Patent Description:
Of particular interest are heavy load vehicles such as trucks. Trucks in general are used to transport heavy loads over long distances. Particularly in case of heavy duty long applications so-called tractor semi-trailer combinations are used in which the tractor vehicle pulls and partly supports the payload that is packed onto the semi-trailer.

The long travelling distances with a target of more than <NUM>, of these typical long haulage tractor semi-trailer combinations require large amounts of fuel on board of the vehicle. Especially when alternative fuel sources are used such as hydrogen, the ability to carry sufficient quantities of fuel becomes even more important due to the fairly poor volumetric energy density in comparison to conventional fossil fuels (like diesel). Even more challenging becomes a layout wherein sufficient power is available, for extended periods of time, for a long-haul truck or tractor semi-trailer combination comprising an electrical driveline, an electric energy storage battery system, a hydrogen storage system and a plurality of fuel cell devices <CIT> discloses a truck with an electric driveline, battery and hydrogen storage systems and fuel cell devices.

To increase the volumetric energy density of these hydrogen based fuels normally gaseous hydrogen is pressurized and put into robust thick walled cylindrical container units that can withstand these high internal pressures. Pressure ranges typically from several bars in cryogenic conditions, to about <NUM>-<NUM> bar for storage at room temperature. To minimize the weight penalty of a firm and heavy high pressure resistant tank construction so called class IV carbon fibre reinforced plastic tanks are applied. These cylindrically shaped plastic tanks provide a new challenge for the commercial vehicle manufacturing industry to install these tank units on their trucks as replacement for the well-known rectangular sheet metal manufactured ambient pressure filled diesel tanks in the quest to offer sufficient driving range without the need for intermediate refuelling stops at gasoline shops (with currently lacking refuelling infrastructure). These large volume hydrogen tank units are typically placed left and right of the chassis (in between the front and rear wheels) and behind the cabin wall (in front of the semi-trailer). As a consequence only the remaining space in between and below the chassis rails is available to accommodate the electrical driveline, an electric energy storage battery system and a plurality of fuel cell devices.

Fuel cell devices are typically designed as complete charge generating systems, wherein, additional to one or more charge generating portions, also referred to as fuel cell stacks; one or more auxiliary portions to control hydrogen and air flow to the generating portion, also referred to as Balance-of-Plant (BOP), are provided. Such auxiliary portions at least comprise pump units, and air compressor and cooling units, to keep the fuel cell in a proper conditioned form as well as DC-DC converters to connect the fuel cell stack to the high voltage battery system to compensate this electrical interconnection for voltage differences and fluctuations in the actual fuel cell generating portion. The fuel cells may well be sensitive to acceleration impact, which could damage the charge generating portions, in particular the membrane and/or auxiliary portions when not specifically designed for the harsh vehicle environment of a vibrating truck chassis. In addition, due to the charge generating process, substantial packaging space is needed in order to allow for generating electric output power of at least <NUM> kW; and preferably even multiples thereof, up to even <NUM> kW. This poses challenges for proper packaging of fuel cells in vicinity of a large volume hydrogen storage.

It is an objective of the claimed invention to solve one or more problems faced in the state of the art.

According to the invention, a truck or tractor semi-trailer combination comprises an electrical driveline, an electric energy storage battery system, hydrogen storage system and a plurality of fuel cell devices. Each fuel cell device comprises a charge generating portion; and one or more auxiliary portions auxiliary to the charge generating portion. The truck is provided with a pair of elongated chassis beams extending along the length of the truck, wherein a storage space is defined between the chassis beams; a front side bridge member laterally extending across the chassis beams; and a rear side cross beam. At least one storage unit is provided that houses a fuel cell device, comprising one or more mounts for suspending said storage unit relative to the chassis beams. The storage unit further comprises an interface module for coupling an air supply duct, an hydrogen supply duct and a water drain duct. The storage unit has a top part extending between the chassis beams in said storage space; and a bottom part extending below the chassis beams and extending at least on one side laterally across the chassis beams.

<FIG> shows a realistic embodiment of a truck (or tractor), wherein a storage space <NUM> is defined between the chassis beams; a front side bridge member laterally extending across the chassis beams; and a rear side cross beam an additional elongated pressure vessel <NUM> is oriented in horizontal position adjacent the at least one pressure vessel <NUM> in upstanding position and in near vicinity of the projected fifth wheel location; above the chassis members. The position of the pressure vessels is beneficial due to the efficient use of space, but not mandatory; other spaces may be suitable. A pressure vessel <NUM> is preferably located below on a (projected) bottom of the semi-trailer at the vertical location of the fifth wheel and above the tractor chassis members. Furthermore, additional elongated pressure vessels <NUM>, for reaching a driving range of more than <NUM> or more, are provided in the bottom framework (or chassis) of the tractor, in particular, in a space provided between front and rear wheels and at the outside (in parallel to the longitudinal centreline of the tractor) where normally, in conventional combustion engine driven trucks, the diesel tanks and the exhaust aftertreatment system are installed. A battery pack <NUM>, that realistically weighs at least about <NUM> - <NUM> kgs, may preferably be placed with its gravity centre on or near the front axle, as this is considered to be the heaviest component (highest gravimetric density) in a fuel cell electric vehicle to allow for more payload carry ability of the rear axle. Note that the maximum axle loads are legally bounded (e.g. rear axle <NUM>,<NUM> ton and front axle <NUM>,<NUM> ton as an average indication for European countries). The center space in the bottom of the tractor and in the middle between the chassis members may be used for housing fuel cell systems <NUM>, where normally, in conventional trucks, central drive shafts or trains may be housed. In the proposed solution according to <FIG> the electric motors that drive the truck may be arranged as a so-called e-axle <NUM> (having the electric motors directly integrated in the rigid rear axle advantageously eliminating the need for a central driveshaft and differential gear system with a complex angle transmission), advantageously making packaging space available to place the fuel cells in the middle of the chassis.

In more detail, <FIG> shows a storage unit <NUM> provided in the storage space indicated in <FIG>. The storage unit houses a fuel cell device (not shown) and comprises one or more mounts <NUM> for suspending said storage unit relative to the chassis beams <NUM>. The storage unit <NUM> further comprises an interface module <NUM> e.g. for coupling an air supply duct, an hydrogen supply duct and a water drain duct (see subsequent figures). A virtual plane <NUM> divides a top part <NUM> extending between the chassis beams <NUM> in said storage space <NUM>; and a bottom part <NUM> extending below the chassis beams and extending at least on one side laterally across the chassis beams <NUM>.

Depending on the configuration of cross beams <NUM>, <NUM> and/or bridge members <NUM>, storage unit <NUM> may be suspended on each side in length direction to one or more of these cross beams.

In the alternative, <FIG> shows storage unit <NUM> provided extending underneath a middle cross beam <NUM> (in the art known as K-cross member).

In an advantageous configuration four mounts are arranged to carry said storage unit, having two front mounts <NUM> in an extended lateral position on a storage unit front side, and two rear mounts <NUM> in an adjacent position on a storage unit rear side. The two front mounts <NUM> at the adjacent rear side position are preferably placed close to each other (short lateral distance) to mimic the functionality of a so-called three point suspension advantageously absorbing chassis torsional flex deformation without dynamically loading these mounts. Having the two mounts at the front side of the storage box at large lateral inter distance contributes to reduced relative twist angles between local rigid chassis structure the storage box at this front end location. The latter is beneficial to relieve the impact on the flexible interfacing channel work at the front end (e.g. air intake, water drain and hydrogen feed ducts) In a further advantageous embodiment, the storage unit is elastically suspended with a heave, pitch and roll eigenfrequency that is tuned to be distinct of the primary eigenfrequency typically ranging between <NUM> and <NUM> of the rear axle unsprung mass. This can for example be achieved by a ratio of the axial stiffness and the lateral stiffness is more than <NUM>, preferably more than <NUM>, or even in a range of <NUM>-<NUM>. In the alternative, depending on the weight of the storage box, in relation to the stiffness of the mounts, a fairly rigid mounting structure of the hydrogen vessels may be placed behind the cabin, being close the front end of the storage box. This can be advantageous for relatively heavy storage box weights, e.g. exceeding <NUM>, so that the risk of picking up vibrations from the unsprung mass are low if a stiff mount is used, with stiffness eg. higher than <NUM> N/mm in the front. This improves mounting characteristics for mounting the air supply, hydrogen supply and water drain. Conversely, the rear end of the storage box may be mounted with a stiffness that is relatively lower, e.g. lower than <NUM> N/mm, in particular between <NUM> and <NUM> N/mm to accommodate some torsional and vertical vibration. This has an advantage that a very stable interface can be provided for the storage box and while having a low vibrational impact.

A single integrated double suspension mount provides an advantage that impact of the rear wheels is only partly translated in a torsional rotational movement of the storage unit <NUM> along an axis that aligns with the vehicles length direction. By having on each side a double suspension, risk of mounting failure is minimized (as opposed to a single mount), reduces the complexity and costs of said mounts as they can manufactured identical and the loads per mounts are reduced advantageously limiting the design volumes of these units. By having on the front side two mounts at an extended lateral position, chassis torsion between chassis members <NUM> and the storage unit <NUM> can be minimized, which is beneficial for the position of the depicted interface module <NUM>, that benefits from a stable connection between the storage unit <NUM> and corresponding coupling of an air supply duct, an hydrogen supply duct and a water drain duct to the storage unit <NUM>. In a further advantageous configuration, all mounts are provided on the interior of the storage space, that means, not extending at least not laterally, to provide room for horizontal hydrogen vessels <NUM> (see <FIG>). While the bridge member <NUM> shown in <FIG> is different from disclosed cross beams <NUM>, <NUM> a bridge member may also be formed by a cross beam, as long as it provides a lateral connection between the chassis beams <NUM>. Furthermore, the rear suspension cross member <NUM> may be part of a larger structure, e.g. a suspension structure for the rear axle.

It is noted that the storage unit <NUM> may be formed extending into said storage space <NUM> with an L-shape or an inverted T-shape. A T-shape has the advantage of a greater energy generating volume in the space <NUM> underneath the chassis beams <NUM>; while a L-shape (effectively using only one lateral extending side underneath the chassis beams <NUM>) may provide for additional air ducts sideways connecting to the storage unit, or additional high voltage cabling or other tubing that needs to be guided alongside the storage units <NUM>.

<FIG> shows an alternative mount structure, with L-shaped brackets <NUM> mounted to the chassis beams <NUM>. Section A is shown partly enlarged and rotated, so that it is visible that front mounts <NUM> are supported on a bottom leg of the L-shaped bracket <NUM> to carry the weight of the storage unit <NUM> acting on said mounts <NUM> (in closed form manner opposing of gravity). This has the advantage that the storage unit <NUM> is still supported by the L-shaped bracket <NUM> in an inadverted event of failure of the mount <NUM>, such as loosening of the fixation bolts. The storage unit <NUM> can be efficiently removed by removing the L-shaped brackets <NUM> from the chassis beams <NUM> and lowering the storage unit <NUM>. Furthermore the structure does not have protruding elements that could interfere with system components (e.g. battery elements or hydrogen tanks) mounted lateral to the storage unit <NUM>.

<FIG> shows several configuration layouts for the storage unit <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>.

In <FIG>, storage unit <NUM>-<NUM> comprises at least one auxiliary fuel cell portion <NUM> shaped to at least extend partly in the storage unit top part <NUM>, and wherein one or more charge generating portions <NUM>, also known as fuel cell stacks are provided in the storage unit bottom part <NUM>. The auxiliary fuel cell portion is also known as the balance of plant (BOP) and typically comprises water pumps, inverters, control units, humidifier, etc. Additionally are show DC-DC converters <NUM>, air compressor <NUM> and intercooler <NUM> as exemplary components of the auxiliary fuel cell portion <NUM>. By way of example, <FIG> houses a <NUM> x <NUM> kW Fuel Cell stack <NUM> in the lower part <NUM> that extend laterally across chassis beams <NUM>. An advantage of this configuration is that the fuel stacks can be reached in by supply and drain tubing (hydrogen, air, water) in the top part <NUM> fairly conveniently.

In <FIG>, storage unit <NUM>-<NUM> comprises at least one charge generating portion (fuel cell stack) <NUM> shaped to at least extend partly in the storage unit top part <NUM>. The auxiliary portions <NUM>-<NUM>, <NUM>-<NUM> are provided at least on one side of the charge generating fuel cell portion <NUM> in the storage unit bottom part <NUM>.

In the shown example, the fuel cell stack <NUM> is formed by two stacked fuel cells, one of them extending between the chassis beams (not shown); and two additional stacked cells on opposite sides of a storage space portion <NUM> extending underneath a further central cross beam.

In <FIG> a stack <NUM>-<NUM>. <NUM> extends in the length direction of the vehicle, with each fuel cell extending in the storage unit top part <NUM>.

<FIG> in more details shows an exemplary arrangement where it becomes clear how the interface module, provided on a top front side of the storage unit connects to an air supply duct <NUM> from an air intake system <NUM>. In the embodiment, air duct <NUM> is provided by a wide diameter/low resistance duct that connects to an air intake <NUM> on the front side of the truck via filter <NUM> that is positioned in the front right end corner of the truck in front of the front wheels and below and outsides (in lateral direction) of the chassis beams. A relatively large volume is occupied by such a dedicated (serviceable) filter unit to minimize the resistance to air flow through the filter itself. The spot in the right front bottom corner of the truck is beneficial to avoid clearance problems with other needed vehicle components. From this location on a channel system back up making the connection an air intake duct (connection with exterior) to a higher position integrated in top region of the front grille needs to be installed whilst avoiding resistance.

<FIG> shows how air duct connects to the interface module <NUM> of the storage unit. In the interface module, additional arrangements may be provided to provide for water exhausts <NUM>, hydrogen inlets, coolant tubing and high-voltage connections (not shown). Exemplary design rates for the air duct may be to provide for air flow rates up to <NUM>/s at ambient temperature and atmospheric pressure. The main channel resistance will then be caused by an air filter, which may induce pressure differences up to <NUM> kPa (in end of service life state and despite the fairly large volume filter unit).

<FIG> further shows a truck wherein the water drain duct <NUM> extends along the vertical elongated hydrogen vessels <NUM>; preferably having the water drain duct integrated in a cowl <NUM> enclosing the vertical elongated hydrogen vessels.

Claim 1:
A truck or tractor semi-trailer combination comprising an electrical driveline, an electric energy storage battery system, hydrogen storage system and a plurality of fuel cell devices, each fuel cell device comprising a charge generating portion (<NUM>); and one or more auxiliary portions (<NUM>) auxiliary to the charge generating portion, wherein the truck is provided with a pair of elongated chassis beams (<NUM>) extending along the length of the truck, wherein a storage space (<NUM>) is defined between the chassis beams (<NUM>); a front side member (<NUM>) laterally extending across the chassis beams (<NUM>); and a rear side cross beam; characterized in that at least one storage unit (<NUM>) is provided that houses a fuel cell device, said storage unit (<NUM>) comprising one or more mounts (<NUM>) for suspending said storage unit (<NUM>) relative to the chassis beams (<NUM>); and further comprising an interface module (<NUM>) for coupling an air supply duct (<NUM>), an hydrogen supply duct and a water drain duct (<NUM>), wherein the storage unit (<NUM>) has a top part (<NUM>) extending between the chassis beams (<NUM>) in said storage space (<NUM>); and a bottom part (<NUM>) extending below the chassis beams (<NUM>) and extending at least on one side laterally across the chassis beams (<NUM>).