TECHNICAL FIELD The invention relates to an arrangement for facilitating evacuating evaporated liquefied gas of a liquefied gas fuel system of a vehicle. The invention also relates to a vehicle.

BACKGROUND ART Alternative fuels such as natural gas and biogas are being introduced in vehicles such as heavy vehicles. For this purpose fuel systems for compressed natural gas, CNG and compressed biogas CBG and fuel systems for liquefied natural gas LNG and liquefied biogas LBG are being developed.

Systems for liquefied gas, i.e. LNG and LBG, require handling of relatively low temperatures, e.g. -130 degree Celsius at 10 bar for LNG, requiring certain conduits for transporting the liquefied natural gas and a certain tank for housing the fuel. When the vehicle is standing still and the engine is not operating the pressure in the tank will increase due to temperature increase in the tank. Therefore the system for liquefied gas is provided with a relief valve which according to an embodiment is set to open at 16 bar for evacuating evaporated gas.

The fuel tank/tanks for liquefied gas systems are usually arranged along and in connection to the vehicle frame. The evaporated gas is configured to be evacuated via a so called boil-off pipe connected to the fuel tank. The gas needs to be evacuated at a certain height. The boil-off pipe is further not allowed to project laterally or upwardly from the vehicle. For trucks the boil-off pipe is therefore usually arranged behind the cab of the truck. For trucks having a tiltable cab, i.e. cabs arranged to be tilted forwardly, the boil-off pipe is according to a variant arranged to be connected to a vertical member arranged in connection to and at a distance from the rear side of the cab to avoid influence from the tilting.

Such a solution, however, takes up space behind the cab which otherwise could be used for overhang or semi-trailer in order to optimize the length of the load carrying part of the vehicle.

Therefor it is desired to attach the boil-off pipe to the rear side of the cab. By thus arranging the boil-off pipe to the rear side of a tiltable cab an arrangement for facilitating evacuating evaporated liquefied gas of the liquefied gas fuel system taking the fact that the boil-off pipe is moved relative to the tank when the cab is tilted.

Arrangements for facilitating automatic connection between cab mounted boil- off pipe and chassis mounted tank when cab is moved from tilted to non-tilted positon are known.

There is however a need to provide an arrangement for further facilitating evacuating evaporated liquefied gas of a liquefied gas fuel system of a vehicle having a tiltable cab.

OBJECTS OF THE INVENTION

An object of the present disclosure is to provide an arrangement for facilitating evacuating evaporated liquefied gas of a liquefied gas fuel system of a vehicle.

Another object of the present invention is to provide a vehicle comprising such an arrangement. SUMMARY OF THE INVENTION

These and other objects, apparent from the following description, are achieved by an arrangement and a vehicle as set out in the appended independent claims. Preferred embodiments of the arrangement are defined in appended dependent claims.

Specifically an object of the invention is achieved by an arrangement for facilitating evacuating evaporated liquefied gas of a liquefied gas fuel system of a vehicle. The vehicle has a tiltable cab and a vehicle chassis, the cab being movably connected to the vehicle chassis in a non-tilted position of the cab. The fuel system has a chassis-mounted liquefied gas fuel tank for providing fuel to the engine of the vehicle, and a boil-off pipe. Evaporated gas is arranged to be evacuated from the tank via the boil-off pipe at a certain tank pressure. The boil-off pipe is attached to the rear side of the cab. The arrangement is configured to allow evaporated gas from the tank to be evacuated through the boil-off pipe in the non-tilted position. The arrangement comprises a downwardly open bottle configuration as a lower end connection of the boil-off pipe and a tank pipe member attached to the tank for conveying evaporated gas from the tank. The bottle configuration and the tank pipe member are configured so that, when the cab is moved from the tilted to the non-tilted position, a portion of the tank pipe member is introduced into the bottle configuration through its lower opening and positioned in the bottle configuration so that gas evaporated from the tank is introduced into the bottle configuration via the tank pipe member and evacuated through the boil-off pipe.

Hereby the cab-mounted boil-off pipe and the chassis-mounted liquefied gas fuel tank may, when the cab is moved from a tilted to a non-tilted position, easily and automatically be brought into a position in which gas evaporated from the tank is evacuated through the boil-off pipe. The solution with the downwardly open bottle configuration as a lower end connection of the boil-off pipe configured to receive a tank pipe member makes it easy to design the size of the bottom opening of the bottle configuration sufficiently large for allowing the tank pipe member to be introduced into the lower opening of the bottle configuration independent of certain movement of the cab and thus bottle configuration relative to the chassis and thus tank pipe member and certain movement of the introduction portion of the tank pipe member relative to the bottle configuration. By thus providing a downwardly open bottle configuration as a lower end connection of the boil-off pipe adapted to receive the tank pipe member, contact between bottle configuration and tank pipe member may be avoided, which reduces risk of fatigue and wear in connection to cab movements in the non-tilted position of the cab. Hereby a relatively simple and cost efficient design for facilitating evacuating evaporated liquefied gas of a liquefied gas fuel system of a vehicle from the chassis-mounted liquefied gas fuel tank through the cab-mounted boil-off pipe.

According to an embodiment of the arrangement the bottle configuration and the tank pipe member are configured so that, in the non-tilted position, during cab and thus bottle configuration movement, the bottle configuration is allowed to move freely relative to the portion of the tank pipe member positioned in the bottle configuration.

According to an embodiment of the arrangement the portion of the tank pipe member, when positioned in the bottle configuration, is positioned so that there is no contact between the portion of the tank pipe member and the bottle configuration, irrespective of cab movements. Hereby the risk of fatigue and wear in connection to cab movements in the non-tilted position of the cab may be reduced. According to an embodiment of the arrangement the bottle configuration has an upper tapered portion. Hereby evacuation of gas from the tank pipe member to the boil-off pipe is facilitated.

According to an embodiment of the arrangement the bottle configuration has a lower cylindrical portion. Hereby contact of the portion of the tank pipe member introduced into the bottle configuration may be efficiently avoided independent of movement of the bottle configuration relative to the portion of the tank pipe member introduced into the bottle configuration.

Specifically an object of the invention is achieved by a vehicle comprising an arrangement as set out herein.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present disclosure reference is made to the following detailed description when read in conjunction with the accompanying drawings, wherein like reference characters refer to like parts throughout the several views, and in which:

Fig. 1 a schematically illustrates a side view of a vehicle with a tiltable cab in a non-tilted position, the vehicle having an arrangement for facilitating evacuating evaporated liquefied gas of a liquefied gas fuel system of a vehicle according to an embodiment of the present disclosure;

Fig. 1 b schematically illustrates a side view of the vehicle in fig. 1 a with the cab in a tilted position;

Fig. 2 schematically illustrates a perspective view of boil-off pipe and tank pipe member of the liquefied gas fuel system and the arrangement for facilitating evacuating evaporated liquefied gas of the liquefied gas fuel system for a non- tilted position according to an embodiment of the present disclosure;

Fig. 3 schematically illustrates a side view of the arrangement in fig. 1 a with a bottle configuration and a portion of the tank pipe member introduced into the bottle configuration according to an embodiment of the present disclosure; and Fig. 4 schematically illustrates a perspective view of the bottle configuration of the arrangement in fig. 1 a according of an embodiment of the present disclosure.

DETAILED DESCRIPTION

Hereinafter the term“liquefied gas” refers to liquefied natural gas, LNG, or liquefied biogas, LBG.

Hereinafter the term“liquefied gas fuel system” refers to a fuel system for liquefied natural gas, LNG, or a fuel system for liquefied biogas, LBG. Hereinafter the term“flexible hose” refers to hoses configured to transport fluid for a liquefied gas fuel system, the hose being bendable to a certain degree and having a certain flexibility so as to facilitate taking up relative movements of a vehicle cab relative to a liquefied gas fuel tank.

Hereinafter the term“boil-off pipe” refers to a pipe, preferably a rigid pipe, configured to evacuate evaporated gas from a liquefied gas fuel tank of a liquefied gas fuel system. The pipe is according to an embodiment made of stainless steel. The boil-off pipe could alternatively be flexible such as a flexible hose. The boil-off pipe may have any suitable cross section comprising circular cross section or other polygonal cross section such as e.g. square cross section.

Hereinafter the term“tank pipe member” refers to any suitable pipe or hose or a combination thereof. The tank pipe member may have any suitable cross section comprising circular cross section or other polygonal cross section such as e.g. square cross section. Fig. 1 a schematically illustrates a side view of a vehicle 1 with a tiltable cab 2 in a non-tilted position; and fig. 1 b schematically illustrates a side view of the vehicle 1 in fig. 1 a with the cab 2 in a tilted position. The vehicle has an arrangement A for facilitating evacuating evaporated liquefied gas of a liquefied gas fuel system I of a vehicle according to an embodiment of the present disclosure.

The vehicle 1 has a vehicle chassis 3. The cab 2 is tiltable relative to the vehicle chassis 3. The cab 2 is movably connected to the vehicle chassis in a non- tilted position of the cab 2.

The exemplified vehicle 1 is a heavy vehicle in the shape of a truck. The vehicle 1 is fuelled by means of the liquefied gas fuel system I for operating the engine of the vehicle. The vehicle 1 may be any suitable truck configured to be arranged with a load carrying part behind the cab 2. Such a vehicle may be a truck arranged to carry an overhang behind the cab 2 or a semi-trailer truck comprising a towing truck and a semi-trailer coupled to the towing truck behind the cab 2 via a fifth wheel.

The cab 2 is tiltable between a non-tilted position, illustrated in fig. 1 a, in which the cab is upright and the vehicle may be driven, and a tilted position, illustrated in fig. 1 b. In the non-tilted position, the cab 2 is locked by means of a cab locking arrangement comprising cab locking members, not shown. A locking arrangement is thus provided having a cab locking portion of the cab 2 and a chassis locking portion of the chassis 3 for locking the cab to the chassis in the non-tilted position of the cab. The cab locking portion is connected to a cab body of the cab via a spring configuration for allowing movement of the cab body relative to the cab locking portion, not shown here.

The cab 2 may be tilted in any suitable way by any tiltable means. The cab 2 is according to an embodiment tiltable by means of a cab tilting operation arrangement 50 shown in fig. 1 a. The cab tilting operation arrangement 50 comprises a pump unit 52 and at least one hydraulic piston unit 54 for tilting the cab 2, hydraulically connected to the pump unit 52 via a hydraulic line. The vehicle thus comprises a liquefied gas fuel system I. The liquefied gas fuel system I comprises a chassis-mounted liquefied gas fuel tank 10 for providing fuel to the engine of the vehicle 1.

The liquefied gas fuel system I comprises a boil-off pipe 20 through which evaporated gas from the tank 10 is configured to be evacuated at a certain tank pressure. The boil-off pipe 20 is configured to be connected to the fuel tank 10. The liquefied gas fuel system I for liquefied gas is provided with a relief valve, not shown, which is set to open at the certain pressure for evacuating evaporated gas from the tank 10 via the boil-off pipe 20. The pressure may be any suitable pressure. The pressure is according to an embodiment about 16 bar. The pressure may depend on the size of the tank.

The vehicle 1 illustrated in fig. 1 a-b is a simplified illustration. The vehicle chassis of the vehicle 1 normally comprises a vehicle frame comprising a left longitudinal vehicle beam and a right longitudinal vehicle beam, not shown. The liquefied gas fuel tank 10 is arranged in connection to the vehicle frame. The liquefied gas fuel tank 10 may according to an embodiment comprise a left liquefied gas fuel tank part arranged in connection to a left longitudinal vehicle beam and a right liquefied gas fuel tank part arranged in connection to the right longitudinal beam of the chassis of the vehicle 1. The boil-off pipe 20 is attached to the rear side 2a of the cab 2. The boil-off pipe 20 is arranged to be fixedly attached to the rear side of the cab 2 by means of any suitable fastening means, e.g. any suitable joints such as one or more screw joints, see fig. 2. The boil-off pipe 20 is thus arranged to be tilted together with the cab 2 when the cab 2 is tilted to the tilted position. The boil-off pipe 20 has an upper side 20a with an opening through which the evaporated gas is arranged to be evacuated and an opposing lower side for receiving evaporated gas from the tank 10. The vehicle 1 comprises an arrangement A for facilitating evacuating evaporated liquefied gas of the liquefied gas fuel system I of the vehicle 1. The boil-off pipe 20 is configured to be attached to the rear side of the cab 2.

The arrangement A is configured to allow evaporated gas from the tank 10 to be evacuated through the boil-off pipe 20 in the non-tilted position of the vehicle 1.

The arrangement A comprises a downwardly open bottle configuration 30 as a lower end connection of the boil-off pipe 20.

The bottle configuration 30 together with the boil-off pipe 20 is thus arranged to be tilted together with the cab 2 when the cab 2 is tilted to the tilted position. The downwardly open bottle configuration 30 as a lower end connection of the boil-off pipe 20 is thus arranged to move together with any cab movement comprising movement between tilted and non-tilted positon of the cab 2 and movements of the cab 2 relative to the chassis 3 in the non-tilted positon of the cab 2.

According to an embodiment the bottle configuration 30 is attached to an end portion of the boil-off pipe 20. The end portion of the boil-off pipe 20 constituting the lower end portion of the boil-off pipe 20 when the boil-off pipe 20 is mounted to the rear side of the cab 2. Thus, in that embodiment the bottle configuration 30 constitutes a separate part configured to be attached to the lower end portion of the boil-off pipe 20.

According to an alternative embodiment the bottle configuration 30 constitutes an integrated portion of the boil-off pipe 20. Thus, in that embodiment the bottle configuration constitutes a lower end portion of the boil-off pipe 20, when the boil-off pipe is mounted to the rear side of the cab 2.

The arrangement A further comprises a tank pipe member 40 attached to the tank 10 for conveying evaporated gas from the tank 10. The tank pipe member 40 may be connected to the tank 10 in any suitable way. The tank pipe member may be any suitable pipe or hose or a combination thereof. The tank pipe member 40 may be connected to the chassis 1 of the vehicle 1 , see fig. 2. At least a portion of the tank pipe member 40 comprising the portion 42 has a certain rigidity so as to prevent or at least reduce/minimize movement of the portion 42. Thus, the portion 42 of the tank pipe member has a certain stiffness.

The bottle configuration 30 and the tank pipe member 40 are configured so that, when the cab 2 is moved from the tilted position, illustrated in fig. 1 b, to the non-tilted position, illustrated in fig. 1 a, a portion 42 of the tank pipe member 40 is introduced into the bottle configuration 30 through its lower opening 32 and positioned in the bottle configuration 30 so that gas evaporated from the tank 10 is introduced into the bottle configuration 30 via the tank pipe member 40 and evacuated through the boil-off pipe 20.

According to an embodiment of the arrangement A the bottle configuration 30 and the tank pipe member 40 are configured so that, in the non-tilted position, illustrated in fig. 1 a, during cab and thus bottle configuration movement, the bottle configuration 30 is allowed to move freely relative to the portion 42 of the tank pipe member 40 positioned in the bottle configuration 30. The bottle configuration 30 is thus allowed to move freely relative to the portion 42 of the tank pipe member 40 positioned in the bottle configuration 30 in all horizontal direction and vertical direction and combinations thereof. The bottle configuration 30 and also the tank pipe member 40, or at least the portion 42 of the tank pipe member 40 configured to be positioned in the bottle configuration 30, are thus dimensioned so that the is thus allowed to move freely relative to the portion 42 of the tank pipe member 40 positioned in the bottle configuration 30.

According to an embodiment of the arrangement A the portion 42 of the tank pipe member 40, when positioned in the bottle configuration 30, i.e. the inner space of the bottle configuration 30, is positioned so that there is no contact between the portion 42 of the tank pipe member 40 and the bottle configuration 30, irrespective of cab 2 movements. According to an embodiment of the arrangement the bottle configuration has an upper tapered portion.

According to an embodiment of the arrangement the bottle configuration has a lower cylindrical portion. Fig. 2 schematically illustrates a perspective view of a boil-off pipe 20 and tank pipe member 40 of the liquefied gas fuel system and the arrangement A for facilitating evacuating evaporated liquefied gas of the liquefied gas fuel system for a non-tilted position according to an embodiment of the present disclosure.

As illustrated in fig. 1 a-b, the boil-off pipe 20 is configured to be attached to the rear side of the cab of the vehicle, not shown here. The boil-off pipe 20 is arranged to be fixedly attached to the rear side of the cab by means of any suitable fastening means. According to this embodiment the fastening means comprises an upper fastening arrangement F1 , an intermediate fastening arrangement F2 and a lower fastening arrangement F3. The upper fastening arrangement F1 is configured to provide an attachment of the boil-off pipe 20 to the rear side of the cab in connection to an upper portion of the boil-off pipe 20. The intermediate fastening arrangement F2 is configured to provide an attachment of the boil-off pipe 20 to the rear side of the cab in connection to an intermediate portion of the boil-off pipe 20. The lower fastening arrangement F3 is configured to provide an attachment of the boil-off pipe 20 to the rear side of the cab in connection to a lower portion of the boil-off pipe 20.

The boil-off pipe 20 has an upper side 20a with an opening through which the evaporated gas is arranged to be evacuated and an opposing lower side for receiving evaporated gas from the tank via the tank pipe member 40.

The tank pipe member 40, i.e. the portion 42 of the tank pipe member has an upper end side 40a through which the evaporated gas is arranged to be evacuated into the bottle configuration 30 for evacuation through the boil-off pipe, when the portion 42 of the tank pipe member 40 has been introduced into the bottle configuration 30. The tank pipe member 40 has an opposing end 40b configured to be connected to the liquefied gas fuel tank.

As illustrated in fig. 2, the tank pipe member 40 is configured to be attached to the vehicle chassis, not shown here. The tank pipe member 40 is arranged to be fixedly attached to the vehicle chassis, directly or via any suitable member fixed to the vehicle chassis, by means of any suitable fastening means. According to this embodiment the fastening means comprises a tank pipe member fastening arrangement F4. The tank pipe member fastening arrangement F4 is configured to attach the tank pipe member 40 relatively close to the portion 42 of the tank pipe member 40 so as to minimize movement of the portion 42 of the tank pipe member 40. Flereby it is facilitated to keep the portion 42 of the tank pipe member 40 straight and directed such that it is securely introduced into the lower opening 32 of the bottle configuration 30 when the cab is moved from the tilted to the non-tilted position. Fig. 3 schematically illustrates a side view of the arrangement A in fig. 1 a with a bottle configuration 30 and a portion 42 of the tank pipe member 40 introduced into the bottle configuration 30 according to an embodiment of the present disclosure.

The portion 42 of the tank pipe member 40 has thus been introduced into the lower opening 32 of the bottle configuration 30.

According to this embodiment the bottle configuration 30 has an upper tapered portion 34 so as to facilitate evacuating of gas from the tank pipe member 40, i.e. the portion 42 of the tank pipe member 40, to the boil-off pipe.

According to this embodiment the bottle configuration 30 has a lower cylindrical portion 36 so as to facilitate avoiding contact of the portion 42 of the tank pipe member 40 introduced into the bottle configuration 30 independent of movement of the bottle configuration 30 relative to the portion 42 of the tank pipe member 40 introduced into the bottle configuration 40. The cylindrical portion 36 has a height H. The height FI of the cylindrical portion 36 of the bottle configuration 30 is dimensioned so as to secure that the portion 42 of the tank pipe member 40 remains in the cab-mounted bottle configuration 30 independent of cab and thus bottle configuration movements, e.g. vertical movements/movements in the longitudinal direction of the bottle configuration 30, relative to the portion 42 of chassis mounted tank pipe member 40. Thus, the length of the portion 42 of the tank pipe member 40 may vary due to such movements of the bottle configuration in the non-tilted position of the cab.

The cylindrical portion 36 has a diameter D1. The tank pipe member 40, i.e. the portion 42 of the tank pipe member 40 configured to be introduced into the lower opening 32 of the bottle configuration 30 has a diameter D2.

The diameter D1 of the cylindrical portion 36 of the bottle configuration 30 and diameter D2 of the portion 42 are dimensioned so that the size of the bottom opening 32 of the bottle configuration 30 is sufficiently large for allowing the portion 42 of the tank pipe member to be introduced into the lower opening 32 of the bottle configuration 30 independent of certain movement of the cab and thus bottle configuration 30 relative to the chassis and thus tank pipe member 40 and certain movement of the introduction portion 42 of the tank pipe member relative to the bottle configuration 30.

The diameter D1 of the cylindrical portion 36 of the bottle configuration 30 and diameter D2 of the portion 42 are dimensioned so that contact of the portion 42 of the tank pipe member 40 introduced into the bottle configuration may be efficiently avoided independent of movement of the bottle configuration 30 relative to the portion 42 of the tank pipe member 40 introduced into the bottle configuration 30. Fig. 4 schematically illustrates a perspective view of the bottle configuration 30 of the arrangement in fig. 1 a according of an embodiment of the present disclosure. The bottle configuration 30 according to this embodiment thus has a lower opening 32, an upper tapered portion 34 and a lower cylindrical portion 36. The cylindrical portion 36 has a height H and a diameter D1. The foregoing description of the preferred embodiments of the present disclosure has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated.