Abstract: An exhaust gas cleaning system comprises a reducing agent injection module installed in an housing mounted in an exhaust pipe through which an exhaust gas is discharged, the reducing agent injection module being configured to inject a reducing agent into the housing, a selective catalyst reduction device installed in rear of the reducing agent injection module and configured to catalytic react the reducing agent with nitrogen oxide included in the exhaust gas to reduce the nitrogen oxide, a differential pressure sensor to detect a differential pressure between a pressure in the housing in front of the selective catalyst reduction device and a pressure of the housing in rear of the selective catalyst reduction device, and a control device to receive the pressure information from the differential pressure sensor and to output a first warning signal when the detected differential pressure is lower than a predetermined pressure.

Abstract: In a method of controlling a main control valve in construction machinery, a first joystick signal for controlling a first control valve device and/or a second joystick signal for controlling a second control valve device are received from one joystick. While one of the first and second control valve devices operates, whether or not a joystick signal for controlling another of the first and second control valve devices is inputted is determined. A weighted value is applied to a threshold of valve operation initiation with respect to a joystick displacement to determine a raised threshold of valve operation initiation. If the inputted joystick displacement satisfies the raised threshold of valve operation initiation, a valve stoke corresponding to the inputted joystick displacement is calculated and outputted.

Abstract: The present disclosure relates to a wheel driving device and a wheel driving method for a hybrid construction machine, in which in a construction machine having wheels, particularly, a hybrid wheel loader, by small-capacity low-speed electric motors, small-capacity high-speed electric motors, transmissions each having a clutch, and a control unit which are installed for all of the wheels each, the wheel driving device drives the low-speed electric motor during low-speed driving and drives the high-speed electric motor during high-speed driving by turning on and off the clutch during the low-speed driving and the high-speed driving, thereby reducing manufacturing costs of the wheel driving device, improving fuel economy of the construction machine, reducing abrasion of tires mounted on the wheels, improving durability of the tires, and ensuring traveling stability.

Abstract: A control system for construction machinery, includes a hydraulic pump, first and second actuators connected to the hydraulic pump through first and second parallel lines respectively, first and second control valves installed in the first and second parallel lines respectively and configured to control operations of the first and second actuators, first and second spool displacement adjusting valves configured to control displacement amounts of the spools of the first and second control valves, and a controller configured to output a control signal to the first and second spool displacement adjusting valves corresponding to a manipulation signal of an operator, and configured to limit a spool displacement amount of the second control valve according to the manipulation signal for the first actuator when the manipulation signal for a multiple operation of the first and second actuators is received.

Abstract: An apparatus for controlling an EGR valve, includes: a measurement unit to measure at least one operation condition of an engine system; a fresh air amount setting unit to set a target amount of fresh air based on the operation condition; a fresh air amount sensor to measure a current amount of fresh air introduced through an intake line; a control calculation unit to set a signal for controlling an opening degree of the EGR valve so that the current amount of fresh air follows the target amount of fresh air; and an identifier to simulate an input and an output of the engine system, and output engine system input-output sensitivity which is a ratio of a change rate of the current amount of fresh air to a change rate of the opening degree of the EGR valve.

Abstract: Disclosed are a construction machine such as an excavator having a hydraulic system and a method for controlling the construction machine. The construction machine includes: a hydraulic pump which is operated by a driving source to supply a working fluid; an actuator which operates by being supplied with the working fluid from the hydraulic pump; a spool which controls a flow of the working fluid supplied to the actuator from the hydraulic pump; an operating unit which controls an operation of the actuator; a memory unit which stores at least two operating speed profiles for the actuator; an operating speed selecting unit which selects any one of the at least two operating speed profiles stored in the memory unit; and a control unit which controls a discharge flow rate of the hydraulic pump based on the operating speed profile selected by the operating speed selecting unit.

Abstract: The present invention relates to control of an opening degree of an exhaust gas recirculation (EGR) valve which is provided in an engine which uses compressed natural gas as fuel. A method for controlling an EGR valve of an engine according to the present invention includes: calculating the amount of exhaust gas to be transferred from an exhaust line to an intake line according to engine operating conditions; regulating an opening degree of an EGR valve based on the calculated amount of exhaust gas; measuring a temperature of exhaust gas discharged from a combustion chamber; and increasing the opening degree of the EGR valve by a preset increment when the temperature of the exhaust gas discharged from the combustion chamber exceeds a preset reference temperature.

Abstract: Heat resistant spheroidal graphite cast iron having an improved high temperature tensile strength includes carbon (C) in a range of 3.2-3.4 wt %, silicon (Si) in a range of 4.3-4.8 wt %, manganese (Mn) in a range of 0.2-0.3 wt %, molybdenum (Mo) in a range of 0.8-1.0 wt %, vanadium (V) in a range of 0.4-0.6 wt %, chrome (Cr) in a range of 0.2-0.4 wt %, niobium (Nb) in a range of 0.2-0.4 wt %, inevitable impurities, and a remainder of iron (Fe) based on a total weight of the heat resistant spheroidal graphite cast iron. The heat resistant spheroidal graphite cast iron further includes barium (Ba) in a range of 0.0045-0.0075 wt %. A content ratio of chrome (Cr) and barium (Ba) (Cr/Ba) is in a range from about 26 to about 89.

Abstract: A selective catalytic reduction system includes a reducing agent injection module installed in an exhaust pipe through which an exhaust gas is discharged from an engine and configured to inject a reducing agent into the exhaust pipe, a temperature calculator configured to calculate a temperature of the reducing agent injection module using temperature-related information of the reducing agent injection module, and a temperature controller configured to control to increase a reducing agent injection amount of the reducing agent injection module when the calculated temperature.

Abstract: A wheel driving system includes a generator connected to an engine and configured to generate electrical energy, a front axle configured to drive a front wheel and including a front electric motor configured to produce a driving torque and a front transmission configured to convert the driving torque into a conversion torque and transmit the conversion torque to the front wheel via a front drive shaft, a rear axle configured to drive a rear wheel and including a rear electric motor configured to produce a driving torque and a rear transmission configured to convert the driving torque into a conversion torque and transmit the conversion torque to the rear wheel via a rear drive shaft, and a central connection unit operatively connected to the front drive shaft and the rear drive shaft and configured to transmit the conversion torque between the front axle and the rear axle.

Abstract: The present disclosure relates to a hydraulic system of construction machinery and a method of controlling the hydraulic system. The hydraulic system of construction machinery and the method of controlling the hydraulic system according to the present disclosure assign a weighted value for each operation, preliminarily distribute a (available torque that can be used) value that an engine can provide, through torque weighted values for each operation, and calculate surplus torque and deficient torque by comparing a preliminary distributable torque value to required torque. The surplus torque is provided for an operation in which torque is deemed to be deficient. Thus, the hydraulic system of construction machinery and the method of controlling the hydraulic system according to the present disclosure can sufficiently use available torque that can be used so that an operator can achieve a desired level of performance during the operation.

Abstract: The present disclosure relates to an engine control device for hybrid construction machinery, and more particularly, and an object of the present disclosure is to, in a hybrid excavator, in which a swing apparatus is electrically driven by being separated from a hydraulic power train system in the related art, satisfy a minimum rotational speed of an engine auxiliary motor which is necessary to satisfy a target charging amount required for an energy storage device, and improve fuel efficiency by removing unnecessary energy loss at low loads by controlling a rotational speed of an engine to be lower than a rotational speed of an engine determined based on a dial input and a mode input in the related art, in a case where a target power generation amount of the engine auxiliary motor is small in a low-load work situation.

Abstract: The present disclosure relates to a method, a device, and a system for controlling a hydraulic pump of a construction machine, the system comprising: an engine; an engine control unit configured to control the engine by using engine limit torque information and current engine torque information of the engine; a hydraulic pump operated by power supplied from the engine; at least one actuator driven by a hydraulic pressure discharged from the hydraulic pump; and a hydraulic pump control device configured to control a limited swash plate angle of the hydraulic pump by using a torque of the hydraulic pump and the engine limit torque information received from the engine control unit.

Abstract: The present disclosure relates to a closed circuit hydraulic system for a construction machine including a plurality of actuators and a plurality of hydraulic pumps selectively supplying working oil to the plurality of actuators bidirectionally and the closed circuit hydraulic system includes: a charge line selectively connected with a low-pressure side hydraulic line which returns to the hydraulic pump from the actuator among hydraulic lines connecting the hydraulic pumps and the actuators; a charge pump supplying a supplement flow to the charge line; and a variable relief valve selectively changing a normal mode to limit a pressure of the charge line to a predetermined pressure or less and a boost mode to limit the pressure of the charge line to a pressure lower than the pressure of the charge line in the normal mode.

Abstract: The present disclosure provides a pressure peak reduction valve for an excavator. The pressure peak reduction valve includes at least: a poppet seat which has an inlet port, and at least one communication hole which communicates with a hydraulic tank and is formed in an outer circumferential surface of the poppet seat; a main poppet which slides in the poppet seat; a poppet spring which is provided in the main poppet; a valve seat which has one end portion inserted into the main poppet so as to be in contact with one end portion of the poppet spring; a cone which is provided to be inserted into an openable hole formed at an end portion of the valve seat; an adjustment screw which is provided in the valve seat; and a piston which slides in the adjustment screw.

Abstract: The present disclosure relates to a control circuit and a control method for boom energy regeneration, and the control circuit for boom energy regeneration includes: a control unit which controls a discharge amount control valve, such that the amount of oil, which is discharged from a head of a boom cylinder, is supplied to a regeneration device or a rod of the boom cylinder through a hydraulic regeneration line, and when the regeneration device has an abnormality, the amount of oil, which is discharged from the head of the boom cylinder, is supplied to the main control valve through a hydraulic discharge line.

Abstract: A control system for construction machinery includes first and second hydraulic pumps connected to an engine, a swing control valve and a first boom control valve installed in a first center bypass line connected to the first hydraulic pump, a second boom control valve installed in a second center bypass line connected to the second hydraulic pump, a shutoff valve installed in a control line through which a boom raising pilot signal pressure is supplied to the first boom control valve and configured to selectively open and close the control line, and a control unit configured to electronically control the shutoff valve according to a manipulation signal, wherein the control unit closes the shutoff valve such that the first boom control valve is shifted to a neutral position when a swing operation priority mode is selected.

Abstract: A hydraulic control apparatus for construction machinery, includes an accumulator to accumulate a high-pressure hydraulic oil discharged from a boom cylinder for driving a boom of the construction machinery, a hydraulic pump connected to the accumulator and driven by the high-pressure hydraulic oil, a pressure sensor configured to detect a pressure of the accumulator, and a control unit connected to the accumulator and the hydraulic motor and configured to control operations of the accumulator and the hydraulic motor, and having a determiner that receives a pressure value of the accumulator and number of revolution of the hydraulic motor to determine whether or not the hydraulic motor fails when the hydraulic oil accumulated in the accumulator is supplied to the hydraulic motor.

Abstract: A hydraulic system for construction machinery includes a boom cylinder, a main control valve including a boom control spool that is configured to selectively supply a hydraulic oil from a hydraulic pump to a boom head chamber and a boom rod chamber of the boom cylinder, a regeneration device connected to the boom head chamber of the boom cylinder through a hydraulic regeneration line, a regeneration valve unit installed in the regeneration line, and a control unit connected to the main control valve and the regeneration valve unit, wherein in a boom down low speed mode the hydraulic oil is drained through the regeneration device to lower the boom at a first speed, and in a boom down high speed mode the hydraulic oil is drained through the regeneration device and the main control valve to lower the boom at a second speed greater than the first speed.