A hybrid-type construction machine includes: a motor generator system connected to an internal combustion engine and performing a motor generator operation; an electric power accumulation system connected to the motor generator system; a load drive system connected to the electric power accumulation system and being driven electrically; an abnormality detection part equipped to the motor generator system, the electric power accumulation system and the load drive system; and a main control part determining whether an abnormality has occurred based on a detection value of the abnormality detection part. When the abnormality determination part determines that an abnormality has occurred, the main control part stops a drive of a drive system in which the abnormality is detected in the load drive system.

Provided is a hybrid-type construction machine including a swing device of the hydraulic-electric combined swing type and by which, in a work for which accurate swing operability is demanded like, for example, a crane work, a swing body is driven alone by the electric motor. The hybrid-type construction machine includes an engine, a hydraulic pump driven by the engine, a swing body, an electric motor for driving the swing body, and a hydraulic motor driven by the hydraulic pump for driving the swing body. The swing body is swung by simultaneous drive by the electric motor and the hydraulic motor. The hybrid-type construction machine includes a control apparatus having a work mode changeover unit by which an operator changes over a mode in response to an aspect of a work and an electric alone swing controlling unit configured to control the swing body to be swung by the electric motor alone. When a work in which position accuracy is demanded is selected by the work mode changeover unit, the swing body is swung by the electric alone swing controlling unit.

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.

There is provided a construction machine that achieves both safety and operability by lowering the possibility of an accident due to contact between the construction machine and a worker in the periphery of a vehicle body while securing operability in situations where an object required for work is present in the periphery. A controller has a normal mode as a control mode for making the operation limiting control effective and a temporary cancelation mode as a control mode for temporarily canceling the operation limiting control. The controller shifts to the temporary cancelation mode in response to operation of the control canceling device while in the normal mode. The controller shifts back to the normal mode in a case where a predetermined condition not responsive to operation of the control canceling device is satisfied while in the temporary cancelation mode.

An engine control system controls a work machine including an engine, a fuel injection device that injects fuel into the engine, and a hydraulic pump that is driven by the engine. The rotation state amount specification unit specifies a rotation state amount related to rotation of the engine. The injection amount determination unit determines a fuel injection amount by the fuel injection device based on the rotation state amount.

The gross output power of an engine distributed to at least one main machine and one auxiliary machine. A total load value calculation unit calculates the value of the lost power consumed by the auxiliary machine, and calculates the value of total load power by adding to this lost power value a target value for the main output power of the engine to be distributed to the main machine. A gross output value control unit controls the value of the gross output power so that the value of the gross output power becomes equal to the value of the total load power when the value of the total load power is less than a predetermined threshold value, and so that the value of the gross output power becomes equal to the above described threshold value when the value of the total load power is greater than the threshold value.

A ramping subsystem of a control system for a dual path electronically controlled hydrostatic transmission is used to modify the commanded rate of change of pump and motor acceleration, deceleration and direction change command (performed to command machine motion from forward to reverse or vice versa) in order to achieve desired machine performance and operator feel. Pump and motor acceleration, deceleration and direction change command rates are then further modified using scaling tables based on selected maximum machine speed using operator input device.

A hydraulic control device for a forklift includes a hydraulic pump, a single electric motor for driving the hydraulic pump, an outflow control mechanism provided between a lift cylinder and the hydraulic pump, a flow control valve provided between the outflow control mechanism and a draining portion, and a controller. When a lowering operation of a fork and either forward or rearward mast tilting operations of a mast are performed at the same time, the controller controls the electric motor based on a target speed of the hydraulic pump. The flow control valve controls the flow rate of hydraulic fluid from the lift cylinder to the hydraulic pump and the flow rate from the lift cylinder to the draining portion in accordance with the difference between the actual rotation speed of the hydraulic pump and the target rotation speed of the hydraulic pump.

This invention is a hydraulic work machine having an electric assist motor coupled to an engine and a hydraulic pump, in the hydraulic work machine of which, a rotational speed and torque of the engine are controlled so that an operating point of the engine moves along a predetermined route for yielding a combustion state of the engine under a transient state that the engine changes in speed and torque. A target speed and torque of the engine 7 are set so that the rotational speed and torque of the engine 7 will change along a predetermined route F in a running region of the engine, respective rates of change of the target rotational speed and torque of the engine 7 are limited, and the engine 7 is controlled to yield the target engine speed. In addition, torque of the assist motor 10 is controlled to yield the target torque of the engine.

A hydraulic system is adapted to provide at least one of a fluid flow at a variable fluid pressure or a fluid flow at a variable fluid displacement. A pressure sensor measures a fluid pressure. A controller is in communication with the engine and the pressure sensor. Wherein, the controller sends an engine speed signal to operate the engine in an open state and controls the fluid displacement or the fluid pressure of the hydraulic system to a first load condition. Further wherein, the controller detects an engine speed and a fluid pressure of the hydraulic system with the pressure sensor when the engine is in the open state and the hydraulic system is in the first load condition. Further wherein, the controller operably calculates a total engine torque as a function of the detected engine speed and fluid pressure when the hydraulic system is in the first load condition.