JP2002256873A - Changeable intake system of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a changeable intake system of an internal combustion engine capable of obtaining more effect by a simple system. SOLUTION: The downstream side of a throttle valve 4 installed in an intake passage 2 of an internal combustion engine 9 is connected to an intake manifold 8 by way of a surge tank 5, the surge tank 5 comprises a first surge tank 5A connected to the intake passage 2 on the throttle valve side and the intake manifold 8 and a second surge tank 5B communicating with the first surge tank 5A through a linkage passage 7. The intake passage 2 on the upstream side over the throttle valve 4 is formed with two channels of intake passages 2A, 2B, the linkage passage 7 is opened or shut by a first valve V1, one intake passage 2B is opened or shut by a second valve V2, and the first and the second valves V1, V2 are controlled to be opened or shut according to the operating condition of the internal combustion engine 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable intake system for an internal combustion engine, and more particularly to a variable intake system for an internal combustion engine capable of greatly improving the performance of the internal combustion engine and reducing the cost.

[0002]

2. Description of the Related Art It has been known to utilize the dynamic effect of intake air as one method for improving the output of an internal combustion engine. As the dynamic effect of the intake air, an intake resonance effect utilizing resonance of intake vibration in an intake pipe is known. In order to realize this intake resonance effect in a multi-cylinder internal combustion engine, cylinders in which intake operation is not continuous are grouped, the intake passage is branched into a plurality of branch passages corresponding to each cylinder group, and It is common practice to provide a surge tank acting as a resonance chamber on the downstream side.

However, if the intake passage is divided into a plurality of parts and a surge tank is simply provided in the intake passage, the resonance of the intake vibration with respect to the intake system may be caused by a certain engine speed or a predetermined engine speed. In the internal combustion engine for automobiles, which can be obtained only in a limited range of rotation speed around the center and is operated in a wide rotation speed range from low speed to high speed, a resonance effect is obtained over the entire operation range I couldn't do that.

Therefore, a multi-cylinder internal combustion engine is provided with a surge tank divided into two rooms by a partition wall, and each room of the surge tank is connected to a cylinder whose intake order is not continuous by an independent intake passage. The intake passage connected to the partition is divided into two branch passages by a partition wall, and a throttle valve is provided for each of the branch passages. Further, first and second valves are provided for the partition wall and the partition wall, respectively, so that both sides of the partition wall and the partition wall communicate with each other. The first valve is opened in a low-load operation range of the engine, and the opening and closing of the first and second valves are controlled in accordance with the magnitude of the engine speed in a high-load operation range of the engine. An intake device has been proposed (Japanese Unexamined Patent Publication No.
0-169627).

[0005]

However, in the above-described intake device, the throttle valve is provided in each of the two branch passages branched by the partition, and the partition wall of the surge tank and the intake passage are provided. Since the opening and closing of the first and second valves respectively provided on the partition walls are independently controlled by the first and second actuators, there is a problem that the apparatus cost is high.

In view of the above, the present invention demands a further improvement in the performance of an internal combustion engine for an automobile, and therefore, there is a limit in a conventional variable intake system. Although a higher performance can be achieved by combining them, in view of the necessity of reducing the cost of the apparatus, it is desirable to provide a variable intake system for an internal combustion engine that can obtain a greater effect with a simple system. The purpose is.

[0007]

A feature of the variable intake system for an internal combustion engine of the present invention that achieves the above object is that a downstream side of a throttle valve provided in an intake passage of the internal combustion engine is connected to an intake manifold via a surge tank. In that the surge tank is composed of a first surge tank connected to the intake passage on the throttle valve side and the intake manifold, and a second surge tank connected to the first surge tank by a communication passage.
The point that an on-off valve is provided, the intake passage on the upstream side of the throttle valve is formed by two systems of intake passages, and the second on-off valve is provided in one intake passage, 1
And the second on-off valve is controlled to be opened and closed by a vacuum motor, and each vacuum motor is opened and closed by one electric-type negative pressure switching valve, and is operated by a negative pressure from a vacuum tank provided in a vehicle equipped with an internal combustion engine. The point that the same operation is performed and that the electric negative pressure switching valve is configured to open the first and second on-off valves when the rotation speed of the internal combustion engine is equal to or higher than a predetermined value.

With this configuration, two vacuum motors can be controlled by one electric negative pressure switching valve, and the capacity of the surge tank and the two intake passages of the duct length and the duct diameter of the intake passage are controlled. Since the resonance element can be changed, engine performance can be greatly improved,
The effect that the cost of the system can be reduced can be obtained.

[0009]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows the overall configuration of a variable intake system for an internal combustion engine according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an air cleaner, and an intake passage 2 connected to a surge tank 5 is connected to a clean side of the air cleaner 1. A throttle valve 4 for controlling the amount of intake air is provided just upstream of the surge tank 5 in the intake passage 2.
The inside of the intake passage 2 on the upstream side of the throttle valve 4 is divided into a first intake passage 2A and a second intake passage 2B by a partition wall 3.
And a second on-off valve V2 is provided inside the second intake passage. When the second on-off valve V2 is closed, the intake air does not flow through the second intake passage 2B.

On the other hand, the inside of the surge tank 5 is divided by a partition wall 6 into a first surge tank 5A and a second surge tank 5B, and the partition wall 6 is provided with a first on-off valve V1. A communication path 7 is provided. The first surge tank 5 </ b> A is connected to the above-described intake passage 2 and to the intake manifold 8 of the internal combustion engine 9. Therefore, when the first on-off valve V1 is opened, the capacity of the surge tank 5 increases, and when the first on-off valve V1 is closed, the capacity of the surge tank 5 decreases.

The first on-off valve V1 is controlled to open and close by a first vacuum motor 11, and the second on-off valve V2 is controlled by a second
Is controlled by the vacuum motor 12. First
The driving source of the second vacuum motors 11 and 12 is a negative pressure in a vacuum tank 14 mounted on a vehicle. The negative pressure in the vacuum tank 14 is guided to both the first and second vacuum motors 11 and 12 by a negative pressure introducing pipe 15 provided with an electric negative pressure switching valve (hereinafter referred to as VSV) on the way. It has become. Therefore, in this embodiment, two vacuum motors 11 and 12 operate simultaneously by one VSV 13 operation.

The opening / closing control of the VSV 13 is performed by an ECU (engine control unit) 10 according to the operating state of the internal combustion engine 9. In this embodiment, E
The engine speed NE from a speed sensor (not shown) is input to the CU 10 as a parameter indicating the operating state of the internal combustion engine 9. The ECU 10 determines that the internal combustion engine 9 is in the low-speed operation range when the engine speed NE is equal to or lower than the predetermined speed NE1 and outputs a close signal to the VSV 13. It determines that the vehicle is in the operating range, and outputs an open signal to the VSV 13.

In the state shown in FIG. 1, 1500 rpm is input from the rotation sensor to the ECU 10 as the rotation speed of the internal combustion engine. At this time, the ECU 10 determines that the internal combustion engine 9 is in the low speed operation range, and In response, a close signal is output. When the VSV 13 is closed by the close signal, the first and second on-off valves 11 and 12 are both closed, and the intake air that has passed through the air cleaner 1 is, as shown by an arrow in FIG. Flows into the first surge tank 5A of the surge tank 5 only through the intake passage 2A. In this state, the intake air flowing into the first surge tank 5A of the surge tank 5 is drawn into the internal combustion engine 9 from the intake manifold 8 without flowing into the second surge tank 5B.

FIG. 2 shows the operation of the variable intake system in the variable intake system of the internal combustion engine according to the first embodiment described with reference to FIG. The same components as those in FIG. 1 are denoted by the same reference numerals. The rotational speed of the internal combustion engine 9 is in a high speed operation range,
For example, in this embodiment, when 3000 rpm is reached, an open signal is output from the ECU 10 to the VSV 13. The VSV 13 is opened by the opening signal, and the negative pressure in the vacuum tank 14 is guided to the vacuum motor 11 and the vacuum motor 12. Due to this negative pressure, the vacuum motor 11 and the vacuum motor 12 open the on-off valves V1 and V2, respectively.

When the first and second on-off valves 11 and 12 are both opened, the intake air passing through the air cleaner 1 is supplied to the first intake passage 2 of the intake passage 2 as shown by an arrow in FIG.
A flows into the first surge tank 5A of the surge tank 5 through both the first intake passage A and the second intake passage 2B. In this state, since the first surge tank 5A and the second surge tank 5B of the surge tank 5 communicate with each other through the communication path 7, the capacity of the surge tank 5 is increased. Therefore, the intake air flowing through the intake passage 2 is in the same state as that flowing into the surge tank 5 having a large capacity, and the intake manifold 8
From the internal combustion engine 9.

As described above, when the second on-off valve 12 is opened, the intake passage 2 has two systems of the first intake passage 2A and the second intake passage 2B.
This is equivalent to an increase in the diameter of the duct and a reduction in the duct length related to engine performance. And by increasing the diameter of the duct, the engine performance on the high-speed side where a large amount of flow flows improves,
By shortening the duct length, the peak of the engine performance on the low speed side moves to the high speed side, and the engine performance on the medium speed is improved. Also,
When the first on-off valve 11 opens, the capacity of the surge tank 5 increases, and the engine performance on the high-speed side improves.

FIG. 3 shows two on-off valves V1, V shown in FIG.
2 with respect to the engine speed NE (rpm) when both are opened, when both are closed, and when the on / off valve in the surge tank is opened and the on / off valve on the intake passage is closed. The change in the volume efficiency ηV was determined by experiment. In FIG. 3, the characteristics when both the on-off valves V1 and V2 are closed are plotted in a diamond shape, and the characteristics when the on-off valve V1 is opened and the on-off valve V2 is closed are plotted in a square, and the on-off valve V1 is plotted. ,
The characteristics when both valves V2 are opened are plotted as triangles.

As can be seen from FIG. 3, in the low-speed rotation range of the engine until the engine speed NE reaches the predetermined speed NE1,
The volume efficiency is the highest when both the on-off valves V1 and V2 are closed, and in the high-speed rotation range of the engine where the engine speed NE exceeds a predetermined speed NE1, the volume when both the on-off valves V1 and V2 are open. Efficiency was the highest. As a result of this experiment, the value of the predetermined rotation speed NE1 was approximately 2500 rpm.

From the results of this experiment, in this embodiment, the ECU
The engine speed at which 10 outputs a close signal to the VSV 13 is set to a value detected by a speed sensor of 2500 rpm or less,
It is assumed that the engine speed at which the open signal is output is when the value detected by the speed sensor is greater than 2500 rpm. As described above, since the on-off valves V1 and V2 only need to be closed or opened at a predetermined rotational speed NE1 as a boundary, the present invention is mounted on a vehicle as a drive source of the on-off valves V1 and V2. The negative pressure in the vacuum tank 14 is used, and the negative pressure is used by only one VSV 13 to open and close the on-off valves V1 and V1.
2 is supplied to the vacuum motors 11 and 12 for opening and closing, and as a result, the effect of two variable intakes can be obtained, and the configuration is simple and the cost can be reduced.

FIG. 4 shows the overall configuration of a second embodiment of the variable intake system for an internal combustion engine according to the present invention. As shown in FIG. 1, two variable intake systems are provided when the engine speed is lower than a predetermined value. It also shows the state of the on-off valve. The second embodiment differs from the variable intake system for an internal combustion engine of the first embodiment only in the configuration of the surge tank 5. Therefore, the second
In FIG. 4 showing the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the first embodiment, the surge tank 5 is divided by the partition wall 6 into the first surge tank 5A and the second surge tank 5B. On the other hand, in the second embodiment,
The surge tank 5 has a separate first surge tank 5A and a second surge tank 5A.
Of the surge tank 5B. And the first
The first surge tank 5A and the second surge tank 5B
Are connected by a communication path 7 provided with an on-off valve V1.

In the variable intake system for an internal combustion engine of the second embodiment configured as described above, the first surge tank 5
A and the second surge tank 5B are provided independently.
And the degree of freedom of arrangement of the second surge tanks 5A and 5B in the engine room is increased. With the variable intake system of the internal combustion engine of the second embodiment, the same performance as that of the variable intake system of the internal combustion engine of the first embodiment can be obtained.

FIG. 5 shows a partial configuration of a third embodiment of the variable intake system for an internal combustion engine according to the present invention. Similar to FIG. 1, two variable intake systems when the engine speed is lower than a predetermined value are shown. It also shows the state of the on-off valve. The third embodiment differs from the variable intake system for an internal combustion engine of the first embodiment only in the configuration of the intake passage 2. Therefore, in FIG. 5 showing the third embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted, and the control of the first and second on-off valves V1 and V2 will be described. The illustration of the system is omitted.

In the first embodiment, a partition 3 for partitioning the inside of the intake passage 2 is not provided immediately after the air cleaner 1, and the partition 3 is located at a predetermined distance from the air cleaner 1.
Was formed. On the other hand, in the third embodiment, a partition 3 that partitions the inside of the intake passage 2 is provided immediately after the air cleaner 1, and the partition 3 is interrupted at a position substantially upstream of the throttle valve 4.

With the variable intake system for an internal combustion engine of the third embodiment configured as described above, the same performance as that of the variable intake system for an internal combustion engine of the first embodiment can be obtained. FIG. 6 shows a partial configuration of a fourth embodiment of the variable intake system for an internal combustion engine according to the present invention. Similar to FIG. 1, when the engine speed is lower than a predetermined value, two open / close valves are opened. The state is also shown. The fourth embodiment is different from the variable intake system of the internal combustion engine of the first embodiment only in the configuration of the intake passage 2. Therefore, in FIG. 6 showing the fourth embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.
The illustration of the control system of the on-off valves V1 and V2 is omitted.

In the first embodiment, the intake passage 2 is divided by the partition 3 into the first intake passage 2A and the second intake passage 2B. On the other hand, in the fourth embodiment, the intake passage 2 is composed of separate first intake passages 2A and second intake passages 2B. The first intake passage 2 </ b> A and the second intake passage 2 </ b> B are separate from a predetermined position on the downstream side of the air cleaner 1 and merge at the upstream side of the throttle valve 4.

In the variable intake system for an internal combustion engine according to the fourth embodiment having the above-described structure, the first intake passage 2A and the second intake passage 2B are separate bodies. The degree of freedom of arrangement of the second intake passages 2A and 2B in the engine room is increased. With the variable intake system of the internal combustion engine of the fourth embodiment, the same performance as that of the variable intake system of the internal combustion engine of the first embodiment can be obtained.

[Brief description of the drawings]

FIG. 1 shows the overall configuration of a first embodiment of a variable intake system for an internal combustion engine according to the present invention, in which the states of two on-off valves when the engine speed is lower than a predetermined value are combined. FIG.

FIG. 2 is an overall configuration diagram showing a state of two on-off valves when the engine speed is higher than a predetermined value in the variable intake system of FIG. 1;

FIG. 3 shows a state in which the two on-off valves shown in FIG. 1 are both open and closed, and when the on-off valve in the surge tank is open and the on-inlet-side on-off valve is closed. FIG. 4 is a diagram illustrating a change in volume efficiency with respect to an engine speed.

FIG. 4 shows the overall configuration of a variable intake system for an internal combustion engine according to a second embodiment of the present invention, in which the states of two on-off valves when the engine speed is lower than a predetermined value are combined. FIG.

FIG. 5 is a partial configuration diagram showing a partial configuration of a third embodiment of the variable intake system for an internal combustion engine of the present invention.

FIG. 6 is a partial configuration diagram showing a partial configuration of a fourth embodiment of the variable intake system for an internal combustion engine of the present invention.

[Explanation of symbols]

 2: intake passage 2A: first intake passage 2B: second intake passage 3: partition wall 4: throttle valve 5: surge tank 5A: first surge tank 5B: second surge tank 6: partition wall 7: continuous Passage 8 ... Intake manifold 9 ... Internal combustion engine 10 ... ECU (engine control unit) 11 ... First vacuum motor 12 ... Second vacuum motor 13 ... VSV (electric negative pressure switching valve) 14 ... Vacuum tank V1 ... First on-off valve V2: Second on-off valve

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (Reference) F02M 35/104 F02M 35/10 102M F-term (Reference) 3G031 AA15 BA07 BA08 BA14 BA17 BB04 BB09 BB11 BB14 BB16 DA32 DA37 DA39 EA02 EA09 EA10 FA03 HA01 HA02 HA04 HA10 3G065 AA07 CA00 CA23 DA02 EA11 EA12 FA14 GA10 HA02 HA06 KA03

Claims (8)

[Claims] 1. A downstream side of a throttle valve provided in an intake passage of an internal combustion engine is connected to an intake manifold via a surge tank, and the surge tank is connected to an intake passage on the throttle valve side and the intake manifold. 1 surge tank,
The first surge tank is constituted by a second surge tank which communicates with a communication passage. The intake passage on the upstream side of the throttle valve is formed by two systems of intake passages. And a second on-off valve is provided on one of the two intake passages, and the first and second on-off valves are controlled to open and close according to the operating state of the internal combustion engine. A variable intake system for an internal combustion engine, characterized in that: 2. A downstream side of a throttle valve provided in an intake passage of an internal combustion engine is connected to an intake manifold via a surge tank, and the surge tank is connected to the intake passage on the throttle valve side and the intake manifold. 1 surge tank,
The first surge tank is constituted by a second surge tank which communicates with a communication passage. The intake passage on the upstream side of the throttle valve is formed by two systems of intake passages. , And a second on-off valve is provided on one of the two intake passages. The first and second on-off valves are provided in a vehicle equipped with the internal combustion engine, respectively. A variable intake system for an internal combustion engine, wherein opening and closing are controlled by a vacuum motor using a negative pressure in a vacuum tank in accordance with an operation state of the internal combustion engine. 3. A downstream side of a throttle valve provided in an intake passage of the internal combustion engine is connected to an intake manifold via a surge tank, and the surge tank is connected to the intake passage on the throttle valve side and the intake manifold. 1 surge tank,
The first surge tank is constituted by a second surge tank which communicates with a communication passage. The intake passage on the upstream side of the throttle valve is formed by two systems of intake passages. And a second on-off valve is provided on one of the two intake passages, and the first and second on-off valves are respectively controlled to be opened and closed by a vacuum motor. Each vacuum motor is connected via one electric negative pressure switching valve to a vacuum tank provided in a vehicle equipped with the internal combustion engine, and a negative pressure guided by the opening / closing operation of the electric negative pressure switching valve provides: A variable intake system for an internal combustion engine, wherein the variable intake system is configured to perform the same operation according to an operation state of the internal combustion engine. 4. A downstream side of a throttle valve provided in an intake passage of the internal combustion engine is connected to an intake manifold via a surge tank, and the surge tank is connected to the intake passage on the throttle valve side and the intake manifold. 1 surge tank,
The first surge tank is constituted by a second surge tank which communicates with a communication passage. The intake passage on the upstream side of the throttle valve is formed by two systems of intake passages. And a second on-off valve is provided on one of the two intake passages, and the first and second on-off valves are respectively controlled to be opened and closed by a vacuum motor. Each of the vacuum motors is connected to a vacuum tank provided in a vehicle equipped with the internal combustion engine through one electric negative pressure switching valve, and the same is applied by a negative pressure guided by an opening / closing operation of the electric negative pressure switching valve. The electric negative pressure switching valve is configured to open the first and second on-off valves when the operating state of the internal combustion engine is in a high load region. Features and Internal combustion engine variable intake system of that. 5. A downstream side of a throttle valve provided in an intake passage of the internal combustion engine is connected to an intake manifold via a surge tank, and the surge tank is connected to an intake passage on the throttle valve side and the intake manifold. 1 surge tank,
The first surge tank is constituted by a second surge tank which communicates with a communication passage. The intake passage on the upstream side of the throttle valve is formed by two systems of intake passages. And a second on-off valve is provided on one of the two intake passages, and the first and second on-off valves are respectively controlled to be opened and closed by a vacuum motor. Each vacuum motor is connected to a vacuum tank provided in a vehicle equipped with the internal combustion engine through one electric negative pressure switching valve, and the negative pressure guided by the opening / closing operation of the electric negative pressure switching valve causes The electric negative pressure switching valve is configured to open the first and second on-off valves when the rotation speed of the internal combustion engine is equal to or higher than a predetermined value. Features Internal combustion engine variable intake system of that. 6. The variable intake system for an internal combustion engine according to claim 1, wherein the first and second surge tanks divide one surge tank by a partition wall. A variable intake system for an internal combustion engine, wherein the variable intake system is formed. 7. The variable intake system for an internal combustion engine according to claim 1, wherein the two intake passages are formed by partitioning one intake pipe with a partition wall. A variable intake system for an internal combustion engine, characterized in that: 8. The variable intake system for an internal combustion engine according to claim 7, wherein the partition wall is formed at a position downstream of a portion of the intake pipe connected to an air cleaner by a predetermined distance. Variable intake system for internal combustion engines.