JP2010101176A - Spark-ignition internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems wherein, when plasma is generated in a combustion chamber from magnetron through a microwave, the microwave is leaked to the outside of the combustion chamber through an opened valve during a period when one of an intake valve and an exhaust valve is opened, and thereby an electronic control device controlling the operation of an internal combustion engine and the other electronic device mounted on an automobile are influenced. <P>SOLUTION: This spark-ignition internal combustion engine includes an intake system provided with an intake manifold communicating with an intake port and an exhaust system provided with an exhaust manifold communicating with an exhaust port, and ignites an air-fuel mixture by reacting the plasma generated in the combustion chamber by an electromagnetic wave with spark discharge with an ignition plug. A shutoff means shutting off the electromagnetic wave leaked from the inside of the combustion chamber is provided in at least the intake system. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a spark ignition internal combustion engine that generates plasma in a combustion chamber and ignites an air-fuel mixture by plasma and spark discharge by an ignition plug.

  2. Description of the Related Art Conventionally, in a spark ignition internal combustion engine mounted on a vehicle, particularly an automobile, an air-fuel mixture in a combustion chamber is ignited at each ignition timing by spark discharge between a center electrode and a ground electrode of a spark plug. In such ignition by an ignition plug, for example, in an internal combustion engine of a type in which fuel is directly injected into a cylinder, if the injected fuel is not distributed at the spark discharge position of the ignition plug, it rarely occurs.

For this reason, in such an internal combustion engine, a plasma atmosphere is generated in the discharge region of the spark plug, for example, as described in Patent Document 1, in order to compensate for the spark discharge of the spark plug, and an arc is generated in the plasma atmosphere. It is known that the discharge is performed to surely ignite the air-fuel mixture in the combustion chamber without applying a higher voltage than in the past and to obtain a stable flame.
JP 2007-32349 A

  By the way, as a method for generating plasma under atmospheric pressure, for example, a method using a magnetron is considered. In the case of using such a magnetron, there is a time delay until the magnetron operates after energization. This is due to the fact that the magnetron only operates after heating the cathode part.

  An intake valve and an exhaust valve are provided for the combustion chamber of the internal combustion engine. As described above, when plasma is generated from the magnetron by the microwave, the microwave leaks to the outside of the combustion chamber through the opened valve while either the intake valve or the exhaust valve is open. There is. For this reason, there are cases in which an electronic control device that controls the operation of the internal combustion engine or other electronic devices mounted on the automobile is affected.

  Therefore, the present invention aims to eliminate such problems.

  That is, the spark ignition internal combustion engine of the present invention includes an intake system including an intake manifold that communicates with an intake port and an exhaust system that includes an exhaust manifold that communicates with an exhaust port, and generates plasma and ignition generated in the combustion chamber by electromagnetic waves. A spark ignition type internal combustion engine that reacts with a spark discharge by a plug to ignite an air-fuel mixture, wherein at least an intake system is provided with a blocking means for blocking electromagnetic waves leaking from a combustion chamber.

  According to such a configuration, even when the combustion chamber and the intake port of the intake system are in communication with each other during the intake stroke, electromagnetic waves leaking from the combustion chamber are blocked in the intake system by the blocking means. . Therefore, by suppressing the electromagnetic wave leaking outside the combustion chamber through the intake port, it is possible to minimize the influence of the electromagnetic wave on the electronic device existing outside the internal combustion engine.

  In order to facilitate attachment work and maintenance, it is preferable that the blocking means is made of a mesh member provided between the intake port of the intake system and the intake manifold.

  The present invention is configured as described above and blocks electromagnetic waves leaking outside the combustion chamber via the intake port of the intake system, thereby minimizing the influence of electromagnetic waves on electronic devices existing outside the internal combustion engine. be able to.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  An engine 100 schematically showing the configuration of one cylinder in FIG. 1 is a three-cylinder for an automobile. The intake system 1 of the engine 100 includes an air cleaner 2, a throttle body 4 having a throttle valve 3 that controls the amount of intake air, an intake manifold 6 having a surge tank 5 for suppressing pulsation of intake air, and a cylinder head 7. The intake port 8 is formed, an intake valve 9 that opens and closes the intake port 8, and a mesh member 10 that is a blocking means provided between the intake port 8 and the intake manifold 6.

  The intake manifold 6 is made of heat-resistant synthetic resin and is attached to the cylinder head 7 via a gasket. In this case, the mesh member 10 is attached to a through hole provided in the gasket. That is, the gasket is sandwiched between the intake manifold 6 and the cylinder head 7 and attached as a sealing material, and has a through hole corresponding to the opening of each branch pipe of the intake manifold 6. In other words, the through hole corresponds to the opening on the intake side of the intake port 8 of the cylinder head 7. Therefore, if the mesh member 10 is attached to the through hole so as to be sandwiched between the intake manifold 6 and the cylinder head 7, the mesh member 10 can be easily attached when the intake manifold 6 is attached or detached.

  The mesh member 10 is created by knitting a highly conductive vertical wire and horizontal wire. The wire itself is preferably as thin as possible. In this case, the mesh shape is not particularly limited. The mesh size (mesh) is set according to the frequency of the microwave used. For example, when the frequency of the microwave is 2,45 GHz, the wavelength is about 12 cm. Therefore, the size is sufficiently smaller than this wavelength, for example, 30 mm or less which is 1/4 or less of the wavelength. By setting the mesh size in this way, there is no resistance against inflow of intake air.

  The size of the mesh is set in accordance with the frequency of the microwave, but when it is provided in the intake system 1, the size that does not become a resistance against the inhalation of air is also taken into consideration. In other words, basically, it is set based on the frequency of the microwave, in other words, the wavelength, and by selecting the maximum one that does not allow the microwave to pass through the mesh, the intake characteristics are not degraded. The size of the mesh is set.

The engine 100 further includes a fuel injection valve 11 that injects fuel toward the intake port 8. The fuel injection valve 11 is attached to the cylinder head 7 so that the fuel injected to the mesh member 10 does not adhere. An ignition plug 13 and an antenna 14 that radiates electromagnetic waves into the combustion chamber 12 are attached to the ceiling portion of the combustion chamber 12 formed in the cylinder head 7. In addition, in the exhaust system 18 including the exhaust port 15, the exhaust valve 16, and the exhaust manifold 17, the three-way catalyst 19 is connected to the exhaust manifold 17 so that the exhaust gas can flow in, and is upstream of the three-way catalyst 17. The O ₂ sensor 20 is attached to the position.

  An ignition coil 21 integrally provided with an igniter is detachably attached to the ignition plug 13 of each cylinder. The spark plug 13 applies a high voltage for spark discharge to the spark plug 13 when an ignition signal is input to the igniter. The ignition signal is output from the electronic control unit 22 that controls the operation of the engine 100. The fuel injection valve 11 may be attached so as to inject fuel directly into the combustion chamber 12.

  The antenna 14 is connected to a high voltage AC generator 25 that includes a magnetron 23 and a control circuit 24 that controls the magnetron 23. As the antenna 14, a horn type or monopole type can be used. In this embodiment, a horn type antenna 14 is used, and the microwave output from the magnetron 23 is applied to the antenna 14 by a waveguide. The control circuit 24 is configured to receive a high-voltage AC generation signal output from the electronic control unit 22. The control circuit 24 generates a microwave output from the magnetron 22 based on the input high-voltage AC generation signal. It controls output timing and output power. Note that when a monopole antenna is used, the microwave is supplied to the antenna via a waveguide and a coaxial cable.

  The electronic control unit 22 is mainly configured by a microcomputer system including a central processing unit 26, a storage device 27, an input interface 28, and an output interface 29. The central processing unit 22 executes various control programs stored in the storage device 27 to control the operation of the engine 100.

Information necessary for controlling the operation of the engine 100, which is output from various sensors such as the O ₂ sensor 20, is input to the central processing unit 26 via the input interface 28, and the central processing unit 26 Outputs a control signal to the fuel injection valve 11, the ignition coil 21, the high-pressure AC generator 25, and the like via the output interface 29. Various sensors for controlling the operation of engine 100 may be the same as those known in this field, and thus description thereof is omitted.

  In such a configuration, in the engine 100, in an operating state, the microwave generated by the high-voltage AC generator 25 is radiated from the antenna 14 into the combustion chamber 7, and the plasma generated thereby and the spark plug 13 The air-fuel mixture is ignited by reacting with spark discharge. When plasma is generated, a microwave is applied to the antenna 14, whereby a high-frequency electric field is formed in the combustion chamber 12 in a direction orthogonal to the spark discharge caused by the spark plug 13.

  At the time of ignition, a spark discharge is generated in the spark plug 13 by an ignition coil (not shown), and a high-frequency electric field is generated by microwaves almost simultaneously with or immediately after the spark discharge to generate plasma, thereby generating a combustion chamber 12. It is the structure which burns the inside air-fuel mixture rapidly.

  Specifically, the spark discharge by the spark plug 13 becomes plasma in a high-frequency electric field, and the flame becomes large.

  This is because the flow of electrons due to the spark discharge and the ions and radicals generated by the spark discharge oscillate and meander due to the influence of the high-frequency electric field, resulting in a longer path length and the number of collisions with surrounding water and nitrogen molecules. This is due to a dramatic increase. Water molecules and nitrogen molecules that have been struck by ions and radicals become OH radicals and N radicals, and the surrounding gas that has been struck by ions and radicals is ionized, in other words, a plasma state. The flame will increase dramatically.

  As a result, the air-fuel mixture is ignited by the spark discharge increased by reacting with the high-frequency electric field, so that the ignition region is expanded and the two-dimensional ignition of only the spark plug 13 is changed to the three-dimensional ignition. Accordingly, the initial combustion is stabilized, the combustion rapidly propagates into the combustion chamber 12 with the increase of the radicals described above, and the combustion expands at a high combustion rate.

  In the above, when the microwave radiated to generate plasma enters the intake port 8, the microwave passes through the intake port 8 and further proceeds to the intake manifold 6. However, since the mesh member 10 is attached to the opening on the attachment end side of the intake manifold 6 and the mesh of the mesh member 10 has an opening having a size shorter than the wavelength of the microwave, the microwave is caused by the mesh member 10. Blocked. That is, the microwave that has entered the intake port 8 does not travel upstream of the intake system 1 from the intake port 8.

  Therefore, the microwave can be prevented from leaking outside the engine 100. In this way, by suppressing leakage of microwaves, it is possible to prevent malfunctions of electromagnetic wave-sensitive components such as an igniter integrated ignition coil and various sensors such as a throttle valve opening sensor in an electronic throttle mechanism. be able to. Therefore, safety can be improved.

  In addition, this invention is not limited to the above-mentioned embodiment.

  In the above-described embodiment, the net-like member is formed by knitting a wire, but it may be formed by forming a number of through holes in a thin steel plate like punching metal. In this case, at the inlet side position of the intake port of the gasket, a plurality of through holes may be formed in the gasket material without opening an opening corresponding to the intake port, and a blocking means may be provided integrally with the gasket. In such a configuration, the through-hole is formed with a dimension shorter than the wavelength, as in the above-described embodiment. Further, the shape is a square, a polygon such as a pentagon or a hexagon, or a circle.

  In the above-described embodiment, the engine 100 in which the blocking means is provided in the intake system has been described. However, the engine 100 may also be provided in the exhaust system. In this case, the blocking means, that is, the mesh member, may be the same as that of the above-described embodiment, and the mounting position may be a portion of the gasket sandwiched between the cylinder head and the exhaust manifold. Even the shut-off means provided in the exhaust system may be formed integrally with the gasket as described above.

  In addition, in the above description, the configuration in which the blocking means is provided between the cylinder head 7 and the intake manifold 6 or the exhaust manifold 17 has been described. However, the intake port 8 and the exhaust port constituting the intake system 1 and the exhaust system 18 are described. 15 or inside the intake manifold 6 and the exhaust manifold 17.

  Further, the high-voltage AC generator may be a traveling wave tube or the like instead of the above-described magnetron, and may further include a semiconductor microwave oscillation circuit.

  In addition, although the beam type antenna has been described in the above-described embodiment, a monopole type antenna may be used.

  Furthermore, the center electrode of the spark plug 1 may function as an antenna to form a high-frequency power feeding unit. In this case, if the high frequency is continuously applied to the center electrode at a constant voltage, the temperature of the center electrode rises excessively, so the high frequency voltage is set to be lower than the upper limit temperature set based on the heat resistance temperature of the center electrode. It is something to control.

  In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  As an application example of the present invention, it can be used for a spark ignition type internal combustion engine that uses gasoline or liquefied natural gas as fuel and requires spark discharge by an ignition plug for ignition.

BRIEF DESCRIPTION OF THE DRAWINGS Structure explanatory drawing which shows schematic structure of embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Intake system 6 ... Intake manifold 8 ... Intake port 10 ... Reticulated member 12 ... Combustion chamber 15 ... Exhaust port 17 ... Exhaust manifold 18 ... Exhaust system

Claims (2)

It has an intake system that includes an intake manifold that communicates with the intake port and an exhaust system that includes an exhaust manifold that communicates with the exhaust port. A spark ignition internal combustion engine that ignites,
A spark ignition type internal combustion engine in which at least an intake system is provided with blocking means for blocking electromagnetic waves leaking from a combustion chamber.   2. The spark ignition internal combustion engine according to claim 1, wherein the shut-off means comprises a mesh member provided between the intake port of the intake system and the intake manifold.

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