JP2002070564A - Intake system for multicylinder internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optimal intake air efficiency by simplifying and miniaturizing a structure, and reducing the weight of an intake manifold having a variable intake mechanism and varying the capacity of a collector according to the operation state of an engine in the engine for an automobile which as a wide use rotation speed range and is difficult to hold a state of the favorable intake air efficiency in the whole range. SOLUTION: An intake channel of the intake manifold 1 is constituted of the collector 4, independent intake pipes 5a, 5b, and 5c, sub-collectors 7a and 7b partially jointly installed with the independent intake pipes 5a, 5b, and 5c and disposed on the upper part of an engine flange 6, and a plurality of communication valves controlling the communication. The communication valves are characterized in being opened/closed or continuously controlled based on the engine rotation speed and varying the collector capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake device for a multi-cylinder internal combustion engine, and more particularly to an intake device having a collector, a sub-collector, and a communication valve for controlling the opening and closing of the communication valve.

[0002]

2. Description of the Related Art Conventionally, as for an intake manifold of an internal combustion engine for a vehicle having two collectors, a technique of connecting two collectors by a pipe, and dividing one collector into two parts by a communication valve. Technology has been proposed. A conventional example of connecting two collectors is disclosed in Japanese Patent Publication No. 6-072533. This relates to an intake device for a V-type multi-cylinder engine that utilizes inertial supercharging and resonance supercharging. A technique for communicating the inside of one divided collector is disclosed in Japanese Patent Publication No. 6-100092. This is because a cylinder group composed of cylinders whose ignition order is not continuous is partitioned by a partition formed from one end to a multi-end, and is communicated by a communication passage provided in the partition.
And a sum of the two branch passages is longer than the communication passage. Both documents describe how to maintain the intake efficiency flat when the rotational speed changes over a wide range.

[0003]

In the case of an automobile engine, the rotational speed range is widely used. Therefore, it is difficult to maintain a state of high intake efficiency in the operating rotation speed region only by inertia supercharging. Therefore, a combination of inertial supercharging and resonance supercharging is absolutely necessary. To realize this, it is conceivable to provide a large number of intake pipes, but there is a disadvantage that the intake system becomes large.
Further, a method using a switching valve to make the variable intake length has been proposed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an intake manifold for a multi-cylinder internal combustion engine for an automobile, which has a simpler structure than the conventional intake manifold having a variable intake mechanism, and realizes space saving in an engine room due to its small size and light weight. It is to provide an intake manifold that can be used. It is another object of the present invention to obtain an optimal intake efficiency by combining a plurality of communication valves and opening and closing the communication valves in accordance with the operating condition of the engine.

[0005]

The above object can be attained by the following means. In an intake manifold for a multi-cylinder internal combustion engine, a collector, a plurality of parallel independent intake pipes branched from the collector, and a communication with the collector which are connected to the collector and are arranged in parallel at both outer edges of the plurality of independent intake pipe arrays. And a communication path for communicating the two sub-collectors at the other end opposite to the collector connection side of the sub-collector, and a communication path between the sub-collector and the communication path. And a single sub-collector communication valve for controlling communication of the sub-collector. Further, a communication valve for controlling communication between the collector and the sub-collector is controlled according to an operation state of the internal combustion engine, and a communication valve for controlling communication between the two sub-collectors is controlled according to an operation state of the internal combustion engine. That is the characteristic. A communication valve for controlling communication between the collector and the sub-collector and a communication valve for controlling communication between the two sub-collectors are controlled on / off or continuously according to an operation state of the internal combustion engine. There is.

A feature of the present invention is that part or all of the two sub-collectors are installed above a flange to be attached to an engine body.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An intake manifold for a multi-cylinder internal combustion engine according to the present invention will be described with reference to FIGS. The present invention relates to an intake manifold having a collector and an independent intake pipe. 1 to 5 are for a three-cylinder internal combustion engine, the present invention is not limited by the number of cylinders, the total displacement, and the like of the internal combustion engine.

FIG. 1 shows the structure of an intake manifold according to the present invention. Intake manifold 1 of the present invention
A throttle flange portion 3 for fixing a device 2 for controlling an amount of air taken into an internal combustion engine to an intake manifold 1, a collector 4 connected to the throttle flange 3, and independent intake pipes 5a, 5b branching from the collector 4;
b, 5c, and an engine flange portion 6 connected to the independent intake pipe and fixing the intake manifold 1 to a cylinder head of an internal combustion engine (not shown). And, it is connected to the collector 4 and is arranged in parallel with the independent intake pipes 5a, 5c and the engine (hereinafter referred to as EN).
G) (which is abbreviated as G), and a sub-collector 7a, 7b disposed above the flange 6, and a communication valve 8a for changing a collector capacity provided at a connection between the collector 4 and the independent intake pipes 5a, 5c. 8b and a communication valve 8c for communicating the sub-collectors 7a and 7b. The present invention has one feature in that the sub-collector 7a is arranged next to the independent intake pipe 5a and the sub-collector 7b is arranged next to the independent intake pipe 5c, so that the space can be used effectively and This has the effect of making the whole compact.

FIG. 2 shows the structure of the intake passage of the intake manifold 1 when the ENG rotation speed is low.
The communication valves 8a, 8b, 8c are all closed.
Although the throttle flange housing 3 is illustrated above the collector 4, the arrangement of the throttle valve 2TH and the throttle flange 3 as an air flow control device is not limited to the upper part. The air flowing from the throttle valve 2TH passes through a collector 4 having a part of a wall 9 having a rectifying effect having a curvature (hereinafter, referred to as a rectifying wall) as a constituent part thereof, and independent intake pipes 5a, 5b, 5c. Respectively. The sucked air is charged from a cylinder head (not shown) into an ENG cylinder (not shown).

In this embodiment, the ENG rotation speed N
When e is low speed, the opening / closing cycle of the intake valve (not shown) is long, and the average intake pipe length L1a (L1b, L1b, L2b) from the upper part of the collector 4 set to be synchronized with the opening / closing cycle to the independent intake pipe 5a (the same applies to 5b, 5c). L1c is also the same), thereby providing an effect of performing inertial supercharging, increasing the flow rate of air flowing into the cylinder, and increasing intake efficiency.

FIG. 3 shows the intake passage of the intake manifold 1 when the ENG rotation speed Ne is low to medium.
This is a case where the communication valves 8a and 8b are opened. The air flowing from the control device 2 passes through the collector 4 and is guided to the independent intake pipes 5a, 5b, and 5c, respectively, and is charged into an engine cylinder (not shown) from a cylinder head (not shown). At this time, the communication valves 8a and 8b are opened to allow the collector 4 to communicate with the sub-collectors 7a and 7b. In this embodiment, both of the communication valves 8a and 8c are open, but only one of them may be opened according to the operating state of ENG. When the communication valve is opened in this manner, when the ENG rotation speed Ne is low / medium speed, the opening / closing cycle of the intake valve is shorter than at low speed, and the length of the intake pipe synchronized with the opening / closing cycle is also lower at low speed. Length L
1a needs to be shorter. For this purpose, the capacity of the collector is increased by opening the communication valve 8a or 8b to make the sub-collectors 7a and 7b communicate with the collector 4, and the average intake pipe length synchronized with the opening and closing cycle is set to L2a.
(L2b, L2c), the flow rate of air flowing into the cylinder can be increased, and the intake efficiency can be increased.

FIG. 4 shows the intake passage of the intake manifold 1 when the ENG rotation speed Ne is medium to high, and the communication valve 8c is open. The air flowing from the control device 2 passes through the collector 4 and is supplied to the independent intake pipes 5a and 5a.
(b) and (5c), respectively, and are charged into an ENG cylinder (not shown) from a cylinder head (not shown).
At this time, since the communication valve 8c is open, the collector 4 communicates with the sub-collectors 7a and 7b. That is, the sub-collectors 7a and 7b are all in communication with the connected collector 4. When the ENG rotation speed Ne becomes high, the opening / closing cycle of the intake valve becomes shorter than that at the time of the medium speed, and the inertia supercharging performed at the time of the low speed to the medium speed cannot synchronize with the opening / closing cycle. The communication valves 8a, 8b, and 8c are all opened to further increase the collector capacity. Therefore, the independent intake pipe 5
The length L3a (L3b, L3c) of only the independent intake pipes having open ends at the branches of the collectors a, 5b, and 5c is the average intake pipe length at this time. By optimizing the diameter and length of the independent intake pipes 5a, 5b, 5c so that the pressure wave generated by opening and closing the intake valve is maximized at the position of the intake valve when the intake valve is closed, it flows into the cylinder. Thus, it is possible to obtain a resonance supercharging effect of increasing the flow rate of air to be generated and increasing intake efficiency.

FIG. 5 shows the relationship between the ENG and the operating state described with reference to FIGS. Here, the ENG rotation speed Ne, the open / close state of the communication valves 8a, 8b, 8c, and the length of the average independent intake pipe (L1a to L1c, L2a to L2c, L3a)
To L3c), intake efficiency (η1 to 3), and related diagram numbers. Specifically, the low speed range is about 2,000 rpm from the idle state in terms of the ENG rotation speed Ne, the low / medium speed range is about Ne = 2000-4000 rpm, and the middle / high speed range is about 4000-6000 rpm. The average intake pipe length in each state is L1a-c, L2a-c, L3
In a to c, the magnitude relation is L1a>L2a> L3a
(In the case of the independent intake pipe 5a, the same applies to the intake pipes 5b and 5c). FIG. 1 shows these average intake pipe lengths as a whole. In this way, the opening / closing control of the communication valve can change the equivalent average intake pipe length to improve the intake efficiency.

FIG. 6 shows a control flow of these communication valve operations. In step S62, the EN attached to ENG
The rotation speed signal from the G rotation detection means (not shown) is fetched, and in step S64, the area of the fetched ENG rotation speed Ne is determined. When Ne is determined to be in the idle / low rotation region (in the case of FIG. 5A), the communication valves 8a to 8c
Indicates the fully closing operation, and when Ne is determined to be in the low / medium rotation region (in the case of FIG. 5B), the communication valves 8a and 8b are opened and 8c
Performs the closing operation, and when Ne is in the middle / high-speed rotation region (in the case of FIG. 5C), the communication valves 8a to 8c also fully open.
Thus, the communication valve is so-called ON / OFF control of either fully closed or fully open. However, the control of the communication valve may be performed by a predetermined function.

FIG. 7 shows an example of this case. S72 in FIG. 7A is a control function for the communication valve 8a, which controls the opening by the valve operating means VDa. S74 is a control function for the communication valve 8b, and the opening degree is controlled by the valve operating means VDb. S76 is a control function for the communication valve 8c, and the opening degree is controlled by the valve operating means VDc. Generally, fa (Ne) = fb (Ne), but different functions may be used. These examples are shown in FIG. In this example, as the ENG rotation speed Ne increases,
The opening of the communication valve 8a is controlled by the function fa (Ne), the opening of the communication valve 8b is controlled by the function fb (Ne), and the opening of the communication valve 8c is controlled by the function fc (Ne). You. That is, from the point a, the communication valve 8
This indicates that the opening of the communication valve 8b is controlled from point b and the opening of the communication valve 8c is controlled from point c.

FIG. 7B shows the case where the communication valve is ON / OFF controlled by a dotted line. At points a and b, the communication valves are all closed. At point b, the communication valves 8a and 8b are fully opened. Then, the communication valve 8c is fully opened. Also, here, the case where the communication valves 8a and 8b start to open at the point b, but there may be various cases as a control function.
When the on / off control shown in FIG. 5 is replaced with continuous control, fa (Ne) = fb (Ne) in FIG. 7B. However, the communication valves 8a and 8b need not always be controlled simultaneously.

FIG. 8 shows the above-mentioned engine operating condition (EN
G rotation speed) indicates the intake efficiency to the cylinder with respect to the engine rotation speed when the communication valves 8a, 8b, and 8c are opened. By closing all of the communication valves, the intake efficiency η1 to the cylinder when the engine speed is low is low.
And opening the communication valves 8a and 8b to increase the intake efficiency η2 to the cylinder when the engine speed is medium speed, and also opening all the communication valves 8c to increase the intake efficiency η3 to the cylinder when the engine speed is high speed. As a result, the intake efficiency can be improved in the entire rotation speed range. As described above, the number of the communication valves is two, and the sub-collector is provided in parallel with the independent intake pipe. Therefore, the intake apparatus can be configured extremely compactly, and the efficient intake apparatus can be configured.

[0018]

According to the present invention, the space in the engine room can be reduced by arranging the sub-collector in parallel with the independent intake pipe and arranging the communication passage above the engine flange to open and close the communication valve. Can be achieved. Also,
Since the collector capacity is varied, the intake efficiency can be improved even when the operating condition of the engine changes.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an intake passage of an intake manifold explaining the present invention.

FIG. 2 is a configuration diagram of an intake passage of an intake manifold when an engine speed is low.

FIG. 3 is a configuration diagram of an intake passage of an intake manifold when an engine speed is a medium speed.

FIG. 4 is a configuration diagram of an intake passage of an intake manifold when the engine speed is high.

FIG. 5 is a diagram illustrating engine speed, communication valve operation, average independent intake pipe length, and the like.

FIG. 6 is a flowchart for explaining a control operation of a communication valve.

FIG. 7 is a schematic explanatory diagram of an operation in the case of on / off control and continuous control based on a control function of a communication valve.

FIG. 8 is a diagram showing a relationship between an engine speed and intake efficiency.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Intake manifold, 2 ... Air flow control device, 2TH ... Throttle valve, 3 ... Throttle flange, 4
... collector, 5a, 5b, 5c ... independent intake pipe, 6 ... engine flange, 7a, 7b ... sub-collector, 8a, 8
b, 8c: communication valve, 9: rectifier VDa, VDb, VDc
... Opening / closing drive means for the communication valves 8a, 8b, 8c

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G031 AA15 AA28 AB04 AC01 BA07 BA14 BA17 BA18 BA19 BB11 BB14 BB16 DA32 DA36 EA02 EA03 FA03 GA03 GA05 HA01 HA02 HA04 HA10

Claims (8)

[Claims] 1. An intake system for a multi-cylinder internal combustion engine, comprising: a collector; a plurality of parallel independent intake pipes branching from the collector; and a plurality of independent intake pipes connected to the collector and arranged in parallel at both outer edges of the arrangement of the plurality of independent intake pipes. Two sub-collectors each having a communication valve for controlling communication with the collector, a communication path for communicating the two sub-collectors at the other end opposite to the collector connection side of the sub-collector, and the communication path And a single sub-collector communication valve for controlling communication between the sub-collectors. 2. The intake device for a multi-cylinder internal combustion engine according to claim 1, wherein a communication valve for controlling communication between the collector and the sub-collector is controlled according to an operation state of the internal combustion engine. 3. The intake system for a multi-cylinder internal combustion engine according to claim 1, wherein a communication valve for controlling communication between the two sub-collectors is controlled according to an operation state of the internal combustion engine. 4. The intake system for a multi-cylinder internal combustion engine according to claim 2, wherein a communication valve for controlling communication between the collector and the sub-collector is on / off controlled according to an operation state of the internal combustion engine. . 5. An intake system for a multi-cylinder internal combustion engine according to claim 3, wherein a communication valve for controlling communication between said two sub-collectors is on / off controlled according to an operation state of said internal combustion engine. . 6. An intake system for a multi-cylinder internal combustion engine according to claim 1, wherein a part or all of said two sub-collectors are installed above a flange for attaching said intake pipe to an engine body. 7. The intake system for a multi-cylinder internal combustion engine according to claim 2, wherein a communication valve for controlling communication between the collector and the sub-collector is continuously controlled according to an operation state of the internal combustion engine. . 8. An intake system for a multi-cylinder internal combustion engine according to claim 3, wherein a communication valve for controlling communication between said two sub-collectors is continuously controlled according to an operation state of said internal combustion engine. .