JPS61157717A - Air intake device of multicylinder engine - Google Patents

Abstract

PURPOSE:To facilitate incorporation of a fuel injection valve by dividing an air intake expansion chamber to which one end of each independent air intake passage whose the other end is connected to each cylinder is connected into upper and lower sides on a position lower than a central extending line of the fuel injection valve. CONSTITUTION:Each independent air intake passage 6 is opened to a combustion chamber 5 of each cylinder 4 through an intake port 7 formed in a cylinder head and forming a lower steam end unit. And each upper stream end is connected to an or intake expansion chamber 8 extending in parallel with engine longitudinal direction respectively. And an air intake system structure 12 for forming the chamber 8 and each passage 6 is divided into upper and lower portions on a position lower than acentral extension line l of the fuel injection valve 19 in a tank portion 13 on which the chamber 8 is formed, and composed of an upper side divided body 12a forming the tank portion 13 and respective upper half portions of respective integral air intake units 14 integrally, and a lower side divided body 12b forming the lower half portions of the units 14 and respective branched intake pipe units 15 and flanges 16 integrally.

Description

Detailed Description of the Invention (Field of Application in the Coal Industry) The present invention connects multiple cylinders and an intake expansion chamber through independent intake passages, thereby increasing the output by the dynamic effect of intake air (intake inertia effect). The present invention relates to an intake system for a multi-cylinder engine which is intended to improve the performance of the engine, and particularly to an improvement in the structure of the intake system.

(Prior Art) Conventionally, in an engine intake system, a negative pressure wave (pressure wave of negative pressure) generated with the start of intake is reflected at the open end of the intake passage to the atmosphere or the intake expansion chamber on the upstream side of the intake passage, and a positive pressure wave ( Taking advantage of the fact that the positive pressure wave becomes a positive pressure wave and is returned toward the intake boat, the positive pressure wave reaches the intake port just before the intake valve closes and forces the intake air into the combustion chamber. It is known to increase the filling efficiency of the intake air by the so-called inertia effect of the intake air. In order to obtain the intake inertia effect by matching the oscillation cycle of the pressure waves generated in the intake passage with the opening/closing cycle of the intake valve in a predetermined operating range using such technology, the intake passage must have a certain length. and
Further, the intake expansion chamber requires a certain volume.

On the other hand, when an engine and its intake system are mounted in the engine room of a passenger car, etc., the rear part is restricted by the front end of the passenger compartment, and the upper part is restricted by the bonnet, so it must be placed within a limited space. 1. There are space constraints.

For this reason, conventionally, as seen in U.S. Pat. No. 58-203338 and U.S. Pat. In an intake system for a multi-cylinder engine connected by an intake passage, in order to eliminate the above-mentioned space constraints and ensure the required intake passage length and intake expansion chamber capacity to obtain the intake inertia effect for each cylinder, It has been proposed that each of the independent intake passages is integrally formed around the intake expansion chamber using a part of the wall constituting the intake expansion chamber, thereby achieving compactness.

(The same ff1Ja that the invention seeks to solve> By the way, in the intake system as proposed above, when the fuel injection valve is installed in the independent intake passage, the fuel injection valve is in a state where the injected fuel is well atomized with good response. The fuel injection valve is mounted on the downstream side of the independent intake passage toward the combustion chamber opening of the intake boat so that the fuel is supplied to the combustion chamber of the intake boat. It is desirable that the downstream portion of the independent intake passage be formed into a substantially straight ring shape so that the intake air can be smoothly supplied to the combustion chamber.For these reasons and the demand for compactness, the center line of the fuel injector should be An intake expansion chamber may be located on the extension line.

However, in this case, when assembling the fuel injection valve into the independent intake passage, since the intake expansion chamber and each independent intake passage are integrally formed as described above, the intake expansion chamber on the central extension line may get in the way. The problem arises that the assembly becomes difficult.

Therefore, the present invention has been made in view of this point, and its purpose is to provide a dividing surface at an appropriate position for an intake expansion chamber in which each independent intake passage is integrally formed. Therefore, the objective is to ensure good assembly performance of the fuel injection valve while ensuring the required length of the intake passage and the required volume of the intake expansion chamber in the intake system within a limited space.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention is such that each independent intake passage that connects the intake expansion chamber and each cylinder independently of each other is arranged around the intake expansion chamber. A fuel injection valve is provided on the downstream side of the independent intake passage, and the center line of the fuel injection valve is extended. The present invention is directed to an intake system of a multi-cylinder engine in which the intake expansion chamber is located on a line, and the intake expansion chamber is divided into upper and lower parts at a position below the central extension line. This is what I did.

(Function) With the above configuration, in the present invention, each independent intake passage is integrally formed around the intake expansion chamber by using a part of the wall constituting the intake expansion chamber, so that it can be used within a limited space. While making it compact enough to fit in, the required length of the intake passage and the volume of the intake expansion chamber to reduce the intake inertia effect by 1q are secured, and the fuel injection valve is connected to the combustion chamber opening of the intake boat on the downstream side of the independent intake passage. It is possible to ensure good fuel response by installing the fuel in the direction of the fuel tank.

In addition, even if the intake expansion chamber is located on the extension line of the center line of the fuel injector due to the directional arrangement of the fuel injector, etc., the intake expansion chamber is located vertically at the position 1 below the center extension line. Since the lower divided part of the intake system is assembled into the engine, the fuel injection valve is installed on the downstream side of the independent intake passage, and then the upper divided part is connected to the lower divided part. By doing so, it becomes possible to easily assemble the fuel injection valve.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

1 to 3 show a first embodiment in which the present invention is applied to a four-cylinder, four-cycle engine. In the figure, reference numeral 1 denotes an engine body consisting of a cylinder block 2, a syringe head 3, etc., and the engine body 1 has four cylinders 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4. ... are formed in series.

A combustion chamber 5 is formed in each cylinder 4.

. Reference numeral 6 denotes independent intake passages provided independently of each other for each cylinder, and each independent intake passage 6 is connected through an intake port 7 formed in the cylinder head 3 and constituting the downstream end of the independent intake passage 6. It opens into the combustion chamber 5 of each cylinder 4, and the upstream ends of these independent intake passages 6, 6... each have a substantially rectangular cylinder-shaped intake expansion chamber 8 extending parallel to the longitudinal direction of the engine.
is connected to. An intake introduction pipe 9 for introducing outside air is connected to one end surface of the intake expansion chamber 8, and a throttle valve 10 for controlling the amount of intake air is disposed inside the intake introduction pipe 9.
is arranged, and the intake air introduced into the intake expansion chamber 8 through the intake introduction pipe 9 is supplied to the combustion chamber 5 of each cylinder 4 via each independent intake passage 6. Further, the intake port 7 is provided with an intake valve 11 .

12 is the intake expansion chamber 8 and each independent intake passage 6.6.
..., the structure 12 includes a tank part 13 forming the intake expansion chamber 8, and a side part from the upper part of the side opposite to the engine side of the tank part 13. The upstream portions 5a, 5 of each independent intake passage 6.6 extend by detouring around the tank portion 13 toward the side and lower side, and utilize part of its constituent walls, that is, the side wall and lower wall.
an integral intake pipe portion 14.14.
. . . and a downstream portion 6b of each independent intake passage 6, 6, which branches and extends from the lower side of each integrated intake pipe portion 14, 14, toward the engine side into individual air 11T4, 6
b... forming branch intake pipe portions 15,15...;
The multi-branch intake pipe parts 15, 15... each have 7 run 2 parts 16 that connect their tips to each other, and the flange part 16 connects the engine body 1 to the independent intake passage downstream of each branch intake pipe part 15. It is fixed to the engine body 1 by inserting and tightening bolts 17, 17, . . . from the side with the side portions 6b aligned with the intake ports 7 of each cylinder 4. Further, the upper side of the tank portion 13 on the engine side is formed so as to bulge toward the engine side, thereby ensuring a sufficient volume of the intake expansion chamber 8.

The independent intake passage F downstream portion 6b and each intake port 7 of each of the branched intake pipe portions 15 are formed to extend in a straight line toward the combustion chamber 5 from diagonally above and open into the combustion chamber 5. has been done. An injection valve mounting hole 18 is formed in the upper part near the downstream end of the independent intake passage downstream portion 6b of the multi-branched intake pipe section 15, and the fuel injection valve 19 has a seal ring 18a at its tip injection port. Through the above mounting hole 1
8 and is fixed. The installation direction of the mounting hole 18 and the fuel injection valve 19 is such that the fuel from the injection valve 19 is injected toward the intake valve 11 of the combustion chamber 5, and each fuel injection valve 19, 19... * is connected to a fuel supply pipe 20 arranged parallel to the longitudinal direction of the engine. As a result, the fuel injection valve 19 is installed in a lying state almost along the branch intake pipe section 15, and the intake expansion chamber 8 (tank section 13) is located close to the fuel injection valve 19 and the fuel supply pipe 20.

Furthermore, the intake expansion chamber 8 (tank portion 13) is connected to the fuel injection valve 1.
9, the intake system structure 12 is formed by being divided into upper and lower parts at a position below the center extension line 13 in the tank part 13. 13 and each integral plate trachea section 14.
14... Lower divided body 12a whose upper half is integrally molded
and the lower half of the tank part 13, the integrated plate trachea part 14.14.
. . , each branch intake pipe portion 15, 15 . a and 12b are joined via a sealing material 21 such as a gasket, and are hermetically coupled by inserting and tightening bolts 22, 22, etc. from below.

Therefore, in the above embodiment, the negative pressure wave generated in each cylinder 4 during the intake stroke is propagated to the intake expansion chamber 8 via the independent intake passage 6, where it is inverted into a positive pressure wave and reflected, and reaches each cylinder 4. Therefore, by matching the oscillation period of this pressure wave with the opening/closing period of the intake valve 11 in a specific operating range, in other words, an independent intake passage is created in which the negative pressure wave and its reflected wave propagate while the intake expansion chamber 8 has the required volume. By setting the length of 6 to a required length, an inertial effect of the intake air can be obtained and the filling efficiency of the intake air can be reduced.

In that case, the tank portion 13 constituting the intake expansion chamber 8 in the intake system structure 12 and the upstream portion 6 of each independent intake passage 6
The integrated intake pipe section 14 that constitutes the section a and the branched intake pipe section 15 that constitutes the downstream portion 6b of each independent intake passage 6,
Since each independent intake passage 6 is integrally formed by detouring around the intake expansion chamber 8 and using a part of the constituent wall of the intake expansion chamber 8 (tank portion 13), the independent intake passage 6 In order to obtain the required length and the required volume of the intake expansion chamber 8, these intake systems can be formed compactly and small, so that the above required length and the required volume can be achieved within a limited space (engine room). A sufficient required volume can be ensured, and the vehicle mountability can be improved.

Further, the fuel injection valve 19 is arranged in the vicinity of the downstream end of the branched intake pipe section 15, that is, on the downstream side of the independent intake passage 6, in order to supply the injected fuel to the combustion chamber 5 with good response while improving its atomization. Due to the fact that the fuel injection valve 19 is mounted facing toward the fuel injection valve 19, the tank portion 13 (intake expansion chamber 8) of the intake system structure 12 is located close to the central extension MAM of the fuel injection valve 19, but in this case, The intake system structure 12 is vertically divided into a lower divided body 12a and a lower divided body 12b at a position below the central extension line 9 in the tank portion 13, and both divided bodies 12a and 12b are combined. Therefore, the lower divided body 12b is connected to the engine body 1 with its 7 tank parts 16.
After mounting by tightening the bolts 17 from the side, the fuel injection valves 19 are inserted into the injection valve mounting holes 18 of each branch intake pipe section 15 of the lower divided body 12b from the direction of the central extension line, and the fuel supply pipes are inserted. Each fuel injection valve 19 is attached by fixing the fuel injection valve 20 to the lower divided body 12b. Thereafter, the lower divided body 12a is joined to the lower divided body 12b, and both 12a, 12 are tightened by tightening the bolts 22 from below.
By joining b together, not only can the upper and lower divided bodies 12a and 12tl be easily assembled, but also the fuel injection valve 19 can be easily assembled, resulting in a good assembly. Attachment can ensure sex.

Moreover, since the connection between the upper divided body 12a and the lower divided body 12b is performed by tightening the bolts 22 from below, good assembly can be ensured while maintaining the tank part 13 (intake expansion It is possible to form a bulge in the upper side of the engine side of the chamber 8), which has the advantage of ensuring a sufficient volume of the intake expansion chamber 8.

FIG. 4 shows a second embodiment of the present invention, in which, instead of obtaining the intake inertia effect in a specific operating range in each cylinder 4 in the first large embodiment, Each of these is an example of a device designed to enhance the intake inertia effect (the same parts as in the first embodiment (Figs. 1 to 3) are given the same reference numerals, and detailed explanation thereof will be omitted). .

That is, in the lower wall of the tank part 13 that constitutes the intake expansion chamber 8 in the intake system structure 12, there are communication holes 23, 23, .
, and open and close it to the multi-communication hole 23 [Filf
A fl valve 24 is provided, and the on-off valve 24 is controlled to open and close via an actuator by a control circuit that receives an output from an engine speed detection means, etc., and the on-off valve 24 is maintained in a closed state in a low engine speed range. The pressure waves generated in each cylinder 4 are propagated to and from the intake expansion chamber 8 via a relatively long independent intake passage 6, and as a result, the vibration period of this pressure wave and the intake valve opening/closing period are matched. Reduces the intake inertia effect in the low rotation range. On the other hand, in the 1 rotation range, the on-off valve 24 is opened to communicate the middle part of each independent intake passage 6 to the intake expansion chamber 8, thereby making the pressure wave propagation path relatively short, thereby reducing pressure waves in the high rotation range. The vibration period and the intake valve opening/closing period are matched to suppress the intake inertia effect.

Also in this case, as shown in the figure, the intake system structure 12
Each independent intake passage 6° 6... is integrally formed around the intake expansion chamber 8 using a part of the constituent wall of the intake expansion chamber 8 (tank portion 13), and the intake system structure body 12
The tank part 13 (intake expansion chamber 8) is formed by being divided into upper and lower parts at a position below the central extension line 9 of the fuel injection valve 19, that is, on the side of the branch intake pipe part 15, and is formed by dividing into upper and lower parts in the tank part 13 (intake expansion chamber 8). As in the case of , it is possible to improve the ease of mounting the intake system on a vehicle to obtain the intake inertia effect, and improve the ease of assembly.

In each of the above embodiments, a case has been described in which one fuel injection valve is mounted on the downstream side of the independent intake passage 6 near the lower FIt end of each branch intake pipe portion 15 in the intake system structure 12. The present invention can also be applied when the cylinder head 3 is mounted so as to face the intake boat 7 as the downstream end of the independent intake passage 6, and similarly, both the on-vehicle mountability and ease of assembly can be improved.

Furthermore, in addition to the above-described embodiments, the present invention also includes, for example, the second embodiment described above.
The tank part 13 of the intake system structure 12 in the embodiment (FIG. 4) is partitioned by a partition plate at its dividing plane to form two upper and lower intake expansion chambers, and as in the second embodiment, the tank part 13 of the intake system structure 12 is divided into two upper and lower intake expansion chambers. In addition to increasing the intake inertia effect in the rotation range, the on-off valve 2
An intake system in which pressure waves from other cylinders 4 act through the lower intake expansion chamber in the rotation range where cylinder 4 opens, thereby further increasing intake air filling efficiency by propagating pressure waves between cylinders, or Furthermore, the partition plate is provided with a communication hole that communicates the upper and lower intake expansion chambers, and further increases the intake air filling efficiency by utilizing intake pressure vibration between the upper and lower intake expansion chambers in the low rotation range. It is also applicable to systems.

Further, the present invention is not limited to a four-cylinder engine as in the above embodiment, but can also be applied to other multi-cylinder engines, such as a five-cylinder engine or a six-cylinder engine.
Of course, it can also be applied to cylinder engines.

(Effects of the Invention) As explained above, according to the present invention, an independent intake passage leading to each cylinder is integrally formed around the intake expansion chamber using a part of the wall constituting the intake expansion chamber. , the intake boat is installed downstream of the independent intake passage to ensure good fuel response while ensuring the required intake passage length and intake expansion chamber volume to obtain the intake inertia effect in a limited space. The intake expansion chamber, which is located on an extension of the center line of the fuel injector that is attached to face the opening of the combustion chamber, is divided into upper and lower parts below the center extension line. The fuel injection valve can be easily installed in the above state without being hindered by the enlarged chamber, and its assembly can be ensured. Therefore, it is possible to achieve both improvement in vehicle mountability of the intake system that exhibits the intake inertia effect and improvement in ease of assembly.

[Brief explanation of drawings]

The drawings illustrate embodiments of the invention, and FIGS.
1 is a longitudinal sectional side view taken along line I-I in FIG. 3, and FIG.
FIG. 3 is a partially cutaway plan view. FIG. 4 is a diagram corresponding to FIG. 1 showing the second embodiment. DESCRIPTION OF SYMBOLS 1... Engine body, 4... Cylinder, 6... Independent intake passage, 8... Intake expansion chamber, 12... Intake system structure, 12a... Upper division body, 12b... lower split body,
13...Tank part, 14...Integrated intake pipe part, 15.
... Branch intake pipe section, 19... Fuel injection valve.

Claims (1)

[Claims] (1) Each independent intake passage that independently connects the intake expansion chamber and each cylinder is integrally formed around the intake expansion chamber using a part of the wall constituting the intake expansion chamber. and an intake system for a multi-cylinder engine, wherein a fuel injection valve is provided downstream of each of the independent intake passages, and the intake expansion chamber is located on an extension of the center line of the fuel injection valve, wherein the intake expansion chamber An intake system for a multi-cylinder engine, characterized in that it is formed by being divided into upper and lower parts at a position below the central extension line.