Power machines, control systems and methods that adjust engine speed based upon actuation of user input controls that control other power machine functions such as travel functions and lift arm functions. By controlling engine speed at least partially in response to the user input devices controlling other machine functions, more optimal engine speeds can be achieved.

Operating a machine including a continuously variable transmission (CVT) includes operating an engine of the machine at a lower engine speed, receiving data indicative of an expected increase in load on the engine, and commanding increasing the engine speed responsive to the data. The engine is operated at a higher engine speed responsive to the commanded increase, with the operation at the higher engine speed being initiated proactively so as to limit retarding a ground speed of the machine. Related control logic and machine structure is also disclosed.

A prime mover and a plurality of hydraulic actuators, a hydraulic machine having a rotatable shaft in driven engagement with the prime mover and comprising a plurality of working chambers, a hydraulic circuit extending between a group of one or more working chambers of the hydraulic machine and one or more of the hydraulic actuators, each working chamber of the hydraulic machine comprising a low-pressure valve which regulates the flow of hydraulic fluid between the working chamber and a low-pressure manifold and a high-pressure valve which regulates the flow of hydraulic fluid between the working chamber and a high-pressure manifold. The hydraulic machine being configured to actively control at least the low-pressure valves of the group of one or more working chambers to select the net displacement of hydraulic fluid by each working chamber on each cycle of working chamber volume, and thereby the net displacement of hydraulic fluid by the group of one or more working chambers, responsive to a demand signal, wherein the apparatus further comprises a controller configured to calculate the demand signal in response to a measured property of the hydraulic circuit or one or more actuators.

A maintenance device for a construction machine includes: an abnormality detection means for detecting abnormality of an apparatus installed on the construction machine; an abnormality information output means for outputting abnormality information about the apparatus detected by the abnormality detection means; and a maintenance mode setting means for setting a maintenance mode for performing a maintenance work of the apparatus, wherein the abnormality information output means for eliminating negation or output of the information, if any abnormality of the apparatus is detected in a state in which the maintenance mode is set by the maintenance mode setting means.

A power transmission includes first and second clutches for switching a transmission path for a driving force. A work vehicle includes a clutch controlling unit and an engine controlling unit. The clutch controlling unit is configured to determine which of first and second modes the transmission path is switched into based on which of a range of greater than or equal to a mode switching threshold and a range of less than or equal to the mode switching threshold a speed ratio parameter falls into, and is configured to output a clutch command signal causing one of the first and second clutches to be engaged corresponding to the determined mode. The engine controlling unit is configured to apply an offset to a rotational speed of an input shaft such that after switching into the determined mode, the speed ratio parameter deviates from the mode switching threshold in the switched mode.

A hydraulic system is disclosed for assisting starting of a machine having an engine. The hydraulic system may include a work tool, a pump driven by the engine to pressurize fluid, and an actuator configured to receive pressurized fluid from the pump and move the work tool. The hydraulic system may also include an accumulator configured to selectively receive pressurized fluid from the pump and from the actuator, an electric starter configured to start the engine, and a motor selectively supplied with fluid from the accumulator to assist the electric starter in starting the engine.

A hydrostatic drive includes a diesel engine and a hydrostatic adjustable machine which supplies multiple consumers in normal operation as a pump. The machine has a pressure/flow regulator to which is communicated, according to the load-sensing principle, the highest load pressure of the consumers, in particular when the machine is operated as a pump. In order to realize a start/stop function of the diesel engine, a previously charged high-pressure reservoir supplies the hydrostatic machine, which then acts as a starter motor for the diesel engine. In order to switch from pump to starter motor, the hydro-machine is adjusted over zero. In order for this switch to take place quickly and reliably, the pressure/flow regulator is deactivated by means of a switching valve and the adjustment device is supplied with an adjustment pressure medium via the switching valve, which medium is taken from the high-pressure reservoir or from an auxiliary reservoir.

A hydraulic pump is driven by an engine. A hydraulic motor is driven by hydraulic fluid discharged from the hydraulic pump thereby causing a vehicle to travel. A controller controls a rotation speed of the engine and a displacement of the hydraulic pump. The controller acquires a tractive force of the vehicle. The controller changes the rotation speed of the engine to a low speed side in accordance with a reduction in the tractive force.

A prime mover and a plurality of hydraulic actuators, a hydraulic machine having a rotatable shaft in driven engagement with the prime mover and comprising a plurality of working chambers, a hydraulic circuit extending between a group of one or more working chambers of the hydraulic machine and one or more of the hydraulic actuators, each working chamber of the hydraulic machine comprising a low-pressure valve which regulates the flow of hydraulic fluid between the working chamber and a low-pressure manifold and a high-pressure valve which regulates the flow of hydraulic fluid between the working chamber and a high-pressure manifold. The hydraulic machine being configured to actively control at least the low-pressure valves of the group of one or more working chambers to select the net displacement of hydraulic fluid by each working chamber on each cycle of working chamber volume, and thereby the net displacement of hydraulic fluid by the group of one or more working chambers, responsive to a demand signal, wherein the apparatus further comprises a controller configured to calculate the demand signal in response to a measured property of the hydraulic circuit or one or more actuators.

A work vehicle includes a vehicle body, a travel device, a driving source, and a cooling device. The travel device is provided below the vehicle body. The driving source is disposed in a front part of the vehicle body. The driving source generates driving power for the travel device. The cooling device is disposed on one side in the vehicle width direction of the vehicle body and rearward of the driving source.