CN110753817A

CN110753817A - Method for venting at least one pressure vessel and pressure vessel system

Info

Publication number: CN110753817A
Application number: CN201880038028.0A
Authority: CN
Inventors: S·黑滕科费尔
Original assignee: Bayerische Motoren Werke AG
Current assignee: Bayerische Motoren Werke AG
Priority date: 2017-07-05
Filing date: 2018-06-13
Publication date: 2020-02-04
Anticipated expiration: 2038-06-13
Also published as: CN110753817B; DE102017211474A1; WO2019007654A1

Abstract

The technology disclosed herein relates to a method for venting at least one pressure vessel (100) and a pressure vessel system. The method comprises the following steps: i) detecting a pre-crash condition; and ii) taking protective action on the pressure vessel (100) if a pre-crash condition is detected.

Description

Method for venting at least one pressure vessel and pressure vessel system

Technical Field

The technology disclosed herein relates to a method for venting at least one pressure vessel. Further, the technology disclosed herein relates to a pressure vessel system for a motor vehicle.

Background

Pressure vessel systems for motor vehicles are known per se. Furthermore, thermal safety valves (TPRD) are known from the prior art. In the event of a thermal event, the thermal safety valve vents the pressure vessel to thereby avoid a sudden burst of the pressure vessel.

Disclosure of Invention

A preferred task of the technology disclosed herein is to reduce or eliminate at least one of the drawbacks of the previously known solutions or to propose alternative solutions. A preferred task of the technology disclosed herein is, in particular, to make the pressure relief particularly safe, preferably without thereby seriously adversely affecting the structural space requirement, the production costs and/or the weight. Other preferred tasks may be given by the benefits of the techniques disclosed herein. The object is achieved by the solution of the independent claims. The dependent claims are preferred embodiments.

The technology disclosed herein relates to a method for venting at least one pressure vessel of a motor vehicle. The method comprises the following steps:

-detecting a pre-crash condition; and is

-venting said at least one pressure vessel (100) if a pre-crash situation is detected.

A pre-crash situation is a situation in which an imminent collision of a running motor vehicle with another stationary or moving object, such as another vehicle, is predicted. Such a pre-crash situation is identified, for example, if an imminent crash is predicted with sufficient probability before the actual crash. That is, the prediction here occurs before the motor vehicle collides or comes into contact with the object.

In principle, so-called pre-crash systems are known in motor vehicles, which are able to detect a pre-crash situation. Attempts are made with such systems to prevent accidents or to mitigate their consequences. For this purpose, for example, data of an environment recognition system of the motor vehicle can be used. Advantageously, the environment recognition system here comprises one or more of the following components: an ultrasonic sensor, a radar sensor, a lidar device, and/or a camera device. Any other system configured for sensing the environment of a motor vehicle may be used as well. Any other system configured for sensing the environment of a motor vehicle may be used as well. The wirelessly transmitted data can be provided, for example, by a computing unit outside the motor vehicle, which evaluates the position of the motor vehicle and other objects and correlates them with one another. The pre-crash system may also process data from at least one external computing unit to detect a pre-crash condition. In addition, the location data may be provided by a GPS system or used for calculation and verification.

The technology disclosed herein relates to pressure vessel systems for automotive vehicles (e.g., cars, motorcycles, trucks). Pressure vessel systems are used to store fuels that are gaseous at ambient conditions. Pressure vessel systems can be used, for example, in motor vehicles which are operated by means of Compressed Natural Gas (CNG) or Liquefied Natural Gas (LNG) or by means of hydrogen.

The pressure vessel system includes at least one pressure vessel. The pressure vessel may be, for example, a low-temperature pressure vessel (CcH 2) or a high-pressure gas vessel (CGH 2).

The high-pressure gas container is designed to store fuel at approximately ambient temperature and continuously at a nominal operating pressure (also referred to as nominal operating pressure or NWP) of approximately 350 bar (overpressure relative to atmospheric pressure), more preferably approximately 700 bar or more. The cryogenic pressure vessel is adapted to store fuel at the operating pressure also described above at temperatures well below the operating temperature of the vehicle.

The pressure relief can preferably be performed by at least one pressure relief device of the pressure vessel system. The pressure relief is preferably performed by activating a pressure relief device. The pressure in the pressure vessel system, in particular in the at least one pressure vessel, is reduced by pressure relief when a failure occurs due to a failure of other components and/or due to external thermal and/or mechanical effects, such as an accident, a local flame, etc. The fuel discharge mass flow can be adjusted at the pressure vessel venting, which is greater (e.g., by at least a factor of 1.5, 2, 5, 10, 100, or more) than the maximum fuel discharge mass flow through the discharge path to the at least one energy converter (typically through the tank shut-off valve). The at least one pressure relief device is typically not used for filling the pressure vessel system and/or for extracting fuel in order to provide energy during fault-free operation of the motor vehicle. Suitably, the pressure relief may be performed using a flow path parallel to the anode sub-system. Typically, the pressure inside the pressure vessel is reduced to atmospheric pressure by venting.

The pressure relief device may comprise, for example, at least one overpressure valve and/or at least one thermally activatable pressure relief device.

A thermally activatable pressure relief device (also referred to as a thermal pressure relief device or TPRD) is typically disposed adjacent the pressure vessel. Under the action of heat (e.g., due to a flame), the TPRD expels the fuel stored in the pressure vessel to the environment. As soon as the trigger temperature of the TPRD is exceeded (thermal activation), the pressure relief device discharges the fuel. Furthermore, a trigger line may be provided. Such systems for thermal decompression are shown, for example, in DE102011114725 a1 or EP 1655533B 1.

The overpressure valve unloads the pressure vessel system if the pressure in the pressure vessel system is at least locally higher than the trigger pressure of the overpressure valve. Preferably, the overpressure valve is a mechanical valve, which can be opened and closed again. The trigger pressure is greater than the maximum operating pressure, for example, about 10% to about 20% greater than the maximum operating pressure. The overpressure valve is in particular designed such that it is usually triggered before an excessively high pressure can damage components of the pressure vessel system.

Preferably, the at least one pressure relief device may be electrically openable. Preferably, the pressure relief device is an electrically valve-closed-off-less device. For this purpose, a solenoid can be provided in the pressure relief device, which opens an otherwise usually mechanically actuated closing mechanism of the pressure relief device. Other embodiments are also contemplated.

The system disclosed herein also includes at least one controller. The controller is configured, inter alia, to perform the method steps disclosed herein. To this end, the controller can at least partially and preferably completely regulate (closed-loop control) or control (open-loop control) the actuators of the system on the basis of the signals provided. The controller may affect at least the cooling system of the fuel cell system, in particular the cathode subsystem, the anode subsystem and/or the fuel cell system. Alternatively or additionally, the controllers can also be integrated together in a further controller, for example a superordinate controller. The controller may interact with other controllers of the vehicle.

In particular, the controller may be configured to detect a pre-crash condition. Further, the controller may be configured to take further protective action with respect to the pressure vessel based on the signal indicative of the pre-crash condition. Preferably, the at least one controller is configured to send a signal to the pressure relief device, whereupon the pressure relief device begins to relieve pressure.

The technology disclosed herein also relates to a tank cut-off valve. A tank shut-off valve is a valve whose inlet pressure is (substantially) equal to the vessel pressure. The tank shut-off valve is in particular a controllable or adjustable and in particular no normally closed valve. Tank shut-off valves are usually integrated into on-tank valves (═ OTVs). The on-tank valve is a valve unit mounted directly at one end of the pressure vessel and in direct fluid communication with the interior of the pressure vessel. In commission regulation (EU) for executing regulation (EG)79/2009 of european parliament and council about approval of hydrogen-powered vehicle model, No. 406/2010 on 26 th 4/2010, this tank shutoff valve is also referred to as a first valve.

The pressure vessel system disclosed herein may also have at least one self-contained energy supply device that is independent of other energy storage devices of the vehicle, such as a high voltage battery. Such a self-contained energy supply device may be configured to provide electrical energy to the at least one controller, the at least one pressure relief device, and/or the tank shut-off valve. Therefore, the pressure relief disclosed herein can advantageously also be carried out in the event of a crash damage to the on-board electrical system of the motor vehicle.

According to the methods disclosed herein, a value may be determined that is directly or indirectly indicative of a degree of damage to the motor vehicle and/or pressure vessel caused by the collision. This value may take into account, for example, the relative velocity between the oncoming objects. Further, the value may take into account the predicted impact energy.

The methods disclosed herein may include the steps of: venting the at least one pressure vessel if the determined value indicates or predicts damage to the motor vehicle and/or the pressure vessel and if the damage is associated with a structural failure of a component of the at least one pressure vessel. In other words, the pressure relief is carried out if the indicator value predicts, at least with a certain probability, a structural failure of a component of the pressure vessel. For this purpose, the indicator value can be compared, for example, with a threshold value or a characteristic map which indicates the degree of damage associated with a structural failure (e.g., a burst) of a component of the pressure vessel. Pressure relief may be performed, in particular, if the impact on the at least one pressure vessel based on the predicted impact is at least likely to occur in a pressure vessel burst event.

The methods disclosed herein may further comprise the steps of: if the determined value indicates or predicts a damage unrelated to a structural failure of a component of the at least one pressure vessel, the at least one pressure vessel is not vented in the event of a pre-crash. In other words, the method disclosed herein may comprise the steps of: the degree of impending damage is predicted and whether to vent is determined based on the degree of damage. If the vehicle and object collide only at a low speed, such as in a parking collision accident or slow moving traffic, such collisions do not affect the pressure vessel. For this purpose, sufficient crumple zones are provided in the motor vehicle, which absorb the impact energy. In which case no pressure relief is required. If it is predicted that the vehicle will inevitably collide at high speed, even with a large energy removal section, the mechanical influence on the pressure vessel cannot always be avoided. In which case the pressure relief may have been initiated early in accordance with the methods disclosed herein to reduce the likelihood of a burst event. In the event of a failure of the controller or the system, the system is preferably kept in a safe state and preferably no pressure relief is performed.

The methods disclosed herein may include the steps of: if a pre-crash condition is detected, the tank shut-off valve is closed. In particular, the tank shut-off valve may be closed when the determined value indicates damage unrelated to a structural failure of a component of the at least one pressure vessel. Structural damage to the pressure vessel can often already be avoided before the collision. At the same time, however, there may still be a risk of the fuel supply lines of the anode sub-system breaking or at least leaking on the basis of mechanical action. In this case it may be advantageous if the tank shut-off valve is already closed at this time. Thereby preventing or reducing unnecessary fuel outflow.

In a preferred embodiment, the at least one energy converter can increase the fuel consumption after a pre-crash situation is detected, so that the amount of fuel in the fuel supply line is reduced when the tank valve is closed. Less fuel can thereby be released in the event of a pipe break.

The technology disclosed herein also relates to at least one energy converter. The energy converter is configured to convert the chemical energy of the fuel into other energy forms, such as electrical energy and/or kinetic energy. The energy converter may be, for example, an internal combustion engine or a fuel cell system having at least one fuel cell. Suitably, the fuel cell system comprises an anode sub-system, which anode sub-system is constituted by the fuel delivery components of the fuel cell system. The anode subsystem may include at least one pressure vessel, at least one tank shut-off valve, at least one pressure reducer, at least one anode inflow path to the anode inlet of the fuel cell stack, an anode volume in the fuel cell stack, at least one recirculation flow path away from the anode outlet of the fuel cell stack, at least one water separator (AWS), at least one anode purge valve, at least one active or passive fuel recirculation transporter, and other elements. The main task of the anode subsystem is to introduce and distribute fuel to the electrochemically active surface of the anode chamber and to exhaust the anode exhaust gas.

In other words, the technology disclosed herein relates to a pressure relief system. The system may include an electronic pressure relief valve (with separate self-contained power supply if necessary) that can be actively opened. The distance and speed of another traffic participant can be detected in conjunction with existing sensor means for automatic driving, such as radar means, laser means or camera means or optical sensor means. In addition, accident events can be detected and calculated prior to the occurrence of an accident, with the aid of speed measurements of the vehicle itself and the angle and speed of impact of other traffic participants. Alternatively or additionally, more detailed calculation and prediction of the impact of an accident event can be achieved by means of vehicle data of the traffic participants available in the digital network traffic system. Thus, the pressure reservoir may be vented by activating an electronic venting device before an actual accident occurs. Safety can be advantageously increased by reducing the pressure early before the collision. This can be achieved by relatively space-saving and cost-effective additional measures, preferably without mechanical reinforcement of the vehicle body and the pressure tank and without the need for the installation of further fire-resistant materials.

Drawings

The technology disclosed herein is now explained with reference to the drawings. The attached drawings are as follows:

FIG. 1 is a schematic illustration of a pressure vessel system as disclosed herein; and

fig. 2 is a schematic illustration of a flow chart of the technology disclosed herein.

Detailed Description

Fig. 1 shows a pressure vessel system which is connected to a fuel cell system of a motor vehicle. The pressure vessel 100 may be, for example, a high-pressure gas vessel in which hydrogen is stored. The anode inflow path 215 connects the pressure vessel 100 and the anode a of the fuel cell stack 300. The anode inflow path 215 here includes the pressure reducer 212 and the ejector 234. In the fuel cell stack 300, an electrochemical reaction occurs between the fuel and the oxidant O2 of the cathode sub-system. After the electrochemical reaction, the anode exhaust gas is at least partially recirculated there by the recirculation conveyor 236. Water is deposited in water separator 232 and is discharged through anode purge valve 238 into anode purge line 239. The cathode subsystem here includes an oxidant transporter 410 that compresses the oxidant, which is then cooled in a charge air cooler 420. The cathode K of the fuel cell stack 300 can be shut off here by means of a cathode-side stack shut-off valve 430, 440. Furthermore, a cathode-side bypass 460 is provided here, which branches off upstream of the shut-off valve 430 and opens downstream of the shut-off valve 440.

Furthermore, a pressure relief device 213 is schematically shown here. The pressure relief device 213 is here arranged in fluid parallel to the tank shut-off valve 211. In other words, the tank cut valve 211 and the pressure relief device 213 are not connected in series. The inflow line to the pressure relief device 213 opens directly into the pressure vessel 100. The inflow line may also branch off upstream of the tank shut-off valve 211.

Fig. 2 schematically illustrates a method disclosed herein. The method starts in step S100. In step S2100 it is checked whether a pre-crash situation exists. If a pre-crash condition is not detected, the process begins again at step S100. If a pre-crash situation is detected, the process continues with optional step S300. In step S300 it is evaluated whether the predicted collision is related to a structural failure of a component of the at least one pressure vessel. For example, it may be evaluated for this whether a burst event is likely to occur. If the predicted collision is not associated with a structural failure of a component of the at least one pressure vessel, no pressure relief is performed in step S500. It is then preferably possible in step S550 to close at least the tank shut-off valve 211 and, if necessary, also the other valves of the anode subsystem. If instead in step S300 it is determined that the predicted impact is related to a structural failure of a component of the at least one pressure vessel, the pressure relief is initiated, for example by activating the pressure relief device 213. For this purpose, for example, the control device can send a control signal to the pressure relief device 213 in the form of a valve, which is then opened. In this case, it can also be provided that in step S4150 at least the tank shut-off valve 211 and, if appropriate, also the other valves of the anode sub-system are closed.

The term "at least one" is omitted in part for reasons of readability. If features of the technology disclosed herein are described in singular or indefinite form (e.g. the/a pressure vessel, the/a pressure relief device, the/a controller, the/a valve, etc.), then the plural (e.g. the at least one pressure vessel, the at least one pressure relief device, the at least one controller, the at least one valve, etc.) shall also be disclosed together.

The foregoing description of the invention is for the purpose of illustration only and is not intended to be limiting of the invention. Various modifications and alterations can be made within the scope of the present invention without departing from the scope of the invention and its equivalents.

Claims

1. Method for venting at least one pressure vessel (100) of a motor vehicle, comprising the following steps:

-detecting a pre-crash condition; and is

-taking protective measures for the pressure vessel (100) if a pre-crash situation is detected.

2. The method of claim 1, wherein the taking protective action comprises the steps of: venting the at least one pressure vessel (100).

3. The method according to claim 1 or 2, wherein the detecting comprises the steps of: a value indicative of a degree of damage to the motor vehicle and/or the pressure vessel (100) caused by the collision is determined.

4. The method of claim 3, wherein the at least one pressure vessel (100) is vented if the determined value indicates damage related to a structural failure of a component of the at least one pressure vessel (100).

5. The method according to claim 3 or 4, wherein the at least one pressure vessel (100) is not vented in the event of a pre-crash if the determined value indicates damage unrelated to a structural failure of a component of the at least one pressure vessel (100).

6. The method of claim 5, further comprising the steps of: if a pre-crash condition is detected, the tank shut-off valve (211) is closed.

7. Method according to any of the preceding claims, wherein the pressure relief is performed by activating a pressure relief device (213).

8. The method according to claim 7, wherein the pressure relief device (213) is an overpressure valve or a thermally activatable pressure relief device, and the pressure relief device (213) is electrically openable.

9. Pressure vessel system of a motor vehicle, comprising at least one controller, wherein the controller is configured for performing at least one of the methods disclosed herein.

10. The pressure vessel system of claim 9, further comprising at least one pressure relief valve (213) that initiates pressure relief based on a signal from the controller.