DE102006002694A1 - Laser apparatus and method and apparatus for igniting an air / fuel mixture in a combustion chamber of an internal combustion engine and internal combustion engine - Google Patents

Abstract

A laser device comprises a solid state actuator (52), a laser (40) and an elastically deformable lens (56). The lens (56) is arranged outside the laser (40), optically coupled to the laser (40) and mechanically coupled to the solid-state actuator (52) so that it can be elastically deformed by controlling the solid-state actuator (52).

Description

The The invention relates to a laser device comprising a laser and a solid body actuator includes. Furthermore, the invention relates to an internal combustion engine with a laser ignition device. Furthermore, the invention relates to a method and a device to ignite an air / fuel mixture in a combustion chamber of the internal combustion engine.

From the JP 100 94 886 A For example, a laser device is known which comprises an optical lens arranged in a cylindrical piezo element. An extension of the piezo element due to a corresponding input signal of the piezo element is transmitted to the circumference of the optical lens. As the piezo element expands, the optical lens, and thus a focus of the optical lens, is displaced along the optical axis of the optical lens. The optical lens is arranged coaxially with the piezoelectric element.

From the DE 20 2004 019 626 U1 is known an ignition system for an internal combustion engine. The ignition system includes at least one laser emitter capable of delivering a high energy beam of sufficient intensity for fuel-air mixture ignition and a light guide directing the laser beam to a combustion chamber of the engine. Furthermore, the ignition system comprises a combustion chamber light window which is attached to the combustion chamber, which is heat-resistant and is coupled to the light guide, and a laser control which controls the laser operation, the ignition pulses of the laser or a light switch, which can interrupt the light in the optical fiber or directly in front of the combustion chamber window, depending on phases of the internal combustion engine controls.

The The object of the invention is to provide a laser device the one very fast and precise Adjusting a laser beam of the laser device allows. In particular, it is an object of the invention to provide an internal combustion engine, a method and apparatus for igniting an air / fuel mixture to create in a combustion chamber of the internal combustion engine, the or that a very precise combustion allows.

The Task is solved through the independent ones Claims. Advantageous embodiments of the invention are characterized in the subclaims.

The Invention is characterized with respect a first aspect of the invention by a laser device. The laser device comprises a solid state actuator, a laser and an elastically deformable lens outside the laser. The elastic deformable lens is optically coupled to the laser. Further is the elastically deformable lens is coupled to the solid state actuator such that they are elastically deformable by driving the Festkörperaktuators is.

The Deforming the lens with the solid state actuator allows for very precise and very fast shifting of a focal point of the lens. This allows a laser beam of the laser very precise and very fast at different points to focus. this makes possible in particular when using the laser device for igniting a Air / fuel mixture in a combustion chamber of an internal combustion engine, while only one combustion process of the internal combustion engine Air / fuel mixture several times at different points in to ignite the combustion chamber. This can be very accurate Combustion of the air / fuel mixture and thus to a precise control contribute to the internal combustion engine.

Furthermore allows the elastic deformation of the lens with a relatively small Aktorstellweg of the solid state actuator an adjustment of the focal point in a relatively large spatial Range related to the Aktorstellweg.

In an advantageous embodiment of the first aspect of the invention is the elastically deformable lens in the axial direction with the solid body actuator coupled. The solid state actuator acts on the lens in the axial direction. This allows a Adjust and / or deform the lens so that the focal point the lens is displaced along an optical axis of the lens and / or that the optical axis is tilted with the focal point.

In a further advantageous embodiment of the first aspect of Invention is the elastically deformable lens in the radial direction with the solid state actuator coupled, in such a way that the solid-state actuator in the radial direction acts on the elastically deformable lens. This allows an adjustment and / or deforming the lens so that the focal point of the lens is along the optical axis of the lens is moved and / or that the optical axis is tilted with the focal point.

In a further advantageous embodiment of the first aspect of Invention is the laser over a Optical fiber coupled to the elastically deformable lens. This allows Arrange the laser arbitrarily spaced to the combustion chamber.

The invention is characterized in terms of a second aspect of the invention by an internal combustion engine. The internal combustion engine comprises at least one cylinder with a combustion chamber. Furthermore, the internal combustion engine comprises a laser ignition device and a laser beam for the laser ignition direction transparent window in the cylinder. The laser ignition device comprises a solid state actuator, a laser, and a lens outside the laser. The lens is optically coupled to the laser. Further, the lens is mechanically coupled to the solid state actuator such that by driving the solid state actuator, the laser beams are focused at different points in the combustion chamber. Through the window, the laser ignition device is optically coupled to the combustion chamber.

In an advantageous embodiment of the second aspect of the invention is the laser ignition device formed according to the laser device.

The Invention is characterized with respect of a third aspect of the invention by a method and a Device for igniting the air / fuel mixture in the combustion chamber of the internal combustion engine. To ignite the air / fuel mixture in the combustion chamber of the internal combustion engine a laser beam will become so within a combustion process different points in the combustion chamber focused that the air / fuel mixture is ignited in the combustion chamber at the different points.

In an advantageous embodiment of the third aspect of the invention is used to focus the laser beam at the different points shifted the focal point of the optical axis of the lens. This allows that Ignite air / fuel mixture at different points and wear like that to a very precise Combustion of the air / fuel mixture in the combustion chamber at. Especially at a shift operation of the internal combustion engine and / or others local fluctuations in the air / fuel ratio in the combustion chamber can Ignite of the air / fuel mixture at the different points in the combustion chamber to a very precise Contribute to combustion.

In a further advantageous embodiment of the third aspect of Invention will be the focal point of the lens along the optical axis postponed. This makes possible, the air / fuel mixture in the combustion chamber along the optical Ignite axis at different points.

In a further advantageous embodiment of the third aspect of the invention, the optical axis of the lens is adjusted. This allows the air / fuel mixture at any different points in the combustion chamber 9 to ignite.

In a further advantageous embodiment of the third aspect of Invention is to adjust the focus of the lens elastic deformed. In elastically deforming the lens, radii of the Lens changed. this leads to to move the focus. Even a slight change in one of the Both radii of the lens can shift the focal point in a relatively large one Effect area. Relatively large related in this context to Aktorstellweg.

advantageous Embodiments of the invention are explained in more detail below.

It demonstrate:

1 an internal combustion engine,

2 A first embodiment of an actuator device,

3 a section through the actuator device according to 2 .

4 the actuator device according to 2 with live solid state actuator,

5 a second embodiment of the actuator device,

6 a section through the second embodiment of the actuator device according to 5 .

7 the second embodiment of the actuator device with a solid state actuator under tension,

8th A third embodiment of the actuator device,

9 A fourth embodiment of the actuator device,

10 a section through the fourth embodiment of the actuator device according to 9 .

11 a program for igniting an air / fuel mixture in a combustion chamber of the internal combustion engine.

elements same construction or function are cross-figurative with the same Reference number marked.

An internal combustion engine ( 1 ) comprises an intake tract 1 , an engine block 2 , a cylinder head 3 and an exhaust tract 4 , The intake tract 1 preferably comprises a throttle valve 5 , a collector 6 and a suction tube 7 leading to a cylinder Z1 via an inlet channel into a combustion chamber 9 of the engine block 2 is guided. Furthermore, the intake tract 1 a pulse charging valve 16 include. The engine block 2 includes a crankshaft 8th , a connecting rod 10 and a piston 11 , The crankshaft 8th is over the connecting rod 10 with the piston 11 coupled to the cylinder Z1. The internal combustion engine preferably comprises, in addition to the cylinder Z1, further cylinders Z2, Z3, Z4. However, the internal combustion engine can also comprise any desired larger number of cylinders Z1 to Z4. The internal combustion engine is preferably arranged in a motor vehicle.

Preferred is in the cylinder head 3 an injection valve 18 arranged. Alternatively, the injection valve 18 also in the intake manifold 7 be arranged. In the exhaust tract 4 is preferably an exhaust gas catalyst 21 arranged, which is preferably designed as a three-way catalyst.

A control device 25 is provided, the sensors are assigned, which detect different measured variables and each determine the measured value of the measured variable. The control device 25 determined depending on at least one of the measured variables manipulated variables, which are then converted into one or more control signals for controlling the actuators by means of appropriate actuators.

The sensors are, for example, a pedal position transmitter 26 , the accelerator pedal position of an accelerator pedal 27 detected, an air mass sensor 28 , the air mass flow upstream of the throttle 5 detected, a first temperature sensor 32 sensing an intake air temperature, an intake manifold pressure sensor 34 that produces a manifold pressure in the collector 6 detected, a crankshaft angle sensor 36 which detects a crankshaft angle, which is then assigned a rotational speed N of the internal combustion engine.

ever according to embodiment The invention may be any subset of said sensors be present or it can also additional Sensors be present.

The actuators are, for example, the throttle 5 , the gas inlet and outlet valves 12 . 13 , the impulse charging valve 16 , the injection valve 18 and / or a laser ignition device, in particular a solid state actuator 52 the laser ignition device ( 2 )

The laser ignition device is a part of the internal combustion engine. The laser ignition device comprises an actuator device 44 , a laser 40 and preferably a light guide 42 , The actuator device 44 is optically over the light guide 42 with the laser 40 coupled. The power of the laser 40 is so high that by focusing a laser beam L of the laser 40 an air / fuel mixture in the combustion chamber 9 can be ignited. The actuator device 44 is over a window 46 in the cylinder Z1 to Z4 optically with the combustion chamber 9 coupled. The window 46 is designed so that it for the laser beams L from the laser 40 is transparent. The laser 40 is thus over the light guide 42 , the actuator device 44 and the window 46 with the combustion chamber 9 the engine optically coupled.

The actuator device 44 includes the solid state actuator 52 ( 2 ) and a lens 56 , Furthermore, the actuator device comprises 44 preferably a holder 54 for the lens 56 , an actuator housing 50 as well as a base plate 60 , The solid state actuator 52 is in the actuator housing 50 arranged. At an axial end of the solid state actuator 52 supports the solid state actuator 52 preferably on the base plate 60 and acts in the radial direction on the lens 56 one. The solid state actuator 52 can, for example, be tubular ( 3 ) be formed.

If a suitable voltage on the solid state actuator 52 is created, this expands. An extension X of the solid state actuator 52 is representative of an actuator travel of the solid state actuator 52 , A period of time that the solid state actuator 52 needed to expand, for example, can be in the range of a few microseconds. Furthermore, the extent X can be specified very precisely by the correspondingly precise predetermined voltage. The solid state actuator 52 is mechanical with the lens 56 coupled and thus allows a very fast and precise shifting of a focal point of the lens 56 , The following is the focal point of the lens 56 in the tension-free state of the solid-state actuator 52 is referred to as the output focal point F_0 and as the final focal point F_1 when the voltage across the solid state actuator 52 is created.

Moving the focus of the lens 56 allows the laser beam L of the laser 40 very fast and very precise to different points in the combustion chamber 9 to focus.

The very fast and very precise focusing of the laser beams L allows a multiple ignition of the same air / fuel mixture in a combustion process of the internal combustion engine at the different points in the combustion chamber 9 , In particular, in a stratified operation of the internal combustion engine, wherein the air / fuel ratio in the combustion chamber 9 subject to local variations, and / or systemic local variations in the air / fuel ratio in the combustion chamber 9 , For example, due to a non-uniform spray pattern of the injection valve 18 , so during a combustion process targeted at the different points in the combustion chamber 9 to be detonated. The different points are preferably in local areas of the combustion chamber 9 where, for example, a given air / fuel ratio is expected. A combustion process in this context refers to the burning of the air / fuel mixed in the combustion chamber 9 within a working cycle of the crankshaft 8th , in particular at the end of a compression stroke and at the beginning of a power stroke.

To shift the focus of the lens 56 to the different points in the combustion chamber 9 can the entire lens 56 be adjusted and / or the lens 56 be elastically deformed. If the lens 56 is elastically deformed, so includes the lens 56 preferably an elastically deformable material, for example silicone and / or a hydrogel.

The elastic deformation of the lens 56 ( 4 ) allows, at a relatively small extent X of the solid state actuator 52 the focal point of the lens 56 to move to a relatively large extent based on the extent X of the solid state actuator 52 , So that the lens 65 It can be deformed, it is from the holder 54 preferably kept stationary. The solid state actuator then moves relative to the lens 56 and the holder 54 , If the lens 56 deformed, so deformed by at least one of their radii. This causes the shifting of the output focal point F_0. The relationship between the size of the radii of the lens 56 and the position of the focal point can be determined for example by means of a lens equation used in optics. For example, the solid state actuator 52 in the axial direction on the lens 56 acting and can so at an inner radius of the Festkörperaktuators 52 of 1 mm, a lens diameter of 5 mm, a first radius of the lens 56 of 15 mm and a second radius of the lens 56 of 15 mm at an extension X of the solid state actuator 52 for example, 40 microns the focal point of the lens 56 along an optical axis O_A of the lens 56 move from a Ausgangsbrennpunkt F_0 to a final focal point F_1, which have a distance Y of about 1.1 mm to each other. This corresponds to an adjustment factor of approximately 30. That is, the focal point is about thirty times the extent X of the solid state actuator 52 is moved.

The solid state actuator 52 can also be in the radial direction on the lens 56 act ( 5 ) to the lens 56 to deform. Preferably, then several solid state actuators 52 provided and the lens 56 is made by the appropriately trained solid state actuators 52 held ( 6 ). Applying the voltage to the solid state actuator 52 then causes a compression of the lens 56 in the radial direction ( 7 ). This leads to a reduction in the radii of the lens 56 and thus to a shift of the output focal point F_0 towards the lens 56 to the final focal point F_1.

Adjusting the lens 56 includes a displacement, a twisting, a tilting and / or another mechanical movement, in which the lens 56 is displaced as a whole. If the lens 56 is adjusted, it is advantageous if the holder 54 the lens 56 with the solid state actuator 52 is coupled ( 8th ). The solid state actuator 52 , the Lens 56 and optionally the holder 54 are then moved uniformly to each other. Will now be the preferably tubular solid state actuator 52 driven, it has, for example, the extension X of 50 microns. The distance Y of the output focal point F_0 and the final focal point F_1 are then 50 micrometers.

Alternatively, it is also possible to use a plurality of axially acting solid-state actuators 52 for adjusting the lens 56 be used ( 9 . 10 ). The solid state actuators 52 For example, in the axial direction of the lens 56 and / or the holder 54 act. Furthermore, the solid state actuators 52 For example, evenly around the circumference of the lens 56 be arranged distributed. If any of the solid state actuators 52 the same voltage is applied, so the operation of the solid state actuators 52 a single tubular solid state actuator 52 , However, if different voltages to the individual solid state actuators 52 be applied, then the lens 56 tilted. This also makes the optical axis O_A of the lens 56 tilted and the focal point with the optical axis O_A moved. The laser beams L no longer incident parallel to the optical axis O_A are no longer focused on the final focal point F_1, but scatter around the final focal point F_1. The power of the laser 40 must be chosen in this case so high that still the ignition of the air / fuel mixture in the combustion chamber 9 is possible.

A program ( 11 ) for igniting the air / fuel mixture in the combustion chamber is preferably in the control device 25 stored. The control device 25 may in this context as a device for igniting the air / fuel mixture in the combustion chamber 9 be designated the internal combustion engine. The program is preferably timely before the ignition of the air / fuel mixture in the combustion chamber 9 started in a step S1, in which variables are initialized if necessary.

In In a step S2, the end focal point F_1 is determined, at which the Ignited air / fuel mixture shall be.

In a step S3, a control signal SG for the solid state actuator 25 determined to shift the focus of the lens 56 to the final focal point F_1.

In a step S4, the focal point along the optical axis O_A of the lens becomes 56 postponed. The optical axis O_A is not adjusted.

In a step S5, the optical axis O_A becomes the lens 56 adjusted and so the focus of the lens 56 postponed.

In step S4 and / or in step S5, the focal point of the lens 56 by adjusting and / or by deforming the lens 56 be moved.

In a step S6, the air / fuel mixture in the combustion chamber 9 ignited.

In a step S7, the program is ended. Preferably, however, during a combustion process, the steps S2 to S6 are processed several times and so the air / fuel mixture at the different points in the combustion chamber 9 ignited. Alternatively, several control signals SG for the solid state actuator 52 be determined and stored before the first ignition. The solid state actuator 52 is then controlled depending on the stored actuating signals SG.

The fast and precise focusing of the laser beam L can be used independently of the internal combustion engine in many different technical fields, for example in medical technology, electrical engineering and / or in manufacturing processes in general. The manufacturing processes may include, for example, welding, cutting and / or drilling with the laser beams L. The laser ignition device is then preferably referred to as a laser device. In the laser device, the focal point of the lens 56 preferably by the elastic deformation of the lens 56 postponed.

The invention is not limited to the specified embodiments. For example, the different embodiments can be combined. For example, the lens 56 through the solid state actuator 52 deformed and adjusted. Furthermore, the lens 56 be adjusted in the axial and in the radial direction. Furthermore, the lens 56 be deformed and adjusted in the radial and axial directions. The program for igniting the air / fuel mixture may comprise further or fewer steps S1 to S7, in which the focus is shifted accordingly.

Claims (12)

Laser device comprising - a solid state actuator ( 52 ), - a laser ( 40 ), - an elastically deformable lens ( 56 ) outside the laser ( 40 ), which optically with the laser ( 40 ) is mechanically coupled to the solid state actuator ( 52 ) is coupled by driving the solid state actuator ( 52 ) is elastically deformable. Laser device according to claim 1, in which the elastically deformable lens ( 54 ) in the axial direction with the solid state actuator ( 52 ) and in which the solid state actuator ( 52 ) in the axial direction on the lens ( 54 ) acts. Laser device according to one of the preceding claims, in which the elastically deformable lens ( 54 ) in the radial direction with the solid state actuator ( 52 ) is coupled in such a way that the solid state actuator ( 52 ) in the radial direction on the elastically deformable lens ( 54 ) acts. Laser device according to one of the preceding claims, in which the laser ( 40 ) via a light guide ( 58 ) with the elastically deformable lens ( 56 ) is optically coupled. Internal combustion engine comprising - at least one cylinder (Z1-Z4) with a combustion chamber ( 9 ), - a laser ignition device comprising a solid state actuator ( 52 ), a laser ( 40 ) and outside the laser ( 40 ) a lens ( 56 ), which optically with the laser ( 40 ) is mechanically coupled to the solid state actuator ( 52 ) is coupled, that by driving the solid state actuator ( 52 ) a laser beam (L) to different points (F_0, F_1) in the combustion chamber ( 9 ), - one for the laser ( 40 ) transparent window ( 46 ) in the cylinder (Z1-Z4) through which the laser ignition device optically with the combustion chamber ( 9 ) is coupled. Internal combustion engine according to claim 5, wherein the laser ignition device according to the laser device according to one of claims 1 to 4 is formed. Method for igniting an air / fuel mixture in a combustion chamber ( 9 ) of the internal combustion engine according to one of claims 5 or 6, wherein a laser beam (L) within a combustion process so on different points (F_0, F_1) in the combustion chamber ( 9 ) is focused that the air / fuel mixture in the combustion chamber ( 9 ) is ignited at the different points (F_0, F_1). Method according to Claim 7, in which, for focusing the laser beam (L) at the different points (F_0, F_1), a focal point of an optical axis (O_A) of the lens (O_A) 56 ) is moved. The method of claim 8, wherein the focal point (F_0) along the optical axis (O_A) is shifted. Method according to one of Claims 8 or 9, in which the optical axis (O_A) of the lens (O_A) 56 ) is adjusted. Method according to one of Claims 8 to 10, in which, for displacing the focal point, the lens ( 56 ) is elastically deformed. Device for igniting an air / fuel mixture in a combustion chamber ( 9 ) of the internal combustion engine according to one of claims 6 or 7, which is designed to focus a laser beam (L) on different points (F_0, F_1) in the combustion chamber ( 9 ) within a combustion process of the internal combustion engine, so that the air / fuel mixture in the combustion chamber ( 9 ) is ignited at the different points (F_0, F_1).