JP2007291941A - Internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine in which the adhesion of a fuel onto an intake valve is reduced. <P>SOLUTION: This internal combustion engine comprises a fuel injection device 41 for injecting a fuel into an intake port 11b or/and a combustion chamber CC and an intake valve 31 disposed in a flow passage for the fuel injected from the fuel injection valve 41 or moving in the flow passage. The internal combustion engine further comprises a valve temperature measuring means for measuring the distribution of the temperatures of the intake valve 31 or a valve temperature estimating means (electronic control device 1) for estimating the distribution of the temperatures, and a valve rotating means 32 for rotating the intake valve 31 around the axis of a valve system to move the high temperature portion of the intake valve 31 into the flow passage for the fuel from the fuel injection device 41. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an internal combustion engine in which an intake valve exists on a flow path of fuel from a fuel injection device.

  Conventionally, in an internal combustion engine, in order to achieve good combustion according to various operating conditions such as the engine speed, various controls are performed to form an air-fuel ratio air-fuel mixture corresponding to the operating conditions in the combustion chamber. It has been done.

  Patent Document 1 below discloses a technique for promoting the rotation of the intake valve in the circumferential direction in order to make the temperature of the intake valve uniform and reduced. Also, in Patent Document 2 below, a spiral groove is provided in the valve stem for the purpose of preventing the inclusion of carbon or other solid matter in the face and valve seat of the valve body, and the valve body is interlocked with the reciprocating movement of the valve. A technique for rotating in the circumferential direction is disclosed. Patent Documents 3 and 4 listed below disclose techniques for rotating a valve in the circumferential direction for the purpose of suppressing uneven wear of the valve and its related parts. In Patent Document 4, the valve is rotated by electromagnetic driving means.

Japanese Patent Laid-Open No. 8-14014 Japanese Utility Model Publication No. 63-118314 JP-A-8-21213 JP-A-8-135417

  However, in the conventional internal combustion engine, a part of the sprayed fuel from the fuel injection device is not vaporized and adheres to the intake valve (particularly, the umbrella portion). However, the actual air-fuel ratio becomes sparse, and unless the air-fuel ratio control is performed by taking into account the deviation width and performing the air-fuel ratio control, it is not possible to realize good combustion according to the operating conditions. Therefore, this conventional internal combustion engine has poor air-fuel ratio controllability such as a response delay, and the combustion state must be made good by other combustion control.

  Therefore, an object of the present invention is to provide an internal combustion engine that can improve the disadvantages of the conventional example and reduce the adhesion of fuel to the intake valve.

  In addition, the above-mentioned Patent Document 1 describes that if the temperature of a part of the intake valve becomes particularly high, it causes unauthorized combustion. What is the specific cause of the unauthorized combustion, There is no disclosure of how the temperature can be made uniform and reduced by rotating the valve. However, the invention of Patent Document 1 is aimed at equalizing and reducing the temperature of the intake valve, and is greatly different from the viewpoint of fuel vaporization promotion using a high-temperature portion in the present invention described later. Therefore, the object is different from the present invention. In addition, the objects of the above Patent Documents 2 to 4 are different from those of the present invention.

  In order to achieve the above object, according to the first aspect of the present invention, a fuel injection device that injects fuel into the intake port or / and the combustion chamber, and a fuel injection device that is disposed on a flow path of the fuel injected from the fuel injection device, or In an internal combustion engine equipped with an intake valve that moves on a flow path, a valve temperature measuring means for measuring a temperature distribution of the intake valve or a valve temperature estimating means for estimating the temperature distribution, and a fuel temperature from the fuel injection device Valve rotating means for rotating the intake valve about the axis of the valve stem to move the high temperature portion of the intake valve on the flow path is provided.

  In the internal combustion engine according to the first aspect, the sprayed fuel hits the high temperature portion of the intake valve, and the fuel is vaporized in the high temperature portion of the intake valve, so that the adhesion of liquid fuel to the intake valve is reduced.

  In order to achieve the above object, according to a second aspect of the present invention, in the internal combustion engine according to the first aspect, the valve rotation means is provided to execute the rotation operation of the intake valve in accordance with the fuel injection timing of the fuel injection device. It is composed.

  In the internal combustion engine according to the second aspect, for example, if the intake valve is rotated before the fuel injection is started, the sprayed fuel is surely applied to the high temperature portion of the intake valve, and the liquid fuel is applied to the intake valve. Adhesion can be reliably reduced. In this internal combustion engine, for example, if the intake valve is rotated during the fuel injection period, the sprayed fuel is likely to be vaporized because it hits a higher temperature portion, and the liquid fuel adheres to the intake valve efficiently. Can be reduced.

  In the internal combustion engine according to the present invention, the sprayed fuel hitting the intake valve is vaporized using the high temperature portion, and this is sent as an air-fuel mixture into the combustion chamber. For this reason, in this internal combustion engine, the adherence of liquid fuel to the intake valve is reduced, and it becomes possible to bring the actual air-fuel ratio closer to the air-fuel ratio according to the operating conditions. It becomes possible to realize proper combustion.

  Embodiments of an internal combustion engine according to the present invention will be described below in detail with reference to the drawings. The present invention is not limited to the embodiments.

  A first embodiment of an internal combustion engine according to the present invention will be described with reference to FIGS.

  This internal combustion engine is subjected to combustion control and the like by an electronic control unit (ECU) 1 shown in FIG. The electronic control unit 1 includes a CPU (central processing unit) (not shown), a ROM (Read Only Memory) that stores a predetermined control program and the like, a RAM (Random Access Memory) that temporarily stores a calculation result of the CPU, It is composed of a backup RAM or the like for storing information prepared in advance.

  First, the configuration of the internal combustion engine exemplified here will be described.

  The internal combustion engine includes a cylinder head 11, a cylinder block 12, and a piston 13 that form a combustion chamber CC. Here, the cylinder head 11 and the cylinder block 12 are fastened with bolts or the like via the head gasket 14 shown in FIG. 1, and the recess 11a on the lower surface of the cylinder head 11 and the cylinder bore 12a of the cylinder block 12 formed thereby. The piston 13 is disposed so as to be capable of reciprocating in the space. And the combustion chamber CC mentioned above is comprised by the space enclosed by the wall surface of the recessed part 11a of the cylinder head 11, the wall surface of the cylinder bore 12a, and the top surface 13a of the piston 13. FIG.

  Air from the outside is introduced into the combustion chamber CC via the intake passage 21 and the intake port 11b of the cylinder head 11 shown in FIG.

  Here, on the intake passage 21, an air cleaner 22 for removing foreign matters such as dust from the introduced external air, and an air flow meter 23 for detecting the amount of intake air from the outside are provided. In this internal combustion engine, the detection signal of the air flow meter 23 is sent to the electronic control unit 1, and the electronic control unit 1 calculates the amount of intake air from the outside based on the detection signal.

  A throttle valve 24 that adjusts the amount of intake air into the combustion chamber CC and a throttle valve actuator 25 that opens and closes the throttle valve 24 are provided downstream of the air flow meter 23 on the intake passage 21. It has been. The electronic control unit 1 instructs the throttle valve actuator 25 to control the opening angle of the throttle valve 24, and sucks a desired intake air amount corresponding to the opening angle into the combustion chamber CC. In this internal combustion engine, a throttle opening sensor 26 for detecting the opening of the throttle valve 24 is provided, and a detection signal of the throttle opening sensor 26 is sent to the electronic control unit 1.

  On the other hand, one end of the intake port 11b opens into the combustion chamber CC, and an intake valve 31 that can open and close the opening is disposed at the opening portion. For example, the intake valve 31 is driven to open and close with the rotation of an intake camshaft (not shown) and the elastic force of an elastic member (string winding spring). In this internal combustion engine, air is sucked into the combustion chamber CC from the intake port 11b by opening the intake valve 31, and the air into the combustion chamber CC is closed by closing the intake valve 31. Inflow is blocked. The number of openings into the combustion chamber CC in the intake port 11b may be one or plural, and an intake valve 31 is provided for each opening.

  Furthermore, in the internal combustion engine of the first embodiment, a fuel injection device 41 that injects fuel into the intake port 11b is provided. In the fuel injection device 41, the fuel injection amount, the fuel injection timing, the fuel injection period, and the like are controlled by the electronic control unit 1. For example, the electronic control device 1 controls the valve opening angle of the throttle valve actuator 25 and the fuel injection amount of the fuel injection device 41 in accordance with the operating conditions of the internal combustion engine, and the mixture of air and fuel generated thereby. The air is sucked into the combustion chamber CC.

  The electronic control device 1 controls the ignition timing of the ignition plug 51 shown in FIG. 1 to execute ignition of the air-fuel mixture formed in the combustion chamber CC. Thereby, in this internal combustion engine, a combustion operation is started. The in-cylinder gas after combustion is discharged from the combustion chamber CC to the exhaust port 11c shown in FIG. Here, an exhaust valve 61 capable of opening and closing an opening between the exhaust port 11c and the combustion chamber CC is disposed. For example, the exhaust valve 61 is driven to open and close with the rotation of an exhaust camshaft (not shown) and the elastic force of an elastic member (string winding spring). Therefore, the in-cylinder gas after combustion is discharged from the combustion chamber CC to the exhaust port 11c by opening the exhaust valve 61, and the in-cylinder gas exhaust port 11c is closed by closing the exhaust valve 61. Is blocked. The number of openings into the combustion chamber CC in the exhaust port 11c may be one or plural, and the exhaust valve 61 described above is provided for each opening.

  Furthermore, the internal combustion engine of the first embodiment is provided with various sensors such as a crank angle sensor 71 that detects the rotation angle of the crankshaft 15 and a water temperature sensor 72 that detects the temperature of the cooling water. The detection signals of these various sensors are also sent to the electronic control unit 1, respectively.

  By the way, the air-fuel mixture in the combustion chamber CC is dense so as to have the best air-fuel ratio required in accordance with the operating conditions and the like in order to execute good combustion control under various operating conditions such as engine speed and load. To be controlled. Hereinafter, the air-fuel ratio is referred to as “required air-fuel ratio”.

  However, since a part of the sprayed fuel injected from the fuel injection device 41 adheres to the intake valve 31 (particularly, the umbrella portion) without being vaporized, the air-fuel ratio of the actually generated air-fuel mixture is the required air. It becomes leaner than the fuel ratio, and if it remains as it is, desired combustion corresponding to the operating conditions cannot be performed. Therefore, in practice, for example, it is necessary to estimate the actually generated air-fuel ratio from the amount of residual oxygen in the exhaust gas, etc., and to correct the actual air-fuel ratio to the required air-fuel ratio by feedback control. The air-fuel ratio controllability is poor.

  On the other hand, the sprayed fuel from the fuel injection device 41 is injected at a predetermined spray angle or injection angle, so that it follows only a predetermined flow path, and the intake valve 31 only reciprocates in the axial direction of the valve stem. Therefore, liquid fuel adheres to the intake valve 31 at a substantially fixed position. In a normal internal combustion engine, liquid fuel does not adhere evenly to the entire intake valve 31 (particularly, the entire umbrella portion), so the temperature distribution of the intake valve 31 is often uneven. It has become. That is, since the temperature of the intake valve 31 is lowered by the latent heat of vaporization of the fuel at the location where the liquid fuel is attached, the temperature difference between the attached location and the non-attached location is affected by the amount of adhesion. It may occur.

  Therefore, in the first embodiment, the intake valve 31 is rotated around the axis of the valve stem, and the sprayed fuel is applied to a portion of the intake valve 31 that is relatively high in temperature so that the liquid fuel In order to reduce adhesion, the following configuration is adopted. Here, a description will be given assuming that a part of the umbrella portion of the intake valve 31 exists on the flow path of the sprayed fuel from the fuel injection device 41.

  In this internal combustion engine, valve rotation means 32 is provided for rotating the intake valve 31 about the axis of the valve stem. As the valve rotating means 32, for example, a driving device that transmits the driving force of an electric motor, the hydraulic pressure of a hydraulic pressure generator, or the like as the rotational force about the axis of the valve stem can be considered.

  The valve rotation means 32 is driven and controlled by the electronic control unit 1.

  Here, when the intake valve 31 is rotated in the valve-closed state, wear occurs between the umbrella portion and the valve seat (seat ring), and the valve rotation means is accompanied by friction therebetween. This is not preferable because the driving force of 32 must be increased wastefully. For this reason, in the first embodiment, the valve rotating means 32 is driven when the intake valve 31 is in the open state (for example, the intake stroke). At this time, whether or not it is the drive timing of the valve rotation means 32 is determined using a known technique that can determine the open state (intake stroke) of the intake valve 31. For example, in the case of the internal combustion engine as in the first embodiment, the electronic control unit 1 uses the information on the rotation angle of the crankshaft 15 and the rotation angle of the intake side camshaft to open the intake valve 31 (intake stroke). Can be judged. In the case of an internal combustion engine provided with a so-called variable valve timing & lift mechanism that can vary the opening / closing timing and lift amount of the intake valve 31, the electronic control unit 1 opens the intake valve 31 with respect to the variable valve timing & lift mechanism. It can be determined from the valve command.

  Specifically, the electronic control device 1 according to the first embodiment can be set to rotate the intake valve 31 at a predetermined rotation angle, for example. In this case, the predetermined rotation angle is set to an angle at which the fuel adhesion area at the umbrella portion of the intake valve 31 is obtained in advance from experiments and simulations, and at least the unadhered portion of the fuel can be moved to the fuel flow path. To do. In addition, when the relative high temperature part exists in the range of the adhesion location rather than the fuel non-adhesion location, the angle moved to the high temperature portion is set as the rotation angle.

  As a result, in the internal combustion engine of the first embodiment, the sprayed fuel comes into contact with the relatively high temperature portion of the umbrella portion of the intake valve 31, so that the vaporization of the fuel in contact with the high temperature portion is promoted, and the umbrella The adhesion of the liquid fuel to the part can be reduced. Therefore, in this internal combustion engine, the fuel vaporized by hitting the umbrella portion can be mixed with air and sent into the combustion chamber CC. Therefore, the actual air-fuel ratio of the air-fuel mixture formed in the combustion chamber CC is calculated as the required air-fuel ratio. Can be approached. For this reason, this internal combustion engine does not require correction to the required air-fuel ratio, or the correction amount is reduced, so that air-fuel ratio controllability is improved and good combustion control according to operating conditions can be executed. become able to.

  By the way, although not shown, the valve rotating means 32 described above is formed in a spiral groove formed on the outer peripheral surface of the valve stem of the intake valve 31, and on the outer peripheral surface of the valve stem in communication with the spiral groove. An axial groove and a cylindrical body having protrusions formed on the inner peripheral surface facing the outer peripheral surface of the valve stem can be configured. When the intake valve 31 is raised (or lowered), the valve rotating means 32 rotates the cylindrical protrusion along the spiral groove at the predetermined rotation angle so that the intake valve 31 is lowered (or raised). ) Is set so that the protrusion does not rotate along the axial groove. This eliminates the need for control by the electronic control unit 1 or an electric motor, and thus simplifies the system while reducing the adhesion of liquid fuel to the umbrella portion of the intake valve 31.

  Here, the intake valve 31 may be rotated at least once every intake stroke on the assumption that the temperature distribution is uneven under many circumstances. Depending on the in-cylinder pressure, the temperature distribution is uniform, and there may be a situation where it is not necessary to rotate the cylinder. For this reason, it is preferable to rotate the intake valve 31 after knowing its temperature distribution. Therefore, in the first embodiment, valve temperature measuring means for measuring the temperature distribution of the umbrella portion of the intake valve 31 or valve temperature estimating means for estimating the temperature distribution is provided. The valve temperature measuring means and the valve temperature estimating means are provided as a function of the electronic control device 1.

For example, as shown in FIG. 2, the valve temperature measuring means is measured from detection signals of temperature sensors 73 such as a plurality of thermocouples embedded in the umbrella portion 31a of the intake valve 31 at equal intervals in the circumferential direction. Here, divided into four and the umbrella portions 31a at the circumferential direction, respectively to embed the temperature sensor 73 on the four cells 31a ₁ ~31a _4.

Also, the valve temperature estimation means, for example, obtains the temperature of each cell 31a ₁ ~31a ₄ from heat balance of its respective cell 31a ₁ ~31a _4, thereby estimate the temperature distribution of the umbrella portion 31a.

Specifically, the valve temperature estimating means calculates the initial temperature Tv of each of the cells 31a _{1 to} 31a ₄ as shown in the flowchart of FIG. 3 immediately after the engine is started or after the electronic control unit 1 detects the ignition ON signal. (Step ST1). Since the intake valve 31 and the cylinder head 11 at that time can be estimated to have the same temperature as that of the cooling water, the valve temperature estimation means obtains the cooling water temperature Tw from the detection signal of the water temperature sensor 72 and obtains this. It is set as the initial temperature Tv of each of the cells 31a _{1 to} 31a ₄ .

  Subsequently, the valve temperature estimating means acquires various state quantities used in the subsequent process (step ST2). As the state quantity, the rotation angle of the crankshaft 15, the rotation angle of the intake camshaft, and the like are acquired.

  Then, the valve temperature estimating means determines whether the intake valve 31 is in an open state or a closed state by using information on the rotation angle of the crankshaft 15 and the rotation angle of the intake camshaft (step) ST3).

  Here, if the intake valve 31 is in the open state, the valve temperature estimating means determines the gas flow direction in the vicinity of the intake valve 31 (particularly, the umbrella portion 31a) (step ST4). The gas is roughly classified into air (air mixture) sucked into the combustion chamber CC and in-cylinder gas (combustion gas) flowing backward from the combustion chamber CC. Therefore, this valve temperature estimating means forwards the gas flow direction in the forward flow direction when it is determined other than the valve overlap period during the intake stroke based on, for example, the rotation angle of the crankshaft 15 or the rotation angle of the intake side camshaft ( In the case of a valve overlap period during the intake stroke, the flow direction of the gas is determined to be the backflow of the in-cylinder gas.

When the valve temperature estimating means determines “forward flow” in step ST4, the valve temperature estimation means obtains heat transfer with the forward flow gas (air, mixture) on the intake port 11b side surface of each of the cells 31a _{1 to} 31a ₄ ( Step ST5). In this case, the valve temperature estimation means supplies the respective cells 31a ₁ to 31a ₄ based on the temperature Tg of the forward flow gas, the pressure of the forward flow gas, the flow velocity of the forward flow gas, the heat transfer coefficient of the forward flow gas, and the like. The input / output energy from the forward flow gas (air, mixture) is calculated. As the temperature Tg of the forward flow gas, for example, information such as the outside air temperature can be used. Further, as the pressure of the forward flow gas, information on the internal pressure of the intake port 11b or the like can be used. Further, the flow velocity of the forward flow gas can be obtained by using information on the engine speed, the intake air amount, and the opening / closing timing of the intake valve 31. If it is determined in step ST4 that “backflow”, the heat transfer with the backflow gas (in-cylinder gas) on the intake port 11b side surface of each of the cells 31a _{1 to} 31a ₄ is similarly obtained ( Step ST12).

Further, the valve temperature estimating means, in a manner similar to this heat transfer with the cylinder interior gas of the combustion chamber CC side surface of each of the cells 31a ₁ ~31a _4, i.e., the cylinder of the cell 31a ₁ ~31a ₄ each Input / output energy from the internal gas is obtained (step ST6).

Further, the valve temperature estimating means obtains the latent heat of vaporization when the fuel in each of the cells 31a _{1 to} 31a ₄ evaporates (step ST7), and between the adjacent cells in each of the cells 31a _{1 to} 31a ₄ Is determined (step ST8).

Then, the valve temperature estimating means calculates the heat balance of each of the cells 31a _{1 to} 31a ₄ based on the heat transfer and the latent heat of vaporization (step ST9), and updates each temperature Tv (step ST10).

  This valve temperature estimation means determines whether or not the engine is stopped (step ST11). If it is stopped, the present processing operation is terminated, and if it is not stopped, the process returns to step ST2.

On the other hand, if the determination that the "closing" is made in step ST3 described above, the valve temperature estimation means, gas (air in the intake port 11b of the intake port 11b side surface of each of the cells 31a ₁ ~31a _4, mixed Heat transfer with the valve seat contact surface in each of the cells 31a _{1 to} 31a ₄ (step ST14). And it progresses to said step ST6.

This valve temperature estimation means repeats the above operation to estimate the temperatures of the cells 31a _{1 to} 31a ₄ .

  Hereinafter, the processing operation by the electronic control unit 1 for the internal combustion engine of the first embodiment will be described based on the flowchart of FIG.

First, the electronic control unit 1 according to the first embodiment measures or estimates the temperature distribution of the umbrella portion 31a of the intake valve 31 by the above-described valve temperature measuring means or valve temperature estimating means (step ST20), and the temperature distribution is It is determined whether or not they are equal (that is, whether or not there is a temperature difference between the cells 31a _{1 to} 31a ₄ ) (step ST25).

  Here, when the electronic control unit 1 determines that the temperature distribution is uneven, the electronic control device 1 uses the information on the rotation angle of the crankshaft 15 and the rotation angle of the intake camshaft to determine whether the intake valve 31 is open. It is determined whether or not the valve is closed (step ST30).

  If the intake valve 31 is in the open state, the electronic control unit 1 drives and controls the valve rotation means 32 to rotate the intake valve 31 to the predetermined rotation angle (step ST35). As a result, the relatively high temperature portion of the umbrella portion 31a of the intake valve 31 is moved to the fuel flow path, so that the liquid fuel adheres to the umbrella portion 31a as described above. be able to. Therefore, in this internal combustion engine, the air-fuel ratio controllability is improved and it becomes easy to form a mixture of the required air-fuel ratio, so that it is possible to execute good combustion control according to the operating conditions.

  On the other hand, when the electronic control unit 1 determines that the temperature distribution is uniform in step ST25 or determines that the intake valve 31 is in the closed state in step ST30, the electronic control device 1 ends this processing operation. Then, the process returns to step ST20. As a result, unnecessary rotating operation of the intake valve 31 is avoided, so that it is not necessary to supply power to the electric motor or the like of the valve rotating means 32, and power consumption can be reduced.

  As described above, according to the internal combustion engine of the first embodiment, the adhesion of liquid fuel to the umbrella portion 31a of the intake valve 31 is reduced, so that good combustion control by the required air-fuel ratio according to the operating conditions is performed. Can be executed.

  In the above example, the rotation angle of the intake valve 31 is set to a predetermined value. However, the rotation angle may be set each time based on the measured or estimated temperature distribution of the intake valve 31. That is, in this internal combustion engine, the relative high temperature part can be determined from the temperature distribution, and therefore, a rotation angle at which the high temperature part can be moved to the fuel flow path is calculated, and electronic control is performed at the rotation angle It is preferable that the device 1 controls the valve rotation means 32 to be driven. As a result, the sprayed fuel can be accurately applied to the high temperature portion of the intake valve 31, so that the fuel can be more reliably vaporized and the liquid fuel can be prevented from adhering.

  Next, a second embodiment of the internal combustion engine according to the present invention will be described with reference to FIGS.

  In the first embodiment described above, the intake valve 31 is set to rotate when the intake valve 31 is open. However, even in such a valve-open state, after fuel injection, the sprayed fuel also hits the low temperature portion of the intake valve 31, so that the fuel cannot be vaporized effectively at the low temperature portion. The amount of liquid fuel deposited cannot be reduced.

  Therefore, in the second embodiment, the driving state of the fuel injection device 41 (in other words, whether or not the fuel is injected in the intake stroke in one cycle) is determined, and the fuel injection is started. The electronic control device 1 is set so that the rotation of the intake valve 31 is executed before. With regard to such a drive state, for example, whether or not the electronic control device 1 has issued an injection start command to the fuel injection device 41, or is the crank angle before the fuel injection start timing according to the injection start command? It can be judged from whether or not.

  Specifically, the electronic control device 1 according to the second embodiment performs a processing operation as shown in the flowchart of FIG. In the second embodiment as well, first, after measuring or estimating the temperature distribution of the umbrella portion 31a of the intake valve 31 (step ST20), the temperature distribution state determination process (step ST25), and then the intake valve 31 is executed (step ST30). Since the processing operations of these steps ST20 to ST30 are performed in the same manner as in the first embodiment, the description thereof is omitted here.

  When it is determined in step ST30 that the intake valve 31 is in the open state, the electronic control unit 1 according to the second embodiment determines whether or not it is before the start of fuel injection (step ST32).

  Here, if the fuel injection is started or during the injection, the electronic control unit 1 ends the present processing operation once and returns to step ST20. As a result, unnecessary rotating operation of the intake valve 31 is avoided, so that it is not necessary to supply power to the electric motor or the like of the valve rotating means 32, and power consumption can be reduced.

  On the other hand, if it is determined in step ST32 that fuel injection has not started, the electronic control unit 1 moves the intake valve 31 to a predetermined rotational angle or a temperature distribution in the same manner as in the first embodiment. The rotation is rotated to the corresponding set rotation angle (step ST35), and the fuel is injected from the fuel injection device 41 after the rotation is completed (step ST37). As a result, the sprayed fuel from the fuel injection device 41 reliably hits the high-temperature portion of the intake valve 31, so that the attachment of liquid fuel to the umbrella portion 31a can be reliably reduced.

  Therefore, according to the internal combustion engine of the second embodiment as described above, a more accurate mixture of the required air-fuel ratio can be formed, so that good combustion control corresponding to the operating conditions can be executed.

  Next, a third embodiment of the internal combustion engine according to the present invention will be described with reference to FIGS.

  In the above-described second embodiment, the rotation operation of the intake valve 31 is terminated before fuel injection, and the sprayed fuel is reliably applied to the high temperature portion. However, for example, there are cases where the spray angle of the fuel is narrow and the sprayed fuel only hits the umbrella portion 31a only locally. In such a case, there is a possibility that the portion not exposed to the fuel is also in a high temperature state. However, it is inefficient not to vaporize the fuel in spite of high fuel efficiency, and there is a possibility that the fuel cannot be completely vaporized if the fuel injection amount is large.

  Therefore, in the third embodiment, the intake valve 31 is configured to rotate at least once during the fuel injection period. Whether or not it is during the fuel injection period can be determined from, for example, an injection command to the fuel injection device 41 by the electronic control unit 1 or a crank angle during the fuel injection period according to the injection command. it can.

  Here, the number of rotations of the intake valve 31 is determined according to operating conditions. For example, the fuel injection amount may be set to be large depending on the operating conditions. Therefore, if the fuel injection amount is large, the intake valve 31 is rotated a plurality of times, thereby improving the vaporization efficiency while maintaining the high temperature state of the umbrella portion 31a. It is preferable to make it.

  Specifically, the electronic control device 1 according to the third embodiment performs a processing operation as shown in the flowchart of FIG. Also in the third embodiment, first, after measuring or estimating the temperature distribution of the umbrella portion 31a of the intake valve 31 (step ST20), the temperature distribution state determination process (step ST25), and then the intake valve 31 is executed (step ST30). Since the processing operations of these steps ST20 to ST30 are executed in the same manner as in the first and second embodiments, the description thereof is omitted here.

  When the electronic control device 1 of the third embodiment determines that the intake valve 31 is in the open state in step ST30, the electronic control device 1 determines whether or not it is during the fuel injection period (step ST33).

  Here, if it is not during the fuel injection period, the electronic control unit 1 ends the present processing operation once and returns to step ST20. As a result, unnecessary rotating operation of the intake valve 31 is avoided, so that it is not necessary to supply power to the electric motor or the like of the valve rotating means 32, and power consumption can be reduced.

  On the other hand, when it is determined in step ST33 that the fuel injection period is in progress, the electronic control unit 1 obtains the angular velocity of the intake valve 31 according to the operating conditions, and the valve rotating means 32 so as to obtain this angular velocity. And the intake valve 31 is rotated during the fuel injection period (step ST35). As a result, the sprayed fuel comes into contact with the entire umbrella portion 31a of the intake valve 31, and the temperature drop due to local latent heat of vaporization is suppressed, so that the temperature of the entire umbrella portion 31a can be kept uniform while maintaining a high temperature state. The sprayed fuel is easily vaporized by using more high temperature portions, and the adhesion of the liquid fuel to the umbrella portion 31a can be efficiently reduced.

  Therefore, according to the above-described internal combustion engine of the third embodiment, it is possible to execute good combustion control with an air-fuel mixture having an exact required air-fuel ratio corresponding to the operating conditions.

  By the way, in the internal combustion engine of the third embodiment, as in the first and second embodiments, the rotational operation of the intake valve 31 is performed according to whether or not the temperature distribution of the umbrella portion 31a of the intake valve 31 is uniform. The necessity of execution is determined. However, in this internal combustion engine, since the intake valve 31 is configured to rotate at least once during the fuel injection period, the temperature distribution of the umbrella portion 31a becomes uniform by performing the rotation operation. Therefore, in the third embodiment, the processing operations of steps ST20 and ST25 related to the temperature distribution are not necessarily performed.

  On the other hand, in this internal combustion engine, the sprayed fuel is also applied to the low temperature portion of the umbrella portion 31a by rotating the intake valve 31 at least once during the fuel injection period. Depending on the requirements, it takes time for the low temperature portion to rise in temperature, and fuel vaporization in the low temperature portion may be delayed. For this reason, at least until the temperature distribution of the umbrella portion 31a becomes uniform, the rotation operation may be controlled so that only the high temperature portion is positioned on the fuel flow path based on the measured or estimated temperature distribution. The electronic control device 1 may be caused to perform only such a rotation operation.

  Here, in each of the first to third embodiments described above, the adhesion of the liquid fuel was reduced only by the fuel vaporizing action at the high temperature portion of the intake valve 31, but in order to reduce the adhesion of the liquid fuel, In addition to this, or alternatively, the centrifugal force accompanying the rotation of the intake valve 31 may be used. In such a case, an angular velocity at which the attached fuel can be shaken off from the intake valve 31 (particularly, the umbrella portion 31a) is determined in advance, and the intake air is sucked at this angular velocity at any of the rotation times of the first to third embodiments. The electronic control unit 1 is set so that the valve 31 is continuously rotated. Thereby, when using this structure independently, there can exist the same effect of said each Examples 1-3, Moreover, when using this structure and the structure of each said Examples 1-3 together Therefore, the adhesion of the liquid fuel is more reliably reduced than in the first to third embodiments. The angular velocity may be set according to operating conditions. For example, since the fuel injection amount varies depending on the operating conditions as described above, the angular velocity is set large so that a large centrifugal force is applied if the fuel injection amount is large, and small if a small centrifugal force is sufficient if the fuel injection amount is small. Can be set.

  Further, in each of the first to third embodiments described above, the port injection type internal combustion engine is used as an example. However, the various configurations related to the valve rotation unit 32 described above include in-cylinder direct injection type internal combustion engine and port injection. The present invention is also applicable to an internal combustion engine that uses in-cylinder direct injection together. In the case of the in-cylinder direct injection internal combustion engine, if there is an intake valve 31 on the flow path of the fuel directly injected into the cylinder, the port injection and in-cylinder direct injection are performed. In the case of the internal combustion engine to be used in combination, if the intake valve 31 exists on the flow path of each sprayed fuel, the same effect as in the case of the port injection type internal combustion engine described above can be obtained.

  As described above, the internal combustion engine according to the present invention is useful for a technique for reducing the amount of fuel spray adhering to the intake valve and improving the controllability of the air-fuel mixture to the required air-fuel ratio.

It is a figure which shows the structure of the internal combustion engine which concerns on this invention. It is the top view which looked at an example of the intake valve concerning the present invention from the valve stem side. It is a flowchart explaining the estimation operation | movement of the temperature distribution of an intake valve. 3 is a flowchart illustrating a control operation of the internal combustion engine according to the first embodiment. 7 is a flowchart illustrating a control operation of the internal combustion engine of the second embodiment. 7 is a flowchart illustrating a control operation of the internal combustion engine of the third embodiment.

Explanation of symbols

1 Electronic Control Unit 11b Intake Port 31 Intake Valve 31a Umbrella 31a _{1 to} 31a ₄ Cell 32 Valve Rotating Means 41 Fuel Injection Device CC Combustion Chamber

Claims (2)

An internal combustion engine comprising: a fuel injection device that injects fuel into an intake port or / and a combustion chamber; and an intake valve that is disposed on or moves along a flow path of fuel injected from the fuel injection device In
A valve temperature measuring means for measuring the temperature distribution of the intake valve or a valve temperature estimating means for estimating the temperature distribution;
Valve rotation means for rotating the intake valve about the axis of the valve stem in order to move the high temperature portion of the intake valve on the flow path of fuel from the fuel injection device;
An internal combustion engine comprising:   The internal combustion engine according to claim 1, wherein the valve rotation means is configured to execute a rotation operation of the intake valve in accordance with a fuel injection timing of the fuel injection device.

Images