GB2387584A

GB2387584A - Vehicle dc power supply fuel cell

Info

Publication number: GB2387584A
Application number: GB0308423A
Authority: GB
Inventors: Klaus Voggel
Original assignee: Hymer AG
Current assignee: Hymer AG
Priority date: 2002-04-12
Filing date: 2003-04-11
Publication date: 2003-10-22
Also published as: GB0308423D0; DE20205813U1; FR2839289A3; FR2839289B3

Abstract

A recreational vehicle such as a motorhome, caravan, aircraft or marine craft comprises an on-board current supply electrical network 12, and a fuel cell 5 in a direct current branch 13 of the network 12. The direct current branch 13 may be connected to a current supply network for a vehicle drive unit 8 via a cut-off switch 11, and may also supply an alternating current branch 14 via an inverter 15. The electrical capacity of the fuel cell 5 preferably exceeds that of a battery (4 see fig 1), which is preferably wired in parallel with the fuel cell 5. The fuel cell 5 enables the duration of autonomous operation to exceed that of the battery (4). It may also act in combination with the battery 4 to maintain a constant supply as the battery (4) partially discharges. Alternatively, a battery may not be present. The fuel cell 5 may be connected to an exchangeable fuel tank (6 see fig 1), both being positioned under the vehicle floor. Waste heat from the fuel cell 5 may be used in a duct (18 see fig 1) of an air heating arrangement. Waste gases are expelled via a hose (17 see figure 1).

Description

Vehicle with outboard current supply incorporating a fuel cell The subject

of the invention is Vehicle with an on-board current supply by a fuel cell.

The invention is applicable in particular to all types of recreational vehicles, i.e. all land, water and air vehicles and moreover, in particular also motorhomes and caravans.

In recreational vehicles of this type a battery is generally used as the energy source lbr the cunent suppler of the loads connected to the vehicle network.

In the case of a motorhome the battery is charged when the drive unit (consisting. for example of the engine, dynamo, starter and battery) arranged in the base vehicle is in operation and the cut-out switch is therefore connected to the downstream vehicle networic. In the case of caravans there is no Corresponding base vehicle so the vehicle network it supplied win current by connection to the conventional household network. To simplify the description the following will only be based on a rac> torhome, of which

the vehicle network is divWed into a direct current and an alternating current branch.

Corresponding loads are arranged in both branches. In the context, the construction of an vehicle network of this type can be transferred to any other abovenentioned land, water and air vehicles, so merely because of the simpler description only a

motorhome is described hereinafter. However, the invention refers to all the above mentioned vehicles.

In a vehicle according to Me invention direct, alternating or three phase currents may be available in the vehicle network. There are the voltage ranges 12 volt, 24 volt, 42 volt, 230 volt and 380 volt.

The corresponding adaptation takes place via a voltage transformer which is optionally coupled to rectifiers or inverters.

In vehicles of this type there was previously the disadvantage that during decoupling from the base vehicle it was necessary to fall back directly to the battery in the vehicle network if the vehicle was not connected to a household network.

The capacity of the battery was exhausted straightaway and this soon had to be reloaded according to the number and the consumption of the connected loads.

The object is therefore to further improve the on-board current supply of recreational vehicles of the type mentioned at the outset in such a way that when there is no connection to the public network or in the event of interruption to the current supply of the base vehicle a longer duration of use of the vehicle network is provided.

To solve the problem posed, the invention is characterized in that a fuel cell is arranged in the direct current branch of the vehicle network.

It can be provided in the first embodiment of the invention that the fuel cell is arranged parallel to the battery arranged in the direct current branch.

In a second embodiment of the invention it is provided that the fuel cell is arranged in the direct current branch as the only current supplier and the battery of the vehicle network is dispensed with.

In the third embodiment of the invention it can be provided that a plurality of fuel cells are arranged in serial or parallel connection in the direct current branch of the vehicle network _... _. _.. _. _.. A.

With the given technical teaching the substantial advantage is now produced that! because of the greater electrical capacity of the fuel cell the vehicle network can be operated for a longer period than in comparison with the battery in autonomous operation, without reloading or connection to the public network being necessary.

Particular advantages are produced when the fuel cell is used in parallel connection to the already available battery in the vehicle network. It is known that the capacity of the battery decreases after correspondingly long autonomous operation and therefore the current at the current loads also reduces. The fuel cell connected in parallel to the battery compensates this and said loads can be supplied with constant voltage and, constant current over a long period. The parallel connection of the battery and fuel cell also has particular advantages.

A so-called PEM fuel cell is preferred as the cell type for a fuel cell (PEMFC).

This is a proton exchange diaphragm fuel cell which uses a polymeric diaphragm as the electrolyte. Methanol is preferably used as the anode gas, so a use range of O to 80 C is produced.

The power can be up to 250 kW, wherein according to the present invention a relatively small fuel cell with a power of about 1.2 KwH/day is used.

A fuel cell of this type thus has a power of about 50 W and with a 12 V direct current supplies a current of about 4.1 A. The relatively low current is enough to keep the battery stable over a long period in parallel connection to the battery and in particular to prevent exhaustive discharge.

The efficiency with the use of methanol is 40%.

It is preferred if the fuel cell is directly coupled to a corresponding methanol tank, this methanol tank being exchangeably flanged onto the fuel cell.

A tank with a content of 2.5 litres is flanged onto the fuel cell, exchangeable tanks being included entirely in the underfloor region of the vehicle, the tanks then being exchangeable with each other if necessary.

A particular advantage is produced in the invention in that the waste heat emitted by the fuel cell can be used for the interior heating of the vehicle.

For this purpose, the invention provides that the fuel cell is arranged in the region of a hot air duct in the underfloor region of a vehicle and that the waste heat provided by the fuel cell is fed into the air heating of the vehicle.

A further advantage of the invention is that the previously mentioned and already generally available battery in the vehicle network of the vehicle can be dispensed with and instead the battery of the drive unit can also be used. In this case, the fuel cell therefore serves to supply the entire direct current circuit of the vehicle.

However, as is known, peak currents occur in this direct current circuit when, for example, an air conditioning apparatus, a refrigerator or a TV system is connected.

Peak currents of this type are compensated by the battery of the drive unit. In this case, a constant current connection is available to the direct current circuit of the drive unit and the direct current circuit of the vehicle network. The fuel cell is connected in parallel to the battery of the drive unit, before this event. The battery of the vehicle network is then dispensed with.

In this combination there is the further advantage that the battery of the drive unit is protected against exhaustive discharge. There is always a back-up supply or a charging current which is supplied from the fuel cell and which, in the event of an exhausted vehicle battery, reloads the battery.

In this way, the fuel cell according to the invention is supplemented in the direct current branch of the vehicle network by the battery of the drive unit.

The subject of the present invention emerges not only from the subject of the individual claims, but also from the combination of the individual claims with one another.

All the details and features disclosed in the documents, including the abstract, in particular the spatial design shown in the drawings, are claimed as essential to the invention, in as much as they are novel, individually or in combination, compared to the prior art.

The invention will be described in more detail hereinafter with the aid of the drawings showing only one embodiment.

In the process, further substantial features and advantages of the invention emerge from the drawings and their description.

In the drawings: Fig. 1 shows a schematic view of a motorhome according to the invention partly in a cut-open state, Fig. 2 shows a schematic view of the current network of the motorhome according to Fig. 1.

Fig. 1 shows in general a land vehicle 1 in the form of a motorhome, of which the base region 2 is partially cut open for a better overview. In this base region 2 is formed a receiving space, in which at least one fuel cell 5 provided in the spatial vicinity of a conventional battery 4, is arranged. It is important here that the two units 4, 5 are arranged in the base region 2 and this base unit 2 is constructionally separated from the passenger cell 3.

The fuel cell 5 is releasably connected to an exchangeable tank 6, the connection between the fuel cell and the tank being produced via a fuel line 7.

At another point of the base region 2 more tanks 6 can be included which are then exchanged for the empty tank 6. Provided on the fuel cell 5 is also a waste gas hose 17 which leads to the outside and via which the waste gases are removed to the outside.

For better use of the waste heat from the fuel cell 5, it is provided that the fuel cell 5 is located in a hot-air duct 18 of the air heating of the land vehicle 1, so that for example the heating air is guided in the arrow direction 16 via the fuel cell 5 and the air thus heated is guided into the vehicle.

Fig. 2 shows in general that the drive unit 8 is provided with a current supply network which is designed separately from the vehicle network 12 of the motorhome. The connection of the two current networks takes place via a cut-off switch 11.

The drive unit 8 comprises in known manner an engine 10 which is intended for the drive of the vehicle, a battery 9 pertaining thereto, a dynamo and other units.

The vehicle network 12 of the motorhome is divided into a direct current branch 13 and an alternating current branch 14.

According to the invention at least one fuel cell 5 is arranged in the direct current branch 13.

Also arranged in the direct current branch is the conventional vehicle battery 4 and a series of loads, such as for example, air conditioning, a refrigerator, a TV system and lamps and the like. It is also known than an inverter 15 is arranged in the alternating current branch, the inverter 15 generating a corresponding alternating current from the direct current, the alternating current in turn supplying a series of farther ''nits _...._. _...._.

An advantage of the described arrangement is that the battery 4 can also optionally be dispensed with and in this embodiment the cut-off switch 11 remains constantly closed. The fuel cell 5 is thus connected in parallel to the vehicle battery 9 and charges it in the event of exhaustive discharge. In the embodiment shown, however, the fuel cell 5 is connected in parallel to the battery 4 and the cut-off switch 11 is closed as soon as the engine 10 is running and the dynamo supplies current, so this current is fed from the drive unit into the vehicle network 12.

On the other hand, if the engine 10 is switched off, the cut-off switch 11 is opened and the vehicle network 12 operates in autonomous operation, the fuel cell 5 then supporting the battery 4.

For reasons relating to the drawings, the connection to a conventional household network with 220 or 380 volt is not shown.

List of reference numerals 1 land vehicle 2 base region 3 passenger cell 4 battery 5 fuel cell 6 tank 7 fuel line 8 drive unit 9 battery 1 0 engine 11 cut-off switch 12 vehicle network 13 direct current circuit 14 alternating current branch 1 5 inverter 16 arrow direction 17 waste gas hose 18 hot-air duct

Claims

1. Recreational vehicle with an on-board current supply, characterized in that a fuel cell (5) is arranged in the direct current branch of the vehicle network (12).

2. Recreational vehicle according to claim 1, characterlsed in that the electrical capacity of the fuel cell (5), is such that the vehicle neharork (12) can be operated over a longer period than it can be operated in comparison with a battery (4) in autonomous operation, without it needing recharging or a connection to the public network.

3. Recreational vehicle according to claim 1 or 2, characterized in that the fuel cell (5) is arranged parallel to the battery (4) arranged in the direct current branch (12).

4. Recreational vehicle according to claim 1, 2 or 3, characterized in that a plurality of fuel cells (5) are arranged in serial or parallel connection in the direct current branch of the vehicle network (12).

5. Recreational vehicle according to claim 1 or 2, characterized in that the fuel cell (5) is arranged as the only current supplier in the direct current branch (12) and a battery (5) for the vehicle network (12) is dispensed with.

6. Recreational vehicle according to any one of claims 1 to 5, characterized in that the drop in voltage in the direct current branch (13), caused by a decrease in the capacity of the battery (4) after correspondingly long, autonomous operation is compensated by the fuel cell (5) connected in parallel to the battery (4) and the loads can be supplied over a long time period with constant voltage and constant current.

7. Recreational vehicle according to any one of claims 1 to 6, characterized in that the fuel cell (5) serves to supply the entire direct current circuit (13) of the vehicle (1).

8. Recreational vehicle according to any one of claims 1 to 7, characterised in that the battery of the drive unit (8) is protected against exhaustive discharge in that a back-up supply or a charging current is always produced which is supplied by the fuel cell (5) and which recharges the vehicle battery (4) when it is exhausted.

9. Recreational vehicle according to any one of claims 1 to 8, characterised in that the battery (4) and the fuel cell (5) are arranged in the base region (2) of the vehicle (1) and the base region (2) is constructionally separated from the passenger cell (3).

10. Recreational vehicle according to any one of claims 1 to 9, characterised in that a tank (6) is flanged on to the fuel cell (5).

11. Recreational vehicle according to any one of claims 1 to 10, characterised in that the fuel cell (5) is detachably connected to the exchangeable tank (6), the connection being between the fuel cell (5) and the tank (6) via a fuel line (7).

12. Recreational vehicle according to any one of claims 1 to 11, characterised in that a plurality of exchangeable tanks (6) are included in the under-floor region of the vehicle (1) which can be exchanged with one another if necessary.

13. Recreational vehicle according to any one of claims 1 to 12, characterised in that the waste heat emitted by the fuel cell (5) is used for the interior heating of the vehicle (1).

14. Recreational vehicle according to any one of claims 1 to 13' characterised in that the fuel cell (5) is arranged in the region of a hot-air duct (18) in the under-floor region of a vehicle (1) and in that the waste heat provided by the fuel cell (5) is fed into the air heating of the vehicle (1).

_..

15. Recreational vehicle according to any one of claims 1 to 14, characterised in that a so-called PEM fuel cell is used as the cell type for a fuel cell (5).

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16. Recreational vehicle according to any one of claims 1 to 15, characterized in that a so-called PEMFC fuel cell is used as the cell type for a fuel cell (5).