Patent Publication Number: US-10760481-B1

Title: Magnetically-actuated variable-length connecting rod devices and methods for controlling the same

Description:
TECHNICAL FIELD 
     The present disclosure relates generally to connecting rod devices, and more particularly, to magnetically-actuated variable-length connecting rod devices and methods for controlling the same. 
     BACKGROUND 
     A connecting rod is generally known as a rigid member that provides the mechanical linkage between a piston of an engine, particularly a reciprocating engine such as an internal combustion engine, and a crank or crankshaft. The connecting rod functions as a lever arm by pushing and pulling the piston into and out of the cylinder, and converts the linear up-and-down movement of the piston into rotation of the crankshaft. This motion is then passed on to a series of devices capable of providing power to the machine, e.g., vehicle, in which the engine is equipped. 
     A common measure of engine power, which is dependent upon the connecting rod, is compression ratio, defined as the ratio between the swept volume of a cylinder with the piston at bottom dead center (BDC) and the swept volume of the cylinder with the piston at top dead center (TDC). Put more simply, compression ratio can refer to the ratio of maximum volume to minimum volume in the cylinder. When the connecting rod has a fixed length, the engine will have a fixed displacement and compression ratio, as the maximum and minimum volume in the cylinder are constant. 
     A fixed compression ratio, problematically, can result in missed performance optimization. For instance, under low engine loads, such as idling, a higher compression ratio can yield improved fuel economy. Meanwhile, under high engine loads, such as a large power request from the driver, a lower compression ratio, combined with increased boost, can yield improved power. 
     SUMMARY 
     The present disclosure provides a variable-length connecting rod device capable of dynamically changing engine displacement and compression ratio to improve overall vehicle efficiency by matching compression ratios to appropriate engine load conditions. The variable-length connecting rod device, as described herein, can vary the length of the connecting rod during operation of the engine to increase or decrease the engine&#39;s compression ratio in response to high or low engine loads, thereby optimizing engine performance. Furthermore, the variable-length connecting rod device, as described herein, can adjust the length of the connecting rod using magnetic forces, thereby eliminating unnecessary auxiliary components, such as motors, simplifying the connecting rod design, and reducing overall packaging size. 
     According to embodiments of the present disclosure, an apparatus can include: a piston head configured to be disposed inside of a cylinder of an engine; a connecting rod device coupled to the piston head and extending therefrom, the connecting rod device including: a variable-length connecting rod including a female component with a hollow body and a male component disposed at least partially inside of the female component, the female component configured to be coupled to a crankshaft of the engine, one or more rollers rotatably disposed in or on the male component, an outer surface of each roller configured to be in contact with an inner surface of the female component, and a connecting rod magnet movably coupled to the male component proximate to a position of the one or more rollers; and a piston coupling mechanism disposed at least partially inside of the piston head to couple the connecting rod device to the piston head, wherein the connecting rod device is configured to transition between a locked state, in which the female component is held in unison with the male component, and an unlocked state, in which the connecting rod magnet moves in response to a magnetic field proximate to the cylinder enabling rotation of the one or more rollers, allowing the female component to move independent of the male component along an axis of the connecting rod. 
     Furthermore, according to embodiments of the present disclosure, an apparatus can include: a piston head configured to be disposed inside of a cylinder of an engine; a connecting rod device coupled to the piston head and extending therefrom, the connecting rod device including: a variable-length connecting rod including a female component with a hollow body and a male component disposed at least partially inside of the female component, the female component configured to be coupled to a crankshaft of the engine; and a piston coupling mechanism disposed at least partially inside of the piston head to couple the connecting rod device to the piston head, the piston coupling mechanism including: first and second piston-cylinder coupling pads movably disposed at opposite axial ends of the piston coupling mechanism, respectively, and a piston coupling mechanism magnet movably disposed at least partially between the first and second piston-cylinder coupling pads, wherein the piston coupling mechanism is configured to transition between a retracted state, in which the first and second piston-cylinder coupling pads are positioned inside of an outer wall of the piston head, and an extended state, in which the piston coupling mechanism magnet moves in response to a magnetic field proximate to the cylinder causing the first and second piston-cylinder coupling pads to move along an axis of the piston coupling mechanism outside of the outer wall of the piston head, such that the first and second piston-cylinder coupling pads abut an inner surface of the cylinder to hold the piston head in place inside of the cylinder. 
     Furthermore, according to embodiments of the present disclosure, an apparatus can include: a piston head configured to be disposed inside of a cylinder of an engine; a connecting rod device coupled to the piston head and extending therefrom, the connecting rod device including: a variable-length connecting rod including a female component with a hollow body and a male component disposed at least partially inside of the female component, the female component configured to be coupled to a crankshaft of the engine, one or more rollers rotatably disposed in or on the male component, an outer surface of each roller in contact with an inner surface of the female component, and a connecting rod magnet movably coupled to the male component proximate to a position of the one or more rollers; and a piston coupling mechanism disposed at least partially inside of the piston head to couple the connecting rod device to the piston head, the piston coupling mechanism including: first and second piston-cylinder coupling pads movably disposed at opposite axial ends of the piston coupling mechanism, respectively, and a piston coupling mechanism magnet movably disposed at least partially between the first and second piston-cylinder coupling pads, wherein the connecting rod device is configured to transition between a locked state, in which the female component is held in unison with the male component, and an unlocked state, in which the connecting rod magnet moves in response to a magnetic field proximate to the cylinder enabling rotation of the one or more rollers, allowing the female component to move independent of the male component along an axis of the connecting rod, and wherein the piston coupling mechanism is configured to transition between a retracted state, in which the first and second piston-cylinder coupling pads are positioned inside of an outer wall of the piston head, and an extended state, in which the piston coupling mechanism magnet moves in response to the magnetic field causing the first and second piston-cylinder coupling pads to move along an axis of the piston coupling mechanism outside of the outer wall of the piston head, such that the first and second piston-cylinder coupling pads abut an inner surface of the cylinder to hold the piston head in place inside of the cylinder. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The embodiments herein may be better understood by referring to the following description in conjunction with the accompanying drawings in which like reference numerals indicate identically or functionally similar elements, of which: 
         FIGS. 1A and 1B  are views of an exemplary magnetically-actuated piston and connecting rod device with a variable-length connecting rod; 
         FIG. 2  is a select-component view of the magnetically-actuated piston and connecting rod device of  FIGS. 1A and 1B ; 
         FIGS. 3A-3D  are views of the magnetically-actuated piston and connecting rod device of  FIGS. 1A and 1B  when no current is applied to a solenoid wrapped around a cylinder of an engine; 
         FIGS. 4A-4D  are views of the magnetically-actuated piston and connecting rod device of  FIGS. 1A and 1B  when a current passes through the solenoid wrapped around the cylinder of the engine; 
         FIGS. 5A-C  are operational views showing an exemplary process of lengthening the connecting rod of the magnetically-actuated piston and connecting rod device of  FIGS. 1A and 1B ; 
         FIGS. 6A-C  are operational views showing an exemplary process of shortening the connecting rod of the magnetically-actuated piston and connecting rod device of  FIGS. 1A and 1B ; 
         FIGS. 7A and 7B  are views of an exemplary piston coupling mechanism when no current is applied to the solenoid wrapped around the cylinder of the engine; 
         FIGS. 8A and 8B  are views of the piston coupling mechanism of  FIGS. 7A and 7B  when a current passes through the solenoid wrapped around the cylinder of the engine; 
         FIGS. 9A and 9B  are views of another exemplary magnetically-actuated piston and connecting rod device with a variable-length connecting rod; 
         FIGS. 10A-10C  are views of the magnetically-actuated piston and connecting rod device of  FIGS. 9A and 9B  when no current is applied to the solenoid wrapped around the cylinder of the engine; 
         FIGS. 11A-11C  are views of the magnetically-actuated piston and connecting rod device of  FIGS. 9A and 9B  when a current passes through the solenoid wrapped around the cylinder of the engine; 
         FIG. 12  is a flowchart illustrating an exemplary procedure for controlling operation of a magnetically-actuated piston and connecting rod device; 
         FIG. 13  is the flowchart of  FIG. 12  showing an exemplary procedure for lengthening the connecting rod of the magnetically-actuated piston and connecting rod device; 
         FIG. 14  is the flowchart of  FIG. 12  showing an exemplary procedure for shortening the connecting rod of the magnetically-actuated piston and connecting rod device; 
         FIG. 15  is the flowchart of  FIG. 12  showing an exemplary procedure for lengthening the connecting rod of the magnetically-actuated piston and connecting rod device to achieve a torque increase; and 
         FIG. 16  is the flowchart of  FIG. 12  showing an exemplary procedure for shortening the connecting rod of the magnetically-actuated piston and connecting rod device after lengthening the connecting rod for improved torque. 
     
    
    
     It should be understood that the above-referenced drawings are not necessarily to scale, presenting a somewhat simplified representation of various preferred features illustrative of the basic principles of the disclosure. The specific design features of the present disclosure, including, for example, specific dimensions, orientations, locations, and shapes, will be determined in part by the particular intended application and use environment. 
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present disclosure. Further, throughout the specification, like reference numerals refer to like elements. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     It is understood that the term “vehicle” or “vehicular” or other similar term as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g., fuels derived from resources other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more sources of power, for example both gasoline-powered and electric-powered vehicles. 
     Additionally, it is understood that one or more of the below methods, or aspects thereof, may be executed by at least one control unit, or electronic control unit (ECU). The term “control unit” may refer to a hardware device that includes a memory and a processor. The memory is configured to store program instructions, and the processor is specifically programmed to execute the program instructions to perform one or more processes which are described further below. The control unit may control operation of units, modules, parts, devices, or the like, as described herein. Moreover, it is understood that the below methods may be executed by an apparatus comprising the control unit in conjunction with one or more other components, as would be appreciated by a person of ordinary skill in the art. 
     Furthermore, the control unit of the present disclosure may be embodied as non-transitory computer readable media containing executable program instructions executed by a processor, controller or the like. Examples of the computer readable mediums include, but are not limited to, ROM, RAM, compact disc (CD)-ROMs, magnetic tapes, floppy disks, flash drives, smart cards and optical data storage devices. The computer readable recording medium can also be distributed throughout a computer network so that the program instructions are stored and executed in a distributed fashion, e.g., by a telematics server or a Controller Area Network (CAN). 
     Referring now to embodiments of the present disclosure, the disclosed variable-length connecting rod device is capable of dynamically changing engine displacement and compression ratio. The connecting rod device includes one or more magnets which can be actuated in the presence of a magnetic field to lengthen or shorten the connecting rod. The magnetic field can be activated at specific times during operation of the engine to adjust the length of the connecting rod such that the resultant compression ratios are matched to appropriate engine load conditions, thus improving overall engine load conditions and performance. 
       FIGS. 1A and 1B  are views of an exemplary magnetically-actuated piston and connecting rod device with a variable-length connecting rod. As shown in  FIGS. 1A and 1B , the magnetically-actuated piston and connecting rod device  100  can include a piston head  110  coupled to a connecting rod device extending therefrom. The piston head  110  can be cylindrically shaped in some embodiments, but the shape of the piston head  110  is not limited thereto. The piston head  110  can be disposed inside of a cylinder  400  of an engine (not shown), particularly a reciprocating engine such as an internal combustion engine, and can travel vertically (depending on orientation) inside of the cylinder  400 . While only a single magnetically-actuated piston and connecting rod device  100  is shown in  FIGS. 1A and 1B  and throughout the remaining figures, a magnetically-actuated piston and connecting rod device  100 , as described in detail herein, can be disposed in each cylinder  400  of the engine. 
     The magnetically-actuated piston and connecting rod device  100  can further include a connecting rod device coupled to the piston head  110  and extending therefrom, as mentioned above. The connecting rod device can include a variable-length connecting rod with a male component  120  and a female component  130 . The female component  130  can be formed with an at least partially hollow body. The male component  120  can be formed such that at least a portion thereof can be movably inserted into the hollow body of the female component  130 . 
     A distal end of the male component  120  (closest to the piston head  110 ) can be inserted into the female component  130 , and a proximal end of the male component  120  (furthest from the piston head  110 ) can be formed with a circular opening configured to receive a crankshaft (not shown) of the engine  400 . Meanwhile, a proximal end of the female component  130  can include an opening configured to receive the distal end of the male component  120 , and a distal end of the female component can be coupled to the piston head  110  via the piston coupling mechanism  200 . 
     Each of the male component  120  and female component  130  can be cylindrically shaped in some embodiments, but the respective shapes of the male component  120  and female component  130  are not limited thereto. Under certain circumstances described in greater detail below, the male component  120  can move in and out of the female component  130  along the axis (longitudinal axis) of the connecting rod, thereby varying the length of the connecting rod. The female component  130 , meanwhile, can remain positionally fixed with respect to the connecting rod device by virtue of its connection to the piston head  110 . 
     The connecting rod device can further include first and second male-female coupling pads  140  disposed on opposite sides of the female component  130 . Under certain circumstances described in greater detail below, the first and second male-female coupling pads  140  can move perpendicular to the axis of the connecting rod. The respective inner walls of the first and second male-female coupling pads  140  can be cylindrically shaped so as to conform to the shape of the male component  120 . Thus, the first and second male-female coupling pads  140  can hold the male component  120  in unison with the female component  130  by applying opposing forces on the male component  120  in a direction perpendicular to the axis of the connecting rod. That is, the first and second male-female coupling pads  140  can push against each other with the male component  120  therebetween to hold the male component  120  in place inside of the female component  130 . 
     In greater detail,  FIG. 2  is a select-component view of the magnetically-actuated piston and connecting rod device  100 . For demonstration purposes, the first male-female coupling pad  140 , second linkage arm  171 , and second joint  163  are removed from view. As shown in  FIG. 2 , the respective inner walls of the first and second male-female coupling pads  140  can be formed with a curvature corresponding to the outer shape of the male component  120 . This can allow the first and second male-female coupling pads  140  to rigidly hold the male component  120  when no magnetic field is present. The first and second male-female coupling pads  140  can hold the male component  120  within the female component  130  at multiple possible positions, allowing for precise compression ratio adjustment. 
     Referring again to  FIGS. 1A and 1B , the connecting rod device can further include a connecting rod magnet  150 , which is a magnet coupled to the female component  130  of the variable-length connecting rod. In some embodiments, the connecting rod magnet  150  can be disposed on or around a portion of the body of the female component  130 , and shaped in a manner corresponding to the shape of the female component  130  (e.g., cylindrically shaped). As such, the connecting rod magnet  150  can be configured to move over the portion of the body of the female component  130  in response to a magnetic field proximate to the cylinder  400  of the engine along the axis of the connecting rod. Particularly, the connecting rod magnet  150  can move in a first direction in response to a magnetic field proximate to the cylinder  400  and in a second, opposite direction in response to deactivation of the magnetic field proximate to the cylinder  400 . 
     Disposed on opposite axial ends of the connecting rod magnet  150  can be a first spring  151  and a second spring  152 . The first and second springs  151 ,  152  can maintain the connecting rod magnet  150  in a default or centered position when no magnetic field proximate to the cylinder  400  is present. However, when a magnetic field proximate to the cylinder  400  is present, the first spring  151  which is located proximal (i.e., closer to the crankshaft) of the connecting rod magnet  150  can compress due to proximal movement of the connecting rod magnet  150  along the axis of the connecting rod. Axial movement of the connecting rod  150  in response to a magnetic field proximate to the cylinder  400  will be described in greater detail below. 
     The connecting rod device can further include a series of components connecting the connecting rod magnet  150  to the first and second male-female coupling pads  140 . For starters, a plurality of joints  161 ,  162 , and  163  can extend through respective portions of the connecting rod magnet  150  and the first and second male-female coupling pads  140 . The plurality of joints  161 ,  162 , and  163  can extend in a direction perpendicular to the axis of the connecting rod. In particular, as shown in  FIGS. 1A and 1B , a first joint  162  can extend through a portion of the first male-female coupling pad  140 , a second joint  163  can extend through a portion of the second male-female coupling pad  140 , and a third joint  161  can extend through a portion of the connecting rod magnet  150 . By virtue of the joints  161 ,  162 , and  163  being attached to the first and second male-female coupling pads  140  and the connecting rod magnet  150 , each of the joints  161 ,  162 , and  163  can move in unison with the first and second male-female coupling pads  140  and the connecting rod magnet  150 , respectively. 
     The plurality of joints  161 ,  162 , and  163  can be interconnected through a series of linkage arms  171  and  172 . For example, a first linkage arm  172  can adjoin the first joint  162 , which extends through a portion of the first male-female coupling pad  140 , to the third joint  161 , which extends through a portion of the connecting rod magnet  150 , and a second linkage arm  171  can adjoin the second joint  163 , which extends through a portion of the second male-female coupling pad  140 , to the third joint  161 . 
     In some embodiments, the linkage arms  171  and  172  can be made of a rigid material such that the linkage arms  171  and  172  do not bend in response to axial movement of the connecting rod magnet  150 . Because the linkage arms  171  and  172  adjoin the connecting rod magnet  150  to the first and second male-female coupling pads  140 , the axial movement of the connecting rod magnet  150 , which necessarily causes movement of the linkage arms  171  and  172  connected to the connecting rod magnet  150  by virtue of the third joint  161 , can produce a corresponding movement of the first and second male-female coupling pads  140 . 
     Moreover, axial movement of the connecting rod magnet  150  can cause the linkage arms  171  and  172  to move angularly, or rotate, thereby moving the first and second male-female coupling pads  140  in a direction perpendicular to the axis of the connecting rod. Indeed, when the connecting rod device is in the coupled state, the first and second linkage arms  171  and  172  can extend at a first angle with respect to the axis of the connecting rod, and when the connecting rod device is in the de-coupled state, the first and second linkage arms  171  and  172  can extend at a second angle, different from the first angle, with respect to the axis of the connecting rod. The perpendicular movement of the first and second male-female coupling pads  140  can de-couple the first and second male-female coupling pads  140  from the male component  120 , or, in other words, release the male component  120 , allowing the male component  120  to move freely inside of the female component  130  along the axis of the connecting rod due to rotation of the crankshaft, as described in greater detail below. 
     The connecting components can further include a guiding plate  180  disposed between the linkage arms  171  and  172  and the first and second male-female coupling pads  140 . The guiding plate  180  can be fixed to the female component  130  such that the guiding plate  180  does not move. In addition, the guiding plate  180  can be formed with a plurality of openings corresponding to the plurality of joints  161 ,  162 , and  163 , whereby each opening in the guiding plate can receive one of the joints  161 ,  162 , or  163 . The guiding plate openings can be formed with a width to accommodate the above-described movement of the plurality of joints  161 ,  162 , and  163 . Particularly, the guiding plate openings which receive the first joint  162  and the second joint  163 , respectively, can extend in a direction perpendicular to the axis of the connecting rod so as to accommodate the perpendicular movement of the first joint  162  and the second joint  163  (as the first and second male-female coupling pads  140  move perpendicularly), and similarly, the guiding plate opening which receives the third joint  161  can extend in a direction parallel to the axis of the connecting rod so as to accommodate the axial movement of the third joint  161  (as the connecting rod magnet  150  moves along the axis of the connecting rod). 
     In some embodiments, a first guiding plate  180  can be disposed on a first side of (e.g., above) the first and second male-female coupling pads  140 , and a second guiding plate  180  can be disposed on a second, opposite side of (e.g., below) the first and second male-female coupling pads  140 . In such case, the second guiding plate  180  can be disposed between the second side of the first and second male-female coupling pads  140  and a second pair of linkage arms  171  and  172  which interconnect the plurality of joints  161 ,  162 , and  163 . The first pair of linkage arms  171  and  172  can attach to respective first end regions (e.g., top) of the joints  161 ,  162 , and  163 , while the second pair of linkage arms  171  and  172  can attach to respective second, opposite end regions (e.g., bottom) of the joints  161 ,  162 , and  163 . In other embodiments, the connecting rod device can utilize only a single guiding plate  180  and single set of linkage arms  171  and  172 . 
     The magnetically-actuated piston and connecting rod device  100  can further include a piston coupling mechanism  200  disposed at least partially inside of the piston head  110  that couples the connecting rod device to the piston head  110 . The piston coupling mechanism  200  can be positioned inside of the piston head  110 , in the wrist pin cavity, for example, extending longitudinally in a direction perpendicular to the axis of the connecting rod. 
     In detail,  FIGS. 7A and 7B  are views of an exemplary piston coupling mechanism when a magnetic field proximate to the cylinder  400  is inactive (i.e., no current is applied to the solenoid  410 ), and  FIGS. 8A and 8B  are views of the piston coupling mechanism when such magnetic field is active (i.e., current passes through the solenoid  410 ). Activation and deactivation of the magnetic field proximate to the cylinder  400  will be described in greater detail below. 
     As shown in  FIGS. 7A, 7B, 8A, and 8B , the piston coupling mechanism  200  can include first and second piston-cylinder coupling pads  210  movably disposed at opposite axial ends of the piston coupling mechanism  200 , respectively. The first and second piston-cylinder coupling pads  210  can be configured to move along the axis of the piston coupling mechanism  200  (perpendicular to the axis of the connecting rod) in opposite directions of each other. In this regard, the piston head  110  can be formed with openings therein shaped to receive the first and second piston-cylinder coupling pads  210 , respectively. In a neutral state, the first and second piston-cylinder coupling pads  210  can be positioned inside of an outer wall of the piston head  110 ; however, these openings permit the first and second piston-cylinder coupling pads  210  to move along the axis of the piston coupling mechanism  200  outside of the outer wall of the piston head  110  under certain circumstances described in greater detail below. 
     The piston coupling mechanism  200  can further include a piston coupling mechanism magnet  220  movably disposed at least partially between the first and second piston-cylinder coupling pads  210 . The piston coupling mechanism magnet  220  can be formed with an opening through which a guiding rod  230  extends perpendicular to the axis of the piston coupling mechanism  200 . The guiding rod  230  can be attached at one end to a fixed base member  240  and extend outwardly therefrom. A spring  221  can be disposed on or around the guiding rod  230  between the piston coupling mechanism magnet  220  and the base member  240 . 
     The guiding rod  230  can be configured to guide the movement of the piston coupling mechanism magnet  220  in a direction perpendicular to the axis of the piston coupling mechanism  200 . In this regard, magnetic forces resulting from a magnetic field proximate to the cylinder  400  can push the piston coupling mechanism magnet  220  along the guiding rod  230  toward the base member  240  in a direction perpendicular to the axis of the piston coupling mechanism  200 . Such movement can compress the spring  221 . Upon deactivation of the magnetic field, the spring  221  can decompress causing the piston coupling mechanism magnet  220  to move in the opposite direction perpendicular to the axis of the piston coupling mechanism  200 , returning the piston coupling mechanism magnet  220  to its default state. 
     The piston coupling mechanism  200  can further include linkage arms  251  and  252 . For example, a first linkage arm  251  can adjoin the piston coupling mechanism magnet  220  to the first piston-cylinder coupling pad  210 , and a second linkage arm  252  can adjoin the piston coupling mechanism magnet  220  to the second piston-cylinder coupling pad  210  disposed at an opposite side of the piston coupling mechanism  200  as the first piston-cylinder coupling pad  210 . 
     In some embodiments, the linkage arms  251  and  252  can be made of a rigid material such that the linkage arms  251  and  252  do not bend in response to movement of the piston coupling mechanism magnet  220 . Because the linkage arms  251  and  252  adjoin the piston coupling mechanism magnet  220  to the first and second piston-cylinder coupling pads  210 , the movement of the piston coupling mechanism magnet  220  in a direction perpendicular to the axis of the piston coupling mechanism  200 , which necessarily causes movement of the linkage arms  251  and  252 , can produce a corresponding movement of the first and second piston-cylinder coupling pads  210 . 
     Moreover, movement of the piston coupling mechanism magnet  220  in a direction perpendicular to the axis of the piston coupling mechanism  200  can cause the linkage arms  251  and  252  to move angularly, or rotate, thereby moving the first and second piston-cylinder coupling pads  210  along the axis of the piston coupling mechanism  200 . Indeed, when the piston coupling mechanism  200  is in the retracted state, the first and second linkage arms  251  and  252  can extend at a first angle with respect to the axis of the piston coupling mechanism  200 , and when the piston coupling mechanism  200  is in the extended state, the first and second linkage arms  251  and  252  can extend at a second angle, different from the first angle, with respect to the axis of the piston coupling mechanism  200 . The axial movement of the first and second piston-cylinder coupling pads  210  can move the coupling pads  210  through the openings formed in the piston head  110  outside of the piston head  110 , such that the first and second piston-cylinder coupling pads  210  abut an inner surface of the cylinder  400  to immobilize or hold the piston head  110  in place inside of the cylinder  400 , as described in greater detail below. 
     When the magnetic field causing movement of the piston coupling mechanism magnet  220  is deactivated, the spring  221  can decompress, thus returning the piston coupling mechanism magnet  220  to its default position. The return movement of the piston coupling mechanism magnet  220  can retract the linkage arms  251  and  252  and pull the first and second piston-cylinder coupling pads  210  back to their retracted position inside of the walls of the piston head  110 . Thus, the piston coupling mechanism magnet  220  can be configured to move in a first direction in response to the magnetic field proximate to the cylinder  400  and in a second, opposite direction in response to deactivation of the magnetic field. 
     Referring next to  FIGS. 3A-3D  and  FIGS. 4A-4D , the operation of the magnetically-actuated piston and connecting rod device  100  can be described. In detail, the connecting rod device can be configured to transition between a “coupled state” and a “de-coupled state,” as explained below, in response to a magnetic field proximate to the cylinder  400  in which the magnetically-actuated piston and connecting rod device  100  is disposed. Also, the piston coupling mechanism  200  can be configured to transition between a “retracted state” and an “extended state,” as explained below, in response to the magnetic field proximate to the cylinder  400  in which the magnetically-actuated piston and connecting rod device  100  is disposed. 
     The magnetic field can be generated by wrapping a solenoid  410  (e.g., see  FIGS. 5A-C  and  6 A-C) around each cylinder  400  of the engine. When an electric current is applied to the solenoid  410 , such that the current passes through the coils of the solenoid  410 , magnetic forces act down the length of the cylinder  400 , thereby generating a magnetic field. The magnetic field can cause responsive movement of magnetic bodies within the magnetic field, such as the connecting rod magnet  150  or piston coupling mechanism magnet  220 , due to attractive or repulsive magnetic forces acting upon the bodies. 
     Referring first to  FIGS. 3A-3D , which include a perspective view, a side view, a top view, and a close-up perspective view, respectively, of the magnetically-actuated piston and connecting rod device  100 , no current is applied to the solenoid  410  which is wrapped around cylinder  400 . Thus, in the example of  FIGS. 3A-3D , the magnetic field proximate to the cylinder  400  may be inactive, resulting in the coupled state of the connecting rod device and the retracted state of the piston coupling mechanism  200 . 
     Here, the connecting rod magnet  150  can be held in a default or centered position by virtue of first and second springs  151  and  152 . While the connecting rod magnet  150  is centered, the first and second male-female coupling pads  140  can be withdrawn, i.e., positioned against the male component  120 , due to being connected to the connecting rod magnet  150  via the plurality of joints  161 ,  162  and  163  and linkage arms  171  and  172 . In this position, the respective inner surfaces of the first and second male-female coupling pads  140  can abut the outer surface of the male component  120  on opposing sides thereof in order to hold the male component  120  in place within the female component  130 . The first and second male-female coupling pads  140  can apply counteracting forces on the male component  120  in a direction perpendicular to the axis of the connecting rod. Therefore, the male component  120  can be held in unison with the female component  130 , and unable to move independently of the female component  130 , in the coupled state of the connecting rod device. 
     Additionally, in the absence of the magnetic field proximate to the cylinder  400 , the first and second piston-cylinder coupling pads  210  can be retracted, or withdrawn, in the piston head  110 . That is, the first and second piston-cylinder coupling pads  210  can be positioned inside of an outer wall of the piston head  110 . In this position, the piston head  110  is able to move freely within the cylinder  400  due to regular operation of the engine. 
     Next, referring to  FIGS. 4A-4D , which include a perspective view, a side view, a top view, and a close-up perspective view, respectively, of the magnetically-actuated piston and connecting rod device  100 , a current passes through the solenoid  410  wrapped around the cylinder  400 , thereby generating a magnetic field along the length of the cylinder  400 . Thus, in the example of  FIGS. 4A-4D , the magnetic field proximate to the cylinder  400  may be active, resulting in the de-coupled state of the connecting rod device and the extended state of the piston coupling mechanism  200 . 
     Here, the connecting rod magnet  150  can move down the length of the female component  130 , that is, proximally (toward the male component  120 ) along the axis of the connecting rod, in response to the generated magnetic field, thereby compressing the first spring  151  proximal of the connecting rod magnet  150 . Because the connecting rod magnet  150  is connected to the first and second male-female coupling pads  140  via the plurality of joints  161 ,  162 , and  163  and linkage arms  171  and  172 , the first and second male-female coupling pads  140  can move outwardly from the male component  120 , that is, perpendicular to the axis of the connecting rod, thus separating from the male component  120 . When the first and second male-female coupling pads  140  move in this manner, the male component  120  may no longer be rigidly held inside of the female component  130 , causing a release of the male component  120 , and a de-coupling of the male component  120  from the female component  130 . This can “unlock” the male component  120  such that it is allowed to move independent of the female component  130  along the axis of the connecting rod due to the inertia of the normal crankshaft motion (rotation), thereby adjusting the effective length of the connecting rod. The springs  151  and  152  can return the connecting rod magnet  150  to its centered, “default” position once the current applied to the solenoid  410  stops. 
     Additionally, in response to the generated magnetic field, the piston coupling mechanism  200  can be activated, causing the piston coupling mechanism magnet  220  to move along the guiding rod  230  in a direction perpendicular to the piston coupling mechanism  200  (toward the fixed base member  240 ). Such movement of the piston coupling mechanism magnet  220  can cause the first and second piston-cylinder coupling pads  210  to move along the axis of the piston coupling mechanism  200 , so as to extend beyond the outer wall of the piston head  110 , into the inner wall of the engine cylinder  400 . This can hold the piston head  110 , and the female component  130  attached thereto, in place inside of the cylinder  400 . 
     The de-coupling of the male component  120  and female component  130 , along with the coupling of the piston head  110  to the inner wall of the cylinder  400 , can enable the male component  120  to freely move within the female component  130  while current passes through the solenoid  410 . This can allow for dynamic adjustment of connecting rod length based on the point in time during the combustion cycle at which the current activates, as described in greater detail with reference to  FIGS. 12-16 . 
     Next,  FIGS. 5A-C  are operational views showing an exemplary process of lengthening the connecting rod of the magnetically-actuated piston and connecting rod device  100 , and  FIGS. 6A-C  are operational views showing an exemplary process of shortening the connecting rod of the magnetically-actuated piston and connecting rod device  100 . In each of  FIGS. 5A-C  and  6 A-C, the vertically extending helix line represents the solenoid  410  wrapped around the cylinder  400 . It is to be understood that the depictions of  FIGS. 5A-C  and  6 A-C can replicated in each cylinder  400  of the engine. As a result, the compression ratio of each cylinder  400  can be individually adjusted. 
     Referring first to  FIGS. 5A-C , the engine is operating, and the piston head  110  can be positioned at or near top dead center (TDC) at stage A. Here, no electric current is applied to the solenoid  410 , and thus the magnetic field proximate to the cylinder  400  is inactive. That is, there can be no magnetic field capable of moving magnetic bodies in the magnetically-actuated piston and connecting rod device  100 . In such case, the connecting rod device can be in the coupled state, and the piston coupling mechanism can be in the retracted state, as explained above. 
     At stage B, current can be passed through the solenoid  410 , generating a magnetic field along the length of the cylinder  400 . This can activate the connecting rod magnet  150  of the connecting rod device and the piston coupling mechanism magnet  220  of the piston coupling mechanism  200  due to magnetic forces acting in the direction shown by the arrows through solenoid  410 . As explained above, activation of the connecting rod magnet  150 , whereby the connecting rod magnet  150  moves proximally along the axis of the connecting rod, can transition the connecting rod device to the de-coupled state in which the first and second male-female coupling pads  140  release the male component  120 , allowing the male component  120  to move independently of the female component  130 . Similarly, activation of the piston coupling mechanism magnet  220 , whereby the piston coupling mechanism magnet  220  moves down the length of the guiding rod  230  in a direction perpendicular to an axis of the piston coupling mechanism  200  (toward the base member  240 ), can transition the piston coupling mechanism  200  to the extended state. Here, the downward movement of the piston coupling mechanism magnet  220  can cause the linkage arms  251  and  252  to push the first and second piston-cylinder coupling pads  210  along the axis of the piston coupling mechanism  200 , in opposite directions, outside of an outer wall of the piston head  110 , such that the first and second piston-cylinder coupling pads  210  abut an inner surface of the cylinder  400  to immobilize or hold the piston head  110  in place inside of the cylinder  400 . Consequently, inertia due to the regular rotational motion of the crankshaft can pull on the male component  120 , causing the male component  120  to slide vertically out of the female component  130 , while the female component  130  is prevented from moving vertically due to its connection to the fixed piston head  110 . 
     At stage C, the current applied to the solenoid  410  can be deactivated. In response, the connecting rod device can transition back to the coupled state, in which the male and female components  120  and  130  are coupled together, and the piston coupling mechanism  200  can transition back to the retracted state, in which the piston head  110  is de-coupled from the inner walls of the cylinder  400 . The effective length of the connecting rod is now longer than if current had not be activated. 
     Referring next to  FIGS. 6A-C , the engine is operating, and the piston head  110  can be positioned at or near bottom dead center (BDC) at stage A—as opposed to TDC at stage A of  FIGS. 5A-C . Here, no electric current is applied to the solenoid  410 , and thus the magnetic field proximate to the cylinder  400  is inactive. That is, there can be no magnetic field capable of moving magnetic bodies in the magnetically-actuated piston and connecting rod device  100 . In such case, the connecting rod device can be in the coupled state, and the piston coupling mechanism can be in the retracted state, as explained above. 
     At stage B, current can be passed through the solenoid  410 , generating a magnetic field along the length of the cylinder  400 . This can activate the connecting rod magnet  150  of the connecting rod device and the piston coupling mechanism magnet  220  of the piston coupling mechanism  200  due to magnetic forces acting in the direction shown by the arrows through solenoid  410 . As explained above, activation of the connecting rod magnet  150 , whereby the connecting rod magnet  150  moves proximally along the axis of the connecting rod, can transition the connecting rod device to the de-coupled state in which the first and second male-female coupling pads  140  release the male component  120 , allowing the male component  120  to move independently of the female component  130 . Similarly, activation of the piston coupling mechanism magnet  220 , whereby the piston coupling mechanism magnet  220  moves down the length of the guiding rod  230  in a direction perpendicular to an axis of the piston coupling mechanism  200  (toward the base member  240 ), can transition the piston coupling mechanism  200  to the extended state. Here, the downward movement of the piston coupling mechanism magnet  220  can cause the linkage arms  251  and  252  to push the first and second piston-cylinder coupling pads  210  along the axis of the piston coupling mechanism  200 , in opposite directions, outside of an outer wall of the piston head  110 , such that the first and second piston-cylinder coupling pads  210  abut an inner surface of the cylinder  400  to immobilize or hold the piston head  110  in place inside of the cylinder  400 . Consequently, inertia due to the regular rotational motion of the crankshaft can push the male component  120 , causing the male component  120  to slide vertically into the female component  130 , while the female component  130  is prevented from moving vertically due to its connection to the fixed piston head  110 . 
     At stage C, the current applied to the solenoid  410  can be deactivated. In response, the connecting rod device can transition back to the coupled state, in which the male and female components  120  and  130  are coupled together, and the piston coupling mechanism  200  can transition back to the retracted state, in which the piston head  110  is de-coupled from the inner walls of the cylinder  400 . The effective length of the connecting rod is now shorter than if current had not be activated. 
     The connecting rod device, as described herein, is not limited solely to the design described herein above. Various modifications to the connecting rod device are acceptable, as would be appreciated by a person of ordinary skill in the art, so long as such changes are consistent with the scope of the accompanying claims. 
     For example,  FIGS. 9A and 9B  are views of another exemplary magnetically-actuated piston and connecting rod device with a variable-length connecting rod. As shown in FIGS.  9 A and  9 B, the magnetically-actuated piston and connecting rod device  300  can include a piston head  310 , which can generally correspond to the piston head  110  described hereinabove, coupled to a connecting rod device extending therefrom. The piston head  310  can be disposed inside of the cylinder  400 . While only a single piston and connecting rod device  300  is shown in  FIGS. 9A and 9B , the magnetically-actuated piston and connecting rod device  300  can be disposed in each cylinder  400  of the engine. 
     The magnetically-actuated piston and connecting rod device  300  can further include a connecting rod device coupled to the piston head  310  and extending therefrom. Generally similar to the connecting rod device of the magnetically-actuated piston and connecting rod device  100  described hereinabove, the connecting rod device of the magnetically-actuated piston and connecting rod device  300  can include a variable-length connecting rod with a male component  320  and a female component  330 . The female component  330  can be formed with an at least partially hollow body. The male component  320  can be formed such that at least a portion thereof can be disposed inside of the hollow body of the female component  330 . 
     In contrast with the magnetically-actuated piston and connecting rod device  100 , a proximal end of the male component  320  (furthest from the piston head  310 ) can be inserted into the female component  330 , and a distal end of the male component  320  (closest to the piston head  310 ) can be coupled to the piston head  310  via the piston coupling mechanism  200 . (The piston coupling mechanism  200  can operate in the same manner as described hereinabove and thus remain unchanged.) Meanwhile, a distal end of the female component  330  can include an opening configured to receive the proximal end of the male component  320 , and a proximal end of the female component  330  can be formed with a circular opening configured to receive the crankshaft (not shown). 
     Each of the male component  320  and female component  330  can be rectangularly shaped in some embodiments, but the respective shapes of the male component  320  and female component  330  are not limited thereto. Under certain circumstances as described herein, the female component  330  can move back and forth over the male component  320  along the axis of the connecting rod, thereby varying the length of the connecting rod. The male component  320 , meanwhile, can remain positionally fixed with respect to the connecting rod device by virtue of its connection to the piston head  310 . 
     The connecting rod device can further include a plurality of rollers  340  rotatably disposed in or on the male component  320 . The rollers  340  can be wheel-like, i.e., circularly shaped with a circumferential base portion, and capable of rotation about an axis. The rollers  340  can be disposed partially inside of the body of the male component  320  such that a portion of each roller  340  extends outside of an outer wall of the male component  320 . As such, an outer surface of one or more of the rollers  340  can come into contact with an inner surface of the female component  330  when a portion of the male component  320  is positioned therein, allowing the male component  320  to slide within the female component  330 . In some embodiments, the rollers  340  can include one or more first rollers  340  disposed at a first side of the male component  320  and one or more second rollers  340  disposed at a second, opposite side of the male component  320 . While the rollers  340  may be referred to herein in the plural, it is to be understood that the connecting rod device can include only a single roller  340  in certain embodiments. 
     The connecting rod device can further include a connecting rod magnet  350 , which is a magnet movably coupled to the male component  320  proximate to the position of the plurality of rollers  340 . In some embodiments, the connecting rod magnet  350  can be disposed entirely inside of the body of the male component  320 , as shown in the cross-sectional views of  FIGS. 10A-10C and 11A-11C . The connecting rod magnet  350  can be configured to move along the axis of the connecting rod in response to a magnetic field that is generated proximate to the cylinder  400 . 
     Moreover, under certain circumstances described below, an outer surface the connecting rod magnet  350  can come into contact with the respective outer surfaces of the rollers  340  in order to prevent rotation thereof. To this end, the connecting rod magnet  350  can be formed with one or more curved surfaces each of which adjacent to a respective position of the rollers  340 . The curvature of the connecting rod magnet  350 , visible in  FIGS. 10A-10C and 11A-11C , can match or be similar to the curvature of the rollers  340  to maximize surface contact, i.e., friction, between the connecting rod magnet  350  and the rollers  340 . 
     The connecting rod device can further include springs  351  and  352  disposed on opposite axial ends of the connecting rod magnet  350 . For example, the first spring  351  can be disposed proximally of the connecting rod magnet  350 , and the second spring  352  can be disposed distally of the connecting rod magnet  350 . Proximal movement of the connecting rod magnet  350  (toward the female component  330 ) along the axis of the connecting rod, in response to a magnetic field proximate to the cylinder  400 , can cause the first spring  351  to compress. Upon deactivation of the magnetic field, the first spring  351  can decompress to return the connecting rod magnet  350  to its default or centered position. It is to be understood that the springs  351  and  352  are not limited in their respective amounts. That is, the first spring  351  may include one or multiple first springs, and the second spring  352  may include one or second first springs. 
     Referring next to  FIGS. 10A-10C  and  FIGS. 11A-11C , the operation of the magnetically-actuated piston and connecting rod device  300  can be described. In detail, the connecting rod device can be configured to transition between a “locked state” and a “unlocked state” (similar to the aforementioned “coupled” and “de-coupled” states, respectively), as explained below, in response to a magnetic field proximate to the cylinder  400  in which the magnetically-actuated piston and connecting rod device  300  is disposed. As previously explained, the piston coupling mechanism  200  can be configured to transition between a “retracted state” and an “extended state,” as explained below, in response to the magnetic field proximate to the cylinder  400  in which the magnetically-actuated piston and connecting rod device  300  is disposed. 
     As described above, the magnetic field can be generated by wrapping a solenoid  410  (e.g., see  FIGS. 5A-C  and  6 A-C) around each cylinder  400  of the engine. When an electric current is applied to the solenoid  410 , such that the current passes through the coils of the solenoid  410 , magnetic forces act down the length of the cylinder  400 , thereby generating a magnetic field. The magnetic field can cause responsive movement of magnetic bodies within the magnetic field, such as the connecting rod magnet  350  or piston coupling mechanism magnet  220 , due to attractive or repulsive magnetic forces acting upon the bodies. 
     Referring first to  FIGS. 10A-10C , which include a cross-sectional perspective view, a cross-sectional top view, and a cross-sectional side view, respectively, of the magnetically-actuated piston and connecting rod device  300 , no current is applied to the solenoid  410  which is wrapped around cylinder  400 . Thus, in the example of  10 A- 10 C, the magnetic field proximate to the cylinder  400  may be inactive, resulting in the locked state of the connecting rod device and the retracted state of the piston coupling mechanism  200 . 
     Here, the connecting rod magnet  350  can be held in a default or centered position by virtue of first and second springs  351  and  352 . While the connecting rod magnet  350  is centered, the rollers  340  can be prevented from rotating due to the connecting rod magnet  350  abutting or pressing against the outer circumferential surfaces of the rollers  340 . As a result, the male component  320  can be locked in place inside of the female component  330  such that the male and female components  320  and  330  are held in unison. In this position, the female component  330  is prevented from sliding along the rollers  340 , as the rollers  340  are unable to rotate. 
     Additionally, in the absence of the magnetic field proximate to the cylinder  400 , the first and second piston-cylinder coupling pads  210  can be retracted, or withdrawn, in the piston head  310 . That is, the first and second piston-cylinder coupling pads  210  can be positioned inside of an outer wall of the piston head  310 . In this position, the piston head  310  is able to move freely within the cylinder  400  due to regular operation of the engine. 
     Next, referring to  FIGS. 11A-11C , which include a cross-sectional perspective view, a cross-sectional top view, and a cross-sectional side view, of the magnetically-actuated piston and connecting rod device  300 , a current passes through the solenoid  410  wrapped around the cylinder  400 , thereby generating a magnetic field along the length of the cylinder  400 . Thus, in the example of  FIGS. 11A-11C , the magnetic field proximate to the cylinder  400  may be active, resulting in the unlocked state of the connecting rod device and the extended state of the piston coupling mechanism  200 . 
     Here, the connecting rod magnet  350  can move down the length of the male component  320 , that is, proximally (toward the female component  330 ) along the axis of the connecting rod, in response to the generated magnetic field, thereby compressing the first spring  351  proximal of the connecting rod magnet  350 . The proximal movement of the connecting rod magnet  350  can separate the magnet  350  from the rollers  340 , allowing them to rotate. This, in turn, can allow for the inner surface of the female component  330  to slide along the rotating rollers  340  such that the female component  330  moves freely over the male component  320 . By “unlocking” the female component  330 , it is allowed to move independent of the male component  320  along the axis of the connecting rod due to the inertia of the normal crankshaft motion (rotation), thereby adjusting the effective length of the connecting rod. The springs  351  and  352  can return the connecting rod magnet  350  to its centered, “default” position once the current applied to the solenoid  410  stops. 
     Additionally, in response to the generated magnetic field, the piston coupling mechanism  200  can be activated, causing the piston coupling mechanism magnet  220  to move along the guiding rod  230  in a direction perpendicular to the piston coupling mechanism  200  (toward the fixed base member  240 ). Such movement of the piston coupling mechanism magnet  220  can cause the first and second piston-cylinder coupling pads  210  to move along the axis of the piston coupling mechanism  200 , so as to extend beyond the outer wall of the piston head  310 , into the inner wall of the engine cylinder  400 . This can hold the piston head  310 , and the male component  320  attached thereto, in place inside of the cylinder  400 . 
     The unlocking of the female component  330  from the male component  320 , along with the coupling of the piston head  310  to the inner wall of the cylinder  400 , can enable the female component  330  to freely move over the male component  320  while current passes through the solenoid  410 . Like the magnetically-actuated piston and connecting rod device  100 , this can allow for dynamic adjustment of connecting rod length based on the point in time during the combustion cycle at which the current activates, as described in greater detail with reference to  FIGS. 12-16 . 
     Next,  FIGS. 12-16  demonstrate methods for controlling operation of a magnetically-actuated piston and connecting rod device described herein (e.g., magnetically-actuated piston and connecting rod device  100 , magnetically-actuated piston and connecting rod device  300 , etc.). Particularly,  FIG. 12  is a flowchart  500  illustrating an exemplary procedure for controlling operation of a magnetically-actuated piston and connecting rod device;  FIG. 13  includes the flowchart  500  showing an exemplary procedure for lengthening the connecting rod of the magnetically-actuated piston and connecting rod device;  FIG. 14  includes the flowchart  500  showing an exemplary procedure for shortening the connecting rod of the magnetically-actuated piston and connecting rod device;  FIG. 15  includes the flowchart  500  showing an exemplary procedure for lengthening the connecting rod of the magnetically-actuated piston and connecting rod device to achieve a torque increase; and  FIG. 16  includes the flowchart  500  showing an exemplary procedure for shortening the connecting rod of the magnetically-actuated piston and connecting rod device after lengthening the connecting rod for improved torque. 
     As shown in  FIGS. 12-16 , the procedure  500  may start at step  505 , and continue to step  510 , where, as described in greater detail below, operation of the herein-disclosed magnetically-actuated piston and connecting rod device can be controlled so as to lengthen or shorten the variable-length connecting rod in response to specific load conditions. For the purpose of  FIGS. 12-16 , it assumed that the magnetically-actuated piston and connecting rod device is equipped in an engine of a vehicle. However, the magnetically-actuated piston and connecting rod device described herein is not limited solely to vehicles, but can be equipped in any engine-powered machine. 
     At step  505 , an engine (not shown) can be started, whereby the engine includes one or more cylinders  400  around which the solenoid  410  is wrapped. It is to be understood that the control logic illustrated throughout  FIGS. 12-16  can be implemented individually for each magnetically-actuated piston and connecting rod device disposed in each cylinder  400  of the engine. 
     At step  510 , a plurality of vehicle measurements can be acquired. Such vehicle measurements can represent the basis upon which the current load conditions are determined. In some embodiments, a vehicle controller area network (CAN) controller in communication, via an in-vehicle network, with a plurality of sensors disposed throughout the vehicle can acquire the vehicle measurements from individual sensors. For example, such vehicle measurements can include, but are not limited to, an accelerator or throttle position via an accelerator position sensor (APS), a vehicle speed (VS) via a vehicle speed sensor, a crankshaft position (CRS_Pos) and a camshaft position (CAM_Pos), a cylinder pressure (Cyl_Press) via a pressure sensor, an engine load percentage (Eng_Load) via an engine load sensor, an effective length of the variable-length connecting rod (CR_Length) via a proximity sensor, or any combination thereof. It is to be understood that the sensors for detecting these vehicle measurements are not limited solely to those listed above. 
     Additionally, one or more parameters for controlling the variable-length connecting rod can be managed throughout the procedure  500 . For example, activation of the solenoid  410  wrapped around the cylinder  400  can be tracked and controlled using ‘SolActive’. SolActive can be a binary parameter set to either 0 or 1. For example, when no current is applied to the solenoid  410 , such that the magnetic field proximate to the cylinder  400  is deactivated, and magnetic bodies in the magnetically-actuated piston and connecting rod device are in a default or centered position, SolActive can be set to 0. Conversely, when a current passes through the solenoid  410 , such that the magnetic field proximate to the cylinder  400  is active, causing movement of the magnetic bodies in the magnetically-actuated piston and connecting rod device, as described above, SolActive can be set to 1. 
     At step  515 , the vehicle speed and cylinder pressure can be compared with predetermined thresholds to determine whether initial conditions are satisfactory to adjust the variable-length connecting rod. For example, the vehicle speed can be compared with a predefined minimum speed, e.g., 20 kph, and the cylinder pressure can be compared with a predefined maximum pressure, e.g.,  2000  kPA. 
     If the vehicle speed is less than or equal to the predefined minimum speed or the cylinder pressure is greater than or equal to the predefined maximum pressure, the procedure  500  can proceed to step  555 , whereby the connecting rod device can operate without adjustment, that is, without lengthening or shortening the connecting rod. Here, the SolActive parameter can be set to 0 to preclude current from passing through the solenoid  410 . The magnetic field proximate to the cylinder  400  can be deactivated as a result. This can cause the connecting rod device to operate in a manner similar to a conventional fixed-length connecting rod. 
     Conversely, if the vehicle speed is greater than the predefined minimum speed and the cylinder pressure is less than the predefined maximum pressure, the procedure  500  can proceed to step  520  and beyond, where it can be determined whether one or more conditions are satisfied upon which the length of the connecting rod can be adjusted by supplying current to pass through the solenoid  410 . Particularly, the load conditions of the engine can be verified to adjust the connecting rod length in accordance with the current load, thus improving the compression ratio and overall driving efficiency. To this end, when low or high load conditions are experienced, the variable-length connecting rod can be lengthened or shortened by activating the current passing through the solenoid  410  at a specific point in time, that is, at a predefined position of the piston in the cylinder  400 , e.g., top dead center (TDC), bottom dead center (BDC), etc., and a predefined combustion stroke of the piston, e.g., exhaust (EXH), intake (INT), compression (COM), etc. Particularly, the engine compression ratio can be varied to best suit engine load conditions by passing a current through the solenoid  410  during the intake or exhaust stroke, as described below. 
     At step  520 , the respective positions of the crankshaft and the camshaft can be detected in order to confirm the current position of the piston in the cylinder  400  (i.e., “first condition”) and the current combustion stroke of the piston (i.e., “second condition”). If the position of the crankshaft indicates that the piston is located at top dead center in the cylinder  400  (in(CRS_Pos.TDC)==1), i.e., “first position,” and the position of the camshaft indicates that the combustion stroke of the engine is the exhaust stroke (in(CAM_Pos.EXH)==1), i.e., “first stroke,” the timing can be satisfactory for activating the current passing through the solenoid  410  when low load engine conditions are satisfied (step  525 ). If either of the above conditions are not satisfied, however, the respective positions of the crankshaft and the camshaft can be re-evaluated at step  530  to confirm the current position of the piston in the cylinder  400  and the current combustion stroke of the piston. If the position of the crankshaft indicates that the piston is located at bottom dead center in the cylinder  400  (in(CRS_Pos.BDC)==1), i.e., “second position,” and the position of the camshaft indicates that the combustion stroke of the engine is the intake stroke (in(CAM_Pos.INT)==1), i.e., “second stroke,” the timing can be satisfactory for activating the current passing through the solenoid  410  when high load engine conditions are satisfied in (step  535 ). In some embodiments, a proximity sensor can be used to assess how far the piston head  110  is from the top of the cylinder  400  to confirm the piston is at top dead center or the bottom of the cylinder  400  to confirm the piston is at bottom dead center within approximately +/−5 degrees. 
     Low or high load engine conditions can be verified in a variety of ways, including comparing the current engine load with a predefined engine load threshold and comparing the current accelerator position with a predefined accelerator position. For example, an accelerator position threshold value and engine load threshold value, below which the engine load is low and above which the engine load is high, can be predefined. Using this approach in step  525 , if the current accelerator position is less than or equal to a predefined accelerator position threshold value, e.g., 20%, and the current engine load is less than or equal to a predefined engine load threshold value, e.g., 35%, it can be determined that low load conditions are present. Conversely, in step  535 , if the current accelerator position is greater than the predefined accelerator position threshold value, e.g., 20%, and the current engine load is greater than the predefined engine load threshold value, e.g., 35%, it can be determined that high load conditions are present. 
     If the piston is located at top dead center, the combustion stroke of the engine is the exhaust stroke, and low engine load conditions are confirmed, the procedure  500  can proceed to step  545  where it can be determined whether the current effective length of the connecting rod is at its maximum. If the effective length of the connecting rod is not already maximized, the connecting rod can be lengthened by applying an electric current to the solenoid  410  wrapped around the cylinder  400  (SolActive=1) such that the current passes through the solenoid  410  to generate a magnetic field that activates magnetic bodies of the magnetically-actuated piston and connecting rod device in the manner described above (step  560 ). By generating the magnetic field while the piston is located at top dead center during the exhaust stroke, the connecting rod can be continuously lengthened as the male component  120  is pulled further out of the female component  130 , thereby increasing the effective length of the connecting rod during low load conditions to improve driving performance, as demonstrated in  FIG. 13 . 
     On the other hand, if the piston is located at bottom dead center, the combustion stroke of the engine is the intake stroke, and high engine load conditions are confirmed, the procedure  500  can proceed to step  545  where it can be determined whether the current effective length of the connecting rod is at its minimum. If the effective length of the connecting rod is not already minimized, the connecting rod can be shortened by applying an electric current to the solenoid  410  wrapped around the cylinder  400  (SolActive=1) such that the current passes through the solenoid  410  to generate a magnetic field that activates magnetic bodies of the magnetically-actuated piston and connecting rod device in the manner described above (step  560 ). By generating the magnetic field while the piston is located at bottom dead center during the intake stroke, the connecting rod can be continuously shortened as the male component  120  is pushed further into the female component  130 , thereby decreasing the effective length of the connecting rod during high load conditions to improve driving performance, as demonstrated in  FIG. 14 . 
     Meanwhile, if the current is passed through the solenoid  410  while the piston is located at top dead center during the compression stroke, and the spark timing is delayed until the connecting rod is lengthened (due to activating the solenoid current while the piston is at top dead center), an increased torque on the crankshaft can be produced during the power stroke due to the crankshaft being rotated further away from the top dead center position when initial power delivery occurs. In detail,  FIG. 15  illustrates a procedure for lengthening the variable-length connecting rod to improve engine torque. At step  540 , it can be determined whether the crankshaft is positioned such that the piston is located at top dead center through approximately 30 degrees clockwise (in(CRS_Pos.TT)==1), and the position of the camshaft indicates that the combustion stroke of the engine is the compression stroke (in(CAM_Pos.COM)==1). If both of the above conditions are satisfied, the procedure  500  can proceed to step  545  where it can be determined whether the current effective length of the connecting rod is at its maximum. If the effective length of the connecting rod is not already maximized, the connecting rod can be lengthened by supplying the current to the solenoid  410  (SolActive=1) such that the current passes through the solenoid  410  to generate a magnetic field that activates magnetic bodies of the magnetically-actuated piston and connecting rod device in the manner described above (step  560 ). Moreover, the spark can be delayed until the current passing through the solenoid  410  is deactivated to produce a higher torque delivery from a larger moment arm in the connecting rod device. 
       FIG. 16  illustrates a shortening for lengthening the variable-length connecting rod to improve engine torque. At step  550 , it can be determined whether the crankshaft is positioned such that the piston is located at bottom dead center through approximately 30 degrees clockwise (in(CRS_Pos.TB)==1), and the position of the camshaft indicates that the combustion stroke of the engine is the exhaust stroke (in(CAM_Pos.EXH)==1). If both of the above conditions are satisfied, the procedure  500  can proceed to step  545  where it can be determined whether the current effective length of the connecting rod is at its minimum. If the effective length of the connecting rod is not already minimized, the connecting rod can be shortened to return the connecting rod to its original length (before the compression stroke) by re-supplying the current to the solenoid  410  (SolActive=1) such that the current passes through the solenoid  410  to generate a magnetic field that activates magnetic bodies of the magnetically-actuated piston and connecting rod device in the manner described above (step  560 ). Therefore, the connecting rod length can continually increase near top dead center of the compression stroke, then decrease near bottom dead center of the following exhaust stroke. The adjustment of connecting rod length during these times can enable better torque delivery to the crankshaft. 
     The procedure  500  can continue throughout operation of the engine and end upon deactivation of the engine. The techniques by which the steps of procedure  500  may be performed, as well as ancillary procedures and parameters, are described in detail above. 
     It should be noted that the steps shown in  FIGS. 12-16  are merely examples for illustration, and certain other steps may be included or excluded as desired. Further, while a particular order of the steps is shown, this ordering is merely illustrative, and any suitable arrangement of the steps may be utilized without departing from the scope of the embodiments herein. Even further, the illustrated steps may be modified in any suitable manner in accordance with the scope of the present claims. 
     Accordingly, the magnetically-actuated variable-length connecting rod devices and methods for controlling the same discussed herein can yield powertrain performance and efficiency improvements by adjusting engine displacement to dynamically suit engine load. Under low-load conditions, such as idling, the connecting rod can lengthen, raising the compression ratio and improving efficiency, which results in fuel savings. Under high-load conditions, the connecting rod can shorten, lowering the compression ratio and improving driving performance, such as by allowing increased boost from a turbocharger with a reduced likelihood of engine knock. Because the variable-length connecting rod device discussed herein is magnetically-actuated, the device can have minimal packaging compromises compared to conventional variable displacement engine approaches. For aside from a solenoid wrapped around each engine cylinder, all other components can be contained within the existing engine cylinder space. Moreover, the magnetically-actuated variable-length connecting rod device discussed herein can improve energy efficiency over conventional variable displacement engine approaches, since only a brief pulse of electric current is sufficient for actuating the magnetic components that unlock the connecting rod components, as described above, and the connecting rod extends or contracts using only inertia from the crankshaft. 
     The foregoing description has been directed to certain embodiments of the present disclosure. It will be apparent, however, that other variations and modifications may be made to the described embodiments, with the attainment of some or all of their advantages. Accordingly, this description is to be taken only by way of example and not to otherwise limit the scope of the embodiments herein. Therefore, it is the object of the appended claims to cover all such variations and modifications as come within the true spirit and scope of the embodiments herein.