Abstract: Each time a starting process for a diesel engine 2 is conducted and before the diesel engine 2 is started, any differences of the pressures P1 and P2 detected by first and second pressure sensors 21 and 22, respectively, with respect to a predetermined reference pressure value Pref, are computed and stored as first and second correction values ?P1 and ?P2, and then a differential pressure P12 across a particulate filter in the diesel engine 2 is computed using the pressure detection results of the first and second pressure sensors 21, 22 and the first and second correction values ?P1, ?P2. 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.

Abstract: 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.

Abstract: Before a large amount of PM is deposited in a filter 32, an exhaust gas cleaning system for a construction machine regenerates the filter to avoid a decrease in output due to the exhaust gas pressure rise occurring immediately before the filter is regenerated, and to reduce the likelihood of unusual increases in the internal temperature of the filter due to the combustion of the PM, associated with the execution of the regeneration, and consequential thermal damage to the filter. If a value of a differential pressure across the filter 32 is greater than a predetermined pressure, a controller 4 conducts engine speed control to a predetermined rotating speed Na suitable for the regeneration, then enters forced regeneration automatically, and burns off the PM. When the sensed differential pressure decreases below a predetermined pressure, the regeneration is terminated automatically and the engine 1 is stopped.

Abstract: Disclosed is an exhaust gas purification system for a working machine. The system is provided with a filter for capturing particulate matter contained in exhaust gas from an engine, a differential pressure sensor for detecting a differential pressure between an exhaust upstream side and an exhaust downstream side of the filter, and a controller having a regeneration determination unit for determining whether or not a time, at which forced regeneration is needed, has been reached. The controller includes one that has a variation determination unit for determining whether or not a state quantity relevant to an operation of the engine, for example, an engine speed has varied abruptly and that, when the state quantity is determined to have abruptly varied, performs processing to invalidate the determination by the regeneration determination unit during a predetermined time in which an effect of the state quantity is considered to diminish.

Abstract: 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.

Abstract: A ureal water tank (28), a storage of an aqueous urea solution, is located within a utility room (6G) in a right front section of a revolving frame (6), which is readily accessible from outside. In this instance, among a plurality of operating oil conduits (18), a working mechanism operating conduit (21) which supplies operating oil to a boom cylinder (5D) of a working mechanism (5) is arranged to run along exterior surfaces of the ureal water tank (28). Therefore, even if the ureal water tank (28) is located in a place with no heat source, the aqueous urea solution in the ureal water tank (28) can be stably kept in a heated state by utilization of heat of operating oil in circulation through the working mechanism operating conduit (21).

Abstract: An exhaust gas cleaning system for an engineering vehicle, such as a hydraulic excavator, is capable of performing manual regeneration control of a regeneration fuel injector 40 that is started only under the following conditions: a manual regeneration starting switch 39 is enabled; an engine control dial 2 commands a low-speed idle revolution speed; and a gate lock lever 22 is switched to a second position B at which generation of control pilot pressures a through f by use of remote control valves 25, 26, and 27 is disabled. Even when the manual regeneration control is being executed, if the gate lock lever 22 is switched to a first position A, the manual regeneration control immediately ends. As a result, the manual regeneration control of a filter for collecting particulate matter included in the exhaust gas and the operation of the work system do not influence each other.

Abstract: A fuel tank (12) is constructed such that a front flange portion (14A1) of a top surface plate (14A) of a second plate (14) extends outside in relation to a front surface plate (13B) of a first plate (13). As a result, a front surplus space (15A) projected in the upper and lower directions in a range of the front flange portion (14A1) of the top surface plate is formed in the front surface side of the front surface plate. A urea water tank (24) is arranged along the fuel tank (12) in such a manner that a rear side portion thereof enters into the front surplus space portion. 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 (12), thereby increasing the tank capacity without downsizing the article accommodating box (16).

Abstract: A urea water tank (23) is arranged in a cab (10) 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 (24A) is provided to be opened to a left surface portion (19C) of a cab box (19) constituting the cab (10) for supplying the urea water to the urea water tank (23) from an outside of the cab (10). Therefore, even in a case of resupplying the urea water to the urea water tank (23), an operator can easily resupply the urea water through a water supply hose (24) to the urea water tank (23) from the outside of the cab (10) without entering into the cab (10).

Abstract: An exhaust gas cleaning system is provided in an engineering vehicle such as a hydraulic excavator. During automatic regeneration, when a gate lock lever 5 is in a locked state and work is not performed, the exhaust gas temperature detected by the exhaust temperature detecting device 37 may be lower than the threshold value, so temperature-rising assistance is started as follows. The minimum engine output PS1 (pump discharge pressure P1 and pump discharge amount Q1) is brought to engine output PS2 (pump discharge pressure P2 and pump discharge amount Q2). In this way, a hydraulic load is applied to an engine to thereby increase exhaust gas temperature. When the work is resumed during the regeneration, an operator pulls down the gate lock lever to the first position A, and the engine output is returned to PS1. Thus, the temperature-rising assistance is stopped, however the automatic regeneration is continued.

Abstract: [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.

Abstract: An exhaust gas post-treatment system for a vehicle is provided, which in the course of regeneration ascertains whether or not there is any object approaching a body of the vehicle from behind. A filter is arranged in an exhaust passage of an engine to trap PM therein. A trapped and deposited PM amount sensing device senses a deposited amount of PM deposited in the filter. A fuel injector burns and removes PM deposited in the filter to conduct regeneration of the filter. A rearward monitoring camera monitors a scene rearward of a vehicle body. A display module displays monitoring information from the rearward monitoring camera, and a controller having a regeneration processing unit executes control processing to actuate the fuel injector and to perform regeneration.

Abstract: A support member (40) is provided on a cylindrical member (23) of an upstream cylinder (22). A connector portion (34C) of a first temperature detector (34) for detecting the temperature of exhaust gas flowing into an oxidation catalyst (25), a connector portion (35C) of a second temperature detector (35) for detecting the temperature of the exhaust gas flowing into a particulate matter removing filter (31), and a sensor portion (39A) of a pressure detector (39) for detecting the front and rear pressures of the particulate matter removing filter (31) are arranged to be mounted on this support member (40). Accordingly, the support member (40) is capable of supporting the connector portions (34C, 35C) of the temperature detectors (34, 35) and the sensor portion (39A) of the pressure detector (39) in one location in a concentrated manner, so that harnesses on a controller side can be easily connected thereto.

Abstract: 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.

Abstract: 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 dosed state to increase a flow rate of the engine cooling medium to be guided to a heat exchanger of a heating apparatus.

Abstract: 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.

Abstract: 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 switch 22 is shifted to an ON-position, load control section 66 keeps at least one of the revolution speed N of an engine 1, the displacement volume q and discharge pressure P of a hydraulic pressure pump 11 at a corresponding first target value (N1, q1, or P1) or second target value (N2, q2, or P2) depending on a temperature of the cooling water in relation to a flame-out prevention temperature T1. A regeneration control section 67 starts 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 T0.

Abstract: 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 device 4 having a filter 6 to trap the PM, a regeneration control section 31 for compulsorily regenerating the filter, and a regeneration instruction device 23 for instructing the regeneration control section 31 to 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 device 12 notifies an operator that the time has come to start the movement of the working machine to the place of regeneration.

Abstract: An engine powered machine is provided with an economical exhaust gas purification system capable of avoiding overheating. The engine powered machine is provided with an exhaust gas purification system that injects a reducing agent into an exhaust pipe of an engine by a reducing agent feeder to detoxify nitrogen oxides in exhaust gases. A cooling fan, the driving or stopping of which is controlled by a controller, is arranged as a cooling device for a reducing agent tank in which the reducing agent to be injected by the reducing agent feeder is stored. When a detected temperature signal output from a reducing agent temperature detector has become higher than a cooling initiation temperature stored in a storage unit, the controller drives the cooling fan to initiate cooling of the reducing agent tank.

Abstract: [Problem] To provide a mounting structure for an NOx reduction system for a construction machine, said mounting structure being capable of relaxing restrictions on a space for the arrangement of the NOx reduction system.