JP2006242039A - Laser ignition device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser ignition device for an internal combustion engine capable of improving emission and fuel consumption by positively detecting abnormality of a laser beam generating means for generating laser beams. <P>SOLUTION: The laser ignition device for the internal combustion engine is provided with a laser beam output control part 101 for performing output control of ignition signals; a laser beam generating part 61 for generating laser beams based on the ignition signals; a laser beam irradiation part 63 for irradiating an air-fuel mixture in a combustion chamber 20 of the internal combustion engine with laser beams to activate the air-fuel mixture; a laser beam detecting part 64 for detecting laser beams generated by the laser beam generating part 61; and an abnormality detecting part 65 for detecting abnormality of the laser beam generating part 61 based on the detected laser beams and ignition signals. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a laser ignition device for an internal combustion engine.

As an internal combustion engine ignition device, for example, Patent Document 1 discloses a laser ignition device for an internal combustion engine using laser light. The internal combustion engine laser ignition device is a device that condenses laser light emitted from a laser oscillator in a combustion chamber of the internal combustion engine by a lens and activates an air-fuel mixture in the combustion chamber to ignite and burn.
JP-A-5-33755

  However, when the internal combustion engine ignition device for generating and irradiating the laser beam is in an abnormal state, since there is no means for detecting the abnormality, the engine state becomes unstable, resulting in a deterioration in emissions and fuel consumption due to misfire and the like. May cause.

  The present invention has been made in view of such circumstances, and for an internal combustion engine that can improve emission and fuel consumption by reliably detecting an abnormality in a laser beam generating means that generates laser beams. An object is to provide a laser ignition device.

Means for Solving the Problems and Effects of the Invention

  An internal combustion engine laser ignition device according to the present invention includes an ignition signal output control means for controlling the output of an ignition signal, a laser light generating means for generating laser light based on the ignition signal, and the laser light in a combustion chamber of the internal combustion engine. Laser light irradiation means for irradiating the air-fuel mixture to activate the air-fuel mixture, laser light detection means for detecting the laser light generated by the laser light generation means, the detected laser light and the ignition signal And an abnormality detecting means for detecting an abnormality of the laser light generating means.

  That is, according to the laser ignition device for an internal combustion engine of the present invention, the laser light generating means is reliably in an abnormal state by comparing the laser light generated from the laser light generating means with the ignition signal that is the basis thereof. It can be determined whether or not. And when it determines with it being abnormal, an appropriate process can be performed according to an abnormal condition. In other words, it is possible to take a workaround so that the engine does not become unstable. As a result, even when the laser beam generating means is abnormal, it is possible to avoid deterioration of emissions such as misfire and deterioration of fuel consumption.

  The laser beam generation means includes a half mirror disposed in a passage path of the laser beam generated by the laser beam generation unit and inclined with respect to a traveling direction of the laser beam, and the laser beam irradiation unit includes the laser beam Either one of transmitted light that passes through the half mirror and reflected light that reflects from the half mirror is irradiated into the combustion chamber, and the laser light detection means detects the other of the transmitted light and the reflected light. May be.

  That is, the laser light detection means detects the laser light generated by the laser light generation means using the transmitted light and reflected light of the half mirror that is not irradiated to the combustion chamber. Therefore, since the laser beam generated by the laser beam generating unit can be reliably detected, it can be reliably determined whether or not the laser beam generating unit is abnormal.

  Further, the abnormality detection means may detect the abnormality by comparing the detected light emission energy intensity of the laser light and the light emission energy intensity of the ignition signal. In addition, the abnormality detection unit may detect the abnormality by comparing the detected light emission timing of the laser light and the light emission timing of the ignition signal.

  Here, as described above, the laser light generating means generates the laser light based on the ignition signal. The ignition signal includes information on the emission energy intensity of the laser beam and the emission timing of the laser beam. Therefore, when the laser beam generating means is normal, the emission energy intensity of the generated laser beam is the emission energy intensity corresponding to the emission energy intensity of the ignition signal. Further, when the laser beam generating means is normal, the emission timing of the generated laser beam is a timing according to the emission timing of the ignition signal. However, when the laser light generating means is abnormal, the emitted energy intensity of the generated laser light may become an emitted energy intensity that is unrelated to the emitted energy intensity of the ignition signal. Further, when the laser light generating means is abnormal, the light emission timing of the generated laser light may be a timing unrelated to the light emission timing of the ignition signal. That is, it is possible to reliably detect whether the laser light generating means is abnormal by comparing the light emission energy intensity and / or light emission timing of the laser light with the light emission energy intensity and / or the light emission timing of the ignition signal. Can do.

  The laser ignition device for an internal combustion engine includes an in-cylinder pressure detection unit that detects an in-cylinder pressure in a combustion chamber of the internal combustion engine, and a combustion analysis unit that performs a combustion analysis based on the in-cylinder pressure, and the abnormality detection unit includes: The abnormality may be detected based on an analysis result by the combustion analysis means and the ignition signal. Thus, by providing the in-cylinder pressure detecting means and the combustion analyzing means, it is possible to reliably detect whether or not the laser light generating means is abnormal even when the laser light detecting means is abnormal. . Of course, when the laser light detection means is normal, the abnormality determination can be performed twice, so that the accuracy of the abnormality determination result can be further improved.

  Further, it is preferable to provide an abnormality processing means for restricting at least one of the fuel injection amount and the intake air amount when the abnormality detection means detects the abnormality. When it is determined that the laser light generating means is abnormal, it may be difficult to perform appropriate laser light irradiation. Therefore, abnormal combustion in the combustion chamber can be prevented by limiting the fuel injection amount or the intake air amount. In addition, when it is determined that the laser light generating means is abnormal, it is preferable to display the fact that the laser light is abnormal and transmit it to the driver.

  The internal combustion engine laser ignition device includes an ignition device of a system different from the laser light generation means, and an ignition system switching for igniting the air-fuel mixture by the ignition device when the abnormality detection means detects the abnormality. Means. Here, the ignition device is, for example, a laser ignition device including an ignition plug and other laser generating means. When it is determined that the laser light generating means is abnormal, the air-fuel mixture cannot be properly burned using the laser light generating means. Therefore, the air-fuel mixture can be appropriately burned by switching to another ignition device by the ignition system switching means.

  Next, the present invention will be described in more detail with reference to embodiments.

(1) Configuration of in-cylinder direct injection internal combustion engine A direct injection internal combustion engine to which the laser ignition device for an internal combustion engine of the present invention is applied will be described. An in-cylinder direct injection internal combustion engine (hereinafter referred to as “engine”) in the present embodiment will be described with reference to FIG. FIG. 1 is a diagram showing the configuration of the engine of the present embodiment.

  As shown in FIG. 1, the engine includes a cylinder block 1, a cylinder head 2, an intake valve 3, an exhaust valve 4, a fuel injection valve 5, a laser ignition device 6, a piston 7, and an in-cylinder pressure detection sensor. 8, a crank angle detection sensor 9, and a control unit (ECU) 10. The combustion chamber 20 of the engine is defined by the inner peripheral wall of the cylinder block 1, the top surface of the piston 7, and the ceiling inner wall of the cylinder head 2.

  The cylinder head 2 is connected to an intake pipe 2a that is connected to an intake pipe that forms a passage through which intake air flows, and an exhaust port 2b that is connected to an exhaust pipe that forms a passage through which combustion gas and the like are connected to discharge exhaust gas. It has. An intake valve 3 is arranged to be openable and closable at the intake port 2a, and an exhaust valve 4 is arranged to be openable and closable at the exhaust port 2b. That is, the intake valve 3 blocks and allows the flow of intake air introduced from the intake pipe to the intake port 2a into the combustion chamber 20. The exhaust valve 4 blocks and allows the flow of the combustion gas generated in the combustion chamber 20 to the exhaust port 2b.

  The fuel injection valve 5 is provided in the cylinder head 2 and directly injects fuel into the combustion chamber 20. Specifically, the fuel injection valve 5 injects and supplies fuel toward a cavity formed in the top surface of the piston 7 in the combustion chamber 20.

  The laser ignition device 6 is provided in the cylinder head 2. Specifically, the laser ignition device 6 is disposed between the intake valve 3 and the exhaust valve 4. The irradiation port of the laser ignition device 6 is disposed so as to protrude into the combustion chamber 20. The laser igniter 6 radiates laser light from an irradiation port, and radiates heat energy to a region to be irradiated according to the wide angle or narrow angle where the light diverges. Specifically, the laser beam irradiation device 6 includes a laser beam generation unit 61, a half mirror 62, a laser beam irradiation unit 63, a laser beam detection unit 64, and an abnormality detection unit 65.

  The laser light generator 61 generates laser light based on an ignition signal output from a laser light output controller 81 of the ECU 10 described later. Specifically, the laser light generator 61 generates laser light according to the generation timing and generated energy intensity included in the ignition signal. The half mirror 62 is disposed in the path of the laser beam generated from the laser beam generator 61. Specifically, the half mirror 62 is disposed to be inclined with respect to the traveling direction of the laser light. The half mirror 62 transmits part of the laser light generated from the laser light generator 61 and reflects the rest of the laser light.

  The laser light irradiation unit 63 irradiates the combustion chamber 20 with laser light (transmitted light) that has passed through the half mirror 62. The laser light irradiation unit 63 is configured so that the focal position of the laser light to be irradiated is in the combustion chamber 20.

  The laser light detector 64 receives the laser light (reflected light) reflected from the half mirror 62 and detects the laser light. The laser light detection unit 64 detects the time when the reflected light is input and the energy intensity of the reflected light.

  The abnormality detection unit 65 inputs the input timing of the reflected light detected by the laser light detection unit 64 and the energy intensity of the reflected light. Furthermore, the abnormality detection unit 65 receives an ignition signal output from a laser light output control unit 81 of the ECU 10 described later. As described above, the ignition signal includes the generation timing of the laser beam and the generated energy intensity. Then, the abnormality detection unit 65 compares the input timing of the reflected light detected by the laser light detection unit 64 with the generation timing included in the ignition signal, and determines whether or not it is within a predetermined allowable range. To do. And when both are not contained in the predetermined allowable range, it determines with the laser beam generation part 61 being abnormal.

  Further, the abnormality detection unit 65 compares the energy intensity of the reflected light detected by the laser light detection unit 64 with the generated energy intensity included in the ignition signal, and determines whether or not both are in a predetermined correspondence relationship. To do. Here, the reflected light detected by the laser light detector 64 is a part of the laser light generated by the laser light generator 61. Therefore, the energy intensity of the reflected light is lower than the energy intensity of the laser beam generated by the laser beam generator 61. That is, when the energy intensity of the laser beam generated by the laser beam generator 61 is equivalent to the energy intensity of the ignition signal, the energy intensity of the reflected light is lower than the energy intensity of the ignition signal. Therefore, the relationship between the energy intensity of the reflected light and the generated energy intensity of the ignition signal when the laser light generator 61 is normal is stored in advance. Then, the abnormality detection unit 65 determines whether or not the energy intensity of the reflected light is included within the allowable range of the energy intensity corresponding to the generated energy of the ignition signal. Then, when the energy intensity of the reflected light is not included within the allowable range of the corresponding energy intensity, it is determined that the laser light generation unit 61 is abnormal.

  If the abnormality detection unit 65 determines that the laser light generation unit 61 is abnormal, the abnormality detection unit 65 outputs abnormality information to a fuel injection valve / intake / exhaust valve control unit 103 of the ECU 10 described later.

  The in-cylinder pressure detection sensor 8 is a sensor that detects the pressure (in-cylinder pressure) in the combustion chamber 20 (in-cylinder). That is, the in-cylinder pressure detection sensor 8 detects the pressure in the combustion chamber 20 that changes as the air-fuel mixture in the combustion chamber 20 ignites and burns. The crank angle detection sensor 9 is a sensor that detects the rotation angle of a crankshaft (not shown).

  The control device 10 includes a laser light output control unit (ignition signal output control means) 101, a combustion analysis unit 102, and a fuel injection valve / intake exhaust valve control unit 103. The laser light output control unit 101 generates an ignition signal and outputs it to the laser light generation unit 61. Here, as described above, the ignition signal includes information on the generation timing of the laser beam and the generated energy intensity of the laser beam. The generation timing of the laser beam is a timing at which the laser beam is irradiated into the combustion chamber 20. The generated energy intensity of the laser beam is the energy intensity of the laser beam irradiated into the combustion chamber 20.

  The laser beam output control unit 101 controls the generation timing and the generated energy intensity of the laser beam based on the crank angle signal output from the crank angle detection sensor 9. Further, the laser beam output control unit 101 inputs an analysis result of a combustion analysis unit 102 described later. The laser beam output control unit 101 controls the generation timing and the generated energy intensity of the laser beam in consideration of the analysis result in addition to the crank angle signal.

  The laser light output control unit 101 also outputs the generation timing and generated energy intensity of the laser light to the abnormality detection unit 65. Note that the abnormality detection unit 65 determines the abnormality of the laser light generation unit 61 using the generation timing and generated energy intensity of the laser light output from the laser light output control unit 101 as described above.

  The combustion analyzer 102 is based on the in-cylinder pressure detected by the in-cylinder pressure detection sensor 8, the crank angle detected by the crank angle sensor 9, and the ignition signal output from the laser light output controller 101. Perform combustion analysis at. Then, the result of the combustion analysis is output to the laser light output control unit 101. Further, the combustion analysis unit 102 can determine whether or not the laser light generation unit 61 is abnormal based on the result of the combustion analysis. When it is determined that the laser light generation unit 61 is abnormal, the combustion analysis unit 102 outputs abnormality information of the laser light generation unit 61 to the fuel injection valve / intake exhaust valve control unit 103.

  The fuel injection valve / intake exhaust valve control unit 103 controls the fuel injection valve 5, the intake valve 3, and the exhaust valve 4. Further, the fuel injection valve / intake / exhaust valve control unit 103 reduces the fuel injection amount injected by the fuel injection valve 5 when the abnormality information of the laser light generation unit 61 is input from the abnormality detection unit 65. Control. Further, when the abnormality information is input, the fuel injection valve / intake / exhaust valve control unit 103 reduces the opening of the intake valve 3 to limit the intake air amount. The fuel injection valve / intake / exhaust valve control unit 103 similarly limits the fuel injection amount and the intake air amount when the abnormality information of the laser light generation unit 61 is input from the combustion analysis unit 102.

  Next, the operation of the engine configured as described above will be described. First, when the intake valve 3 is opened, intake air is introduced into the combustion chamber 20 through the intake port 2a. Further, fuel is injected and supplied from the fuel injection valve 5 toward the cavity formed in the piston 7 in the combustion chamber 20.

  At this time, the laser beam output controller 101 of the ECU 10 outputs an ignition signal to the laser beam generator 61 of the laser ignition device 6. Then, the laser light generation unit 61 generates laser light, and the laser light transmitted through the half mirror 62 is irradiated into the combustion chamber 20 from the irradiation port of the laser light irradiation unit 63. As a result, the combustible air-fuel mixture composed of the intake air introduced into the combustion chamber 20 and the fuel injected and supplied from the fuel injection valve 5 is activated and ignited and combusted. Then, the piston 7 reciprocates, and the crankshaft that is the output shaft of the engine rotates. The combustion gas after combustion is exhausted from the combustion chamber 20 to the exhaust port 2b when the exhaust valve 4 is opened.

  When the laser beam generator 61 generates laser light, the laser beam detector 64 detects the laser beam reflected by the half mirror 62. Then, in the abnormality detection unit 65, the laser beam generation unit 61 is abnormal by comparing the laser beam detected by the laser beam detection unit 64 with the ignition signal output from the laser beam output control unit 101 as described above. It is determined whether or not. Thereby, it can be reliably determined whether or not the laser beam generation unit 61 is abnormal.

  When it is determined that the laser beam generator 61 is abnormal, the abnormality detector 65 outputs an abnormal signal to the fuel injection valve / intake / exhaust valve control unit 103 to control the fuel injection valve / intake / exhaust valve. The unit 103 limits the fuel injection amount and the intake air amount. As a result, abnormal combustion in the combustion chamber 20 can be prevented when the laser light generator 61 is abnormal.

  When the combustion analysis unit 102 determines that the laser light generation unit 61 is abnormal as a result of the combustion analysis, the combustion analysis unit 102 outputs an abnormal signal to the fuel injection valve / intake exhaust valve control unit 103. Thus, the fuel injection valve / intake / exhaust valve control unit 103 limits the fuel injection amount and the intake air amount. As a result, abnormal combustion in the combustion chamber 20 can be prevented when the laser light generator 61 is abnormal. In addition, abnormality detection can be performed more reliably by performing abnormality detection by the abnormality detection unit 65 and abnormality detection by the combustion analysis unit 102 in duplicate. Furthermore, even if either one of the abnormality detection unit 65 or the combustion analysis unit 102 fails, the other can detect the abnormality of the laser light generation unit 61.

  In the embodiment described above, the fuel injection amount and the intake air amount are limited when the laser light generation unit 61 is abnormal. However, the present invention is not limited to this. For example, when an ignition device of a system different from the above-described laser ignition device 6 (such as an ignition plug or another laser ignition device) is provided, the operation of the laser ignition device 6 including the laser light generation unit 61 determined to be abnormal. May be stopped and switched to another ignition device. Thereby, a combustible air-fuel mixture can be reliably burned.

It is a figure which shows the structure of the engine of this embodiment, etc.

Explanation of symbols

1: cylinder block, 2: cylinder head, 3: intake valve, 4: exhaust valve, 5: fuel injection valve, 6: laser ignition device, 7: piston, 8: cylinder pressure detection sensor, 9: crank angle detection sensor, 10: Control device (ECU), 20: Combustion chamber, 61: Laser beam generator, 62: Half mirror, 63: Laser beam irradiator, 64: Laser beam detector, 65: Abnormality detector, 101: Laser beam output Control unit 102: Combustion analysis unit 103: Fuel injection valve / intake / exhaust valve control unit

Claims (7)

Ignition signal output control means for controlling the output of the ignition signal;
Laser light generating means for generating laser light based on the ignition signal;
Laser light irradiation means for irradiating the mixture in a combustion chamber of an internal combustion engine to activate the mixture;
Laser light detection means for detecting the laser light generated by the laser light generation means;
An abnormality detecting means for detecting an abnormality of the laser light generating means based on the detected laser light and the ignition signal;
A laser ignition device for an internal combustion engine. A half mirror disposed in a passage path of the laser light generated by the laser light generating means so as to be inclined with respect to a traveling direction of the laser light;
The laser beam irradiating unit irradiates the combustion chamber with either one of the laser beam transmitted through the half mirror and the reflected beam reflected from the half mirror,
2. The laser ignition device for an internal combustion engine according to claim 1, wherein the laser light detection means detects the other of the transmitted light and the reflected light.   3. The laser ignition device for an internal combustion engine according to claim 1, wherein the abnormality detection unit detects the abnormality by comparing the detected emission energy intensity of the laser light and the emission energy intensity of the ignition signal.   4. The laser ignition device for an internal combustion engine according to claim 1, wherein the abnormality detection unit detects the abnormality by comparing the detected light emission timing of the laser light and the light emission timing of the ignition signal. 5. An in-cylinder pressure detecting means for detecting an in-cylinder pressure in the combustion chamber of the internal combustion engine;
Combustion analysis means for performing combustion analysis based on the in-cylinder pressure;
With
The laser ignition device for an internal combustion engine according to any one of claims 1 to 4, wherein the abnormality detection unit detects the abnormality based on an analysis result by the combustion analysis unit and the ignition signal.   The laser ignition for an internal combustion engine according to any one of claims 1 to 5, further comprising an abnormality processing unit that limits at least one of a fuel injection amount and an intake air amount when the abnormality detection unit detects the abnormality. apparatus. An ignition device of a system different from the laser light generating means;
Ignition system switching means for igniting the air-fuel mixture by the ignition device when the abnormality detection means detects the abnormality;
A laser ignition device for an internal combustion engine according to any one of claims 1 to 6.

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