JP2006132493A - Laser igniting engine and method of operating the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser igniting engine capable of increasing ignitability by radiating a laser beam while shifting its radiating timings so that the laser beam can be radiated to a plurality of targets in a combustion chamber and operating an engine while supplementing a trouble even when a laser beam radiating facility fails. <P>SOLUTION: In this laser igniting engine, a laser beam from a laser beam oscillator is transmitted to a laser beam lead-in means installed in a cylinder head through optical fibers. A gas in the combustion chamber is ignited by plasma generated by radiating the laser beam to a target in the combustion chamber. The laser igniting engine comprises a laser beam branching device branching the laser beam from the laser generating device into multiple parts. The plurality of targets are installed and the plurality of laser beams branched by the laser beam branching device can be radiated to the targets. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is mainly applied to a premixed combustion laser ignition type engine such as a gas engine, and transmits a laser beam from a laser oscillation device to a laser beam condensing unit through an optical fiber, and from the laser beam condensing unit to a combustion chamber. The present invention relates to a laser ignition engine configured to ignite a gas in a combustion chamber by plasma generated by irradiation of a target, and an operation method thereof.

  In a premixed lean combustion gas engine, ignition is performed by igniting a rich mixture ratio gas in the auxiliary chamber by means of an ignition plug mounted in the auxiliary chamber, and the ignition flame is injected into the lean mixture in the main combustion chamber to cause main combustion. A pilot fuel is injected into the mixed gas in the auxiliary chamber by a spark plug ignition method or a pilot fuel injection valve mounted in the auxiliary chamber to ignite, and the ignition flame is injected into a lean mixture in the main combustion chamber. Instead of the pilot fuel injection ignition system that performs main combustion, a laser ignition system that generates plasma by irradiating laser light onto a target provided in a combustion chamber and ignites and burns gas in the combustion chamber is used. A technique for promoting ignition combustion and suppressing the amount of NOx generated has been proposed.

As a premixed lean combustion gas engine equipped with such a laser ignition system, techniques of Patent Document 1 (Japanese Patent Laid-Open No. 7-217521) and Patent Document 2 (Japanese Patent Laid-Open No. 9-42138) have been proposed.
In the technique of Patent Document 1, a plurality of wedge substrates are installed in the optical path of the laser beam, and each wedge substrate is rotated at a different rotational speed so that the laser beam is oscillated and irradiated in a wide range. It is composed.
Further, in the technique of Patent Document 2, a focus is provided so that laser light can always be irradiated onto the target by engine rotation in the optical path of the laser light between the laser oscillation device and one target provided on the piston surface. Equipped with a variable device.

JP-A-7-217521 Japanese Patent Laid-Open No. 9-42138

However, the prior art has the following problems to be solved.
That is, in the technique of Patent Document 1 (Japanese Patent Laid-Open No. 7-217521), a laser beam is passed while rotating the wedge substrate, and the laser beam is swayed to a target within a limited range of the upper surface of the piston in the combustion chamber. In the technique disclosed in Patent Document 2 (Japanese Patent Laid-Open No. 9-42138), the laser light is emitted by the engine rotation. However, it is possible to irradiate a plurality of targets in the combustion chamber with laser light, and to irradiate the laser light at different irradiation timings. There is no means to improve ignition performance.
In addition, in this conventional technique, when the laser beam irradiation equipment including the laser beam oscillation device breaks down, there is also a problem that the engine must be stopped because no supplement means is provided for the failure. Yes.

  In view of the problems of the prior art, the present invention is capable of irradiating a plurality of targets in a combustion chamber with laser light, and irradiating the laser light at different irradiation timings to improve ignition performance, and also laser light irradiation equipment An object of the present invention is to provide a laser ignition type engine that can operate the engine by compensating for the failure even when the engine fails.

The present invention achieves such an object, and transmits laser light from a laser oscillation device to a laser light introducing means mounted on a cylinder head through an optical fiber, and irradiates a target in a combustion chamber from the laser light introducing means. A laser ignition engine configured to ignite a gas in the combustion chamber by generated plasma, and includes a laser beam branching device for branching a laser beam from the laser oscillation device into a plurality, and a plurality of the targets are provided. Each target is irradiated with a plurality of laser beams branched by the laser beam branching device.
In such an invention, preferably, a laser beam cylinder distributing device that distributes the laser beam from the laser oscillation device to a plurality of cylinders is provided, and the laser beam branching device is provided in each cylinder. The laser beam distributed to the cylinder is branched by the laser beam branching device, and is irradiated to the targets provided in plural in each cylinder.

  According to this invention, the laser beam from the laser oscillation device is preferably distributed to each cylinder by the laser beam cylinder distributing device, and branched into a plurality of laser beams by the laser beam branching device provided for each cylinder and burned. Since irradiation is performed on a plurality of targets in the room, the irradiation of the laser beam to the targets arranged at a plurality of locations in the combustion chamber causes the combustion chamber gases to be ignited evenly, with the plurality of locations in the combustion chamber serving as ignition points for the combustion chamber gas. In addition, the occurrence of ignition failure can be avoided, and the ignition combustion time for the gas per target can be shortened, so that the ignition combustion performance is improved.

According to the present invention, in the laser ignition type engine, a plurality of laser oscillation devices are provided, and a laser beam cylinder distribution device that distributes laser light from each laser oscillation device to a plurality of cylinders corresponds to each laser oscillation device. The laser beam distributed from each of the plurality of laser beam cylinder distributing devices is introduced, and the plurality of laser beams are switched and applied to one target provided in the cylinder. A switching device is provided.
As an invention of a method for operating a laser ignition engine according to the invention, a plurality of laser beams from the plurality of laser oscillators are provided by a plurality of laser beam distribution means provided corresponding to each laser oscillator. Proposed is an operation method in which laser light is distributed to a plurality of cylinders for each laser light distributing means, and a plurality of laser lights from each of the plurality of laser light distributing means are switched and irradiated to one target provided in the cylinder.

  According to this invention, since a plurality of laser beam irradiation equipment including a laser beam cylinder distributing device and the like that provide a plurality of laser oscillation devices and distribute laser beams to a plurality of cylinders are provided, the laser beam oscillation device is included. When one of the laser beam irradiation facilities fails, the laser beam switching device can be switched to use the normal laser beam irradiation facility to operate the engine, and the laser beam irradiation facility has failed. In this case, the engine can be operated normally without stopping the engine, and the engine operability is improved.

In addition, the present invention is characterized in that a controller is provided for switching and irradiating laser light from one or a plurality of the laser oscillation devices to a target provided in the cylinder by shifting the irradiation timing.
As an invention of the method for operating the laser ignition engine according to the invention, the laser light from one or a plurality of the laser oscillation devices is switched and applied to the target provided in the cylinder at different irradiation timings. We propose a method for operating a laser ignition engine characterized by this.

  According to this invention, the first laser beam irradiation is performed by irradiating a single target installed in the combustion chamber or a plurality of targets arranged at a plurality of locations in the combustion chamber a plurality of times with different irradiation timings. Following the ignition and combustion of the combustion chamber gas by, the combustion chamber gas can be ignited and burned by the second and subsequent laser light irradiations, that is, a plurality of times of ignition and combustion can be performed. Combustion can be performed, fuel can be burned out, combustion performance and cycle efficiency can be improved, and NOx generation can be reduced.

According to the present invention, the laser beam from the laser oscillation device is split into a plurality of laser beams by the laser beam branching device and irradiated to a plurality of targets in the combustion chamber. Thus, the combustion chamber gas is evenly ignited, the occurrence of poor ignition is avoided, and the ignition combustion time for the gas per target can be shortened, so that the ignition combustion performance is improved.
Further, according to the present invention, when one of the laser beam irradiation facilities including the laser beam oscillation device fails, the engine is operated by switching the laser beam switching device to use the normal laser beam irradiation facility. Therefore, even when the laser beam irradiation facility fails, the engine can be operated normally without stopping, and the operability of the engine is improved.
Furthermore, according to the present invention, subsequent to the ignition combustion of the combustion chamber gas by the first laser beam irradiation, the ignition combustion of the combustion chamber gas by the second and subsequent laser beam irradiations can be performed a plurality of times. Thus, combustion in a so-called post-high combustion mode can be performed, fuel can be burned out well, combustion performance and cycle efficiency can be improved, and NOx generation can be reduced.

  Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this example are not intended to limit the scope of the present invention only to specific examples unless otherwise specified. Only.

FIG. 4 is a cross-sectional view around the combustion chamber of a single chamber laser ignition gas engine to which the present invention is applied.
In FIG. 4, 12 is a cylinder head of a gas engine (hereinafter referred to as engine), 10 is a piston, 11 is a cylinder liner, 13 is a combustion chamber defined by the cylinder head 12, piston 10 and cylinder liner 11, and 22 is a connectin. Grod, 23 is a crankshaft.
15 is an intake port, 14 is an intake valve for opening and closing the intake port 15, 17 is an exhaust port, and 16 is an exhaust valve for opening and closing the exhaust port 17.

1 is a laser oscillation device that oscillates a laser beam (laser pulse) 02, 2 is a laser control that controls a pulse interval of laser beam 02 oscillated from the laser oscillation device 1, laser beam energy (laser beam intensity), and the like. Device. Reference numeral 6 denotes a laser beam condensing lens installed in the cylinder head 12, and 9 denotes a support member that supports the condensing lens 6. Reference numeral 35 denotes a laser light introducing glass body that shields the condenser lens 6 side and the combustion chamber 13 side, and is made of transparent glass having heat resistance.
Reference numeral 50 denotes an optical fiber for transmitting the laser beam 02 from the laser oscillation device 1 to the condenser lens 6 side.

51 is a rotational speed detector for detecting the rotational speed of the engine, 52 is a load detector for detecting the load of the engine, 53 is a timing disk constituting a crank angle sensor, and a crank of the crankshaft 23 via the rotational shaft 23a. A corner is detected.
Reference numeral 3 denotes a controller that detects the detected value of the engine speed from the engine speed detector 51, detects the detected engine load value from the load detector 52, and detects the crank angle of the engine from the crank angle sensor (timing disk) 53. Each value is input, and based on the detected value of the engine speed or the detected value of the engine load, the pulse interval of the laser beam 02 corresponding to the engine speed or the engine load, the laser beam energy (the intensity of the laser beam) ) And the like, and the oscillation timing of the laser beam is calculated according to the firing order of each cylinder based on the detected crank angle value, and is input to the laser control device 2.

During operation of the laser ignition type gas engine having such a configuration, the detected value of the engine speed from the speed detector 51, the detected value of the engine load from the load detector 52, the crank from the crank angle sensor 53 The detected corner value is input to the controller 3.
The controller 3 controls the laser control device 2 to control the oscillation timing of the laser light 02 from the laser oscillation device 1 based on the detected value of the engine speed, the detected value of the engine load, and the detected value of the crank angle. Output a signal.
The laser control device 2 oscillates the laser beam 02 from the laser oscillation device 1 based on a control signal of the oscillation timing of the laser beam 02 input from the controller 3 to the laser control device 2. The laser beam 02 is transmitted through the optical fiber 50, enters the condensing lens 6 from the tip passing through the cylinder head 12, is condensed by the condensing lens 6, passes through the laser light introducing glass body 35, and is burned. The target 5 in the chamber 13 is irradiated. By irradiation with the laser beam 02, high temperature plasma is generated in the mixed gas in the combustion chamber 13, and the gas is ignited and burned.

The present invention relates to an improvement in a laser light transmission system in the laser ignition type gas engine as described above.
FIG. 1 is a block diagram of a laser light transmission system for a laser ignition engine according to a first embodiment of the present invention.
In FIG. 1, 1 is a laser oscillation device that oscillates laser light (laser pulse) 02, 2 is a pulse interval of laser light 02 oscillated from the laser oscillation device 1, laser light energy (laser light intensity), and the like. It is a laser control device to control. Reference numeral 50 denotes an optical fiber for transmitting the laser beam 02 from the laser oscillation device 1 as described later.
51 is a rotational speed detector that detects the rotational speed of the engine, 52 is a load detector that detects the load of the engine, 53 is a timing disk that constitutes a crank angle sensor, and is described above via the rotary shaft 23a (see FIG. 4). The crank angle of the crankshaft 23 is detected.

Reference numeral 3 denotes a controller that detects the detected value of the engine speed from the engine speed detector 51, detects the detected engine load value from the load detector 52, and detects the crank angle of the engine from the crank angle sensor (timing disk) 53. Each value is input, and based on the detected value of the engine speed or the detected value of the engine load, the pulse interval of the laser beam 02 corresponding to the engine speed or the engine load, the laser beam energy (the intensity of the laser beam) ) And the like, and the oscillation timing of the laser beam is calculated according to the firing order of each cylinder based on the detected crank angle value, and is input to the laser control device 2.
The laser light oscillation and control system described above is the same as the laser ignition type gas engine of FIG.

Reference numeral 7 denotes a laser beam cylinder distributing device that distributes the laser beam 02 from the laser oscillation device 1 to each cylinder. The laser beam 02 is split by a combination of a plurality of mirrors, a prism or the like to split the laser beam 02 into a plurality of beams. The light is split and distributed to each cylinder. That is, in the laser beam cylinder distributor 7, the laser beam 02 is received by the engine ignition order signal from the controller 3, distributed to each cylinder according to the ignition order, and the target distributor for each cylinder through the optical fiber 50. 4 is transmitted.
12 is a cylinder head, 10 is a piston, 11 is a cylinder liner, 13 is a combustion chamber defined by the cylinder head 12, piston 10 and cylinder liner 11, and the upper surface of the piston 10 faces the combustion chamber 13. A plurality of (two in this example) targets 5 are installed.

Reference numeral 4 denotes a target distributor (laser beam splitter) provided in each cylinder. The laser beam 02 distributed to each cylinder by the laser beam cylinder distributor 7 and transmitted through the optical fiber 50 is distributed to the number of targets 5. To do. In the target distributor 4, similarly to the laser light cylinder distributor 7, the laser light 02 is split into the same number as the number of the targets 5 by a combination of a plurality of mirrors, a prism, and the like.
Reference numeral 60 denotes a laser beam introducing device installed in the cylinder head 12. The condensing lens 6 is made of a condensing lens into which the laser beam 02 from the target distributor 4 is introduced through the optical fiber 50, and transparent glass having heat resistance. It is comprised by the laser beam introduction glass body 35 etc. which shield the side and combustion chamber 13 side.

In the first embodiment, in the controller 3, the laser light 02 from the laser oscillation device 1 is sent to the laser control device 2 based on the detected value of the engine speed, the detected value of the engine load, and the detected value of the crank angle. The control signal of the oscillation timing is output. In the laser control device 2, the laser light 02 is oscillated from the laser oscillation device 1 based on the control signal of the oscillation timing of the laser light 02 input from the controller 3 to the laser control device 2.
The laser beam 02 from the laser oscillation device 1 is incident on the laser beam cylinder distributor 7 through the optical fiber 50.

In the laser beam cylinder distribution device 7, the laser beam 02 is received in accordance with the ignition sequence signal of the engine from the controller 3, and is dispersed according to the ignition sequence and distributed to each cylinder. The data is transmitted to the distribution device 4.
In the target distributor 4, the laser light 02 distributed to each cylinder by the laser light cylinder distributor 7 and transmitted through the optical fiber 50 is distributed to the number of the targets 5.
The laser beam 02 distributed by the target distributor 4 is incident on the condenser lens 6 of each laser introducing device 60 provided corresponding to the target 5 through the optical fiber 50.
The laser beam 02 is collected by the condenser lens 6, passes through the laser beam introduction glass body 35, and is irradiated onto the target 5 in the combustion chamber 13. By irradiation with the laser beam 02, high temperature plasma is generated in the mixed gas in the combustion chamber 13, and the gas is ignited and burned.

According to the first embodiment, the laser beam 02 from the laser oscillation device 1 is distributed to each cylinder by the laser beam cylinder distributor 7, and the same number as the target 5 by the target distributor 4 provided for each cylinder. Since the laser beam is branched to irradiate a plurality of targets 5 in the combustion chamber 13, the irradiation of the laser beam 02 to the targets 5 arranged in a plurality of locations (two locations in this example) in the combustion chamber 13 A plurality of locations (two locations in this example) in the combustion chamber 13 serve as ignition points for the combustion chamber gas, and the combustion chamber gas is ignited evenly.
As a result, the occurrence of poor ignition can be avoided and the ignition / combustion time for the gas per target (5) can be shortened to improve the ignition / combustion performance.

FIG. 2 is a view corresponding to FIG. 1 showing a second embodiment of the present invention.
In the second embodiment, a plurality of laser oscillation devices 1a and 1b (two in this example) are provided, and a laser beam cylinder for distributing the laser beam 02 from each of the laser oscillation devices 1a and 1b to a plurality of cylinders. The same number of distributors 7a and 7b are provided corresponding to each of the laser oscillators 1a and 1b, and the plurality (two in this example) of laser beam cylinder distributors 7a and 7b to each of the distributors 7a and 7b are provided. The distributed laser beam 02 is transmitted to a laser beam switching device 160 provided for each cylinder.

In the laser beam switching device 160, the laser beam 02 that has passed through the optical fiber 50a from the laser beam irradiation equipment including the one side laser oscillation device 1a and the laser beam cylinder distribution device 7a, and the other side laser oscillation device 1b and the laser beam cylinder distribution. The laser beam 02 that has passed through the optical fiber 50b from the laser beam irradiation facility including the device 7b is switched as necessary to enter the condenser lens 6 of each laser introducing device 60.
Therefore, in the second embodiment, the laser beam switching device 160 can appropriately select a plurality of laser beams 02 and switch and irradiate one target 5 provided in the cylinder.

Therefore, according to the second embodiment, when the laser beam irradiation equipment including the laser oscillation device 1a on one side and the laser beam cylinder distributor 7a fails, for example, the laser beam switching device 1 is used.
60, the engine can be operated by switching to use a normal laser beam irradiation facility including, for example, the laser oscillation device 1b and the laser beam cylinder distributor 7b, and the engine can be operated even when the laser beam irradiation facility breaks down. It can operate normally without stopping.
Other configurations are the same as those of the first embodiment, and the same members are denoted by the same reference numerals.

  In the case of the second embodiment shown in FIG. 2, the third embodiment of the present invention oscillates laser beams 02 from a plurality of (two in this example) laser oscillators 1a and 1b. A plurality (two in this example) of laser beam cylinder distributors 7a and 7b provided corresponding to the devices 1a and 1b are distributed to a plurality of cylinders for each of the laser beam cylinder distributors 7a and 7b. The laser beam 02 from each of the plurality of laser beam cylinder distributors 7a and 7b is incident on the laser beam switching device 160 at different irradiation timings, and the laser beam switching device 160 transmits the laser oscillation device. 1a and the laser beam 02 that has passed through the laser beam cylinder distributor 7a, and the laser beam 02 that has passed through the laser oscillator 1b and the laser beam cylinder distributor 7b. By shifting the timing for irradiating the target 5.

Further, in the case of the first embodiment shown in FIG. 1, the laser beam 02 from the laser oscillation device 1 is distributed to a plurality of cylinders by the laser beam cylinder distributing device 7, and the laser beam of each cylinder is distributed by the controller 3. 02 is incident on the target distribution device 4 at different irradiation timings, and is irradiated from the target distribution device 4 to the two targets 5 in the combustion chamber 13.
Alternatively, it is possible to irradiate one target 5 without shifting the target distribution device 4 while shifting the irradiation timing.

According to the third embodiment, a single target 5 installed in the combustion chamber 13 or targets 5 arranged in a plurality of locations in the combustion chamber are irradiated with the laser beam 02 a plurality of times at different irradiation timings. Thus, subsequent to the ignition and combustion of the combustion chamber gas by the first laser beam irradiation, the combustion chamber gas can be ignited and burned by the second and subsequent laser beam irradiations, that is, a plurality of ignition combustions can be performed.
This makes it possible to perform combustion in a so-called post-high combustion mode as shown in FIG. 3B (FIG. 3A is a prior art), and fuel burnout is good. The combustion performance and cycle efficiency are improved, and the amount of NOx generated can be reduced.

  According to the present invention, it is possible to irradiate a plurality of targets in the combustion chamber with laser light and to irradiate the laser light with the irradiation timing shifted, so that the ignition performance can be improved and the laser light irradiation can be performed. It is possible to provide a laser ignition engine capable of operating the engine by complementing the failure even when the equipment breaks down.

1 is a configuration diagram of a laser light transmission system of a laser ignition engine according to a first embodiment of the present invention. FIG. 3 is a view corresponding to FIG. 1 showing a second embodiment of the present invention. In the cylinder pressure diagram in 3rd Example of this invention, (A) shows a prior art and (B) shows the case of this invention. It is sectional drawing of the surroundings of the combustion chamber of the single chamber type laser ignition type engine to which this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser oscillation apparatus 2 Laser control apparatus 02 Laser beam 3 Controller 4 Target distribution apparatus 5 Target 7, 7a, 7b Laser beam cylinder distribution apparatus 10 Piston 12 Cylinder head 13 Combustion chamber 14 Intake valve 16 Exhaust valve 50 Optical fiber 51 Rotation number detector 52 Load detector 53 Crank angle sensor 60 Laser beam introducing device 160 Laser beam switching device

Claims (6)

  Laser light from the laser oscillation device is transmitted to laser light introducing means mounted on the cylinder head through an optical fiber, and from the laser light introducing means to the gas in the combustion chamber by plasma generated by irradiating the target in the combustion chamber. The laser ignition type engine configured to ignite includes a laser beam branching device that branches the laser beam from the laser oscillation device into a plurality of branches, and a plurality of the targets are provided, and each target is branched by the laser beam branching device. A laser ignition type engine configured to be irradiated with each of a plurality of laser beams.   A laser beam cylinder distributing device for distributing the laser beam from the laser oscillation device to a plurality of cylinders and a laser beam branching device are provided in each cylinder, and the laser beam distributed to each cylinder by the laser beam cylinder distributing device is provided. 2. The laser ignition engine according to claim 1, wherein the laser light branching device is configured to irradiate a plurality of the targets provided in each cylinder by being branched by the laser beam branching device.   Laser light from the laser oscillation device is transmitted to laser light introducing means mounted on the cylinder head through an optical fiber, and from the laser light introducing means to the gas in the combustion chamber by plasma generated by irradiating the target in the combustion chamber. In a laser ignition type engine configured to ignite, a plurality of the laser oscillation devices are provided, and a laser beam cylinder distributor that distributes laser light from each laser oscillation device to a plurality of cylinders is provided in each laser oscillation device. The laser beams distributed by each of the plurality of laser beam distribution devices are introduced from the plurality of laser beam cylinder distribution devices, and the plurality of laser beams are switched and irradiated to one target provided in the cylinder. A laser ignition type engine comprising a laser beam switching device. 4. The controller according to claim 1, further comprising: a controller that switches and irradiates laser light from one or a plurality of the laser oscillation devices to a target provided in the cylinder at different irradiation timings. 5. The laser ignition type engine described in the section.   Laser light from the laser oscillation device is transmitted to the laser light introducing means mounted on the cylinder head through the optical fiber, and the gas in the combustion chamber is ignited by the plasma generated by irradiating the target in the combustion chamber from the laser light introducing means. In a method of operating a laser ignition engine configured to, a plurality of laser beams from the plurality of laser oscillators are provided by a plurality of laser beam distribution means provided corresponding to each laser oscillator. A laser ignition system characterized by distributing to a plurality of cylinders for each distribution means, and switching and irradiating a plurality of laser lights from each of the plurality of laser light distribution means to one target provided in the cylinder. How to run the engine.   Laser light from the laser oscillation device is transmitted to laser light introducing means mounted on the cylinder head through an optical fiber, and from the laser light introducing means to the gas in the combustion chamber by plasma generated by irradiating the target in the combustion chamber. In a method of operating a laser ignition engine configured to ignite, laser light from one or a plurality of the laser oscillation devices is switched and irradiated to a target provided in the cylinder at different irradiation timings. A method for operating a laser ignition engine characterized by the above.

Images