Abstract:
Die Erfindung betrifft ein Verfahren und eine Vorrichtung zur Regelung eines Drehmoments einer Triebwelle (4) einer hydrostatischen Maschine (5). Die hydrostatische Maschine (5) weist eine Stellvorrichtung zur Einstellung des Hubvolumens der hydrostatischen Maschine (5) auf. Das Verfahren weist folgende Schritte auf : Ein Soll -Drehmoment wird vorgegeben und ein eingestelltes Hubvolumen der hydrostatischen Maschine (5) erfasst. Ein Volumenstrom in die oder aus der Stellvorrichtung wird mittels eines Regelventils (19) zum Einstellen des Hubvolumens auf der Basis einer Kraftdifferenz zwischen einer Steuerkraft und einer in entgegengesetzter Richtung an dem Regelventil (19) angreifenden Kraft geregelt. Die Steuerkraft wird in Abhängigkeit des erfassten Hubvolumens und des erfassten Soll -Drehmoments bestimmt. Die in entgegengesetzter Richtung an dem Regelventil (19) angreifende Kraft ist eine hydraulische Kraft, die durch den an der Hochdruckseite der hydrostatischen Maschine (5) anliegenden Druck erzeugt wird.
Abstract:
A power pump performance analysis system and methods includes a signal processor connected to certain sensors for sensing pressures and stresses in the cylinder chambers and the inlet and discharge piping of a single or multicylinder pump. Pump speed and pump piston position may be determined by a crankshaft position sensor. Performance analyses for pump work performed, pump cylinder chamber stress, pump fluid end useful cycles to failure, and crosshead loading and shock analysis are provided for estimating pump component life and determining times for component replacement before failure.
Abstract:
The invention provides control apparatus for use with a fluid displacement device, for example a compressor, the control apparatus comprising means (24) to detect the temperature of fluid being displaced by the device and means (11) to control the device independence upon the sensor temperature. Preferably there is also means (22) to sense the pressure of the fluid being displaced by the device, a combination of temperature signals and pressure signals being utilised to control the device. The invention enables very sophisticated monitoring and control to be carried out, for example utilising pre-selected temperature and pressure bands.
Abstract:
A capacity control device in a variable capacity hydraulic pump comprising: a capacity control piston (6) provided with a large diameter chamber (7), for operating a capacity control member (5) of the variable capacity hydraulic pump (1) in a direction of decreasing or increasing the capacity by supplying or discharching pressure oil to or from said large diameter chamber (7); a first control valve (8) and a second control valve (9) for selectively allowing said large diameter chamber of said capacity control piston to communicate with a pump discharge path or a tank; said first control being set to a supply position by the pump discharge pressure and to a drain position by a spring linked with said capacity control piston through a feedback lever, and said second control valve being set to a first position for establishing communication between the pump discharge path and said large diameter chamber by the pump discharge pressure and to a second position for establishing communication between said large diameter chamber and said first control valve by negative pressure; wherein a flow sectional area of an oil path between said large diameter chamber and the pump discharge path or the tank is changed. With this arrangement, a change in the flow sectional area in an intermediate portion of the oil path can change the supply or discharge speed of the pump discharge pressure to the large diameter chamber of said capacity control piston, whereby the responsiveness of the capacity control of said variable hydraulic pump can be regulated, thereby improving the operability of a working machine.
Abstract:
The present disclosure relates to a method, a device, and a system for controlling a hydraulic pump of a construction machine, the system comprising: an engine; an engine control unit configured to control the engine by using engine limit torque information and current engine torque information of the engine; a hydraulic pump operated by power supplied from the engine; at least one actuator driven by a hydraulic pressure discharged from the hydraulic pump; and a hydraulic pump control device configured to control a limited swash plate angle of the hydraulic pump by using a torque of the hydraulic pump and the engine limit torque information received from the engine control unit.
Abstract:
A method for an automatic torque compensation of a compressor is provided. The method includes: obtaining a target speed and a feedback speed; generating a fluctuation speed according to the target speed and the feedback speed; generating a torque compensation angle according to the target speed and the fluctuation speed in a phase locked loop (PLL) manner; obtaining a load torque reference value and generating a torque compensation amplitude according to the load torque reference value; and generating a feedforward torque compensation value according to the target speed, the torque compensation angle and the torque compensation amplitude. A method for controlling a compressor, an apparatus for an automatic torque compensation of a compressor and a compressor including the apparatus are also provided.
Abstract:
A unit for calculating a compressor torque in a refrigeration cycle having a variable displacement compressor, a condenser, a pressure reducing mechanism and an evaporator, wherein the compressor torque is calculated from a pressure difference between a refrigerant discharge pressure and a refrigerant suction pressure of the compressor or a physical value having a correlation with the pressure difference, and a control unit using the same. The compressor torque may be adequately estimated without using a flow sensor.
Abstract:
The invention provides control apparatus for use with a fluid displacement device, for example a compressor, the control apparatus comprising means (24) to detect the temperature of fluid being displaced by the device and means (11) to control the device independence upon the sensor temperature. Preferably there is also means (22) to sense the pressure of the fluid being displaced by the device, a combination of temperature signals and pressure signals being utilised to control the device. The invention enables very sophisticated monitoring and control to be carried out, for example utilising pre-selected temperature and pressure bands.