstream side. In the first embodiment, the downstream end position of the port liner 5 extends from the inlet of the intake port 4 to the vicinity of the center, and the inertia of the air flowing from the inlet cover 2 into the intake port 4 is increased. Is attenuated and rectified so as to follow the shape of the inner wall of the port liner 5.

If the port liner 5 has a short length and is provided only near the inlet of the intake port 4, the effect of attenuating the inertia of the air flowing into the intake port 4 described above is not sufficient, so It is necessary to extend to the center of Port 4. Next, in the second embodiment, as the high swirl setting, as shown in FIG. 3, the third swirl port 4c and the fourth swirl port 4d are set to match the strength of the swirl generated in the first port 4a and the second port 4b. A port liner 5 with a taper angle different from that of No. 1 is attached.

Also in the case of the second embodiment, as in the case of the first embodiment, the swirl strength is set to be substantially uniform in each intake port 4, so that the swirl strength is increased in all cylinders. It comes to fall within the range of appropriate values. Also, since the swirl strength is moderate, not only can the combustion state be improved and the amount of smoke produced can be reduced, but the output and fuel consumption can also be improved.

[0014]

[Effect of device]

 The intake system for an internal combustion engine according to the present invention generates the swirl strength generated in at least one of the plurality of intake ports formed in the cylinder head of the internal combustion engine in the other intake ports. Since the tubular port liner that approximates the strength of the swirl is provided, the following effects can be achieved.

Even if the intake ports have the same shape in all cylinders, by providing the port liner at a specific intake port, a swirl close to the swirl strength generated in the intake port of the cylinder without the port liner can be provided. It is possible to generate a swirl that is almost uniform in all cylinders. Therefore, it is possible to reduce the variation in swirl intensity generated in each cylinder without changing the shape of the intake port at all, and as a result, it is possible to reduce the amount of smoke produced, improve the output and improve fuel efficiency. be able to.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an intake system for an internal combustion engine according to a first embodiment of the present invention.

2 (a) is a perspective view of a port liner used in the intake system for the internal combustion engine of FIG. 1, (b) is a front view thereof, and (c) is a side view thereof.

FIG. 3 is a schematic diagram of an intake system for an internal combustion engine according to a second embodiment of the present invention.

FIG. 4 is a schematic diagram of a conventional intake device for an internal combustion engine.

[Explanation of symbols]

 3 Cylinder head 4 Intake port 5 Port liner

Claims (1)

[Scope of utility model registration request] 1. A tubular structure in which at least one of a plurality of intake ports formed in a cylinder head of an internal combustion engine has a strength of a swirl generated in this intake port approximate to a strength of a swirl generated in another intake port. An intake system for an internal combustion engine equipped with a port liner.