JPS63280822A - Intake device for multi-cylinder engine - Google Patents

Abstract

PURPOSE:To enable close arrangement of an air box or an intake pipe to an engine body by providing two air boxes elongated in the direction of a row of cylinders closely to an engine body at the upper side thereof, and arranging intake pipes in a space surrounded by the air boxes. CONSTITUTION:When the invention is applied on a series four cylinder engine, a first air box 17 is arranged at a discharge path side above a cylinder head 3 while a second air box 18 is arranged at an intake path side. The air boxes 17, 18 are elongated in the arranging direction of cylinders, where the first air box 17 is opened through collected pipes 17a to the atmosphere with one end thereof communicated through a communication pipe 19 with the second air box 18. A suction pipe 21 coupled with an intake path 12 traverses above the cylinder head 3 and coupled with the first air box 17, while furthermore branched in the way to provide a high speed path 22 which is coupled with the second air path 18. High speed valves 23b, 23a closable under low speed load are arranged in the way of the high speed path 22 and in the upstream of the communication path 19.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to improvements in a high-performance multi-cylinder engine mainly suitable for use in passenger cars. It is related to.

[Conventional technology]

In recent years, multi-cylinder engines for automobiles have sought to improve high-speed performance, but in order to avoid sacrificing low-speed performance even in high-speed engines, they have been equipped with relatively long and large intake passages. The engine is also large and requires various measures to be accommodated in the narrow engine compartment. In other words, the intake passage connected to one side of the engine is bent upward, crosses the upper part of the cylinder head, and opens into an air box provided on the other side (for example, in Japanese Patent Laid-Open No. 5
8-10130). Recently, consideration has been given to further shortening the intake passage for high-speed vehicles.

[Problem that the invention seeks to solve]

As a result, it is necessary to provide separate air boxes for the normal use passage and the high speed passage, which tends to cause large irregularities in the external shape of the engine, resulting in the problem of increasing the external size of the engine.

[Means for solving problems]

This invention aims to obtain an intake structure in an engine equipped with two types of intake passages, one for regular use and one for high speed use, in which they are arranged rationally and the external size is prevented from increasing as much as possible. The purpose of this system is to open an exhaust passage on one side of an engine body in which multiple cylinders are arranged in a line and an intake passage on the other side. A first air box that communicates with the first air box and a second air box that communicates with the first air box via a communication pipe on the intake passage side are provided,
These are formed into a long and narrow box shape along the direction in which the cylinders are arranged, and the communication pipe is arranged in a part of both air boxes, while the intake pipe connected to the engine body is bent upward and the air intake pipe connected to the engine body is bent upward and crossed over the other side. A high-speed passage is provided, which opens into a first air box provided on the side, branches the intake pipe midway, and opens into the second air box, and at least one of the communication passage and the high-speed passage is connected to a low-speed engine operation. It is unique in that it has a high-speed valve that closes occasionally.

[Effect]

The air boxes can be arranged close to the engine body and do not protrude outwardly from there, and the intake pipes do not protrude outwardly from the outer surface of the air boxes either.

〔Example〕

The present invention will be explained below with reference to the illustrated embodiment. FIG. 1 is a cross-sectional view of an engine. is configured. 6 is a crankshaft, and 7 is a connecting rod that connects the piston 4 and the crankshaft 6. In this embodiment, the engine 1 is of an in-line four-cylinder type, and four cylinders and two cylinders are arranged in parallel in the axial direction to form an engine body. The engine 1 is mounted in an engine chamber 8 formed on the front side of the automobile, with the crankshaft 6 facing in the direction of travel.

9 is an engine hood that forms the earthen wall of the engine room 8.

The combustion chamber 5 is connected to an intake passage 12 via an intake valve 11 and an exhaust passage 14 via an exhaust valve 13. It is opened and closed by the camshaft 15 and the exhaust camshaft 1B. 6m is a timing belt wound between the crankshaft 6 and both camshafts 15 and 18. Note that the above configuration is not much different from a conventional engine.

In this invention, the intake passage 12 is configured as follows. That is, the first air box 1 is located on the upper side of the cylinder head 3 forming the engine body, and is located on the exhaust passage side.
7 and a second air box 18 are provided on the intake passage side.

These air boxes 17 and 18 are die-cast aluminum and have an elongated box shape along the direction in which the cylinders are arranged, and their height varies depending on the inclination of the engine hood 9, as shown in FIG. It is a change. 1st air box 1
7 is open to the atmosphere via a collecting pipe 17Jl, and one end communicates with the second air box 18 via a communicating pipe 19.

17b is a manually operated throttle valve. On the contrary,
Intake pipe 2 connected to intake passage 12 of cylinder head 3
1 is immediately bent upward and opens into a first air box 17 provided across the top of the cylinder head 3 on the other side. The intake pipe 21 branches in the middle to form a second air box 18.
A high speed passageway 22 is provided which opens into the interior. Thus,
In addition to an intake pipe 21 which is made relatively long and operates over the entire operating speed range, and which is particularly tuned to medium and low speed operating ranges, a high-speed passage 22 which is tuned to high-speed operation is formed. 23m, 23k)
Both are high-speed valves, which are installed on the upstream side of the communication pipe 19 and in the middle of the high-speed passage 22, and are controlled to close at least in the low speed and low load range of the engine. In other words, as shown in Figure 4, both valves are closed at low speed and low load.
In the high-speed, high-load region C, both valves are open, and in the remaining region B, only the high-speed valve 23a provided on the upstream side of the communication pipe 19 is open. In the low-speed, low-load region A below the torque K, only the intake pipe 21 set for low speed is connected to the combustion chamber 5, and the desired low-speed performance is satisfied. Engine speed or load (
When the opening degree of the throttle valve 17b increases more than expected, only the high-speed valve 23a opens, the communication pipe 19 is connected to the first air box 17, and its tip is closed by the other high-speed valve 23b. Therefore, this functions as a side branch of the first air box 17, destroys the low speed side resonance characteristics of the intake pipe 21, and improves the output characteristics in the medium speed and medium load range. Further, in the high-speed, high-load region C, both valves 23a and 23b are opened to increase the maximum value of the intake air amount.

Next, the operation of this engine will be explained. First, when the engine is started and operated at low speed, the high speed valve 23 is closed and the entire amount of intake air is supplied into the combustion chamber 5 through the conventional intake pipe 21 which is relatively thin and long. During this time, the intake pipe 21 is completely cut off from the high-speed passage 22, so it is possible to ignore the high-speed operating range when setting its resonance speed.
Design becomes easier.

When the engine is operated at high speed and high output, the high speed valve 23 is opened and intake air is supplied into the combustion chamber 5 through both the intake pipe 21 and the high speed passage 22. As a result, the engine can obtain high output torque over a wide speed range from a low speed operating range to a high speed operating range.

The first air box, the second air box, the communication pipes constituting the communication passage, and the intake passages of each cylinder have their upper surfaces substantially on the same plane. Since the air box is arranged and the intake pipe connected to them is configured to extend between the two air boxes or directly below the air box, the air box can be placed close to the engine body and does not protrude outward from there. Also, the intake pipes do not protrude significantly outward from the outer surface of these air boxes.

〔Effect of the invention〕

As described above, the present invention provides a first air box and a second air box close to the upper side of the engine main body, and forms them into an elongated box shape extending in the direction in which the cylinders are arranged. The intake pipe is placed in the enclosed space, and the air box and intake pipe are switched and operated by high-speed valves, so the air box and intake pipe can be placed close to the engine body, avoiding an increase in the external size of the engine. ＼Has the effect of enabling the engine to have excellent output characteristics.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a cross-sectional view of the engine, FIG. 2 is a cross-sectional view of the engine, and FIG.
-1 sectional view and FIG. 4 are operation diagrams showing the operation area of the high-speed valve. 12. Intake passage, 1711... 1st air box, 1
8...Second air box, 19...Communication pipe, 21...
・・Intake pipe, 22・・e・High speed passage, 23a, 23b・
...High speed valve. Patent applicant Yamaha Motor Co., Ltd. Agent Masaki Yamakawa ((12 people)) Figure 1 Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) An engine body in which multiple cylinders are arranged in a line has an exhaust passage on one side and an intake passage on the other side, and a An air box and a second air box that communicates with the first air box through a communication pipe are provided on the intake passage side, and these are formed into an elongated box shape along the direction in which the cylinders are arranged, and the communication pipe is connected to both air boxes. On the other hand, the intake pipe connected to the engine body is bent upward, crosses above it and opens into the first air box provided on the other side, and the intake pipe is branched in the middle to form the first air box. 2. An intake system for a multi-cylinder engine, comprising a high-speed passage opening into two air boxes, and a high-speed valve that is closed during low-speed operation of the engine provided in at least one of the communication passage and the high-speed passage. (2) The multi-cylinder engine according to claim 1, wherein the first air box, the second air box, the communication pipe constituting the communication passage, and the intake passage of each cylinder have upper surfaces substantially on the same plane. intake device.