Abstract:
This invention relates to a construction machine in which an operator can easily confirm that DEF level in a DEF tank has exceeded a predetermined level, when supplying DEF. With reference to  FIG. 1 , the construction machine comprises a DEF tank for storing DEF, a DEF level sensor for detecting DEF level in the DEF tank, warning means which warns to the operator and a controller which is connected to the DEF level sensor and the warning means. When DEF in the DEF tank exceeds a predetermined level which is detected by the DEF level sensor, the controller actuates the warning means. The warning means comprises at least one light e.g. a boom light or/and a horn.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a construction machine including a urea water tank that stores urea water serving as a reducing agent of nitrogen oxide. 
       BACKGROUND ART 
       [0002]    In vehicles such as construction vehicles, buses and trucks, a diesel engine is often used as a driving source. A lot of nitrogen oxide (NOx) and the like are included in exhaust gas of the diesel engine, and most of vehicles mounted with diesel engines are therefore subjected to emission control. Therefore, concerning the vehicles mounted with the diesel engines, it is requested to reduce a nitrogen oxide amount in the exhaust gas. 
         [0003]    As a technique for reducing the nitrogen oxide amount in the exhaust gas, a urea SCR (Selective Catalytic Reduction) system is known. The urea SCR system causes a reduction reaction of nitrogen oxide in exhaust gas and urea water to thereby reduce a nitrogen oxide amount in the exhaust gas. The urea water serving as a reducing agent is stored in a urea water tank mounted on a vehicle, sucked by a urea water suction pump, and ejected from ejecting means, which is connected to an exhaust passage of an engine, into the exhaust passage. 
         [0004]    Supply of the urea water to the urea water tank is performed using a urea water supply machine having a water supply stop function, a general-purpose container, or the like. When the water supply is performed using the urea water supply machine, the water supply is stopped by the water supply stop function of the urea water supply machine when a urea water amount in the urea water tank exceeds a predetermined amount. On the other hand, in a place where the urea water supply machine is not set such as a construction site, when the water supply is performed using the general-purpose container or the like, an operator needs to stop the water supply by himself or herself when the urea water amount in the urea water tank exceeds the predetermined amount. Therefore, on the outside of the urea water tank, in order to enable the operator to visually check the urea water amount in the urea water tank, a tubular gauge communicating with the inside of the urea water tank is sometimes disposed (see, for example, PTL 1). 
       SUMMARY OF INVENTION 
       [0005]    However, since a required amount of the urea water is small compared with fuel, usually, the urea water tank is formed smaller than a fuel tank. Therefore, it is sometimes difficult to visually recognize the gauge depending on a disposition place of the urea water tank in the vehicle. In this case, it is likely that the operator cannot confirm that the urea water amount in the urea water tank exceeds the predetermined amount and allows the urea water to overflow from the urea water tank. 
         [0006]    The present invention has been devised in view of the above-mentioned fact and a main technical problem of the present invention is to provide a construction machine with which, irrespective of a disposition place of an urea water tank, an operator can easily confirm that a urea water amount in the urea water tank exceeds a predetermined amount when the operator is supplying urea water to the urea water tank. 
         [0007]    According to the present invention, as a construction machine that solves the technical problem, there is provided a construction machine including: a urea water tank that stores urea water; detecting means for detecting a urea water amount in the urea water tank; warning means for issuing a warning to an operator who supplies the urea water to the urea water tank; and a controller connected to the detecting means and the warning means. The controller actuates the warning means when the detecting means detects that the urea water amount in the urea water tank exceeds a predetermined amount. 
         [0008]    Preferably, the warning means is constituted by light emitting means. The controller suitably lights the light emitting means when the detecting means detects that the urea water amount in the urea water tank exceeds the predetermined amount. The controller favorably flashes the light emitting means when the detecting means detects that the urea water amount in the urea water tank is increasing. Preferably, the warning means is constituted by warning sound means for emitting a warning sound. The controller suitably continuously sounds the warning sound means when the detecting means detects that the urea water amount in the urea water tank exceeds the predetermined amount. The controller favorably intermittently sounds the warning sound means when the detecting means detects that the urea water amount in the urea water tank is increasing. Preferably, the warning means is constituted by light emitting means and warning sound means for emitting a warning sound. The controller suitably flashes the light emitting means when the detecting means detects that the urea water amount in the urea water tank is increasing, and sounds the warning sound means when the detecting means detects that the urea water amount in the urea water tank exceeds the predetermined amount. The controller favorably intermittently sounds the warning sound means when the detecting means detects that the urea water amount in the urea water tank is increasing, and lights or flashes the light emitting means when the detecting means detects that the urea water amount in the urea water tank exceeds the predetermined amount. The controller preferably changes a flashing interval of the light emitting means according to the urea water amount in the urea water tank detected by the detecting means. The controller suitably changes a sounding interval of the warning sound means according to the urea water amount in the urea water tank detected by the detecting means. 
         [0009]    In the construction machine provided by the present invention, the controller actuates the warning means when the detecting means detects that the urea water amount in the urea water tank exceeds the predetermined amount. Therefore, according to the warning from the warning means, the operator can easily confirm that the urea water amount in the urea water tank exceeds the predetermined amount when the operator is supplying the urea water to the urea water tank. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0010]      FIG. 1  is a side view of a hydraulic excavator configured according to the present invention. 
           [0011]      FIG. 2  is a perspective view of an upper slewing body shown in  FIG. 1 . 
           [0012]      FIG. 3  is a perspective view of the inside of a cab shown in  FIG. 1  and  FIG. 2 . 
           [0013]      FIG. 4  is a diagram showing a configuration example of the hydraulic excavator shown in  FIG. 1 . 
           [0014]      FIG. 5  is an electric circuit diagram showing connection of a controller, a horn, and a horn switch. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    First and second embodiments of a construction machine configured according to the present invention are explained in detail below with reference to the accompanying drawings citing a hydraulic excavator, which is a representative construction machine, as an example. 
         [0016]    First, the first embodiment of the construction machine according to the present invention is explained. Referring to  FIG. 1 , the hydraulic excavator indicated by reference numeral  2  as a whole is roughly constituted by a lower traveling body  4  capable of self-traveling, an upper slewing body  6  mounted on the lower traveling body  4  so as to be able to slew, and a work arm apparatus  8  pivotably connected to the upper slewing body  6 . During digging work of earth and sand and the like, the work arm apparatus  8  is pivoted and the upper slewing body  6  is slewed with respect to the lower traveling body  4 , whereby the hydraulic excavator  2  can perform the digging work of the earth and sand and the like. 
         [0017]    The work arm apparatus  8  is roughly constituted by a boom  10  pivotably connected to the front side of the upper slewing body  6 , an arm  12  swingably connected to the distal end side of the boom  10 , a work tool  14  turnably connected to the distal end side of the arm  12 , a pair of boom cylinders  16  (only the left side is shown) that pivots the boom  10 , an arm cylinder  18  that swings the arm  12 , and a work tool cylinder  20  that turns the work tool  14 . A boom work lamp  22  that illuminates an area ahead of the hydraulic excavator  2  is disposed in a side surface center portion of the boom  10 . 
         [0018]    The hydraulic excavator  2  is explained with reference to  FIG. 2  together with  FIG. 1 . The upper slewing body  6  includes a slewing frame  24  that forms a framework structure. In the slewing frame  24 , a diesel engine  26  forming a driving source, a storage-battery housing chamber  27 , a fuel tank  28  that stores fuel, a tool box  30  in which apparatuses necessary for actuation of the hydraulic excavator  2 , or tools and the like used for maintenance are housed, a urea water tank  32  that stores urea water, a cab  34  on which a driver rides, a controller  36  (see  FIG. 4 ) and the like are disposed. 
         [0019]    In the storage-battery housing chamber  27 , a storage battery  27   a,  a shutoff switch (not shown in the figure), an actuation indicator lamp  27   b  (see  FIG. 4 ), and the like are disposed. The shutoff switch is a switch for shutting off power supply when inspection or the like of the hydraulic excavator  2  is performed. When the shutoff switch is off, power supply from the storage battery  27   a  to the apparatuses is shut off. On the other hand, when the shutoff switch is on, the power supply from the storage battery  27   a  to the apparatuses is allowed. However, even when the shutoff switch is off and when a key switch  49  explained below is off, in a predetermined case, some apparatuses receive the supply of electric power from the storage battery  27   a  and operate. Therefore, the working of such apparatuses is indicated by lighting of the actuation indicator lamp  27   b.    
         [0020]    The fuel tank  28  is formed in a rectangular parallelepiped shape as a whole from an appropriate steel material and disposed on the right front side of the slewing frame  24 . A fuel filler port  28   a  is disposed on the upper surface of the fuel tank  28 . A step  28   b  serving as a foot rest when the operator steps up to the upper slewing body  6  for inspection and maintenance is joined to a height-direction middle portion of the front surface of the fuel tank  28 . Fuel-amount detecting means  28   c  (see  FIG. 4 ) for detecting a fuel amount is disposed in the fuel tank  28 . The fuel-amount detecting means  28   c  is constituted by a level sensor or the like. 
         [0021]    The tool box  30  is formed in a rectangular parallelepiped shape as a whole from an appropriate steel material and smaller than the fuel tank  28  in a dimension in the up-down direction and disposed in front of the fuel tank  28 . The upper surface of the tool box  30  is in a lower position than the step  28   b  of the fuel tank  28  and formed as a lid section  30   a  serving as a foot rest of the operator like the step  28   b  of the fuel tank  28  and capable of opening and closing via a hinge. An opening  30   b  is formed on the front surface of the tool box  30 . A slewing-body work lamp  38  that illuminates the area ahead of the hydraulic excavator  2  is housed in the tool box  30  to face the opening  30   b.    
         [0022]    The urea water tank  32  is formed in a rectangular parallelepiped shape as a whole from an appropriate resin material or a steel material having relatively high corrosion resistance, for example, stainless steel and smaller than the fuel tank  28  and the tool box  30  and housed in the tool box  30 . The upper surface of the urea water tank  32  includes a horizontal surface extending substantially horizontally and an inclining surface inclining downward and extending forward from the horizontal surface. A water supply port  32   a  is disposed on the inclining surface. Urea-water-amount detecting means  32   b  (see  FIG. 4 ) for detecting a urea water amount is disposed in the urea water tank  32 . The urea-water-amount detecting means  32   b  is constituted by a level sensor or the like. The urea water tank  32  is connected to a urea water pump  33  (see  FIG. 4 ). The urea water in the urea water tank  32  is sucked by the urea water pump  33  and ejected from ejecting means (not shown in the figure), which is connected to an exhaust passage of the engine  26 , into the exhaust passage. Note that, even when the shutoff switch is off and when the key switch  49  explained below is off, the urea water pump  33  sometimes receive power supply from the storage battery  27   a  and operates. 
         [0023]    The cab  34  is formed in a frame structure from a plurality of columns  40  formed from a steel pipe and a plurality of beams  42  formed from a steel pipe and coupling the plurality of columns  40 , covered with a window  44  and the like on a peripheral side surface, and disposed on the left front side of the slewing frame  24 . A pair of left and right cab work lamps  46  that illuminates the area ahead of the hydraulic excavator  2  is disposed in a front surface upper portion of the cab  34 . An operation indicator lamp  47  indicating that the hydraulic excavator  2  is operating is disposed in an upper surface rear portion of the cab  34 . Note that the front-back direction and the left-right direction used in the explanation of this specification are the front-back direction and the left-right direction viewed from the driver riding on the cab  34  shown in  FIG. 1  and  FIG. 2 . 
         [0024]    The cab  34  is explained with reference to  FIG. 3 . In the cab  34 , a seat  48  on which the driver is seated, a key switch  49  that performs operation and stop of the engine  26  and allows and shuts off the power supply from the storage battery  27   a  to the apparatuses, a plurality of operation devices  50  that output signals for actuating a hydraulic actuator such as the boom cylinders  16 , a display  52  that displays machine information and the like necessary for the driver, an indoor lamp  53  (see  FIG. 4 ) that illuminates the inside of the cab  34 , a switch panel  54  on which at least one switch is disposed, and the like are disposed. The key switch  49  can be configured form, for example, a well-known mechanical switch. When the key switch  49  is off, the engine  26  stops and the power supply from the storage battery  27   a  to the apparatuses is shut off. When the key switch  49  is turned from OFF to ON, the power supply from the storage battery  27   a  to the apparatuses is allowed. When the key switch  49  is further turned from ON to start, the engine  26  is actuated. A horn switch  50   a  that outputs a signal for sounding a horn  56  (see  FIG. 4 ) is disposed on the upper surface of one of the operation devices  50 , that is, in this embodiment, the operation device  50  located on the left side of the seat  48 . The horn  56  emits a warning sound to the periphery of the hydraulic excavator  2 . The horn  56  is used to, for example, call attention of other operators present around the hydraulic excavator  2 , for example, when the operator starts the engine  26 . When the operation devices  50 , for example, a pair of operation devices  50  located in front of the seat  48  is operated, a signal for causing the hydraulic excavator  2  to travel by the lower traveling body  4  is output and a signal for sounding a traveling alarm  58  (see  FIG. 4 ) is output. The traveling alarm  58  emits a warning sound to the periphery of the hydraulic excavator  2 . The traveling alarm  58  is used to notify the other operators present around the hydraulic excavator  2  that the hydraulic excavator  2  is traveling. 
         [0025]    A screen  52   a  is disposed in the display  52 , in a position where the screen  52   a  can be visually recognized from the driver seated on the seat  48 . Machine information images and the like of a fuel amount in the fuel tank  28 , a urea water amount in the urea water tank  32 , and the like are displayed on the screen  52   a.  A plurality of input means  52   b  are disposed below the screen  52   a  in the display  52 . An image displayed on the screen  52   a  changes according to an input from the input means  52   b  and changes according to a signal or the like from the controller  36  as well. Further, in the display  52 , a buzzer  52   c  (see  FIG. 4 ) that emits a warning sound is incorporated. The buzzer  52   c  is used to notify the driver that, for example, various apparatuses are in abnormal states and replacement time of a predetermined component has passed. On the switch panel  54 , a work lamp switch  54   a  for outputting signals for lighting or extinguishing the boom work lamp  22 , the slewing-body work lamp  38 , and the cab work lamps  46 , an indoor lamp switch  54   b  that outputs a signal for lighting or extinguishing the indoor lamp  53 , and the like are disposed. Note that the input means  52   b,  the work lamp switch  54   a,  and the indoor lamp switch  54   b  are constituted by a switch of a push button type in this embodiment. However, the input means  52   b,  the work lamp switch  54   a,  and the indoor lamp switch  54   b  may be a dial type, a seesaw type, a touch panel type, or a combination of these types. The buzzer  52   c  may be disposed in an appropriate place in the cab  34  rather than in the display  52 . 
         [0026]    The hydraulic excavator  2  is explained with reference to  FIG. 4 . The controller  36  is an electronic control device provided as an LSI device or an integrated electronic device in which a microprocessor, a ROM, a RAM, and the like, which are publicly known, are integrated. The controller  36  is disposed in an appropriate position of the upper slewing body  6 . The controller  36  is electrically connected to the key switch  49 , the operation devices  50 , the display  52 , and the switch panel  54  disposed in the cab  34  and is electrically connected to the fuel-amount detecting means  28   c,  the urea-water-amount detecting means  32   b,  the urea water pump  33 , the actuation indicator lamp  27   b,  the operation indicator lamp  47 , the boom work lamp  22 , the slewing-body work lamp  38 , the cab work lamps  46 , the indoor lamp  53 , the horn  56 , the traveling alarm  58 , and the like. 
         [0027]    When the key switch  49  is operated to actuate the engine  26 , the controller  36  lights the operation indicator lamp  47 . When detecting that the urea water pump  33  is working, the controller  36  lights the actuation indicator lamp  27   b.  When signals for lighting or extinguishing the work lamps  22 ,  38 , and  46  are output from the work lamp switch  54   a,  the controller  36  lights or extinguishes the work lamps  22 ,  38 , and  46 . When a signal for lighting or extinguishing the indoor lamp  53  is output from the indoor lamp switch  54   b,  the controller  36  lights or extinguishes the indoor lamp  53 . When a signal for sounding the horn  56  is output from the horn switch  50   a  of the operation device  50 , the controller  36  sounds the horn  56 . When a signal for causing the hydraulic excavator  2  to travel by the lower traveling body  4  is output from the operation device  50 , the controller  36  sounds the traveling alarm  58 . When detecting abnormal states or the like of the apparatuses, the controller  36  sounds the buzzer  52   c.  Further, the controller  36  outputs a fuel amount and a urea water amount detected by the fuel-amount detecting means  28   c  and the urea-water-amount detecting means  32   b  to the display  52 . 
         [0028]    In the hydraulic excavator  2  configured as explained above, when the urea water is supplied to the urea water tank  32  and the urea-water-amount detecting means  32   b  detects that the urea water amount in the urea water tank  32  is increasing, the controller  36  flashes any one or a plurality of work lamps among the boom work lamp  22 , the slewing-body work lamp  38 , and the cab work lamps  46 . A flashing interval of the work lamps is changed by the controller  36  according to the urea water amount in the urea water tank  32  to, for example, 1 Hz when the urea-water-amount detecting means  32   b  detects that the urea water amount in the urea water tank  32  exceeds 70% of the capacity of the urea water tank  32  and 2 Hz when it is detected that the urea water amount exceeds 80%. Consequently, the operator can recognize an approximate urea water amount in the urea water tank  32  when the operator is supplying the urea water to the urea water tank  32 . 
         [0029]    After flashing the work lamps, when the urea-water-amount detecting means  32   b  detects that the urea water amount in the urea water tank  32  exceeds a predetermined amount, for example, 90% of the capacity of the urea water tank  32 , the controller  36  lights any one or a plurality of work lamps among the boom work lamp  22 , the slewing-body work lamp  38 , and the cab work lamps  46  or continuously or intermittently sound the horn  56 . When any one of the work lamps is flashed, the work lamps lit by the controller  36  are the flashed lamp or/and the other work lamps. On the other hand, when the plurality of work lamps are flashed, the work lamps lit by the controller  36  are the flashed plurality of work lamps or/and the other work lamps. 
         [0030]    The work lamps are lit or the horn  56  is sounded in this way, whereby the operator can easily confirm that the urea water amount in the urea water tank  32  exceeds the predetermined amount when the operator is supplying the urea water to the urea water tank  32 . As a result, the operator does not allow the urea water to overflow from the urea water tank  32 . When the urea-water-amount detecting means  32   b  detects that the urea water amount in the urea water tank  32  does not fluctuate for a predetermined time after exceeding the predetermined amount, the controller  36  extinguishes the work lamps. In the case where the horn  56  has been sounded, the controller  36  stops the sounding of the horn  56 . 
         [0031]    A second embodiment of the construction machine according to the present invention is explained. Note that, in the second embodiment, components same as the components in the first embodiment explained above are denoted by the same reference numerals and signs and explanation of the components is omitted. 
         [0032]    When urea water is supplied to the urea water tank  32  and the urea-water-amount detecting means  32   b  detects that the urea water amount in the urea water tank  32  is increasing, the controller  36  intermittently sounds the horn  56 . A sounding interval of the horn  56  is changed by the controller  36  according to the urea water amount in the urea water tank  32  to, for example, 1 Hz when the urea-water-amount detecting means  32   b  detects that the urea water amount in the urea water tank  32  exceeds 70% of the capacity of the urea water tank  32  and 2 Hz when it is detected that the urea water amount exceeds 80%. Consequently, an operator can recognize an approximate urea water amount in the urea water tank  32  when the operator is supplying the urea water to the urea water tank  32 . 
         [0033]    After intermittently sounding the horn  56 , when the urea-water-amount detecting means  32   b  detects that the urea water amount in the urea water tank  32  exceeds a predetermined amount, for example, 90% of the capacity of the urea water tank  32 , the controller  36  continuously sounds the horn  56  or lights or flashes any one or a plurality of work lamps among the boom work lamp  22 , the slewing-body work lamp  38 , and the cab work lamps  46 . Consequently, the operator can easily confirm that the urea water amount in the urea water tank  32  exceeds the predetermined amount when the operator is supplying the urea water to the urea water tank  32 . As a result, the operator does not allow the urea water to overflow from the urea water tank  32 . When the urea-water-amount detecting means  32   b  detects that the urea water amount in the urea water tank  32  does not fluctuate for a predetermined time after exceeding the predetermined amount, the controller  36  stops the sounding of the horn  56  and, when the work lamps are lit or flashed, extinguishes the work lamps. 
         [0034]    In the first and second embodiments, the warning means for issuing a warning to the operator, who supplies the urea water to the urea water tank  32 , is constituted by the light emitting means such as the boom work lamp  22  that illuminates the periphery of the hydraulic excavator  2  or/and the horn  56  used, for example, when calling attention of the other operators present around the hydraulic excavator  2 , for example, when the operator starts the engine  26 . Therefore, exclusive warning means for issuing a warning is unnecessary. This is advantageous in terms of manufacturing costs and component management. 
         [0035]    Note that the first and second embodiments explained above are illustrations of the present invention. The present invention is not limited to the embodiments. Various changes of the embodiments are possible. For example, the light emitting means functioning as the warning means is explained using the boom work lamp  22 , the slewing-body work lamp  38 , and the cab work lamps  46  as an example. However, the light emitting means may be any light emitting means as long as the operator supplying the urea water to the urea water tank  32  can recognize that the light emitting means is lit and flashing. The light emitting means may be, for example, the actuation indicator lamp  27   b,  the operation indicator lamp  47 , or the indoor lamp  53  according to a disposition place of the urea water tank  32 . The warning sound means functioning as the warning means is explained using the horn  56  as an example. However, the warning sound means any warning sound means as long as the operator supplying the urea water to the urea water tank  32  can recognize that the warning sound means is sounding. The warning sound means may be the buzzer  52   c  or the traveling alarm  58  according to a disposition place of the urea water tank  32 . When the actuation indicator lamp  27   b,  the operation indicator lamp  47 , or the indoor lamp  53  or the buzzer  52   c  or the traveling alarm  58  is used as the warning means, exclusive warning means is unnecessary as in the case where the work lamps or the horn is used as the warning means. This is advantageous in terms of manufacturing costs and component management. Light emitting means and warning sound means other than those explained above may be used as the warning means. Exclusive light emitting means or warning sound means for configuring the warning means may be disposed. 
         [0036]    Concerning the start of the flashing of the light emitting means or the start of the intermittent sounding of the warning sound means, in the embodiments, the configuration is explained in which, when the urea-water-amount detecting means  32   b  detects that the urea water amount in the urea water tank  32  is increasing, the controller  36  starts the flashing of the light emitting means or starts the intermittent sounding of the warning sound means. However, a configuration may be adopted in which, when the operator supplies the urea water, the operator may manually operate, for example, the input means  52   b  of the display  52  or the switch disposed on the switch panel  54  to thereby start the flashing of the light emitting means or the intermittent sounding of the warning sound means. A configuration can be adopted in which, after the flashing of the light emitting means or the intermittent sounding of the warning sound means is started, the controller  36  changes the flashing interval of the light emitting means or the sounding interval of the warning sound means according to the urea water amount in the urea water tank  32  detected by the urea-water-amount detecting means  32   b.    
         [0037]    A configuration may be adopted in which, only when the urea-water-amount detecting means  32   b  detects that the urea water amount in the urea water tank  32  exceeds the predetermined amount, the controller  36  lights or flashes the light emitting means or intermittently or continuously sounds the warning sound means. The controller may consist of one controller or a plurality of controllers may be disposed in separate places and electrically connected to one another. The configuration is explained in which, when the signals for lighting or extinguishing the light emitting means such as the work lamps or for sounding the warning sound means such as the horn are output to the controller from the switches, the controller lights or extinguishes the light emitting means such as the work lamps, or sounds the warning sound means such as the horn. However, for example, as shown in  FIG. 5 , the switches does not have to be connected to the apparatuses via the controller as long as the horn  56  is connected to the controller  36  and the horn switch  50   a  respectively via relays  60  and  62 .