Hitachi Construction Machinery Co., Ltd.

Junji Yamamoto

Tsutomu Udagawa

Shigeyuki Sakurai

Yukihito Suzuki

Masatoshi Hoshino

Seiji Ishida

Shiro Yamaoka

Kazuo Fujishima

Yusuke Kajita

Takashi Okada

Hidenobu Tsukada

Mitsuo Sonoda

Akira Nakayama

Atsushi Kanda

He Bao

A cost required to perform the diagnosis of the degradation such as a reduction in output power of an engine while engine degradation diagnosis accuracy is improved. To this end, a controller(engine diagnosing device) determines whether a hydraulic pumpis in a preset loaded state (an operation scene where a load torque of the hydraulic pumpis in a stable state) for acquiring diagnosis data of an engine, and validates a controlled variable related to a torque command value Ta of speed sensing control as the diagnosis data of the enginewhen it is determined that the hydraulic pumpis in the present loaded state, generates time history data using this validated controlled variable as a current feature variable, and enables this time history data to be displayed as trend data for engine diagnosis on a display device

Construction machine

There is provided a construction machine that is capable of measuring a minute leakage flow rate of a one-sided tilting variable displacement hydraulic pump. The construction machine includes a pressure sensor that detects a pressure of a hydraulic pump, a bleed-off adjusting device that is enabled to adjust a bleed-off flow rate of the hydraulic pump, and an input device that gives an instruction for measurement of a leakage flow rate of the hydraulic pump. The controller is configured to measure, when the controller determines that the operation device is in a non-operated state and when a measuring command is inputted from the input device, a pressure of the hydraulic pump while changing a control command value for the bleed-off adjusting device in a state in which a flow rate of the hydraulic pump is maintained, and calculate the leakage flow rate of the hydraulic pump on the basis of the control command value for the bleed-off adjusting device at the time that the pressure of the hydraulic pump is stabilized at a predetermined pressure.

Each time clogging of a filter () of an air cleaner is determined on the basis of intake negative pressure of an engine (), and the air filter () is cleaned, an accumulated value of operating time of the engine () from previous cleaning until clogging is determined is taken as a cleaning interval (S), and sequentially measured. A plurality of stages are previously set by classifying a minimum value and a maximum value of the cleaning interval (S), and the measured cleaning interval (S) is added to the stage to which the measured cleaning interval (S) is to belong, among the stages. A histogram in which an axis of abscissas is taken as the stage, an axis of ordinates is taken as frequency of the cleaning interval (S) is constructed, and an approximate straight line (L) illustrated by a solid line is obtained by approximating a characteristic line (L) of the histogram illustrated by a dotted line to a straight line. A characteristic of the histogram is changed as the deterioration of the air filter () progresses, and when a slope of the approximate straight line (L) based on the characteristic gradually decreases from right-upward slop illustrated by a thin line, exceeds (ΔY/ΔX=0) equivalent to the horizontal, deterioration of the air filter is determined.

Air filter deterioration determination device of construction machine

A hydraulic working machine has an assist electric motor connected to an engine and a hydraulic pump. The emissions of air pollutants in the exhaust gas from the engine are minimized regardless of fluctuations in the load torque of the hydraulic pump. A specific revolution speed suitable for reducing the emissions of air pollutants is stored, and an engine is controlled using the specific revolution speed as a target revolution speed. The absorption torque of a hydraulic pump is subjected to high-pass filtering whereby a high-frequency component devoid of a trend component is obtained. Target assist torque is computed from the high-frequency component, and the assist electric motor is subjected to power running/generation control accordingly. A specific output torque range suitable for reducing the emissions of air pollutants is stored, and the target assist torque is corrected so that the trend component does not exceed the specific output torque range.

Hydraulic working machine

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Kasumigaura, Japan

Junji Yamamoto