Abstract:
A system for providing dispensing of fuel for refuelling vehicles, comprising a control unit and at least two switches. Each of said switches is connected to the control unit and comprises a microcontroller for storing a unique identifier, which identifier is associated with the switch and readable by the control unit, for allowing the control unit to identify each of the at least two switches.

Description:
CLAIM OF PRIORITY 
       [0001]    Under 35 U.S.C. § 119, this application claims the benefit of a foreign priority application filed in the European Patent Convention, serial number 07108732.4, filed May 23, 2007, the entire contents of which are hereby incorporated by reference. 
       TECHNICAL FIELD 
       [0002]    The present invention relates to a system for providing dispensing of fuel, in particular a fuel dispensing unit and a fuel payment terminal, and various techniques for detecting specific events associated with the system. 
       BACKGROUND ART 
       [0003]    Different techniques are available on the market for detecting events occurring in connection with a fuel dispensing unit and/or a fuel payment terminal. Some events that should be detected are related to the operation of the fuel dispensing unit, such as detecting if a fuel dispensing nozzle is lifted from its nozzle boot, what kind of fuel grade is selected for dispensing etc. Other events are related to misuse of the dispenser, e.g. attempts to steal fuel. 
         [0004]    Today, switches that employ magnetic field sensors, push-buttons, etc. are used for detecting certain events. Moreover, it is known that fuel dispensers may incorporate nozzle detecting switches that are capable of performing logical operations. However, at present it is not clear what kind of logic such switches perform. 
         [0005]    A problem with switches for fuel dispensing units is that it is hard to use a more common switch design for detecting several different kinds of events, such as lifting a fuel dispensing nozzle, selecting a specific fuel grade, releasing a theft alarm, etc. 
         [0006]    In cases of burglary and other tampering for the purpose of stealing fuel, anti-theft systems are used which incorporate some kind of tamper-detecting sensor that breaks a switch which thus gives or breaks a signal between the fuel dispensing unit and a central unit. When this occurs contact is lost between the fuel dispensing unit and the central unit, an alarm is initiated and the fuel dispensing unit is inactivated. Inactivation involves, for instance, setting a logic variable in the control system of the pump at a certain value so that that pumping is not allowed, or, in a mechanical control system, activating a mechanical stop which physically prevents pumping. 
         [0007]    U.S. Pat. No. 6,067,476, for example, discloses a technique for protecting a fuel dispenser unit by detecting tampering with a totalizing device acting to keep a running total of fuel dispensed from the fuel dispenser. An electric circuit is included and contains a coil that emits a magnetic pulse that is responsive to a condition consistent with proper totalizer operation. Arrangements are included for sensing the presence of the magnetic pulse, generating a signal responsive thereto and causing an alarm responsive to absence of the magnetic pulse. 
         [0008]    A drawback of the above-described anti-theft systems is that they still can relatively easily be tampered with so as to allow theft of fuel. By existing components being bypassed, joined with tape, broken to pieces or replaced with other components, the fuel dispensing unit can be started so that theft of fuel can take place. 
       SUMMARY OF THE INVENTION 
       [0009]    A system for providing dispensing of fuel for refuelling vehicles is described, comprising a control unit and at least two switches. Each of said switches is connected to the control unit and comprises a microcontroller for storing a unique identifier, which identifier is associated with the switch and readable by the control unit, for allowing the control unit to identify each of the at least two switches. 
         [0010]    In one embodiment, each switch has an identifier, which facilitates the switch&#39;s communication with the control unit and provides for versatile operation of the switches and use of more standardized switches. Of course, each switch is configured to detect a certain event, e.g. selection of a specific fuel grade, tampering of the system etc. 
         [0011]    Each switch may comprise a power source, for allowing the switch to operate independently of the control unit and thereby, for example, provide for a more versatile and/or tamper-proof implementation of the switch, since the switch is no longer dependent on an external power source. 
         [0012]    Each switch may be configured to store a key which represents a condition where tampering of the fuel system is not detected, which provides a switch-status indicating, for example, that dispensing of fuel is allowed. This embodiment specifically addresses the aspect of tampering. 
         [0013]    The key may be altered when the switch is released, and the key may be altered when the connection between the switch and the control unit is lost, which presents a simple and efficient way of indicating that undesired events have taken place. 
         [0014]    The control unit may be configured to store a copy of each key, for the purpose of verifying if tampering of the system has occurred, and the control unit may be configured to regularly read the key for each switch, which provides a system that may continuously monitor its switches, which in turn renders tampering with the switches even harder. 
         [0015]    The control unit may be configured to regularly change the key for each switch, which makes tampering even harder. 
         [0016]    Each of the at least two switches may be connected to the control unit via a common communication line, which reduces the cost of manufacturing the fuel dispenser, as well as improves versatile use of the switches. 
         [0017]    According to another aspect of the invention, a fuel dispensing unit for refuelling vehicles is provided, which comprises a system according to any of the embodiments described above. 
         [0018]    The control unit may be arranged in a first subspace of the fuel dispensing unit and each of the at least two switches may be arranged in a second subspace of the fuel dispensing unit, for physically separating the switches from the control unit. 
         [0019]    The first subspace and the second subspace may be arranged for preventing fuel vapour from spreading between the subspaces, which allows the control unit to be powered with a relatively higher voltage. This provides for a more simple and cost efficient control unit for the switches while the risk of explosion is reduced. 
         [0020]    In the fuel dispensing unit, each of the switches may be connected to the control unit via a barrier device for explosion protection, said barrier device disposed between the switches and the control unit, which further reduces the risk of explosion. 
         [0021]    In the fuel dispensing unit, a sealing member may be arranged between the first subspace and the second subspace for close abutment against a communication line that connects each of the at least two switches to the control unit, which efficiently decreases the risk of explosion. 
         [0022]    In the fuel dispensing unit, a fuel flow meter may be connected to the communication line, and each of the switches may be connected to the control unit via the fuel flow meter, which provides for a fuel dispenser that allows more cost efficient implementation of the switches. 
         [0023]    The switches may be arranged for detecting a respective fuel dispensing nozzle, which provides a solution where the overall cost of implementing the switches is further reduced. 
         [0024]    According to yet another aspect of the invention, a fuel payment terminal for paying for fuel is provided, which comprises a system according any of the embodiments described above. 
         [0025]    It should be noted that the “identifier” described above may represent the “key”, or vice versa. 
         [0026]    Moreover, a “microcontroller” is an electronic circuit that comprises a memory, an input/output interface and a capability of performing at least one logic operation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    Embodiments of the present invention will now be described, by way of example, with reference to the accompanying schematic drawings, in which 
           [0028]      FIG. 1  is a schematic view of the inventive system incorporated in a fuel dispensing unit, 
           [0029]      FIG. 2  is a schematic view of a switch according to the invention, and 
           [0030]      FIG. 3  is a schematic view of the inventive system incorporated in a fuel payment terminal. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0031]      FIG. 1  illustrates one embodiment of a fuel dispensing unit  1  that incorporates the system and which is divided into a first subspace  2  and a second subspace  3 . Both subspaces  2 ,  3  are indicated by dashed lines. In the second subspace  3  a fuel line  6  is arranged for drawing fuel from a fuel reservoir  4 . The fuel line  6  comprises a fuel pump  5  for generating a stream of fuel, which is divided into two separates streams, each entering a respective fuel meter  7 ,  8 . The first fuel meter  7  is connected downstream to a first fuel line  9  to which a first, flexible fuel hose  10  is connected. The first fuel hose  10  has a fuel dispensing nozzle  11  for dispensing fuel into a tank of a vehicle (not shown). 
         [0032]    The second fuel meter  8  is connected downstream to a second fuel line  13  to which a second, flexible fuel hose  14  is connected, which in turn has a fuel dispensing nozzle  15  to corresponding the nozzle  11  of the first fuel hose  10 . When the fuel dispenser  1  is not operated, each of the nozzles  11 ,  15  rest in a respective nozzle boot  12 ,  16  arranged on the side of the fuel dispenser  1 . 
         [0033]    Preferably, each fuel meter  7 ,  8  has a unique identifier corresponding to the identifiers of the switches described blow. 
         [0034]    In the first subspace  2 , a control unit  19  is arranged for controlling the operation of the fuel dispenser  1 . The control unit  19  is connected to the fuel meters  7 ,  8  via a communication line  18  and receives from the fuel meters  7 ,  8  signals representative of an amount of fuel dispensed at the fuel dispensing nozzles  11 ,  15 . The control unit  19  has a conventional, suitable processor  20  and a memory  21 . 
         [0035]    Since certain electric voltages are present in the control unit  19 , the communication line  18 , as shown, includes an EExi barrier device  23  which is arranged between the control unit  19  and fuel meters  7 ,  8  in order to provide explosion protection for flammable fuel present in, for example, the fuel meters  7 ,  8 . The EExi barrier device  23  is preferably an electronic device having a protective function in potentially explosive atmospheres, and its technical requirements are stipulated in Directive 94/9/EC (ATEX). The EExi barrier device  23  may also be a barrier device according to CENELEC standards, or according to any other suitable standard for providing the required protection. Instead of an EExi barrier device  23 , an EExd, EExp, EExn or EExm barrier device may be used, or any other device providing similar functionality. In brief, the barrier device  23  is intrinsically safe by ensuring that electric current and voltage levels are reduced in the electric components that are arranged in the second subspace  3 , where fuel vapour is more common. 
         [0036]    The first subspace  2  is sealed from the second subspace  3  by means of a boxlike structure (not shown) made of steel or plastic and encloses the control unit  19  and thereby prevents fuel vapour from spreading from the second subspace  3  to the first subspace  2 . Preferably, a sealing member  22  is arranged between the first subspace  2  and the second subspace  3 . The sealing member  22  comprises two flexible members that abut closely against the communication line  18  and thereby provide a vapour tight cable penetration between the subspaces  2 ,  3 . 
         [0037]    Optionally, spreading of fuel vapour between the subspaces  2 ,  3  is prevented by the first subspace  2  and the second subspace  3  being arranged at a specific, minimum distance from each other. 
         [0038]    Two switches  25 ,  26  are arranged in the second subspace  3  for detecting events indicative of misuse of the fuel dispensing unit  1 . The switches  25 ,  26  detect in a conventional manner, for example, opening of a front panel (not shown), vibrations and impacts on the fuel dispensing unit, a sound having a frequency corresponding to a frequency generated when drilling through a front panel of the fuel dispensing unit  1 , or any other event indicative of misuse of the fuel dispensing unit  1 . 
         [0039]    As shown, each switch  25 ,  26  is connected to the control unit via the communication line  18  which is common for the two switches  25 ,  26 . This means that signals between the control unit  19  and each switch  25 ,  26  pass along the same wire in the communication line  18 . 
         [0040]    The communication line  18  may, of course, have multiple wires, but signals from both switches  25 ,  26  are typically sent to the control unit  19  via a common wire of the multiple wires. 
         [0041]    Moreover, a first nozzle detecting switch  27  is arranged at the first nozzle boot  12 , while a second nozzle detecting switch  28  is arranged at the second nozzle boot  16 . Each nozzle detecting switch  27 ,  28  has a magnetic sensor that detects a magnetic field generated by a magnet (not shown) arranged in the respective fuel dispensing nozzle  11 ,  15 , when respective fuel dispensing nozzle  11 ,  15  is properly placed in its nozzle boot  12 ,  16 . Both nozzle detecting switches  27 ,  28  are connected to the control unit  19 , via the communication line  18  which, as shown, is common also for the two switches  27 ,  28 , in a manner that corresponds to the connection of the previously discussed tamper-detecting switches  25 ,  26 . 
         [0042]    The switches  25 ,  26 ,  27 ,  28  discussed above are illustrated by the generic switch  30  illustrated in  FIG. 2 . The switch  30 , as shown, has a conventional, suitable microcontroller  31  which comprises a central processing unit  36 , a combined RAM and ROM memory unit  32 , input/output interfaces and a clock generator (not shown). 
         [0043]    The switch  30 , as shown, also includes a battery  33  and a connector  34 , which both are connected to the microcontroller  31 . The connector  34  is arranged for connecting the switch  30  to the communication line  18 . The switch  30  also incorporates a sensor  35  which communicates with the microcontroller  31 . Depending on the field of application for the switch  30 , the sensor  35  is configured to detect a specific sound, a magnetic field, vibrations etc. The components of the switch  30  cooperate in a conventional manner, and the earlier described switches  25 ,  26 ,  27 ,  28  are typically, except for the sensor  35  that depends on the particular application area for each switch  25 ,  26 ,  27 ,  28 , structurally identical with the switch  30  of  FIG. 2 . 
         [0044]    Each of the switches  25 ,  26 ,  27 ,  28  are during normal operation powered by the control unit  19  via the communication line  18 , but if the connection with the control unit  19  is lost, the switch may be powered by its battery  33 . However, since the nozzle detecting switches  27 ,  28  are not arranged for detecting misuse of the fuel dispenser  1 , backup power is not crucial for the nozzle detecting switches  27 ,  28  and hence their batteries may be omitted. 
         [0045]    In the memory  32  of each switch  25 ,  26 ,  27 ,  28  a unique identifier is stored, i.e. each switch  25 ,  26 ,  27 ,  28  has a unique identifier, and in the memory  21  of the control unit  19  each unique identifier is stored. During communication over the communication line  18  each signal to and from the switches  25 ,  26 ,  27 ,  28  incorporates such a unique identifier, and each switch  25 ,  26 ,  27 ,  28  is in a conventional manner arranged to respond only to signals involving its unique identifier. In a corresponding manner signals from the switches  25 ,  26 ,  27 ,  28  incorporate its unique identifier, which enables the control unit  19  to, in a conventional manner, identify from which switch  25 ,  26 ,  27 ,  28  the signal is sent. Of course, in this context a “signal” means a data package or signal package. 
         [0046]    In the communication line  18  data is carried in bit-serial form, and any suitable serial bus specification may be employed for the connection and communication between the control unit  19  and the switches  25 ,  26 ,  27 ,  28 , such as, for example, the CAN-specification. 
         [0047]    Each of the tamper-detecting switches  25 ,  26  has a key stored in its memory  32 , which key is also stored in the control unit  19 . The control unit  19  repeatedly, e.g. once every 30 seconds, interrogates each tamper-detecting switch  25 ,  26  for its key, and as long as a correct key is received, operation of the fuel dispensing unit  1  is allowed. However, when a tamper-detecting switch  25 ,  26  indicates detection of the event that it is configured to detect, the key is deleted from its memory  22 , preferably by the switch itself. This means that the control unit  19  will not longer receive a correct key, which is interpreted by the control unit  19  as misuse of the fuel dispensing unit  1  and which triggers a suitable alarm, such as a warning signal in a manned petrol station. If the connection between a tamper-detecting switch  25 ,  26  and the control unit  19  is lost, the control unit  19  receives no answer at all from the switch  25 ,  26 , which also triggers the alarm. 
         [0048]    After a tamper-detecting switch  25 ,  26  is released and is reset by maintenance personnel, the control unit  19  sends a new key to the released switch  25 ,  26 . 
         [0049]    The communication line  18  may also be a wireless communication line, in which case any suitable radio-frequency means are incorporated in the fuel dispenser. 
         [0050]      FIG. 3  illustrates a fuel payment terminal  37  that incorporates the system. The fuel payment terminal  37  has a control unit  19  corresponding to the control unit of the fuel dispenser and to which a display  38 , a keyboard  39  and a credit/payment card unit  40  is connected. The control unit  19  has a processor  20  and a memory  21 , and three tamper detecting switches  24 ,  25 ,  26  are connected to the control unit  19  via one, common communication line  18 . 
         [0051]    The switches  24 ,  25 ,  26  are configured to detect misuse and cooperate with the control unit  19  via the communication line  18  in a manner corresponding to the control unit, communication line and tamper detecting switches of the fuel dispensing unit described above.