Gaseous fuel tank for internal combustion engine

Abstract

The invention relates to a tank assembly for gaseous fuel, in particular for a fuel delivery system of an internal combustion engine, comprising: one or more tanks (12) configured for containing gaseous fuel; and a housing (20) having a plurality of panels (20.i) that define an internal volume (21). The one or more tanks (12) are arranged inside the housing (20), and remaining space is filled with a porous filling material (26, 26.1) having a porosity that is sized to quench an ignition event in the internal volume due to gaseous fuel leakage. Specifically, the porous filling material (26, 26.1) has a porosity with a characteristic diameter that is less than or equal to a quenching distance of the gaseous fuel.

Description

[0001] P-DELPHI-456 / WO 1

[0002] GASEOUS FUEL TANK FOR INTERNAL COMBUSTION ENGINE

[0003] Technical field

[0004] The present invention generally relates to fuel tanks in the context of internal combustion engines, and in particular to fuel tanks for gaseous fuels.

[0005] Background Art

[0006] It is well known within the art of Gaseous fuel tanks, particularly those designed for storing hydrogen (H2), have become increasingly important in the automotive industry as part of the shift towards cleaner energy sources. These tanks are typically classified as Type III or Type IV, depending on their construction.

[0007] Type III tanks consist of a thin metal liner fully wrapped with a composite material shell, while Type IV tanks feature a polymer liner wrapped with a composite material shell. Both types are designed to withstand high pressures, often up to 700 bar, to store sufficient quantities of gaseous fuel for practical vehicle range.

[0008] One of the primary concerns associated with gaseous fuel tanks, especially those containing hydrogen, is the risk of leakage and subsequent explosion. Hydrogen is particularly challenging due to its low ignition energy and wide flammability range. This safety risk is acute with hydrogen, as it can ignite with minimal energy input and form explosive mixtures in a broad range of concentrations.

[0009] To mitigate these risks, fuel tanks for gaseous fuels like hydrogen are typically arranged outside of the vehicle. This placement strategy aims to minimize the potential harm to occupants in case of a leak or explosion. However, this approach leads to significant limitations on the use of the vehicle. For instance, it can create issues with parking in enclosed spaces, such as underground garages or certain parking structures, due to safety regulations and ventilation requirements.

[0010] The external placement of hydrogen tanks also poses challenges for vehicle design and aerodynamics. It can limit the available space for other components and potentially impact the vehicle's overall performance and efficiency.

[0011] Furthermore, the safety considerations extend beyond normal operation to include scenarios such as vehicle collisions and fires. Extensive testing and certificationP-DELPHI-456 / WO 2

[0012] processes have been developed to ensure that these tanks can withstand various extreme conditions without catastrophic failure.

[0013] These safety concerns and design constraints have led to ongoing research and development efforts aimed at improving the safety, efficiency, and practicality of gaseous fuel tanks, particularly for hydrogen-powered vehicles. The industry continues to seek innovative solutions that can address these challenges while enabling wider adoption of hydrogen fuel cell vehicles.

[0014] The invention seeks to provide an improved tank design that reduces explosion risks.

[0015] Technical problem

[0016] The invention seeks to provide an improved tank design that reduces explosion risks.

[0017] General Description of the Invention

[0018] In order to overcome the above-mentioned problem, the present invention relates to a tank assembly for gaseous fuel as claimed in claim 1.

[0019] The tank assembly for gaseous fuel, in particular for a fuel delivery system of an internal combustion engine, comprising:

[0020] - one or more tanks configured for containing gaseous fuel;

[0021] - a housing having a plurality of panels that define an internal volume that accommodates the one or more tanks and associated accessories;

[0022] The unoccupied space inside the internal volume of the housing is essentially completely filled with a porous filling (or porous filler material) material having a porosity that is sized to quench an ignition event in the internal volume due to gaseous fuel leakage.

[0023] The invention provides a tank assembly in which the gas tanks, and related equipment, are embedded in porous filling material having a porosity designed to quench any ignition of gaseous fuel having leaked from the thanks and thereby prevent flame propagation.

[0024] One merit of the invention is to be able to provide a tank assembly within a closed housing surrounding the gas tanks, with full mitigation of the explosive risk even ifP-DELPHI-456 / WO 3

[0025] the leakage is very high. This significantly differs from the conventional approach that relies on passive ventilation to reduce explosive risks.

[0026] In particular, the porous filling material has a porosity with a characteristic diameter that is less than or equal to a quenching distance of the gaseous fuel. Advantageously, the quenching distance may be chosen to cover at least 70%, preferably at least 80 or 90%, of the gas concentration range, ensuring that it effectively addresses ignition over a broad spectrum of fuel gas concentrations In embodiments, the porous filling material has a porosity with an average effective passage diameter that is no greater than 0.50 mm, and e.g. in the range 0.25 to 0.50 mm. This configuration is particularly efficient for applications as hydrogen tanks (gaseous fuel includes 95 w.% or more hydrogen).

[0027] Any appropriate porous filling material may be used. It can be made from a metalbased material, a polymer-based material, or of a composite material. It may be a monolithic material or a combination of materials.

[0028] In embodiments, the porous filling material may consist of a single material type and form a monolithic, continuous volume occupying the unoccupied space.

[0029] In embodiments, the porous filling material may consist of a plurality of porous elements that are shaped to collectively fill the unoccupied space. The porous elements are may be of same or different composition.

[0030] The porous filling material, respectively porous elements, may be selected from the group consisting of a reticulated lattice, a reticulated foam, and an open-cell foam. In embodiments, the porous filling material, respectively porous elements, consists of a polymer foam, in particular a reticulated polyurethane foam. The polymer foam may include a flame retardant.

[0031] In embodiments, a plurality of partition walls made from porous metallic material extend inside the internal volume and divide the latter into a plurality of sub-volumes, said porous metallic material having a porosity similar to said porous filling material, or smaller. For example, a plurality of said partition walls may extend vertically, parallel to one another, between opposite side walls; and / or a plurality of secondP-DELPHI-456 / WO 4

[0032] partition walls may extend horizontally, parallel to one another, between opposite side walls.

[0033] The partition walls may be made from a metal or metallic alloy having good thermal conductivity, in particular selected from copper, copper allow, aluminum or aluminum alloy. This avoids issues due to thermal inertia.

[0034] In embodiments, each gas tank comprises one on-tank valve and at least one thermal pressure relief device, supply piping connecting the on-tank valves and safety piping interconnecting the thermal pressure relief devices.

[0035] In embodiments, least one gas sensor is arranged / embedded inside the porous filling material, wherein detection channels extend inside the filling material to provide substantially straight paths extending from the gas sensor to predetermined locations within the housing, in particular to one or more of on-tank valves, thermal pressure relief devices and piping connections.

[0036] In embodiments, the thermal pressure relief device are connected by a common safety line that comprises a vent port in one of said housing panels.

[0037] In embodiments, the housing panels are solid panels defining a substantially sealed inner volume. The panels are made from a solid material, in particular steel, which can be considered gas tight. It is however advantageous that two panels have venting apertures, in particular the top and bottom panels. This allows the escape of leaking gas.

[0038] According to another aspect, the invention relates to an automotive vehicle comprising a front area and / or a load compartment and a tank assembly according to the present invention, wherein at least one panel of said housing delimits said front area or load compartment, said at least one panel being a solid, gas-tight panel. In embodiments, the bottom panel is arranged at floor level of the vehicle and / or the top panel is arranged at a roof level of the vehicle.

[0039] The vehicle may be a van, in which case the load compartment can be configured a cargo area or passenger area (with seats).

[0040] In embodiments, a gas sensor may be arranged in said front area and / or load compartment.

[0041] These and other embodiments of the invention are recited in the appended claims.P-DELPHI-456 / WO 5

[0042] Brief Description of the Drawings

[0043] Further details and advantages of the present invention will be apparent from the following detailed description of several not limiting embodiments with reference to the attached drawings, wherein:

[0044] Fig. 1 is a side cross-sectional view of an embodiment of the inventive tank assembly;

[0045] Fig. 2 is a top view of the internal of the tank assembly of Fig.1 ;

[0046] Fig. 3 is plot of quenching distance vs. hydrogen concentration at different pressures; and

[0047] Fig. 4 is a side cross-sectional view of another embodiment of the inventive tank assembly.

[0048] Description of Preferred Embodiments

[0049] The present invention pertains to a tank assembly designed for the storage of gaseous fuel. It is particularly suited for use in automotive vehicles that operate on gaseous fuels such as hydrogen, whether powered by a combustion engine or a fuel cell.

[0050] An embodiment of the tank assembly 10 is schematically illustrated in Figs.1 and 2. The tank assembly 10 comprises a plurality of gas tanks 12 that are arranged inside a common housing 20.

[0051] The gas tanks 12 may be conceived based on any appropriate technology. In particular, the gas tanks may be Type III or IV tanks, i.e. consist of a thin metal liner or a polymer liner wrapped with a composite material shell. They are typically designed to withstand high pressures, often up to 700 bar, to store sufficient quantities of gaseous fuel for practical vehicle range. The design of the gas tanks is not the focus of the invention and will therefor not be further discussed.

[0052] Conventionally, each gas tank includes an on-tank valve 14, OTV, that allows filling and discharging gas intro / from the gas tank 12.

[0053] Furthermore, each gas tank 12 is equipped with at least one thermal pressure relief device 16 (TPRD), which is a safety device installed on a gas tank to protect against the risks of over-pressurization due to high temperatures. As is known in the art, aP-DELPHI-456 / WO 6

[0054] TPRD is temperature-sensitive and activates when the surrounding temperature exceeds a predetermined threshold. Once activated, the TPRD allows the gas stored in the tank to escape in a controlled manner. TPRDs may use fusible plugs, burst disks, or other mechanisms to sense heat and release pressure.

[0055] In the present variant, each tank has three TPRDs 16. A TPRD line 18 connects the TPRDs with the interior of each gas tank 16. Common line 18.1 connects the TPRD lines 18 of each tank 12 and has a vent port 18.2 in panel 20.2.

[0056] The housing 20 includes a plurality of panels 20. i that define an internal volume 21 that accommodates the gas tanks together. In the example, the housing is of parallelepiped shape and 4 side panels 20.1 that connect the edges of rectangular top and bottom panels 20.2, 20.3.

[0057] In principle, the panels 20. i are solid, and do not have holes, gaps, or apertures that could compromise the enclosure. Accordingly, they define a closed space with an internal volume.

[0058] The housing 20 further accommodates the accessories / equipments of the gas tanks. These may particularly include one or more of:

[0059] - support elements (not shown) for the gas tanks;

[0060] - an interconnecting pipe 22 connecting the respective OTVs 14 of the tanks 12, typically acting as a manifold;

[0061] - a supply line 24 that branches off the interconnecting pipe 22 and through one of the panels 20. i, to supply hydrogen to the engine;

[0062] - any other accessory for the gas tanks.

[0063] The gas tanks 12 with their valves, pipes and accessories typically occupy most of the internal volume of the housing, but unoccupied space remains.

[0064] It will be appreciated that the unoccupied space inside the internal volume of the housing 20 is essentially completely filled with a porous filling material 26 that has a porosity sized to quench an ignition event in the internal volume 21 due to gaseous fuel leakage.

[0065] Essentially completely filled means that at least 95%, and up to 98, 99 and 100% of the remining space is occupied by the porous filling material 26. The remainingP-DELPHI-456 / WO 7

[0066] space is the part of the interior volume 21 that is not occupied by the gas tanks and their related accessories / equipment (which could be call void or unoccupied space, but is here in fact taken by the porous filling material 26). As a consequence, the porous filling material surrounds entirely (tightly / against) the tanks and accessories and extends up to (against) the inner sides of the panels and intervening partition walls.

[0067] As will be understood by those skilled in the art, the porous filling material 26, with the prescribed porosity, enables any gaseous fuel (due to leakage) to permeate into and through the porous filling material 26 that acts as ignition-quenching filling. The porosity of the filling material 26 is designed to quench, i.e. extinguish, any ignition due to gas inside the filling material. In particular the porosity is defined with respect to the quenching distance, which is conventionally defined as the minimum distance from a flame to a surface or obstacle at which the flame can continue to propagate. The quenching distance is influenced by factors such as fuel composition and pressure.

[0068] It is desired that the inner volume of the housing is essentially completely filled with the porous filling material, whereby the gas tanks together with any associated equipment are embedded and surrounded by the porous filling material. The idea here is that the entire volume within the housing is taken by the gas tanks and related components and by the porous filling material, to avoid any voids or gaps that could form gas pockets. Accordingly, the present tank assembly has an internal volume that is designed to inhibit flame propagation, thereby preventing explosive risk.

[0069] Fig. 3 is a plot of quenching distance vs. hydrogen concentration, for different pressures. As can be seen, at ambient pressure a quenching distance of 0.5 mm is the smallest quenching distance over the possible concentration ranges. By designing the filling material to present a porosity of 0.5 mm, one can basically prevent propagation of explosions over all concentration ranges and even in case of small overpressure.

[0070] Depending on the filling material and its manufacturing, the open porosity is due to pores, holes or recesses that communicate and form passages or channels within the body of filling material.P-DELPHI-456 / WO 8

[0071] In embodiments, porous filling material may be used that has an average effective passage diameter that is no greater than 0.50 mm, for example in the range 0.25 to 0.50 mm.

[0072] In embodiments, porous filling material may be used that has a porosity in the range of 50 to 100 PPI (Pores Per Inch).

[0073] The porosity characteristic may be measured according to the protocols and techniques defined in ISO 15901-2:2022.

[0074] Preferably, the pore density expressed in pores per inch is herein determined as a lineal pore density, by counting the number of pore openings intersected by a straight reference line of known length on a representative surface of the sample. The reference line is selected so as to intersect at least 20 pore openings.

[0075] A suitable polymer for the filling material is reticulated polyurethane foam. The filling material may include a plurality of foam elements that are tightly assembled together to form a continuous body of porous filing material inside the housing, to avoid voids where gas may collect (gas pockets).

[0076] In the shown embodiment, a plurality of partition walls 28 are arranged horizontally and vertically. They provide additional rigidity to the tank structure. They divide the unoccupied inner volume into sub-regions that are filled with the porous filing material, namely with the foam elements.

[0077] The use of several foam elements, indicated 26.1, is shown for the sake of exemplification in one of the sub-regions in Fig.1.

[0078] The partition walls 28 are made from porous metallic material, where the porosity is also sized to be less than or equal to a quenching distance of the gaseous fuel. In particular, the porosity is the same as the that of the filling material, or smaller. Preferably, the partition walls are made from a metal or metallic alloy having good thermal conductivity (e.g. greater than 150 W / m K), in particular selected from copper, copper allow, aluminum and aluminum alloy.

[0079] Reference sign 30 designates a gas sensor that is embedded within the porous filling material 26. A plurality of detection channels 32 are provided inside the filling material 26 to provide substantially straight gas flow paths extending from the gas sensor 30 to predetermined locations within the housing 20. This allows earlyP-DELPHI-456 / WO 9

[0080] detection of gas concentrations, and can be used to shut-down the system in case a leak is detected. The detection channels may namely extend from the gas sensor 30 to areas where there are connections, like at the OTV, TPRD, piping connections, etc. The detection channels may have a diameter ranging from 1.0 to 5.0 mm. In the present embodiment, as alluded above, all panels 20. i are normally solid, without apertures (gas tight). This is particularly true for the side panels 20.1 that can be at the interface with passenger or load compartments. It is however desired that the bottom and top panels are provided with an aperture 38, 40, to allow some air circulation and maintain the internal volume at atmospheric pressure. This allows flushing leaking gas.

[0081] The inventive tank assembly provides a closed containment for gas tanks that allows installation of the gas tank assembly inside vehicles. It is thus in contrast with the conventional approach where the tanks are arranged outside, for ensure passive ventilation.

[0082] Reference sign 34 schematically designates a load compartment of the vehicle on board of which the tank assembly 10 is mounted. As can be seen, the housing 20 partly delimits the load compartment 34 by one of its side panels 20.1, which is then a solid panel without any aperture, to provide a gas-tight separation wall with the compartment. For safety, a gas sensor 36 can be arranged inside the compartment 34.

[0083] Again, in this example all side panels 20.1 are solid panels without apertures / holes. In Fig.1 , the height of the load compartment is indicated H. The side panels hence extend over the height of the load compartment, i.e. the bottom panel 20.3 is integrated (essentially at same height) as the vehicle floor. Same at the top, where the top panel 20.2 is at the level of the roof.

[0084] In practice, the gas tank 10 can thus be integrated in a vehicle, in particular within or at the interface of a load compartment or passenger area, from which it is however sealed by the solid lateral panels 20.1.

[0085] In Fig.2, reference sign 42 indicates the vehicle front I driver area (dashed line area). The vehicle width is noted W. The illustrated embodiment corresponds to a vehicle such as a van, where the tank assembly is arranged at the rear of the front cabin 42 With the driver), hence at the interface with the load compartment 34. The loadP-DELPHI-456 / WO 10

[0086] compartment can be configured as a cargo area for containing parcels, equipment, etc., or as passenger area, with seats for passengers (mini-bus like).

[0087] It the shown embodiment the housing 20, resp. the tank assembly 10, does not extend over the entire width W of the vehicle. There may be an open passage (or not) from the load compartment to the vehicle front area 42. Alternatively, the housing 20, resp. the tank assembly 10, may extend over the entire width W.

[0088] Turning now to Fig. 4, an embodiment is shown that is vastly similar to that of Fig. 1. Here, however, the roof, namely top panel 20.2, is non-planar. Specifically, the top panel is shaped to define a highest point within the housing 20, which promotes accumulation of a light gas at the highest point. The highest point is preferably centrally located. In the embodiment, this can be achieved by using a convex shaped roof. In the example, the top panel 20.2 has a trapezoidal cross-section. In practice, the top panel 20.2 may e.g. be shaped as a truncated-pyramidal form or as a dome-shaped form.

[0089] The upper aperture 40 is positioned at the highest point of the roof. And the same is true for the vent port 18.2 of the TPRD line 18.

[0090] The gas sensor 30 is positioned centrally in the upper region of the convex roof. A remotely controllable fan 50 is arranged over the upper aperture, and can be selectively actuated to promote extraction of leaked gaseous fuel from within the housing 20.

[0091] The gas sensors 30 and 36 may be connected to a control unit that is configured to generate an alert signal when the detected gaseous fuel concentration exceeds a predetermined threshold TH1.

[0092] The fan 50 is normally off (not energized). The control unit may be configured to actuate (switch on / energize) the fan 50 when gaseous fuel concentration detected by sensor 30 exceeds a predetermined threshold TH2. Promoting ventilation of the housing 20 allows reducing the gaseous fuel concentration and improves safety.P-DELPHI-456 / WO 11

[0093] Pore density determination

[0094] As indicated above, preferred porous filling material may have a porosity -or rather pore density- in the range of 50 to 100 PPI.

[0095] This pore density is preferably determined as lineal pore count, i.e. a measure of the number of open pores (pore windows) intersected by a straight reference line of known length on a representative surface or image of the foam. The pore density is here expressed as pores per inch, PPI.

[0096] A specimen of the porous material is prepared to present a planar surface representative of the bulk structure. The planar surface is observed directly under magnification (e.g. 5 to 25x) or via a captured image having a calibrated scale. A straight reference line of length L is positioned on the image / surface in a manner that is representative (e.g., at a random location or by systematic random sampling). The number N of pores intersected by the reference line is counted, where a pore is considered “intersected” when the reference line passes through a pore opening bounded by struts. The pore density, in PPI, is then calculated as as the ratio of the number of pore openings N to the length L (in inches) of the reference line:

[0097] Pore density = N / L

[0098] The measurement may be repeated for a plurality of reference lines at different locations and / or orientations on the specimen, and the reported pore density is the arithmetic mean of the replicate values (with standard deviation if desired).

[0099] The reference line length is preferably selected such that at least 20 pore openings are intersected, preferably at least 40 pores, in order to obtain a statistically representative average. Multiple measurements may be taken at different locations and / or orientations, and the reported pore density may be an arithmetic mean of the individual measurements.

[0100] Additionally, the reference line length may be selected so as to intersect a statistically representative number of pores; by way of example, the reference line may have a length of 1 inch, or 2 inches, although other line lengths may be used provided that a sufficient number of pore openings are counted to obtain a representative average.

Claims

P-DELPHI-456 / WO 12Claims1. A tank assembly for gaseous fuel, in particular for a fuel delivery system of an internal combustion engine, comprising:one or more tanks (12) configured for containing gaseous fuel;a housing (20) having a plurality of panels (20. i) that define an internal volume (21);characterized in that the one or more tanks (12) are arranged inside the housing (20), and remaining space is filled with a porous filling material (26, 26.1) having a porosity that is sized to quench an ignition event in the internal volume due to gaseous fuel leakage.

2. The tank assembly according to claim 1 , wherein said porous filling material (26, 26.1) has a porosity with a characteristic diameter that is less than or equal to a quenching distance of the gaseous fuel.

3. The tank assembly according to claim 1 , 2 or 3, wherein within said porous filling material (26, 26.1) has a porosity with an average effective passage diameter that is no greater than 0.50 mm.

4. The tank assembly according to any of the preceding claims, wherein within said porous filling material (26, 26.1) has a porosity in the range of 50 to 100 pores per inch.

5. The tank assembly according to any of the preceding claims, wherein said porous filling material is a monolithic material or a combination of materials.

6. The tank assembly according to any of the preceding claims, wherein said porous filling material consists of a single material type and forms a monolithic, continuous volume filling the remaining space.

7. The tank assembly according to any of the preceding claims, wherein said porous filling material consists of a plurality of porous elements (26.1) that are shaped to collectively fill the remaining space.P-DELPHI-456 / WO 138. The tank assembly according to claim 7, wherein said porous elements (26.1) are of the same composition.

9. The tank assembly according to any of the preceding claims, wherein said porous filling material, respectively porous elements, are selected from the group consisting of a reticulated lattice, a reticulated foam, and an open-cell foam.

10. The tank assembly according to any of the preceding claims, wherein the porous filling material is made from a metal-based material, a polymer-based material, or of a composite material.

11. The tank assembly according to claim 1 , wherein said porous filling material is a polymer foam, in particular a reticulated polyurethane foam.

12. The tank assembly according to any of the preceding claims, wherein a plurality of partition walls (28) made from porous metallic material extend inside the internal volume and divide the latter into a plurality of sub-volumes, said porous metallic material having a porosity similar to said porous filling material, or smaller.

13. The tank assembly according to claim 12, wherein a plurality of said partition walls extend vertically, parallel to one another, between opposite side walls; and / or a plurality of second partition walls extend horizontally, parallel to one another, between opposite side walls.

14. The tank assembly according to claim 12 or 13, wherein said partition walls are made from a metal or metallic alloy having good thermal conductivity, in particular selected from copper, copper allow, aluminum or aluminum alloy.

15. The tank assembly according to any of the preceding claims, wherein each gas tank comprises one on-tank valve and at least one thermal pressure relief device, supply piping connecting the on-tank valves and safety piping interconnecting the thermal pressure relief devices.P-DELPHI-456 / WO 1416. The tank assembly according to any of the preceding claims, further comprising at least one gas sensor embedded inside the porous filling material, wherein detection channels extend inside the filling material to provide substantially straight paths extending from the gas sensor to predetermined locations within the housing, in particular to one or more of on-tank valves, thermal pressure relief devices and piping connections.

17. The tank assembly according to any of the preceding claims, wherein said thermal pressure relief device are connected by a common safety line that comprises a vent port in one of said housing panels.

18. The tank assembly according to any of the preceding claims, wherein said housing panels are solid panels defining a substantially sealed inner volume.

19. The tank assembly according to any of the preceding claims, wherein the housing comprises top and bottom panels provided with a venting aperture.

20. The tank assembly according to claim 19, wherein the top panel forms a roof defining a highest point and a venting aperture is arranged in the region of highest point; wherein the top panel forms a convex-shaped roof, in particular shaped as a truncated-pyramidal form or as a dome-shaped form.

21. The tank assembly according to claim 19 or 20, wherein a fan is arranged at the venting aperture to permit selective venting assistance.

22. The tank assembly according to claim 21 when depending on claim 16, wherein a control unit is connected to the gas sensor and is configured to actuate the fan when a detected gas concentration exceeds a predetermined threshold.

23. The tank assembly according to any of the preceding claims, wherein each tank includes a thin metal or polymer liner wrapped with a composite material shell.

24. An automotive vehicle comprising a front area and / or a load compartment and a tank assembly according to any of the preceding claims, wherein at least one panel of said housing delimits said front area or load compartment, said at least one panel being a solid, gas-tight panel.P-DELPHI-456 / WO 1525. The automotive vehicle according to the preceding claim, wherein the bottom panel is arranged at floor level of the vehicle and / or the top panel is arranged at a roof level of the vehicle.

26. The automotive vehicle according to the preceding claim, further comprising a gas sensor in said front area or load compartment.

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