Abstract: The described system and method allow a controller to calibrate a transmission variator of a continuously variable transmission for torque control by obtaining static and dynamic qualities and parameters of the variator through an automated calibration procedure. The system and method employ a pair of transmission mode configurations and operational configurations in combination to obtain system-specific information. In this way, the system is able to calibrate out the system variations to provide effective feed forward torque control of the continuously variable transmission. In an embodiment, a first calibration operation is performed while the transmission is neutralized and a second calibration operation is performed while the transmission is engaged in a mode providing a fixed variator output speed.

Abstract: A method of braking a hydrostatic drive machine includes steps of reducing a displacement of a pump of a hydrostatic drive system to a non-zero displacement, and increasing a displacement of a motor of the hydrostatic drive system to a displacement that is less than a maximum displacement. The method also includes a step of accelerating an engine of the hydrostatic drive system toward a desired engine speed range.

Abstract: An electric power actuator and a method of controlling such an actuator are disclosed. The actuator (1) can include means (17, 26) for limiting the pressure difference in both chambers (9, 10) of a hydraulic jack (8) of the actuator (1) to a limit pressure which is lower than an opening pressure of a pressure relief valve (11) of the actuator (1).

Abstract: A control system for a machine is disclosed. The control system may have a pump, a low pressure reservoir, and at least one actuator connected to receive fluid pressurized by the pump and discharge fluid to the low pressure reservoir. The control system may also have a bypass passage situated to allow fluid to bypass the at least one actuator, and a warmup valve disposed within the bypass passage and being movable between a flow-passing position and a flow-blocking position. The control system may further have a hydraulic temperature sensor configured to generate a signal indicative of a temperature of the fluid, and a controller in communication with the pump, the warmup valve, and the hydraulic temperature sensor. The controller may be configured to move the warmup valve to the flow-passing position, fix a displacement position of the pump, and adjust an input speed of the pump in response to the signal.

Abstract: A hydraulic system incorporating a modified spool controlling hydraulic fluid flow to non-load sensing functions for use with a load-sensing pump is described. The hydraulic system comprises a hydraulically piloted stroke valve for providing a load sensing signal to the load-sensing pump when the non-load sensing functions are operated.

Abstract: A hydraulic fan circuit is disclosed. The hydraulic fan circuit may have a primary pump, a motor, a fan connected to and driven by the motor, and a flywheel connected to and driven by one of the motor and the fan. The hydraulic fan circuit may also have a supply passage extending from the primary pump to the motor, a return passage extending from the motor to the primary pump, and a diverter valve configured to selectively connect the supply passage to a low-pressure sump.

Abstract: The present invention relates to a hydraulic drive system for driving an apparatus, with a drive unit, a first and a second hydraulic displacement machine, with which the drive unit is connectable or connected for transmitting mechanical energy, and a third and a fourth hydraulic displacement machine, which are connectable or connected with the apparatus for transmitting mechanical energy, wherein the first hydraulic displacement machine is hydraulically connected or connectable with the third hydraulic displacement machine, and wherein a high-pressure accumulator is provided, which is hydraulically connected or connectable with the second and the fourth hydraulic displacement machine.

Abstract: A working fluid cooling control system has a controller 100 that receives inputs signals from a traveling motor speed pickup 101, a pressure sensor 102, a signal receiving line 103a of an option selecting switch 103 and a temperature sensor 104. The controller performs predetermined arithmetic processing and controls proportional solenoid valves 105 and 106. The pressures controlled by the solenoid valves are compared with positive control command pressures in shuttle valves 109 and 110. In this way, in the case of an operation pattern corresponding to a rise in temperature of the working fluid, minimum tilting angles of hydraulic pumps 11 and 12 are increased to increase an average flow rate of the working fluid passing through an oil cooler 40, thereby increasing an average heat discharge amount and reducing an equilibrium temperature of the working fluid.

Abstract: A simplified method for calibrating a variable-displacement hydraulic PTO system on an agricultural windrower when powering a header wherein the variable-displacement pump is operated at maximum flow capacity while the engine is operated at a pre-determined speed and a flow balance valve is adjusted to achieved a pre-determined cutterbar speed. Operation of the cutterbar at the pre-determined speed allows sufficient hydraulic fluid flow through the remaining parallel fluid circuit to power the remaining equipment, typically a reel, on the header. Controls for managing pump displacement and engine speed as well as indication of cutterbar speed are typically available on the windrower tractor thereby eliminating the need for additional diagnostic equipment and making the method suitable for use in the field.

Abstract: The present invention is a device for converting rotational energy into useable power by buffering the created rotational energy from the rotational energy used to create the output power. Thus, in one embodiment, a pendulum within a buoy is used to create rotational energy from ocean wave movement and the created rotational energy then drives a hydraulic pump which in turn drives a hydraulic motor to create a second rotational force which is then used to create an electrical output. In this manner, the hydraulic fluid acts as the buffer between the wave-created rotational energy and the rotational energy actually used to create the output electricity.

Abstract: The present invention relates to a servo-control (1) provided with at least one body (2) defining an inside space (10) together with a slider element (11) having a control piston (12) suitable for sliding in said inside space (10), said control piston (12) subdividing said inside space (10) into a retraction chamber (4) and an extension chamber (3). The servo-control (1) has at least one limit force detector device (20) comprising a casing (21) secured to said body (2) and defining a detection space (22). Furthermore, a movable member (50) subdivides said detection space (22) into a first detection chamber (26) opening out to said inside space (10) and a second detection chamber (27). Finally, the device includes detector means (29) for detecting the position of said movable member (50) in said detection space (22).

Abstract: An auxiliary hydraulic power generation system includes a first spool including a turbine. A fan is coupled to the first spool, the fan operable to drive the first spool in a windmill condition in which the turbine fails to provide rotational drive to the fan. An auxiliary variable displacement hydraulic pump is selectively driven by the first spool in the windmill condition to augment a hydraulic power source.

Abstract: A speed of a hydraulic actuator is matched with that of an electric actuator when the hydraulic actuator and the electric actuator are concurrently actuated. When determination units (71, 72) determine that a boom hydraulic cylinder (31) and a rotation generator motor (11) are concurrently actuated based on a controlled variable of a boom control lever (41) and a controlled variable of a rotation control lever (42), a torque of the rotation generator motor (11) is restricted based on a pump discharge pressure (Pp). Therefore, for example, a torque limit command is generated and output such that a torque limit value (TL2) of the rotation generator motor (11) is decreased with a decrease in discharge pressure (Pp) of a hydraulic pump (3).

Abstract: The invention relates to a hydraulic drive device, comprising a piston which is guided displaceably in a cylinder chamber along a working axis and adjoins a working pressure chamber that can be pressurized by hydraulic fluid, and comprising a control means that is guided in the piston at least in some sections between different control states in order to control the flow of the hydraulic fluid from a high pressure supply into the working pressure chamber to move the piston in the working direction and from the working pressure chamber to a return flow chamber, wherein the region of the piston facing away from the working pressure chamber delimits a low pressure chamber that is pressurized by a low pressure supply for hydraulic fluid during the operation of the device such that the piston is moved back against the working direction when the control means connects the working pressure chamber to the return flow chamber. The invention furthermore relates to a method for operating a hydraulic drive device.

Abstract: The present disclosure provides embodiments directed towards a method and a system for fine control of hydraulic cranes. In one embodiment, a system is provided. The system includes a service pack having an engine. The engine has an operating speed ranging from a low speed to a high speed, a hydraulic pump coupled to the engine, wherein the hydraulic pump is configured to supply a hydraulic output to a hydraulic load, and a control system configured to control the hydraulic output. The control system includes a fine control mode configured to lock the engine in the low speed and control the hydraulic output in proportion to a percentage of a trigger activation.

Abstract: A control system for a swashplate pump is disclosed. The control system may have a tiltable swashplate, at least one actuator movable to tilt the swashplate, a supply of pressurized fluid, and a drain. The control system may also have a first circuit connectable to the supply of pressurized fluid and to the drain and configured to control operation of the at least one actuator, and a second circuit connectable to the supply of pressurized fluid and to the drain and configured to control operation of the at least one actuator. The control system may further have a failsafe valve configured to connect the first circuit to at least one of the supply and the drain only during a normal operating condition, and to connect the second circuit to the supply and to the drain only during a failsafe condition.

Abstract: A drivetrain system for use in a mobile machine is disclosed. The drivetrain system may have a first rotary fluid actuator, a second rotary fluid actuator, an input device, and a controller in communication with the first rotary fluid actuator, the second rotary fluid actuator, and the input device. The controller may be configured to determine a desired change in an effective gear ratio of the drivetrain system, and determine a total displacement change associated with the first and second rotary fluid actuators that produces the desired change in the effective gear ratio. The controller may also be configured to compare the total displacement change to a threshold change level, affect simultaneous displacement changes in the first and second rotary fluid actuators when the total displacement change exceeds the threshold change level, and affect sequential displacement changes in the first and second rotary fluid actuators when the total displacement change is less than the threshold change level.

Abstract: A hydrostatic stepless transmission comprises: a hydraulic pump; a hydraulic motor, wherein at least one of the hydraulic pump and motor is variable in displacement, and is provided with a movable swash plate; a closed circuit connecting the hydraulic pump and motor to each other through a pair of main fluid passages, wherein one main fluid passage is higher-pressurized during forward traveling, and wherein the other main fluid passage is higher-pressurized during backward traveling; a hydraulic servomechanism for controlling a tilt angle of the movable swash plate of the at least one of the hydraulic pump and motor; a speed-controlling motive member attached to the hydraulic servomechanism, wherein the speed-controlling motive member interlocks with the movable swash plate and is moved by operating a speed control operation lever; and a load controlling system attached to the hydraulic servomechanism.

Abstract: An electro-hydraulic control system for pump control is disclosed. The hydraulic actuator is configured to control the inclination of a swashplate. The position of the hydraulic actuator is controlled by controlling the flow of pressurized fluid into and out of two pressure chambers, one on either side of the actuator. A fluid passageway is provided that selectively connects the passageway to tank. The passageway has an orifice for each pressure chamber, and the actuator is configured to selectively block all or a portion of one or more of the orifices, depending on the position of the actuator. The components of the control system are configured such that the actuator will return to a neutral or near-neutral position upon loss of electric power.

Abstract: A transmission for use with a machine is disclosed. The transmission may have a pump, a motor fluidly connected to receive pressurized fluid from the pump and propel the machine, and an operator input device configured to generate a signal indicative of an operator desired gear ratio of the transmission. The transmission may also have a controller in communication with the pump, the motor, and the operator input device. The controller may be configured to determine an desired gear ratio of the transmission as a function of the signal, and determine an efficiency loss of the transmission at the desired gear ratio. The controller may also be configured to select a known setting of at least one of the pump and motor that provides the desired gear ratio and accounts for the efficiency loss.

Abstract: A control system for a variable displacement hydraulic pump is disclosed. The control system utilizes two flow control valves to provide a flow of hydraulic fluid to two control actuators. The control actuators create opposing moments on the pump swashplate to control swashplate orientation and pump displacement.

Abstract: An open center hydraulic system that includes a variable displacement pump having an inlet, an outlet and a sensing port, the pump configured to provide reduced fluid flow in response to a predetermined fluid pressure differential between the outlet and the sensing port. A first fluid circuit and a second fluid circuit each serve as signal lines with the pump sensing port. During operation of the second fluid circuit, reduced fluid flow from the pump outlet is achieved as a result of the sum of induced fluid pressure reductions of respective controlled pressure reduction devices approaching the predetermined pump fluid pressure differential.

Abstract: A hydraulic servo drive device includes: a pilot spool for switching supply and shutoff of oil; a servo piston slid in accordance with the pilot spool; a stroke sensor for detecting a displacement of the servo piston; a first hydraulic chamber in which oil for moving the servo piston is flowed; a first piston oil path for communicating a pump port to which oil is supplied from a pump with a first hydraulic chamber; and a discharge circulating oil path for communicating the first hydraulic chamber with a drain port.

Abstract: A hydraulic system including a hydraulic power source (102) having an output and a directional control valve (106) coupled to the output of the hydraulic power source. The system also includes a hydraulic cylinder (108) coupled to the directional control valve that receives hydraulic fluid at a first port and expels it at a second port as it moves a load (114) at a movement rate, a fixed displacement motor (150) coupled the directional control valve and receiving hydraulic fluid expelled by the hydraulic cylinder and a variable displacement pump (154) attached to a drive arm (152) of the motor.

Abstract: A system is provided for dynamically affecting a force applied through at least one axle of a rail vehicle configured to travel along a rail track. The rail vehicle includes a plurality of axles and a plurality of wheels received by the plurality of axles. The system includes a device configured to selectively impart the force through the at least one axle to control a respective weight of the at least one axle on the rail track for affecting a traction performance of the rail vehicle traveling along the rail track.

Abstract: A control device includes an arm cylinder having a cylinder body and a piston that slides inside the cylinder body and a pump that supplies working oil to the arm cylinder, and decelerates the piston when it approaches a stroke end of the arm cylinder by adjusting a supply rate of the working oil supplied from the pump to the arm cylinder and a discharge rate of the working oil discharged from the arm cylinder. The position at which the piston starts decelerating is set further from the stroke end as the moving speed of the piston becomes higher.

Abstract: A hydrostatic pump (1) with a variable delivery volume can be operated in a closed circuit. An electrically controllable actuator device (4) is provided for the control of the delivery volume of the pump (1). The electrically controllable actuator (4) has an electrically actuatable control valve device (6) which generates a positioning pressure which actuates a positioning piston device (5) which is in an operative connection with a delivery volume control device (3) of the pump. An electrical position feedback circuit (21) of the delivery volume control device (3) is provided and the actuator device (4) is provided with a switchable hydraulic neutral position control system (25), by means of which a restoring movement can be generated that acts on the positioning piston device (5) and places the delivery volume control device (3) into a neutral position.

Abstract: The invention is a hydraulic fluid pump of a vehicle brake system, which has a delivery device for delivering hydraulic fluid against a hydraulic counter-pressure prevailing in a section of the vehicle brake system. The hydraulic fluid pump further has a mechanism for modifying the volume delivered by the delivery device in accordance with the level of the hydraulic counter-pressure.

Abstract: A traveling control device for a hydraulically-driven vehicle includes: a traveling hydraulic motor driven by oil delivered from a hydraulic pump; a speed-reducing mechanism with an adjustable speed-reduction ratio, that slows down rotation of the hydraulic motor and transmits the slowed rotation to wheels; a pressure oil control device that controls a flow of pressure oil from the hydraulic pump to the hydraulic motor in correspondence to an extent to which a traveling pedal is operated; a speed-reduction ratio detection device that detects the speed-reduction ratio at the speed-reducing mechanism; and an acceleration limiting device that restricts accelerating operation of the hydraulic motor achieved in response to an operation of the traveling pedal, when an acceleration-limiting condition, that is, the speed-reduction ratio detected by the speed-reduction ratio detection device is equal to or greater than a predetermined value, is met.

Abstract: The present disclosure provides a machine configured so that its ground speed is at least in part dependent on the measured force that is applied to an attachment attached thereto. The present disclosure also provides an attachment for a machine that is configured to provide feedback to the machine it is configured to be attached to, wherein the feedback is representative of the force applied to the attachment. The present disclosure also provides a method of automatically controlling the ground speed of a machine based on feedback measured in an attachment attached to the machine.

Abstract: Disclosed is a work machine having a traveling apparatus and a work implement driven by an engine. A hydraulic system mounted on the work machine includes an HST pump comprising a swash plate, variable displacement pump driven by the engine, an HST motor connected in a closed circuit to the HST pump and a pair of speed-changing oil passageways, the HST motor being driven by an amount of oil supplied by the HST pump, thereby to drive the traveling apparatus, a main pump driven by the engine, the main pump supplying pressure oil to the work implement, a pilot pump driven by the engine, a swash plate positioning circuit configured to effect positioning of a swash plate of the HST pump with pilot oil supplied from the pilot pump, and a bleed circuit configured to drain, via a throttle, a portion of the pilot oil supplied to the swash plate positioning circuit.

Abstract: Generally, the invention relates to power generation and energy storage. In particular, to systems and methods for providing constant power from hydraulic inputs having widely-varying pressures. More particularly, the invention relates to hydraulic-pneumatic energy storage and recovery systems that include either a fixed or variable displacement hydraulic motor and control systems that allow a user to maintain constant power from the fixed or variable displacement hydraulic motor.

Abstract: A system and method for controlling a variator operate to detect variator torques and/or internal pressures and generates a preliminary corrective command. The preliminary corrective command is transformed via a dynamic transform to account for system characteristics during transient operating conditions such as machine acceleration, such that the acceleration of the system during transient periods is not torque-limited by static torque-control map values. In an embodiment, the acceleration may be positive or negative, and in a further embodiment, braking is automatically applied in the case of negative requested power or desired machine retarding.

Abstract: A method of controlling a motor includes monitoring a pressure in a circuit supplying a pressurized fluid to the motor, determining a difference between the monitored circuit pressure and a desired circuit pressure, and determining an actuator command for an actuator that is capable of adjusting a pressure of the pressurized fluid supplied to the motor. The actuator command is determined based on the difference between the monitored circuit pressure and the desired circuit pressure, and is independent of a position of the actuator. The method also includes operating the actuator based on the actuator command.

Abstract: It is an object to accurately control swash plate angles of movable swash plates of a hydraulic pump and/or a hydraulic motor. In a hydraulic stepless speed changing device, a hydraulic pump and/or a hydraulic motor, at least one of which is of a variable displacement type, and a hydraulic servo mechanism for controlling swash plate angles of movable swash plates of the hydraulic pump and/or the hydraulic motor are integrated and the movable swash plates are tilted thorough operation of a speed change operation lever. Load control mechanisms are formed by integrally providing actuators having a cylinder, a spool, and the like for sliding speed change drive members to the speed reduction side, the speed change drive members tilting the movable swash plates of the hydraulic servo mechanism. The load control mechanisms are actuated by pressurized oil led from a main oil path of a closed circuit formed by connecting the hydraulic pump and the hydraulic motor to the actuators.

Abstract: A hydrostatic differential transmission comprising a cylinder housing containing an input pump and an output pump. The two hydraulic pumps are mounted with the output pump inside the input pump. The input pump has an adjustable swash plate. The output pump has a fixed swash plate. The pistons of the input and output pumps share inter-connected piston bore housings. An adjustable control selectively pivots the adjustable swash plate between a neutral position, where the swash plate is at a 90 degree angle to the input shaft and maximum tilt of the swash plate for a one-to-one ratio of the input shaft and output shaft.

Abstract: A variable displacement pump including a drive shaft, a cam ring eccentrically moveable with respect to an axis of the drive shaft, and a solenoid drivingly controlled on the basis of variation in electric current amount to be supplied to the solenoid which is controlled in accordance with an operating condition of a vehicle. The solenoid is configured such that a rate of change in the specific discharge amount relative to the electric current amount to be supplied to the solenoid under a condition that the specific discharge amount is smaller is reduced as compared to a rate of change in the specific discharge amount relative to the electric current amount to be supplied to the solenoid under a condition that the specific discharge amount is larger.

Abstract: A flow rate control device of a hydraulic pump in a power steering system, may include an upper cam ring having a cam profile, which is fixedly installed, a lower cam ring having a cam profile, which is engaged with the upper cam ring to be relatively rotatable about the upper cam ring, and a rotor including a plurality of veins and engaged with the upper and lower cam rings to form an inner space therebetween to pressurize oil by protruding the veins in the inner space by centrifugal force while rotating.

Abstract: A hydraulic driver for powering the conditioner mechanism on an agricultural mower-conditioner, the hydraulic driver being powered by the same hydraulic power circuit that powers the cutting mechanism, but which includes controls for varying the speed and/or direction of rotation of the conditioner mechanism independent from the speed of the cutting mechanism.

Abstract: A method of detecting a fluid leak in a hydraulic fluid circuit includes preventing fluid from entering the circuit when an actual outlet flow rate from a pump is positive while a requested outlet flow rate to a hydraulic machine is zero. An outlet port of a variable displacement port can be selectively blocked, while in a fixed displacement pump (FDP) fluid can be diverted from the outlet port to a secondary fluid circuit. The actual outlet flow rate can be measured using a flow sensor or a swash plate angle depending on the pump design. A hydraulic fluid circuit includes a hydraulic machine, a pump, a valve at an outlet port of the pump, and a controller. The controller determines the requested flow rate, and actuates the valve to prevent fluid from entering the circuit whenever the actual outlet flow rate is positive during zero requested flow rate.

Abstract: An apparatus and method for varying the speed of a reel versus ground speed of an agricultural windrower, wherein a programmable control module in connection with a signal operated device operable for controlling operation of the reel, is programmed to operate in an automatic mode to control the reel speed as a percentage of the ground speed, while preventing the reel speed from falling below a minimum value.

Abstract: Electronic control for a hydraulic system to drive an auxiliary power source is provided, with an application as a system for controlling the operation of a hydraulically driven AC generator. The system includes a hydraulic pump, a hydraulic motor drivably connected to the generator, and a fluid circuit for circulating fluid from the pump to the motor and back. The feedback circuit contains a feedback conduit to feedback the motor. The system also includes a proportional servo control valve assembly for controlling the fluid conduits and a control circuit for controlling the control valve assembly to thereby control the flow of fluid to the motor. Sensors for measuring the operating parameters of the system and an operator interface module are both able to influence the operation of the system.

Abstract: A hydraulic system includes a variable displacement hydraulic pump connectable to a power source, a hydraulic motor, a fluid circuit, a pump displacement control, and a controller. The pump has an inlet for receiving fluid, an outlet for discharging pressurized fluid, and a pump displacement input. The motor has an inlet for receiving pressurized fluid and an outlet for discharging spent fluid. The fluid circuit includes a supply conduit for conducting fluid discharged by the pump to the motor and a return conduit for returning fluid discharged by the motor to the pump. The pump displacement control cooperates with the pump displacement input to vary pump displacement. The controller communicates with the pump displacement control to control the pump output such that the motor is driven at a constant speed to thereby drive a generator connected to the motor at a constant speed despite speed fluctuations of the power source.

Abstract: A hydraulic drive device capable of utilizing return oil effectively while maintaining a driven speed of a hydraulic actuator, as well as a working machine having the hydraulic drive device, are provided. The hydraulic drive device includes a controller. During an external force applying period in which a return oil pressure exceeds a discharge pressure from a hydraulic pump, the controller specifies a regenerating flow rate capable of being conducted to a regeneration oil passage and a surplus flow rate other than the regenerating flow rate on the basis of power required of the hydraulic pump out of return oil other than return oil which is conduced to a tank through a control valve, then conducts the return oil of the regenerating flow rate to the regeneration oil passage and controls an MO valve and a regulator so that the return oil of the surplus flow rate is conducted to an outlet oil passage.

Abstract: A method of braking a hydrostatic drive machine includes steps of reducing a displacement of a pump of a hydrostatic drive system to a non-zero displacement, and increasing a displacement of a motor of the hydrostatic drive system to a displacement that is less than a maximum displacement. The method also includes a step of accelerating an engine of the hydrostatic drive system toward a desired engine speed range.

Abstract: A fluid power system comprises a pump with multiple independently variable outlets (11, 12, 13, 14), each of which is capable of delivering fluid in individually controllable volume units and a plurality of hydraulic loads (15, 16, 18, 20). A system of switching valves is configured to create fluid connections between the pump outlets and the loads. A control system commands both the pump and the switching valves, so as to create valve state combinations to satisfy load conditions as demanded by an operator The number of pump outlets (11, 12, 13, 14) connected to one or more of the loads (15, 16, 18, 20) is changeable to satisfy the flow required of the load due to the operator demand, each pump outlet being commanded to produce a flow depending on the status of other outlets connected a load to which the outlet is connected and the operator demand for that load.

Abstract: The invention relates to a method for braking a vehicle, driven by means of a hydrostatic gearbox (28) and a hydrostatic drive. The hydrostatic gearbox (28) comprises at least one adjustable hydrostatic motor (6,6). The vehicle driven by means of the hydrostatic gearbox (28) may be retarded by an operating brake. On recognition of a certain braking process, the hydraulic motor (6,6) is adjusted to a minimal pivot angle. On recognition of a termination of the certain braking process, the hydraulic motor (6,6) is adjusted to a pivot angle which matches the speed achieved after the braking process.

Abstract: A drivetrain system for use in a mobile machine is disclosed. The drivetrain system may have a first rotary fluid actuator, a second rotary fluid actuator, an input device, and a controller in communication with the first rotary fluid actuator, the second rotary fluid actuator, and the input device. The controller may be configured to determine a desired change in an effective gear ratio of the drivetrain system, and determine a total displacement change associated with the first and second rotary fluid actuators that produces the desired change in the effective gear ratio. The controller may also be configured to compare the total displacement change to a threshold change level, affect simultaneous displacement changes in the first and second rotary fluid actuators when the total displacement change exceeds the threshold change level, and affect sequential displacement changes in the first and second rotary fluid actuators when the total displacement change is less than the threshold change level.

Abstract: A control circuit for a coiled tubing injector includes a circuit controller (14). One or more counterbalance valves (3) may be responsive to the circuit controller to prevent the tubing string from descending into the wellbore during rate of penetration movement. In one embodiment, a control valve (4) allows fluid to flow through a bypass line around the counterbalance valves when drilling in a weight-on-bit mode. Other hydraulic control circuits allow for the release of fluid pressure to control the injector hydraulic motor. In yet another embodiment, the control circuit regulates power to an electric motor of the injector.

Abstract: A transmission for use with a machine is disclosed. The transmission may have a pump, a motor fluidly connected to receive pressurized fluid from the pump and propel the machine, and an operator input device configured to generate a signal indicative of an operator desired gear ratio of the transmission. The transmission may also have a controller in communication with the pump, the motor, and the operator input device. The controller may be configured to determine an desired gear ratio of the transmission as a function of the signal, and determine an efficiency loss of the transmission at the desired gear ratio. The controller may also be configured to select a known setting of at least one of the pump and motor that provides the desired gear ratio and accounts for the efficiency loss.