D E S C R I P T I O N

Trailer and Vehicle with a Trailer

TECHNICAL FIELD

The invention relates to a trailer and a vehicle with a trailer according to the preambles of the independent claims.

BACKGROUND OF THE INVENTION

Vehicles fed with new fuels like dimethyl ether (DME), liquefied propane gas (LPG), natural gas (NG), ethanol and the like need a larger tank volume compared to tanks for diesel engines. For instance, DME needs double tank volume compared to diesel.

It is known in the art of trucks to extend the volume of a tank of a tractor by mounting an additional fuel tank on a trailer attached to the tractor.

A fuel transfer system for tractor trailer vehicles is described in US 3 677 284 A. A large auxiliary fuel supply tank is carried by the trailer of the tractor-trailer vehicle. A fuel supply system proyides a transfer of fuel from the auxiliary tank on the trailer to the tank of the tractor. It is also proposed in one embodiment to supply the fuel from the auxiliary tank directly to the diesel engine.

US 6 508 265 A describes a dual fuel tank system for use in automotive applications. Fuel from the second fuel tank is communicated to the first fuel tank by use of a fuel pump.

EP 1 577 143 A1 discloses a dual tank assembly comprising two tanks attached to the chassis frame behind the rear axles. When used in articulated vehicles, the tank is located in a protected area between the tractor and the trailer. SUMMARY OF THE INVENTION

It is an object of the invention to provide a trailer which provides an improved range of a tractor-trailer vehicle particularly supplied with a fuel having a higher flammability than diesel or petrol. Another object of the invention is to provide a vehicle with an improved range.

The objects are achieved by the features of the independent claims. The other claims and the description disclose advantageous embodiments of the invention.

A trailer for a vehicle, particularly a truck, is proposed comprising at least one fuel tank being arranged below an underside of the trailer wherein the fuel tank is equipped for a fuel with a higher flammability than diesel or petrol wherein the fuel tank has a fluid connection to an engine of the vehicle. Favourably, a sufficient volume of fuel can be provided even for fuels which have a lower density than diesel or petrol. Increasing the tank volume on the tractor side is hard without reducing obligatory safety precautions for the tank mounting. The invention allows for improving the range of the tractor-trailer vehicle without compromising available space for cargo and/or crash protection in accidents and without the need to stop for re-fuelling too often. The at least one tank can be mounted on the trailer in a well protected area. Particularly, multiple flow connections can be provided between the trailer tank and the engine, such as feed and return lines of the fuel.

According to a favourable embodiment of the invention, the shell of the fuel tank can have a clearance at least to the longitudinal and transversal outer trailer sides. Thus it can be avoided that the tank receives unwanted impact by objects approaching the vehicle. The frame rails of the trailer protect the tank in a crash case.

According to a further favourable embodiment of the invention, an underride protection can be arranged at longitudinal and/or transversal sides with a distance to the respective sides. The underride protection can prevent a vehicle to move under the trailer. By the distance of the underride protection to the tank it can be avoided that the underride protection penetrates the shell of the tank. According to a further favourable embodiment of the invention, the fluid connection attached to the tank can comprise a flexible hose. Favourably, even in a crash case the fluid connection cannot penetrate the shell of the tank.

According to a further favourable embodiment of the invention, the tank can be attached to the trailer by one or more straps. Favourably, even in a crash case the attachment device cannot penetrate the shell of the tank or break from the shell causing damage to the shell. Generally, objects protruding from the tank are avoided thus reducing the risk of breaking those objects and damaging the tank. Expediently, the straps should not be too long so that the tank can be securely placed below the frame rails.

According to a further favourable embodiment of the invention a safety valve can be provided for automatically disrupting a fuel flow between the tank and its fuel connections when a connection between the trailer and the vehicle is opened. Leakage of the fuel in an accident can be minimized. Advantageously, such a safety valve can be provided for each tank in the trainer and/or the tractor. The safety valve can be located close to the tank in a hose connected to the tank.

According to a further favourable embodiment of the invention a safety valve can be provided for automatically disrupting a fuel flow between the tank and its fuel connections when a flow in the connection hose is detected which is higher thanja predetermined limit. Such safety valves are known from hydraulic hoses and the like. A fuel flow in the hose which is too high may indicate a defect hose, and the tank is closed accordingly. Advantageously, such a safety valve can be provided for each tank in the trainer and/or the tractor. The safety valve can be located close to the tank in a hose connected to the tank.

According to a further favourable embodiment of the invention, a safety valve can be provided for automatically closing the tank fuel flow connections in case of an impact on the tank. Leakage of the fuel can be avoided According to a further favourable embodiment of the invention, a safety valve can be provided for releasing the fuel in a controlled way to a safe location of the trailer for burning the fuel in a controlled way when the safety valve opens. Accumulation of the fuel can be avoided. The fuel can be released in small amounts and neutralized by burning to less harmful components in a controlled way.

According to a further favourable embodiment of the invention, the tank can comprise a multitude of sections separated by partitions which can be closed in case of an impact on the tank. The crash safety can be improved. Even if one section is damaged, the fuel in the other sections can be safely kept in the tank or discharged in a safe and controlled way.

According to a further favourable embodiment of the invention, the shell of the tank can have an elliptic cross section. The cross section allows handling high pressures inside the tank. The shape can be easily manufactured.

According to a further favourable embodiment of the invention, the fluid connection of the tank can be connectable to a feed pump in the vehicle in a way that when the trailer is coupled to the vehicle, the tank is an integral part of the fuel system of the vehicle. Favourably, the fuel on the trailer can be directly fed to the engine avoiding a time consuming transfer into a tractor mounted tank

According to a further favourable embodiment of the invention, a valve can be provided for balancing fuel levels between at least two tanks on the vehicle. The fuel can then be discharged to the engine in a reliable way. Overfilling of a tank beyond a safe level can be avoided. The distribution of fuel among the tanks can be controlled as desired. For instance, when it is expected that the trailer is going to be left behind for unloading etc. the vehicle management system can plan ahead and let most of the fuel be consumed out of the trailer's tank. Favourably, for balancing a check valve can be arranged in a fluid connection between the tanks providing a fuel flow from the trailer mounted tank to the tractor mounted tank and blocking the reverse direction. According to a further favourable embodiment of the invention, the tank can be adapted for cooling the fuel. The tank can be operated safely. Alternatively or additionally the connection hose between the trailer-mounted tank and the tractor- mounted tank can be equipped for cooling.

According to a further favourable embodiment of the invention, cooling fins oriented in a longitudinal direction of the trailer or the air flow around the tank can be provided on the tank. Favourably, the tank can be cooled by the relative air motion during driving. This is particularly advantageous for a DME tank. Alternatively or additionally the connection hose between the trailer-mounted tank and the tractor-mounted tank can be equipped with cooling fins.

According to another aspect of the invention, a vehicle is proposed comprising a tractor and a trailer comprising at least one tank mounted on the trailer according to any feature described above. Favourably, the vehicle can make use of fuels with a higher flammability than diesel or petrol, lower density and nevertheless have a sufficient range for operation of the vehicle.

According to a favourable embodiment of the invention, a fluid connection of the tank can be connectable to a feed pump in the vehicle in a way that when the trailer is coupled to the vehicle, the tank is an integral part of the fuel system of the vehicle. Favourably, the fuel on the trailer can be consumed avoiding a time consuming transfer into a tractor mounted tank.

According to a further favourable embodiment of the invention, a valve can be provided to balance a fuel level in one or more tanks mounted in the tractor and the one or more tanks mounted on the trailer.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention together with the above-mentioned and other objects and advantages may best be understood from the following detailed description of the embodiments, but not restricted to the embodiments, wherein is shown schematically:

Fig. 1 an example embodiment in a side view of a tractor-trailer vehicle according to the invention;

Fig. 2a, 2b a side view (Fig. 2a) and a front view (Fig, 2b) of an example embodiment of a preferred trailer according to the invention; Fig. 3 an example embodiment of a tank comprising sections according to the invention; and Fig. 4 a front view of a preferred tank comprising cooling fins.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

In the drawings, equal or similar elements are referred to by equal reference numerals. The drawings are merely schematic representations, not intended to portray specific parameters of the invention. Moreover, the drawings are intended to depict only typical embodiments of the invention and therefore should not be considered as limiting the scope of the invention.

Fig. 1 depicts schematically a side view of a tractor-trailer vehicle 100, particularly a truck, comprising a tractor 102 and a trailer 110. A Jank 10 equipped for a fuel with a higher flammability than diesel or petrol is mounted on the trailer 110. Of course, more than one tank 10 can be attached to the trailer 110. The fuel tank 10 is arranged below an underside 120 of the trailer 110. A fluid connection 50 to an engine of the vehicle 100 comprising a flexible hose is attached to the tank 10. Preferably, components which could penetrate the tank 10 are well kept away from the tank 10. Further, attachment components attached to the tank 10 are embodied in a way that they cannot break loose and cause damage to the tank 10. Particularly, flexible and soft materials can be used at and close to the tank. Preferably, the tank 10 can be attached to the trailer with one or more straps (not shown). _

The fluid connection 50 of the tank 10 is connectable to a feed pump (not shown) in the vehicle 100 in a way that when the trailer 110 is coupled to the vehicle 100, the tank 10 is an integral part of the fuel system of the vehicle 100.

As shown in Figs. 2a and 2b in a schematic sketch, the shell 12 of the tank 10 has a clearance 32a to a first transversal trailer side 112 and a clearance 32b to a second transversal trailer side 116 opposite to the first transversal trailer side 112, a clearance 34a to a first longitudinal trailer side 114 and a clearance 34b to a second longitudinal trailer side 118 opposite to the first transversal trailer side 114.

Consequently, the tank 10 is completely arranged within the trailer 110 which improves the crash protection for the tank 10. The protection of the tank 10 can be improved further if one or more underride protections (not shown) are mounted at one or more trailer sides 112, 114, 116, 118. Preferably, the one or more underride protections are arranged with a distance to the respective sides 112, 116, 114, 118 as well as to the tank, thus avoiding a penetration of the shell 12 in a crash.

Favourably, a safety valve (not shown) can be provided for automatically disrupting a fuel flow between the tank 10 and the rest of the fuel system when a connection between the trailer 110 and the vehicle 100 is opened. An additional safety valve (not shown) can be provided for automatically closing the fuel connections of tank 10 in case of an impact on the tank 10. Both safety features can be integrated in a single safety valve.

Favourably, a safety valve can be provided for releasing the fuel in a controlled way to a safe location of the trailer 110 for burning the fuel in a controlled way when the safety valve opens.

Fig. 3 depicts an example embodiment of a preferred tank structure. The tank 10 comprises a multitude of sections 14a, 14b, 14c between a first and a second front face 20, 22, separated by partitions 16a, 16b. The partitions 16a, 16b can be closed in case of an impact on the tank 10. If one of the sections is damaged, the fuel can be safely kept inside the other sections, thus minimizing a leakage of the fuel.

The shell 12 of the tank 10 may have a circular or an elliptic cross section. The circular or elliptic cross section is favourable for a medium with high pressure inside the tank 10.

Fig. 4 illustrates a preferred embodiment in which the tank 10 is equipped for cooling the fuel. Cooling fins 40 can be arranged at the outer circumference of the tank 10 and/or the hose connecting the tank 10 to the tractor 102. The cooling fins 40 can be arranged all over the tank 10 and/or hose or arranged in portions. Favourably the cooling fins are arranged in a longitudinal direction of the tank 10 so that during driving the relative air motion can remove heat from the cooling fins 40.