JP2006188995A - Intake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent sticking of fuel to an inner wall surface of an intake passage such as an intake port. <P>SOLUTION: The inside of a cylinder has a combustion chamber 106, the intake passage such as the intake port 102i having a fuel injection valve 2 for injecting and supplying fuel into the combustion chamber 106 and an intake valve 107 for making air flow in the combustion chamber 106 and stopping the inflow, used for an internal combustion engine 100 for igniting a combustible air-fuel mixture mixed with the air and the fuel by ignition and introducing the air into the intake valve 107, and an oil repellent member 120 for repelling the fuel sticking to an inner wall 102i surface in the intake port 102i. The boil repellent member 120 is arranged on an inner wall 102i of a fuel-sticking part among an inner wall of the intake passage. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an intake device, and is suitable for application to an intake device that introduces intake air into an intake pipe of an internal combustion engine, for example, and is supplied with fuel by a fuel injection device such as a fuel injection valve.

  As an internal combustion engine, for example, a so-called intake pipe in which injected fuel is indirectly supplied to a combustion chamber by being injected into an intake passage such as an intake pipe or an intake port as an intake apparatus by a fuel injection device such as a fuel injection valve. Injection internal combustion engines (also called ports) are known. In this type of intake device, the fuel supplied from the fuel injection device is mixed with air in the intake passage, and the air and the fuel form a combustible mixture in the combustion chamber. The combustible air-fuel mixture in the combustion chamber is compressed by piston motion, and then ignited and combusted by an ignition device, and is used as power for the internal combustion engine. For example, it is known that if fuel adheres to the intake pipe during start-up and cold, the start-up performance, fuel consumption, and exhaust characteristics of the engine are greatly affected. Since there is fuel adhesion in the intake pipe, it is necessary to inject more fuel than the fuel required for the engine. This extra fuel injection deteriorates engine startability, fuel consumption, and exhaust characteristics.

  As a countermeasure, the technique disclosed in Patent Document 1 promotes atomization of the fuel spray injected from the fuel injection valve by devising the valve portion structure of the fuel injection valve and reduces the fluid force of the intake flow flowing in the intake passage. It is used to form a spray corresponding to the shape of the intake passage, that is, the intake pipe.

In general, fuel injection is performed when the intake valve of the internal combustion engine is opened (hereinafter referred to as valve-opened injection) and when the intake valve is closed (hereinafter referred to as valve-closed injection). There is.
JP 2001-317434 A

  However, in the prior art disclosed in Patent Document 1, when performing valve-opening injection, since the atomization level of the spray at the time of using the airflow is still insufficient, the exhaust gas such as HC is compared with the case where valve-closing injection is performed. The gas component may increase. In addition, when performing valve-closed injection, the HC emission characteristics are improved, but the residence time in the intake pipe becomes longer, so the opportunity of fuel adhesion to the inner wall of the intake pipe is not eliminated, so startability and response It may be difficult to ensure performance.

  The present invention has been made in view of such circumstances, and an object thereof is to prevent fuel from adhering to an inner wall surface of an intake passage such as an intake pipe and an intake port.

  Another object is to provide an intake device that prevents the fuel from adhering to the inner wall surface of the intake passage and the like and has a simple prevention structure.

  Still another object is to provide an intake device that can prevent fuel from adhering to the inner wall surface of the intake passage regardless of whether the injection of the fuel injection device is open injection or closed injection of the intake valve. is there.

  In order to achieve the above object, the present invention comprises the following technical means.

The invention according to any one of claims 1 to 3 includes a combustion chamber in the cylinder, a fuel injection device that injects and supplies fuel to the combustion chamber, and an intake valve that flows in and stops the flow of air into the combustion chamber. Used for internal combustion engines that ignite by igniting a combustible air-fuel mixture
An intake passage that guides air to the intake valve, and an oil-repellent member that repels fuel adhering to the inner wall surface in the intake passage, and an oil-repellent member is provided in a portion of the inner wall to which the fuel adheres It is a feature.

  As a result, even if the fuel injected into the intake passage such as the intake pipe from the fuel injection device such as the fuel injection valve tends to adhere to the inner wall surface in the intake passage, The inner wall can have oil repellency that repels fuel. Therefore, even if the fuel tends to adhere to the inner wall surface in the intake passage, the fuel can be prevented from adhering to the inner wall.

  The oil repellent member may be made of the same material as the material forming the inner wall or may be made of a material different from the material forming the inner wall.

  Further, the invention according to claim 2 is characterized in that the portion to which the fuel adheres has a fractal structure on the inner wall surface.

  According to this, it is preferable that the inner wall surface has a fractal structure as a method of providing the oil-repellent member on the portion of the inner wall where the fuel adheres. Thereby, the inner wall surface can be formed by the fractal structure so that the unevenness is a nested structure. For example, the fine nest-like uneven structure formed on the inner wall surface and the surface tension of the fuel droplets can prevent the fuel droplets from entering the inside of the surface, and therefore can have oil repellency.

  Further, the invention according to claim 3 is characterized in that the portion to which the fuel adheres is given oil repellency by coating the surface of the inner wall.

  In some cases, the inner wall of the intake passage such as the intake pipe cannot be formed directly on the resin material or on the inner wall.

  On the other hand, in the invention described in claim 3, oil repellency can be imparted by coating the inner wall surface. For example, a fractal structure can be formed in the coating layer by performing a crystallization process after coating the inner wall surface using a coating material such as an alkyl ketene dimer.

Further, the invention according to claim 4 includes a combustion chamber in the cylinder, a fuel injection device that injects and supplies fuel to the combustion chamber, and an intake valve that flows in and stops the flow of air into the combustion chamber, Used for internal combustion engines that ignite by igniting a combustible air-fuel mixture
An oil repellent member that repels fuel adhering to the intake valve is provided, and the oil repellent member is provided on the surface of the intake valve.

  In general, when the intake valve is closed on the inner wall surface in the intake passage that guides air to the intake valve, the surface on the intake passage side of the intake valve among the surface on the combustion chamber side and the surface on the intake passage side of the intake valve is combusted. An inner wall surface of the intake passage in which the flow path to the chamber is closed is formed.

  On the other hand, in the invention according to claim 4, since the oil-repellent member is provided on the surface of the intake valve, the fuel will adhere to the intake valve constituting the inner wall surface in the intake passage. Even if there is a case, it is possible to prevent the fuel from adhering to the intake valve.

  According to a fifth aspect of the present invention, the intake device according to any one of the first to third aspects further comprises an oil repellent member that repels fuel adhering to the intake valve, and the oil repellent member is It is provided on the surface of the valve.

  According to this, the intake device according to any one of claims 1 to 3, further comprising an oil repellent member that repels fuel adhering to the intake valve, and the oil repellent member is provided on a surface of the intake valve. It is preferable. Thereby, even if the fuel tends to adhere to the inner wall surface including the intake valve in the intake passage, the fuel can be prevented from adhering to the inner wall.

According to a sixth aspect of the present invention, in the intake device according to any one of the first to fifth aspects, the fuel injection device includes a control unit that controls fuel injection of the fuel injection device. ,
When the intake valve is opened, the fuel injection of the fuel injection device is performed by the control means.

  As a result, the portion of the inner wall in the intake passage where the fuel can adhere is given oil repellency, so that when the intake valve is opened, the atomization level of the spray at the time of using the air flow is still Even if it is insufficient, there can be no fuel adhering to the inner wall. Therefore, it is possible to prevent the fuel droplets adhering to the inner wall from forming a drop or the like as in the prior art and dropping into the combustion chamber at a time inappropriate for the operating state of the internal combustion engine. As a result, an increase in exhaust gas components such as HC can be prevented.

According to a seventh aspect of the present invention, in the intake device according to any one of the first to fifth aspects, the fuel injection device includes a control unit that controls fuel injection of the fuel injection device. ,
The fuel injection of the fuel injection device is performed by the control means when the intake valve is closed.

  In general, there is a case in which fuel injection is performed when the intake valve is closed, and then the intake valve is opened and the atomization of the fuel spray advances and the air flow is desired to be used. In this case, since the fuel spray stays in the intake passage until the intake valve is opened, there is a problem that the opportunity of fuel adhesion to the inner wall of the intake pipe is not eliminated.

  On the other hand, in the invention according to claim 7, even if there is a period until the intake valve is opened after the fuel injection is performed by the control means when the intake valve is closed, the fuel on the inner wall in the intake passage Since the oil repellent property is imparted to the portion of the inner wall to which the fuel can adhere, it is possible to prevent the fuel spray droplets from adhering to the inner wall.

  Hereinafter, embodiments in which the intake device of the present invention is embodied will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic cross-sectional view showing the overall configuration of an internal combustion engine to which the intake device of the present embodiment is applied. FIG. 2 is a partial cross-sectional view of the inner wall in the intake passage in FIG. 1, and is a schematic cross-sectional view showing a state in which fuel droplets are dropped on the surface of the inner wall. FIG. 3 is a schematic enlarged cross-sectional view showing a contact state between the droplet in FIG. 2 and the inner wall surface. FIG. 4 is a schematic diagram for explaining the operation process of the intake device and the fuel injection device of the internal combustion engine according to the present embodiment.

  FIG. 6 is a schematic cross-sectional view showing an internal combustion engine using a conventional intake device. In FIG. 1 and FIG. 6, the state in which the fuel is injected from the fuel injection device is shown for comparison explanation of the adhesion state of the injected fuel on the inner wall between the present embodiment and the prior art.

  As shown in FIG. 1, the intake device is used in an internal combustion engine 100 that obtains power by fuel supply, particularly a gasoline engine. For example, the intake device is used in a multi-cylinder (for example, four-cylinder) gasoline engine (hereinafter referred to as an engine) 100. A device for inhaling air for mixing with fuel. In addition, the intake device forms a combustible air-fuel mixture in the combustion chamber 106 with the air and fuel.

  As shown in FIG. 1, the engine 100 includes a cylinder block 101, a cylinder head 102, a piston 104, an inner peripheral wall of a cylinder block (hereinafter referred to as a cylinder) 101, a piston 104 and a ceiling inner wall of the cylinder head 102. This is a known internal combustion engine including a combustion chamber 106 that is partitioned and an ignition device 105 that ignites a combustible air-fuel mixture or fuel. The reciprocating motion of the piston 104 in the inner peripheral wall of the cylinder 101 is converted into a continuous rotational motion of a crankshaft (not shown) via a connecting rod (not shown). The volume of the combustion chamber 106 increases and decreases as the piston 104 reciprocates. Here, FIG. 1 shows only one of the four cylinders in the drawing. The ignition device 105 is a device for ignition having a known structure having a spark plug and the like. The ignition device 105 ignites to ignite a combustible mixture or fuel in which air and fuel formed in the combustion chamber 106 are mixed.

  As shown in FIG. 1, the cylinder head 102 is connected to an intake pipe (not shown) that forms a passage through which intake air flows, and forms an intake port 102i through which intake air is guided, and a passage through which combustion gas and the like flow. An exhaust port 102e is connected to an exhaust pipe (not shown) and exhausts exhaust.

  As shown in FIG. 1, an intake valve (hereinafter referred to as an intake valve) 107 is seated on and separated from the inner wall of the intake port 102i, so that intake air or fuel and air introduced to the intake port 102i are mixed. The flow of the combustible air-fuel mixture to the combustion chamber 106 is blocked and allowed. In detail, as shown in FIG. 1, the intake valve 107 is fixed to the shaft portion 107b, which is reciprocally moved by an intake camshaft (not shown), for example, and the inner wall of the intake port 102i (specifically, the inner wall The seat portion) has a face portion 107a that is seated and separated from the seat portion, and a predetermined gap is formed between the seat portion and the face portion 107a in accordance with the amount of valve lift that the intake valve 107 moves axially.

  Similarly, an exhaust valve (hereinafter referred to as an exhaust valve) 109 is fixed to the shaft portion 109b, which is reciprocally moved by an unillustrated exhaust camshaft, and the shaft portion 109b, and the inner wall (specifically, the inner wall of the exhaust port 102e). The seat portion) has a face portion 109a that is seated and separated from the seat portion. For example, the seat portion and the face portion 109a are opened in response to a valve lift amount that the exhaust valve 109 moves axially. A predetermined gap is formed between them.

  Here, the intake valve 107 flows in and stops the flow of air or combustible air-fuel mixture into the combustion chamber 106. The seat portion of the intake port 102i and the face portion 107a are separated from and in contact with each other, so that air or a combustible air-fuel mixture flows into and stops flowing into the combustion chamber 106. The exhaust valve 109 discharges and stops the combustion gas from the combustion chamber 106. The seat portion of the exhaust port 102e and the face portion 109a are separated from and in contact with each other, so that the combustion gas from the combustion chamber 106 is discharged and stopped. Further, the intake pipe and the intake port 102i constitute an intake passage described in the claims. The inner wall 102i in the intake port 102 constitutes a portion to which fuel adheres among the inner walls in the intake passage described in the claims.

  The intake valve 107, the intake camshaft, the exhaust valve 109, and the exhaust camshaft may have any structure as long as the drive valve device has a known structure. The drive valve device opens the intake valve 107 and closes the exhaust valve 109 in the intake stroke of the engine 100, for example. Further, in the compression stroke and the combustion stroke, the intake valve 107 and the exhaust valve 109 are closed. Note that two intake valves 107 and two exhaust valves 109 may be arranged for each cylinder, or one for each.

  As shown in FIGS. 1 and 2, the inner wall 102ih of the intake port 102i includes an oil-repellent member 120 that repels fuel droplets. The oil repellent member 120 may be made of the same material as the material forming the inner wall 102ih or may be made of a material different from the material forming the inner wall 102ih. In the following description of the present embodiment, the oil repellent member 120 is made of the same material as that forming the inner wall 102ih.

  As shown in FIGS. 2 and 3, the inner wall 102ih (specifically, the oil-repellent member 120) has a fractal structure on the inner wall surface. Specifically, as shown in FIG. 3, the inner wall surface 120a having a fractal structure has surface irregularities 120af formed in a nested structure. The fractal structure has a self-similarity in which the surface unevenness 120af is a nested structure. The surface by the fractal structure theoretically has an infinite surface area, but in practice, it is finite within the actual surface area that is formed comparatively very widely according to the surface shape of the nesting irregularities 120af. .

  The contact relationship between the inner wall surface 120a and the fuel droplets shown in FIG. 3 will be described. The inner wall surface 120a and the fuel are separated by the fine nested unevenness 120af structure formed on the inner wall surface 120a and the surface tension of the fuel droplets. A gas layer of air is formed between the surface of the droplet. As a result, it becomes impossible to prevent the fuel droplets from entering the inside of the surface, so that the inner wall surface 120a can have an oil repellency function.

  As a method for forming the fractal structure, for example, when the intake port 102i is formed of an aluminum alloy, the inner wall surface 120a is formed into a fractal structure by anodizing the inside of the intake port 102i.

  The engine 100 described below is a port injection engine in which fuel is indirectly injected into the combustion chamber 106. The fuel injected from the fuel injection valve 2 is supplied by injection into the intake port 102i.

  As shown in FIG. 1, the fuel injection valve 2 as a fuel injection device is provided on the intake port 102 i side of the cylinder head 102. The fuel injection valve 2 is supplied with fuel pressurized by a fuel pump (not shown) via a fuel distribution pipe (not shown). The fuel injection valve 2 has a substantially cylindrical shape as shown in FIG. 1, receives fuel from one end, and injects fuel from the other end. As shown in FIG. 1, the fuel injection valve 2 includes a valve portion 2a for blocking and allowing fuel injection and an electromagnetic drive portion 2b for driving the valve portion 2a. It is. When the engine 100 is a direct injection engine, the fuel injection valve 2 directly supplies fuel to the combustion chamber 106. In this case, in order to set the pressure of the fuel supplied to the combustion chamber 106 to about 2 MPa or more, a predetermined low pressure (for example, 0.2 MPa) fuel sucked up from the fuel tank by the fuel pump is further supplied by a high pressure pump (not shown). Pressurized, and this pressurized predetermined high-pressure fuel (for example, a fuel having a predetermined pressure in the range of 2 to 13 MPa) is supplied to the fuel injection valve 2 via the fuel distribution pipe. The fuel discharged from the fuel pump and the fuel discharged after being further pressurized from the high-pressure pump are each adjusted to a predetermined pressure by a pressure regulator as a fuel pressure adjusting device (not shown).

  The valve portion 2a is a well-known valve portion having a nozzle needle and a valve body that accommodates the nozzle needle in an axially movable manner. The valve part 2a has the injection hole 21 which injects and atomizes fuel. Specifically, a nozzle hole 21 penetrating inward and outward is provided in the valve body. The nozzle holes 21 are not limited to those formed in the valve body, but may be arranged on the tip side of the valve body and formed in a substantially thin plate-like nozzle hole plate. Here, the valve needle 2a opens and closes when the nozzle needle is separated and seated on the valve body. When the valve portion 2a is opened and closed, the valve portion 2a, that is, the fuel injection valve 2 blocks and allows the flow of fuel (fuel injection) supplied to the inside. Further, the valve portion 2a and the injection hole 21 constitute a tip portion for injecting fuel of the fuel injection valve 2.

  The size of the nozzle hole 21, the direction of the nozzle hole axis, the nozzle hole arrangement, and the like are determined in accordance with the required fuel spray shape, direction, number, and the like. The opening area of the nozzle hole defines the flow rate when the valve is opened. The fuel injection amount of the fuel injection valve 2 is measured by the opening area of the opened nozzle hole, the lift amount of the nozzle needle (hereinafter referred to as the needle lift amount), and the valve opening period. When the nozzle needle is seated on the valve body and the valve portion 2a is closed, fuel injection from the nozzle hole 21 is interrupted, and when the nozzle needle is separated from the valve body and the valve portion 2a is opened, fuel from the nozzle hole 21 is opened. Injection is allowed and fuel is injected. Here, the nozzle hole 21 constitutes a fuel spray forming means for atomizing the fuel to form a spray.

  As shown in FIG. 1, the electromagnetic drive unit 2b includes a movable core (not shown) that cooperates with the nozzle needle, a fixed core (not shown) that movably accommodates the movable core, and a movable core and a fixed core. This is an electromagnetic drive unit having a well-known structure having a coil (not shown) that acts on the core to act on electromagnetic force. The electromagnetic drive unit 2b includes a lift adjustment mechanism for regulating the maximum movement amount of the needle lift, such as adjusting an axial gap (hereinafter referred to as an air gap) between the movable core and the fixed core. Yes. The nozzle needle is biased in the valve closing direction by a biasing member such as a spring that biases the movable core toward the nozzle hole 21, and the nozzle needle, that is, the fuel injection valve 2 is biased when the coil is not energized. The valve is closed by the biasing force of the member. The fuel injection valve 2 includes an urging force adjusting mechanism (not shown) that adjusts the urging force of the urging member. When the coil is energized, an electromagnetic force is generated in the coil, and an electromagnetic attractive force acts between the fixed core and the movable core. Therefore, the needle lift amount increases in the movable core against the urging force of the urging member. The nozzle needle, that is, the fuel injection valve 2 is opened.

  An ECU (not shown) as a control means is known in which a read only memory (ROM), a random access memory (RAM), a microprocessor (CPU), an input port, and an output port (not shown) are connected to each other via a bidirectional bus. It is comprised as a microcomputer of the structure. In addition, ECU comprises the control means as described in a claim.

  This ECU controls the energization period of the fuel injection valve 2 by starting and stopping energization of the coil of the fuel injection valve 2 using a power source such as a battery. Fuel signals are injected in accordance with various engine programs (not shown) by reading signals from various sensors (not shown) that detect engine operating conditions such as the rotational speed of the engine 100, intake pipe pressure (or intake air amount), and cooling water temperature. The operation of the electromagnetic drive unit 2b of the valve 2 is controlled. Specifically, a reference position sensor (not shown) that outputs a pulse signal every 720 ° CA according to the rotational state of the crankshaft, and a pulse signal every finer crank angle (for example, every 30 ° CA). Is provided with a rotation angle sensor (not shown). The cylinder 101 (water jacket) or the like is provided with a water temperature sensor (not shown) for detecting the cooling water temperature. The intake pipe is provided with an air flow meter (not shown) for detecting the intake air flow rate. The exhaust pipe is provided with an air-fuel ratio sensor (not shown) that outputs an air-fuel ratio signal in proportion to the oxygen concentration in the exhaust gas. In addition, an accelerator pedal sensor (not shown), a throttle opening sensor (not shown), and the like for detecting a driver's request and the like are provided. It should be noted that the load state of engine 100 is determined by the ECU based on signals from various sensors that detect engine speed, intake air amount, air-fuel ratio sensor, and the like.

  Here, if the ECU indicates the function executed by the program as the main means, the fuel injection control means for controlling the injection operation of the fuel injection valve 2 and the ignition control means for controlling the ignition operation of the ignition device 105 It consists of and.

  Here, the operation of the intake device of the engine 100 and the operation of the fuel injection valve 2 will be described with reference to FIG. 4. In the combustion cycle of the engine 100, the fuel injection valve 2 operates in the exhaust stroke, the intake stroke, the compression stroke, and the explosion. It is injected during the intake stroke of the stroke. Specifically, fuel is injected from the fuel injection valve 2 when the intake valve 107 constituting the intake device is opened. Thereafter, the intake valve 107 is closed. Hereinafter, this injection during the intake stroke is referred to as valve-opening injection.

  Next, the operation and effect of this embodiment will be described. (1) In this embodiment, an intake passage for guiding air to the intake valve and an oil repellent member that repels fuel adhering to the inner wall surface in the intake passage are provided. An oil repellent member is provided on a portion of the inner wall where the fuel adheres. In this embodiment, the oil repellent member 120 is made of the same material as that for forming the inner wall 102ih.

  As a result, an oil-repellent function that repels fuel on the inner wall surface 120a of the portion where the fuel can adhere in the fuel injection device such as the fuel injection valve 2 that is injected into the intake pipe or the intake passage such as the intake port 102i. Can be given. Therefore, even if the injected fuel tends to adhere to the inner wall 102ih surface in the intake port 102i, the fuel can be prevented from adhering to the inner wall 102ih (specifically, the inner wall surface 120a).

  (2) In this embodiment, as a method of providing the oil-repellent member 120 on the portion of the inner wall 120ih where the fuel adheres, it is preferable that the surface of the inner wall 120ih (specifically, the inner wall surface 120a) has a fractal structure. Thereby, the inner wall surface 120a can be formed by the fractal structure so that the unevenness 120af has a nested structure. Due to the fine nested unevenness 120af structure formed on the inner wall surface 120a and the surface tension of the fuel droplets, the fuel droplets can be prevented from entering the inside of the surface, and therefore oil repellency can be provided.

  (3) Further, in the present embodiment, the ECU includes a fuel injection control means for controlling the injection operation of the fuel injection valve 2. Further, the operation process of the intake device of the engine 100 and the fuel injection valve 2 is so-called valve-opening injection in which the fuel injection of the fuel injection valve 2 is performed when the intake valve 107 is opened. Specifically, in the combustion cycle of the engine 100, the fuel injection valve 2 is injected during the intake stroke among the exhaust stroke, the intake stroke, the compression stroke, and the explosion stroke. When the intake valve 107 is opened, the ECU Thus, fuel is injected from the fuel injection valve 2. Thereafter, the intake valve 107 is closed.

  As a result, the inner wall 120ih to which fuel can adhere is provided with an oil repellency function, so that when the intake valve 107 is opened, the atomization level of the spray at the time of using the air flow is still insufficient. Even if there is, there can be no fuel adhering to the inner wall 120ih (see FIG. 1). Therefore, conventional fuel droplets adhering to the inner wall form drops (see FIG. 6) and the like, and can be prevented from dropping into the combustion chamber at a time inappropriate for the operating state of the internal combustion engine. . As a result, an increase in exhaust gas components such as HC can be prevented.

(Second Embodiment)
Hereinafter, other embodiments to which the present invention is applied will be described. In the following embodiments, the same or equivalent components as those in the first embodiment are denoted by the same reference numerals, and description thereof will not be repeated.

  In the second embodiment, in the operation relationship between the intake device of the engine 100 and the fuel injection valve 2 described in the first embodiment, instead of valve opening injection, so-called valve closing injection is used as shown in FIG. FIG. 5 is a schematic diagram for explaining the operation process of the intake device and the fuel injection device of the internal combustion engine according to the present embodiment.

  As shown in FIG. 5, the closed injection of the fuel injection valve 2 is injected during the exhaust stroke of the exhaust stroke, the intake stroke, the compression stroke, and the explosion stroke in the combustion cycle of the engine 100. Specifically, fuel is injected from the fuel injection valve 2 when the intake valve 107 constituting the intake device is closed. Thereafter, the intake valve 107 is opened.

  Next, the operation and effect of the present embodiment will be described. (1) In general, fuel injection is performed when the intake valve 107 is closed, and then the intake valve 107 is opened and the atomization of the fuel spray advances and the air is injected. There are cases where it is desired to perform closed-time injection using airflow. In this case, since the fuel spray stays in the intake port 102i until the intake valve 107 is opened, there is a problem that the opportunity of fuel adhesion to the inner wall 102ih is not eliminated.

  On the other hand, in the present embodiment, even when there is a period until the intake valve 107 is opened after the fuel injection from the fuel injection valve 2 is performed by the ECU when the intake valve 107 is closed, the oil repellent property is applied to the inner wall 102ih. Therefore, the fuel spray droplets can be prevented from adhering to the inner wall 102ih.

(Other embodiments)
In the present embodiment described above, the inner wall surface 120a is formed into a fractal structure by anodizing the inside of the intake port 102i as a method for imparting an oil repellency function to the inner wall 120ih. Other forming methods may be used. The coating 120 is applied to the inner wall 120ih. Thereby, the surface 120a of the coating 120 layer can have an oil repellency function. For example, a fractal structure can be formed in the coating 120 layer by performing a crystallization process after coating the inner wall surface using a coating material such as an alkyl ketene dimer. In this case, the inner wall 120ih is effective when the fractal structure cannot be directly formed on the resin material or the inner wall 120ih.

  In general, of the inner wall surface 102i in the intake port 102i that guides air to the intake valve 107, when the intake valve 107 is closed, of the surface on the combustion chamber 106 side and the surface on the intake port 102i side of the intake valve 107 The surface on the intake port 102i side forms the inner wall surface of the intake port 102i in which the flow path to the combustion chamber 106 is closed. Therefore, as another embodiment, the surface of the intake valve 107 may be configured to have an oil repellency function. As a result, even if the fuel tends to adhere to the intake valve 107 constituting the inner wall surface in the intake port 102 i, it is possible to prevent the fuel from attaching to the intake valve 107.

  Furthermore, in the present embodiment described above, the surface of the intake valve 107 may be configured to have an oil repellency function. Thereby, even if the fuel tends to adhere to the inner walls 102i, 107 including the intake valve 107 in the intake port 102i, the fuel can be prevented from adhering to the inner walls 102i, 107.

  Furthermore, in the present embodiment described above, it is possible to prevent the fuel from adhering to the inner wall of the intake passage such as the intake port 102i with a simple structure without changing the intake flow or the structure of the fuel injection valve 2.

1 is a schematic cross-sectional view showing an overall configuration of an internal combustion engine to which an intake device according to a first embodiment of the present invention is applied. FIG. 2 is a partial cross-sectional view of an inner wall in an intake passage in FIG. 1, and is a schematic cross-sectional view showing a state in which fuel droplets are dropped on the surface of the inner wall. It is a typical expanded sectional view which shows the contact state of the droplet in FIG. 2, and an inner wall surface. It is a schematic diagram explaining the process of operation | movement of the intake device and fuel-injection apparatus of an internal combustion engine concerning 1st Embodiment. It is a schematic diagram explaining the process of operation | movement of the intake device and fuel-injection apparatus of an internal combustion engine concerning 2nd Embodiment. It is typical sectional drawing which shows the internal combustion engine using the intake device of a prior art.

Explanation of symbols

100 engine (internal combustion engine)
101 cylinder (cylinder block)
101a Inner peripheral surface 102 Cylinder head 102i Intake port 102ih Inner wall 107 Intake valve (intake valve)
107a Face portion 107b Shaft portion 120 Oil repellent member 120a Inner wall surface 120af Concavity and convexity 2 Fuel injection valve 2a Valve portion 2b Electromagnetic drive portion

Claims (7)

A combustion chamber in a cylinder, a fuel injection device that injects and supplies fuel to the combustion chamber, and an intake valve that flows in and stops the flow of air into the combustion chamber, and ignites a combustible mixture in which air and fuel are mixed Used for internal combustion engines ignited by
An intake passage for guiding air to the intake valve;
An oil repellent member that repels fuel adhering to the inner wall surface in the intake passage;
An air intake apparatus, wherein the oil repellent member is provided in a portion of the inner wall to which fuel adheres. The intake device according to claim 1, wherein an inner wall surface of the portion to which the fuel adheres has a fractal structure. 2. The intake device according to claim 1, wherein the portion to which the fuel adheres has oil repellency by coating the inner wall surface. A combustion chamber in a cylinder, a fuel injection device that injects and supplies fuel to the combustion chamber, and an intake valve that flows in and stops the flow of air into the combustion chamber, and ignites a combustible mixture in which air and fuel are mixed Used for internal combustion engines ignited by
An oil repellent member that repels fuel adhering to the intake valve;
An air intake apparatus, wherein the oil repellent member is provided on a surface of the intake valve. In the inhalation device according to any one of claims 1 to 3,
An oil repellent member that repels fuel adhering to the intake valve;
An air intake apparatus, wherein the oil repellent member is provided on a surface of the intake valve. In the inhalation device according to any one of claims 1 to 5,
The fuel injection device comprises control means for controlling fuel injection of the fuel injection device,
An intake device according to claim 1, wherein when the intake valve is opened, fuel injection of the fuel injection device is performed by the control means. In the inhalation device according to any one of claims 1 to 5,
The fuel injection device comprises control means for controlling fuel injection of the fuel injection device,
The intake device, wherein when the intake valve is closed, the fuel injection of the fuel injection device is performed by the control means.

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