Hitachi Construction Machinery Co., Ltd.

Shohei Kamiya

Hiroyuki Adachi

Kazunori Nakamura

Yasushi Arai

Hidenobu Tsukada

Kouji Ishikawa

Kazuhiro Shibamori

Tomoyuki Saito

Masanori Ezawa

Taku Kashu

Tsuyoshi Nakamura

Hiroyuki Kamata

Yoichi Kowatari

Toshihiro Abe

Yutaka Watanabe

Hideki Haramoto

Kensuke Sato

Hiroki Sugawara

Toshinori Fujii

Hidenori Mano

Kazuki Kubota

Masashi Shoji

In order to purify NOx in exhaust gas discharged from an engine, a urea water supply system is configured by a urea water injection valve, a urea water tank, urea water supply piping () and a urea water supply device (). Cooling water piping () that allows cooling water of the engine to flow through is laid along the urea water supply piping (), while the cooling water piping () is connected to the urea water supply device () at a connection portion () of an inflow pipe and a connection portion () of an outflow pipe, and a part () of the inflow pipe is installed to be close to connection portions () of the urea water supply piping () to the urea water supply device () within a predetermined distance range in which heat of the cooling water reaches the connection portions.

Urea water supply system for construction machine

Front and rear side flange portions of a filter accommodating cylinder are provided with positioning pins. A flange portion of an upstream cylinder is provided with a notched groove and a flange portion of a downstream cylinder is provided with a notched groove. In consequence, when the filter accommodating cylinder is connected between the upstream cylinder and the downstream cylinder, each of the positioning pins disposed at the front and rear flange portions is engaged with each notched groove of the upstream cylinder and the downstream cylinder. The filter accommodating cylinder can be positioned to be coaxial with the upstream cylinder and the downstream cylinder. As a result, after performing a cleaning operation to a DPF, an operation of once again connecting the filter accommodating cylinder between the upstream cylinder and the downstream cylinder can be quickly and easily performed.

Exhaust gas treatment device

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

An engine powered machine is provided with a high-performance exhaust gas purification system and is capable of promptly raising a temperature of an operator's cab to a comfortable temperature. The exhaust gas purification system that makes use of an NOx removal catalyst and a reducing agent is provided with a reducing agent heater for heating a reducing agent, which is stored in a reducing agent tank, with heat of an engine cooling medium and an on/off device for controlling an introduction of the engine cooling medium into the reducing agent heater. When a temperature of the engine cooling medium is higher than a first predetermined temperature, a temperature of the reducing agent in the tank is lower than a second predetermined temperature and a temperature in an operator's cab is lower than a third predetermined temperature, a controller switches the on/off device into a closed state to increase a flow rate of the engine cooling medium to be guided to a heat exchanger of a heating apparatus.

Engine powered 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

A mounting structure is provided for an NOx reduction system for a hydraulic excavator. The NOx reduction system includes a PM collection filter to be arranged in an exhaust passage of an engine to collect suspended particulate matter in exhaust gas from the engine, a urea SCR catalyst for reducing and purifying nitrogen oxides in the exhaust gas from the engine, a urea water spay device for spraying a urea water into the exhaust passage of the engine, a urea water feeder for feeding the urea water to the urea water spray device, and a urea water storage tank for storing therein the urea water to be guided to the urea water feeder. In the mounting structure, the counterweight is provided with a recessed section formed therein, the urea SCR catalyst is arranged in the recessed section, and the PM collection filter is arranged in the engine compartment. The urea SCR catalyst and PM collection filter are arranged to form an 'L' pattern.

Mounting structure for NOx reduction device for construction machine

A support member () is provided on a cylindrical member () of an upstream cylinder (). A connector portion (C) of a first temperature detector () for detecting the temperature of exhaust gas flowing into an oxidation catalyst (), a connector portion (C) of a second temperature detector () for detecting the temperature of the exhaust gas flowing into a particulate matter removing filter (), and a sensor portion (A) of a pressure detector () for detecting the front and rear pressures of the particulate matter removing filter () are arranged to be mounted on this support member (). Accordingly, the support member () is capable of supporting the connector portions (C,C) of the temperature detectors () and the sensor portion (A) of the pressure detector () in one location in a concentrated manner, so that harnesses on a controller side can be easily connected thereto.

Exhaust gas purifying device

A mounting structure for an NOx reduction system for a construction machine is provided for relaxing restrictions on a space for the arrangement of the NOx reduction system. The mounting structure includes a urea-water SCR catalyst for reducing and purifying nitrogen oxides emitted from an engine, a urea water spray device for spraying urea water into an exhaust passage of the engine, a urea water feeder for feeding the urea water to the urea water spray device, a first urea-water tank and second urea-water tank for storing the urea water to be guided to the urea water feeder, and a controller for controlling drive of the urea water spray device and urea water feeder. A counterweight is provided with a cavity formed therein, the urea water feeder, first urea-water tank, second urea-water tank and controller are integrally arranged as an assembly arranged in the cavity of the counterweight.

An exhaust gas treatment filter removes particulate matter from exhaust gas of a diesel engine. The particulate matter which accumulates on the filter is removed by a manual regeneration system that can simply be controlled. After a manual regeneration switchis shifted to an ON-position, a load control sectionkeeps at least one of the revolution speed N of an engine, the displacement volume q and discharge pressure P of a hydraulic pressure pumpat a corresponding first target value (N, q, or P) or second target value (N, q, or P) depending on a temperature of the cooling water in relation to a flame-out prevention temperature T. A regeneration control sectionstarts the compulsory regeneration after the manual regeneration switch has been shifted to the ON-position and when the cooling water temperature is equal to or higher than T

Working machine

Disclosed is a working machine capable of preventing damage to a filter due to excessive accumulation of particulate matter (PM), even under a situation that requires, prior to compulsory regeneration of the filter, moving the machine to a place in which to perform the regeneration work. The working machine that includes an exhaust treatment devicehaving a filterto trap the PM, a regeneration control sectionfor compulsorily regenerating the filter, and a regeneration instruction devicefor instructing the regeneration control sectionto start the compulsory regeneration. Further, when a deposition quantity estimating element determines that an actual PM deposition quantity has reached a deposition alarm level, an alarm devicenotifies an operator that the time has come to start the movement of the working machine to the place of regeneration.

Before a large amount of PM is deposited in a filter, an exhaust gas cleaning system for a construction machine regenerates the filter. In a non-operational state with the engineof the construction machine left running for a certain time, a controllermonitors the non-operational state. After this state continues for a predetermined time Ta, when the pressure sensed by a differential pressure sensoris higher than a second predetermined pressure level P, the controllercontrols the rotating speed of the engineto a predetermined speed Na before starting forced regeneration to burn off the PM deposited in a filter. When the pressure sensed by the differential pressure sensordecreases below a first predetermined pressure level P, the controllerterminates the regeneration automatically and returns the engine to normal control mode.

Exhaust gas cleaning system for construction machine

Each time a starting process for a diesel engineis conducted and before the diesel engineis started, any differences of the pressures Pand Pdetected by first and second pressure sensorsand, respectively, with respect to a predetermined reference pressure value Pref, are computed and stored as first and second correction values &#x394;Pand &#x394;P, and then a differential pressure Pacross a particulate filter in the diesel engineis computed using the pressure detection results of the first and second pressure sensorsand the first and second correction values &#x394;P, &#x394;P. Thus, use of simply constructed and highly durable sensors during the detection of the differential pressure existing across the filter allows accurate measurement of this differential pressure.

Exhaust gas cleaning system for diesel engine

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.

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Kasumigaura, Japan

Shohei Kamiya