Systems and methods for fluid dispersion - Patents.com

Abstract

1. A fluid distribution system (1) for a vehicle, adapted to supply fluid to a plurality of fluid nozzles (6, 8), comprising: a fluid reservoir (2) arranged to hold a fluid; an accumulator tank (3) arranged to hold a pressurized fluid; a pump (4) arranged to supply pressurized fluid to the accumulator tank (3); a first type of fluid nozzle (8) having a controllable valve (9) connected to the accumulator tank (3); and an electronic control unit (7) arranged to control the pump (4) and the controllable valve (9), wherein the pump (4) further comprises a controllable backflow valve (5) connected to a windshield washer nozzle (6), the backflow valve (5) being closed as a default, and the electronic control unit (7) being arranged to open the backflow valve (5) of the pump (4) in response to an open signal.

Description

[Technical field]

[0001] The present invention relates to a system and method for fluid distribution in a vehicle, preferably for an autonomous vehicle having multiple sensors, at least some of the sensors comprising fluid nozzles, that reduces the amount of components used in such systems. [Background technology]

[0002] Vehicles are becoming equipped with more and more sensors arranged to detect objects in the vehicle's immediate vicinity. Some sensors are arranged to increase the safety of the vehicle, for example to measure the distance to the vehicle ahead of the vehicle or to detect if the vehicle is approaching a lane side line. Other sensors are used to provide a detailed view of the vehicle's surroundings, giving the vehicle a certain degree of autonomy, so that the vehicle can drive autonomously on at least a portion of the road.

[0003] Some of these sensors, for example cameras, require a clear view to be able to give a clear signal that is useful to the control system. Therefore, to provide reliable functioning, the sensors must not be contaminated or dirty. For this reason, vehicles are equipped with a washing system arranged to wash the sensor when necessary. In most cases, a washing fluid, such as water or windshield washer fluid, is used to wash the sensor, a nozzle being placed close to the sensor. Similar to a headlamp washing system in a vehicle, a pressurized fluid is sprayed at high pressure onto the sensor so that contamination or dirt is removed from the sensor.

[0004] To reduce the amount of components and the cost of the system, each sensor nozzle does not have its own pressure pump. Instead, each sensor nozzle has a controllable valve that can open when fluid is to be sprayed onto the sensor. Fluid to the nozzles is provided from a pressurized accumulator tank that provides fluid at a sufficiently high pressure. The vehicle includes at least one pressurized accumulator tank and may include multiple pressurized accumulator tanks, depending on, for example, the layout of the washer system. Pressurized fluid to the pressurized accumulator tank is provided using a pressure pump connected to a fluid reservoir, such as, for example, an existing container that holds the vehicle's windshield washer fluid. Windshield washer fluid to the windshield nozzles is provided using a dedicated windshield pump located in or near the fluid reservoir.

[0005] The problem of cleaning additional sensors is well known.

[0006] EP 3 615 391 B1 discloses a cleaning system including a pressure reservoir, where all fluid nozzles of the vehicle are supplied with pressurized fluid from the pressure reservoir via separate controllable valves. The pressurized fluid is supplied to the pressure reservoir by a high pressure pump.

[0007] US2020 / 0180567A1 discloses a cleaning system in which a pump supplies pressurized fluid to a number of nozzles, each nozzle having a controllable valve that is opened when the nozzle requires fluid.

[0008] Although these systems work well, there is still room for improvement in washing systems for vehicles. Summary of the Invention

[0009] It is therefore an object of the present invention to provide a fluid distribution system for a vehicle. It is a further object of the present invention to provide a method for distributing a fluid on a vehicle. It is a further object of the present invention to provide a vehicle including such a system. It is also an object to provide a computer program and a computer program product adapted to carry out the steps of the method.

[0010] The solution to the problem according to the invention is set out in the characterising parts of claim 1 for the system, claim 10 for the method and claim 13 for the vehicle. The other claims contain advantageous further developments of the inventive system and method. Claims for computer programs and computer program products are also included.

[0011] In the fluid distribution system for a vehicle of the present invention adapted to supply fluid to a plurality of fluid nozzles, the system includes a fluid reservoir arranged to hold a fluid, an accumulator tank arranged to hold a pressurized fluid, a pump arranged to supply pressurized fluid to the accumulator tank, a first type of fluid nozzle having a controllable valve connected to the accumulator tank, and an electronic control unit arranged to control the pump and the controllable valve, the object of the present invention is achieved in that the pump further includes a controllable backflow valve connected to the windshield washer nozzle, the backflow valve being closed as a default, and the electronic control unit is arranged to open the backflow valve of the pump in response to an open signal.

[0012] The system of the present invention provides a washing system for a vehicle. The vehicle may be an autonomous vehicle with a level of driving automation, for example, level 2, 3, or 4. The higher the level of automation, the more sensors are used in the vehicle. In the system, the windshield nozzle is supplied with fluid from a pressurized accumulator tank through a controllable backflow valve in the pump, and the sensor nozzle is supplied with fluid from the pressurized accumulator tank through a controllable valve connected to the sensor nozzle. In this way, there is no need for a separate controllable valve for the windshield nozzle, which simplifies the system. In one example, the headlights may also be supplied with fluid from the backflow valve. That is, the headlamp nozzle may be connected in parallel to the windshield nozzle.

[0013] The pump is connected to a fluid supply reservoir, for example a windshield washer tank, in which the cleaning fluid is stored. The fluid reservoir is usually vented and has ambient pressure. The pump is preferably a high-pressure pump, providing a pressure of 5-10 bar and a flow rate of at least 2 liters / min. The pump supplies pressurized fluid to a pressurized accumulator tank. Each sensor nozzle is connected to a pressurized accumulator tank. In this way, each sensor nozzle must not be supplied by a separate pump. Each nozzle or group of nozzles comprises a controllable valve that opens when the nozzle should spray cleaning fluid on the sensor. The controllable valve is preferably located close to the pressurized accumulator tank. This reduces the idle pressure in the pressure line connecting the pressurized accumulator tank to the nozzle.

[0014] A pressure sensor located at the pump outlet or in the pressurized accumulator monitors the pressure in the pressurized accumulator and activates the pump when the pressure falls below a predetermined value. In this way, the pressurized accumulator can constantly deliver pressurized fluid to the sensor nozzle and to the windshield nozzle.

[0015] The windshield nozzle is connected to a controllable backflow valve installed in the pump or in the supply line to the pump. The backflow valve is arranged as an overpressure valve that opens at a predefined pressure to protect the pressurized accumulator tank from overpressure. The backflow valve can also be controlled by the electronic control unit to open at other pressure values. The backflow valve is used to supply washing fluid to the windshield nozzle. When the driver wants to wash the windshield, the driver presses the washer button and the ECU opens the backflow valve so that washing fluid is supplied to the windshield nozzle. By using an existing controllable backflow valve, the system is simplified.

[0016] The fluid reservoir may also be an airtight container that is pressurized by an external pressure source, for example from a vehicle compressor. In this way, the fluid reservoir may be pressurized at a low pressure, for example 2 bar, so that the pump only has to raise the pressure level to a lesser extent.

[0017] A method of distributing pressurized fluid to a first fluid nozzle type and a second fluid nozzle type on a vehicle, where the first type fluid nozzle is connected to an accumulator tank via a controllable valve and the second type fluid nozzle is connected to the accumulator tank via a controllable check valve in a pump, includes the steps of supplying pressurized fluid from a fluid reservoir to the accumulator tank with the pump, opening the controllable valve to supply pressurized fluid to the first type fluid nozzle when a first signal is issued, and opening the check valve in the pump to supply pressurized fluid to the second type fluid nozzle when a second signal is issued.

[0018] This first embodiment of the method allows cleaning of various sensors without the need for multiple pressure pumps. By using the existing controllable backflow valves of the pressure pumps, a simplified cleaning system is obtained.

[0019] The invention will now be described in more detail with reference to the accompanying drawings. [Brief description of the drawings]

[0020] [Figure 1] 1 shows a schematic example of a vehicle equipped with a fluid distribution system. [Diagram 2] 1 shows a schematic example of a fluid dispersion system. [Diagram 3] 1 shows a schematic flow chart of the method of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The embodiments of the invention together with further developments described below should be regarded as examples only and in no way limit the scope of protection provided by the claims.

[0022] Figure 1 shows a schematic vehicle 20 equipped with the inventive system 1, and Figure 2 shows the inventive system for vehicle fluid distribution, where the system is adapted to supply pressurized washing fluid to a number of nozzles. In this way, the windshield can be washed as normal and the windshield pressure pump can be used to pressurize an accumulator tank arranged to supply pressurized fluid to the sensor nozzles. The controllable valves are controlled by an electronic control unit (ECU) so that selected sensors can be washed when required.

[0023] The system 1 includes a fluid reservoir 2 arranged to hold washer fluid, preferably a conventional windshield washer reservoir. The reservoir may hold, for example, 4-10 liters or more of washer fluid. The fluid reservoir is, in one example, vented, i.e., at ambient pressure. The system further includes a pressure accumulator tank 3 arranged to hold pressurized fluid. Pressurized fluid is provided from the fluid reservoir by a pressure pump 4, such as, for example, a conventional windshield washer pump. The pressure pump is selected such that the pressure and volume meet the needs of the vehicle.

[0024] Typically, the windshield pump is controlled to deliver pressurized washing fluid when the wiper washer lever is operated by the driver. Here, the pump is controlled by the ECU to deliver pressurized fluid to a pressurized accumulator tank 3. The pressure in the pressurized accumulator tank is kept in a predetermined pressure range, for example between 6-8 bar. A pressure sensor is used to measure the pressure in the pressurized accumulator tank 3. The pressure sensor may be a pressure sensor 10 located in the pump and measuring the outlet pressure of the pump. The pressure sensor may also be a pressure sensor 11 located in the pressurized accumulator tank and measuring the pressure in the tank.

[0025] The pressure pump 4 is equipped with a controllable backflow valve 5. The backflow valve is arranged to open at a predefined high pressure to protect the washing system from overpressure. The predefined pressure may be set to, for example, 10 or 12 bar, higher than the desired operating pressure of the system. The backflow valve is also controllable by the ECU to be able to release pressure from the system if required for other reasons or at other pressure levels. Here, the controllable backflow valve is also used to supply the washing fluid to the windscreen washer nozzles.

[0026] The system includes a first type of nozzle 8 arranged to wash different sensors of the vehicle. The sensors may include radar sensors, cameras 13, laser sensors 14, infrared sensors, ultrasonic sensors or any other sensors whose signal is impaired by a dirty sensor surface. The intervals between washing of the sensors may be determined, for example, by estimates for the input signal or by inputs from other sensors, for example from a rain sensor. It is also possible to wash the sensors at given time intervals or, for example, when the windscreen wipers are used.

[0027] The first type of nozzle 8 is connected to the pressurized accumulator tank via a controllable valve 9. The controllable valve is preferably arranged close to the pressurized accumulator tank 3. In this way, the pressure line between the controllable valve and the nozzle is not subjected to a constant high pressure, which reduces the risk of leakage and simplifies the system. Several nozzles can be supplied with cleaning liquid via the same controllable valve.

[0028] The system also includes a second type of nozzle, which is one or more windshield washer nozzles 6, connected to the pump's backflow valve 5. By opening the backflow valve, fluid can flow from the pressurized accumulator tank through the pump and the backflow valve to the windshield nozzles 6, which spray washing fluid onto the windshield 12. It is also possible to connect a headlight nozzle in parallel with the windshield nozzle. The backflow valve is closed as a default and can be opened by a signal from the wiper washer lever when operated by the driver, which sends a signal to the ECU to open the backflow valve.

[0029] In one example, the fluid reservoir may also be an airtight container pressurized by an external pressure source, for example from a compressor of the vehicle. In this way, the fluid reservoir may be pressurized at a low pressure, for example 2-4 bar. In this way, the operating time of the pump may be reduced. The external pressure may be provided, for example, by an existing compressor of the vehicle.

[0030] To balance the system so that the required pressure and volume of fluid is used to flush each nozzle and therefore each sensor, some pressure lines may be equipped with restriction means to reduce the pressure and / or volume in that pressure line. In this way, the same pressurized accumulator tank can be used for different types of nozzles and sensors.

[0031] 3 shows a schematic flow chart of an example of a method for distributing pressurized fluid to a first fluid nozzle type and a second fluid nozzle type on a vehicle. A first type of fluid nozzle, here a sensor nozzle, is connected to the accumulator tank via a controllable valve. A second type of fluid nozzle, here a windshield washer nozzle, is connected to the accumulator tank via a controllable backflow valve in a pump.

[0032] At step 100, pressurized fluid is supplied from a fluid reservoir to an accumulator tank using a pressure pump.

[0033] In step 110, it is determined whether a first signal has been issued, the first signal being a signal to open a controllable valve to supply pressurized fluid from a pressurized accumulator tank to a first type of fluid nozzle. If the first signal has been issued, the controllable valve is opened in step 120. If the first signal has not been issued, the method continues to step 130. The first signal may be issued by an autonomous control system of the vehicle, for example, depending on climatic or environmental inputs such as temperature, humidity, etc.

[0034] At step 130, it is determined whether a second signal is issued, the second signal being a signal to open the pump's controllable backflow valve to supply pressurized fluid from the pressurized accumulator tank to the second type of fluid nozzle. If the second signal is issued, the controllable backflow valve is opened at step 140. If the second signal is not issued, the method returns to step 110 and the method steps are repeated. The second signal may be issued by a driver of the vehicle when a windshield wiper lever is operated.

[0035] The invention should not be considered limited to the above-described embodiments, several further variations and modifications are possible within the scope of the following claims. [Explanation of symbols]

[0036] 1: Fluid dispersion system 2: Fluid reservoir 3: Accumulator tank 4: Pump 5: Controllable backflow valve 6: Windshield washer nozzle 7: Electronic control unit 8: Fluid nozzle 9: Controllable valve 10: Pump pressure sensor 11: Tank pressure sensor 12: Windshield 13: Camera 14: Rider 20: Vehicle

Claims

1. 1. A fluid distribution system (1) for a vehicle, comprising: a fluid reservoir (2) arranged to hold a fluid; an accumulator tank (3) arranged to hold a pressurized fluid; a pump (4) arranged to supply pressurized fluid to the accumulator tank (3); a first type of fluid nozzle (8) with a controllable valve (9) connected to the accumulator tank (3); and an electronic control unit (7) arranged to control the pump (4) and the controllable valve (9), adapted to supply the fluid to a plurality of fluid nozzles (6, 8), characterized in that the pump (4) further comprises a controllable backflow valve (5) connected to a windshield washer nozzle (6), the backflow valve (5) being closed as a default, and the electronic control unit (7) being arranged to open the backflow valve (5) of the pump (4) in response to an opening signal.

2. The system of claim 1 , wherein the fluid nozzle (8) comprises a fluid restrictor arranged to restrict the flow of the fluid through the nozzle (8).

3. 3. The system according to claim 1 or 2, wherein the fluid reservoir (2) is a vented reservoir having ambient pressure.

4. 3. The system according to claim 1 or 2, wherein the fluid reservoir (2) is an airtight reservoir arranged to be pressurized from an external pressure source.

5. The system according to any one of the preceding claims, wherein the pump (4) is provided with a pressure sensor (10) at the outlet of the pump (4).

6. The system according to any one of claims 1 to 4, wherein the accumulator tank (3) is provided with an internal pressure sensor (11).

7. A vehicle (20) comprising a system according to any one of the preceding claims.

8. 1. A method for distributing pressurized fluid to a first fluid nozzle type and a second fluid nozzle type on a vehicle, the first type fluid nozzle being connected to an accumulator tank via a controllable valve and the second type fluid nozzle being connected to the accumulator tank via a controllable check valve in a pump, the method comprising: - supplying pressurized fluid from a fluid reservoir to the accumulator tank using the pump; - when a first signal is issued, opening a controllable valve to supply pressurized fluid to said first type of fluid nozzle; - when a second signal is issued, opening the backflow valve of the pump to supply pressurized fluid to the second type of fluid nozzle; The method comprising:

9. The method of claim 8 , wherein the first type of fluid nozzle is a sensor spray nozzle.

10. The method of claim 9 , wherein the sensor is a radar sensor, a camera, a laser sensor, an infrared sensor, or an ultrasonic sensor.

11. The method according to any of claims 8 to 10, wherein the second type of fluid nozzle is a windscreen washer nozzle.

12. The method according to any one of claims 8 to 11, wherein the first signal is issued by an autonomous control system of the vehicle.

13. The method according to any one of claims 8 to 12, wherein the second signal is issued by a driver of the vehicle.

14. A computer program comprising program code means, said program code means comprising program code means for performing all the steps of claims 8 to 13 when said program is run on a computer.

15. A computer program product comprising program code means, said program code means being stored on a computer readable medium for performing all the steps of claims 8 to 13 when said program product is run on a computer.

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