JP2004011540A - Intake flow control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To drive a valve installed in an intake passage by a small torque in order to control the gas flow in a cylinder in an intake flow control device of an internal combustion engine. <P>SOLUTION: A partition plate 12 is installed on a port part of an intake system, and an intake passage is divided into upper and lower parts. Two butterfly-shaped control valves 13a and 13b to open/close a lower passage c2 are installed in the lower passage c2 demarcated by the partition plate 12. The control valves 13a and 13b are rotated in a separating direction from each other when the valves are opened. The downstream side control valve 13b is opened after the upstream side control valve 13a is opened when the control valves are opened from the closed condition. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an intake flow control device for an internal combustion engine, and more particularly, to an intake flow control device including a valve for narrowing an intake passage for generating a strong tumble flow of air in a cylinder.
[0002]
[Prior art]
As a device for generating a strong tumble flow of air in a cylinder, a partition plate is installed at a port portion of an intake system to partition an intake passage into upper and lower portions. Some have a butterfly valve for opening and closing the lower passage. In such a tumble flow control device, the tumble flow of air can be enhanced by closing the lower passage by the valve and allowing air to flow into the cylinder only from the upper passage of the partition plate.
[0003]
[Problems to be solved by the invention]
However, in the above-described apparatus, the pressure provided by the air flow acts on the valve provided in the lower passage of the partition plate together with the suction negative pressure. Therefore, when the valve is driven against the flow of air (generally, when the valve is opened), a torque that exceeds the combined force of the suction negative pressure and the pressure is required. For this reason, there is a problem that the valve motor becomes large and the cost increases.
[0004]
Here, as a device for controlling the swirl flow of air, there is known a device in which a port portion is partitioned by a partition plate and valves are installed in each of the passages partitioned by the partition plate (Japanese Patent Laid-Open No. 07-0707). No. 102983). Even if valves are provided in the passages on each side of the partition plate, both the suction negative pressure and the pressure due to the flow of air act on one valve, so that the above-mentioned problem is solved. It is not possible.
[0005]
Therefore, an object of the present invention is to make it possible to drive a valve installed in an intake passage to control gas flow in a cylinder with a small torque in an intake flow control device for an internal combustion engine.
[0006]
[Means for Solving the Problems]
For this reason, according to the first aspect of the present invention, the intake flow control device for the internal combustion engine is provided with a partition plate, which is installed along a flow of air at a port portion of the intake system and partitions the intake passage, and the partition plate. A valve for opening and closing the one-side passage, which is installed in the one-side passage partitioned, and driving means for driving the valve to open and close the one-side passage; A butterfly-type first valve and a butterfly-type second valve installed downstream of the first valve are provided as valves, and the first and second valves are driven by the driving unit. They were rotated in opposite directions.
[0007]
In the invention described in claim 2, the intake passage is vertically divided by the partition plate, and the first and second valves are installed in a lower passage partitioned by the partition plate.
In the invention described in claim 3, the first and second valves are rotated in a direction in which the first and second valves are separated from each other when the valves are opened.
[0008]
In the invention described in claim 4, when the first and second valves are both opened from the closed state, the second valve is opened after the first valve is opened.
In the invention according to claim 5, when closing the first and second valves from the open state, the first valve is closed after the second valve is closed.
In the invention described in claim 6, as the drive modes of the first and second valves, a first mode in which these valves are both kept closed, and a first mode in which the second valves are closed. A second mode in which the opening of the valve is changed, a third mode in which the opening of the second valve is changed while the first valve is open, and a state in which both the first and second valves are open. And a fourth mode.
[0009]
In the invention described in claim 7, the first and second valves are driven in the order of the first, second, third, and fourth modes in accordance with an increase in engine load.
[0010]
【The invention's effect】
According to the invention according to claim 1, as a valve for opening and closing one side of the passage defined by the partition plate, a butterfly-shaped first valve and a butterfly-shaped valve are provided downstream of the first valve. Second valves were provided, and these valves were rotated in opposite directions by the driving means. For this reason, the opening timing of the first and second valves is shifted forward and backward, and the one that is driven against the flow of air is opened, and then the other valve is opened. These valves can be opened with little force from one of the pressures.
[0011]
According to the invention according to claim 2, the intake passage is vertically divided by the partition plate, and the first and second valves are provided in the lower passage, so that the tumble flow of air can be strengthened.
According to the third aspect of the invention, when both the first and second valves are open, the valves can be prevented from overlapping the partition plate, so that the flow path resistance can be suppressed.
[0012]
According to the fourth aspect of the present invention, when the first and second valves are both opened from the closed state, the first valve is opened first, so that the first valve does not receive the force from the suction negative pressure. The valve can be opened.
According to the invention according to claim 5, when the first and second valves are both closed from the open state, by closing the second valve first, when both valves are closed, these valves are closed. It is possible to prevent a negative pressure from remaining in the intervening space, and to prevent an increase in torque required when the first valve is opened next time.
[0013]
According to the invention according to claim 6, in the second mode in which the opening degree of the first valve is changed while the second valve is closed, the passage on one side of the partition plate is shut off, and the air to the cylinder is released. The intake air amount can be increased while maintaining a high inflow speed of the air. In addition, the amount of intake air can be further increased by the third mode in which the opening degree of the second valve is changed while the first valve is open.
[0014]
According to the invention of claim 7, it is possible to cause the engine to take in a necessary amount of air in response to an increase in load, and to form a gas flow necessary for stable combustion.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of a direct-injection gasoline engine (hereinafter, referred to as “engine”) 1 according to an embodiment of the present invention, showing a configuration around a combustion chamber. The cylinder head 3 fixed on the cylinder block 2 is provided with two intake port portions 4 and two exhaust port portions 5 arranged in the cylinder arrangement direction. An intake valve 6 for opening and closing the port 4 is interposed in the intake port 4, while an exhaust valve for opening and closing the port 5 is provided in the exhaust port 5. 7 are interposed. An ignition plug 10 is provided on the cylinder head 3 so as to face the upper center of a combustion chamber 9 formed by the cylinder head 3 and a piston 8 inserted into the cylinder block 2. In addition, a high-pressure injector (not shown) is provided between the two intake valves 6 in the cylinder head 2.
[0016]
Here, a tumble flow control device 11 as an intake flow control device according to the present embodiment is installed in the port portion 4 of the intake system. The tumble flow control device 11 increases the flow velocity of the air, so that a strong tumble flow Ft of air is formed in the cylinder. The injector directly injects fuel into a cylinder during stratified charge combustion during a compression stroke and during homogeneous charge combustion during an intake stroke. An engine controller, which will be described later, switches between these combustion modes according to the operating state, and controls the injection timing of the injector.
[0017]
FIG. 2 is a configuration diagram of the tumble flow control device 11 according to the present embodiment. The tumble flow control device 11 includes a rectangular flat plate 12 as a partition plate, and two butterfly-shaped control valves 13a and 13b as first and second valves. The flat plate 12 is installed in the port portion 4 of the intake system so as to follow the flow of air, and divides the intake passage into two upper and lower partial passages c1 and c2. In the lower passage c2 defined by the flat plate 12, an upstream control valve 13a as a first valve is installed on the upstream side, and a downstream control valve 13b as a second valve is installed on the downstream side. I have. Each of these control valves 13a and 13b is configured by connecting rotation shafts 132a and 132b to semicircular valve bodies 131a and 131b. The upstream control valve 13a is installed adjacent to the upstream side of the flat plate 12, and the rotation shaft 132a extends to the outside through the port side wall. On the other hand, the downstream control valve 13b is installed adjacent to the downstream side of the flat plate 12, and the rotating shaft 132b extends to the outside through the port portion side wall.
[0018]
Rotary shafts 132a, 132b of the control valves 13a, 13b are connected to output shafts (not shown) of motors 14a, 14b as driving means, and are independently and at an arbitrary angle within a range of 0 to 90 °. It can be displaced. These motors 14a and 14b operate based on a command signal from the engine controller 15. The crank angle position detection signal of the crank angle sensor 16 and the accelerator position detection signal of the accelerator sensor 17 are input to the engine controller 15. The engine controller 15 calculates a rotational speed NE and a load Tq of the engine 1 based on these input signals in a control circuit 151, and also issues a command for the motors 14 a and 14 b according to the calculated NE and Tq from the drive circuit 152. Output a signal.
[0019]
FIG. 3 is a conceptual diagram of gas flow control by the tumble flow control device 11 according to the present embodiment. The gas flow control will be described together with the operation of the engine controller 15 with reference to FIG.
In the present embodiment, the drive mode map of the control valves 13a and 13b shown in FIG. 4 is stored in the control circuit 151 of the engine controller 15. The engine controller 15 determines which of the areas A to D on the map the current operation state determined by the rotation speed NE and the load Tq of the engine 1 is, and selects a drive mode corresponding to the area. .
[0020]
When the engine controller 15 determines that the operating state of the engine 1 is in the low rotation / low load range A, the engine controller 15 selects the first mode as the drive mode. When the first mode is selected, the engine controller 15 outputs a command signal to the motors 14a and 14b to keep both the upstream control valve 13a and the downstream control valve 13b fully closed. Thereby, as shown in FIG. 3A, both the control valves 13a and 13b are closed, and the intake passage is narrowed to the upper passage c1 of the flat plate 12. In this state, the flow of the air facing the upstream control valve 13a is rapidly changed toward the upper wall of the port portion before the control valve 13a, and largely separates when passing through the control valve 13a. For this reason, the substantial flow path of the air is further narrowed, and even at the time of low rotation, the flow rate of the air into the cylinder is increased, and a sufficiently strong tumble flow can be formed.
[0021]
When the engine controller 15 determines that the operating state of the engine 1 is in the region B including the low rotation medium load region, the medium rotation low and medium load region, the high rotation low and the medium load region, the engine controller 15 sets the second mode as the drive mode. select. When the second mode is selected, the engine controller 15 outputs a command signal to the motors 14a and 14b to open the upstream control valve 13a while keeping the downstream control valve 13b fully closed. Thus, as shown in FIG. 3B, the upstream control valve 13a is opened while the lower passage c2 of the flat plate 12 is blocked by the downstream control valve 13b. In this state, the air whose direction has been changed upward before the upstream control valve 13a smoothly flows into the upper passage c1, and the flow separation when passing through the control valve 13a is reduced. Therefore, the air flows along substantially the entire upper passage c1 along the flat plate 12, and the flow passage is substantially enlarged as compared with the case of the first mode. Therefore, at low rotation speed, the amount of intake air can be increased while maintaining the strength of the tumble flow, and at high rotation speed, air can flow smoothly.
[0022]
When the engine controller 15 determines that the operating state of the engine 1 is in the low and middle rotation high load range C, the engine controller 15 selects the third mode as the drive mode. When the third mode is selected, the engine controller 15 outputs a command signal to the motors 14a and 14b to open the downstream control valve 13b while keeping the upstream control valve 13a fully open. Thereby, as shown in FIG. 3C, the passages c1 and c2 are opened both above and below the flat plate 12, and air flows through these passages c1 and c2. Since the air also flows through the lower passage c2, the intake air amount can be further increased with the increase in the load Tq. Here, the air that has passed through the lower passage c2 forms a tumble flow component in the reverse flow direction in the cylinder, but the downstream control valve 13b is not completely opened, and the air is passed through the upper passage than the lower passage. Since c1 flows positively, a tumble flow having a strength necessary for stable combustion can be formed. Then, the downstream control valve 13b is further opened in accordance with the increase in the rotational speed NE, and the ratio of the air flowing through the lower passage c2 to the whole is increased. As the ratio increases, the strength of the tumble flow component in the reverse flow direction increases. However, the increase in the rotation speed NE sufficiently increases the air inflow speed, so that the strength of the tumble flow as a whole can be maintained. .
[0023]
When the engine controller 15 determines that the operation state of the engine 1 is in the high rotation and high load range D, the engine controller 15 selects the fourth mode as the drive mode. When the fourth mode is selected, the engine controller 15 outputs a command signal to the motors 14a and 14b to keep both the upstream control valve 13a and the downstream control valve 13b fully open. Thereby, as shown in FIG. 3D, each of the control valves 13a and 13b is opened, and the air flows through the upper and lower passages c1 and c2 of the flat plate 12. For this reason, the intake air amount can be increased to the maximum.
[0024]
As described above, in the present embodiment, the lower passage c2 of the flat plate 12, which vertically partitions the intake passage, is opened and closed by the two control valves 13a and 13b, and both the control valves 13a and 13b are closed. When opening from the closed state, after opening the upstream control valve 13a, the downstream control valve 13b is opened. Here, the rotation direction of each of the control valves 13a and 13b is set to a direction in which they relatively separate when the valves are opened. For this reason, when the upstream control valve 13a is opened, the lower passage c2 is kept shut off by the downstream control valve 13b, and the upstream control valve 13a hardly receives the force from the intake negative pressure. The torque required to open the control valve 13a needs to be large enough to exceed the pressure caused by the flow of air. Therefore, a relatively small motor 14a can be used. On the other hand, when the downstream control valve 13b is opened, the above-described intake negative pressure and pressure act in a direction in which the control valve 13b opens, so that the torque required for the motor 14b can be very small.
[0025]
Then, in order to close each of the control valves 13a and 13b from the open state, it is preferable to close the downstream control valve 13b and then close the upstream control valve 13a. This prevents a negative pressure from remaining in the space between the control valves 13a and 13b when both control valves 13a and 13b are closed, and the remaining negative pressure when the upstream control valve 13a is opened next time. The required torque can be prevented from increasing due to the pressure.
[0026]
Further, in the present embodiment, the drive mode of the control valves 13a and 13b is switched according to the operation state, and as this drive mode, the opening of the upstream control valve 13a is changed while the downstream control valve 13b is kept fully closed. A second mode in which the opening degree of the downstream control valve 13b is changed while the upstream control valve 13a is fully opened is provided. For this reason, the amount of intake air can be increased while forming a tumble flow having a strength necessary for stable combustion.
[0027]
FIG. 5 shows a general tumble flow control device 101 for a direct-injection gasoline engine, comprising a partition plate 112 and a control valve 113 for opening and closing a passage c2 below the partition plate 112. In this device 101, since the lower passage c2 is opened and closed by one control valve 113, when the control valve 113 is opened according to the increase of the load despite the low rotation, the air also flows to the lower passage c2. The flow and the inflow speed of the air into the cylinder decrease rapidly. Then, since the air that has passed through the lower passage c2 forms a tumble flow component in the reverse flow direction in the cylinder, the tumble flow as a whole is further weakened.
[0028]
In the present embodiment, at the time of low rotation, by selecting the second mode in a region where the load is relatively low, the lower passage c2 is shut off by the downstream control valve 13b to narrow the intake passage, and the tumble flow is reduced. , The amount of air flowing through the upper passage c1 can be increased. Further, when it is necessary to further increase the intake air amount in response to the increase in the load, it is possible to cope with this by switching to the third mode. By such fine control, it is possible to cause the engine 1 to suck in a necessary amount of air while forming a tumble flow having a strength necessary for stable combustion.
[Brief description of the drawings]
FIG. 1 is a sectional view of a direct injection gasoline engine according to an embodiment of the present invention; FIG. 2 is a configuration diagram of a tumble flow control device according to the embodiment; FIG. 3 is a concept of gas flow control by the tumble flow control device; Fig. 4 Drive mode map of control valve Fig. 5 Conceptual diagram of gas flow control by general tumble flow control device of direct injection gasoline engine [Explanation of reference numerals]
DESCRIPTION OF SYMBOLS 1 ... Engine, 4 ... Intake system port part, 5 ... Exhaust system port part, 11 ... Tumble flow control device as intake flow control device, 12 ... Flat plate as partition plate, 13a ... Upstream as first valve Side control valve, 13b: downstream control valve as second valve, 14a, 14b: motor as drive means, 15: engine controller, c1: upper passage, c2: lower passage.

Claims (7)

A partition plate that divides an intake passage, which is installed along a flow of air in a port portion of the intake system,
A valve for opening and closing the one-side passage, which is installed in the one-side passage partitioned by the partition plate,
Driving means for driving the valve to open and close the one-side passage,
The valve includes a butterfly-type first valve, and a butterfly-type second valve installed downstream of the first valve.
An intake flow control device for an internal combustion engine, wherein the driving means rotates the first and second valves in directions opposite to each other. 2. The intake flow control device for an internal combustion engine according to claim 1, wherein the partition plate partitions an intake passage into upper and lower portions, and the first and second valves are installed in a lower passage partitioned by the partition plate. 3. . 3. The intake flow control device for an internal combustion engine according to claim 1, wherein the drive unit rotates the first and second valves in a direction in which the first and second valves are separated from each other when the valves are opened. 4. The intake air flow of an internal combustion engine according to claim 3, wherein the drive unit opens the first valve and then opens the second valve when opening the first and second valves from a state where both are closed. Control device. 5. The intake air flow of an internal combustion engine according to claim 4, wherein the drive means closes the first valve after closing the second valve when the drive means closes both the first and second valves from an open state. Control device. The drive means includes, as drive modes of the first and second valves, a first mode in which these valves are both kept closed, and an opening degree of the first valve in a state in which the second valve is closed. A second mode in which the opening degree of the second valve is changed while the first valve is open, and a fourth mode in which both the first and second valves are kept open. 4. The intake flow control device for an internal combustion engine according to claim 3, comprising: 7. The internal combustion engine according to claim 6, wherein the driving unit drives the first and second valves in the order of the first, second, third, and fourth modes in accordance with an increase in engine load. Intake flow control device.

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