WO2013118180A1 - Fluid working machine with valve actuation - Google Patents

Fluid working machine with valve actuation Download PDF

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Publication number
WO2013118180A1
WO2013118180A1 PCT/JP2012/000864 JP2012000864W WO2013118180A1 WO 2013118180 A1 WO2013118180 A1 WO 2013118180A1 JP 2012000864 W JP2012000864 W JP 2012000864W WO 2013118180 A1 WO2013118180 A1 WO 2013118180A1
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WO
WIPO (PCT)
Prior art keywords
pressure valve
high pressure
low pressure
valve member
low
Prior art date
Application number
PCT/JP2012/000864
Other languages
English (en)
French (fr)
Inventor
Uwe Stein
Fergus Mcintyre
Jens EILERS
Andrius GONESTAS
Original Assignee
Mitsubishi Heavy Industries, Ltd.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Mitsubishi Heavy Industries, Ltd. filed Critical Mitsubishi Heavy Industries, Ltd.
Priority to EP12706116.6A priority Critical patent/EP2839155B1/en
Priority to PCT/JP2012/000864 priority patent/WO2013118180A1/en
Priority to JP2013504996A priority patent/JP5536276B1/ja
Publication of WO2013118180A1 publication Critical patent/WO2013118180A1/en

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    • 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
    • F04B49/06—Control using electricity
    • F04B49/065—Control using electricity and making use of computers
    • 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
    • F04B39/00—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00
    • F04B39/10—Adaptations or arrangements of distribution members

Definitions

  • the invention relates to the field of fluid working machines in which the displacement of each working chamber is selectable on each cycle of working chamber volume by the active control of low and high pressure valves.
  • the invention relates to the control of the actuation of the low and high pressure valves.
  • EP 0494236 developed this concept and introduced an actively controlled high pressure valve which regulates the flow of working fluid between a working chamber and a high pressure manifold, enabling a motor to carry out either an active cycle or an idle cycle and also enabling a fluid working machine to carry out either pumping or motoring cycles.
  • each valve has a respective solenoid which is coupled to a valve member.
  • the HPV is also typically actively controlled although in the case of a pump the HPV can be operated in a solely passive way, for example, it may be a normally closed, pressure openable check valve.
  • active control we include the possibility of a valve being actively opened, actively closed, actively held open or actively held closed.
  • An actively controlled valve may also move passively in some circumstances.
  • a LPV may be actively closed but open passively when the pressure in a cylinder drops below the pressure in the low pressure manifold.
  • Machines of this type have several advantages, including energy efficiency, an ability to rapidly respond to changes in demand, and a compact size. Although these machines have proven highly effective, to further develop them it would be advantageous to further simplify the control mechanism and to further reduce the bulk and complexity of the valve actuator mechanisms.
  • the invention seeks to provide a valve actuation mechanism which is simpler, smaller and/or more reliable than known valve actuation mechanisms for machines of this type.
  • a fluid working machine comprising at least one working chamber of cyclically varying volume, a low pressure fluid line, a high pressure fluid line, a low pressure valve for regulating the flow of fluid between the working chamber and the low pressure fluid line, a high pressure valve for regulating the flow of fluid between the working chamber and the high pressure fluid line, the low and high pressure valves being selectively actuatable on each cycle of working chamber volume to determine the net displacement of working fluid by the working chamber, the low pressure valve comprising a low pressure valve member, the high pressure valve comprising a high pressure valve member, the low pressure valve member and the high pressure valve member being independently movable between open and closed positions, wherein the fluid working machine further comprises an electronically controlled valve actuator coupled to both the low pressure valve member and the high pressure valve member and configured to both cause an opening or closing force to be applied to the low pressure valve member and to cause an opening or closing force to be applied to the high pressure valve member responsive to actuation of the electronically controlled valve actuator.
  • the low pressure valve member and the high pressure valve member are both subjected to valve opening or closing forces arising from actuation of a single electronically controlled valve actuator, rather than opening or closing forces arising from actuation of separate electronically controlled valve actuators for each of the low pressure valve and the high pressure valve.
  • each of the low pressure valve member and the high pressure valve member are independently movable between open and closed positions. Therefore, despite the use of a shared electronically controlled valve actuator, the low and high pressure valve members can be opened or closed at different times, enabling efficient operation of the fluid working machine.
  • the invention simplifies the control arrangements for the low and high pressure valves, improves reliability, reduces bulk by requiring only a single actuator, and reduces cost.
  • the fluid working machine comprises a controller which determines whether the working chamber undergoes an active cycle or idle cycle on each cycle of working chamber volume by determining whether or not to actuate the electronically controlled valve actuator by generating a valve actuation signal.
  • the controller may also regulate the timing of the opening or closing of either or both the low pressure valve and the high pressure valve, for example by selecting the phase of the valve actuation signal relative to cycles of working chamber volume.
  • the fluid working machine typically comprises a rotating shaft coupled to cycles of working chamber volume and a shaft position sensor which measures the position of the rotating shaft to enable the phase of the valve actuation signals relative to cycles of working chamber volume to be controlled.
  • the electronically controlled valve actuator causes said opening or closing forces to be applied concurrently to the low pressure valve member and the high pressure valve member but they open or close at different times in dependence on changes in the pressure in the working chamber and the low and high pressure fluid lines respectively.
  • the electronically controlled valve actuator causes said opening or closing forces to be applied to the low pressure valve member and the high pressure valve member at the same time but they open or close at different times in dependence on changes in the pressure in the working chamber and the low and high pressure fluid lines respectively.
  • actuation of the actuator causes forces to be applied to the respective valve members associated with a working chamber to close the low pressure valve (to move the low pressure valve member to the closed position) and to open the high pressure valve (to move the high pressure valve member to the open position).
  • the low pressure valve will then close straight away.
  • forces may be applied to bias the low pressure valve closed and the high pressure valve open shortly before top dead centre.
  • the low pressure valve closes quickly but the high pressure valve does not open until sufficient pressure has build up in the contracting working chamber.
  • forces may be applied to urge the high pressure valve to close and the low pressure valve to open.
  • the high pressure valve will close quickly but the low pressure valve will open after a delay, only once the pressure in the working chamber is sufficiently low as a result of expansion of the now sealed working chamber.
  • the low pressure valve comprises one or more low pressure valve biasing members (which are typically resilient members) which bias the low pressure valve member to an open position
  • the high pressure valve comprises one or more high pressure valve biasing members (which are typically resilient members) which bias the high pressure valve member to a closed position.
  • the low pressure valve comprises one or more low pressure valve biasing members which bias the low pressure valve member to a closed position
  • the high pressure valve comprises one or more high pressure valve biasing members which bias the high pressure valve member to an open position.
  • the low pressure valve comprises one or more low pressure valve biasing members which bias the low pressure valve member to a closed position
  • the high pressure valve comprises one or more high pressure valve biasing members which bias the high pressure valve member to a closed position.
  • the low pressure valve comprises one or more low pressure valve biasing members which bias the low pressure valve member to an open position
  • the high pressure valve comprises one or more high pressure valve biasing members which bias the high pressure valve member to an open position.
  • opening or closing forces act in the same sense as the net biasing forces applied to the low pressure and high pressure valve by the one or more low pressure and high pressure valve biasing members respectively.
  • the forces caused by the electronically controlled valve actuator oppose the net biasing forces of the one or more low pressure and high pressure valve biasing members.
  • the forces caused by the electronically controlled valve actuator oppose and exceed the net biasing forces applied to the low pressure and high pressure valve members by the one or more low pressure and high pressure valve biasing members.
  • the low pressure valve comprises one or more low pressure valve biasing members which bias the low pressure valve member to an open position
  • the high pressure valve comprises one or more high pressure valve biasing members which biases the high pressure valve member to a closed position
  • said forces caused by the electronically controlled valve actuator oppose the biasing forces of the low pressure and high pressure valve biasing members.
  • the low pressure valve member is biased either to the open position or the closed position by one or more said low pressure biasing members and the high pressure valve member is biased either to the open position or the closed position by one or more said high pressure biasing members, and said opening or closing forces change the sense of the net biasing applied to the low pressure and/or high pressure valve members.
  • one or more of the valve members may not open immediately due to other forces (e.g. forces arising from a pressure difference across the valve member, drag forces arising from the effect of flowing working fluid on the valve member etc.) the combined forces arising from the electronically controlled valve actuator and any resilient biasing urge the low pressure and high pressure valves would cause the low pressure valve and/or high pressure valve to move were it not for any other forces.
  • the electronically controlled valve actuator applies said opening or closing forces to the low pressure valve member and the high pressure valve member. It may be that the electronically controlled valve actuator actuates one or more further actuators which apply said opening or closing forces.
  • the electronically controlled valve actuator comprises an actuated element (for example, an armature) which is moved when the electronically controlled valve actuator is actuated (for example, by a solenoid through which an activation current is passed) and the forces applied to the low pressure valve member and the high pressure valve member are coupled to movement of the actuated element (for example, through a mechanical, pneumatic or hydraulic coupling).
  • an actuated element for example, an armature
  • the electronically controlled valve actuator is a hydraulic or pneumatic or mechanical actuator
  • the low and high pressure valve members are each driven by hydraulic or pneumatic or mechanical actuators respectively which are hydraulically or pneumatically or mechanically coupled as appropriate to the electronically controlled valve actuator.
  • the electronically controlled valve actuator comprises a solenoid and the low pressure valve member and the high pressure valve member are each coupled to a respective armature and both armatures are driven by the same solenoid.
  • the mean current applied to each solenoid may be switched between two values (one of which is typically zero) or may take a range of values depending on a valve actuation signal.
  • the fluid working machine may comprise a magnetic circuit extending through the solenoid and configured to direct magnetic flux through both armatures.
  • the magnetic circuit may be configured to direct magnetic flux through both armatures in series.
  • the magnetic circuit may comprise a major portion which forms the majority of the magnetic circuit and which directs flux between the armatures and a minor portion which extends between the low pressure valve armature and the high pressure valve armature.
  • the magnetic circuit is configured to direct magnetic flux through both armatures in parallel. It may be that the magnetic circuit is configured to increase the reluctance of a magnetic circuit path through one of the low pressure valve armature and the high pressure valve armature when the respective armature moves. This helps to increase the magnetic flux through the other of the low pressure valve armature and the high pressure valve armature.
  • the magnetic circuit comprises an end stop portion which defines the axial limit of movement of a said armature (the low pressure valve armature or the high pressure valve armature) and a protrusion (which can take the form of a step) extending radially towards said armature, axially spaced from the end stop portion, such that when the armature is in an initial position, axially spaced from the end stop portion (e.g.
  • magnetic flux is directed substantially radially between the armature and the protrusion and when the armature is moves towards the end stop portion, magnetic flux is directed between the armature and the protrusion with an axial component which increases as the armature moves axially towards the end stop portion.
  • the magnetic circuit is configured so that when a current is passed through the solenoid, both the low pressure valve armature and the high pressure valve armature are urged towards the solenoid but that movement of the low pressure valve armature and the high pressure valve armature towards the solenoid opens one of the low pressure valve and the high pressure valve and closes the other of the low pressure valve and the high pressure valve.
  • one or more of the magnetic circuit, the low pressure valve armature and the high pressure valve armature comprises a bridge member which directs magnetic flux across an air gap between the magnetic circuit and a respective armature, wherein the bridge member is tapered. It may be that the magnetic circuit passes through at least one said tapered bridging piece, the at least one tapered bridging piece directing magnetic flux across a gap in the magnetic circuit, the at least one tapered bridging piece directing magnetic flux either one or both of a) between a major portion of the magnetic circuit which forms the majority of the magnetic circuit and the low pressure valve armature or the high pressure valve armature and/or b) through a minor portion of the magnetic circuit which extends between the low pressure valve armature and the high pressure valve armature.
  • the or each bridging member serves to minimise the size of any air gaps and therefore reduce reluctance. Bridging members serve to efficiently transmit flux, to divert flux to an extent by focusing or channelling it as desired, and to transmit flux to adjacent magnetic members.
  • the or each bridge member has a narrow tip.
  • the or each bridge member may have a triangular cross section with a first surface parallel to the direction of movement of the armature and a second surface which meets the first surface at an acute angle such that the thickness of the or each bridging member (of which tapered bridging pieces are an example embodiment), decreases towards its tip.
  • the tapered nature of the or each bridging piece means that field lines are less close together/compressed when the armature is in the energised position.
  • the first parallel surface is located directly adjacent an armature, having a relatively small air gap there-between in order to reduce reluctance between the two parts. This consequently reduces the total reluctance of the entire magnetic circuit.
  • the relatively broad base of the bridging taper pieces is spaced by an air gap apart from the respective armature, and when the armature is in the solenoid energised position, serves to increase the latching force.
  • the latching force retains the armature against the minor portion of the magnetic circuit or an end stop (e.g. to hold the low pressure valve armature in a position such that the low pressure valve is closed or to hold the high pressure valve armature in a position such that the high pressure valve is open).
  • the force acting on the respective armature is initially relatively low but increases with displacement of the valve member, as the respective armature moves towards the thicker end of the bridge member, leading to a relatively high mean force acting on the armature and therefore shortening opening or closing times.
  • the use of a triangular cross section, with one surface parallel to the direction of movement of the armature, reduces the need for magnetic flux to pass through air due to the diagonal travel of the magnetic flux/circuit.
  • opening or closing forces are variable responsive to a valve actuation signal and the fluid working machine is configured to vary the valve actuation signal while said opening or closing forces are applied to thereby vary said opening or closing forces, during at least some operations of said valves.
  • Varying the valve actuation signal may take into account working chamber pressure, and/or low pressure manifold pressure, and/or high pressure manifold pressure.
  • the opening or closing forces may be a function (for example, proportional to) the current through a solenoid.
  • the fluid working machine may comprise a controller which varies the mean current during actuation.
  • the opening or closing forces may be reduced during actuation after either or both of the low and high pressure valves has opened or closed (as appropriate).
  • a first signal having a first mean current may be applied to cause either or both of the low and high pressure valves to open or close and then a second signal having a second mean current, which is lower than the first mean current, may be applied.
  • a greater force is required to open or close a valve than to maintain the valve in the opened or closed position.
  • the current may be pulsed and the first and second signals may have the same maximum and minimum current values but different mark to space ratios.
  • the electronically controlled valve actuator comprises a solenoid and a magnetic circuit configured to direct magnetic flux through an armature coupled to the low pressure valve member and an armature coupled to the high pressure valve member, wherein opening or closing of one or both of the low or high pressure valves responsive to actuation of the electronically controlled valve actuator reduces the reluctance of the magnetic circuit due to the movement of either or both said armatures from an initial position to an actuated position.
  • the mean current required to hold said armature or armatures in the actuated position is typically less than the mean current required to move said armature or armatures to the actuated position, due to the low reluctance.
  • the fluid working machine may be configured to make a step change in the valve actuation signal (typically a step change in mean current which functions as the valve actuation signal) whilst said opening or closing forces are applied to the low and high pressure valve members.
  • a step change in the valve actuation signal typically a step change in mean current which functions as the valve actuation signal
  • the valve actuation means may be electronically coupled to one of the low or high pressure valve member to actuate said low or high pressure valve through the other of the low or high pressure valve member.
  • the low pressure valve is a face seating valve.
  • the low pressure valve or the high pressure valve further comprises a pilot valve comprising a pilot valve member, wherein the electronically controlled valve actuator is also coupled to the pilot valve member to apply an opening or closing force to the pilot valve member responsive to actuation of the electronically controlled valve actuator.
  • the or each pilot valve may have a valve seat, or may be a spool valve, for example.
  • the opening or closing force applied to the pilot valve member is typically in the same sense as the opening or closing force applied to said valve which further comprises the pilot valve.
  • a pilot valve we refer to a lower throughput valve which is opened in use before said low pressure valve or high pressure valve to facilitate the opening of said low pressure valve or high pressure valve against a pressure differential. This facilitation by the pilot valve is the removal of the pressure differential across the LPV or HPV, therefore allowing the LPV or HPV to open once the pressure differential has been removed.
  • the pilot valve seat may be integral to the valve member of said low pressure valve or high pressure valve. Pilot valves are disclosed, for example, in EP 2,064,474 (Stein) and EP 2,329,172 (Stein et al.)
  • a pilot valve is useful in applications with particularly high pressure differentials in use (e.g. off-road vehicles, industrial Hydraulic machinery etc.) and is useful for starting from zero speed shaft, when the high pressure valve is not able to open against pressure differential.
  • the or each pilot valve member may be actuated by the same solenoid as the valve member of the valve which comprises the respective pilot valve.
  • low pressure valve and high pressure valve are integrated into a single unit.
  • the electronically controlled valve actuator may be responsive to the presence or absence of a valve actuation signal.
  • the electronically controlled valve actuator may be responsive to the magnitude of a valve actuation signal, or its frequency or (in embodiments where the valve actuation signal can be pulse width modulated), its mark to space ratio.
  • the electronically controlled valve actuator may start to apply said opening or closing forces responsive to a first signal and may stop applying said opening or closing forces responsive to a second signal.
  • the fluid working machine may be a pump.
  • the fluid working machine may be a motor.
  • the fluid working machine may be a pump-motor which is operable as a pump or a motor in alterative operating modes.
  • the fluid working machine may be pneumatic.
  • the fluid working machine may be hydraulic.
  • the invention also extends in a second aspect to a method of controlling a low pressure valve and a high pressure valve associated with a working chamber in a fluid working machine according to the first aspect of the invention, wherein the electronically controlled valve actuator causes an opening or closing force to be applied concurrently to both the low pressure valve member and the high pressure valve member and the low pressure valve member and the high pressure valve member move, as a result of the applied forces, at different times.
  • the electronically controlled valve actuator applies said opening or closing forces directly to the low pressure valve member and the high pressure valve member.
  • the electronically controlled valve actuator may cause said opening or closing force to be applied to both the low pressure valve member and the high pressure valve member at the same time and the low pressure valve member and the high pressure valve member moves, responsive to the applied forces, at different times.
  • Figure 1 is a schematic diagram of a prior art fluid working machine
  • Figure 2 is a schematic diagram of a fluid working machine according to the invention
  • Figure 3 is a schematic diagram of an embodiment of the invention using coupled pistons
  • Figure 4A is a schematic radial cross section of an embodiment of the invention in which both valve members are driven directly by a single solenoid
  • Figure 4B is a schematic radial cross section of an embodiment of the invention in which both valve members are driven directly by a single solenoid
  • Figure 4C is a schematic radial cross section of an embodiment of the invention in which both valve members are driven directly by a single solenoid
  • Figure 5 is a schematic radial cross section through an alternative example embodiment in which both valve members are driven directly by a single solenoid
  • Figure 6 is a cross-section through an example embodiment in which both valve members are driven directly by a single solenoid
  • Figure 7A is a detail of Figure 6
  • Figure 7B is a corresponding detail after opening of
  • Figure 1 is a schematic diagram of an individual working chamber 2 in a fluid-working machine 1.
  • the net throughput of fluid is determined by the active control of electronically controllable valves, in phased relationship to cycles of working chamber volume, to regulate fluid communication between individual working chambers of the machine and fluid manifolds.
  • Individual chambers are selectable by a controller, on a cycle by cycle basis, to either displace a predetermined fixed volume of fluid or to undergo an idle cycle with no net displacement of fluid, thereby enabling the net throughput of the pump to be matched dynamically to demand.
  • An individual working chamber 2 has a volume defined by the interior surface of a cylinder 4 and a piston 6, which is driven from a crankshaft 8 by a crank mechanism 9 and which reciprocates within the cylinder to cyclically vary the volume of the working chamber.
  • a shaft position and speed sensor 10 determines the instantaneous angular position and speed of rotation of the shaft, and transmits shaft position and speed signals to a controller 12, which enables the controller to determine the instantaneous phase of the cycles of each individual working chamber.
  • the controller typically comprises a microprocessor or microcontroller which executes a stored program in use.
  • the working chamber comprises an actively controlled low pressure valve in the form of an electronically controllable face-sealing poppet valve 14, which faces inwards toward the working chamber and is operable to selectively seal off a channel extending from the working chamber to a low pressure manifold 16.
  • the working chamber further comprises a high pressure valve 18.
  • the high pressure valve faces outwards from the working chamber and is operable to seal off a channel extending from the working chamber to a high pressure manifold 20.
  • At least the low pressure valve is actively controlled so that the controller can select whether the low pressure valve is actively closed, or in some embodiments, actively held open, during each cycle of working chamber volume.
  • the high pressure valve is actively controlled and in some embodiments, the high pressure valve is a passively controlled valve, for example, a pressure delivery check valve.
  • the fluid-working machine may be a pump, which carries out pumping cycles, or a motor which carries out motoring cycles, or a pump-motor which can operate as a pump or a motor in alternative operating modes and can thereby carry out pumping or motoring cycles.
  • a full stroke pumping cycle is described in EP 0 361 927.
  • the low pressure valve is open and hydraulic fluid is received from the low pressure manifold.
  • the controller determines whether or not the low pressure valve should be closed. If the low pressure valve is closed, fluid within the working chamber is pressurized and vented to the high pressure valve during the subsequent contraction phase of working chamber volume, so that a pumping cycle occurs and a volume of fluid is displaced to the high pressure manifold.
  • the low pressure valve then opens again at or shortly after top dead centre. If the low pressure valve remains open, fluid within the working chamber is vented back to the low pressure manifold and an idle cycle occurs, in which there is no net displacement of fluid to the high pressure manifold.
  • the low pressure valve will be biased open and will need to be actively closed by the controller if a pumping cycle is selected. In other embodiments, the low pressure valve will be biased closed and will need to be actively held open by the controller if an idle cycle is selected.
  • the high pressure valve may be actively controlled, or may be a passively opening check valve.
  • a full stroke motoring cycle is described in EP 0 494 236.
  • fluid is vented to the low pressure manifold through the low pressure valve.
  • An idle cycle can be selected by the controller in which case the low pressure valve remains open.
  • the low pressure valve is closed before top dead centre, causing pressure to build up within the working chamber as it continues to reduce in volume.
  • the high pressure valve can be opened, typically just after top dead centre, and fluid flows into the working chamber from the high pressure manifold. Shortly before bottom dead centre, the high pressure valve is actively closed, whereupon pressure within the working chamber falls, enabling the low pressure valve to open around or shortly after bottom dead centre.
  • the low pressure valve will be biased open and will need to be actively closed by the controller if a motoring cycle is selected. In other embodiments, the low pressure valve will be biased closed and will need to be actively held open by the controller if an idle cycle is selected.
  • the low pressure valve typically opens passively, but it may open under active control to enable the timing of opening to be carefully controlled. Thus, the low pressure valve may be actively opened, or, if it has been actively held open this active holding open may be stopped.
  • the high pressure valve may be actively or passively opened. Typically, the high pressure valve will be actively opened.
  • the fluid-working controller is also operable to vary the precise phasing of valve timings to create partial stroke pumping and/or partial stroke motoring cycles.
  • the low pressure valve In a partial stroke pumping cycle, the low pressure valve is closed later in the exhaust stroke so that only a part of the maximum stroke volume of the working chamber is displaced into the high pressure manifold. Typically, closure of the low pressure valve is delayed until just before top dead centre.
  • the high pressure valve is closed and the low pressure valve opened part way through the expansion stroke so that the volume of fluid received from the high pressure manifold and thus the net displacement of fluid is less than would otherwise be possible.
  • FIG. 2 is a schematic diagram of a working chamber of a fluid working machine according to the invention.
  • a shared electronically controlled valve actuator 50 is coupled to the valve members (not shown in Figure 2) of both the high and low pressure valves.
  • a shared control signal is transmitted by the controller through control line 52.
  • the shared actuator When the shared actuator is actuated, forces are applied to the valve members of the high and low pressure valves to urge the low pressure valve to close and the high pressure valve to open.
  • the high and low pressure valve members are able to move independently and, although the low pressure valve member will typically start to move shortly after the shared actuator is actuated, there will be a delay before the high pressure valve member can move, while the pressure in the working chamber increases to a level which enables the high pressure valve to open.
  • a first example of a shared actuator arrangement is illustrated in Figure 3.
  • a piston 100 is slidably mounted in a master cylinder 102 and driven by a solenoid operated actuator 104.
  • the solenoid operated actuator is actuated by a shared control signal received through the control line 52, hydraulic fluid is displaced through hydraulic connections 106 to slave cylinders 108, 110 which comprise pistons 112 and 114, which are coupled through valve stems 116, 118 to a low pressure valve member 120 and a high pressure valve member 122 to urge the low pressure valve member towards low pressure valve seat 124 and the high-pressure valve member away from high-pressure valve seat 126.
  • the high-pressure valve member can, and in practice does, move at a different time to the low pressure valve member.
  • a solenoid coil 200 functions as the electronically controlled valve actuator.
  • the solenoid coil is coupled to the low pressure valve member and high pressure valve member (not shown) through a magnetic circuit formed of a first magnetic circuit member 202 (functioning as part of the major portion of the magnetic circuit), and a second magnetic circuit member 204 (functioning as the minor portion of the magnetic circuit) which directs magnetic flux through a low pressure valve armature 206 which is connected to the low pressure valve member (not shown) via a low pressure valve stem 208, and a high pressure valve armature 210 which is connected to the low pressure valve member (not shown) via a high pressure valve stem 212.
  • the low pressure and high pressure valves are configured so that the low pressure valve is closed by axial movement of the low pressure valve armature and valve stem towards the solenoid and the high pressure valve is opened by axial movement of the high pressure valve armature and valve stem towards the solenoid.
  • the items labelled 206 in the Figures are the low pressure valve armature and the items labelled 210 are the high pressure valve armature in this example embodiment, the low and high pressure valve armatures could be interchanged in alternative embodiments.
  • Magnetic circuit members are typically made from steel, and in particular suitable materials include a silicon steel, a silicon core iron, or 430FR which is a ferritic stainless steel.
  • a force acts on both armatures, urging them in an axial direction, towards the solenoid (upwards in Figure 4A). This applies an opening force to the low pressure valve member and a closing force to the high pressure valve member.
  • Figures 4B and 4C illustrate alternative embodiments which work on a corresponding principle.
  • the armatures are urged towards each other.
  • the range of movement of each valve member is governed in one direction by the respective valve seat, and a respective end stop in the other direction.
  • the end stop may engage the valve member, or part of the armature connected to the valve member.
  • Figure 5 illustrates a further embodiment which corresponds in general terms to the embodiment of Figure 4A but the magnetic circuit includes a magnetic connecting portion (functioning as the minor portion of the magnetic circuit) 204, supported by a non-magnetic support member 214, which is adjacent both the low pressure and high pressure valve armatures and includes tapered bridging pieces 216, 217 which have an axial first surface 220 and an angled opposed surface 222.
  • a further bridging piece 218 extends from the magnetic circuit portion adjacent an end stop 224 which defines the maximum axial travel of the high pressure valve armatures towards the solenoid.
  • the armatures move parallel to the axial first surfaces and as a result of the tapered shape of the bridging pieces, the axial force acting on the valve armatures increases as the armatures move towards their 'activated' positions (the positions towards which they are urged responsive to actuation of the electronically controlled valve actuator). This means that a lower current is required to latch (retain) the valve members in a displaced position when they have completed their movement towards the solenoid and the respective valves are open or closed, than is required to start movement of the valve members.
  • the tapered bridge piece 216 does not change the magnetic force with axial displacement of either armature. Its functions are to help to axially align the HPV armature, to provide additional metal within the magnetic circuit flow path (helping to avoid magnetic saturation), and also to reduce the distance the magnetic flux needs to travel (reduced reluctance).
  • the tapered bridging piece 217 and the further bridging piece 218 provide the proportional control aspect of the magnetic circuit.
  • the 'tip' part of these bridging pieces becomes saturated once the solenoid is activated. Once saturated, flux cannot flow through this portion, and thus flows around the saturated region. Magnetically, the saturated portion equates to an air gap, therefore increasing the tendency for flux to find another path around the saturated portion.
  • the total length of the bridging pieces determines the stroke length of each respective armature.
  • the angle of taper of the bridging pieces determines the time to saturation, which can thus be selected. Generally speaking the greater the internal angle between the axial first surface 220 and the angled opposed surface, the longer the time to saturation.
  • the angle of taper of each of the bridging pieces can be manipulated relative to one another in order to change the forces applied to each armature, and thus both the start time, and initial movement characteristics of each armature relative to each other.
  • Figure 6 illustrates an integrated valve arrangement 225 based on the general principle of Figures 4A and 4B.
  • the integrated valve arrangement comprises both the low pressure and high pressure valves, and a cylinder 226 which slidably receives a piston (not shown) to define a working chamber 227 of cyclically varying volume.
  • a piston not shown
  • Corresponding features have corresponding labelling.
  • the low pressure valve armature and valve stem 208 are formed integrally with the low pressure valve member 228 and that the low pressure valve moves axially towards the solenoid to close the low pressure valve by bringing the low pressure valve member into sealing contact with the low pressure valve seat 230.
  • the low pressure valve member is biased to the open position by spring 232 and the force from the solenoid reverses the sense of overall biasing.
  • the high pressure valve member 234 is biased towards high pressure valve seat 236 by spring 237 and actuation of the solenoid reverses the sense of the overall biasing.
  • the integrated high and low pressure valves are held in place in a chassis 238 by an interference fit with oil seals 239 dividing connections to the low and high pressure manifolds 240, 242.
  • a tube of a non-magnetic material 244 e.g. plastics material, non-magnetic stainless steel, or brass
  • a further tube of non-magnetic material 248 is provided outside the cylinder to define the magnetic flux path and guide flux through the high pressure valve armature.
  • Figures 7A and 7B illustrate a detail of Figure 6.
  • the high pressure valve armature is located adjacent a protrusion 250 in a magnetic circuit member such that when the high pressure valve member moves axially, towards the solenoid, from the valve closed position, in which the high pressure valve member has the position illustrated in Figure 7A to the valve open position, in which the high pressure valve member has the position illustrated in Figure 7B, the reluctance of a magnetic circuit path 252 through the protrusion and the high pressure valve member is increased, to maximise the passage of flux through magnetic circuit path 254, reducing the total current and therefore power consumption required to hold the high pressure valve member open against a given pressure differential.
  • Layout 7A initially allows lots of flux to enter and exit the HPV armature in a radial direction with low reluctance so that good force can be generated on the LPV.
  • this pressure pulse helps HPV armature move upwards (alternatively the radial flux path can be made thin enough to start saturating after which some flux is forced to enter or leave axially generating an axial up force).
  • the flux path radially across the HPV armature gets cut off (due to the 'protrusion' 250 the radial flux path reduces in area as armature moves upwards) and flux is forced to flow axially and generates an axial upforce.
  • the flux flow enters and or exits the armature in an axial direction generating a strong latching force and current can then be dropped to give efficient latching.
  • Figure 8 shows the variation in low pressure valve position 300A, high pressure valve position 302A, the value of a shared control signal (e.g. the current through a solenoid) 304A and working chamber pressure 306A (which is illustrated relative to the low pressure manifold pressure 308) during a pumping cycle, as well as the variation in low pressure valve position 300B, high pressure valve position 302B the value of a shared control signal (e.g. the current through a solenoid) 304B and working chamber pressure 306B during a motoring cycle.
  • a shared control signal e.g. the current through a solenoid
  • the timing of events is shown relative to cycles of working chamber volume 310 between the point of maximum volume, bottom dead centre (BDC) and point of minimum volume, top dead centre (TDC) and is applicable to the valves illustrated in Figures 4A, 4B, 4C, 5 and 6.
  • a current (functioning as the shared control signal) is passed through the solenoid (functioning as the shared actuator).
  • a closing force is applied to the low pressure valve member and an opening force is applied to the high pressure valve member.
  • the force from the armature exceeds the biasing force from the respective spring, changing the sense of the net biasing on the respective valve members.
  • the low pressure valve begins to open straight away, leading to an active pumping cycle (if in the alternative no signal is sent, the low pressure valve remains open and an idle cycle takes place).
  • the high pressure valve closes passively when the piston reaches top dead centre and the working chamber begins to expand again.
  • the low pressure valve then opens once the pressure within the working chamber is sufficiently close to the low pressure manifold that the spring biasing the low pressure valve can overcome the force due to the pressure differential across the low pressure valve member.
  • a current is applied to the solenoid shortly before top dead centre. This causes the low pressure valve to immediately close, however, the high pressure valve cannot immediately open due to the pressure differential between the working chamber and the high pressure manifold. However, once the working chamber is sealed, the pressure rises rapidly until the high pressure valve opens. Once the high pressure valve has opened, the average solenoid current which is required to maintain the low pressure valve in the closed position and high pressure valve in the open position is reduced, and so the average current through the solenoid is reduced, by using pulse wave modulation, and reducing the mark to space ratio of the current pulses as far as possible. This reduces overall energy consumption. Thus, there is a step change decrease 312 in the mean current through the solenoid, once the low pressure valve is closed and the high pressure valve has opened.
  • the invention has provided a mechanism which is compact and which can be made cost effectively, as it requires only a single actuator, such as a single solenoid. Only a single shared control signal is required to enable both the low and high pressure valves to be actively controlled, to enable the hydraulic machine to select between active and inactive cycles. This reduces wiring requirements and simplifies control.
  • the timing of the single shared control signal relative to cycles of working chamber volume enables the controller to select between active pumping and motoring cycles.
  • the timing of the single shared control signal relative to cycles of working chamber volume (the phasing) can be varied to determine the precise fraction of maximum working chamber volume which his displaced during each active cycle.
  • the force which is required to hold them (in the closed position in the case of the low pressure valve and the open position in the case of the high pressure valve member) is reduced and, particularly during motoring cycles, power consumption can be reduced, for example, by reducing the average current through the solenoid, thereby increasing overall efficiency of the machine.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Magnetically Actuated Valves (AREA)
  • Reciprocating Pumps (AREA)
  • Details Of Reciprocating Pumps (AREA)
PCT/JP2012/000864 2012-02-09 2012-02-09 Fluid working machine with valve actuation WO2013118180A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP12706116.6A EP2839155B1 (en) 2012-02-09 2012-02-09 Fluid working machine with valve actuation
PCT/JP2012/000864 WO2013118180A1 (en) 2012-02-09 2012-02-09 Fluid working machine with valve actuation
JP2013504996A JP5536276B1 (ja) 2012-02-09 2012-02-09 流体作動機械の弁作動

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2012/000864 WO2013118180A1 (en) 2012-02-09 2012-02-09 Fluid working machine with valve actuation

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WO2013118180A1 true WO2013118180A1 (en) 2013-08-15

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JP (1) JP5536276B1 (ja)
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Cited By (3)

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GB2529909A (en) * 2014-09-30 2016-03-09 Artemis Intelligent Power Ltd Industrial system with synthetically commutated variable displacement fluid working machine
US9732748B2 (en) 2013-03-01 2017-08-15 Artemis Intelligent Power Limited Valve unit and a fluid working machine comprising a valve unit
EP3486482A1 (en) * 2017-11-17 2019-05-22 Artemis Intelligent Power Limited Measuring hydraulic fluid pressure in a fluid-working machine

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2018115580A (ja) * 2017-01-17 2018-07-26 いすゞ自動車株式会社 ランキンサイクル
JP2020165349A (ja) * 2019-03-28 2020-10-08 いすゞ自動車株式会社 流体作動機械

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EP0361927A1 (en) 1988-09-29 1990-04-04 Artemis Intelligent Power Ltd. Pump control method and poppet valve therefor
EP0494236A1 (en) 1988-09-29 1992-07-15 Univ Edinburgh FLUID MACHINE.
EP1429020A1 (en) * 2002-12-09 2004-06-16 Caterpillar Inc. Variable discharge pump
EP2064474A1 (en) 2006-09-08 2009-06-03 Artemis Intelligent Power Limited Fluid-working machine
WO2009153605A1 (en) * 2008-06-20 2009-12-23 Artemis Intelligent Power Limited Fluid working machines and methods
EP2239463A1 (en) * 2009-04-07 2010-10-13 Artemis Intelligent Power Limited Fluid working machine and method of operating a fluid working machine
EP2322802A1 (en) * 2009-11-13 2011-05-18 Artemis Intelligent Power Limited Electronically controlled valve
EP2329172A2 (en) 2008-09-09 2011-06-08 Artemis Intelligent Power Limited Valve assemblies

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EP0361927A1 (en) 1988-09-29 1990-04-04 Artemis Intelligent Power Ltd. Pump control method and poppet valve therefor
EP0494236A1 (en) 1988-09-29 1992-07-15 Univ Edinburgh FLUID MACHINE.
EP1429020A1 (en) * 2002-12-09 2004-06-16 Caterpillar Inc. Variable discharge pump
EP2064474A1 (en) 2006-09-08 2009-06-03 Artemis Intelligent Power Limited Fluid-working machine
WO2009153605A1 (en) * 2008-06-20 2009-12-23 Artemis Intelligent Power Limited Fluid working machines and methods
EP2329172A2 (en) 2008-09-09 2011-06-08 Artemis Intelligent Power Limited Valve assemblies
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Publication number Priority date Publication date Assignee Title
US9732748B2 (en) 2013-03-01 2017-08-15 Artemis Intelligent Power Limited Valve unit and a fluid working machine comprising a valve unit
GB2529909A (en) * 2014-09-30 2016-03-09 Artemis Intelligent Power Ltd Industrial system with synthetically commutated variable displacement fluid working machine
GB2529909B (en) * 2014-09-30 2016-11-23 Artemis Intelligent Power Ltd Industrial system with synthetically commutated variable displacement fluid working machine
US10180135B2 (en) 2014-09-30 2019-01-15 Artemis Intelligent Power Limited Industrial system with synthetically commutated variable displacement fluid working machine
EP3486482A1 (en) * 2017-11-17 2019-05-22 Artemis Intelligent Power Limited Measuring hydraulic fluid pressure in a fluid-working machine
US11073147B2 (en) 2017-11-17 2021-07-27 Artemis Intelligent Power Limited Measuring hydraulic fluid pressure in a fluid-working machine

Also Published As

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JP2014522459A (ja) 2014-09-04
EP2839155A1 (en) 2015-02-25
EP2839155B1 (en) 2016-08-24
JP5536276B1 (ja) 2014-07-02

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