DE10244139A1 - Safety system for a test installation for a hydrogen converting device, especially a hydrogen engine test bed, has means for comparing hydrogen delivery with hydrogen consumption - Google Patents

Abstract

Safety system for a test installation for a hydrogen converting device (2). Accordingly a transport device or pump (12) is controlled by a controller (13) so that its hydrogen throughput is matched to the consumption of the hydrogen converter. The controller also compares a hydrogen transport parameter determined between the transport device and the converter with a parameter synchronized with the hydrogen consumption. If a difference threshold is exceeded, hydrogen supply is immediately switched off.

Description

The invention relates to a Security system for the operation of hydrogen-converting devices in closed or partially closed rooms or containers.

Operation of hydrogen conversion devices such as internal combustion engines is in closed or partially closed rooms associated with special security risks arising from the properties gaseous hydrogen result. So hydrogen shows compared to gasoline and diesel fuels a significantly larger ignitable concentration range Air that ranges from 4% to 80%. In addition, the ignition energy is required significantly smaller, which means that the explosion threshold is reached earlier becomes.

This has the consequence that for the operation of hydrogen-converting devices on test benches or for driving and / or parking of motor vehicles with hydrogen engines in garages and the like Facilities need special security measures to be taken in the event of a malfunction a sudden Rise in the hydrogen concentration in the area of hydrogen-converting To prevent device or the hydrogen engine.

Conventional hydrogen engine test benches next to a hydrogen conveyor the usual, also on test benches for petrol and Diesel engines installed ventilation system on without however, the special requirements of operating with hydrogen to consider. The ventilation is there for dimensioned such a continuous volume flow of air, in which it is still possible for the operating personnel is the test cell of the test bed to enter.

Hydrogen sensors are used as a safety device in the test cell as well as shut-off valves in the hydrogen supply to the test cell, which is an impermissible Hydrogen concentration (> 4%) in the test cell detect and if exceeded a predetermined limit value the hydrogen supply into the cell interrupt. So that is conventional Test benches one to achieve a minimum total reaction time of 1 s within which the Security system responds and the hydrogen supply is interrupted.

A large number must be used to ensure safe operation of hydrogen sensors are used to creep or suddenly Component leaks that occur must be detected in good time because in the event of a malfunction of a test item hydrogen unpredictable in the test cell can distribute. With a high hydrogen conversion of the test object about that addition the problem that it too to an ignitable hydrogen concentration within the reaction time of 1 s in the test cell can come.

The volume of the test cell in Connection with the above-mentioned safety device limited thus the maximum hydrogen conversion within the test cell. This in turn places a performance limit on the devices to be examined, motors in particular. With the conventional test bench dimensions can thus only examine motors up to an output of around 37 kilowatts. It is immediately apparent that for the investigation in one performance range ten times larger either test cells provided with a considerably larger volume Need to become or the throughput of the ventilation infrastructure in a corresponding manner Dimensions increased would have to be the above-mentioned reaction times even with a high hydrogen throughput to be able to comply. However, this is associated with a high level of structural complexity.

The invention is based on the object here To remedy the situation. An object of the invention is therefore a security system for the Operation of hydrogen conversion devices in closed or partially closed rooms or containers to indicate that on the one hand allows a high hydrogen throughput, on the other hand, however, avoids the structural effort mentioned above.

This task is done through a security system solved of the type mentioned at the beginning, which includes: a metering device with a hydrogen inlet for connection with an outside of the room or container located hydrogen supply and a hydrogen outlet for connection with the hydrogen-converting device, and with a hydrogen delivery device, the one with the inlet and connected to the outlet is and by means of a control device consumption-synchronized with the hydrogen-converting device is operated, wherein in the Control device is compared with a hydrogen supply parameter, between the hydrogen conveyor and the hydrogen conversion device is measured, and in the one upon detection of a deviation from a corresponding one consumption-synchronous value by more than a predetermined tolerance an error signal is generated.

The dosing device ensures that always only exactly that amount of hydrogen gets into the room or container, actually to be implemented, i.e. the hydrogen delivery rate in the room or container is always synchronized in time and quantity to the hydrogen consumption of the implementing device set or regulated. Does the fall Hydrogen supply parameters from a certain tolerance range out, this is called a disturbance interpreted, whereupon appropriate countermeasures can be taken, for example by switching off the hydrogen supply immediately.

Since the measurement takes place against a very small volume of space, namely the volume of space in the conveyor tract between the hydrogen conveyor tion and the hydrogen-converting device, deviations become noticeable very quickly. For example, if a leak occurs in the test cell, the pressure in the conveyor tract quickly drops below its minimum. If, on the other hand, the amount of hydrogen supplied in the room or container is not completely removed because, for example, there is a defect in the consumer, the pressure in the conveyor tract very quickly rises above its maximum.

Defects in the dosing device themselves are on similar Detectable in this way and can be checked by suitable plausibility checks Defects in the room or container distinguish so that at subordinate safety relevance not always a shutdown the hydrogen must be supplied to the room or container, but also milder reactions or just error messages are triggered can.

This way it becomes a safer one Operation of hydrogen conversion devices in closed or partially closed rooms or containers guaranteed with unlimited hydrogen mass flow.

The security system can, for example, in a test room or a test cell be installed, in which or in which the hydrogen-converting device, in particular a hydrogen-powered internal combustion engine is housed. This means that hydrogen test benches are very spacious compact configuration. In particular, it is already possible existing test rooms and test cells to equip with the security system to thereby providing a hydrogen engine test bench for high engine outputs, without this the ventilation infrastructure or the spatial Dimensions of the test room or the test cell changed should be.

The metering device is preferably used into the wall of the test room or the test cell integrated.

It is also possible that security system according to the invention to combine with a hydrogen-powered internal combustion engine. Here, the metering device is preferably in the hydrogen fuel supply system integrated into the hydrogen-powered internal combustion engine.

A particularly advantageous option consists of the dosing device in a safety jacket a liquid hydrogen tank install. In this way the hazard potential can be reduced accordingly equipped Motor vehicles with a view to driving into garages and the like be significantly reduced.

According to an advantageous embodiment of the invention is the hydrogen conveyor a pressure chamber downstream, in which at least one sensor for Detection of a hydrogen supply parameter, in particular the pressure and / or mass flow and / or volume flow. About the pressure chamber pressure fluctuations can be compensated so that the hydrogen-converting Device with approximately hydrogen constant pressure available can be posed or the risk of a test falsification reduced due to pressure fluctuations of the hydrogen delivery device becomes.

In another advantageous one The hydrogen delivery device has an embodiment hydrogen feed device upstream of the pressure chamber, that of the hydrogen feeder of the hydrogen converting Device is simulated. This makes it easier to carry out a consumption synchronous operation between the dosing device and the hydrogen-converting device considerably. The components on the part of the dosing device can be achieved through appropriate series components of the hydrogen-converting device. With regard a higher one Accuracy, however, identical components are preferably used, the additional are calibrated.

For a particularly simple mode of operation for the investigation of internal combustion engines and similar Devices can the hydrogen feed device on the side the metering device may be provided with inlet valves which open into the pressure chamber. These intake valves are about the control device with the control signals of the hydrogen feed device the hydrogen-converting device. In this way consumption-synchronous operation with little control effort realize.

In addition, in the control device a correction of the control signals for the intake valves to the effect that a change the blowing times the pressure in the pressure chamber is evened out. This eliminates pressure fluctuations, from an intermittent operation of the intake valves result, reduced. The hydrogen conversion device can do the necessary Amount of hydrogen provided with a more uniform pressure level become.

According to another advantageous Embodiment of the invention has the hydrogen delivery device a pump and / or a pressure regulator on the pressure chamber and an optional hydrogen feed device are upstream.

To detect any leaks in the Dosing device itself can be in an advantageous embodiment casing be filled with an inert gas, for example helium or nitrogen, that surrounds the other components of the dosing system. Is in the housing a hydrogen sensor arranged when a certain Hydrogen content responds and generates a fault signal.

The invention now follows explained in more detail with reference to exemplary embodiments shown in the drawing. The Drawing shows in:

1 is a schematic representation of a first embodiment of a security system according to the invention in a simple embodiment, and in

2 is a schematic representation of a second embodiment of a safety system for a test bench for water internal combustion engines.

The first embodiment in 1 shows a security system 1 for the operation of a hydrogen-converting device 2 , here an example of an internal combustion engine in a closed space 3 , which is part of an engine test bench. The space 3 has a ventilation system 4 and 5 that communicates with the ambient air. Outside the room 3 there is still a hydrogen supply 6 in the form of a tank for supplying the hydrogen-converting device 2 , The emissions of the device 2 are via a disposal line 7 out of the room 3 dissipated.

How 1 can be seen is between the hydrogen supply 6 and the hydrogen converting device 2 a dosing device 8th of the security system 1 arranged which is the total hydrogen supply in the room 3 controlled.

The dosing device 8th has a gas-tight housing 9 , in which the further components of the metering device are arranged, which lead hydrogen through the housing 9 enable. To do this, the housing points 9 a hydrogen inlet 10 for connection to the hydrogen supply 6 and a hydrogen outlet 11 for connection to the hydrogen-converting device 2 on.

Between hydrogen inlet 10 and hydrogen outlet 11 is in the housing 9 a hydrogen conveyor 12 coupled in by means of a control device 13 consumption-synchronized with the hydrogen-converting device 2 is operated. For this purpose, the desired consumption curves of the device 2 the control device 13 made available. The latter is located inside the housing 9 , suitable interfaces and electrical feedthroughs are provided on this. The consumption profiles can be made available, for example, via a computer program. However, it is also possible to obtain the corresponding information directly from the control system of the hydrogen conversion device 2 tap and, if necessary, modified to the control device 13 the dosing device 8th transferred to.

A sensor is used to regulate the hydrogen supply 14 a hydrogen supply parameter between the hydrogen conveyor 12 and the hydrogen converting device 2 , ie recorded on the pressure side in the conveyor wing. This parameter is in the control device 13 adjusted continuously or at high frequency with a corresponding consumption-synchronous value. This is preferably done via pressure. However, other parameters, such as, for example, a volume flow or mass flow, can be used for evaluation either alone or in combination with one another. This allows the hydrogen supply to be quickly adapted to the required hydrogen requirement. This has the advantage that there is always only as much hydrogen in the room 3 is promoted, as there by the device 2 to be implemented.

If it is ascertained during the comparison that the detected value deviates from the corresponding consumption-synchronous value by more than a predetermined tolerance within a certain time interval, a fault signal is generated. The interruption of the hydrogen supply can then be triggered with the fault signal, for example simply by the pump 15 the hydrogen conveyor 12 is switched off. It is also possible to arrange an additional shut-off valve which hermetically seals the hydrogen supply line when actuated accordingly.

Because the conveyor wing compared to the room 3 has only a very small volume, discrepancies between the amount of hydrogen to be supplied and the amount of hydrogen actually used lead to a quickly noticeable change in pressure. Occurs, for example, on the hydrogen-converting device 2 If there is a leak, the pressure in the conveyor tract quickly drops below its current target minimum. On the other hand, the amount of hydrogen supplied by the device 2 If it is not used up in the intended manner, for example because there is a fault or a defect in it, the pressure in the conveyor tract rises very quickly above its current target maximum.

This is from the security system 1 recognized immediately and regardless of the hydrogen throughput, so that in time before reaching a critical hydrogen concentration in the room 3 can be switched off. Also malfunctions in the dosing device 8th can be recognized in a similar way. Suitable plausibility checks enable a distinction to be made between faults in the hydrogen-consuming device 2 , In this way, in cases of minor safety relevance, the hydrogen supply in the room does not always have to be switched off 3 respectively. Rather, less restrictive measures, such as throttling the supply, or even triggering error messages, can also be triggered.

For detecting leaks in components of the dosing device 8th inside the case 9 serves a hydrogen arranged in this sensor 16 which responds when a certain hydrogen content is determined and generates an error signal. This fault signal can also be in the control device 13 processed and used to switch off the hydrogen supply. In terms of high measurement quality, the housing is 9 also filled with an inert gas that surrounds the other components of the dosing system.

In principle, the metering device 8th anywhere inside or outside the room 3 be arranged as long as for gas-tight connecting lines to the hydrogen supply 6 or the hydrogen-converting device 2 is taken care of. In the embodiment shown here, the dosing device 8th however in the wall of the test room 3 installed, so that the connection to the hydrogen supply 6 with secured.

In a modification of the exemplary embodiment explained above, the metering device can 8th can also be integrated into the hydrogen fuel supply system of a hydrogen-powered internal combustion engine, which is then preferably installed in a safety jacket of a liquid hydrogen tank.

The second embodiment in 2 refers to a security system 1 for a test cell which corresponds to the first exemplary embodiment in terms of use and use, but differs from the latter in relation to the metering device.

The dosing device 8th' of the second embodiment shows in addition to the hydrogen delivery device 12 ' in the housing 9 additionally a downstream pressure chamber 20 on in which the sensor 14 for detecting a hydrogen supply parameter, preferably the pressure. As an alternative or in addition, the mass flow and / or volume flow of the hydrogen supplied can also be recorded here.

The hydrogen conveyor 12 ' includes next to a pump 15 and / or a pressure regulator additionally a hydrogen feed device upstream of the pressure chamber 21 that of the hydrogen feed device 22 the hydrogen-converting device 2 is reproduced. The hydrogen feeder 21 has inlet valves 23 on that in the pressure chamber 20 flow out and over the control device 13 with the control signals of the hydrogen feed device 22 the hydrogen-converting device 2 be supplied.

In the room 3 or the test cell, the hydrogen only passes through the metering device 8th' , which essentially consists of: the pump, which in the simplest case is identical in construction with the corresponding series component 15 and / or a pressure regulator, which in the simplest case is identical in construction to the corresponding series component, but here calibrated control device 13 , in the simplest case with the corresponding series components of identical construction, but here calibrated injection valves 23 , the pressure or injection chamber 20 with the calibrated pressure sensor 14 as well as with the corresponding series components of identical injection valve output stages 24 ,

The dosing device 8th' is in a gas-tight housing 9 with also gastight electrical feedthroughs and hydrogen feedthroughs installed, which includes the hydrogen supply connection in the test cell wall. The housing 9 can also be filled with an inert gas such as helium or nitrogen and a hydrogen sensor 16 be equipped, the eventual, u. U. harmless leakage of the dosing device 8th' itself detected and sent to the control device 13 reports.

The mode of operation of the second exemplary embodiment will now be briefly explained below. In operation, the hydrogen comes out of the room 3 or the test cell supplying connection not via a direct line into the fuel supply system of the internal combustion engine (hydrogen converting device 2 ), but first in the dosing device explained above 8th' , This basically works identically to the engine fuel supply, ie the inflowing hydrogen is pumped 15 and a pressure regulator compressed to the original rail pressure on the engine and the injection valves 23 fed. The control device 13 the original control signals of the engine injection valves, the number of which corresponds, for example, to the number of cylinders in the engine, are supplied. The control device 13 generated from this, taking into account further measurement and monitoring variables such as B. the injection chamber pressure, the input signals for the injection valve output stages 24 which in turn are the injection valves 23 drive.

The number and quantity of the injection valves, which are controlled in synchronism with the injection valves of the engine, are synchronized 23 blow hydrogen into the pressure or injection chamber 20 , from where it is fed via a line to the fuel supply system of the engine. The injection chamber pressure is measured using the pressure sensor 14 detected and in a control loop by correcting the injection times constant on z. B. regulated 1.5 bar. The injection time correction quantity is limited to a value which is just sufficient to compensate for tolerances between the injection valve instances of the engine.

An assumed malfunction of the hydrogen-carrying system in the room 3 or the dosing device described here 8th' with safety-critical effect has a deviation between that of the dosing device 8th' offered and that in the room 3 flowing hydrogen result, whereby the monitored injection chamber pressure immediately leaves its tolerance range. For example, if there is a leak in the room, it drops 3 or the test cell of the blowing chamber pressure below its minimum. This causes the injection valves to switch off immediately 23 in the dosing device 8th' and thus prevents the explained hydrogen supply into the room 3 or the test cell. Will the amount of hydrogen delivered in the room 3 or not completely removed in the test cell, for example because of a malfunction or a defect in the hydrogen-converting device 2 or the engine is present, the injection chamber pressure rises above its maximum and, although less critical to safety, causes the hydrogen supply to be switched off.

The volume of the pressure or injection chamber 20 including the lines to and on the engine can be very small, e.g. B. 2 1. Since the reaction time of the injection chamber pressure measuring point to a pressure drop due to a fault is below the tolerated value in the ms range, ie by about two orders of magnitude smaller than the test cell hydrogen sensor system, the space is limited in the event of a fault 3 or the test cell introduced amount of hydrogen on the blowing chamber content. With a hydrogen mol mass of 2 g and a molar volume of 22.4 l (under normal pressure and at room temperature), taking into account the gas equation px V = const. in the pressure or blowing chamber 20 with an assumed volume of 2 l and an assumed pressure of 1.5 bar, about 0.13 g of hydrogen is present, which is again about an order of magnitude below the generally applicable limit value.

The mode of operation shown here guaranteed an operation protected against the escape of hydrogen Hydrogen internal combustion engines any power in a hydrogen dosing synchronized with this consumption equipped test cell. A surveillance the hydrogen concentration in the test cell remains as an additional one Security level still makes sense, but comes with the delay in response today available sensors without the Mass flow of hydrogen into the test cell should be limited.

The application of the security concepts described does not stay on the stationary Hydrogen engine test limited. For example, the integration of a consumption-synchronous system is also conceivable Dosing device in the hydrogen fuel supply system of each automobile powered by a hydrogen engine to its operational security in closed or partially closed clear such as. Underground garages and tunnels, or to ensure at all an operating license that includes these areas obtain.

The system can be used in motor vehicles as a consumption-synchronous dosing pump within the safety jacket a liquid hydrogen tank be arranged so that this already protected area only that amount of hydrogen can leave, which is processed by the engine. Because in the motor vehicle also other aspects of operational safety, in particular the Engine power availability in traffic a suitable sensor system is recommended for the detection of areas critical to hydrogen safety, this is the safety function of the in-vehicle metering device activated or deactivated again.

Claims (11)

Safety system for the operation of hydrogen-converting devices ( 2 ) in closed or partially closed rooms ( 3 ) or containers, comprising a dosing device ( 8th . 8th' ) with a hydrogen inlet ( 10 ) to connect to an outside of the room ( 3 ) or container of hydrogen ( 6 ) and a hydrogen outlet ( 11 ) for connection to the hydrogen-converting device ( 2 ), and with a hydrogen conveyor ( 12 . 12 ' ) with the inlet ( 10 ) and the outlet ( 11 ) is connected and by means of a control device ( 13 ) consumption-synchronized with the hydrogen-converting device ( 2 ) is operated, with the control device ( 13 ) a comparison is made with a hydrogen supply parameter which is between the hydrogen delivery device ( 12 . 12 ' ) and the hydrogen conversion device ( 2 ) is measured, and in which a fault signal is generated if a deviation from a corresponding consumption-synchronous value is determined by more than a predetermined tolerance. Security system according to claim 1, characterized in that the hydrogen delivery device ( 12 ' ) a pressure chamber ( 20 ) is connected downstream, in which a sensor ( 14 ) for detecting a hydrogen supply parameter, in particular the pressure and / or mass flow and / or volume flow. Security system according to claim 1 or 2, characterized in that the hydrogen delivery device ( 12 ' ) one of the pressure chamber ( 20 ) upstream hydrogen feed device ( 21 ) which the hydrogen feed device ( 22 ) the hydrogen conversion device ( 2 ) is reproduced. Security system according to claim 3, characterized in that the hydrogen feed device ( 21 ) Inlet valves ( 23 ) which extends into the pressure chamber ( 20 ) and the control device ( 12 ' ) with the control signals of the hydrogen feed device ( 22 ) the hydrogen conversion device ( 2 ) are supplied. Security system according to one of claims 1 to 4, characterized in that in the control device ( 12 ' ) a correction of the control signals for the inlet valves takes place in such a way that a change in the injection times of the pressure in the pressure chamber ( 20 ) is evened out. Security system according to one of Claims 1 to 5, characterized in that the hydrogen delivery device ( 12 . 12 ' ) a pump ( 15 ) and / or a pressure regulator, which the pressure chamber ( 20 ) and a possibly available hydrogen feed device ( 21 ) are connected upstream. Safety system according to one of claims 1 to 6, characterized in that the metering device ( 8th . 8th' ) a housing ( 9 ) that the other components of the metering device ( 8th . 8th' ) surrounds, in which case ( 9 ) a hydrogen sensor ( 16 ) is arranged, which responds when a certain hydrogen content is determined and generates a fault signal. Security system according to claim 7, characterized in that the housing ( 9 ) is filled with an inert gas. Safety system according to one of claims 1 to 8, characterized in that the metering device ( 8th . 8th' ) is integrated into the hydrogen fuel supply system of a hydrogen-powered internal combustion engine. Safety system according to claim 9, characterized in that the metering device ( 8th . 8th' ) is integrated in a safety jacket of a liquid hydrogen tank. Safety system according to one of claims 1 to 8, characterized in that the metering device ( 8th . 8th' ) in the wall of a test room ( 3 ) is installed in which the hydrogen-converting device ( 2 ), in particular a hydrogen-powered internal combustion engine.