Abstract:
There is provided a method of shutting down an engine, the engine having an air intake, and the method having the steps of attaching a valve to the air intake, the valve having an open position that allows air to pass into the air intake; using one or more sensors, detecting one or more predetermined engine conditions indicative of a runaway state; electromagnetically actuating the valve to move to a closed position preventing air from passing into the air intake once the one or more predetermined engine conditions have been detected; and causing the valve to return to the open position once a predetermined safe state has been reached.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    This relates to a method and apparatus for shutting down an engine by selectively preventing air from passing into the air intake. 
         [0003]    2. Description of the Related Art 
         [0004]    In some situations, such as when diesel vehicles are used on industrial sites where there is a risk of hydrocarbons being released into the air, it is necessary to have the ability to shut down the engine should it enter a runaway state. This is often done by way of an air shut off valve or an ESD valve. An example of an air shut off valve is disclosed in U.S. Pre-Grant Publication No. 2007/0186901 (Rivet) entitled “Engine Air Intake Shut Off Valve.” 
       BRIEF SUMMARY 
       [0005]    According to an aspect, there is provided a method of shutting down an engine having an air intake, the method comprising the steps of attaching a valve to the air intake of the engine, the valve having an open position that allows air to pass into the air intake; using one or more sensors, detecting one or more predetermined engine conditions indicative of a runaway state; electromagnetically actuating the valve to move to a closed position preventing air from passing into the air intake once at least one predetermined engine condition has been detected; and causing the valve to return to the open position once a predetermined safe state has been reached. 
         [0006]    According to another aspect, the valve may be biased toward the open position. The valve may be actuated by an actuator that switches between an unactuated state and an actuated state, the valve being moved to the closed position as the actuator switches to the actuated state. A connector may connect the valve and the actuator, the actuator applying a positive force to move the valve from the open position to the closed position and from the closed position to the open position. The actuator may be biased toward the unactuated state such that the valve is biased toward the open position by the actuator. The actuator may be a solenoid that is biased toward the unactuated state. The connector may comprise a rack and a pinion. The actuator may comprise a rotatable component and electromagnetically actuating the valve may comprise repelling the rotatable component from the unactuated state toward the actuated state. In the unactuated state the rotatable component may be magnetically attracted to a first rotational stop and the rotatable component may be adjacent to a second rotational stop in the actuated state. At least one of the rotatable component, the first rotational stop, and the second rotational stop comprises an electromagnet that electromagnetically actuates the actuator. The predetermined safe state may be a time delay. The at least one predetermined engine conditions may be an upper RPM threshold of the engine and the predetermined safe state may be a lower RPM threshold of the engine. 
         [0007]    According to an aspect, there is provided an engine air intake shut off device to be attached to an air intake of an engine. The device comprises a valve attachable to the air intake of the engine, the valve having an open position that allows air to pass into the air intake and a closed position that prevents air from passing into the air intake. An electromagnetic actuator is connected to the valve, the electromagnetic actuator moving the valve to the closed position when activated. There are one or more sensors that produce signals indicative of one or more engine conditions. There is also a controller that has instructions that cause the controller to activate the electromagnetic actuator in response to a signal from the one or more sensors indicative of a runaway state, and to cause the valve to return to the open position once a predetermined safe state has been reached. 
         [0008]    According to an aspect, the valve may be actuated by an actuator that moves between an unactuated state and an actuated state, the valve being moved to the closed position as the actuator moves to the actuated state. A connector may connect the valve and the actuator, the actuator applying a positive force to move the valve from the open position to the closed position and from the closed position to the open position. The actuator may be biased toward the unactuated state such that the valve is biased toward the open position by the actuator. The electromagnetic actuator may comprise first and second electromagnets, the first electromagnet being activated to repel a movable component from the open position to the closed position, and the second electromagnet being activated to repel the movable component from the closed position to the open position. The actuator may be a solenoid. The connector may comprise a rack and a pinion. The runaway state may be an upper RPM threshold of the engine and the predetermined safe state may be a lower RPM threshold of the engine. The predetermined safe state may be a time delay. 
         [0009]    According to an aspect, there is provided a magnetic actuator apparatus comprising a valve, a valve actuator having a first position defined by a first stop and a second position defined by a second stop, the valve actuator opening and closing the valve as it moves between the first and second positions; a first magnetic element carried by the valve actuator and a second magnetic element carried by the first stop, wherein each of the first magnetic element and the second magnetic element is an electromagnet or a permanent magnet, and wherein at least one of the first magnetic element and the second magnetic element is an electromagnet; a controller having instructions that cause the controller to change the polarity of at least one electromagnet to electromagnetically move valve actuator from the first position toward the second position in response to a first activation signal and change the polarity of at least one electromagnet to electromagnetically move the valve actuator from the second position toward the first position in response to a second activation signal. 
         [0010]    According to another aspect, the second stop may carry one of an electromagnet, a permanent magnet, and a ferrous element. The first magnetic element may be a permanent magnet, the second magnetic element may be a first electromagnet, and the second stop carries a second electromagnet. The first magnetic element may be an electromagnet and the second magnetic element may be a permanent magnet. One of the first and second electromagnets may be activated to repel the valve actuator, and the other one of the first and second electromagnets may be activated to attract the valve actuator. At least one of the first and second electromagnets may comprise a permanent magnet such that when the electromagnet is not activated, the valve actuator will continue to be attracted to the at least one of the first and second electromagnets. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0011]    These and other features will become more apparent from the following description in which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to be in any way limiting, wherein: 
           [0012]      FIG. 1  is a perspective view of an air intake valve assembly with the valve in an open position. 
           [0013]      FIG. 2  is a perspective view of an air intake valve assembly with the valve in a closed position. 
           [0014]      FIG. 3  is an exploded perspective view of an air intake valve assembly. 
           [0015]      FIG. 4  is a schematic view showing the connection between components. 
           [0016]      FIG. 5  is a schematic view showing the engine and air intake. 
           [0017]      FIG. 6  is a perspective view of an alternate air intake valve assembly with the valve in a closed position. 
           [0018]      FIG. 7  is a perspective view of an alternate air intake valve assembly with the valve in an open position. 
           [0019]      FIG. 8  is a perspective view of an alternate air intake valve assembly with a cover. 
           [0020]      FIG. 9  is a schematic view showing the alternate air intake valve assembly. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    A method and apparatus for shutting down an engine generally will now be described with reference to  FIGS. 1 through 9 . It will be understood that the problem with runaway engines is primarily limited to diesel engines, however the principles discussed below could be applied to other internal combustion engines that may be at risk of entering a runaway condition. A first embodiment of the air intake valve assembly will be described with specific reference to  FIG. 1  through  FIG. 3 , and a second embodiment of the air intake valve assembly will be described with reference to  FIG. 6  through  FIG. 9 . 
         [0022]    Referring to  FIG. 5 , engine  10  has air intake  12 . The apparatus for shutting down engine  10  has a valve  14 , which is attached to air intake  12 . Valve  14  is biased toward an open position that allows air to pass into air intake  12  of engine  10 . The air drawn through air intake  12  may be from the surrounding atmosphere, or it may be charged air, such as from a turbocharger or a supercharger on a vehicle engine. Preferably, valve  14  is a butterfly valve as shown in  FIG. 1  and as is commonly used in engines, although other valves may also be used as is known in the art. Referring to  FIG. 4 , engine  10  has one or more sensors  16 . Sensors  16  are used to measure engine parameters that may be used to identify a runaway state as are known in the art, for example, engine RPMs or temperature. Based on the type of sensors, the engine conditions that are indicative of a runaway state are predetermined. These engine conditions may, for example, be an upper RPM threshold of the engine  10  that indicates an engine speed above the normal operation parameters of the engine  10 , or a temperature that is beyond the safe range of operation for the engine  10 . Other conditions that indicate a potential runaway state may also be used. 
         [0023]    Valve  14  is connected to an electromagnetic actuator  18  by a connector  22 . Electromagnetic actuator  18  may be a solenoid  20  with connector  22  connected to a rack  23  and pinion  25  to move valve  14 , as shown in  FIG. 3 . Preferably, solenoid  20  is spring biased, such as by a pneumatic or metal spring, toward the unactuated position, such that it returns to the unactuated state when the electromagnetic force is deactivated. As can be seen, rack  23  moves laterally and engages pinion  25  to convert the lateral movement to rotational movement. Connector  22  is preferably covered by a cover  27  to protect the components. In the depicted example, valve  14  will be actuated between an open and closed position by actuator  18  as it moves between an unactuated state and an actuated state. While other types of connectors  22  may be used, preferably connector  22  is such that actuator  18  applies a positive force to both open and close the valve  14 . This allows actuator  18  to be biased to the unactuated position, and as the movement of valve  14  is controlled in both directions, this also has the effect of biasing valve  14  to the open position. 
         [0024]    Electromagnetic actuator  18  may also be a magnetic gate actuator  30  as shown in  FIG. 6 . Magnetic gate actuator  30  will be described in relation to a rotatable component that activates and deactivates. However, it will be understood that the same principles may be applied to a linearly moving component that interacts with a linearly moving valve. Magnetic gate actuator  30  has a pivotal connection  32  that allows for rotation of the rotatable component  34 . Rotatable component  34  carries an actuator magnetic element  35  and rotates between a first rotational stop  36  and a second rotational stop  38 . Rotational stops  36  and  38  may be stationary magnetic elements, although it will be understood that one of  36  and  38  may be a non-magnetic element, depending on the configuration of the electromagnet and permanent magnet. In the depicted example, at least one of magnetic elements  35 ,  36 , and  38  will be an electromagnet, while the other magnetic elements may be permanent magnets, or ferrous material such that pivoting component  34  is actuated from the open position to the closed position by applying a current to an electromagnet. The electromagnet electromagnetically actuates the actuator, rotatable component  34 . 
         [0025]    Rotatable component  34  is connected to valve  14  such that as pivoting component  34  is rotated between the two rotational stops  36  and  38 , valve  14  will change between the open position, as shown in  FIG. 7 , and the closed position, as shown in  FIG. 6 . In the unactuated state, the rotatable component  34  may be magnetically attracted to first rotational stop  36 , and may be adjacent to second rotational stop  38  in the actuated state. It will be understood by those skilled in the art that the roles of first and second rotational stops  36  and  38  may also be reversed. Rotatable component  34  may also be magnetically attracted to first rotational stop  36  in the unactuated state, and to second rotational stop  38  in the actuated state. Referring to  FIG. 8 , electromagnetic actuator  18  is preferably designed to be covered by a cover  40 . Referring to  FIG. 9 , magnetic gate actuator  30  is connected to controller  24 . 
         [0026]    When one or more of the predetermined engine conditions is detected by the sensors  16 , the valve  14  is actuated by electromagnetic actuator  18  and the valve  14  switches from an open position to a closed position in which air is prevented from passing into the air intake  12 . Referring to  FIG. 2  and  FIG. 6 , when valve  14  is in the closed position, engine  10  will be forced to shut down as there is no longer a source of combustion air. Predetermined safe states are then used to determine when it is safe for the valve  14  to return to the open position. These safe states may use different measures as will be understood by one in the art, and may make use of existing sensors  16  used to detect a potential runaway state, or different sensors. For example, the predetermined safe state could be a time delay that is sufficiently long that the engine  10  will have been forced to shut down, or it may be a lower speed threshold of the engine  10 , or a lower temperature of the engine  10 . Alternatively, it could be a combination of safe states, or different safe states in alternatives. Once a predetermined safe state is reached, electromagnetic actuator  18  moves valve  14  to the open position, allowing air flow through air intake  12 . In some embodiments, valve  14  may be biased toward the open position directly, and this may apply the force to move actuator  18  to the unactuated position once it is no longer energized. Preferably, sensors  16  and actuator  18  are controlled by a controller  24 , as shown in  FIG. 4 . When valve  14  is biased toward the open position, controller  24  may cause the valve to return to the open position by deactivating actuator  18 . Alternatively, controller  24  may activate actuator  18  to actively cause valve  14  to return to the open position. Controller  24  may also have a manual override switch  26  that a user can activate should a condition occur that is not detected by sensors  16  requiring emergency shutdown of engine  10 . Controller  24  may be any type of logic controller as may be known in the art that is able to be programmed to compare signals from sensors  16  to predetermined levels and to send other signals to activate or deactivate actuator  18  as well as perform other functions or control other components based on the particular embodiment being used. 
         [0027]    Referring to  FIG. 9 , when magnetic gate actuator  30  is used, valve  14  will be in the open position, as shown in  FIG. 7 , when the engine is running For example, stationary magnetic elements  36  and  38  may be permanent magnets with the same polarity facing magnetic element  35 , which is an electromagnet without a permanent polarity, or a polarity that may be switched by applying a current. The polarity of the electromagnet or electromagnets may be changed either by switching the induced polarity in the electromagnet, or by inducing a polarity in the electromagnet when it is in a neutral state. 
         [0028]    In the open position, magnetic element  35  is attracted to magnetic element  36  and may or may not be repelled from magnetic element  38 . In order to move to the closed position, magnetic element  35  is energized such that it is repelled from magnetic element  36  and attracted to magnetic element  38 . If it is desired to “latch” pivoting component  34  in the open state, magnetic element  35  may remain energized, or the system may be designed to ensure that magnetic element  35  remains attracted to magnetic element  38  when de-energized. Alternatively, the system may be designed such that, when de-energized, magnetic element  35  is repelled by magnetic element  38  and attracted to magnetic element  36  to return to a normally open position. 
         [0029]    In another alternative, magnetic element  36  may be a permanent magnet, magnetic element  38  may be non-polarized ferrous material, and magnetic element  35  may be an electromagnet. In this example, when magnetic element  35  is energized, it is repelled by magnetic element  36  and attracted to magnetic element  38 . When magnetic element  35  is de-energized, it will be neutral with respect to magnetic element  38  and attracted to magnetic element  36 . This design ensures that gate actuator  30  is able to close quickly, while allowing it to be biased toward the open position when de-activated. 
         [0030]    In other embodiments, magnetic element  35  may be a permanent magnet or non-polarized ferrous material and magnetic elements  36  and  38  may be electromagnets that control the movement of pivoting component  34  by selectively energizing and de-energizing. The various arrangements for doing so will be apparent to those skilled in the art. 
         [0031]    While it may be desirable to design the system such that pivoting component  34  is biased toward the open position under normal conditions, it may also be designed to be reset to the open position by a user, which may apply a current or turn off a current and allow pivoting component  34  to return to the open position. In one example, pivoting component  34  may be biased to the open position by programming a controller to cause the system to activate and return pivoting component  34  to the open position once the predetermined safe state has been reached. 
         [0032]    As depicted, there is a controller  24  that is programmed to control the activation and deactivation of some or all of magnetic elements  35 ,  36 , and  38 . If it does not occur automatically when the system deactivates, controller  24  may be programmed to cause valve  14  to return to the open position after the potential runaway state has ended and a safe state has been reached. Controller  24  may be programmed with instructions to change the polarity of at least one electromagnet to electromagnetically move the valve actuator  18  from the first position, where valve  14  is open, toward the second position, where valve  14  is closed, in response to a first activation signal. The polarity may be changed either by applying a current to the electromagnet in order to induce a polarity from a neutral state. It may also be possible to apply a current to reverse the polarity of the electromagnet, although this is less commonly done. While valve  14  may be physically or magnetically biased to return to the first position once a safe condition has been reached, valve  14  may also be biased by programming controller  24  to electromagnetically move the valve actuator  18  from the second position toward the first position in response to the second activation signal. The first and second positions are preferably defined by rotational stops  36  and  38 . 
         [0033]    As discussed above, valve actuator  18  and first and second stops  36  and  38  may be one of an electromagnet, a permanent magnet, and a non-magnetic, ferrous element, in a variety of combinations. Valve actuator  18  carries a first magnetic element  42 , first stop  36  carries a second magnetic element  44 , and second stop  38  may carry a third magnetic element  46 , or be non-magnetic. For example, in one embodiment, the first magnetic element carried by first stop  36  is a permanent magnet, the second magnetic element is a first electromagnet, and second stop  38  carries a second electromagnet. When both first stop  36  and second stop  38  carry electromagnets, one of the electromagnets may be activated to repel the movable component, while the other electromagnet may remain deactivated, or may be activated to attract the movable component. 
         [0034]    Alternatively, the first magnetic element may be an electromagnet, and the second magnetic element may be a permanent magnet. In this case, second stop  38  may be one of a permanent magnet, a ferrous element, or a non-magnetic stop. Preferably, the system is designed such that when the electromagnet is deactivated, the movable component  34  will continue to be attracted to either the first or second electromagnets to maintain valve actuator  18  in a position to hold valve  14  either open or closed. For example, at least one of the first and second magnetic elements may comprise a permanent magnet. As will be understood by those skilled in the art, the first, second, and third magnetic elements may be both electromagnets and permanent magnets. 
         [0035]    By allowing valve  14  to open when actuator  18  is no longer energized, or by causing actuator  18  to open valve  14  as it returns to the unactuated position, there is much less difficulty in resetting the shut-down device. This provides an advantage over devices that may have a reset shut-down circuit or a valve that must be resent manually, as these may fail in some circumstances, or be difficult to access in others. By providing sensors that also monitor for a safe state, operators are able to simply wait until conditions are safe before starting the engine again, and feel confident that the engine will start once the runaway condition has been addressed. 
         [0036]    In this patent document, the word “comprising” is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements. 
         [0037]    The scope of the following claims should not be limited by the preferred embodiments set forth in the examples above and in the drawings, but should be given the broadest interpretation consistent with the description as a whole.