Patent Publication Number: US-6990945-B1

Title: Vehicle fueling arrangement

Description:
TECHNICAL FIELD 
     The present invention generally relates to vehicle fueling safety, and more particularly relates to inhibiting engine operation during fueling. 
     BACKGROUND 
     Most vehicle fueling stations request that engines be turned off during fueling to avoid a risk of fire or explosion due to engine operation igniting fuel vapors associated with the fueling process. This is particularly important when fueling with gasoline. This is a voluntary process that depends upon user cooperation or perhaps station attendant enforcement. However, many fueling stations are now self-service and customers often leave their engines running, especially in cold weather. Thus, there is a need for a system that would insure that engines are automatically disabled during fueling. 
     Accordingly, it is desirable to provide an apparatus and method that disables the engine when fueling or when fueling is about to take place. In addition, it is desirable that the apparatus and method be automatic so that the engine is disabled during fueling without user action. In addition, it is desirable that the fueling safety system automatically reset when fueling is complete so that the engine can once again be started. Other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background. 
     BRIEF SUMMARY 
     An apparatus is provided for limiting vehicle engine operation during fueling. In a first embodiment, the apparatus comprises, an engine control for enabling or disabling operation of the engine and one or more sensors for detecting whether: (i) a cap is on the vehicle fuel fill-pipe, and (ii) an external fuel supply nozzle is inserted in the vehicle fuel fill-pipe. A processor is provided coupled to the engine control and the sensors. The processor receives information from the sensors and directs the engine control to automatically enable or disable the vehicle engine depending upon the sensor outputs. The engine is disabled when the cap is not on the vehicle fuel fill-pipe, and enabled when the cap is on the fuel fill-pipe. An emergency by-pass switch is desirably included that makes the system insensitive to outcome (i). Under outcome (ii) the vehicle engine is disabled when the external fuel supply nozzle is in the vehicle fill-pipe and enabled when not in the fill-pipe. In a further embodiment that does not require the cap and nozzle sensors, there is provided a fuel level sensor coupled to the processor and an engine idle timer coupled to the engine controller. The engine is shut off if the fuel level changes by a predetermined amount or more. An engine idle timer is preferably used in conjunction with the fuel level sensor. 
     A method is provided for limiting vehicle engine operation during fueling. In a first embodiment, the method comprises testing whether a fuel-cap by-pass switch is ON (YES) or OFF (NO), and if OFF (NO), determining if the fuel-cap is OFF the fuel fill-pipe of the vehicle. If the fuel fill-pipe cap is ON the fuel fill-pipe, enabling operation of the engine of the vehicle, and if the cap is OFF, disabling operation of the vehicle engine. If the fuel cap by-pass switch is ON (YES), then determining if a fuel supply nozzle is in the fuel fill-pipe of the vehicle, and if YES, disabling operation of the vehicle and if NO, enabling operation of the vehicle. Except for the by-pass switch, the process is automatic and does not require operator intervention. In a further embodiment the cap and nozzle sensors are not needed, but a fuel level sensor and, optionally an engine idle timer, are used to determine the fueling state and engine operating duration. The engine is shut off if the fuel level changes by a predetermined amount or more. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and 
         FIGS. 1A–1C  are simplified partially cut-away and cross-sectional views of a fuel fill-pipe region of a vehicle according to the present invention for three fueling situations; 
         FIGS. 2A–D  show enlarged portions of the fuel fill-pipe arrangement of  FIGS. 1B–1C  providing further details according to several embodiments of the present invention; 
         FIG. 3  is a simplified electrical schematic block diagram of the control system of the present invention for disabling the vehicle engine during fueling; 
         FIG. 4  is a simplified flow chart of the method of the present invention according to a first embodiment; and 
         FIG. 5  is a simplified flow chart of the method of the present invention according to further embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. 
       FIGS. 1A–1C  are simplified partially cut-away and cross-sectional views of fuel fill-pipe region  10  of a vehicle according to the present invention for three fueling situations  10 - 1 ,  10 - 2 ,  10 - 3 . Fuel fill-pipe region  10  comprises vehicle body portion  12  having optionally recessed fill-pipe access region  14 . Fuel fill-pipe  16  has end region  18  that protrudes into optional access region  14 . While fill-pipe access region  14  is desirably recessed to protect end region  18  of fill-pipe  16  from knocks and bumps, this is not essential and end region  18  of fill-pipe  16  may protrude directly from vehicle body  12  without recess  14 . End region  18  of fill-pipe  16  has opening  22  with threaded region  20  into which fuel fill-pipe cap  24  may be screwed or otherwise installed to contain fuel vapors within the fuel tank. The use of threads  22  for fuel fill-pipe cap  24  is convenient but not essential and the placement of the threads is not critical. Any means of closing opening  22  of end region  18  of fuel fill-pipe  16  may be used. 
     Fuel fill-pipe situation  10 - 1  of  FIG. 1A  shows fuel fill-pipe  16  with opening  22  closed by fuel fill-pipe cap  24 . In this case it is assumed that cap  24  screws into threads  20  of fuel fill-pipe  16 , but this is not essential. Any means of attaching cap  24  to fuel fill-pipe  16  may be used. Cap  24  blocks opening  22  so that no significant fuel vapors can escape from the vehicle fuel tank (not shown). Fuel fill-pipe situation  10 - 2  of  FIG. 1B  shows the same fuel fill-pipe but with fuel fill-pipe cap  24  removed. Fuel fill-pipe situation  10 - 3  shown in  FIG. 1C  shows fuel fill-pipe  16  with cap  24  removed and fueling apparatus  26  having fueling nozzle  30  inserted in opening  22  of fuel fill-pipe  16 . Fueling apparatus  26  has ON/OFF trigger  28  and fueling nozzle  30 . Nozzle  30  penetrates opening  22  into end region  18  of fuel fill-pipe  16 . Fuel  32  is delivered by fueling nozzle  30  into fuel fill-pipe  16  whence it runs into the vehicle fuel tank (not shown) as indicated by arrow  17 . Adjacent end region  18  of fuel fill-pipe  16  is cap sensor  36  and nozzle sensor  38 . Cap sensor  36  senses when cap  24  is mounted on fuel fill-pipe  16  and nozzle sensor  38  senses when fueling nozzle  30  is inserted into fuel fill-pipe  16 . Further details of sensors  36 ,  38  are illustrated in  FIGS. 2A–C . For convenience of illustration, sensors  36 ,  38  are shown as being mounted on end region  18  but this is not essential. 
       FIGS. 2A–D  show enlarged end portions  18 - 1 ,  18 - 2 ,  18 - 3 ,  184  of end region  18  of fuel filler pipe  16  of  FIGS. 1A–1C , providing further details according to several embodiments of the present invention. The threaded portion of cap  24  by which it couples to threads  20  of fill-pipe  16  is omitted in  FIGS. 2A–D  for convenience of illustration.  FIGS. 2A–D  differ in how cap sensor  36  and nozzle sensor  38  are implemented. While different embodiments are shown in  FIGS. 2A–D , these are not intended to be limiting but merely to illustrate several ways in which the presence and absence of cap  24  and fueling nozzle  30  can be detected by cap sensor  36  and nozzle sensor  38  or combo sensor  368 . Persons of skill in the art will appreciate based on the description herein, that many other types and arrangements of sensors may also be used for detecting cap  24  and fueling nozzle  30  besides those illustrated and it is intended to incorporate these alternatives in the claims that follow. What is important for the present invention is that sensors  36 ,  38 ,  368 , detect the presence and absence of cap  24  and fueling nozzle  30 . 
     Referring now to  FIG. 2A  showing end region  18 - 1 , sensors  36 - 1 ,  38 - 1  are electromagnetic sensors using electromagnetic radiation and/or induction to detect the presence of cap  24  and fueling nozzle  30 . For convenience of illustration, only portion  24 - 1  of cap  24  is shown in  FIG. 1A . Electrical leads  37 - 1 ,  39 - 1  are coupled to sensors  36 - 1 ,  38 - 1  respectively. Mounted within portion  24 - 1  of cap  24  is region  40 . As cap  24  moves toward or away from outer end  44  of fill-pipe  16  as shown by arrows  42 , its presence or absence is detected by coil  36 - 1 . This may occur in several ways. For example and not intended to be limiting, where region  40  is metallic, the AC impedance of sensor coil  36 - 1  changes as region  40  approaches sensor coil  36 - 1 . Region  40  may be merely conductive or also magnetic and is preferably but not essentially annular in shape, but this is not essential. A ferro-magnetic or conductive region  40  will cause the AC impedance of sensor coil  36 - 1  to change as cap  24  is applied or removed from region  18 - 1  of fuel fill-pipe  16 . Alternatively, sensor  36 - 1  can operate as a radio frequency identification tag (RFID) sensor and region  40  can be an embedded microchip RFID tag. Such devices are well known in the art. In  FIG. 1A , sensor  38 - 1  for detecting fueling nozzle  30  as it moves in and out of opening  22  as shown by arrow  31  is depicted as being a coil type sensor utilizing electromagnetic radiation and/or induction to detect nozzle  30  by, for example, a change in impedance of sensor coil  38 - 1 . With this arrangement, end region  18 - 1  is desirably non-metallic or at least not highly conductive to facilitate the electromagnetic radiation and/or induction penetrating to nozzle  30 . 
     Referring now to  FIG. 2B , showing end region  18 - 2 , sensor  36 - 2  detects cap  24  as portion  24 - 2 , moving as shown by arrows  42 , approaches, impacts or depresses switch button or proximity detector  46  on sensor  36 - 2 . For convenience of explanation, only portion  24 - 2  of cap  24  is shown in  FIG. 2B . The status of switch or proximity detector  46  is read via leads  36 - 2 . Sensor  38 - 2  is an electromagnetic sensor using electromagnetic radiation and/or induction to detect the presence of fueling nozzle  30 . Electrical leads  39 - 2  are coupled to sensor  38 - 2 . In the implementation of  FIG. 2B , sensor coil  38 - 2  is desirably mounted inside end region  18 - 2  of fill-pipe  16  so as to be in closer proximity to nozzle  30 . The AC impedance of sensor coil  38 - 2  changes as nozzle  30  moves into or out of fill-pipe  16  as shown by arrows  31 . Nozzle  30  is usually made from a highly conductive non-sparking metal such as aluminum. The frequency of operation of sensor coil  38 - 2  is desirably selected to provide a significant change in coil impedance as fueling nozzle  30  is inserted and removed from fill-pipe  16 . 
     Referring now to  FIG. 2C  showing end region  18 - 3 , sensors  36 - 3 ,  38 - 3  are optical or acoustical sensors using optical or acoustic radiation to detect the presence of cap  24  and fueling nozzle  30 . For convenience of illustration, only portion  24 - 3  of cap  24  is shown in  FIG. 2C . Electrical leads  37 - 3 ,  39 - 3  are coupled to sensors  36 - 3 ,  38 - 3  respectively. Sensor  36 - 3  has emitter  50  and receiver  52 , although they may be combined. Emitter  50  sends out optical or acoustic signal  54  that is reflected off face  45  of cap portion  24 - 3  as it approaches end  44  of fill-pipe  16 , as shown by arrows  42 . By measuring the change in reflected signal  54 ′, the presence or absence of cap  24  is detected by sensor  36 - 3 . Sensor  38 - 3  desirably comprises optical or acoustic emitter  60  that emits signal  61  toward generally opposed receiver  62 . When fueling nozzle  30  is inserted in fill-pipe  16  to position  64 , it interrupts beam  61 , thereby causing receiver  62  to indicate that nozzle  30  is present in fill-pipe  16 . While sensor  38 - 3  is illustrated as being a transmission type sensor, this is merely for convenience of explanation and not intended to be limiting. Sensor  38 - 3  may also be a reflective type where transmitter  60  and receiver  62  are not mounted in opposed arrangement, but so that receiver  62  can register signals reflected from nozzle  30  and use the change in reflected signal as nozzle  30  is inserted or withdrawn to detect its presence. Either arrangement is useful. With the arrangement of  FIG. 2C , there is no limitation on the type of material used for fill-pipe  16 , nor does operation of the system depend upon the material used for fueling nozzle  30 . For example, nozzle  30  can be non-conductive and its presence will still be detected by sensor  38 - 3 . The arrangement of  FIGS. 2B and 2D  will also detect a non-conductive nozzle  30  provided that the frequency of operation of coil (or other radiator)  38 - 2 ,  368  is sufficiently high that the presence of a non-conductive nozzle  30  provides additional loading of coil  38 - 2 ,  368  through an increase in local dielectric constant or permeability caused by nozzle  30  being inserted in fill-pipe  16  and/or fuel  32  flowing into fill-pipe  16 . 
     While the implementations shown in  FIGS. 2A–C  have illustrated various types of sensors  36 ,  38  in combination, persons of skill in the art will understand that they need not be used merely in the pairings indicated in these figures but in various other combinations as well. For example, and not intended to be limiting, sensor  36 - 2  can be used in conjunction with sensor  38 - 3 , and so forth among the other possible combinations. Sensor  38 - 3  is mounted immediately adjacent end  44  of pipe  16 , which therefore gives an immediate response as nozzle  30 , is inserted into opening  22 . It will be appreciated by persons of skill in the art based on the description herein that sensors  38 - 1  and  38 - 1  can be similarly mounted adjacent end  44 . 
     While  FIGS. 2A–C  illustrate arrangements in which two separate sensors  36 ,  38  are used to sense cap  24  and nozzle  30 , this is not essential. Since fueling nozzle  30  cannot be inserted into fill-pipe  16  until after cap  24  is removed, it is possible to use a single sensor to detect both the removal of cap  24  and the insertion of fueling nozzle  30 . This arrangement is illustrated, for example, in  FIG. 2D  showing end region  18 - 4 . End region  18 - 4  has single coil-type sensor  368  mounted near end  44  of fill-pipe  16 , preferably surrounding opening  22 . In the upper half of  FIG. 2D , Cap  24 - 4  is shown for example as including annular shaped ring  41 , formed for example of ferrite. In the lower half of  FIG. 2D , cap  24 - 4 ′ is shown as having L-Shaped annular ring  41 ′. Many other shapes can also be used. The exact shape of region  41 ,  41 ′ is a compromise between space and cost versus using the shape that produces the largest difference in impedance viewed at leads  369  when cap  24  is attached or removed. Coil sensor  368  uses electromagnetic radiation and/or induction to detect when cap  24  is in place on fill-pipe  16  and when fueling nozzle  30  is present in fill-pipe  16 . Ring  41 ,  41 ′ and fueling nozzle  30  have different electromagnetic signatures and are never both present at the same time. Different AC impedances will be observed at leads  369  for the different possible situations: (i) cap on, no fueling nozzle; (ii) cap off, no fueling nozzle; or (iii) cap off, fueling nozzle present. Sensor coil  368  can also be part of a tuned circuit that is sensitive to not only the changes in inductance of sensor coil  368  in response to the presence or absence of cap  24  and pipe  30 , but also to changes in parasitic capacitance induced by cap  24  and/or pipe  30 . Either arrangement is useful. 
       FIG. 3  is a simplified electrical schematic block diagram of control system  70  of the present invention for disabling the vehicle engine during fueling. Control system  70  comprises processor  72 , fuel cap sensor  36  and fuel nozzle sensor  38  (or alternatively, combined sensor  368 ), user controls  74 , memory  76 , and engine control  78 . As will be more fully explained later, fuel level sensor  82  and engine idle timer  84  are also desirably provided but these are not essential for all embodiments of the present invention. Fuel cap sensor  36  is coupled to processor  72  by leads or bus  37  and fueling nozzle sensor  38  is coupled to processor  72  by leads or bus  39 . Alternative combined sensor  368  is coupled to processor  72  by leads or bus  369 . User controls  74  are coupled to processor  72  by leads or bus  75 , memory  76  is coupled to processor  72  by leads or bus  77 , and engine control  78  is coupled to processor  72  by bus or leads  73 . Engine control  78  is coupled to engine  80  by bus or leads  79 . In the discussion that follows it will be understood that combined sensor  368  may be substituted for fuel cap sensor  36  and fuel nozzle sensor  38 . Control system  70  governed by processor  72 , monitors the status of sensors  36 ,  38 ,  368  to determine when cap  24  is removed from fill-pipe  16  and fuel nozzle pipe  30  inserted. When it detects either of those events, it instructs engine control  78  to disable engine  80 , that is, if running shut it off and if not running, disable the engine start function. When processor  72  detects that fueling nozzle  30  has been removed and cap  24  restored on fill-pipe  16 , then it instructs engine control  78  to re-enable engine start so that the vehicle once again behaves normally. The foregoing occurs automatically without user input or action. Memory  76  is provided to retain programming steps such as are described in  FIG. 4  and temporary variables as needed to carry out the method of the present invention. 
     User controls  75  include at least an over-ride switch that disables the present invention in case of emergency in much the same way as over-ride switches are provided, for example, to disabling air-bag systems when a passenger might be harmed thereby. It is preferred that the disable switch be key-operated, much like most air-bag disable switches so that it is not accidentally set to the SYSTEM OFF position. A non-limiting example of when use of the over-ride switch might be needed is if cap  24  has been lost or stolen. Thus, activation of the appropriate user control should disable at least the fuel cap verification functions of the present invention. This can be done in various ways. For example and not intended to be limiting, by altering the signals received from sensor  36  so that they always indicate that fuel cap  24  is ON or changing the logical flow of method  100  of  FIG. 4  to default to a NO (FALSE) response to any FUEL CAP OFF ? queries or equivalent in method  100  of  FIG. 4 . This is explained more fully in connection with method  100  of  FIG. 4 . 
     Fuel level sensor  82  is coupled to processor  72  by leads or bus  83  and engine idle timer  84  is conveniently coupled to engine control  78  by bus or leads  85 . However, idle timer  84  may alternatively be a part of engine control  78  or be coupled to processor  72 . Either arrangement works. Most modern cars already have the equivalent of fuel level sensor  82  and the equivalent of engine timer  84  that provide data on fuel level and engine idle time to the on-board engine or power train management system. By monitoring the engine idle time and fuel level in the fuel tank, system  70  can determine with reasonable accuracy whether or not the vehicle is being fueled, and therefore disable engine  80  as discussed above. For example, if the fuel level in the fuel tank is increasing by at least amount R(t)=Rc per unit time where Rc is a predetermined threshold fueling rate parameter, then this is generally a positive indication that the vehicle is being fueled. If engine  80  is running it should be shut off and kept off as long as the fueling rate R(t) is at least Rc. It is also useful to monitor the engine idle time using timer  84 . Operation of system  70  utilizing fuel level sensor  82  and idle timer  84  will be more fully understood by reference to method  200  of  FIG. 5 . 
     Processor  72 , engine control  78 , memory  76  and idle timer  84  are shown as separate but interconnected elements in system  70  of  FIG. 3 , but this is merely for convenience of description and not intended to be limiting. The partitioning of functions among processor  72 , engine control  78 , memory  76  and idle timer  84  is a matter of design choice. Persons of skill in the art will understand that these functions may be combined in a single processor or controller or control processor or that engine or power train management systems already present in many vehicles can be used to provide these functions. What is important is that these functions be present in system  70  not that they have a particular architecture or implementation. Hence such variations are intended to be included in the claims that follow and the words “processor” or “controller” or “control processor” are intended to have this broader meaning and not be limited merely to the configuration shown in  FIG. 3 . 
       FIG. 4  is a simplified flow chart of method  100  of the present invention, according to a first embodiment. In  FIGS. 4–5 , the logical outcome YES (TRUE) is abbreviated as “Y” and the logical outcome NO (FALSE) is abbreviated as “N”. Method  100  begins with start  102  that desirably occurs on vehicle power-up, for example, when the key inserted in the ignition switch or the doors unlocked or other minimal vehicle function energized. It is preferable that START not depend upon the position of the ignition switch. Method  100  then proceeds to optional DISABLE SWITCH SET ? query  104  wherein it is determined whether or not the disable switch in user controls  74  has been activated. If the outcome of query  104  is YES (TRUE) indicating that the user has disabled the aspect of system  70  that checks for the presence of cap  24 , then method  100  proceeds to FUEL NOZZLE IN FILL PIPE ? query  106 . This is accomplished by processor  72  interrogating sensor  38  or  368  to determine whether fueling nozzle  30  is in fill-pipe  16 . If the outcome of query  106  is NO (FALSE) indicating that fueling nozzle  30  is not inserted in fuel fill-pipe  16 , then method  100  proceeds to ENABLE ENGINE step  108  wherein processor  72  directs engine control  78  to allow engine  80  to continue to run if running or to be started if not running. From ENABLE ENGINE step  108 , method  100  returns to start  102  and initial query  104  as shown by path  109 . Thus, when the disable switch has been SET, the vehicle engine will only be disabled if fueling nozzle  30  is present in fill-pipe  16 . Activating (i.e., SETTING) the disable switch in user controls  74  makes system  70  insensitive to the status of cap  24 . 
     If the outcome of query  106  is YES (TRUE) indicating that a fueling operation is either about to begin or is underway, then method  100  proceeds to DISABLE ENGINE step  112 . In step  112  if engine  80  is not running it is prevented from starting and, if engine  80  is running, it is shut off. This is accomplished by processor  72  sending appropriate commands to engine control  78 . 
     Returning now to query  104 , if the outcome of query  104  is NO (FALSE) indicating that the disable switch is not SET (i.e., not activated), then method  100  proceeds to FUEL CAP OFF ? query  110  wherein processor  72  determines by interrogating sensor  36  or  368  whether or not cap  24  is installed on fill-pipe  16 . If the outcome of query  110  is NO (FALSE) indicating that cap  24  is still on fill-pipe  16 , the method  100  advances to ENABLE ENGINE step  108  and proceeds as described earlier. If the outcome of query  110  is YES (TRUE) indicating that cap  24  has been removed from fill-pipe  16 , then method  100  proceeds to DISABLE ENGINE step  112  wherein, engine  80  is prevented from operating as long as fuel cap  24  is off of fill-pipe  16  (unless the disable switch is SET which bypasses this query). Following step  112  method  100  returns to start  102  and initial query  104  as shown by path  115 . As long as the system is energized it will cycle through method  100  and maintain the vehicle in an ENGINE-OFF condition if the fuel cap is off and the fueling safety by-pass switch is not SET, or even if the by-pass switch is SET, it will maintain the vehicle in an ENGINE-OFF condition as long as fueling nozzle  30  is in fill-pipe  16 . Thus, system  70  maintains the vehicle in a safer fueling state while accommodating foreseeable emergencies. While the forgoing description illustrates the use of both cap ON/OFF detection and fuel filling nozzle IN/OUT detection, this is not essential. Although using both sensors is preferred, fueling safety is also improved by using either one alone. Thus, the present invention also includes a system where either cap sensor  36  is provided or nozzle insertion sensor  38  is provided or both are provided, depending upon the needs of the designer. 
       FIG. 5  is a simplified flow chart of method  200  of the present invention according to a further embodiment of the present invention. Method  200  begins with start  202  that desirably occurs when the vehicle is started or the ignition left in the start or run position. Method  200  then proceeds to optional DISABLE SWITCH SET ? query  204  wherein it is determined whether a disable switch among user controls  74  has been activated. (This is analogous to step  104  of method  100 .) If this disable switch has been SET (query  204  yields YES (TRUE)), then method  200  returns to start  202  as shown by path  205  and the fueling safety features provided by system  70  and method  200  are not active. Use of query  204  and its associated disable switch is not essential but is desirable for those vehicles that may encounter very unusual circumstances. An example of such circumstances is with vehicles operating in extremely cold arctic weather where it is important to keep the engine operating even while fueling, or during military operations or other emergency situations, where the risk of engine or vehicle failure from the unusual conditions outweighs the increased hazard from engine operation during fueling. However, these are generally rare situations. 
     If the outcome of query  204  is NO (FALSE) indicating that the disable switch has not been SET, then method  200  proceeds to ENGINE IDILING ? (t(i)≧tc) ? query  206 . In query  206  it is determined whether or not the engine is running, e.g., idling. In the preferred embodiment, it is also determined whether or not the engine idle time t(i) equals or exceeds a predetermined idle time tc, but this is not essential. The parameter tc is preferably chosen to represent the typical time it takes a driver to exit the vehicle and begin fueling and is usefully in the range of about 5 to 50 seconds, more conveniently about 10 to 30 seconds and preferably about 15 to 25 seconds, but larger or smaller values can also be used. If the outcome of query  206  is NO (FALSE) indicating that engine  80  is not idling, or alternatively has not been idling for at least time t(i)=tc, then method  200  proceeds to ENABLE ENGINE step  208  wherein if engine  80  is running it continues to run or if engine  80  is not running, it may be started. Using query  206  in the form that determines whether idle time t(i) at least equals tc is preferred. 
     If the outcome of query  206  is YES (TRUE) indicating that engine  80  is running or that it has been idling for at least time t(i)=tc then method  200  proceeds to FUEL-LEVEL INCREASE RATE R(t)&gt;Rc ? query  210  wherein processor  72  uses fuel level sensor  82  to determine whether the increase in fuel level per unit time (i.e., the fueling rate R(t)) exceeds a predetermined fueling rate Rc. The parameter Rc may be stored in memory  77  or elsewhere in the vehicle electronics system and expressed in liters per second or gallons per minute or percent change per minute or second, or in whatever other units the system designer finds convenient. The sampling periods for determining R(t) should be long enough that transient sloshing of the fuel in the tank does not give false readings indicating fueling when none is actually taking place. If the outcome of query  210  is NO (FALSE) indicating that R(t)&lt;Rc, then method  200  proceeds to ENABLE ENGINE step  208  wherein engine  80  continues to run if already running or is allowed to start if not running, as has been previously explained. 
     If the outcome of query  210  is YES (TRUE) indicating that R(t)≧Rc, then method  200  proceeds to DISABLE ENGINE step  212  wherein engine  80  is shut off if running and prevented from started if not running. ENABLE ENGINE and DISABLE ENGINE are conveniently accomplished by engine control  78  in conjunction with processor  72 . Predetermined fueling rate parameter Rc is conveniently stored in memory  76  and is best chosen by the designer to avoid significant false positives from fuel sloshing and the like. The magnitude of Rc and the time period over which it is measured will depend upon the details of the fuel tank design on a particular vehicle, among other things, the capacity of the tank, whether anti-slosh baffles or sponges are included in the tank, the sensitivity and stability of fuel level sensor  82  and other factors that will be understood by persons of skill in the art. Thus, Rc is conveniently chosen by the designer based on the properties of the particular vehicle being fitted or designed with the present invention. Following DISABLE ENGINE step  212 , method  200  returns to start  202  and initial query  204  as shown by path  213 . Unless the disable switch is SET, method  200  will substantially maintain the vehicle in an ENGINE DISABLED (e.g., OFF) state during fueling and return it to an ENGINE ENABLED (e.g., ON or START ALLOWED) state when fueling is finished. 
     While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as set forth in the appended claims and the legal equivalents thereof.