Patent Publication Number: US-10788060-B2

Title: Cylinder occupying structure

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to mechanical devices used to perform work, and more particularly to hydraulic and combustion cylinders. 
     BACKGROUND OF THE INVENTION 
     A wide variety of devices utilize cylinders to perform mechanical functions and produce useful work. A typical internal combustion engine (ICE), for example, employs a number of cylinders in which a fuel-air mixture is compressed and combusted to produce work that is imparted to a respective reciprocating piston. Each piston may be coupled to a crankshaft, with which forces imparted to the pistons can be transmitted, through various intermediate devices, to the wheels of a vehicle to thereby propel the vehicle. 
     Non-ICE engines and other devices may utilize cylinders in producing work. A hydraulic system, for example, may employ a cylinder having a piston operable to push hydraulic fluid in the cylinder, where pressure applied to the hydraulic fluid by the piston can be transmitted to other components in the hydraulic system in accordance with Pascal&#39;s principle. As a specific example, a hydraulic lift may employ two hydraulic cylinders in fluidic communication to obtain a multiplication in output force: an output cylinder used to lift an object such as a vehicle may be configured with a larger area throughout which the output force is distributed so as to multiply the input force applied to an input cylinder having a relatively smaller area throughout which the input force is applied. 
     When configured for use in an ICE, hydraulic system, or in other contexts, a typical cylinder produces output (e.g., power, force) that is proportional to its stroke volume (e.g., the volume through which a piston surface travels) and stroke distance (e.g., the axial distance through which the piston surface travels). Accordingly, previous systems (e.g., gasoline and diesel ICEs) have turned to increased stroke volumes and/or distances to increase cylinder output. Increasing stroke volume and/or distance may stipulate an increase in cylinder dimensions and thus cylinder mass, however, reducing the overall economy of an engine and vehicle in which such enlarged cylinders are used. Other approaches to increasing engine/vehicle economy may include the use of a recovery system. Hydraulic cylinders, for example, may be coupled to a hydraulic or electrical recovery system, though such recovery systems frequently exhibit limited efficiencies (e.g., 20-30%). In the case of a hydraulic recovery system, in which unused mechanical forces may be redirected to pump fluids into a pressure accumulating storage chamber for later cylinder intake, the operating fluid intake may be originally accumulated under low efficiency recycling methods based on pumping against high head accumulators. While pressurized fluid input or cylinder input pressure can be reduced to increase overall hydraulic system efficiency, cylinder output may correspondingly decrease, as in some configurations the output power of a hydraulic cylinder is proportional to the product of effective head pressure and fluid flow. Moreover, the limited efficiency of cylinder-based systems is further compounded when considering the energy expended in producing the fluids provided as input to a cylinder, such as the energy required to accumulate pressurized fluid for hydraulic cylinders, and the energy required to refine and transport combustible fuel for combustion cylinders. 
     In view of the above, there exists a need for a mechanism to increase the output of a cylinder output without altering attributes of the cylinder, such as stroke volume, stroke length, or the volume of the cylinder itself. 
     SUMMARY OF THE INVENTION 
     This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features of essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure. 
     According to embodiments of the present disclosure, a cylinder system is disclosed, the cylinder system comprising a mechanical cylinder including an internal space in which a fluid is introduced, and a piston configured for reciprocating motion in the internal space; and a cylinder occupying structure including an insertion rod, wherein the insertion rod is variably inserted into, and retracted from, the internal space of the cylinder in correspondence with the reciprocating motion of the piston. 
     In another aspect, the insertion rod displaces a portion of the internal space, such that a volume of the internal space occupied by the fluid is less than an intrinsic volume of the internal space. 
     In another aspect, the insertion rod reduces a fluid intake corresponding to a given stroke of the piston. 
     In another aspect, the cylinder system further comprises a controller configured to control the cylinder occupying structure via an electromagnetic actuator. 
     In another aspect, the electromagnetic actuator includes an electrical system configured to supply current to a coil and thereby generate a magnetic field. 
     In another aspect, the magnetic field interacts with a permanent magnet in the insertion rod to variably insert the insertion rod into, or remove the insertion rod from, the internal space of the cylinder. 
     In another aspect, the insertion rod is variably inserted into, and retracted from, the internal space of the cylinder via a mechanical actuator. 
     In another aspect, the mechanical actuator includes a spring that converts kinetic energy of the insertion rod into potential energy of the spring. 
     In another aspect, the insertion rod is inserted into the internal space of the cylinder during an expansion stroke of the cylinder, and the insertion rod is retracted from the internal space of the cylinder during a compression stroke of the cylinder. 
     In another aspect, the cylinder is a hydraulic cylinder, and the fluid is a hydraulic fluid. 
     In another aspect, the cylinder is a combustion cylinder, and the fluid is a combustible fluid. 
     In another aspect, the insertion rod undergoes motion at a substantially same rate and a substantially same direction as the piston. 
     These and other objects, features, and advantages of the present invention will become more readily apparent from the attached drawings and the detailed description of the preferred embodiments, which follow. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The preferred embodiments of the claimed subject matter will hereinafter be described in conjunction with the appended drawings provided to illustrate and not to limit the scope of the claimed subject matter, where like designations denote like elements, and in which: 
         FIG. 1  presents an exemplary system that employs a cylinder-based engine  102  to produce useful work. 
         FIGS. 2A-2B  show respective states of a combustion cylinder including an exemplary electromagnetic implementation of a cylinder occupying structure. 
         FIGS. 3A-3B  show respective states of a combustion cylinder including an exemplary mechanical implementation of a cylinder occupying structure. 
         FIG. 4  shows an exemplary electromagnetic implementation of a cylinder occupying structure for a hydraulic cylinder. 
         FIG. 5  shows an exemplary mechanical implementation of a cylinder occupying structure for a hydraulic cylinder. 
         FIG. 6  shows another exemplary mechanical implementation of a cylinder occupying structure for a combustion cylinder. 
         FIG. 7  shows a flowchart illustrating an exemplary method of using a cylinder occupying structure. 
     
    
    
     It is to be understood that like reference numerals refer to like parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     The following detailed description is merely exemplary in nature and is not intended to limit the described embodiments or the application and uses of the described embodiments. As used herein, the word “exemplary” or “illustrative” means “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” or “illustrative” is not necessarily to be construed as preferred or advantageous over other implementations. All of the implementations described below are exemplary implementations provided to enable persons skilled in the art to make or use the embodiments of the disclosure and are not intended to limit the scope of the disclosure, which is defined by the claims. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. 
     Disclosed is a cylinder occupying structure. An example provides a cylinder system comprising a mechanical cylinder including an internal space in which a fluid is introduced, and a piston configured for reciprocating motion in the internal space, and a cylinder occupying structure including an insertion rod, wherein the insertion rod is variably inserted into, and retracted from, the internal space of the cylinder in correspondence with the reciprocating motion of the piston. 
     The illustration of  FIG. 1  presents an exemplary system  100  that employs a cylinder-based engine  102  to produce useful work. As non-limiting examples, engine  102  may be utilized to propel a vehicle; including but not limited to seafaring vessels, wheeled vehicles, and aircraft; actuate various devices, such as hydraulic lifts, forklift arms, and backhoe arms, among other components of excavating devices and industrial machinery; and/or for any other suitable purpose. The illustration of  FIG. 1  schematically shows the inclusion in engine  102  of one or more cylinders  104 , with which useful work may be derived to perform such functions. 
     In some examples, engine  102  may be an internal combustion engine (ICE) configured produce useful work by combusting fuel in cylinder(s)  104 . Cylinder(s)  104  may be arranged in any suitable configuration (e.g., I-4, V6, V8, V12). While not shown in the illustration of  FIG. 1 , in some examples engine  102  may be assisted by an electrical system comprising an energy source (e.g., battery) and a motor operatively coupled to one or more wheels of a vehicle in which the engine may be implemented. Such a configuration may be referred to as a “hybrid” configuration, and may employ techniques such as regenerative braking to charge the energy source. 
     Cylinder(s)  104  may include pistons that undergo reciprocating motion caused by fuel combustion therein. In some examples, the reciprocating piston motion may be converted to rotational motion of a crankshaft, which may be coupled to one or more vehicle wheels via a transmission to thereby provide vehicle propulsion. In other examples, the reciprocating piston motion may be converted to other components and/or other forms of motion, including but not limited to articulation of an arm of an industrial vehicle (e.g., forklift, backhoe) and linear actuation. To this end, the illustration of  FIG. 1  shows an output  108  produced by engine  102 , which may include the rotational motion, articulation, or actuation described above, or any other suitable output. 
     An intake passage may be pneumatically coupled to engine  102  to provide intake air to the engine, enabling mixing of the air with fuel to thereby form charge air for in-cylinder combustion. To this end, the illustration of  FIG. 1  shows the reception at engine  102  of an input  106 , which may comprise the fuel/air mixture. Input  106  may include any suitable combination of fuels, including but not limited to gasoline, diesel, nitrous oxide, ethanol, and natural gas. An intake throttle may be arranged in the intake passage and configured to variably control the air ingested into engine  102 —e.g., as a function of mass airflow, volume, pressure. The intake passage may include various components, including but not limited to a charge air cooler, a compressor (e.g., of a turbocharger or supercharger), an intake manifold, etc. Respective intake valves may variably control the ingestion of charge air into cylinder(s)  104 . A fuel system may be provided for storing and supplying the fuel(s) supplied to engine  102 . 
     An exhaust passage may be pneumatically coupled to engine  102  to provide a path by which the products of charge air combustion are exhausted from the engine and to the surrounding environment. Various aftertreatment devices may be arranged in the exhaust passage to treat exhaust gasses, including but not limited to a NOx trap, particulate filter, catalyst, etc. For implementations in which engine  102  is boosted via a turbocharger, a turbine may be arranged in the exhaust passage to drive the turbocharger compressor. Respective exhaust valves may variably control the expulsion of exhaust gasses from cylinder(s)  104 . 
     A controller  110  may be operatively coupled to various components in engine  102  for receiving sensor input, actuating devices, and generally effecting operation of the engine. As such, controller  110  may be referred to as an “engine control unit” (ECU). As examples, ECU may receive one or more of the following inputs: throttle position, barometric pressure, transmission operating gear, engine temperature, and engine speed. As described in further detail below, controller  110  may control the operation of a cylinder operation structure that is variably introduced into the internal space of cylinder(s)  104  in accordance with the operating cycle of the cylinder(s). 
     Controller  110  may be implemented in any suitable manner. As an example, controller  110  may include a logic machine and a storage machine holding machine-readable instructions executable by the logic machine to effect the approaches described herein. The logic machine may be implemented as a controller, processor, system-on-a-chip (SoC), etc. The storage machine may be implemented as read-only memory (ROM, such as electronically-erasable-programmable ROM), and may comprise random-access memory (RAM). Controller  110  may include an input/output (I/O) interface for receiving inputs and issuing outputs (e.g., control signals for actuating components). 
     Engine  102  may assume other forms. For example, engine  102  may be configured for hydraulic operation, where cylinder(s)  104  include respective pistons that undergo reciprocating motion to variably compress a hydraulic fluid therein. In this example, input  106  may include a hydraulic fluid that is supplied to cylinder(s)  104 , such as oil, water, and/or any other suitable fluid(s). Output  108  may include rotational motion, articulation, actuation, or any other suitable type of mechanical output. Alternatively or in addition to mechanical output, output  108  may be considered to include hydraulic fluid that is pressurized by cylinder(s)  104 , where the pressure applied by the cylinders may be transmitted to hydraulic fluid in other components that are in at least partial fluidic communication with the cylinders. Such hydraulic output may in turn be utilized to generate mechanical output, as in a hydraulic lift, for example. For implementations in which engine  102  is configured for hydraulic operation, the engine, and/or other elements that may form a hydraulic circuit, may include any suitable combination of hydraulic components, including but not limited to a pump, valve, accumulator, reservoir, filter, etc. In such implementations, controller  110  may be configured to control the operation of hydraulic cylinder(s)  104 , engine  102 , and/or other components of a hydraulic circuit, based on any suitable sensor output(s) (e.g., pressure, valve state, flow rate). 
     To increase cylinder output and avoid the drawbacks described above associated with existing approaches to increasing cylinder output, cylinder(s)  104  include a cylinder occupying structure that is variably inserted in, and removed from, the internal space of the cylinder(s) in which the operative fluid(s) (e.g., hydraulic fluid, combustible fuel) used to produce output are introduced.  FIGS. 2A-2B  show an exemplary electromagnetic implementation of the cylinder occupying structure for a combustion cylinder,  FIGS. 3A-3B  show an exemplary mechanical implementation of the cylinder occupying structure for a combustion cylinder,  FIG. 4  shows an exemplary electromagnetic implementation of the cylinder occupying structure for a hydraulic cylinder,  FIG. 5  shows an exemplary mechanical implementation of the cylinder occupying structure for a hydraulic cylinder, and  FIG. 6  shows an alternative exemplary mechanical implementation of the cylinder occupying structure for a combustion cylinder.  FIGS. 2-6  are not drawn to scale. 
       FIGS. 2A-2B  show respective states of a combustion cylinder  200  including a cylinder occupying structure  202 . In particular,  FIG. 2A  shows a cross-sectional view of cylinder  200  with a piston  204  oriented toward the bottom of its stroke, which may represent the beginning of a compression or exhaust stroke, for example. Piston  204  is coupled to a connecting rod  206 , which may be coupled to another device such as a crankshaft to thereby translate reciprocating motion of the piston to rotational crankshaft motion or another form of motion, which in turn may be used to propel a vehicle, actuate a device, etc. Reciprocating motion of piston  204  may be caused by charge air combustion in an internal space  208  of cylinder  200 . Combustion may be controlled in part by an intake valve  210  actuated via an intake camshaft  212 , which is operable to selectively inject charge air into internal space  208  for compression and ignition therein. A spark or glow plug  214  may be controlled to cause ignition of injected charge air. Combustion products may be exhausted via an exhaust valve  216  actuated via an exhaust camshaft  218 . To draw heat away from cylinder  200  in the course of charge air combustion, and thereby maintain desired operating temperatures and avoid thermal degradation, a coolant jacket  220  is arranged between the inner cylinder wall that defines internal space  208  and the outer cylinder wall that defines the exterior of the cylinder. A suitable coolant, which may comprise any suitable substance(s) such as water, antifreeze, etc., may be circulated through coolant jacket  220  via a cooling system. The cooling system may include a radiator that radiates heated coolant to an exterior environment, for example. 
     As described above, cylinder  200  includes a cylinder occupying structure  202  that is variably inserted into internal space  208  to increase cylinder output and efficiency. In particular, structure  202  includes an insertion rod  222  that is variably inserted into internal space  208  in correspondence with the reciprocating movement of piston  204 . In some examples, insertion rod  222  may be progressively inserted into internal space  208  as piston  204  moves downward through the internal space. When cylinder  200  is configured to operate according to a two-stroke operating cycle, insertion rod  222  may be introduced into internal space  208  during the intake/combustion stroke, for example. When cylinder  200  is configured to operate according to a four-stroke operating cycle, insertion rod  222  may be introduced into internal space  208  during one or both of the intake and power/expansion stroke, for example. However, cylinder  200  may be configured according to any suitable operating cycle, based on which the introduction of insertion rod  222  into internal space  208  may be controlled. Generally, insertion rod  222  may be inserted into internal space  208  as piston  204  moves downward. 
     The illustration of  FIG. 2B  shows cylinder  200  with piston  204  positioned toward the top of internal space  208  and insertion rod  222  correspondingly retracted, which may represent a different stroke or portion of the operating cycle represented in  FIG. 2A . For example,  FIG. 2B  may represent the state of cylinder  200  during a compression (e.g., for a two or four-stroke operating cycle) or exhaust stroke (e.g., for a four-stroke operating cycle). Taken together,  FIGS. 2A-2B  illustrate how insertion rod  222  may be variably inserted in and removed from internal space  208  in correspondence with movement of piston  204  downward and upward, respectively. The correspondence between movement of insertion rod  222  and piston  204  may assume any suitable form. In some examples, the movement of insertion rod  222  and piston  204  may be substantially synchronized, such that the insertion rod is actuated at substantially the same rate and direction as the piston. As piston  204  changes direction—i.e., stops moving upward or downward, and begins moving downward or upward, respectively—so too may insertion rod  222  accordingly change direction. 
     By placing insertion rod  222  in cylinder  200  during operating cycle portions in which a working fluid (e.g., hydraulic fluid, combustible fuel) is introduced into internal space  208 , the volume of the internal space available to be occupied by the fluid is reduced by its partial occupancy by the insertion rod. The intrinsic volume of internal space  208  and cylinder  200  remains unchanged, however. In this way, the fluid mass introduced into cylinder  200  is reduced, without changing other cylinder parameters that affect cylinder output, such as stroke volume, stroke distance, stroke force, and piston surface area. Put another way, insertion rod  222  enables a reduction in the intake requirement of cylinder  200 , and, as a result of its occupancy of internal space  208 , the insertion rod further causes the volume of the internal space that is utilized in a combustion or hydraulic process—the so-called “combustion volume” or “hydraulic volume”- to be less than the intrinsic volume of the internal space itself. The intrinsic volume of cylinder  200  may be considered the volume defined by the inner walls of the cylinder, and in some contexts the volume above the upper surface of piston  204 . 
     As described above,  FIGS. 2A-2B  depict an example electromagnetic implementation of cylinder occupying structure  202 . In this implementation, insertion rod  222  is variably introduced into and removed from internal space  208  via a solenoid-type electromagnetic actuator comprising a coil  224  that is coupled at top and bottom ends to an electrical system  226 . Coil  224  and insertion rod  222  are arranged such that the insertion rod is variably retracted within the internal of the coil, and substantially along the longitudinal axis of the coil.  FIG. 2A  represents how, in a fully or near-fully extended state in which insertion rod  222  extends into a large portion of internal space  208 , the upper end of the insertion rod may remain within one or more wraps of coil  224 , to thereby retain the ability to retract the insertion rod by electrically actuating the coil. Conversely,  FIG. 2B  represents how, in a fully or near-fully retracted state, the majority of the longitudinal extent of insertion rod  222  may be located within the internal space of coil  224 . In this state, the tip of insertion rod  222  may protrude slightly into internal space  208 , though the tip may be located in any suitable position relative to the internal space. Further, in this state an upper end of insertion rod  222  may contact a support  228  ( FIG. 2B ) provided in a housing  230 , in which coil  224  and a portion of the insertion rod are arranged. An insulation barrier  232  is provided between the exterior wall of cylinder  200  and housing  230  to facilitate low-friction movement of insertion rod  222  between the internal space  208  and the housing, and also provide a substantial seal so that fluid injected into the internal space does not leak into the housing. 
     In this implementation, insertion rod  222  includes a magnet  227  (e.g., a permanent magnet) to enable interaction with magnetic fields generated by electrical currents transmitted through coil  224 , and the solenoid-type electromagnetic extension and retraction of the insertion rod. Magnetic field lines produced by coil  224 —specifically the portions thereof within the internal space of the coil below the upper end of the coil and above the lower end of the coil—may be substantially parallel with the direction in which insertion rod  222  extends and retracts. To facilitate the electromagnetic actuation of insertion rod  222  described herein, electrical system  226  may include a current source with which current is selectively provided to coil  224 . Electrical system  226  is operatively coupled to a controller  234 , which may control the electrical system to selectively position insertion rod  222  in accordance with the operating cycle of cylinder  200  as described above, and/or based on any other suitable inputs (e.g., camshaft timing, valve timing, intake or charge air variables, other operating conditions). In some examples, controller  234  may be controller  110  of  FIG. 1 . One or more of coil  224 , electrical system  226 , magnet  227 , and controller  234  may form what is referred to herein as an “electromagnetic actuator”. In some examples, the electromagnetic actuator may be considered a solenoid, where insertion rod  222  acts as a slug translated by the electromagnetic actuator. 
     Other electromagnetic configurations for actuating insertion rod  222  are contemplated. For example, cylinder occupying structure  202  may be configured with an electromagnetic actuator without a permanent magnet included in insertion rod  222 , where electrical current is selectively applied to the electromagnetic actuator to variably generate a magnetic field. Further, in some examples retraction of insertion rod  222  may be assisted, or fully effected, via upward forces imparted to the insertion rod by fluid in internal space  208  that is pressurized by piston  204 . Generally, any suitable electromagnetic mechanism may be used to actuate insertion rod  222 . 
     Cylinder  200  may be configured with other aspects that increase cylinder output. As one example,  FIGS. 2A-2B  show the inclusion of surface features on a surface  236  of piston  204  in the form of a trapezoidal indentation  238 . Surface features may assume any suitable geometry, however, and in other examples may be provided as protrusions extending above surface  236 , rather than indentations. Such surface features may increase the torque force provided by piston  204 , for example. Similarly, the geometry of insertion rod  222  may be configured to achieve various desired characteristics of cylinder  200 . As one example,  FIGS. 2A-2B  show the tip of insertion rod  222  configured with a conical, extruded tip, though the tip and body of the insertion rod may assume any suitable form. 
     An internal surface of the piston may include dents and/or protrusions to increase the shear stress forces during a relative motion of the piston. Further, the internal surface of the piston may include a second lighter density metal to increase a distance between the gravity or weight center and the geometric center of the piston, providing partial advantage in the stroke distance relative to the cylinder internal space volume. 
     The illustration of  FIGS. 3A-3B  show an exemplary mechanical implementation of the cylinder occupying structure for a combustion cylinder  300 . Aspects of cylinder  200  (e.g., valves, spark/glow plug, piston, coolant jacket, insertion rod) are shared by cylinder  300  and are not repeated in the description of  FIGS. 3A-3B . Like cylinder  200 , cylinder  300  includes an insertion rod  302  that is variably inserted into and retracted from an internal space  304  of cylinder  300  in accordance with the operating cycle of the cylinder.  FIG. 3A  shows cylinder  300  in a first stroke or portion of the operating cycle, such as an intake/combustion and/or power/expansion stroke, and  FIG. 3B  shows the cylinder in a second stroke or portion of the operating cycle, such as a compression or exhaust stroke. 
     As opposed to being electromagnetically actuated as in cylinder  200 , insertion rod  302  is mechanically actuated via a spring  306  provided in a housing  308 . Spring may be referred to herein as an “mechanical actuator”. In this implementation, spring  306  may function as a transducer to convert kinetic energy (e.g., linear motion) of insertion rod  302  into potential energy of the spring (e.g., stored as spring compression), and to convert spring potential energy into insertion rod kinetic energy. Such conversion may be carried out cyclically so as to variably position insertion rod  302  into and out of internal space  304  in correspondence with movement of a piston  310 . More specifically,  FIG. 3A  may represent a state in which insertion rod  302  begins to cease moving downward—effected at least in part by expansion of spring  306 —and begins to move upward. Such upward motion may be effected by the initiation of contraction of spring  306 , and also upward forces imparted to insertion rod  302  by fluid in internal space  304 , where the fluid is pressurized via upward movement of piston  310 . Kinetic energy associated with upward motion of insertion rod  302  is converted into potential energy associated with compression of spring  306  as the insertion rod moves upward, until the spring force opposing insertion rod motion reaches substantial equilibrium, at which point the spring may begin to expand and convert its potential energy into kinetic energy and motion of the insertion rod—e.g., as in the state represented in  FIG. 3B . Various aspects of spring  306  may be configured to enable the corresponding motion of insertion rod  302  with piston  310 , such as the spring&#39;s spring constant. 
     The illustration of  FIG. 4  shows an electromagnetic implementation of the cylinder occupying structure for a hydraulic cylinder  400 . Aspects of the electromagnetically actuated cylinder occupying structure of cylinder  200  are shared by cylinder  400  and are not repeated in the description of  FIG. 4 . In cylinder  400 , an insertion rod  402  is variably inserted into and removed from an internal space  403  of the cylinder via interaction between a magnet  404  in the insertion rod and magnetic fields produced by a coil  406 , in which the insertion rod undergoes opposing directions of linear motion. Coil  406  is arranged in a housing  408 , which interfaces with an insulation barrier  409  that enables low-friction movement of insertion rod  402  and substantial sealing between internal space  403  and the housing. Coil  406  is electrically driven by an electrical system  410 , which is coupled to a controller  412  (e.g., controller  110 ). As described above with reference to  FIGS. 2A-2B , other electromagnetic actuators (e.g., those without the use of a magnet in insertion rod  402 ) may be used to drive the insertion rod. 
     The illustration of  FIG. 4  also shows the system including a magnet  407  to create a magnetic field between a positively charged portion of the insertion rod  402  and the magnet  407 . The magnetic field is shown via magnetic field lines. It is to be understood that the mechanical movement of the insertion rod is parallel with the magnetic field lines shown in  FIG. 4 . Therefore, a movement vector of the insertion rod  402  would not cross the magnetic field lines. The coil  406  provides another magnetic field responsible for controlling the reciprocal movement controls, while the coil or magnet  407  provides a field responsible for providing a driving force of the insertion rod  402 . Therefore, in addition to the magnetic field provided by a solenoid, the system would also need to control the frequency of insertion rod movement, and the advancing force or the motion of the insertion rod may be gained from another field provided by magnet  407 . 
     In contrast with cylinders  200  and  300 , the direction in which insertion rod  402  undergoes motion is not aligned with the direction in which a piston  414  of cylinder  400  undergoes reciprocating motion. For example, the travelling direction of insertion rod  402  may be substantially perpendicular to the travelling direction of piston  414 . However, insertion rod  402  provides a similar function to that of insertion rods  222  and  302 : its occupancy in internal space  403  reduces the space that can be occupied by a hydraulic fluid relative to the intrinsic volume of the internal space, in turn reducing the fluid mass input to cylinder  400  and increasing cylinder output without modifying the stroke volume or distance of piston  414 . Movement of insertion rod  402  may be controlled in correspondence with movement of piston  414 . For example, insertion rod  402  may reach its lowest point substantially concurrently as piston  414  reaches its leftmost point (e.g., the bottom of its stroke), and the insertion rod may reach its highest point substantially concurrently as the piston reaches its rightmost (e.g., the top of its stroke). Cylinder  400  may provide any suitable output, which may comprise pressurized hydraulic fluid that is transmitted to any suitable component, such as another hydraulic cylinder or other hydraulic component, or a device that is actuated via the pressurized fluid.  FIG. 4  generally represents this output in the form of a port  416  that is in fluidic communication with internal space  403  of cylinder  400 . 
     The illustration of  FIG. 5  shows a mechanical implementation of the cylinder occupying structure for a hydraulic cylinder  500 . Aspects of the mechanically actuated cylinder occupying structure of cylinder  300 , as well as aspects of cylinder  400 , are shared by cylinder  500  and are not repeated in the description of  FIG. 5 . In this implementation, a spring  502  is coupled to an insertion rod  504  that is variably introduced into and retracted from an internal space  506  of cylinder  500 . As with spring  306  described above, potential energy stored in spring  502  in the form of spring compression may be converted to kinetic energy and linear motion of insertion rod  504  into internal space  506 , and kinetic energy of the insertion rod may be converted into spring potential energy and stored for subsequent insertions of the rod into the internal space. Pressurized hydraulic fluid output may be provided to other components via a port  508 . 
     The illustration of  FIG. 6  shows an alternative mechanical implementation of the cylinder occupying structure for a combustion cylinder  600 . In this implementation, a plurality of rods or blades  602  are variably introduced into and removed from an internal space  604  of cylinder  600 . Movement of blades  602  is synchronized (e.g., speed and direction) with movement of a piston  606  via the blades&#39; attachment to a piston rod  608  through an attachment structure  610  coupled to the piston rod. A housing  612  provides a space in which blades  602  may be retracted during certain strokes or operating cycle portions of cylinder  600 , and an insulating barrier  614  provides an interface between the housing and cylinder to enable low-friction movement of the blades and substantial sealing between the housing and cylinder. Insulating barrier  614  may include a hole for each blade  602 , for example. Blades  602  may be configured in any suitable manner, including but not limited to the forms of rods, flat blades, curved blades, etc., and may have flat or sharp, pointed ends. Further, blades  602  may be positioned on one side of piston rod  608  as shown, but in other implementations may be distributed substantially evenly around the piston rod for balancing purposes. Blades  602  act to displace a portion of internal space  604  that would otherwise be available to a hydraulic or combustible fluid, to thereby reduce the fluid input to cylinder  600  without reducing the intrinsic volume of the internal space or modifying the stroke volume or distance of piston  606 . 
     The cylinder occupying structure and cylinder implementations described herein are provided as examples and are not intended to be limiting in any way. Numerous modifications are within the scope of this disclosure. “Cylinder” as used herein does not require cylindrical geometry, but rather refers to a mechanical device in which reciprocating piston motion is used to produce useful work and output. Non-spherical geometries, such as hemispherical or wedged geometries may be employed, for example. Various cylinder components may be added, removed, or modified, including cylinder head components, valves, etc. Further, alternative insertion rod configurations are contemplated. For example, the insertion rods disclosed herein may enter a cylinder internal space from the bottom, side, or from any other direction, including at oblique angles. Still further, implementations are possible in which both spring-based and electromagnetic actuation is employed to control an insertion rod. In some hydraulic implementations, a hybrid solution may be employed in which fluid is mechanically pumped as well as magnetically advanced against a piston. For example, fluid may be pressed against a piston plunger without using a hydraulic pump during an active press. 
     The cylinder occupying structure implementations described herein may produce various technical effects and advantages. For example, the cylinder occupying structure may reduce the required fluid intake (e.g., fluid mass, fluid volume) into a cylinder (e.g., the required intake to perform a given stroke or travel a given stroke distance), where the required fluid intake is, in some contexts, initially stipulated by piston movement and shape. A reduced fluid intake may be used to maintain a similar stroke force relative to that associated with an initially larger fluid intake. In other examples, the cylinder occupying structure may allow using a similar fluid volume for a larger distance stroke. Further, the cylinder occupying structure may enable the application of a larger force per square inch on a piston&#39;s internal surface. In some examples, one or more insertion rods may add to a piston&#39;s effective surface area to increase force and power output. In some examples, such as those that employ electromagnetic actuation, the cylinder occupying structure may maintain combustion pressure magnitude, by holding an insertion rod steadily in place, with a magnetic field being initiated with fuel combustion. In some examples, the cylinder occupying structure may enable increases stroke distance and piston momentum via progressive rod insertion into a cylinder internal space. In some examples, the cylinder occupying structure may facilitate laminar piston movement with a slower pressure decline. In some examples, the cylinder occupying structure may enable an increase in power input magnitude from a static electric or static magnetic force. In some examples, the cylinder occupying structure may undergo motion parallel to magnetic field lines, without consuming electric power as long as an insertion rod does not cross the magnetic field lines. In some examples, such as those that employ mechanical spring-based actuation, the cylinder occupying structure may enable increased stroke distance, increased momentum, more laminar piston movement with decreased pressure variations, an increase of power input from insertion rod inertia and spring expansion momentum. In hydraulic implementations, an insertion rod may reduce the pressurized hydraulic fluid intake from a pump, as the fluid moved against a piston plunger is larger in mass than the pumped fluid. These and other technical effects may increase the economy of a vehicle in which the cylinder occupying structure is implemented. 
     The illustration of  FIG. 7  shows a flowchart illustrating an exemplary method  700  of using a cylinder occupying structure. The cylinder occupying structure may assume the form of one of insertion rod  222 ,  302 ,  402 ,  504 , and blades  602 , for example. The cylinder occupying structure may be used in conjunction with a hydraulic or combustion cylinder, such as cylinder  200 ,  300 ,  400 ,  500 ,  600 , and/or  600 , for example. Aspects relating to the control of the cylinder occupying structure may be carried out on a suitable controller, such as controller  110 ,  234 , and/or  412 , for example. 
     At  702 , method  700  includes actuating a piston of a cylinder during an expansion stroke. Actuation of the piston during the expansion stroke may include moving the piston in a first direction that increases the portion of the internal space of the cylinder that can be occupied by an operative fluid (e.g., hydraulic fluid, combustible fuel). The expansion stroke may be an intake stroke, an induction stroke, a power stroke, or any other suitable stroke. 
     At  704 , method  700  includes advancing the cylinder occupying structure into the internal space of the cylinder. The cylinder occupying structure may be advanced into the internal space of the cylinder in correspondence with the piston—e.g., in the first direction, during the expansion stroke and/or substantially synchronized with the piston, which may include advancement in the substantially same direction and/or speed as the piston. 
     At  706 , method  700  includes actuating the piston during a compression stroke. Actuation of the piston during the compression stroke may include compressing the fluid occupying the internal space. The compression stroke may be a compression stroke, an exhaust stroke, or any other suitable stroke. The compression stroke may be an immediately subsequent stroke following the expansion stroke, or one or more other strokes may be carried out between the expansion and compression strokes. The piston may be actuated during the compression in a second direction that in some examples may be substantially opposite to the first direction in which the piston is actuated at  702 . 
     At  708 , method  700  includes retracting the cylinder occupying structure from the internal space of the cylinder. The cylinder occupying structure may be retracted from the internal space of the cylinder in correspondence with the piston—e.g., during the compression stroke and/or substantially synchronized with the piston, which may include retraction in the substantially same direction and/or speed as the piston. 
     Method  700  may be repeated throughout operation of the cylinder, at any suitable frequency, interval, duty cycle, etc., which may include continuous operation or may be interrupted (e.g., in response to controller input, operator input). 
     Since many modifications, variations, and changes in detail can be made to the described preferred embodiments of the invention, it is intended that all matters in the foregoing description and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents.