US20120034115A1 - Method of operating a pump/motor - Google Patents
Method of operating a pump/motor Download PDFInfo
- Publication number
- US20120034115A1 US20120034115A1 US12/851,959 US85195910A US2012034115A1 US 20120034115 A1 US20120034115 A1 US 20120034115A1 US 85195910 A US85195910 A US 85195910A US 2012034115 A1 US2012034115 A1 US 2012034115A1
- Authority
- US
- United States
- Prior art keywords
- piston
- cylinder
- center position
- dead center
- group
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims abstract description 66
- 239000012530 fluid Substances 0.000 claims abstract description 88
- 238000005086 pumping Methods 0.000 claims abstract description 31
- 230000000712 assembly Effects 0.000 claims description 120
- 238000000429 assembly Methods 0.000 claims description 120
- 238000006073 displacement reaction Methods 0.000 description 15
- 238000006243 chemical reaction Methods 0.000 description 7
- 230000005540 biological transmission Effects 0.000 description 5
- 238000004891 communication Methods 0.000 description 4
- 230000002706 hydrostatic effect Effects 0.000 description 4
- 230000033001 locomotion Effects 0.000 description 4
- 238000010276 construction Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
- F03C—POSITIVE-DISPLACEMENT ENGINES DRIVEN BY LIQUIDS
- F03C1/00—Reciprocating-piston liquid engines
- F03C1/02—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders
- F03C1/06—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis
- F03C1/0678—Control
- F03C1/0681—Control using a valve in a system with several motor chambers, wherein the flow path through the chambers can be changed
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
- F03C—POSITIVE-DISPLACEMENT ENGINES DRIVEN BY LIQUIDS
- F03C1/00—Reciprocating-piston liquid engines
- F03C1/02—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders
- F03C1/04—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinders in star or fan arrangement
- F03C1/0447—Controlling
- F03C1/045—Controlling by using a valve in a system with several pump or motor chambers, wherein the flow path through the chambers can be changed, e.g. series-parallel
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
- F03C—POSITIVE-DISPLACEMENT ENGINES DRIVEN BY LIQUIDS
- F03C1/00—Reciprocating-piston liquid engines
- F03C1/02—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders
- F03C1/06—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis
- F03C1/061—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis having stationary cylinders
- F03C1/0615—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis having stationary cylinders distributing members
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/002—Hydraulic systems to change the pump delivery
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
- F04B53/10—Valves; Arrangement of valves
- F04B53/108—Valves characterised by the material
- F04B53/1082—Valves characterised by the material magnetic
Definitions
- each piston/cylinder assembly 30 of the pump/motor 14 includes a low-pressure valve 46 operable to selectively fluidly communicate the cylinder 38 with the low-pressure manifold 22 .
- the low-pressure valve 46 is seated inside the cylinder 38 , such that the low-pressure valve 46 must be moved in a direction toward the interior of the cylinder 38 to unseat or open the low-pressure valve 46 to fluidly communicate the cylinder 38 with the low-pressure manifold 22 .
- the low-pressure valve 46 is actuated to an unseated position by an electromagnetic coil 48 , and is biased toward a seated position by a biasing element (e.g., a spring; not shown).
- a biasing element e.g., a spring; not shown.
- other actuators and/or biasing elements may be utilized to move the low-pressure valve 46 between the seated and unseated positions.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Reciprocating Pumps (AREA)
Abstract
A method of operating a pump/motor includes pumping working fluid into a high-pressure manifold with a first piston/cylinder assembly while the piston in the first piston/cylinder assembly is displaced from a bottom dead center position to a top dead center position, and transferring working fluid from the high-pressure manifold to the cylinder of a second piston/cylinder assembly to displace the piston of the second piston/cylinder assembly from a top dead center position to a bottom dead center position, thereby imparting torque on a cam and an output shaft, within the same complete revolution of the cam and the output shaft in which working fluid is pumped into the high-pressure manifold by the first piston/cylinder assembly.
Description
- The present invention relates to hydraulic pump/motors, and more particularly to hydraulic pump/motors for use in vehicle transmissions, mobile hydraulic applications, and industrial hydraulic applications.
- Multi-cylinder hydraulic pump/motors are typically utilized in tandem, for example, in a vehicle hydrostatic transmission. A first of the pump/motors is connected to a prime mover (e.g., an engine), while the second pump/motor is connected to the driveline of the vehicle. The first pump/motor is powered by the engine to operate as a pump to supply pressurized hydraulic fluid to the second pump/motor, which operates as a motor to power the driveline. When the second pump/motor is operating as a motor at less than full capacity or displacement (i.e., at low flow fractions), low frequency variations in torque at the output shaft of the second pump/motor often result. Such variations may lead to lugging of a drive train coupled to the output shaft, or undesirable noise, vibration, and harshness generated by the second pump/motor when operating as a motor.
- The present invention provides, in one aspect, a method of operating a pump/motor in a system including a high-pressure manifold and a low-pressure manifold. The pump/motor includes an output shaft, a plurality of piston/cylinder assemblies, and a cam coupled to the output shaft and disposed between the output shaft and the piston/cylinder assemblies. Each piston/cylinder assembly includes a cylinder and a piston at least partially disposed in the cylinder and engaged with the cam. The method includes displacing the pistons of the respective piston/cylinder assemblies from a bottom dead center position to a top dead center position, and then back to the bottom dead center position, within each revolution of the cam and the output shaft, pumping working fluid into the high-pressure manifold with a first piston/cylinder assembly while the piston in the first piston/cylinder assembly is displaced from the bottom dead center position to the top dead center position, and transferring working fluid from the high-pressure manifold to the cylinder of a second piston/cylinder assembly to displace the piston of the second piston/cylinder assembly from the top dead center position to the bottom dead center position, thereby imparting torque on the cam and the output shaft, within the same complete revolution of the cam and the output shaft in which working fluid is pumped into the high-pressure manifold by the first piston/cylinder assembly.
- The present invention provides, in another aspect, a method of operating a pump/motor in a system including a high-pressure manifold and a low-pressure manifold. The pump/motor includes an output shaft, a plurality of piston/cylinder assemblies, and a cam coupled to the output shaft and disposed between the output shaft and the piston/cylinder assemblies. Each piston/cylinder assembly includes a cylinder and a piston at least partially disposed in the cylinder and engaged with the cam, a first valve selectively fluidly communicating the high-pressure manifold and the cylinder, and a second valve selectively fluidly communicating the low-pressure manifold and the cylinder. The method includes opening the first valve of a first group of piston/cylinder assemblies to at least partially fill each of the cylinders within the first group with high-pressure working fluid, thereby displacing the pistons within the respective cylinders in the first group from a top dead center position to a bottom dead center position, rotating the output shaft and the cam with the pistons in the first group, opening the second valve of a second group of piston/cylinder assemblies, driving each of the pistons within the second group, with the rotating cam, from the bottom dead center position to the top dead center position to at least partially exhaust working fluid from each of the cylinders within the second group to the low-pressure manifold, opening the first valve of a first piston/cylinder assembly not in either of the first and second groups while the respective first valves in the first group are opened, and driving the piston in the first piston/cylinder assembly, with the rotating cam, from the bottom dead center position toward the top dead center position to pump working fluid into the high-pressure manifold while the first valve of the first piston/cylinder assembly is opened.
- The present invention provides, in yet another aspect, a method of operating a pump/motor in a system including a high-pressure manifold and a low-pressure manifold. The pump/motor includes an output shaft, a plurality of piston/cylinder assemblies, and a cam coupled to the output shaft and disposed between the output shaft and the piston/cylinder assemblies. Each piston/cylinder assembly includes a cylinder and a piston at least partially disposed in the cylinder and engaged with the cam, a first valve selectively fluidly communicating the high-pressure manifold and the cylinder, and a second valve selectively fluidly communicating the low-pressure manifold and the cylinder. The method includes opening the first valve of a first group of piston/cylinder assemblies to fluidly communicate the cylinders in the first group with the high-pressure manifold, rotating the output shaft and the cam, thereby displacing the pistons within the respective cylinders in the first group from a bottom dead center position to a top dead center position to pump working fluid in the respective cylinders in the first group into the high-pressure manifold, opening the second valve of a second group of piston/cylinder assemblies, at least partially filling the respective cylinders within the second group with working fluid from the low-pressure manifold, thereby displacing the pistons within the respective cylinders in the second group from the top dead center position to the bottom dead center position, opening the first valve of a first piston/cylinder assembly not in either of the first and second groups, while the respective first valves in the first group are opened, to at least partially fill the cylinder of the first piston/cylinder assembly with high-pressure working fluid, thereby displacing the piston in the first piston/cylinder assembly from the top dead center position to the bottom dead center position, and imparting a torque on the cam and the output shaft with the piston in the first piston/cylinder assembly as the piston in the first piston/cylinder assembly moves from the top dead center position to the bottom dead center position.
- Other features and aspects of the invention will become apparent by consideration of the following detailed description and accompanying drawings.
-
FIG. 1 illustrates a prior-art multi-cylinder hydraulic pump/motor in which the method of the present invention may be implemented. -
FIG. 2 is a schematic of the pump/motor ofFIG. 1 , illustrating a prior-art method of operating the pump/motor. -
FIG. 3 is a schematic of the pump/motor ofFIG. 1 , illustrating another prior-art method of operating the pump/motor. -
FIG. 4 is a schematic of the pump/motor ofFIG. 1 , illustrating a method of operating the pump/motor according to one embodiment of the invention. -
FIG. 5 is a schematic of the pump/motor ofFIG. 1 , illustrating a method of operating the pump/motor according to another embodiment of the invention. -
FIG. 6 is a graph illustrating torque versus cam shaft angle of a pump/motor configured similarly as that shown inFIG. 1 , utilizing the prior-art method of operating the pump/motor shown inFIG. 2 . -
FIG. 7 is a graph illustrating torque versus cam shaft angle of a pump/motor configured similarly as that shown inFIG. 1 , utilizing the method of operating the pump/motor shown inFIG. 4 . -
FIG. 8 is a graph illustrating torque versus cam shaft angle of a pump/motor configured similarly as that shown inFIG. 1 , utilizing the prior-art method of operating the pump/motor shown inFIG. 3 . -
FIG. 9 is a graph illustrating torque versus cam shaft angle of a pump/motor configured similarly as that shown inFIG. 1 , utilizing the method of operating the pump/motor shown inFIG. 5 . - Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.
-
FIG. 1 illustrates asystem 10 including a multi-cylinder hydraulic pump/motor 14 connected to a high-pressure manifold 18 and a low-pressure manifold 22. Both the high-pressure and low-pressure manifolds pressure manifold 18 is maintained at a higher pressure than the working fluid in the low-pressure manifold 22. Although not shown, an accumulator may be fluidly connected to each of themanifolds manifolds - The pump/
motor 14 includes anoutput shaft 26, a plurality of piston/cylinder assemblies 30, and acam 34 coupled to theoutput shaft 26 and disposed between theoutput shaft 26 and the piston/cylinder assemblies 30. Each piston/cylinder assembly 30 includes acylinder 38 and apiston 42 at least partially disposed in thecylinder 38 and engaged with thecam 34. In operation, each of thepistons 42 is displaced from a bottom dead center position (seepiston 42 b) to a top dead center position (seepiston 42 a), and then back to the bottom dead center position, within each revolution of thecam 34 and theoutput shaft 26. Although only two piston/cylinder assemblies 30 are shown inFIG. 1 , the pump/motor 14 may include any of a number of different piston/cylinder assemblies 30 (e.g., 24; seeFIGS. 2-5 ) - With reference to
FIG. 1 , each piston/cylinder assembly 30 of the pump/motor 14 includes a low-pressure valve 46 operable to selectively fluidly communicate thecylinder 38 with the low-pressure manifold 22. The low-pressure valve 46 is seated inside thecylinder 38, such that the low-pressure valve 46 must be moved in a direction toward the interior of thecylinder 38 to unseat or open the low-pressure valve 46 to fluidly communicate thecylinder 38 with the low-pressure manifold 22. In the illustrated construction of the pump/motor 14, the low-pressure valve 46 is actuated to an unseated position by anelectromagnetic coil 48, and is biased toward a seated position by a biasing element (e.g., a spring; not shown). Alternatively, other actuators and/or biasing elements may be utilized to move the low-pressure valve 46 between the seated and unseated positions. - Each piston/
cylinder assembly 30 of the pump/motor 14 also includes a high-pressure valve 50 operable to selectively fluidly communicate thecylinder 38 with the high-pressure manifold 18. The high-pressure valve 50 is seated outside thecylinder 38, such that the high-pressure valve 50 must be moved in a direction away from thecylinder 38 to unseat or open the high-pressure valve 50 to fluidly communicate thecylinder 38 with the high-pressure manifold 18. In the illustrated construction of the pump/motor 14, the high-pressure valve 50 is actuated to an unseated position by anelectromagnetic coil 54, and is biased toward a seated position by a biasing element (e.g., a spring; not shown). Alternatively, other actuators and/or biasing elements may be utilized to move the high-pressure valve 50 between the seated and unseated positions. - The
system 10 also includes acontroller 58 in communication with each of the actuators (i.e., theelectromagnetic coils 48, 54) of the low-pressure valves 46 and the high-pressure valves 50 to control the opening and closing of thevalves controller 58 may communicate with each of thecoils pressure valves electrical wires 60. Alternatively, any of a number of different wireless protocols may be employed. Thesystem 10 also includes anencoder 62 in communication with thecontroller 58 to monitor the rotational position of thecam 34 over time (and therefore the rotational speed of thecam 34 and the output shaft 26). Alternatively, other components or devices may be used to permit thecontroller 58 to monitor the rotational position of thecam 34 during operation of thesystem 10. - The
system 10 may be incorporated, for example, in a vehicle hydrostatic transmission in which theoutput shaft 26 is coupled to a driveline of the vehicle. Such a vehicle hydrostatic transmission would also include a second pump/motor (not shown) driven by a prime mover (e.g., an engine; also not shown). In operation of the hydrostatic transmission, the engine would drive the second pump/motor as a pump to provide high-pressure working fluid to the high-pressure manifold 18, which would be used to operate the pump/motor 14 shown inFIG. 1 as a motor to drive or deliver torque to the vehicle driveline. - To deliver or impart torque to the
cam 34 and theoutput shaft 26, each of the piston/cylinder assemblies 30 in the pump/motor 14 is actuated through a cycle in which thepistons 42 of therespective assemblies 30 are displaced from the top dead center position to the bottom dead center position, and then back to the top dead center position. Particularly, starting at the top dead center position of thepiston 42 a, thecontroller 58 activates thecoil 54 of the high-pressure valve 50 to open thevalve 50 for a period of time to fluidly communicate thecylinder 38 and the high-pressure manifold 18, causing a transfer of high-pressure working fluid from the high-pressure manifold 18 to the substantiallyempty cylinder 38 in which thepiston 42 a is located. The transfer of high-pressure working fluid into thecylinder 38 subsequently displaces thepiston 42 a toward thecam 34. Thecam 34 includes aninclined cam surface 66 which converts the axial motion of thepiston 42 a to rotational motion of thecam 34 and theoutput shaft 26. As a result, the linear force exerted on thepiston 42 a by the high-pressure working fluid transferred into thecylinder 38 is converted to torque on thecam 34 and theoutput shaft 26 about arotational axis 70 of thecam 34 and theoutput shaft 26. - The
piston 42 a will continue to impart torque to thecam 34 and theoutput shaft 26 until thepiston 42 a reaches its bottom dead center position (i.e., the position of thepiston 42 b inFIG. 1 ). For a configuration of the pump/motor 14 including a plurality of piston/cylinder assemblies 30 oriented symmetrically about therotational axis 70, this portion of the cycle (i.e., thepiston 42 moving from the top dead center position to the bottom dead center position) may be initiated sequentially such that at least one-half of the piston/cylinder assemblies 30 in the pump/motor 14 are imparting torque to thecam 34 and the output shaft at 26 any given time throughout a complete revolution of thecam 34 and theoutput shaft 26. - Shortly before the
piston 42 a reaches the bottom dead center position, thecontroller 58 closes the high-pressure valve 50 to cease fluid communication between thecylinder 38 and the high-pressure manifold 18. Continued movement of thepiston 42 a toward the bottom dead center position reduces the pressure in thecylinder 38 until it is substantially equal to the pressure of the working fluid in the low-pressure manifold 22. After a brief period of time during which thepiston 42 a dwells near the bottom dead center position, thecontroller 58 then activates thecoil 48 of the low-pressure valve 46 to open thevalve 46 to fluidly communicate thecylinder 38 and the low-pressure manifold 22. The rotatingcam 34 then drives the piston 42 (e.g.,piston 42 b) from the bottom dead center position to the top dead center position, during which time the working fluid in thecylinder 38 is exhausted past the low-pressure valve 46 and into the low-pressure manifold 22. Thecontroller 58 closes the low-pressure valve 46 shortly before thepiston 42 b reaches the top dead center position to permit the remaining working fluid in thecylinder 38 to be pressurized to a value that is substantially equal to the pressure of the working fluid in the high-pressure manifold 18 to permit the high-pressure valve 50 to open for the subsequent cycle of transferring high-pressure working fluid into thecylinder 38. - This process is schematically illustrated in
FIG. 2 , in which aprofile 74 of thecam surface 66 is shown in two dimensions relative to the piston/cylinder assemblies 30 of the pump/motor 14. The span of thecam profile 74 is representative of a single complete revolution of thecam 34 in which eachpiston 42 is displaced from the top dead center position (TDC”) to the bottom dead center position (“BDC”), and then back to the top dead center position. Arrow A indicates the direction of movement of thecam profile 74 relative to the respective piston/cylinder assemblies 30, which remain stationary on the page ofFIG. 2 as thecam profile 74 passes underneath the piston/cylinder assemblies 30. As such, thepistons 42 of the respective piston/cylinder assemblies 30 engaged with the left side of thecam profile 74 from the point of view ofFIG. 2 are displaced from the bottom dead center position to the top dead center position, while thepistons 42 of the respective piston/cylinder assemblies 30 engaged with the right side of thecam profile 74 from the point of view ofFIG. 2 are displaced from the top dead center position to the bottom dead center position. - The piston/
cylinder assemblies 30 identified with an “M” are those undergoing the cycle described above in which working fluid from the high-pressure manifold 18 is transferred into the piston/cylinder assemblies 30 to perform work on thecam 34 and the output shaft 26 (i.e., by imparting torque to thecam 34 and the output shaft 26), and subsequently exhausted to the low-pressure manifold 22. This cycle is hereinafter referred to as “motoring,” in which the pump/motor 14 is used as a motor to power the vehicle driveline or other mechanism. The piston/cylinder assemblies 30 used in the motoring cycle (i.e., those marked with an “M”) that are further identified with an “X” as “active” are those in which high-pressure working fluid from the high-pressure manifold 18 is being injected or transferred as described above to impart torque to thecam 34 and theoutput shaft 26 to rotate thecam 34 and theoutput shaft 26. The piston/cylinder assemblies 30 used in the motoring cycle in which an “X” is omitted are those in which thepistons 42 are being driven by thecam 34 to exhaust working fluid to the low-pressure manifold 22 as described above. - As shown in
FIG. 2 , the pump/motor 14 includes 24 piston/cylinder assemblies 30. However, not all 24 of the pump/motor assemblies 30 are shown being used in the motoring cycle. Rather, only 15 of the piston/cylinder assemblies 30 in the pump/motor 14 are being used in the motoring cycle. Those piston/cylinder assemblies 30 that are inactive (i.e., with no “M” or “X” identifier) do not contribute to the work performed on thecam 34 to rotate thecam 34. Rather, therespective valves cylinder assemblies 30 may remain closed such that working fluid is inhibited from entering thecylinders 38 of the inactive piston/cylinder assemblies 30. Consequently, thepiston 42 in the inactive piston/cylinder assemblies 30 would remain stationary within the housing of the pump/motor 14 after being displaced to the top dead center position, and would not reciprocate between the top dead center position and the bottom dead center position. Alternatively, the low-pressure valves 46 of the inactive piston/cylinder assemblies 30 may remain open, such that low-pressure working fluid is allowed to flow into and out of thecylinders 38 of the inactive piston/cylinder assemblies 30 as therespective pistons 42 reciprocate between the top dead center position and the bottom dead center position, without substantially contributing to the work performed on thecam 34 to rotate thecam 34. - Fewer than the total number of available piston/
cylinder assemblies 30 may be utilized at any time when the full capacity or the displacement of the pump/motor 14 (when operating as a motor) is not needed. For example, the pump/motor 14, when operating as a motor, may be operated at less than full displacement when the desired speed of the vehicle driveline (and therefore the speed of thecam 34 and the output shaft 26) is relatively low. To operate the pump/motor 14 at a reduced displacement, a select number of piston/cylinder assemblies 30 in the pump/motor 14 are made inactive. Those inactive piston/cylinder assemblies 30 are interspersed amongst the piston/cylinder assemblies 30 that are motoring. As shown inFIG. 2 , this yields several gaps along thecam profile 74 within which work is not performed on thecam 34 to rotate thecam 34. If enough of the piston/cylinder assemblies 30 are made inactive, the gaps along thecam profile 74 within which work is not performed on thecam 34 to rotate thecam 34 may cause the torque output of theoutput shaft 26 to fluctuate which, in turn, may yield undesirable noise and roughness from the pump/motor 14. - With reference to
FIG. 1 , it should also be understood that the pump/motor 14 may be operated as a pump to recover energy from the vehicle driveline (e.g., to slow the rotation of the driveline). When operating as a pump, theoutput shaft 26 and thecam 34 are driven by the vehicle driveline to displace therespective pistons 42 in the piston/cylinder assemblies 30 from the bottom dead center position to the top dead center position, and then back to the bottom dead center position. - Particularly, starting at the top dead center position of the
piston 42 a, thecontroller 58 activates thecoil 48 of the low-pressure valve 46 to open thevalve 46 for a period of time to fluidly communicate thecylinder 38 and the low-pressure manifold 22, causing a transfer of low-pressure working fluid from the low-pressure manifold 22 to the substantiallyempty cylinder 38 in which thepiston 42 a is located. The transfer of low-pressure working fluid into thecylinder 38 subsequently displaces thepiston 42 a toward thecam 34. As the pressure of the working fluid in the low-pressure manifold 22 is substantially less than the pressure of the working fluid in the high-pressure manifold 18, any torque imparted on thecam 34 by thepiston 42 a as it is displaced from the top dead center position to the bottom dead center position is negligible. - The
piston 42 a will continue to be displaced toward thecam 34 until thepiston 42 a reaches the bottom dead center position (i.e., the position of thepiston 42 b inFIG. 1 ). Shortly before or when thepiston 42 b reaches the bottom dead center position, thecontroller 58 closes the low-pressure valve 46 to cease fluid communication between thecylinder 38 and the low-pressure manifold 22. Thepiston 42 b is then driven by the rotatingcam 34 upward toward the top dead center position until the pressure of the working fluid in thecylinder 38 is increased to a value that is substantially equal to the pressure of the working fluid in the high-pressure manifold 18, after which time thecontroller 58 opens the high-pressure valve 50 to fluidly communicate thecylinder 38 and the high-pressure manifold 18. The resultant high-pressure working fluid in thecylinder 38 is then pumped into the high-pressure manifold 18 for later use by the pump/motor 14 during a motoring cycle. Thecontroller 58 closes the high-pressure valve 50 when a substantial amount of high-pressure working fluid in thecylinder 38 is pumped into the high-pressure manifold 18 and thepiston 42 b is near or at the top dead center position. The pressure of the working fluid left over in thecylinder 38 then decreases to a value that is substantially equal to the pressure of the working fluid in the low-pressure manifold 22 to permit the low-pressure valve 46 to open for the subsequent cycle of transferring low-pressure working fluid into thecylinder 38 for pumping into the high-pressure manifold 18. - This process is schematically illustrated in
FIG. 3 in a similar manner as the schematic ofFIG. 2 . The piston/cylinder assemblies 30 identified with a “P” are those undergoing the cycle described above in which thecam 34 is performing work on thepistons 42 to pump working fluid from the low-pressure manifold 22 into the high-pressure manifold 18. This cycle is hereinafter referred to as “pumping,” in which the pump/motor 14 is used as a pump to recover energy from the vehicle driveline or other mechanism. The piston/cylinder assemblies 30 used in the pumping cycle (i.e., those marked with a “P”) that are further identified with an “X” as “active” are those in which working fluid from the low-pressure manifold 22 is being pumped into the high-pressure manifold 18 as described above for later use by the pump/motor 14 when operating as a motor. The piston/cylinder assemblies 30 used in the pumping cycle in which an “X” is omitted are those in which working fluid from the low-pressure manifold 22 is being introduced into thecylinders 38 as described above when thepiston 42 is moving from the top dead center position to the bottom dead center position. - As shown in
FIG. 3 , the pump/motor 14 includes 24 piston/cylinder assemblies 30. However, not all 24 of the pump/motor assemblies 30 are shown being used in the pumping cycle. Rather, only 6 of the piston/cylinder assemblies 30 in the pump/motor 14 are being used in the pumping cycle. Those piston/cylinder assemblies 30 that are inactive (i.e., with no “P” or “X” identifier) do not contribute to recovering energy from the vehicle driveline. Rather, therespective valves cylinder assemblies 30 may remain closed such that working fluid is inhibited from entering thecylinders 38 of the inactive piston/cylinder assemblies 30. Consequently, thepiston 42 in the inactive piston/cylinder assemblies 30 would remain stationary within the housing of the pump/motor 14 after being displaced to the top dead center position, and would not reciprocate between the top dead center position and the bottom dead center position. Alternatively, the low-pressure valves 46 of the inactive piston/cylinder assemblies 30 may remain open, such that low-pressure working fluid is allowed to flow into and out of thecylinders 38 of the inactive piston/cylinder assemblies 30 as therespective pistons 42 reciprocate between the top dead center position and the bottom dead center position. - Fewer than the total number of available pump/
motor assemblies 30 may be utilized at any time when the full capacity or the displacement of the pump/motor 14 (when operating as a pump) is not needed. For example, the pump/motor 14, when operating as a pump, may be operated at less than full displacement when the speed of the vehicle driveline (and therefore the speed of thecam 34 and the output shaft 26) is relatively low. To operate the pump/motor 14 at a reduced displacement, a select number of piston/cylinder assemblies 30 in the pump/motor 14 are made inactive. Those inactive piston/cylinder assemblies 30 are interspersed amongst the piston/cylinder assemblies 30 that are pumping. As shown inFIG. 3 , this yields several gaps along thecam profile 74 within which a reaction force on thecam 34 is absent. If enough of the piston/cylinder assemblies 30 are made inactive, the gaps along thecam profile 74 within which a reaction force on thecam 34 is absent may cause fluctuation of the output shaft 26 (and therefore lugging of the vehicle driveline) which, in turn, may yield undesirable noise and roughness from the pump/motor 14. -
FIG. 4 is a schematic of the pump/motor 14 ofFIG. 1 , illustrating a method of operating the pump/motor 14 according to one embodiment of the invention in which at least one of the piston/cylinder assemblies 30 in the pump/motor 14 is pumping while a plurality or a group of the piston/cylinder assemblies 30 are motoring during each complete revolution of thecam 34 and theoutput shaft 26. The inventors have found that the method ofFIG. 4 is particularly improved over the prior-art method ofFIG. 2 when fewer than the total number of available piston/cylinder assemblies 30 are utilized when the full capacity or displacement of the pump/motor 14 is not needed.FIG. 4 illustrates 18 piston/cylinder assemblies 30 motoring and 3 piston/cylinder assemblies 30 pumping during each complete revolution of thecam 34 and theoutput shaft 26, yielding a net displacement of 15 piston/cylinder assemblies 30 (the same number of motoring pump/motor assemblies 30 in the prior art method ofFIG. 2 ) from a total of 24 total piston/cylinder assemblies 30. Alternatively, the method of operating the pump/motor 14 illustrated inFIG. 4 may use any of a number of different combinations of piston/cylinder assemblies 30 that are motoring or pumping. However, when the pump/motor 14 is being used as a motor, the number of piston/cylinder assemblies 30 that are motoring must exceed the number of piston/cylinder assemblies 30 that are pumping to yield a net motoring effect. - With respect to the particular manner of operation of the pump/motor shown in
FIG. 4 , at least two piston/cylinder assemblies (e.g., theassemblies pressure manifold 18 at some time during each complete revolution of thecam 34 and theoutput shaft 26. Particularly, as the active motoring piston/cylinder assemblies 30 (those identified with an “M” and an “X”) are consuming high-pressure working fluid from the high-pressure manifold 18 to perform work on thecam 34 to rotate thecam 34 and the output shaft 26 (in the direction of arrow A), the active pumping piston/cylinder assemblies 30 (those identified with a “P” and an “X”) are diverting some of that energy from theoutput shaft 26 and the vehicle driveline by pumping high-pressure working fluid back into the high-pressure manifold 18. -
FIGS. 6 and 7 illustrate graphs of torque (measured at the output shaft 26) versus the rotational angle of thecam 34, corresponding with the displacement of one of thepistons 42 of the piston/cylinder assemblies 30 from the top dead center position to the bottom dead center position. As one of ordinary skill in the art would expect, the average torque output T2 of theoutput shaft 26 when using the method ofFIG. 4 is less than the average torque output T1 of theoutput shaft 26 when using the prior-art method ofFIG. 2 because some of the torque imparted to thecam 34 by the active motoring piston/cylinder assemblies 30 is diverted to the active pumping piston/cylinder assemblies 30 to pump high-pressure working fluid into the high-pressure manifold 18. With reference to the particular data underlying the graphs inFIGS. 6 and 7 , the average torque output T2 of theoutput shaft 26 using the method ofFIG. 4 is about 2.3% less than the average torque output T1 of the output shaft using the prior-art method ofFIG. 2 . - However, the inventors have unexpectedly discovered that the method of
FIG. 4 also reduced the range of torque output values measured at theoutput shaft 26. As used herein, the “range” of torque output values measured at theoutput shaft 26 is the difference between the highest torque output value and the lowest torque output value measured at theoutput shaft 26 over a particular amount of rotation of the cam 34 (e.g., one-half a revolution of thecam 34, a complete revolution of thecam 34, etc.). With reference to the particular data underlying the graphs inFIGS. 6 and 7 , the range R2 of torque output values measured at theoutput shaft 26 using the method ofFIG. 4 is about 11% less than the range R1 of torque output values measured at theoutput shaft 26 using the prior-art method ofFIG. 2 . Consequently, in exchange for a relatively small decrease in average torque output at theoutput shaft 26, a relatively large improvement is achieved in reducing the range of torque output values at theoutput shaft 26. The inventors have found that such an improvement in the reduction of the range of torque output values at theoutput shaft 26 also reduces the noise, vibration, and harshness associated with operating the pump/motor 14 as a motor at less than full capacity or displacement. The inventors have also found that the reduction in the fluctuation of the torque output at theoutput shaft 26 improves the capability of the pump/motor 14 when used as a motor to deliver a relatively consistent torque output to the vehicle drivetrain at relatively low rotational speeds. -
FIG. 5 is a schematic of the pump/motor 14 ofFIG. 1 , illustrating a method of operating the pump/motor 14 according to another embodiment of the invention in which at least one of the piston/cylinder assemblies 30 in the pump/motor 14 is motoring while a plurality or a group of the piston/cylinder assemblies 30 are pumping during each complete revolution of thecam 34 and theoutput shaft 26. The inventors have found that the method ofFIG. 5 is particularly improved over the prior-art method ofFIG. 3 when fewer than the total number of available pump/motor assemblies 30 are utilized when the full capacity or displacement of the pump/motor 14 is not needed.FIG. 5 illustrates 9 piston/cylinder assemblies 30 pumping and 3 piston/cylinder assemblies 30 motoring during each complete revolution of thecam 34 and theoutput shaft 26, yielding a net displacement of 6 piston/cylinder assemblies 30 that are pumping (the same number of pumping piston/cylinder assemblies 30 in the prior art method ofFIG. 3 ) from a total of 24 piston/cylinder assemblies. Alternatively, the method of operating the pump/motor 14 illustrated inFIG. 5 may use any of a number of different combinations of piston/cylinder assemblies 30 that are motoring or pumping. However, when the pump/motor 14 is being used as a pump, the number of piston/cylinder assemblies 30 that are pumping must exceed the number of piston/cylinder assemblies 30 that are motoring to yield a net pumping effect. - With respect to the particular manner of operation of the pump/
motor 14 shown inFIG. 5 , at least two piston/cylinder assemblies 30 (e.g., theassemblies pressure manifold 18 at some time during each complete revolution of thecam 34 and theoutput shaft 26. Particularly, as the active pumping piston/cylinder assemblies 30 (those identified with a “P” and an “X”) are pumping high-pressure working fluid into the high-pressure manifold 18 for later use by the pump/motor 14 when operating as a motor, the active motoring piston/cylinder assemblies 30 (those identified with an “M” and an “X”) are consuming some of the high-pressure working fluid from the high-pressure manifold 18 to impart torque to thecam 34 and theoutput shaft 26. -
FIGS. 8 and 9 illustrate graphs of torque (measured at the output shaft 26) versus the rotational angle of thecam 34, corresponding with the displacement of one of thepistons 42 of the piston/cylinder assemblies 30 from the top dead center position to the bottom dead center position, and then back to the top dead center position, using the prior-art method ofFIG. 3 and the method ofFIG. 5 , respectively. Particularly, the waveforms having negative torque values relate to the individual piston/cylinder assemblies 30 that are pumping, while the waveforms having positive torque values relate to the individual piston/cylinder assemblies 30 that are motoring. - The inventors have unexpectedly discovered that the method of
FIG. 5 reduces the range of reaction torque values measured at theoutput shaft 26. With reference to the particular data underlying the graphs inFIGS. 8 and 9 , the range R4 of reaction torque values measured at theoutput shaft 26 using the method ofFIG. 5 is about 75% less than the range R3 of reaction torque values measured at theoutput shaft 26 using the prior-art method ofFIG. 3 . The inventors have found that such an improvement in the reduction of the range of reaction torque values at theoutput shaft 26 increases the consistency of the flow rate of the working fluid output from the pump/motor 14 when operating as a pump. The inventors have also found that this improvement n the reduction of the range of reaction torque values at theoutput shaft 26 reduces the noise, vibration, and harshness associated with operating the pump/motor 14 as a pump at less than full capacity or displacement. - Various features of the invention are set forth in the following claims.
Claims (20)
1. A method of operating a pump/motor in a system including a high-pressure manifold and a low-pressure manifold, the pump/motor including an output shaft, a plurality of piston/cylinder assemblies, and a cam coupled to the output shaft and disposed between the output shaft and the piston/cylinder assemblies, each piston/cylinder assembly including a cylinder and a piston at least partially disposed in the cylinder and engaged with the cam, the method comprising:
displacing the pistons of the respective piston/cylinder assemblies from a bottom dead center position to a top dead center position, and then back to the bottom dead center position, within each revolution of the cam and the output shaft;
pumping working fluid into the high-pressure manifold with a first piston/cylinder assembly while the piston in the first piston/cylinder assembly is displaced from the bottom dead center position to the top dead center position; and
transferring working fluid from the high-pressure manifold to the cylinder of a second piston/cylinder assembly to displace the piston of the second piston/cylinder assembly from the top dead center position to the bottom dead center position, thereby imparting torque on the cam and the output shaft, within the same complete revolution of the cam and the output shaft in which working fluid is pumped into the high-pressure manifold by the first piston/cylinder assembly.
2. The method of claim 1 , wherein the second piston/cylinder assembly is included in a group of piston/cylinder assemblies from which the first piston/cylinder assembly is excluded, and wherein the method further includes transferring working fluid from the high-pressure manifold to each of the cylinders of the group to displace the respective pistons in the group from the top dead center position to the bottom dead center position within the same complete revolution of the cam and the output shaft in which working fluid is pumped into the high-pressure manifold by the first piston/cylinder assembly.
3. The method of claim 2 , wherein transferring working fluid from the high-pressure manifold to each of the cylinders of the group includes opening a valve in each of the piston/cylinder assemblies of the group to fluidly communicate the respective cylinders of the group with the high-pressure manifold.
4. The method of claim 3 , further comprising exhausting working fluid to the low-pressure manifold with each of the piston/cylinder assemblies of the group when the pistons in the group are displaced from the bottom dead center position to the top dead center position within the same complete revolution of the cam and the output shaft in which working fluid is pumped into the high-pressure manifold by the first piston/cylinder assembly.
5. The method of claim 4 , wherein exhausting working fluid to the low-pressure manifold includes opening a second valve in each of the piston/cylinder assemblies of the group to fluidly communicate the respective cylinders of the group with the low-pressure manifold.
6. The method of claim 5 , further comprising driving each of the pistons of the group with the rotating cam from the bottom dead center position to the top dead center position while the second valve is open to exhaust working fluid from the respective cylinders of the group to the low-pressure manifold.
7. The method of claim 2 , further comprising at least partially filling the cylinder of a third piston/cylinder assembly excluded from the group with working fluid from the low-pressure manifold, thereby displacing the piston in the third piston/cylinder assembly from the top dead center position to the bottom dead center position, within the same complete revolution of the cam and the output shaft in which working fluid is pumped into the high-pressure manifold by the first piston/cylinder assembly.
8. The method of claim 7 , wherein at least partially filling the cylinder of the third piston/cylinder assembly with working fluid from the low-pressure manifold includes opening a valve in the third piston/cylinder assembly to fluidly communicate the cylinder of the third piston/cylinder assembly with the low-pressure manifold.
9. The method of claim 1 , wherein the first piston/cylinder assembly is included in a group of piston/cylinder assemblies from which the second piston/cylinder assembly is excluded, and wherein the method further includes pumping working fluid into the high-pressure manifold with each of the assemblies in the group within the same complete revolution of the cam and the output shaft in which working fluid is transferred from the high-pressure manifold to the second piston/cylinder assembly.
10. The method of claim 9 , wherein pumping working fluid into the high-pressure manifold with each of the piston/cylinder assemblies of the group includes opening a valve in each of the piston/cylinder assemblies of the group to fluidly communicate the respective cylinders of the group with the high-pressure manifold.
11. The method of claim 10 , further comprising driving each of the pistons of the group with the rotating cam from the bottom dead center position to the top dead center position while the valve is open to pump working fluid from the respective cylinders of the group to the high-pressure manifold.
12. The method of claim 10 , further comprising at least partially filling the respective cylinders of the group with low-pressure working fluid from the low-pressure manifold when the pistons in the group are displaced from the top dead center position to the bottom dead center position.
13. The method of claim 12 , wherein at least partially filling the respective cylinders of the group with low-pressure working fluid includes opening a second valve in each of the piston/cylinder assemblies of the group to fluidly communicate the respective cylinders of the group with the low-pressure manifold.
14. The method of claim 10 , further comprising exhausting low-pressure working fluid from the cylinder of a third piston/cylinder assembly excluded from the group to the low-pressure manifold when the piston of the third piston/cylinder assembly is displaced from the bottom dead center position to the top dead center position within the same complete revolution of the cam and the output shaft in which working fluid is transferred from the high-pressure manifold to the second piston/cylinder assembly.
15. The method of claim 14 , wherein exhausting low-pressure working fluid from the cylinder of the third piston/cylinder assembly includes
opening a second valve in the third piston/cylinder assembly to fluidly communicate the cylinder of the third piston/cylinder assembly with the low-pressure manifold, and
driving the piston of the third piston/cylinder assembly with the rotating cam from the bottom dead center position to the top dead center position while the second valve is open to exhaust working fluid from the cylinder of the third piston/cylinder assembly to the low-pressure manifold.
16. A method of operating a pump/motor in a system including a high-pressure manifold and a low-pressure manifold, the pump/motor including an output shaft, a plurality of piston/cylinder assemblies, and a cam coupled to the output shaft and disposed between the output shaft and the piston/cylinder assemblies, each piston/cylinder assembly including a cylinder and a piston at least partially disposed in the cylinder and engaged with the cam, a first valve selectively fluidly communicating the high-pressure manifold and the cylinder, and a second valve selectively fluidly communicating the low-pressure manifold and the cylinder, the method comprising:
opening the first valve of a first group of piston/cylinder assemblies to at least partially fill each of the cylinders within the first group with high-pressure working fluid, thereby displacing the pistons within the respective cylinders in the first group from a top dead center position to a bottom dead center position;
rotating the output shaft and the cam with the pistons in the first group;
opening the second valve of a second group of piston/cylinder assemblies;
driving each of the pistons within the second group, with the rotating cam, from the bottom dead center position to the top dead center position to at least partially exhaust working fluid from each of the cylinders within the second group to the low-pressure manifold;
opening the first valve of a first piston/cylinder assembly not in either of the first and second groups while the respective first valves in the first group are opened; and
driving the piston in the first piston/cylinder assembly, with the rotating cam, from the bottom dead center position toward the top dead center position to pump working fluid into the high-pressure manifold while the first valve of the first piston/cylinder assembly is opened.
17. The method of claim 16 , wherein driving the piston in the first piston/cylinder assembly, with the rotating cam, from the bottom dead center position toward the top dead center position includes pumping working fluid from the cylinder of the first piston/cylinder assembly, through the first valve of the piston/cylinder assembly, and into the high-pressure manifold.
18. The method of claim 16 , wherein the piston/cylinder assemblies are arranged substantially symmetrically about a longitudinal axis of the pump/motor, wherein rotating the output shaft and the cam with the pistons in the first group includes rotating the output shaft and the cam about the longitudinal axis, and wherein opening the first valve of the first piston/cylinder assembly occurs within the same complete revolution of the output shaft and the cam about the longitudinal axis as opening the first valve of the first group of piston/cylinder assemblies.
19. A method of operating a pump/motor in a system including a high-pressure manifold and a low-pressure manifold, the pump/motor including an output shaft, a plurality of piston/cylinder assemblies, and a cam coupled to the output shaft and disposed between the output shaft and the piston/cylinder assemblies, each piston/cylinder assembly including a cylinder and a piston at least partially disposed in the cylinder and engaged with the cam, a first valve selectively fluidly communicating the high-pressure manifold and the cylinder, and a second valve selectively fluidly communicating the low-pressure manifold and the cylinder, the method comprising:
opening the first valve of a first group of piston/cylinder assemblies to fluidly communicate the cylinders in the first group with the high-pressure manifold;
rotating the output shaft and the cam, thereby displacing the pistons within the respective cylinders in the first group from a bottom dead center position to a top dead center position to pump working fluid in the respective cylinders in the first group into the high-pressure manifold;
opening the second valve of a second group of piston/cylinder assemblies;
at least partially filling the respective cylinders within the second group with working fluid from the low-pressure manifold, thereby displacing the pistons within the respective cylinders in the second group from the top dead center position to the bottom dead center position;
opening the first valve of a first piston/cylinder assembly not in either of the first and second groups, while the respective first valves in the first group are opened, to at least partially fill the cylinder of the first piston/cylinder assembly with high-pressure working fluid, thereby displacing the piston in the first piston/cylinder assembly from the top dead center position to the bottom dead center position; and
imparting a torque on the cam and the output shaft with the piston in the first piston/cylinder assembly as the piston in the first piston/cylinder assembly moves from the top dead center position to the bottom dead center position.
20. The method of claim 19 , wherein the piston/cylinder assemblies are arranged substantially symmetrically about a longitudinal axis of the pump/motor, wherein rotating the output shaft and the cam includes rotating the output shaft and the cam about the longitudinal axis, and wherein opening the first valve of the first piston/cylinder assembly occurs within the same complete revolution of the output shaft and the cam about the longitudinal axis as opening the first valve of the first group of piston/cylinder assemblies.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/851,959 US20120034115A1 (en) | 2010-08-06 | 2010-08-06 | Method of operating a pump/motor |
PCT/US2011/046187 WO2012018758A2 (en) | 2010-08-06 | 2011-08-02 | Method of operating a pump/motor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/851,959 US20120034115A1 (en) | 2010-08-06 | 2010-08-06 | Method of operating a pump/motor |
Publications (1)
Publication Number | Publication Date |
---|---|
US20120034115A1 true US20120034115A1 (en) | 2012-02-09 |
Family
ID=44629753
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/851,959 Abandoned US20120034115A1 (en) | 2010-08-06 | 2010-08-06 | Method of operating a pump/motor |
Country Status (2)
Country | Link |
---|---|
US (1) | US20120034115A1 (en) |
WO (1) | WO2012018758A2 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20110031422A1 (en) * | 2009-08-04 | 2011-02-10 | Alejandro Lopez Pamplona | Valve-controlled positive-displacement machine |
EP4048902A4 (en) * | 2019-10-25 | 2023-12-20 | Tonand Inc. | Cylinder on demand hydraulic device |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1255278A (en) * | 1915-12-27 | 1918-02-05 | Robert G Battin | Air compressor or motor. |
US2030759A (en) * | 1934-01-09 | 1936-02-11 | Neal Bob | Compressor unit |
US4671226A (en) * | 1978-11-02 | 1987-06-09 | Mtu-Friedrichshafen Gmbh | Supercharged multi-cylinder four-cycle diesel engine |
US20060039795A1 (en) * | 2002-09-12 | 2006-02-23 | Stein Uwe B | Fluid-working machine and operating method |
US7121190B2 (en) * | 2003-09-26 | 2006-10-17 | Nippon Soken, Inc. | Fluid machine for gas compression refrigerating system |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3441966A1 (en) * | 1984-11-16 | 1986-05-28 | G. Düsterloh GmbH, 4322 Sprockhövel | CONTROL FOR A HYDROSTATIC PISTON ENGINE |
JPH10311421A (en) * | 1997-05-12 | 1998-11-24 | Honda Motor Co Ltd | Vehicular hydraulic continuously variable transmission |
US6681571B2 (en) * | 2001-12-13 | 2004-01-27 | Caterpillar Inc | Digital controlled fluid translating device |
FR2940672B1 (en) * | 2008-12-31 | 2011-01-21 | Poclain Hydraulics Ind | HYDRAULIC MOTOR WITH RADIAL PISTONS AND CYLINDER CONTROL |
-
2010
- 2010-08-06 US US12/851,959 patent/US20120034115A1/en not_active Abandoned
-
2011
- 2011-08-02 WO PCT/US2011/046187 patent/WO2012018758A2/en active Application Filing
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1255278A (en) * | 1915-12-27 | 1918-02-05 | Robert G Battin | Air compressor or motor. |
US2030759A (en) * | 1934-01-09 | 1936-02-11 | Neal Bob | Compressor unit |
US4671226A (en) * | 1978-11-02 | 1987-06-09 | Mtu-Friedrichshafen Gmbh | Supercharged multi-cylinder four-cycle diesel engine |
US20060039795A1 (en) * | 2002-09-12 | 2006-02-23 | Stein Uwe B | Fluid-working machine and operating method |
US7121190B2 (en) * | 2003-09-26 | 2006-10-17 | Nippon Soken, Inc. | Fluid machine for gas compression refrigerating system |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20110031422A1 (en) * | 2009-08-04 | 2011-02-10 | Alejandro Lopez Pamplona | Valve-controlled positive-displacement machine |
EP4048902A4 (en) * | 2019-10-25 | 2023-12-20 | Tonand Inc. | Cylinder on demand hydraulic device |
Also Published As
Publication number | Publication date |
---|---|
WO2012018758A2 (en) | 2012-02-09 |
WO2012018758A3 (en) | 2012-03-22 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6470677B2 (en) | Free piston engine system with direct drive hydraulic output | |
CN101234638A (en) | Hybrid vehicle with engine power cylinder deactivation | |
US8347778B2 (en) | Fluid-working machines | |
US8132868B2 (en) | Hydraulic regenerative braking system for a vehicle | |
US9200648B2 (en) | Fluid control valve systems, fluid systems equipped therewith, and methods of using | |
JP2005517111A (en) | Efficient internal combustion engine valve actuator | |
JP2015520319A (en) | Electromagnetic actuator for reciprocating compressors | |
US11821500B2 (en) | Method and system for harnessing wind energy using a tethered airfoil | |
WO2012162487A2 (en) | Pump having port plate pressure control | |
CN105339646B (en) | High-pressure pump and fuel injection apparatus with high-pressure pump | |
JP2014527134A (en) | Power generation device and operation method of power generation device pump / motor | |
US10801467B2 (en) | Method for controlling torque equilibrium of a hydraulic motor | |
CN111433091A (en) | Method for controlling an internal combustion engine of a hybrid drive train | |
US20120034115A1 (en) | Method of operating a pump/motor | |
CN101892942B (en) | Single piston hydraulic free-piston engine capable of reducing pumping flow pulsation | |
CN105257357B (en) | The automatically controlled quick valve valve variable timing of bimorph and valve variable lift device and control method | |
CN1280647A (en) | Pendulum piston motor | |
CN104564584B (en) | The machine of driving unit and the fast turn-around with this driving unit | |
CN111005854A (en) | Air compressor | |
CN101994538B (en) | Driving mechanism for engine brake | |
US20140271244A1 (en) | Radial hydraulic motor for a hydraulic hybrid vehicle | |
CN103998727A (en) | System and method for engine valve lift strategy | |
JP2022055018A (en) | Fluid machine and method for driving fluid machine | |
CN102966506B (en) | There is the piston pump of cam-actuated valve | |
CN106065859A (en) | Hydrostatic piston machine |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: ROBERT BOSCH GMBH, GERMANY Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:COWAN, RON;BASELEY, SIMON J.;REEL/FRAME:024802/0205 Effective date: 20100802 Owner name: ROBERT BOSCH LLC, ILLINOIS Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:COWAN, RON;BASELEY, SIMON J.;REEL/FRAME:024802/0205 Effective date: 20100802 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |