Surface

Technical Field

The present invention relates in a first as pect to a method for cleaning a surface, in particular a vehicle surface, with an apparatus comprising a nozzle.

In a second aspect, the invention refers to the apparatus for cleaning a vehicle and in a third aspect to the noz zle.

Background Art

Cleaning of surfaces that are sensitive to scratches is very challenging. The challenge is to find a way to clean the surface without damaging it at the same time. Common methods like scrubbing or wiping of a surface might result in scratches on the surface, generated by means of small particles that are trapped e.g. between a scrubber and the surface or between a wiper and the surface and moved back and forth over the respective surface during the cleaning step. On the other hand, if a method for cleaning a surface is too gentle, residues remain on the surface and are not properly removed by the respective cleaning method.

In particular, cleaning of a surface of a ve hicle is very challenging. A vehicle can get very dirty during its use but at the same time, the car lacquering is very sensitive to scratches.

State of the art cleaning methods often cannot fulfil the requirements of cleaning a surface reliably and at the same time preventing the surface from damages.

In addition, if the state-of-the-art cleaning methods might fulfil such requirements, as the steamer cleaning method, the method is very energy consuming. Disclosure of the Invention

The problem to be solved by the present inven tion is therefore to provide a method and an apparatus for cleaning a vehicle surface that is gentle to a sensitive surface during the cleaning process and does not generate scratches on the surface.

This problem is solved by the subjects of the independent claims.

Accordingly, a first aspect of the invention refers to a method for cleaning a vehicle surface compris ing an apparatus. The apparatus comprises a holder that is adapted to hold a vehicle comprising the surface that is supposed to be cleaned.

Advantageously, the holder is adapted to allow a vehicles entering the holder and leaving the holder.

In addition, the apparatus comprises a nozzle assembly. The nozzle assembly comprises a robot arm, a nozzle and a controller module.

The robot arm is adapted to move at least one nozzle according to a cleaning path. In a further advanta geous embodiment of the invention, the robot arm might comprise at least two or three, four or five nozzles. In particular, the more than one nozzles might be adapted for different functionalities. In particular, one nozzle might provide steam whereas one nozzle serves as blow dryer, for blow drying the surface.

Advantageously, each nozzle, if there are more than one nozzle, can be controlled individually.

Advantageously, if there is more than one noz zle, the multiple nozzles are coordinated with each other for cleaning or blow drying the surface or multiple sur faces respectively.

Further advantageously, the multiple nozzles are individually cleaning or blow drying the surface or multiple surfaces respectively, independently from each other.

The at least one nozzle of the nozzle assembly is adapted for discharging steam and/or atomized liquid towards a vehicle surface and/or for blow drying.

Advantageously, the discharged steam or atom ized liquid corresponds to discharged water steam and dis charged atomized water.

To provide all the functionalities, the nozzle might comprise a steam, a water, and/or an air inlet, and a steam, a water, and/or an air outlet. Embodiments of such a nozzle are shown in the experimental section.

In an advantageous embodiment of the invention, the nozzle is a steam nozzle.

In a further advantageous embodiment of the invention, the nozzle is an atomizing nozzle. Atomizing nozzles are well known from prior art. An atomizing nozzle is ideal for producing extremely fine droplets of a liquid that is discharged from the nozzle. Generally speaking, atomizing nozzles work on the principle that a pressurized gas is used to impact upon a fluid being sprayed. The impact of the gas atomizes the fluid, meaning that it breaks the fluid flow into individual droplets.

Steam nozzle are well known from prior art. They are ideal for producing steam that are discharged from the steam nozzle. Steam in particular, refers to a hot water vapour or saturated water vapour.

In an advantageous embodiment, the nozzle as sembly comprises more than one nozzle, wherein a first nozzle is adapted to discharge steam or atomized liquid towards a spot on the surface, and a second nozzle is adapted to blow dry the surface on the spot where the first nozzle has discharged the steam or atomized liquid.

The controller module is adapted for control ling the movements of the robot arm according to the clean ing path and for controlling the discharging of the nozzle or if there are more than one nozzle, of the multiple nozzles.

The method comprises the steps of

- scanning the vehicle surface in the holder by means of the vision module to gain surface data,

- calculating the cleaning path from the surface data provided by the vision module by means of the calcu lation module, forwarding the cleaning path to the controller mod ule of the nozzle assembly,

- controlling the at least one nozzle to follow the cleaning path and discharging steam and/or the atom ized liquid and/or blow dry, for cleaning and/or drying the vehicle surface.

The method further comprises the step of di recting the steam or atomized liquid to the vehicle sur face, wherein the shortest distance d between the surface and a first end of the nozzle that discharges the steam or atomized liquid in downstream direction is 1cm < d £ 20cm, advantageously 1cm < d £ 7cm, very advantageously 4cm < d < 7cm.

In a further advantageous embodiment, the dis tance d is 3cm < d £ 20cm, in particular 3cm < d £ 7cm, meaning in particular that the inventive method works also very well from a certain distance, which allows to clean a greater area in once.

Advantageously the distance d is 1cm < d £ 7cm, in particular 3cm < d £ 7cm, in particular 4cm < d £ 7cm for atomized liquid and/or 1cm < d £ 5cm, in particular lcm < d £ 5cm, for steam.

In particular, if not mentioned otherwise, the given values in this specification work for a nozzle dis charging steam and for a nozzle discharging atomised liq uid.

In an advantageous embodiment of the invention using an atomised liquid, in particular atomized water, an impact temperature Ti of atomized liquid is 80°C > Ti > 40°C, in particular 65°C > Ti > 40°C, on impact on the surface.

In particular, the impact temperature Ti refers to the temperature of the atomised liquid that is measured if it hits the surface. In particular, the impact temper ature might be measured by a attaching a temperature sensor to the surface on the spot where the atomized liquid hits the surface.

In particular, the nozzle is adapted to dis charge the liquid in a way that the impact temperature Ti of the atomized liquid and/or the steam if it hits the surface is in the range of 80°C > Ti > 40°C, in particular 65°C > Ti > 40°C.

In an advantageous embodiment of the invention, a first end of the nozzle is arranged at the end of the longitudinal axis of the nozzle in downstream direction.

In an advantageous embodiment of the invention, the first end of the nozzle corresponds to a liquid/gas discharge orifice where the steam/atomized liquid/air is discharged .

In a further advantageous embodiment of the invention, the first end of the nozzle extends beyond the discharge orifice of the nozzle in a downstream direction of the longitudinal axis, and forms a first end discharge orifice to discharge the steam/atomized liquid/air.

In a further advantageous embodiment of the invention, the nozzle comprises the steps of discharging the steam/and or atomized liquid with a pressure of pi of lObar > pi > O.lbar.

In a further advantageous embodiment of the invention, an angle b between the longitudinal axis of the nozzle and the surface plane is 90° > b > 30°, in particular 90° > b > 45°, very particular 80° > b > 70°, very partic ular essentially 75°.

In a further advantageous embodiment, the method comprises the steps of moving the first end of the nozzle with a velocity v _n of 1.00 m/s ³ v _n ³ 0.01 m/s, in particular 1.00 m/s ³ v _n ³ 0.01 m/s, very particular 0.6 m/s ³ v _n > 0.01 m/s, in a lateral direction relatively to the surface of the vehicle.

In particular, the end of the nozzle keeps the distance d when it is moved over the surface.

In a further advantageous embodiment of the invention, the method comprises the step of blow drying, respectively blow cleaning, the surface before the steam/atomized liquid is directed towards the surface, or synchronous with directing the atomized liquid to the sur face.

The blow drying, respectively the blow clean ing, of the surface before discharging the steam or atom ized liquid to the surface increases the cleaning effect of the method.

Advantageously, a second nozzle of the nozzle assembly is adapted to blow air to the surface before and after the discharge of the steam or atomized liquid.

Advantageously, the blow drying of the surface is achieved by means of an assembly of the nozzle according to the second aspect and a blower system, or by means of a blower system that is part of an apparatus according to a third aspect.

In particular, the blower system improves the cleaning process on the surface, since stains and leftover residues are removed.

The blower system might be a system working with compressed air (compressor blower) or with non-com- pressed air (leaf blower system).

In an advantageous embodiment, the system work ing with compressed air drives the droplets away from the surface with a pressure of 2 bar to 6 bar. The air flow is 5 1/s to 201/s, respectively 18m ³ /h to 72 m ³ /h. In partic ular, the blower moves the air with 60 m/s to 90 m/s over the surface to remove the stains and droplets. In a further advantageous embodiment, the sys tem works with non-compressed air, wherein the air flow is between 50 1/s and 1201/s, respectively 180 m3/h to 432 m3/h. In particular, the blower moves the air with 130 m/s to 500 m/s along the surface.

In an advantageous embodiment of the blower system, a longitudinal axis of the blower is inclined from the vertical of the surface by an angle y, wherein 10° > g > 40°, in particular if a compressor system is used. In a further advantageous embodiment, the angle g is 90° > g > 70°, in particular for a leaf blower system.

In an advantageous embodiment, the blower is coupled to a dirt guidance/direction management in partic ular controlled by the controller of the nozzle assembly.

In a further advantageous embodiment of the invention, the vision module comprises at least a number of n cameras, with 64 > n > 8, in particular with 48 > n > 12. Advantageously, one or more of the cameras are combined optical and infrared cameras. Further advantageously, one or more of the cameras are stereo cameras.

In a further advantageous embodiment of the invention, the one or more cameras are arranged within a shortest distance of 0.5m to 3m, in particular of 0.5m to 2m to the vehicle surface.

In a further advantageous embodiment of the invention, the surface data is a point cloud calculated from the scanning data.

In a further advantageous embodiment of the invention, the method comprises the step of calculating a mesh from the point cloud of the scanning data and of separating the mesh into individual surfaces.

In a further advantageous embodiment, the cleaning path can be calculated directly from the point cloud and the cleaning path for individual surfaces can be calculated directly from a CAD file or mesh that have been generated from a point cloud in advance. Advantageously, the scanned data might be ana lysed by means of a neuronal network to recognize the ve hicle model type (e.g. by means of recognizing colour, trademark, model type) and to compare the scanned surface data with pre-stored data of that vehicle model.

Further advantageously, the method comprises the step of cleaning the one or more of the individual surfaces by means of the nozzle.

In a further advantageous embodiment of the invention, the nozzle assembly comprises further a colli sion warning system or a collision avoidance system for preventing collisions with the vehicle surface.

Advantageously, the collision warning system comprises one or more collision radar or hard touch sensors or one or more lasers for distance measuring . The colli sion warning system thereby detects obstacles and gives a feedback to the controller to warn before an impending collision.

Advantageously, the collision avoidance system in case of a impending collision gives feedback to the calculation module and requests the calculation module to recalculate the cleaning path.

In a further advantageous embodiment, the robot arm that moves the nozzle comprises a 7-axis motor to al ternate the direction of discharging of the discharging steam and/or atomized liquid.

In a further advantageous embodiment of the invention, the method comprises the step of

- wetting the vehicle surface, in particular covering it with a mist of a liquid, in particular osmosis water,

- in particular, wherein the step of wetting the vehi cle surface is performed before scanning the vehicle surface,

- in particular wherein the step of wetting the vehi cle surface is performed by means of a mist produc ing device. In an advantageous embodiment, a mist system is integrated into the apparatus for producing the mist and covering the vehicle surface with the mist.

In a further advantageous embodiment of the invention, the vision module is adapted to recognize the type of vehicle by means of scanning the vehicle surface and matching the acquired surface data with vehicle sur face data pre-stored in a database.

Advantageously, the method comprises the steps of replacing the surface data with the pre-stored vehicle surface data and calculating the cleaning path from the pre-stored vehicle surface data.

In an alternative advantageous embodiment, the method comprises the steps of calculating the clean ing path from the surface data and the pre-stored vehicle surface data.

In a further advantageous embodiment, the method comprises the step of collecting residual liquid from the discharged steam/atomized liquid in a liquid tank adjacent to the vehicle holder.

An advantageous method for cleaning the vehi cle surface is adapted to use less than 20 litre of wa ter. The water is provided as steam or atomized water and by means of the nozzle is discharged towards the vehicles surface. The method performed according to the first as pect of the invention needs thereby less than 20 litres of water, wherein residual water might be collected and reused for cleaning a next vehicle.

In a second aspect, the invention refers to an apparatus for cleaning a vehicle according to the cleaning method of the first aspect.

The apparatus comprises:

- a vehicle holder adapted to hold a vehicle entering the apparatus,

- a nozzle assembly,

- a vision module, - a calculation module.

The nozzle assembly comprises:

- a robot arm adapted to move a nozzle according to a cleaning path,

- a nozzle adapted for discharging steam and/or atom ized liquid towards a vehicle surface and/or for blow drying of the surface, and

- a controller module for controlling the movements of the robot arm according to the cleaning path and for controlling the discharging of the nozzle.

In a further advantageous embodiment of the apparatus, the apparatus further comprises a liquid tank arranged adjacent to the vehicle holder, adapted to col lect the residual liquid discharged from the nozzle.

In a further advantageous embodiment of the invention, the apparatus further comprises rails for the robot arm to move within the apparatus. Advantageously, the apparatus further comprises a rail cover, for cover ing the rails.

A third aspect of the invention refers to a nozzle for the method according to the first aspect and comprised in the apparatus according to the second as pect.

The nozzle comprises a liquid passage adapted to direct a liquid stream in a downstream direction towards a liquid discharge or ifice, wherein the liquid discharge orifice is adapted to discharge the liquid stream into an expansion zone, a gas passage (12) adapted to direct a gas stream to wards a gas discharge orifice, wherein the gas discharge orifice is adapted to discharge the gas stream into the expansion zone. In an advantageous embodiment of the nozzle, the sum s of all areas of all orifices of the nozzle is 100mm ² > s ³ 0.5mm ² .

In a further advantageous embodiment of the invention, the nozzle discharge orifice has a diameter d _nozzie of 0.5mm < d _nozzie £ 2.00mm.

In a further advantageous embodiment of the invention, the atomized liquid is sprayed to the surface at the first end of the nozzle within a spray angle of 140° > a ³ 45°, in particular 120° > ³ 65°, very par ticular 100° > ³ 75°, very particular essentially 90°.

In a further advantageous embodiment of the invention, the atomized liquid is sprayed to the surface at the first end of the nozzle within a spray angle of 85°> a > 5°.

Other advantageous embodiments are listed in the dependent claims as well as in the description below.

Brief Description of the Drawings

The invention will be better understood and objects other than those set forth above will become ap parent from the following detailed description thereof. Such description makes reference to the annexed drawings, wherein:

Fig. la shows an embodiment of an apparatus for cleaning a vehicle according to a method for cleaning a vehicle;

Fig. lb shows a schematic picture of a method step according to an embodiment of the invention;

Fig. 2 a) and b) show schematics of a cleaning method according to embodiments of the invention;

Fig.2 c) shows an embodiment of a nozzle as sembly;

Fig. 3 a) and b) show embodiments of the noz zle according to experiment 1. Fig. 4 shows a photo picture of the result according to experiment 2;

Fig. 5 shows a photo picture of the result according to experiment 3; and

Fig. 6 shows a photo picture of the result according to experiment 4;

Modes for Carrying Out the Invention

Fig. la shows an embodiment of an apparatus for cleaning a vehicle with a method for cleaning a vehi cle.

The method for cleaning the vehicle surface 21 comprises an apparatus 1 comprising a holder 2 adapted to hold a vehicle, a nozzle assembly 3, a vision module 4, and a calculation module 5.

The nozzle assembly 3 comprises at least one nozzle 31, a robot arm 30, and a controller module 32.

The at least one nozzle 31 is adapted for discharging steam and/or an atomized liquid towards the vehicle sur face 21 and/or for blow drying.

The robot arm 30 is adapted to move at least one nozzle 31 according to a cleaning path.

The controller module 32 is adapted for con trolling the movements of the robot arm 30 according to the cleaning path and for controlling the discharging of the nozzle 31.

The method comprises the steps of

- scanning the vehicle surface (21) in the vehicle holder (2) by means of the vision module (4) to gain vehicle surface data,

- calculating the cleaning path from the vehicle sur face data provided by the vision module (4) by means of the calculation module (5), forwarding the cleaning path to the controller mod ule (32) of the nozzle assembly (3), - controlling the at least one nozzle (31) to follow the cleaning path and discharging steam and/or the atomized liquid and/or blow dry, for cleaning and/or drying the vehicle surface (21)

- directing the steam or atomized liquid to the vehi cle surface (21), wherein a shortest distance (d) between the surface (21) and a first end (311) of the nozzle (31) in downstream direction of the noz zle (31), is 1cm < d £ 20cm, in particular 1cm < d < 7cm, in particular 4cm < d £ 7cm

In an advantageous embodiment of the invention, the vision module 4 comprises at least a number of n cam eras, with 64 ³ n ³ 8, in particular with 48 ³ n ³ 12. Advantageously, one or more of the cameras are combined optical and infrared cameras. Further advantageously, one or more of the cameras are stereo cameras.

In a further advantageous embodiment of the invention, the one or more cameras are arranged within a shortest distance of 0.5m to 3m, in particular of 0.5m to 2m to the vehicle surface.

In a further advantageous embodiment of the invention, the surface data is a point cloud calculated from the scanning data.

In a further advantageous embodiment of the invention, the method comprises the step of calculating a mesh from the point cloud of the scanning data or from sections of the point cloud of the scanning data and of separating the mesh or the point cloud into individual surfaces or clusters.

In a further advantageous embodiment of the invention, the nozzle assembly 3 comprises further a col lision warning system 33 and/or a collision avoidance system, for preventing collisions with the vehicles sur face 21. In a further advantageous embodiment, as schematically shown in Fig. lb, the method comprises the step of

- wetting the vehicle surface, in particular covering it with a mist (shown as little droplets covering the vehicle surface) of a liquid, in particular os mosis water,

- in particular, wherein the step of wetting the vehi cle surface is performed before scanning the vehicle surface, in particular wherein the step of wetting the vehicle surface is performed by means of a mist producing device.

In an advantageous embodiment, a mist system 6 is integrated into the apparatus for producing the mist and covering the vehicle surface 21 with the mist.

Advantageously, the method as shown in Fig. la might comprise the step of directing the atomized liq uid to the vehicle surface 21, wherein a shortest dis tance d between the vehicle surface 21 and a first end of the nozzle 311 in downstream direction of the nozzle 31 is 1cm < d £ 5cm, in particular 1cm < d £ 4cm.

This method step is shown in Fig. 2 a) and b). Fig. 2 a) and b) show two different embodiments of nozzles 31 for performing the method of cleaning a vehi cle.

The method in Fig. 2 a) and b) comprises the steps of discharging a liquid, in particular with a pres sure of pi of lObar ³ pi ³ O.lbar, and a moisturized gas, in particular with a pressure p _g of 10 bar > p _g > O.lbar, into the expansion zone 13, for atomizing the liquid in the gas stream.

Advantageously, an impact temperature Ti of the atomized liquid is 80°C ³ Ti ³ 40°C, in particular 65°C ³ Ti > 40°C on impact on the surface. The steam or atomized liquid is directed to the surface 21, wherein a shortest distance d between the sur face 21 and a first end 311 of the nozzle 31 in downstream direction is 1cm < d £ 7cm, in particular 1cm < d £ 6cm.

The sum s of all areas of all orifices of the nozzle is 100mm ² > s ³ 0.5mm ² .

Advantageously, the gas is air moisturized with water with a moisture range h of lg/s ³ h ³ 0.01 g/s per nozzle. In particular, the term "per nozzle" refers to the discharging of the moisture mass in the gas passage re spectively discharging from the gas discharge orifice of the nozzle. Even if there are multiple gas passages in the nozzle 23, the air moisture range h is accumulated to re sult in the above-mentioned range.

Advantageously, the method further comprises the step of moving the first end 311 of the nozzle 31 with a velocity v _n of 5.00 m/s > v _n > 0.01 m/s, in particular of 1 m/s ³ v _n ³ 0.01 m/s, very particular 0.6 m/s ³ v _n ³ 0.01 m/s, in a lateral direction relative to the surface 21, as indicated by the arrow v _n . In particular, the first end 311 keeps the distance d when it is moved over the surface.

Advantageously, an angle b between a longitu dinal axis of the nozzle 31 and the surface plane is 90° ³ b ³ 30°, in particular 90° > b > 45°°, very particular 80° > b > 70°, very particular essentially 75°.

In Fig. 2 a), it is schematically shown how the method would work with a nozzle 31 according to a further embodiment of the nozzle 31.

In a further advantageous embodiment of the invention, the method would further comprise the step of blow drying the surface before the steam or the atomized liquid is directed towards the surface 21, or synchronous with directing the steam or atomized liquid to the sur face 21. The first end 311 of the nozzle 21 in Fig. 2 a) is forming a first end discharge orifice for discharg ing the steam or atomized liquid. The steam or atomized liquid is sprayed to the surface 21 at the first end 311 of the nozzle within a spray angle a, 120° > a ³ 5°, in particular of 85° > ³ 5°, in particular 55° > ³ 15°, very particular 50° > ³ 25°, very particular essen tially 45°.

In a further advantageous embodiment of the invention, the atomized liquid is sprayed to the surface (2) at the first end (101) of the nozzle (1) within a spray angle of 140° > a ³ 45°, in particular 120° > ³ 65°, very particular 100° > ³ 75°, very particular es sentially 90°.

In a further advantageous embodiment of the invention, the atomized liquid is sprayed to the surface (2) at the first end (101) of the nozzle (1) within a spray angle of 85°³ a ³ 5°.

As described above for Fig. 2, the first end 311 of the nozzle 31 in Fig. 2 b) corresponds to the steam or atomized liquid discharge orifice. The steam or atom ized liquid that discharges from the nozzle is sprayed to the surface 21 at the first end 311 of the nozzle 31 that corresponds essentially to the steam or atomized liquid discharge orifice 311, within a spray angle a.

In a further advantageous method according to an embodiment of the invention, multiple nozzles 31 ac cording to the embodiment of Fig. 2 might be used to clean a surface 21. The individual nozzles might clean one sur face 21 at the same time or might clean different surfaces at the same time, e.g. different surfaces of one vehicle.

Fig. 2c shows a section of a nozzle assembly of a nozzle 31 and a blower system 35 of an apparatus 1 according to an embodiment of the invention, comprising a blower 35 and the atomising nozzle 31. Advantageously, the blow drying of the surface 21 is achieved by means of a blower system 35 that is part of the nozzle assembly 3 or part of the apparatus 1.

In particular, the blower system 35 improves the cleaning process on the surface 21, since stains and leftover residues are removed.

The blower system 35 might be a system working with compressed air (compressor blower) or with non-com- pressed air (leaf blower system).

In an advantageous embodiment of the blower system, a longitudinal axis of the blower is inclined from the vertical of the surface by an angle y, wherein 10° > g > 40°, in particular if a leaf blower system is used. In a further advantageous embodiment, the angle g is 90° > g > 70°, in particular for a compressor blower.

Experiments

Experiment 1: Fig. 3a and Fig. 3b disclose embodiments of nozzles that might be used for the appa ratus. Both embodiments disclose nozzles for atomizing a liquid, in particular water.

Each of the nozzles shown in Fig. 3a and Fig. 3b show the following features:

The nozzle comprises a liquid passage 1011 adapted to direct a liquid stream in a downstream direction towards a liquid discharge orifice 10111. In particular, the liquid passage 1011 extends along a longitudinal axis 10100 of the nozzle 101 and terminates downstream of the liquid passage 1011 in a in particular circular liquid discharge orifice 10111. The downstream direction in Fig. 3a and Fig. 3b is indicated by the arrow ds, but is also clear from the description.

In addition, the nozzle comprises a gas passage 1012 adapted to direct a gas stream towards an in partic ular annular gas discharge orifice 10121, wherein the gas discharge orifice 10121 is adapted to discharge the gas stream into the expansion zone 1013. In particular, the gas discharge orifice 10121 is arranged coaxially to the liquid discharge orifice 10111.

In the embodiment of Fig. 3a, the liquid pas sage 1011 and the air passage 1012 end within the nozzle body. Therefore, the liquid discharge orifice 10111 and the gas discharge orifice 10121 are arranged within the body of the nozzle. The liquid discharge orifice 10111 and the gas discharge orifice 10121 are arranged at the same level in a downstream direction of the longitudinal axis 10100 of the nozzle.

The expansion zone 1013 is therefore also ar ranged within the nozzle 101. The first end 10101 of the nozzle 101 encloses the expansion zone 1013 and forms a nozzle discharge orifice for discharging the atomised liq uid. In particular, the first end 10101 of the nozzle 101 is arranged after the gas discharge orifice 10121 and after the liquid discharge orifice 10111 and after the expansion zone 1013 in a downstream direction of the longitudinal axis 10100 of the nozzle 101.

In particular, the nozzle discharge orifice has a diameter d _n0 zzie of 0.5mm < d _n0 zzie£ 2.00mm.

In Fig. 3b, the liquid passage 1011 and the gas passage 1012 end in particular at the same level as the first end 10101 of the nozzle 101. The expansion zone 1013 is therefore located outside the nozzle 101. In Fig. 2, the liquid discharge orifice 10111 and the gas discharge orifice 10121 are arranged on the same level in downstream direction of the longitudinal axis 10100.

In particular, the first end 10101 of the noz zle corresponds to the liquid discharge orifice 10111.

In particular, the first end 10101 of the noz zle 101 is arranged at the same level in a downstream direction of the longitudinal axis 10100 as the liquid discharge orifice 10111 and the gas discharge orifice 10121. Experiment 2: Fig. 4 shows a photo picture of a surface that was cleaned with a method according to an embodiment of the invention. The picture shows a good to excellent result that was achieved by cleaning the sur face with the parameters:

^■ Mass flow of water ni _f = 0.0067 kg/s, 65°C

^■ Mass flow of air m _g = 0.0033 kg/s, 80°C

^■ Amount of the water additive h to the heated air =

(+ 0.33 g/s water),

^■ The impact temperature Ti of the atomized droplets at surface was 50 °C at a distance d of nozzle 1 at (3 cm). (According to Table 1 No 5)

The surface in Fig. 4 comprises brighter lines LI and L2. The lines LI and L2 are areas where the nozzle was moved laterally to the surface with a distance of essentially 3 cm between the end of the nozzle and the surface.

Experiment 3: Fig. 5 shows a photo picture of a surface that was cleaned with a method according to an embodiment of the invention. The picture shows a result that was achieved by cleaning the surface with the param eters:

^■ volume flow of water 0.31/h - 0.51/h

^■ The impact temperature Ti of the atomized droplets at surface was 45°C to 50 °C at a distance d of nozzle 1 at (6 cm).

The surface in Fig. 5 comprises brighter lines. The lines L3 and L4 are areas where the nozzle was moved laterally to the surface with a distance of essen tially 6 cm between the end of the nozzle and the sur face. It is very well visible that the cleaning lines have a width clw of are ca. 3cm.

In conclusion, the cleaning method works very well, even if the distance between the vehicle surface and the end of the nozzle is d ³ 5. The large distance d results in the fact that a larger area can be cleaned at once and therefore the process to clean the whole vehi cles is accelerated.

Experiment 4: Fig. 6 shows a photo picture of a surface that was cleaned with a method according to an embodiment of the invention with a steam nozzle using steam. The picture shows a result that was achieved by cleaning the surface with the parameters:

^■ volume flow of water 0.31/h - 0.51/h

^■ The impact temperature Ti of the atomized droplets at surface was 45°C to 50 °C at a distance d of nozzle 1 at (3 cm).

The surface in Fig. 6 comprises brighter lines. The lines L5 and L6 are areas where the nozzle was moved laterally to the surface with a distance of essen tially 3 cm between the end of the nozzle and the sur face. It is very well visible that the cleaning lines have a width clw of are ca. 2cm. In conclusion, the cleaning method works very well, with a nozzle discharging either steam or atomized liquid with 20cm > d ³ 1cm, in particular with 10cm > d ³ lcm.