Hitachi Construction Machinery Co., Ltd.

Yasushi Arai

Kazunori Nakamura

Shohei Kamiya

Kouji Ishikawa

Yoichi Kowatari

Hidenobu Tsukada

Hideo Karasawa

Hideki Haramoto

Taku Kashu

Toichi Hirata

Hiroshi Watanabe

Tsuyoshi Nakamura

Yoshinori Furuno

Nobuei Ariga

Yuuki Gotou

Gen Yasuda

Kentaro Itoga

Masanori Ezawa

Shouhei Kamiya

Motoyuki Yabuuchi

Takashi Hirose

Gen Tsukuba-Ryo 4-1 Yasuda

A hydraulic drive system for a hydraulic working machine sets a delivery pressure at a preset value upon raising a temperature of exhaust gas to a temperature needed for combustion of particulate matter by increasing a load to be applied to an engine. In a non-operation state, a variable restrictor is controlled by a controller and a delivery pressure control valve to increase a delivery pressure of a variable displacement hydraulic pump, so that the load is increased to raise the temperature of exhaust gas to the temperature needed for the particulate matter combustion. At this time, the controller controls the delivery pressure control valve such that a delivery pressure to be detected by a delivery pressure sensor will conform with a preset reference delivery pressure. The reference delivery pressure is set to a minimum pressure that can provide the exhaust gas with combustion heat.

Hydraulic drive device of hydraulic operating machine

A fuel tank () is constructed such that a front flange portion (A) of a top surface plate (A) of a second plate () extends outside in relation to a front surface plate (B) of a first plate (). As a result, a front surplus space (A) projected in the upper and lower directions in a range of the front flange portion (A) of the top surface plate is formed in the front surface side of the front surface plate. A urea water tank () is arranged along the fuel tank () in such a manner that a rear side portion thereof enters into the front surplus space. Therefore, the rear side portion of the urea water tank can enter into the front surplus space using the front surplus space formed in the fuel tank (), thereby increasing the tank capacity without downsizing the article accommodating box ().

Construction machine

A urea water tank () is arranged in a cab () at which an operator boards, thereby making it possible to arrange urea water under a preferred temperature environment for preventing freeze and crystallization of the urea water. A water supply port (A) is provided to be opened to a left surface portion (C) of a cab box () constituting the cab () for supplying the urea water to the urea water tank () from an outside of the cab (). Therefore, even in a case of resupplying the urea water to the urea water tank (), an operator can easily resupply the urea water through a water supply hose () to the urea water tank () from the outside of the cab () without entering into the cab ().

An exhaust gas purification system for an engineering machine is capable of avoiding decreases in working efficiency during regeneration control by burning off a deposit of particulate matter from a filter efficiently during a work pause time. An operating sectionof a display monitoris used to set a work pause time and a work pause switchnotifies a vehicle body control unitthat the hydraulic excavator has entered a work pause state. In response, the vehicle body control unitcalculates the time required for a regenerating device to burn off the current amount of particulate matter deposited on the filter, and when the calculated time is longer than the preset work pause time, a regeneration controllerof an engine control unitis activated, and a solenoid control valveis switched to a closed position during the preset work pause time.

Exhaust gas purification system for engineering machine

An exhaust gas treatment apparatus for a working machine is provided to reliably prevent a specific process that raises the exhaust temperature of an exhaust gas treatment section from being carried out during switching operation of a directional control valve. The apparatus includes: a directional control valve that controls the flow of pressure oil supplied to an actuator; a pilot pump that supplies pressure oil to an operating device operated to switch the directional control valve; an open/close valve arranged downstream of the directional control valve; a control valve that controls the open/close valve; a lock valve arranged between the pilot pump and the operating device; a detecting section that detects when a specific process that raises the exhaust temperature of an exhaust gas treatment section becomes necessary, and outputs the corresponding detection signal; a controller that controls the control valve; and a pipe for performing a process of setting the open/close valve to an open position in accordance with the pilot pressure oil supplied from the pilot pump.

Exhaust gas treatment apparatus for working machine

An upstream cylinder () and a downstream cylinder () are fixedly mounted to a support member (), and a filter cylinder () is provided mountably and dismountably between the cylinders () and (). In consequence, only the filter cylinder () can be dismounted with the cylinders () and () left as they are on the support member (), so that the maintenance operation of a particulate matter removing filter () can be performed easily. In addition, pressure conduits () and () and a pressure sensor () of a pressure detection unit () for detecting a clogged state of the particulate matter removing filter () are disposed at positions offset from a moving path () of the filter cylinder (). In consequence, only the filter cylinder () can be easily mounted or dismounted without being obstructed by the pressure conduits () and () and the pressure sensor ().

A construction machine includes a front working implement operable as a result of driving of an engine, a urea SCR catalyst arranged in an exhaust gas line from the engine to purify and reduce nitrogen oxides in exhaust gas, an aqueous urea solution tank for storing an aqueous urea solution, a temperature detector for detecting a temperature of the aqueous urea solution, an air conditioner for air-conditioning an operator's cab, and a warm/cold air guiding device for guiding warm/cold air, which has been blown out of the air conditioner, to the aqueous urea solution tank in accordance with the temperature of the aqueous urea solution. The warm/cold air guiding device includes a controller for outputting a warm air control signal or cold air control signal, which corresponds to a temperature of the warm/cold air blown out of the air conditioner.

An engine lag down control system for construction machinery has a machinery body controller having first, second and third torque control units and a solenoid valve. The first torque control unit controls a torque control valve to a minimum pump torque corresponding to a target number of engine revolutions when a non-operated state of a control device has continued beyond a monitoring time. The second torque control unit controls the torque control valve such that the above-described minimum pump torque is held for a predetermined holding time subsequent to the operation of the control device from the non-operated state. The third torque control unit controls the torque control valve such that from a time point of a lapse of the predetermined holding time, the pump torque is gradually increased on a basis of a predetermined torque increment rate.

Engine lag down suppressing device of construction machinery

A ureal water tank (), a storage of an aqueous urea solution, is located within a utility room (G) in a right front section of a revolving frame (), which is readily accessible from outside. In this instance, among a plurality of operating oil conduits (), a working mechanism operating conduit () which supplies operating oil to a boom cylinder (D) of a working mechanism () is arranged to run along exterior surfaces of the ureal water tank (). Therefore, even if the ureal water tank () is located in a place with no heat source, the aqueous urea solution in the ureal water tank () can be stably kept in a heated state by utilization of heat of operating oil in circulation through the working mechanism operating conduit ().

Automotive construction machine

A current load rate of an engineis computed and a maximum absorption torque of at least one hydraulic pumpis controlled so that the load rate is held at a target value. Engine stalling can be prevented by decreasing the maximum absorption torque of the hydraulic pump under a high-load condition. When an engine output lowers due to environmental changes, the use of poor fuel or other reasons, the maximum absorption torque of the hydraulic pump can be decreased without a lowering of the engine revolution speed. Further, the present invention is adaptable for any kinds of factors causing a lowering of the engine output, such as those factors that cannot be predicted in advance or are difficult to detect by sensors. In addition, because of no necessity of sensors, such as environment sensors, the manufacturing cost can be reduced.

Method and device for controlling pump torque for hydraulic construction machine

[PROBLEM] To provide a construction machine capable of performing necessary operation or operations without a difficulty even when a remaining amount of a reducing agent becomes small. [SOLUTION] In a hydraulic excavator having an engine, a hydraulic cylinder (), plural actuators including a hydraulic motor (), and an exhaust gas treatment system for subjecting, to purification treatment, nitrogen oxides in exhaust gas from the engine, the hydraulic excavator is provided with an actuator operation control means for performing, when the remaining amount of the reducing agent in a reducing agent storage tank () is detected by a remaining reducing-agent amount detector () to have become equal to or smaller than a predetermined remaining amount, limiting control to limit an operation of the hydraulic cylinder () such that a front working implement driven by the hydraulic cylinder () becomes difficult to exhibit its function, and at a same time, holding control for holding the hydraulic motor () operable such that a function of a travel base () or swing upperstructure () driven by the hydraulic motor () can be exhibited.

An engine control system includes pressure sensors (), position sensors (), pressure sensors (), a target revolution speed modification value computing unit (), and a modification value adder (). A target revolution speed NRfor use in control is computed based on changes of status variables such that the target revolution speed NRincreases from the target revolution speed NRapplied from an input unit (), and then moderately returns to the target revolution speed NR. In accordance with the computed target revolution speed NRfor use in control, a target fuel injection amount FNis computed and a fuel injection amount is controlled. As a result, a drop of an engine revolution speed attributable to an abrupt increase of an engine load can be suppressed without sacrificing the work efficiency, and lowering of durability caused by an excessive increase of the engine revolution speed can be prevented.

Engine control system for construction machine

A machine body controllerA includes a modification control unitAb for computing a torque modification value based on detected signals from environment sensorstoand modifies a maximum absorption torque of a hydraulic pump controlled by a basic control unitAa. An engine controllerB includes a modification control unitBb for computing an injection modification value based on detected the signals from the environment sensorstoand modifies a fuel injection state of a fuel injection devicecontrolled by a basic control unitBa. The controllersA,B further include computation element altering unitsA communication controllerC downloads alteration data obtained from an external terminalto the computation element altering unitswhereby corresponding computation elements contained in the modification control unitsAb,Bb are altered. As a result, it is possible in any environments to approprately modify the maximum absorption torque of the hydraulic pump and the fuel injection state of the injection device, and to sufficiently develop the performance of a construction machine.

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Tsuchiura, Japan

Yasushi Arai