JP2009216024A - Intake device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intake device of an internal combustion engine capable of properly changing a cross sectional area of an intake passage, eliminating the risk of a sudden flow of gas from the inside of the intake passage into a cylinder. <P>SOLUTION: An expandable/shrinkable bag 3 as a flow passage changing member, a pump 5 for supplying compressed air into the bag 3, and a pressure control valve 4 for changing the pressure inside the bag 3 are provided in an intake device 1 so that a cross sectional area of a flow passage 2b of an intake port 2 is changed in the state of fixing to one part 2a of the inner wall surface of the intake port 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an intake device for an internal combustion engine capable of changing a cross-sectional area of an intake passage.

  A movable member such as a movable plate or a partition plate is provided in the intake passage of the internal combustion engine, and a specific intake flow such as a tumble flow is generated in the cylinder by driving the movable member to change the cross-sectional area of the intake passage. There is known an intake device that can switch between a state and a state in which a ventilation resistance by a movable member is reduced to correspond to an increase in intake air amount (see, for example, Patent Documents 1 and 2). In addition, there is Patent Document 3 as a prior art document related to the present invention.

JP-A-8-121178 JP 2004-11442 A JP 2005-180247 A

  In the internal combustion engine having the above-described intake device, the fuel injected into the port from the fuel injection valve by the asynchronous injection control at the cold start flows into the bag-like inner space of the movable member, and the fuel stays until the warm-up is completed. There are things to do. In this case, after the warm-up is completed, when the movable member is driven to increase the cross-sectional area, the fuel remaining in the internal space of the movable member suddenly flows into the cylinder. In the case of an internal combustion engine that introduces EGR gas into the intake passage in a wide range of operation, high-concentration EGR gas may temporarily remain in the internal space of the movable member during transient operation. Also in this case, when the movable member is driven to increase the cross-sectional area, the EGR gas remaining in the internal space of the movable member suddenly flows into the cylinder. Since it is difficult to predict the residual amount of gases in the movable member (here, gases that affect combustion, including fuel spray, EGR gas, etc.), the air-fuel ratio control is disturbed by the rapid inflow. Inconvenience may occur.

  Therefore, the present invention provides an intake device for an internal combustion engine capable of appropriately changing the cross-sectional area of the intake passage while eliminating the possibility that gases in the intake passage suddenly flow into the cylinder. Objective.

  An intake device for an internal combustion engine according to the present invention is a bag-like flow path change that can be expanded and contracted so that the flow path cross-sectional area of the intake path changes while being fixed to a part of the inner wall surface of the intake path. A fluid supply means for supplying a fluid to the inside of the flow path changing member; and a pressure adjusting means for changing the pressure inside the flow path changing member.

  In the intake device of the present invention, the flow passage cross-sectional area in the intake passage can be changed by expanding or contracting the flow passage changing member. The internal space of the bag-shaped flow path changing member is completely partitioned from the area where the intake air in the intake passage flows, and no bag-like space is formed in the intake passage, so fuel, EGR gas, etc. are introduced into the intake passage. However, they do not remain in the internal space of the flow path changing member, and each time the intake valve is opened, those gases are pushed out into the intake air and flow into the cylinder. Therefore, there is no possibility that gases such as fuel or EGR gas are accumulated in the intake passage and the gases suddenly flow into the cylinder when the flow passage cross-sectional area increases. By contracting the flow path changing member, it is possible to sufficiently reduce the resistance that the flow path changing member gives to the flow of intake air and easily cope with an increase in the intake air amount.

  In one aspect of the present invention, when the flow path changing member expands, the downstream end of the flow path changing member in the intake flow direction may be located at a position facing the terminal end of the intake passage. Item 2). According to this aspect, by expanding the flow path changing member, the flow path can be narrowed to the vicinity of the end portion of the intake passage, and a specific intake flow can be reliably generated in the cylinder.

  In one embodiment of the present invention, the apparatus may further include a pressure control unit that controls an operation of the pressure adjusting unit so that a pressure inside the flow path changing member changes according to a required air amount of the internal combustion engine. Claim 3). According to this embodiment, the flow path changing member expands or contracts according to the required air amount, and the flow path cross-sectional area changes. Thereby, a flow-path cross-sectional area can be optimized with respect to the load of an internal combustion engine.

  In one form of the intake device of the present invention, a fuel injection valve that injects fuel toward the end portion of the intake passage may be provided in a region that is not blocked by the flow path changing member of the intake passage. Good (Claim 4). Alternatively, the end portion of the EGR pipe for introducing EGR gas may be connected to a region of the intake passage that is not blocked by the flow path changing member (Claim 5). According to these embodiments, even if fuel or EGR gas is introduced into the intake passage, each time the intake valve is opened, these gases can be introduced into the cylinder without remaining in the intake passage.

  As described above, in the intake device for an internal combustion engine according to the present invention, the flow passage changing member fixed to a part of the inner wall surface of the intake passage is expanded or contracted, thereby reducing the flow passage cross-sectional area of the intake passage. It is possible to change appropriately. Each time the intake valve opens, the gases in the intake passage can flow into the cylinder, eliminating the risk of these gases suddenly flowing into the cylinder when the flow path cross-sectional area increases. Can do. Moreover, when the flow path changing member is contracted, it is possible to sufficiently reduce the resistance that the flow path changing member gives to the flow of intake air, and it is possible to easily cope with an increase in the intake air amount.

  FIG. 1 is a longitudinal sectional view showing a main part of an intake system of an internal combustion engine to which an intake device according to an embodiment of the present invention is applied. FIG. 1 is drawn with the cylinder axis of the internal combustion engine oriented in the vertical direction and the cylinder head positioned above the combustion chamber. In the illustrated intake apparatus 1, a bag 3 as a bag-shaped flow path changing member capable of expansion and contraction is provided inside an intake port 2 which is a part of an intake passage of an internal combustion engine. FIG. 1 shows a state where the bag 3 is inflated. The bag 3 has a shape extending in the intake air flow direction in the intake port 2, and at least a part of the lower surface 3 a is fixed to the lower surface 2 a that is a part of the inner wall surface of the intake port 2. The bag 3 is sized so as to fill a substantially lower half space of the intake port 2 in the inflated state and leave the intake flow path 2b on the upper surface 3b side.

  An intake / exhaust port 3 c is provided at the center of the lower surface 3 a of the bag 3. The intake / exhaust port 3 c is drawn out of the intake port 2, and a pump 5 is connected to a tip portion of the intake / exhaust port 3 c via a pressure regulating valve 4. The pressure regulating valve 4 sends the fluid supplied from the pump 5 into the bag 3 or discharges the fluid from the bag 3 to adjust the pressure inside the bag 3. Thereby, it functions as a pressure adjusting means of the present invention. The pump 5 functions as a fluid supply means of the present invention by sending a high-pressure fluid (here, compressed air as an example) to the pressure regulating valve 4. The pump 5 may be operated by taking in power from rotating parts such as a crankshaft and an axle of the internal combustion engine, or may be operated using a power source of a vehicle on which the internal combustion engine is mounted. A tank capable of accumulating pressure may be provided between the pump 5 and the pressure regulating valve 4.

  A valve shaft 6a of the intake valve 6 is passed through the end portion (corresponding to the end portion of the intake passage) 2d of the intake port 2. In the inflated state, the bag 3 has an end portion at a position where the downstream end of the intake port 2 in the intake flow direction is somewhat retracted from the valve shaft 6a to the upstream in the intake flow direction (right side in FIG. 1). It is provided to face 2d. Although the intake port 2 is provided inside the cylinder head, a part of the bag 3 shown in FIG. 1 may be located in the branch pipe of the intake manifold. Further, although the internal combustion engine is provided with a plurality of intake ports according to the number of cylinders, an intake device having the same configuration as in FIG. 1 is applied to other intake ports.

  A fuel injection valve 8 for port injection is provided in the flow path 2 b above the intake port 2, that is, in a region that is not blocked by the bag 3. The fuel injection valve 8 injects fuel toward the end portion 7 of the intake port 2. The end portion 9 a of the EGR pipe 9 is further connected to the flow path 2 b of the intake port 2. EGR gas returned from the exhaust passage of the internal combustion engine is introduced into the flow path 2b from the EGR pipe 9 via the EGR delivery 10.

  The operations of the pressure regulating valve 4 and the pump 5 are controlled by an engine control unit (hereinafter referred to as ECU) 20. The ECU 20 is a computer unit that controls the internal combustion engine to a target operating state by controlling the fuel injection amount from the fuel injection valve 8 based on information such as the engine speed and load of the internal combustion engine. Control of the pressure regulating valve 4 and the like by the ECU 20 will be described later.

  Next, the operation of the intake device 1 will be described with reference to FIGS. FIG. 2 shows the behavior of the fuel when the fuel 30 is injected asynchronously from the fuel injection valve 8 into the intake port 2 with the bag 3 inflated during a cold start of the internal combustion engine. The fuel injected asynchronously diffuses in the vicinity of the end portion 2d of the intake port 2 until the intake valve 6 is opened. As shown in FIG. 3, when the EGR gas 31 is introduced from the EGR pipe 9 into the flow path 2 b with the bag 3 inflated and the intake valve 6 closed, the EGR gas 31 is introduced into the intake valve 6. Diffuses in the vicinity of the end portion 2d of the intake port 2 until is opened.

  On the other hand, when the intake valve 6 is opened as shown in FIG. 4, the intake air A is introduced into the cylinder 13 via the flow path 2b. At this time, the fuel 30 and the EGR gas 31 remaining in the end portion 2d of the intake port 2 are pushed out into the intake air A and flow into the cylinder 13. In the state of FIG. 4, since the lower half space of the intake port 2 is filled with the bag 3, the intake air A flows in a direction biased toward the center of the cylinder 13, thereby relatively strong tumble in the cylinder 13. A flow is formed. Further, by adjusting the internal pressure of the bag 3 to change the cross-sectional area of the flow path 2b, the intake air amount (intake amount) can be continuously changed. For example, the intake amount can be increased by contracting the bag 3 as shown by the broken line in FIG. When the bag 3 is almost completely folded, the resistance that the bag 3 gives to the flow of intake air is sufficiently small, and it is easier to increase the intake amount than in the conventional example in which the partition plate or the like remains in the intake port 2. Can respond.

  According to the configuration described above, even when the bag 3 is inflated to reduce the cross-sectional area of the flow path 2 b, a bag path-like space like the internal space of the conventional movable member does not occur inside the intake port 2. For this reason, it is possible to eliminate the possibility that the fuel 30 and the EGR gas 31 remain in the intake port 2 even though the intake valve 6 is opened. That is, every time the intake valve 6 is opened, the fuel 30 and the EGR gas 31 in the intake port 2 almost completely flow into the cylinder 13. For this reason, residual gas is accumulated in the intake port 2, and when the bag 3 is folded to increase the cross-sectional area of the flow path 2b, the residual gas suddenly flows into the cylinder 13 and the air-fuel ratio control is disturbed. It is possible to eliminate the possibility of such inconvenience.

  Next, a procedure for adjusting the pressure of the bag 3 by the ECU 20 will be described. The ECU 20 executes various routines for controlling the operating state of the internal combustion engine. As one of them, the ECU 20 repeatedly executes the flow path cross-sectional area control routine of FIG. 5 at a predetermined cycle. The flow path cross-sectional area control routine is a process for controlling the cross-sectional area of the flow path 2b of the intake port 2 in accordance with the operating state of the internal combustion engine. When the flow path cross-sectional area control routine of FIG. 5 is started, the ECU 20 first determines the operating state of the internal combustion engine in step S1. The operating state may be determined based on information such as the engine speed and the opening degree of the accelerator pedal, similarly to the control of the known internal combustion engine. In the subsequent step S2, the ECU 20 calculates a required air amount corresponding to the operating state, that is, an intake air amount necessary for controlling the internal combustion engine to the target operating state. The calculation method may be performed in the same manner as the operation control of a known internal combustion engine. In the next step S3, the ECU 20 determines a target pressure in the bag 3 corresponding to the required air amount. In this case, the target pressure of the bag 3 decreases as the required air amount increases. In order to execute the process of step S3, a map that associates the relationship between the required air amount and the pressure in the bag 3 is created in advance by a bench fit test or the like, stored in the ROM of the ECU 20, and the map is stored. The pressure corresponding to the required air amount may be acquired as a target pressure by referring to it. If the influence of the intake pressure on the expansion rate of the bag 3 cannot be ignored, the target pressure may be determined in consideration of the intake pressure in step S3. For example, the target pressure may be corrected to a relatively small value as the intake pressure is lower.

  In subsequent step S4, the ECU 20 changes the set value of the pressure regulating valve 4 so that the pressure of the bag 3 becomes the target pressure determined in step S3. In this case, if the set value of the pressure regulating valve 4 before the control is a value higher than the target pressure, the set value of the pressure regulating valve 4 may be lowered to discharge air from the bag 3. On the other hand, when the set value of the pressure regulating valve 4 before the control is lower than the target pressure, it is necessary to raise the set value of the pressure regulating valve 4 and drive the pump 5 to send air into the bag 3. After adjusting the pressure in step S4, the ECU 20 ends the current routine. By executing the above routine, the ECU 20 functions as pressure control means.

  FIG. 6 is a graph showing the relationship between the required air amount of the internal combustion engine and the tumble ratio. The solid line in the figure shows the case of the intake device 1 of the present embodiment, and the broken line in the figure shows the conventional intake port 2 in the intake port 2. This shows a case of an intake device having a fixed partition plate. As is apparent from FIG. 6, in this embodiment, as the required air amount increases, the pressure of the bag 3 is controlled to be small, the intake air amount increases, and the tumble ratio increases as the intake air amount increases. Although the relationship is the same in the conventional example, as the required air amount increases, the partition plate in the intake port becomes a resistance, and the air amount reaches a peak earlier than in this embodiment. As a result, the upper limit of the tumble ratio is also small in the conventional example. On the other hand, according to the intake device 1 of the present embodiment, the air resistance when the bag 3 is contracted is smaller than that of the conventional example, so that the upper limit of the required air amount is expanded, and the upper limit of the tumble ratio is also compared with that of the conventional example. And get bigger.

  This invention is not limited to the form mentioned above, It can implement with a various form. For example, in the above embodiment, the lower half area of the intake port 2 is filled with the bag 3 for the purpose of forming a tumble flow. However, the bag 3 is arranged in either the left or right space of the intake port to provide a swirl flow. May be controlled. The fluid supplied to the inside of the bag 3 is not limited to air but may be a fluid such as water.

The longitudinal section showing the important section of the intake system to which the intake device concerning one form of the present invention was applied. The figure which shows the behavior of the fuel injected asynchronously in the intake port from the fuel injection valve. The figure which shows the behavior of EGR gas introduce | transduced in the intake port. The figure which shows the flow of intake air when an intake valve opens from the state of FIG. 2 or FIG. The flowchart which shows the flow-path cross-sectional area control routine which ECU of FIG. 1 performs. The figure which shows the relationship between the request | requirement air amount of an internal combustion engine, and a tumble ratio.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Intake device 2 Intake port 2b Flow path in intake port 2d Terminal part of intake port 3 Bag (flow path changing member)
4 Pressure regulating valve (pressure adjusting means)
5 Pump (fluid supply means)
6 Intake valve 8 Fuel injection valve 9 EGR pipe 10 EGR delivery 13 Cylinder 20 Engine control unit (pressure control means)
30 Fuel 31 EGR gas

Claims (5)

  A bag-like flow path changing member that can be expanded and contracted so that the flow passage cross-sectional area of the intake passage changes while being fixed to a part of the inner wall surface of the intake passage, and inside the flow path changing member An intake device for an internal combustion engine, comprising: a fluid supply means for supplying fluid; and a pressure adjusting means for changing the pressure inside the flow path changing member.   2. The intake device according to claim 1, wherein when the flow path changing member expands, the downstream end of the flow path changing member in the intake flow direction faces the terminal end of the intake passage.   The intake device according to claim 1, further comprising a pressure control unit that controls an operation of the pressure adjusting unit so that a pressure inside the flow path changing member changes according to a required air amount of the internal combustion engine. .   The fuel injection valve for injecting fuel toward the end portion of the intake passage is provided in a region that is not blocked by the flow path changing member of the intake passage. The inhaler described.   The intake device according to any one of claims 1 to 4, wherein an end portion of an EGR pipe for introducing EGR gas is connected to a region of the intake passage that is not blocked by the flow path changing member.

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