JP2006250090A - Laser ignitor provided with warm-up device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide technology for shortening warm-up time in a case where a laser oscillator is used for a laser ignitor. <P>SOLUTION: This laser ignitor provided with a warm-up device is provided with the laser ignitor 35 including the laser oscillator 36 to radiate laser beam to mixture in a combustor on chamber 16 of an internal combustion engine for ignition, and an electric warm-up device 40 to heat the laser oscillator when actuation of the laser oscillator is started. Warm-up time for heating the laser oscillator by the warm-up device to make it ready for oscillation is shortened. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a laser ignition device with a warming device provided with a warming device for heating a laser oscillator.

  As an ignition device for igniting (igniting) an air-fuel mixture in a combustion chamber in an internal combustion engine, an ignition device including an ignition coil and an ignition plug is generally used. The power supply voltage is boosted to a high voltage by an ignition coil, a spark is generated by an ignition plug, and an air-fuel mixture is ignited (spark ignition). However, spark ignition may not be appropriate depending on the characteristics of the fuel (for example, flame-retardant fuel). The spark plug is fixed at a predetermined position on the cylinder head in a predetermined direction. For efficient ignition, the position of the ignition part is changed according to the direction and concentration of the spray injected from the fuel injection valve. It is desirable to be able to do it.

In consideration of such circumstances, in recent years, a laser ignition device that ignites an air-fuel mixture with laser light emitted from a laser oscillator has been developed (see Patent Document 1). According to the laser ignition device, even a flame-retardant fuel can be ignited by a laser beam having a high energy density, and the ignition position can be easily changed by adjusting a lens.
JP-A-9-303244

  In general, a laser oscillator requires a predetermined warm-up time until the laser beam is oscillated after starting (starting), and it is desirable that the warm-up time be as short as possible regardless of the use of the laser oscillator (for ignition or other purposes). . This requirement is particularly severe when used in a vehicle ignition device, otherwise the engine start is delayed.

  A technique for shortening the warm-up time of a laser oscillator used other than the ignition device has been developed. For example, a technique disclosed in Japanese Patent Application Laid-Open No. 2002-319723 relates to a gas laser used in a laser processing machine, and measures a pause time of a laser oscillator by a measuring unit in order to automate a warm-up time. However, the control based on the measurement result of the measuring means is complicated. The technique disclosed in Japanese Patent Laid-Open No. 9-216077 relates to a gas laser used for laser processing and adds an idling pulse generating circuit to promote the rise of the laser. However, the control of the idling pulse generation circuit is complicated.

  As can be seen, the technology relating to the shortening of the warm-up time of the laser oscillator is only used in fields other than the ignition device, and the technology for shortening the warm-up time of the laser oscillator used in the ignition device is not known. Further, the technology for shortening the warm-up time used in fields such as laser processing is complicated to control.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a laser ignition device with a warming device that has a simple configuration and that can effectively shorten the warming time of a laser oscillator.

  (B) The inventor of the present invention has conceived that the laser oscillator is directly heated by an electric heater or a heating medium, and has completed the present invention. According to a first aspect of the present invention, a laser ignition device with a warming device includes a laser ignition device including a laser oscillator that irradiates a mixture in a combustion chamber of an internal combustion engine and ignites the mixture. And an electric warming device that heats the laser oscillator at the start of operation. The biggest feature is that the laser oscillator that ignites the combustible mixture is heated by an electric warming device.

  According to a second aspect of the present invention, a laser ignition device with a warming device includes a spark ignition device for igniting an air-fuel mixture in a combustion chamber of an internal combustion engine with sparks, and a laser oscillator. A laser ignition device that ignites an air-fuel mixture in a combustion chamber with a laser beam, a control device that operates a spark ignition device or a laser ignition device according to the operating state of the internal combustion engine, and a laser oscillator that heats the laser oscillator at the start of operation And a warming device. The greatest feature is that a spark ignition device and a laser ignition device are provided, and either one is selected and used according to the operating state of the internal combustion engine.

  (B) Various aspects of the components of the present invention will be described below.

a. Internal combustion engine The internal combustion engine of the first and second inventions is typically a vehicle engine, but is not necessarily limited to a vehicle. The internal combustion engine includes a cylinder, a piston, a fuel injection valve that injects fuel into the combustion chamber, and an ignition device that ignites a combustible mixture. The fuel injection valve may be a type that injects fuel into the intake holes (manifold type) or a type that injects fuel into the combustion chamber (direct injection type).

b. Ignition device There are two types of ignition devices of the present invention. The ignition device of the first invention (first type) consists only of a laser ignition device, and the ignition device of the second invention (second type) consists of a spark ignition device and a laser ignition device, and either one is selected. The laser ignition devices of the first invention and the second invention may be composed of any of a solid-state laser, a semiconductor laser, and a combination of both. The laser oscillator is preferably attached to the top of the cylinder head, but it may be attached elsewhere, and the laser beam may be guided to the combustion chamber by an optical fiber. As the spark ignition device of the second invention, a general-purpose device that includes an ignition coil and a spark plug and is attached to a cylinder cover can be used.

c. Warm-up device, heating medium When the internal combustion engine is a vehicle engine, the warm-up device consists of an electric heater (heater coil) that is operated by an on-vehicle power source (type a), and the heater coil can be spirally wound around a laser oscillator it can. The warming device can also use a relatively high-temperature heating medium circulating in the vehicle (b type), and the heating medium is exhaust gas flowing through the exhaust pipe or conditioned air generated by the air conditioner (particularly warm air) It is. The warming device contains a laser oscillator and is constituted by a tube member through which a warming refrigerant flows. For example, it may be an exhaust gas distribution pipe that branches from an exhaust pipe and in which high-temperature exhaust gas flows, or an air-conditioning air distribution pipe that extends from an air conditioner and in which high-temperature conditioned air flows.

d. Control device, temperature detection means The heater coil of the first invention can generate heat in conjunction with the opening of a vehicle door, for example, before the engine is started by the control device. In the second invention including two ignition devices, one of the ignition devices is selectively operated by the control device in accordance with the operating state of the internal combustion engine. Specifically, the spark ignition device is operated when the internal combustion engine is started, and the laser ignition device is operated after the start. The spark ignition device starts its operation when the ignition key is turned on, and the switching timing from the spark ignition device to the laser ignition device is, for example, when the temperature of the laser oscillator detected by the temperature detecting means reaches a predetermined value. Further, a flow rate adjusting means is provided in the middle of the exhaust gas circulation pipe and the conditioned air circulation pipe, and the opening degree can be adjusted based on the detection result by the temperature detection means.

  According to the laser ignition device with a warming device according to the first invention, the laser oscillator is directly heated (warmed up) by the electric warming device at the time of starting, so that the laser oscillator can be oscillated in a short time and combustible mixing in the combustion chamber is achieved. I can ignite immediately. Since the laser oscillator is directly heated, the effect of warming is great and complicated control is unnecessary.

  According to the laser ignition device with a warming device according to the second aspect, the warming device can use an in-vehicle power source, and the heater coil is wound around the laser oscillator, so that the heating efficiency is good. According to the laser ignition device with a warming device according to the third aspect, since the heater coil heats the laser oscillator from when the door is opened, it can oscillate immediately when the ignition key is turned on.

  According to the laser ignition device with a warming device according to the second aspect of the invention, the spark ignition device or the laser ignition device can be properly used according to the operating state of the internal combustion engine, and the ignition of the combustible mixture is ensured. According to the laser ignition device with a warming device of claims 5 and 6, since the spark ignition device is used when starting the internal combustion engine, warming is unnecessary and ignition can be performed immediately. Since the laser igniter which has been warmed up is used after starting, it can ignite immediately after switching.

  According to the laser ignition device with a warming device of claim 7, since the warming device uses the heat of exhaust gas, the warming is reliable and the energy is effectively used. According to the laser igniter with the warming device of the eighth aspect, since the air conditioner installed in the vehicle is used, it is not necessary to add special equipment or devices. According to the laser ignition device with a warming device of the ninth aspect, it is possible to select the optimum degree of heating by adjusting the supply amount of exhaust gas or conditioned air according to the detected temperature.

  Hereinafter, an embodiment (laser ignition device with a warming device) according to the best mode will be described with reference to the accompanying drawings.

<First Embodiment>
(Constitution)
FIG. 1 shows a first embodiment in which the internal combustion engine is a vehicle engine and the warming device is a heater coil. The engine includes a cylinder head 10, a piston 13, a cylinder cover 15, a fuel injection valve 26, a laser ignition device 35, a warming device 40, and the like. Among these, a water jacket 11 through which cooling water circulates is formed in the cylinder head 10, and a piston 13 is slidably fitted in the cylinder bore 12. An upper end opening of the cylinder head 10 is covered with a cylinder cover 15, thereby defining a combustion chamber 16.

  An intake pipe 21 is disposed on one side of the cylinder head 10 and an exhaust pipe 55 is disposed on the other side. The intake pipe 21 supplies intake air (outside air) to the combustion chamber 16, has an air cleaner (not shown) at its inlet, and has an outlet connected to the intake hole 17. An intake valve 23 is disposed in the vicinity of the intake hole 17 and is opened and closed by an opening / closing mechanism 24 at a predetermined time. A fuel injection valve 26 is disposed in the vicinity of the intake valve 23 and is connected to a fuel tank 29 via a fuel pipe 27. The fuel in the fuel tank 28 is pumped to the fuel injection valve 26 through the fuel pipe 27 by the fuel pump 29.

  A laser ignition device 35 is disposed at the top of the cylinder cover 15, and a warming device 40 is disposed around the laser ignition device 35. These details are described below. The exhaust pipe 55 discharges combustion gas, and its inlet is connected to the exhaust hole 18 of the combustion chamber 16. The exhaust valve 57 disposed in the vicinity of the exhaust hole 18 is opened and closed by an opening / closing mechanism 58 at a predetermined time.

  Next, the details of the laser ignition device 35 and the warming-up device 40 will be described with reference to FIGS. As can be seen from FIG. 2, the heater coil 41 of the warming device 40 is spirally wound around the outer peripheral surface of the laser oscillator 36 of the laser ignition device 35, and both ends thereof are connected to the in-vehicle battery 43, and the switch 44 is disposed in the middle. ing. A temperature sensor 38 is disposed near the laser oscillator 36 to detect the temperature of the laser oscillator 36.

  As can be seen from FIG. 3, the signal of the opening / closing switch 48 of the door (not shown) and the detection result of the temperature sensor 38 are input to the ECU 46. The ECU 46 turns on the switch 44 in conjunction with the opening of the door. Further, the laser oscillator 36 is operated in conjunction with turning on an ignition key (not shown).

(Function)
Next, the operation of the first embodiment will be described, but the description of the operation not directly related to the present invention will be omitted. When the occupant opens the door to get into the vehicle, the switch 48 in FIG. 3 detects that the switch 44 is turned on by a command from the ECU 46, and current flows from the in-vehicle battery 43 to the heater coil 41. Then, the heater coil 41 generates heat and heats the laser oscillator 36. The temperature of the laser oscillator 36 is detected by the temperature sensor 38, and the current value is controlled so as to reach a predetermined temperature (for example, 18 to 28 ° C.) within a predetermined time.

  When the ignition key is turned on, the piston 13 descends in the intake process, the outside air is sucked into the combustion chamber 16 from the intake pipe 21, and fuel is injected from the fuel injection valve 26 to generate a combustible mixture in the combustion chamber 16. In the compression process, the piston 13 rises to compress the combustible mixture, and the combustible mixture is ignited by the laser oscillator 36 immediately before reaching the top dead center.

(effect)
According to the first embodiment, the following effects can be obtained. First, since the laser oscillation part 36 is directly warmed by the heater coil 41 wound around its outer peripheral surface, the heating efficiency is good, and complicated control of the heat generation timing and time is unnecessary. Since the current flows through the heater coil 41 when the door is opened, the laser oscillator 36 is ready to oscillate when the ignition key is on, and can immediately ignite the combustible mixture. Furthermore, the current value of the heater coil 41 can be selected as an optimum value according to the detection result of the temperature sensor 38.

Second Embodiment
(Constitution)
Next, a second embodiment of the present invention will be described. In the second embodiment, a spark ignition device 60 and a laser ignition device 65 are provided in parallel, and the laser ignition device 65 includes a laser oscillator 66 that uses exhaust gas as a heating medium. Other configurations are basically the same as those of the first embodiment. In the following, different configurations will be mainly described. A spark plug 61 of a spark ignition device 60 is attached to the top of the cylinder cover 15 in the vertical direction, and the ignition portion faces the combustion chamber 15.

  The spark plug 61 is connected to an ignition coil (not shown) and ignites by a high voltage generated by the ignition coil. In addition, a laser oscillator 66 is attached in the oblique direction in the vicinity of the spark plug 61. A temperature sensor 68 is disposed near the laser oscillator 66, and the detection result is output to the ECU 70. The laser oscillator 66 and the like are accommodated in a branch pipe 72 described below. A branch pipe 72 branches off from the middle of the exhaust pipe 55 immediately downstream of the exhaust hole 18 and extends toward the top of the cylinder cover 15. The branch pipe 72 includes a branched first portion 73, a third portion 74 connected to the cylinder cover 15, and a second portion 72 connecting the both. An opening / closing valve 79 is disposed at the branch point of the first portion 73 and the opening thereof is opened. The degree is controlled by the ECU 70 (control device).

  The enlarged portion 75 of the third portion 74 defines a vertical chamber 76, and the laser oscillator 66 and the temperature sensor 68 are accommodated in the chamber 76. The ECU 70 selects and operates the spark ignition device 60 or the laser ignition device 65 based on the signal from the temperature sensor 68. The temperature information from the temperature sensor 68 is also used to adjust the opening degree of the on-off valve 79.

(Function and effect)
In the second embodiment, when the engine is started, the ECU 70 selects the spark ignition device 60 based on the ignition key 82 being turned on. Then, the electric power of the in-vehicle battery (not shown, see 43 in FIG. 2) is boosted by the ignition coil, the ignition plug 61 is ignited, and the combustible mixture in the combustion chamber 16 is ignited. At this time, the on-off valve 79 is closed.

  After starting the engine, the laser ignition device 65 is selected. The switching timing from the spark ignition device 60 to the laser ignition device 65 is determined by the temperature detected by the temperature sensor 68, and is switched by a command from the ECU 70 when the temperature reaches a predetermined temperature. Here, prior to this switching, the on-off valve 79 is opened by a command from the ECU 70. Then, a part of the exhaust gas flowing through the exhaust pipe 55 flows into the branch pipe 72, and the laser oscillator 66 is heated when it flows through the chamber 76. Thus, the laser oscillator 66 preheated with the exhaust gas can oscillate the laser beam immediately from the switching time.

  The effects of the second embodiment are as follows. The spark ignition device 60 is used when starting the engine, and the laser ignition device 65 is used after starting, that is, the ignition device is properly used according to the operating state of the engine. No warm air is required for the spark plug 61 that ignites the combustible air-fuel mixture when the engine is started. Since the laser oscillator 66 used after the engine is started is heated by the temperature of the exhaust gas, the warm-up time can be shortened and can be oscillated immediately after switching. Moreover, since the switching time is determined based on the temperature information from the temperature sensor 68, the control is easy and accurate. Moreover, if it is not according to this invention, the heat of waste gas discharged | emitted wastefully can be utilized effectively, and it leads to energy saving.

<Modification>
The modification shown in FIG. 5 differs from the second embodiment in that conditioned air is used as a heating medium. That is, a pipe 87 extending from the air conditioner (air conditioner) 85 to the top of the cylinder cover 15 includes a first portion 88 extending from the air conditioner 85 and a second portion 90 attached to the top of the cylinder cover 15. A laser oscillator 95 is disposed in a longitudinal chamber 92 defined by the enlarged portion 91 of the second portion 90, and a temperature sensor 97 is disposed in the vicinity thereof. The detection result of the temperature sensor 97 is output to the ECU (control device) 100, and the ECU 100 controls the operation of the air conditioner 85. In addition, the structure and arrangement | positioning location of the spark ignition device 60 are the same as 2nd Embodiment.

  In this modification, the ECU 100 selects the spark plug 61 when starting the engine and selects the laser oscillator 95 after starting, as in the second embodiment. Prior to switching from the spark plug 61 to the laser oscillator 95, conditioned air (particularly warm air) is supplied from the air conditioner 85 to the chamber 92 through the pipe 87 in accordance with a command from the ECU 100. Then, the warm air flowing in the chamber 92 heats the laser oscillator 95. In this way, the laser oscillator 95 that has been heated in advance can oscillate the laser beam immediately after switching.

  According to this modification, the laser oscillator 95 is heated by the temperature of the conditioned air generated by the air conditioner 85, so that it can oscillate immediately after switching and the warm-up time can be shortened. Since the conditioned air uses the conditioned air generated by the air conditioner 85 originally installed in the vehicle, it is not necessary to add a special device or device, and an increase in cost can be suppressed.

1 is an overall explanatory diagram of a laser ignition device with a warming device according to a first embodiment of the present invention. It is principal part explanatory drawing of FIG. It is operation | movement explanatory drawing of 1st Embodiment. It is a whole explanatory drawing of the laser ignition device with a warming device by a 2nd embodiment. It is whole explanatory drawing of the laser ignition device with a warming device by 3rd Embodiment.

Explanation of symbols

13: Piston 15: Cylinder head 16: Combustion chamber 23: Intake valve 26: Combustion injection valve 35: Laser ignition device 36: Laser oscillator 38: Temperature sensor 40: Warm-up device 41: Heater coil 43: In-vehicle power supply 46: ECU
48: Door switch

Claims (9)

A laser ignition device (35) including a laser oscillator (36) for irradiating a gas mixture in a combustion chamber (16) of an internal combustion engine with laser light for ignition;
An electric warming device (40) for heating the laser oscillator at the start of operation of the laser oscillator;
A laser ignition device with a warming device, comprising:   2. The laser ignition device with a warming device according to claim 1, wherein the internal combustion engine is a vehicle engine, and the warming device includes a heater coil wound around the laser oscillator and driven by a vehicle-mounted power source.   The laser ignition device with a warming device according to claim 2, wherein the control device (46) commands the start of heating of the heater coil based on detection of a detection means (48) for detecting opening of a vehicle door. A spark ignition device (60), including an ignition coil and a spark plug (61), for igniting the air-fuel mixture in the combustion chamber (16) of the internal combustion engine with a spark;
A laser ignition device (65) including a laser oscillator (66) and igniting an air-fuel mixture in the combustion chamber with a laser beam;
A control device (70) for operating the spark ignition device or the laser ignition device according to the operating state of the internal combustion engine;
A warming device (75; 91) for heating the laser oscillator at the start of operation of the laser oscillator;
A laser ignition device with a warming device, comprising:   The laser ignition device with a warming device according to claim 4, wherein the control device selects the spark ignition device when starting the internal combustion engine, and selects the laser ignition device after starting the internal combustion engine.   6. The pre-air control device according to claim 5, wherein the pre-air control device commands switching from the spark ignition device to the laser ignition device based on a detection result of a temperature detection means (68; 97) for detecting the temperature of the laser oscillator. Laser ignition device with warm-up device.   The laser ignition device with a warming device according to claim 6, wherein the internal combustion engine is an engine of a vehicle, and the warming device includes a tube member (75) that houses the laser oscillator and through which exhaust gas flows. .   7. The laser ignition with a warming device according to claim 6, wherein the internal combustion engine is an engine of a vehicle, and the warming device contains the laser oscillator, and comprises a pipe member (91) through which conditioned air flows. apparatus.   The laser igniter with a warming device according to claim 8, wherein the control device issues a command for adjusting an opening degree of a flow rate adjusting means (79) for adjusting a flow rate of exhaust gas or conditioned air in the pipe member.

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