JP2010236478A - Fuel injection-intake device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To expand an operation area in which atomization of injected fuel is appropriately performed, improve combustion efficiency over a wide operation area, and reduce unburned components in exhaust gas. <P>SOLUTION: Under quantitative control of an air flow rate by a sub throttle valve 90, air matching a requested air quantity is supplied to a sub intake supply port 75 not only during an idle operation but from an idle operation over an operation region in which the requested air quantity is less than a prescribed value, and when the operation area becomes one in which the requested air quantity is the prescribed value or more, a state in which the sub throttle valve 90 is opened is maintained, and an air quantity equivalent to the prescribed value is supplied to the sub intake supply port 75. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fuel injection / intake apparatus for an internal combustion engine, and more particularly to a fuel injection / intake apparatus for an internal combustion engine having a sub-intake system for idling to low load operation.

  As an intake device for an internal combustion engine, there is known an intake device that is provided with a bypass intake passage that bypasses a throttle valve and supplies intake air to an intake passage downstream of the throttle valve by the bypass intake passage (for example, Patent Document 1). ).

  In an intake device with a bypass intake passage, the idling speed is controlled by measuring the flow rate of intake air flowing through the bypass intake passage with a flow rate control valve called an idle speed control valve while the throttle valve is closed. (For example, Patent Document 2).

  In a fuel-injection internal combustion engine, intake air flowing through the bypass intake passage is used as assist air, which is jetted toward the jet of fuel injected from the fuel injection valve to atomize the injected fuel and reduce the fuel adhering to the wall (For example, Patent Document 3).

No. 2-7365 JP 2007-32426 A Japanese Patent Laid-Open No. 4-50469

  During idle operation when the throttle valve (main throttle valve) is closed, the throttle valve (main throttle valve) is closed and the air flowing through the bypass intake passage secures the amount of air required for idle operation. We can expect atomization of injected fuel by air.

  However, during load operation with the throttle valve opened, the amount of air required for load operation is secured exclusively by the air flowing through the intake passage (main intake passage) where the throttle valve is provided, and there is less air flowing through the bypass intake passage. Therefore, a sufficient assist air flow rate cannot be secured, and the atomized fuel is not sufficiently atomized. If the atomization of the injected fuel is not sufficiently performed, the combustion efficiency is lowered and the unburned components in the exhaust gas are increased.

  The problem to be solved by the present invention is to expand the operating range in which atomization of the injected fuel is appropriately performed, improve the combustion efficiency over a wide operating range, and reduce unburned components in the exhaust gas. It is.

  A fuel injection-intake device for an internal combustion engine according to the present invention includes a main intake passage communicating with a combustion chamber of the internal combustion engine, and a main throttle valve that quantitatively controls the flow rate of air flowing through the main intake passage according to the valve opening amount. A fuel injection valve that injects fuel into the main intake passage on the intake downstream side of the main throttle valve, and a direction that collides with a spray bundle of fuel injected from the fuel injection valve on the intake downstream side of the main throttle valve A sub-intake supply port for supplying air to the sub-intake, a sub-throttle valve for quantitatively controlling the flow rate of air supplied to the sub-intake supply port according to the valve opening amount, and a required air amount according to the operating state of the internal combustion engine Required air amount calculating means for calculating the required air amount, and in the operating range where the required air amount calculated by the required air amount calculating means is less than a predetermined value, the main throttle valve is fully closed and the amount of Only the valve opening amount of the auxiliary throttle valve is controlled, and in the operating range where the required air amount is a predetermined value or more, the auxiliary throttle valve is kept open and the main throttle valve is opened according to the required air amount. Throttle valve control means for controlling the amount.

  According to this configuration, the auxiliary intake supply port has an operating range in which the required air amount from the idle operation is less than the predetermined value, not only during the idle operation, under the quantitative control of the air flow rate by the auxiliary throttle valve. Even when the air corresponding to the required air amount is supplied over the operating range where the required air amount is equal to or greater than the predetermined value, the sub throttle valve is kept open and continues to the sub intake air supply port. Since the air corresponding to the value is supplied, the atomization of the injected fuel by the air from the auxiliary intake supply port is appropriately performed over a wide operation range.

  In the fuel injection-intake apparatus for an internal combustion engine according to the present invention, preferably, the main intake passage is provided for each of a plurality of cylinders constituting the combustion chamber, and the main throttle valve is provided for each of the main intake passages. ing.

  According to this configuration, the length of the intake passage from the main throttle valve to each cylinder (combustion chamber) can be set short, and the response of changes in the actual intake air amount due to changes in the throttle opening is improved. In addition, since the intake passage volume downstream of the main throttle valve is smaller than the main throttle valve, a strong intake negative pressure atmosphere is generated downstream of the main throttle valve, and the air injection speed from the auxiliary intake supply port is increased. The speed is increased and atomization of the injected fuel is favorably performed.

  The fuel injection / intake device for an internal combustion engine according to the present invention is preferably formed with the main intake passage and an injection valve insertion hole which is communicated with the main intake passage and into which the tip of the fuel injection valve is inserted and mounted. An injection valve mounting member is provided, the fuel injection port of the fuel injection valve is disposed in the injection valve insertion hole, and the auxiliary intake air supply port is opened in the injection valve insertion hole.

  According to this configuration, since the auxiliary intake supply port does not open directly to the wall surface of the main intake passage, the auxiliary intake supply port does not disturb the flow of air flowing through the main intake passage, and the intake efficiency is not reduced. .

  The fuel injection-intake apparatus for an internal combustion engine according to the present invention is preferably a cylindrical injection hole in which a spray diffusion chamber for fuel injected from the fuel injection port of the fuel injection valve is formed in the injection valve insertion hole. An adapter is attached, and the auxiliary intake supply port is formed in a peripheral wall that defines the spray diffusion chamber.

  According to this configuration, since the sub-intake supply port is formed in the injection hole adapter, an optimum sub-intake supply port can be simply realized by only changing the injection hole adapter without changing the injection valve mounting member. be able to.

  In the fuel injection-intake apparatus for an internal combustion engine according to the present invention, preferably, two intake ports are formed for each cylinder, and the main intake passage communicates with the two intake ports for each cylinder. Two auxiliary intake supply ports are formed on a virtual plane orthogonal to the arrangement direction of the two intake ports so as to face each other.

  According to this structure, the degree to which the fuel spray foam is sprayed to the partition wall between the two intake ports due to the spray of air from the auxiliary intake supply port deforms the fuel spray foam into a bowl shape matching the arrangement of the two intake ports. This reduces the amount of fuel adhering to the partition walls.

  According to the fuel injection-intake apparatus for an internal combustion engine according to the present invention, good atomization of the injected fuel by the air from the auxiliary intake supply port can be appropriately performed over a wide operating range without being limited to the idling operation. Thus, combustion efficiency is improved over a wide operating range, and unburned components in the exhaust gas can be reduced over a wide operating range.

1 is a configuration diagram showing one embodiment of a fuel injection type V-type internal combustion engine to which a fuel injection-intake device according to the present invention is applied. The figure which shows typically the fuel-injection-intake apparatus by this embodiment. FIG. 3 is an enlarged longitudinal sectional view of a main part of the fuel injection-intake device according to the present embodiment. The plane sectional view of the important section in the fuel injection-intake device by this embodiment. The plane sectional view showing an air intake device. The graph which shows the throttle valve opening characteristic of the fuel injection-intake apparatus by this embodiment.

  Hereinafter, an embodiment of a fuel injection-intake device for an internal combustion engine according to the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the internal combustion engine (engine) of the present embodiment is a V-type multi-cylinder engine, and a cylinder bore 16 is formed in each of the right bank portion 12 and the left bank portion 14 of the cylinder block 10. ing. A plurality of cylinder bores 16 are provided in a direction orthogonal to the plane of FIG. 1. In the case of a 10-cylinder V-type engine, five cylinder bores 16 are formed by the right bank portion 12 and the left bank portion 14, respectively.

  A cylinder head 18 is attached to each of the right bank portion 12 and the left bank portion 14 of the cylinder block 10 so as to close the upper end of the cylinder bore 16. A piston 20 is provided in the cylinder bore 16 so as to be able to reciprocate. The piston 20 defines a combustion chamber 22 (# 1 to # 5 cylinder) with the cylinder head 18.

  The cylinder head 18 of each bank has an intake port 24 and an exhaust port 26 for each combustion chamber 22. The intake port 24 and the exhaust port 26 are opened and closed at the open end (downstream end) with respect to the combustion chamber 22 by an intake valve 28 and an exhaust valve 30, respectively. As shown in FIG. 4, the intake port 24 is of the twin-import type and has a bifurcated passage structure in which two intake ports 24A and 24B are formed for each combustion chamber 22 of each cylinder.

  An injector base member 40, which is an injection valve mounting member, is attached to the intake connection surface portion (surface portion where the upstream end of the intake port 24 is opened) of the cylinder head 18 of each bank. As shown in FIG. 2, the injector base member 40 is formed with a plurality of main intake passages 42 that individually communicate with the intake ports 24 of the respective cylinders. That is, the main intake passage 42 is individually formed in the injector base member 40 for each of a plurality of cylinders that constitute the combustion chamber 22. A fuel injection valve 60 is attached to the injector base member 40 for each main intake passage 42. The mounting structure of the fuel injection valve 60 will be described later in detail.

  A throttle body 80 is attached to the intake upstream side of the injector base member 40. The throttle body 80 has a plurality of throttle passages 82 that individually communicate with the main intake passages 42. The throttle passage 82 is individually provided for each cylinder. A main throttle valve 84 is provided in each of the plurality of throttle passages 82. The main throttle valve 84 is a multiple type provided individually for each cylinder, that is, for each main intake passage 42, and is a butterfly valve that is rotatably supported by the throttle body 80 by a common valve shaft 86. It is. The main throttle valves 84 of the cylinders are simultaneously opened and closed by a valve shaft 86, and the flow rate (main intake air amount) of the air sucked into the combustion chambers 22 through the main intake passage 42 according to the valve opening amount is quantitatively determined. Control (weigh).

  An electric motor 88 such as a pulse motor is connected to the valve shaft 86. The electric motor 88 rotates the valve shaft 86 and quantitatively sets the valve opening amount of the main throttle valve 84 according to the rotation angle.

  Such a throttle mechanism is called a cylinder-by-cylinder throttle or a multiple throttle, and in this multiple throttle, the intake passage length from each throttle valve to the combustion chamber of each cylinder can be set short, so that the throttle opening change Responsiveness of actual intake air amount change due to.

  A main intake chamber 85 forming a collecting pipe portion of the intake manifold is connected to the intake upstream side of the throttle body 80.

  As shown in FIG. 3, the injector base member 40 has a circular transverse cross-section injection valve insertion hole 44 communicating with the main intake passage 42 on the intake downstream side of the main throttle valve 84 for each main intake passage 42. Is formed. The tip of the fuel injection valve 60 is inserted into the injection valve insertion hole 44. The fuel injection valve 60 has an injection hole member 63 having a fuel injection port 61 and a valve seat portion 62 at the tip. A valve body 64 is provided in the injection hole member 63. The valve body 64 is electromagnetically driven in the axial direction, so that the valve body 64 is selectively seated and separated from the valve seat portion 62 to open and close the fuel injection port 61.

  An orifice plate 72 is disposed on the tip surface of the injection hole member 63. In the orifice plate 72, two orifice holes 73 are formed at a small interval in the same direction as the arrangement direction of the two intake ports 28A, 28B (see FIG. 4). Thereby, the fuel ejected from the fuel injection port 61 is divided into two spray bundles F by the two orifice holes 73 and becomes spray bundles directed to the intake ports 28A and 28B, respectively.

  A single orifice hole 73 is formed in the orifice plate 72, one spray bundle is formed by the orifice hole 73, and the above one spray bundle is formed by blowing air from two auxiliary intake air supply ports 75 described later. The spray bundle may be divided into two and directed to the two intake ports 28A and 28B.

  A cylindrical injection hole adapter 65 is fixedly attached to the outer periphery of the injection hole member 63. The injection hole adapter 65 is in the injection valve insertion hole 44 together with the tip of the fuel injection valve 60. The injection hole adapter 65 includes an O-ring 69 and a peripheral groove 67 formed by the flange portion 66 at the root end and the main body housing 60 </ b> A of the fuel injection valve 60, and a peripheral groove 68 formed on the outer periphery of the tip end portion of the injection hole adapter 65. 70 is attached. The O-rings 69 and 70 are pressed against the inner peripheral surface of the injection valve insertion hole 44, and the O-rings 69 and 70 are circular between the inner peripheral surface of the injection valve insertion hole 44 between the O-rings 69 and 70 and the outer peripheral surface of the injection hole adapter 65. An annular space 71 is defined.

  The injection hole adapter 65 has a funnel-shaped spray diffusion chamber 74 formed in front of the fuel injection port 61 of the fuel injection valve 60. The fuel injected from the fuel injection port 61 and passing through the orifice hole 73 is sprayed and diffused in the spray diffusion chamber 74 and is jetted from the spray diffusion chamber 74 toward the intake port 24.

  A sub-intake supply port 75 is formed in the circumferential wall 74 </ b> A in which the nozzle hole adapter 65 defines the spray diffusion chamber 74. Two auxiliary intake supply ports 75 are formed opposite to each other on a virtual plane (paper surface in FIG. 3) orthogonal to the arrangement direction of the two intake ports 28A, 28B. The spray diffusion chamber 74 is opened into the spray diffusion chamber 74 in a form inclined toward the tip opening side of the spray diffusion chamber 74 with an inclination angle of about 30 degrees with respect to the central axis of the diffusion chamber 74.

  Thus, the auxiliary intake air supply port 75 supplies air in a direction in which it collides with the fuel spray bundle F injected from the fuel injection valve 60 on the intake downstream side of the main throttle valve 84.

  When the air (air flow A) from the auxiliary intake air supply port 75 collides with the fuel spray bundle F, atomization of the fuel is promoted. Further, the two auxiliary intake air supply ports 75 are formed opposite to each other on a virtual plane (paper surface in FIG. 3) orthogonal to the arrangement direction of the two intake air ports 28A and 28B. The fuel spray foam is deformed into a saddle shape matching the arrangement of the two intake ports 24A and 24B by blowing air to sandwich the fuel spray bundle from 75. Thereby, the degree to which fuel spray is sprayed onto the partition wall 28C between the two intake ports 24A, 24B is reduced, and the amount of fuel adhering to the partition wall is reduced. Even when the single orifice hole 73 is formed in the orifice plate 72, the same effect can be obtained by adopting the arrangement of the auxiliary intake air supply port 75 described above.

  The injector base member 40 is formed with a branch passage 45 communicating with an annular space 71 defined in the injection valve insertion hole 44 of each cylinder. The branch passage 45 communicates with the throttle passage 92 of the sub-throttle device via the auxiliary intake chamber 46 and the collecting passage 47 on the intake upstream side.

  The throttle passage 92 is provided with a sub throttle valve 90 using a butterfly valve. The sub-throttle valve 90 quantitatively controls (measures) the flow rate of air flowing through the throttle passage 92 according to the valve opening amount, that is, the air (sub-intake amount) ejected from the sub-intake supply port 75 to the spray diffusion chamber 74. To do. An electric motor 94 such as a pulse motor is drivingly connected to the sub-throttle valve 90. The electric motor 94 rotates the sub throttle valve 90 and quantitatively sets the opening amount of the sub throttle valve 90 according to the rotation angle.

  A throttle control device 100 that controls the electric motor 88 of the main throttle valve 84 and the electric motor 94 of the sub throttle valve 90 is provided. The throttle control device 100 forms part of an engine control unit using a microcomputer, and includes a required air amount calculation unit 102 and a throttle valve control unit 104.

The required air amount calculation unit 102 receives information related to the accelerator pedal depression amount from the accelerator pedal sensor 106 and information related to the engine speed from the engine speed sensor 108.
The required air amount Q is calculated from the accelerator pedal depression amount and the engine speed.

  The throttle valve control unit 104 has a control characteristic as shown in FIG. 5 based on the required air amount Q calculated by the required air amount calculation unit 102 and the control target valve opening degree θsec of the main throttle valve 84 and the sub throttle. A control target valve opening degree θpri of the valve 90 is set, and a control command according to the set target opening degree θpri is output to the electric motors 88 and 94.

  Thereby, the electric motor 88 drives the main throttle valve 84 to the control target valve opening degree θsec, and the electric motor 94 drives the sub throttle valve 90 to the control target valve opening degree pri.

  In the present embodiment, as shown in FIG. 5, the main throttle valve 84 is fully closed (θsec) in the operation range where the required air amount Q is less than the predetermined value Qprimax, that is, in the idling operation to the low load operation range. = 0), only the valve opening amount of the sub-throttle valve 90 is controlled with the control target valve opening degree θpri according to the required air amount Q, and the operating range where the required air amount Q is equal to or greater than a predetermined value Qprimax, that is, the medium load In the high-load operation region, the maximum opening state of the sub throttle valve 90 is maintained, and the opening amount of the main throttle valve 84 is controlled with the control target valve opening degree θsec according to the required air amount Q.

  It should be noted that the valve opening amount of the auxiliary throttle valve 90 during idle operation, that is, the idle opening may be set based on the engine speed of the control target. The predetermined value Qprimax may be variably set to an appropriate value according to the engine speed.

  By the above-described control, the required air amount Q from the idle operation is less than the predetermined value Qprimax in the auxiliary intake air supply port 75 not only during the idle operation but under the quantitative control of the air flow rate by the auxiliary throttle valve 90. Even when the air corresponding to the required air amount Q is supplied over a certain operating range and the required air amount Qprimax is in an operating range where the required air amount Qprimax is equal to or greater than a predetermined value, the sub throttle valve 90 remains open and the secondary sub valve continues. Air corresponding to a predetermined value Qprimax is supplied to the intake air supply port 75.

  As a result, the atomization of the injected fuel by the air from the auxiliary intake air supply port 75 is appropriately performed over a wide operating range, the combustion efficiency is improved over the wide operating range, and the wide operating range is achieved. Reduction of unburned components in the exhaust gas is achieved.

  According to the present embodiment, the main throttle valve 84 is close to the intake port 24, and the intake passage length from the main throttle valve 84 to each cylinder (combustion chamber 22) can be set short. Responsiveness of intake air amount change is improved. In addition, since the intake passage volume on the intake downstream side of the main throttle valve 84 is small, a strong intake negative pressure atmosphere is generated on the intake downstream side of the main throttle valve 84. The ejection speed is increased and the atomization of the injected fuel is favorably performed.

According to the present embodiment, since the auxiliary intake supply port 75 does not open directly to the wall surface of the main intake passage 42, the auxiliary intake supply port 75 does not disturb the flow of air flowing through the main intake passage 42, and the intake efficiency decreases. Is not invited.
In addition, since the sub-intake supply port 75 is formed in the injection hole adapter 65, the optimum sub-intake supply port 75 can be realized simply by changing the injection hole adapter 65 without the need to change the injector base member 40. Can do.

  The fuel injection-intake apparatus according to the present invention is not limited to the above-described embodiments, and can be changed without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 22 Combustion chamber 40 Injector base member 42 Main intake passage 44 Injection valve insertion hole 60 Fuel injection valve 65 Injection hole adapter 74 Spray diffusion chamber 75 Sub intake air supply port 90 Sub throttle valve 102 Rain class air amount calculation part 104 Throttle valve control part

Claims (5)

A main intake passage communicating with the combustion chamber of the internal combustion engine;
A main throttle valve that quantitatively controls the flow rate of air flowing through the main intake passage according to the valve opening amount;
A fuel injection valve for injecting fuel into the main intake passage on the intake downstream side of the main throttle valve;
A sub-intake supply port for supplying air in a direction that collides with a spray bundle of fuel injected from the fuel injection valve on the intake downstream side of the main throttle valve;
A sub-throttle valve that quantitatively controls the flow rate of air supplied to the sub-intake supply port according to the valve opening amount;
A required air amount calculating means for calculating a required air amount according to the operating state of the internal combustion engine;
In the operating range where the required air amount calculated by the required air amount calculating means is less than a predetermined value, the main throttle valve is fully closed and only the valve opening amount of the sub throttle valve is controlled according to the required air amount. And a throttle valve control means for controlling the valve opening amount of the main throttle valve in accordance with the required air amount while maintaining the valve open state of the sub throttle valve in the operation range where the required air amount is a predetermined value or more;
An internal combustion engine fuel injection-intake device.   2. The fuel injection-intake apparatus for an internal combustion engine according to claim 1, wherein the main intake passage is provided for each of a plurality of cylinders constituting the combustion chamber, and the main throttle valve is provided for each of the main intake passages. .   An injection valve mounting member that is formed with the main intake passage and an injection valve insertion hole that is connected to the main intake passage and into which the tip of the fuel injection valve is inserted; The fuel injection-intake device for an internal combustion engine according to claim 1 or 2, wherein a fuel injection port of a fuel injection valve is disposed, and the auxiliary intake supply port is opened in the injection valve insertion hole.   A cylindrical injection hole adapter in which a spray diffusion chamber of fuel injected from the fuel injection port of the fuel injection valve is formed is attached to the injection valve insertion hole, and the sub-wall is defined on a peripheral wall defining the spray diffusion chamber. The fuel injection-intake device for an internal combustion engine according to claim 3, wherein an intake supply port is formed.   Two intake ports are formed for each cylinder, and the main intake passage communicates with the two intake ports for each cylinder, and the auxiliary intake supply is performed on a virtual plane orthogonal to the arrangement direction of the two intake ports. The fuel injection-intake apparatus for an internal combustion engine according to any one of claims 1 to 4, wherein two ports are formed so as to face each other.

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