JP2017166199A - Asphalt finisher - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an asphalt finisher which can purify exhaust gas.SOLUTION: An asphalt finisher 100 includes a tractor 1, a hopper 2 provided in a front side of the tractor 1, a conveyor 10 which conveys a pavement material in the hopper 2 to a rear side of the tractor 1, a screw 11 which spreads and lays, in a vehicle width direction, the pavement material conveyed by the conveyor 10 and scattered on a road, a screed 3 which lays and flattens, in a rear side of the screw 11, the pavement material spread and laid by the screw 11, an engine 6 mounted in the tractor 1, a hydraulic pump driven by an engine 6, an exhaust gas post-treatment device 7 which purifies exhaust gas from the engine 6, and a controller 30 which reduces the output of the engine 6 and the output horse power of the hydraulic pump when an abnormality of the exhaust gas post-treatment device 7 is detected.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an asphalt finisher equipped with an exhaust gas aftertreatment device.

  A self-propelled asphalt finisher driven by an engine is known (see Patent Document 1). The engine mounted on this asphalt finisher exhausts exhaust gas containing nitrogen oxides.

JP2015-1335026

  However, Patent Document 1 does not mention an apparatus for purifying exhaust gas and a process when an abnormality is detected in such an apparatus. In view of the above, it is desired to provide an asphalt finisher that can operate properly even when an abnormality occurs in the exhaust gas aftertreatment device.

  An asphalt finisher according to an embodiment of the present invention includes a tractor, a hopper installed on the front side of the tractor, a conveyor that conveys the paving material in the hopper to the rear side of the tractor, and a road surface that is conveyed by the conveyor. A screw that spreads pavement material spread on the vehicle in the vehicle width direction, a screed that spreads the pavement material spread by the screw on the back side of the screw, an engine mounted on the tractor, and the engine A hydraulic pump driven by the engine, an exhaust gas aftertreatment device that purifies the exhaust gas of the engine, and an output of the hydraulic pump that reduces the output of the engine and detects an abnormality in the exhaust gas aftertreatment device And a control device for reducing horsepower.

  The above-described means provides an asphalt finisher that can operate properly even when an abnormality occurs in the exhaust gas aftertreatment device.

It is a figure of the asphalt finisher which concerns on the Example of this invention. It is a hydraulic circuit diagram which shows the structural example of the hydraulic system mounted in the asphalt finisher of FIG. It is a figure which shows the structural example of the exhaust-gas aftertreatment system mounted in the asphalt finisher of FIG. It is a figure which shows the structural example of an output image. It is a figure which shows another structural example of an output image. It is a flowchart which shows the flow of the process at the time of abnormality detection. It is a flowchart which shows the flow of an escape process. It is a flowchart which shows the flow of a process at the time of residual amount abnormality detection. It is a flowchart which shows the flow of a horsepower reduction process. It is a figure which shows the relationship between the margin of an engine torque, and the amount of restrictions on the machine side.

  FIG. 1 is a diagram of an asphalt finisher 100 that is an example of a road machine according to an embodiment of the present invention. Specifically, FIG. 1A is a left side view, and FIG. 1B is a top view.

  The asphalt finisher 100 mainly includes a tractor 1, a hopper 2, and a screed 3.

  The tractor 1 is a mechanism for running the asphalt finisher 100. In this embodiment, the tractor 1 moves the asphalt finisher 100 by rotating the front wheels 4 and the rear wheels 5 using a traveling hydraulic motor. The traveling hydraulic motor rotates upon receiving hydraulic oil supplied from a hydraulic pump driven by the engine 6. The tractor 1 is equipped with an engine 6, an exhaust gas aftertreatment device 7, a fuel tank 8, a urea water tank 9, a controller 30, a monitor 77, and the like.

  The engine 6 and the exhaust gas aftertreatment device 7 are installed in the engine room. The engine chamber is formed on the −X side (rear side) of the hopper 2. In the present embodiment, in the engine room, the engine 6 is disposed on the −Y side (left side), and the exhaust gas aftertreatment device 7 is disposed adjacent to the + Y side (right side) of the engine 6.

  The upper surface of the engine chamber is partially covered with an engine hood 1a indicated by hatching, and the side surface is covered with an exterior cover 1b. The engine 6 and the exhaust gas aftertreatment device 7 are disposed in the engine hood 1a. The engine hood 1a is configured to be openable and closable, and a ventilation hole is formed on the surface thereof. The exterior cover 1b is configured not to be openable or closable, and has a vent hole formed on the surface thereof. In the present embodiment, a part of the engine hood 1a is made of punching metal, and another part has a ventilation louver. The exterior cover 1b has a ventilation louver.

  The fuel tank 8 and the urea water tank 9 are installed in the tank chamber. The tank chamber is formed on the −X side (rear side) of the hopper 2 and on the −Z side (lower side) of the engine chamber. In this embodiment, in the tank chamber, the fuel tank 8 and the urea water tank 9 are arranged on the −Y side (left side), and the urea water tank 9 is arranged adjacent to the −X side (rear side) of the fuel tank 8. The Therefore, the urea water tank 9 is disposed between the rear wheel 5 and the fuel tank 8 in a top view.

  The hopper 2 is a mechanism for receiving a paving material. In this embodiment, the hopper cylinder 2a is configured to be opened and closed in the Y-axis direction (vehicle width direction). The asphalt finisher 100 normally receives the pavement material (for example, asphalt mixture) from the loading platform of the dump truck as the pavement material transport vehicle with the hopper 2 fully opened. The paving material received in the hopper 2 is fed to the screed 3 using the conveyor 10 and the screw 11.

  The conveyor 10 conveys the paving material in the hopper 2 to the −X side (rear side) of the tractor 1. The screw 11 spreads the pavement material conveyed by the conveyor 10 and wound on the road surface in the Y-axis direction (vehicle width direction).

  The screed 3 is a mechanism for spreading and leveling the paving material. In this embodiment, the screed 3 is a floating screed pulled by the tractor 1 and is connected to the tractor 1 via the leveling arm 3a.

  The controller 30 is a control device that controls the asphalt finisher 100. In this embodiment, the controller 30 is composed of an arithmetic processing unit including a CPU and an internal memory. Various functions of the controller 30 are realized by the CPU executing a program stored in the internal memory.

  Next, the hydraulic system mounted on the asphalt finisher 100 of FIG. 1 will be described with reference to FIG. FIG. 2 is a hydraulic circuit diagram showing a configuration example of a hydraulic system mounted on the asphalt finisher 100 of FIG.

  The hydraulic system mainly includes a hydraulic pressure source 14, a rear wheel drive unit F1, and a conveyor / screw drive unit F2.

  The hydraulic pressure source 14 is a functional element that supplies hydraulic oil that operates various hydraulic drive units including the rear wheel drive unit F1 and the conveyor / screw drive unit F2. In the present embodiment, the hydraulic power source 14 mainly includes the engine 6, a rear wheel traveling pump 14R, a charge pump 14C, and a conveyor / screw pump 14S.

  The engine 6 is a drive source that drives the rear wheel pump 14R, the charge pump 14C, and the conveyor screw pump 14S.

  The rear wheel traveling pump 14R is a variable displacement hydraulic pump that supplies driving hydraulic oil to the rear wheel driving unit F1. In this embodiment, the rear wheel traveling pump 14R is a swash plate type variable displacement bidirectional hydraulic pump used in a closed circuit (HST), and its discharge amount is controlled by the pump regulator 15. Strictly speaking, the discharge amount is a discharge amount per one rotation of the pump, and is also referred to as a displacement volume. The rear wheel traveling pump 14R may be a fixed displacement hydraulic pump.

  The pump regulator 15 is a device that controls the discharge amount of the rear wheel traveling pump 14R. In this embodiment, the pump regulator 15 adjusts the discharge amount of the rear wheel traveling pump 14 </ b> R according to the pump command current from the controller 30. For example, the larger the current value of the pump command current, the larger the discharge amount of the rear wheel traveling pump 14R.

  The charge pump 14C is a fixed displacement hydraulic pump that supplies control oil to the rear wheel drive unit F1.

  The conveyor / screw pump 14S is a variable displacement hydraulic pump that supplies hydraulic oil to the conveyor / screw driving unit F2. In this embodiment, the conveyor screw pump 14S is a swash plate type variable displacement hydraulic pump. In this embodiment, the discharge amount of the conveyor screw pump 14S is controlled by the pump regulator 15A. The pump regulator 15 </ b> A adjusts the discharge amount of the conveyor screw pump 14 </ b> S according to the pump command current from the controller 30. For example, the larger the current value of the pump command current, the larger the discharge amount of the conveyor screw pump 14S. The conveyor screw pump 14S may be a fixed displacement hydraulic pump.

  The rear wheel drive unit F1 is a functional element that drives the rear wheels 5L and 5R. In the present embodiment, the rear wheel drive unit F1 includes a left rear wheel traveling motor 20L, a right rear wheel traveling motor 20R, check valves 20La and 20Ra, relief valves 20Lb and 20Rb, reduction ratio control devices 21L and 21R, and a brake. Control devices 22L and 22R are included.

  The left rear wheel travel motor 20L is a hydraulic motor that drives the left rear wheel 5L. The right rear wheel traveling motor 20R is a hydraulic motor that drives the right rear wheel 5R. In this embodiment, the left rear wheel traveling motor 20L and the right rear wheel traveling motor 20R are variable displacement hydraulic motors, and form a closed circuit (HST) together with the rear wheel traveling pump 14R. The left rear wheel traveling motor 20L and the right rear wheel traveling motor 20R may be fixed displacement hydraulic motors.

  The check valve 20La determines the pressure of the hydraulic oil in the pipe C1 that connects the first port of the rear wheel traveling pump 14R and the second ports of the left rear wheel traveling motor 20L and the right rear wheel traveling motor 20R. Maintain above predetermined pressure. Specifically, the check valve 20La causes the hydraulic oil discharged from the charge pump 14C to flow into the pipe line C1 when the pressure of the hydraulic oil in the pipe line C1 falls below the discharge pressure of the charge pump 14C. The numbers in parentheses in the figure represent port numbers. Similarly, the check valve 20Ra is a hydraulic oil in the pipe line C2 that connects the second port of the rear wheel traveling pump 14R and the first ports of the left rear wheel traveling motor 20L and the right rear wheel traveling motor 20R. The pressure is maintained at a predetermined pressure or higher. Specifically, the check valve 20Ra causes the hydraulic oil discharged from the charge pump 14C to flow into the pipe C2 when the pressure of the hydraulic oil in the pipe C2 falls below the discharge pressure of the charge pump 14C.

  The relief valve 20Lb maintains the pressure of the hydraulic oil in the pipe line C1 below a predetermined relief pressure. Specifically, the relief valve 20Lb causes the hydraulic oil in the pipe C1 to flow out of the closed circuit when the pressure of the hydraulic oil in the pipe C1 exceeds the relief pressure. Similarly, the relief valve 20Rb maintains the pressure of the hydraulic oil in the pipe line C2 below a predetermined relief pressure. Specifically, the relief valve 20Rb causes the hydraulic oil in the pipe C2 to flow out of the closed circuit when the pressure of the hydraulic oil in the pipe C2 exceeds the relief pressure.

  The reduction ratio control device 21L is a device that controls the reduction ratio of the reduction gear connected to the left rear wheel travel motor 20L. In the present embodiment, the reduction ratio control device 21L determines the reduction ratio of the reduction gear connected to the left rear wheel travel motor 20L using the hydraulic oil discharged from the charge pump 14C in response to a control command from the controller 30. adjust. The same applies to the reduction ratio control device 21R that adjusts the reduction ratio of the reduction gear connected to the right rear wheel travel motor 20R.

  The brake control device 22L is a device that controls the braking force of the left rear wheel brake that brakes the left rear wheel 5L of the asphalt finisher 100. In the present embodiment, the brake control device 22L adjusts the braking force of the left rear wheel brake using hydraulic oil discharged from the charge pump 14C in response to a control command from the controller 30. The same applies to the brake control device 22R that adjusts the braking force of the right rear wheel brake.

  The conveyor / screw drive unit F2 is a functional element that drives the conveyor and the screw. In the present embodiment, the conveyor screw driving unit F2 mainly includes a control valve 41, a left screw motor 42SL, a right screw motor 42SR, a left conveyor motor 42CL, a right conveyor motor 42CR, and a generator motor 42G.

  The left screw motor 42SL and the right screw motor 42SR rotate the screw 11. The left conveyor motor 42CL and the right conveyor motor 42CR rotate the conveyor 10. The generator motor 42G drives the generator 43 to rotate. The generator 43 generates electric power to be supplied to a heater or the like that heats a heating required portion of the asphalt finisher 100.

  Each of the left screw motor 42SL, the right screw motor 42SR, the left conveyor motor 42CL, the right conveyor motor 42CR, and the generator motor 42G is a fixed displacement hydraulic motor that forms an open circuit. Note that these hydraulic motors may be variable displacement hydraulic motors.

  The control valve 41 includes a conveyor control valve, a screw control valve, and a generator control valve. The conveyor control valve is switched in response to a control command from the controller 30, and causes the hydraulic oil discharged from the conveyor screw pump 14S to flow into at least one suction port of the left conveyor motor 42CL and the right conveyor motor 42CR, and The hydraulic oil flowing out from at least one discharge port of the left conveyor motor 42CL and the right conveyor motor 42CR is discharged to the hydraulic oil tank T. The screw control valve is switched in accordance with a control command from the controller 30, and causes the hydraulic oil discharged from the conveyor screw pump 14S to flow into at least one suction port of the left screw motor 42SL and the right screw motor 42SR, and The hydraulic oil flowing out from at least one discharge port of the left screw motor 42SL and the right screw motor 42SR is discharged to the hydraulic oil tank T. Similarly, the generator control valve is switched in response to a control command from the controller 30 to cause the hydraulic oil discharged from the conveyor screw pump 14S to flow into the suction port of the generator motor 42G, and for the generator. The hydraulic oil flowing out from the discharge port of the motor 42G is discharged to the hydraulic oil tank T. Further, the conveyor control valve, the screw control valve, and the generator control valve all change the opening according to a command from the controller 30 to adjust the flow rate of the hydraulic oil toward the corresponding motor.

  FIG. 3 is a diagram showing a configuration example of the exhaust gas aftertreatment system 150 mounted on the asphalt finisher 100 of FIG. The exhaust gas aftertreatment system 150 purifies the exhaust gas discharged from the engine 6 which is a diesel engine.

  The exhaust gas post-processing device 7 is a device that purifies exhaust gas of the engine 6 in stages, and includes a first processing unit 7a and a second processing unit 7b. The 1st process part 7a is a diesel particulate filter which collects the particulate matter in exhaust gas, for example. The second processing unit 7b is, for example, a selective catalytic reduction (SCR) system that reduces and removes NOx in exhaust gas.

  The SCR system as the second processing unit 7b receives the supply of the reducing agent and continuously reduces and removes NOx in the exhaust gas. In this embodiment, urea water (urea aqueous solution) is used as a reducing agent for ease of handling.

  The air introduced into the intake pipe 6b through the air filter 6a passes through the turbocharger 61 and the intercooler 65 and is supplied to the engine 6. The exhaust gas from the engine 6 passes through the turbocharger 61, reaches the exhaust pipe 6c downstream thereof, is purified by the exhaust gas aftertreatment device 7, and is discharged into the atmosphere.

  A first processing unit 7 a and a second processing unit 7 b of the exhaust gas aftertreatment device 7 are connected in series to the exhaust pipe 6 c through a connection unit 63. The connecting portion 63 is provided with a urea water injection device 68 for supplying urea water to the SCR system. The urea water injection device 68 is connected to the urea water tank 9 via a urea water hose 69.

  A supply module SM is provided in the middle of the urea water hose 69. The supply module SM includes a urea water supply pump 70 and a filter 71. In the present embodiment, the supply module SM is configured such that a filter 71 is disposed between the urea water tank 9 and the urea water supply pump 70.

  The urea water stored in the urea water tank 9 is supplied to the urea water injection device 68 by the urea water supply pump 70, and the upstream position of the second processing unit 7b (SCR system) in the exhaust pipe 6c from the urea water injection device 68. It is injected toward

  The urea water injected from the urea water injection device 68 is supplied to the SCR system. The supplied urea water is hydrolyzed at the SCR system to produce ammonia. This ammonia reduces NOx contained in the exhaust gas. In this way, exhaust gas purification is performed.

  The first NOx sensor 72 and the second NOx sensor 73 are sensors that detect the NOx concentration in the exhaust gas. In the present embodiment, the first NOx sensor 72 is disposed on the upstream side of the urea water injection device 68, and the second NOx sensor 73 is disposed on the downstream side of the SCR system.

  The urea water remaining amount sensor 74 is a sensor that detects the urea water remaining amount in the urea water tank 9. The urea water concentration sensor 74 </ b> A is a sensor that detects the concentration of urea water in the urea water tank 9. In this embodiment, the urea water remaining amount sensor 74 and the urea water concentration sensor 74 </ b> A are disposed in the upper part of the urea water tank 9.

  The first NOx sensor 72, the second NOx sensor 73, the urea water remaining amount sensor 74, the urea water concentration sensor 74A, the urea water injection device 68, and the urea water supply pump 70 are connected to the exhaust gas controller 75. The exhaust gas controller 75 controls the urea water injection device 68 and the urea water supply pump 70 based on the NOx concentrations detected by the first NOx sensor 72 and the second NOx sensor 73, respectively, and an appropriate amount of urea water is injected. Like that.

  Further, the exhaust gas controller 75 calculates the ratio of the urea water remaining amount to the total volume of the urea water tank 9 based on the urea water remaining amount output from the urea water remaining amount sensor 74. In this embodiment, the ratio of the remaining amount of urea water to the total volume of the urea water tank 9 is the urea water remaining ratio. For example, the urea water remaining ratio 50 [%] indicates that the urea water half of the capacity of the urea water tank 9 remains in the urea water tank 9.

  The exhaust gas controller 75 is connected to an engine control module (hereinafter referred to as “ECM”) 60 via a CAN or the like. The ECM 60 is a device that controls the engine 6. The ECM 60 is connected to the controller 30 via a CAN or the like, and the controller 30 is connected to a monitor 77 (display device) via the CAN or the like. The monitor 77 can display warnings, operating conditions, and the like. The monitor 77 also monitors CAN communication between the controller 30 and the ECM 60 and CAN communication between the ECM 60 and the exhaust gas controller 75.

  Each of the ECM 60 and the exhaust gas controller 75 is an arithmetic device including a CPU, a RAM, a ROM, an input / output port, a storage device and the like. The controller 30 can use various types of information regarding the exhaust gas aftertreatment system 150 that the exhaust gas controller 75 has.

  The exhaust gas aftertreatment system 150 has a heat supply mechanism for supplying heat to the urea water tank 9 and the urea water hose 69. The heat supply mechanism is, for example, a mechanism for preventing freezing of urea water in a cold region or dissolving frozen urea water. In this embodiment, engine coolant (for example, long life coolant) of the engine 6 that passes through the coolant hose 80 is used.

  Specifically, the engine coolant immediately after cooling the engine 6 reaches the second portion 82 through the first portion 81 of the coolant hose 80 while maintaining a relatively high temperature. The second portion 82 is a part of the cooling water hose 80 that contacts the outer surface of the urea water tank 9. When the engine cooling water having a temperature higher than that of the urea water flows through the second portion 82, heat is supplied to the urea water tank 9 and the urea water in the urea water tank 9.

  Thereafter, the engine coolant reaches the third portion 83 and the supply module SM. The third portion 83 is a part of the cooling water hose 80 that is in close contact with the urea water hose 69. When the engine cooling water having a temperature higher than that of the urea water flows through the third portion 83 of the cooling water hose 80 along the urea water hose 69, the engine cooling water supplies heat to the urea water hose 69 and the urea water therein. Further, the engine cooling water having a temperature higher than that of the urea water flows into the supply module SM (including the urea water supply pump 70 and the filter 71) and the urea water in the inside thereof when flowing through the flow path formed in the supply module SM. Supply heat.

  Thereafter, the engine coolant that has reached a relatively low temperature after finishing the supply of heat in the second portion 82 and the third portion 83 reaches the heat exchanger unit 13 through the fourth portion 84 of the coolant hose 80. The fourth portion 84 is a part of the cooling water hose 80 routed between the third portion 83 and the heat exchanger unit 13, and does not adhere to the urea water hose 69.

  The fifth portion 85 is a part of the cooling water hose 80 used for cooling the urea water injection device 68. When the engine coolant having a temperature lower than that of the high temperature urea water injection device 68 flows through the fifth portion 85, the engine water takes heat from the high temperature urea water injection device 68 and cools the urea water injection device 68 to prevent overheating. . After that, when the engine cooling water that has been supplied with heat and has a relatively high temperature (higher than the urea water) flows through the sixth portion 86 (a part of the fifth portion 85) along the urea water hose 69, Heat is supplied to the urea water hose 69 and the urea water therein. When the urea water injection device 68 is in a low temperature state, the engine coolant having a temperature higher than that of the urea water injection device 68 in the low temperature state flows through the fifth portion 85, and the urea water injection device 68 and the urea water in the inside thereof. To supply heat. Thereafter, the engine coolant that has reached a relatively low temperature after the supply of heat in the sixth portion 86 has merged with the engine coolant that has flowed through the third portion 83, and then passes through the fourth portion 84 to generate heat. The switch unit 13 is reached.

  In this way, the heat supply mechanism supplies heat to the urea water tank 9, the urea water hose 69, the supply module SM, and the urea water injection device 68 using the engine cooling water, and the urea water inside them. Is prevented from being frozen, or frozen urea water is dissolved.

  Next, an example of an output image displayed on the monitor 77 will be described with reference to FIG. FIG. 4 shows a main screen displayed on the monitor 77 when the asphalt finisher 100 is activated. As shown in FIG. 4, the main screen mainly includes display units G1 to G30.

  The display unit G1 displays the accumulated engine operating time. The display unit G2 displays a text message. The display unit G3 displays the state of communication sensitivity. The display unit G4 displays the current time.

  The display part G5 displays the position state of the steering wheel. For example, the display unit G5 displays the rotation direction and rotation angle of the steering wheel in seven divisions. In the example of FIG. 4, the display unit G5 shows a state in which the steering handle is slightly rotated in the right direction.

  The display unit G6 displays a warm-up lamp that is lit during the thawing and heat retention of the urea water. The display unit G7 displays an output limiting lamp that is turned on when the engine output is limited. The display unit G8 displays an ECO mode lamp that is lit when the ECO mode switch is on. When the ECO mode switch is turned on, the engine speed is reduced to the ECO mode, and the fuel consumption is suppressed. The display unit G9 displays a non-spin control lamp that is turned on during non-spin control. The non-spin control is a control for preventing a situation in which one side of the rear wheel slips and hydraulic oil does not flow to the driving motor on the opposite side and the driving force is lost. Specifically, when detecting the slip, the controller 30 blocks the flow of hydraulic oil to the slipping traveling motor and causes the hydraulic fluid to flow only to the opposite traveling motor.

  The display unit G10 displays a travel mode lamp indicating the travel mode. In the example of FIG. 4, the display unit G10 displays a state where the low speed 2WD mode is selected. The display unit G11 displays a parking brake lamp that is lit when the parking brake is operating. The display unit G12 displays a rear controller lamp that is turned on when the rear controller is enabled. The rear controller is an optional operation panel different from the operation panel installed in the driver's seat. In this example, the rear controller is installed at the rear part of the screed 3. When the rear controller is enabled, the operation panel installed in the driver's seat is disabled.

  The display unit G13 displays a urea water meter that indicates the remaining amount of urea water. The display unit G14 displays an engine water temperature meter that indicates the temperature of the engine cooling water. The display unit G15 displays a hydraulic oil thermometer that indicates the temperature of the hydraulic oil. The display unit G16 displays a fuel gauge that indicates the remaining amount of fuel.

  The display unit G17 displays the current engine speed of the engine 6. The display unit G18 displays the set speed (set travel speed) set by the travel dial. The display unit G19 displays the current traveling speed of the asphalt finisher 100.

  The display unit G20 displays an actual measurement value of the tamper rotation number measured by the rotation sensor. The display unit G21 displays an actual measurement value of the vibrator rotation speed measured by the rotation speed sensor. As described above, the main screen simultaneously displays the actual measurement values of the tamper speed and the vibrator speed. The display unit G22 displays a screed temperature that is a measurement value of a temperature sensor installed in the screed 3.

  The display unit G23 displays a menu switch for calling a menu screen. The display unit G24 displays a brake steer switch for calling a brake steer operation screen. The brake steer operation screen is a screen for executing a brake steer operation in which the rear wheel is braked to make a sudden turn.

  The display unit G25 displays a front wheel driving force switching switch for switching the front wheel driving force. The display unit G26 displays a regeneration switch for starting manual regeneration of the exhaust gas aftertreatment device 7. The display unit G27 displays a camera video display switch for displaying a camera video.

  The display unit G28 displays an error display switch for displaying a detailed screen regarding the details of the error when an error has occurred. The display unit G29 displays an emergency operation switch for switching to an emergency operation mode for operating the asphalt finisher 100 through the monitor 77 instead of the switch on the operation panel. The display unit G30 displays a hazard lamp switch for blinking the left and right direction indicators.

  Next, another example of an output image displayed on the monitor 77 will be described with reference to FIG. FIG. 5 shows a camera video display screen displayed on the monitor 77 when the camera video display switch of the display unit G27 is pressed on the main screen shown in FIG.

  As shown in FIG. 5, the camera image display screen displays the camera image CG, the positions of the display units G6 to G18 are changed, the display of the display units G19 to G24, G27, G29, and G30 is omitted, and 4 is different from the main screen in FIG. 4 in that the display units G31 to G40 are newly displayed. Therefore, the difference will be described in detail. In the example of FIG. 5, a text message “SCR automatic playback in progress” indicating that the SCR system is being automatically played back is displayed on the display unit G2. The display units G31 to G38 can also be displayed on the main screen. Further, the camera image CG is an image when one camera attached to the front end of the tractor 1 images the inside of the hopper 2. The camera image CG may be a viewpoint conversion image generated by combining images captured by a plurality of cameras.

  The display unit G31 displays a purge lamp indicating the SCR state. In the example of FIG. 5, the fact that automatic reproduction is in progress is displayed in a green lighting state.

  The display unit G32 displays an abnormal level lamp indicating an abnormal level related to the SCR system. In the example of FIG. 5, the display unit G32 displays an icon indicating that an abnormality relating to the SCR system has occurred. The display unit G33 displays a replenishment lamp indicating a state where urea water needs to be replenished. In the example of FIG. 5, the display unit G33 displays a text message that prompts replenishment of urea water.

  The display part G34 and the display part G35 display a message regarding an abnormality of the SCR system. In the example of FIG. 5, the display unit G34 displays an icon and a text message indicating that an abnormality relating to the SCR system has occurred. The display unit G35 displays an icon and a text message indicating that the operation of the asphalt finisher 100 is restricted due to an abnormality in the SCR system.

  The display unit G36 displays a text message that makes it conspicuous that an error has occurred. In the example of FIG. 5, “Error occurrence!” Is displayed.

  The display unit G37 displays an arrow that prompts the user to press the error display switch of the display unit G28 when an error occurs.

  The display unit G38 displays a text message indicating the state of the asphalt finisher 100. In the example of FIG. 5, “in screed detach mode” is displayed. The display unit G39 displays an enlargement switch for enlarging and displaying the camera image CG. When the enlargement switch is pressed, the camera image CG is displayed on the full screen, for example. The display unit G40 displays a return switch for returning the current output image to the previous output image.

  Next, processing when the controller 30 detects an abnormal state related to the SCR system (hereinafter referred to as “processing when detecting abnormality”) will be described with reference to FIG. 6. FIG. 6 is a flowchart showing the flow of the abnormality detection process. The controller 30 repeatedly executes this abnormality detection process at a predetermined control cycle.

  Initially, the controller 30 determines whether it is a 1st abnormal state (step ST1). The first abnormal state is an abnormal state related to the SCR system. For example, the remaining amount of urea water is less than a predetermined first remaining amount, and the concentration of urea water measured by the urea water concentration sensor 74A is a predetermined first concentration. Less than the above, and a state where an electrical abnormality has occurred in the SCR system.

  When it determines with it being a 1st abnormal state (YES of step ST1), the controller 30 sets the operation state of the asphalt finisher 100 to warning mode (step ST2).

  The warning mode is a mode for notifying the operator of the asphalt finisher 100 that the first abnormal state has occurred. In the warning mode, for example, the controller 30 turns on an abnormal level lamp that indicates the level of abnormality relating to the SCR system on the display unit G32, and lights a supply lamp that indicates a state in which urea water needs to be supplied on the display unit G33. Let Even if the remaining amount and concentration of urea water are both normal, if an electrical abnormality occurs in the SCR system, the controller 30 may display a text message indicating that on the display unit G34. Good.

  When it determines with it not being a 1st abnormal state (NO of step ST1), the controller 30 performs a subsequent step, without making the operation state of the asphalt finisher 100 into warning mode.

  Thereafter, the controller 30 determines whether or not the second abnormal state is present (step ST3). The second abnormal state is an abnormal state related to the SCR system, and is an abnormal state having a higher warning level than the first abnormal state. The second abnormal state is, for example, a state in which the remaining amount of urea water is less than a predetermined second remaining amount that is less than the first remaining amount, or a state in which the concentration of urea water is less than a predetermined second concentration that is lower than the first concentration , A state in which a predetermined first time has elapsed since the detection of the first abnormal state, a state in which the same abnormal state is detected again within a predetermined time, and the like.

  When it determines with it being a 2nd abnormal state (YES of step ST3), the controller 30 sets the operation state of the asphalt finisher 100 to the early elimination promotion mode (step ST4).

  The early elimination promotion mode is a mode that prompts the operator of the asphalt finisher 100 to eliminate the abnormal state of the SCR system at an early stage. The “early stage” is a stage in which only a small limit is required for the operation of the asphalt finisher 100 and a large limit is not necessary.

  In the early elimination promotion mode, for example, the controller 30 limits the output of the engine 6 to a predetermined first output (for example, 70 [%]) or less in addition to the processing performed in the warning mode. Further, the abnormal level lamp blinks at a relatively long interval on the display unit G32, and the output limiting lamp is turned on on the display unit G7. Further, the controller 30 executes a horsepower reduction process described later. Note that the horsepower reduction process may be executed in a warning mode.

  The presence of the warning mode and the early elimination promotion mode makes it easy for the operator of the asphalt finisher 100 to schedule a time for performing work for eliminating the abnormal state of the SCR system, such as urea water supply.

  When it determines with it not being a 2nd abnormal state (NO of step ST3), the controller 30 performs a subsequent step, without setting the operation state of the asphalt finisher 100 to the early elimination promotion mode.

  Thereafter, the controller 30 determines whether or not it is in the third abnormal state (step ST5). The third abnormal state is an abnormal state related to the SCR system, and is an abnormal state having a higher warning level than the second abnormal state. The third abnormal state is, for example, a state in which the remaining amount of urea water is less than a predetermined third remaining amount that is less than the second remaining amount, and a concentration of urea water is less than a predetermined third concentration that is lower than the second concentration. And a state where a predetermined second time has elapsed since the detection of the second abnormal state.

  When it is determined that the state is the third abnormal state (YES in step ST5), the controller 30 sets the operation state of the asphalt finisher 100 to the final elimination promotion mode (step ST6).

  The final elimination promotion mode is a mode that prompts the operator of the asphalt finisher 100 to eliminate the abnormal state of the SCR system in the final stage. The “final stage” is a stage in which a great restriction is imposed on the operation of the asphalt finisher 100.

  In the final elimination promotion mode, for example, the controller 30 limits the output of the engine 6 to a predetermined second output (for example, 60 [%]) lower than the first output in addition to the processing performed in the early elimination promotion mode, In addition, the rotational speed of the engine 6 is reduced to a predetermined rotational speed (for example, idling rotational speed). Further, the abnormal level lamp blinks at a relatively short interval on the display unit G32. Further, a text message indicating that the construction cannot be continued is displayed on the display unit G35. Further, the controller 30 may execute a horsepower reduction process described later.

  In this way, the controller 30 informs the operator that an abnormal state related to the SCR system has occurred, or restricts the operation of the asphalt finisher 100 according to the warning level of the abnormal state, thereby allowing the operator to perform an abnormal state. Can be urged to eliminate.

  In the above-described embodiment, the controller 30 determines the abnormal state of the SCR system in three stages, but may determine in two stages or less, or may determine in four or more stages.

  Next, a process when the escape mode is selected (hereinafter referred to as “escape process”) will be described with reference to FIG. FIG. 7 is a flowchart showing the flow of escape processing. The controller 30 executes this escape process when the operation state of the asphalt finisher 100 is in the early elimination promotion mode.

  First, the controller 30 determines whether or not the escape mode is turned on (step ST11). In the example of FIG. 7, the controller 30 determines that the escape mode is turned on when an escape switch as a selection device in the input device attached to the monitor 77 is pressed. When the monitor 77 is a touch panel, the escape switch may be a software button.

  If it is determined that the escape mode is not turned on (NO in step ST11), the controller 30 repeats the determination in step ST11 until it is determined that the escape mode is turned on.

  If it is determined that the escape mode is turned on (YES in step ST11), the controller 30 returns the asphalt finisher 100 to the normal operation state (step ST12).

  In the example of FIG. 7, the controller 30 releases the output restriction of the engine 6. Specifically, the maximum output of the engine 6 limited to the first output or less is increased to 100 [%]. In addition, the controller 30 causes the display unit G34 to display a text message indicating that the operating state of the asphalt finisher 100 is the escape mode.

  Thereafter, the controller 30 monitors the elapsed time after starting the escape mode and the remaining amount of urea water (step ST13).

  When the elapsed time exceeds the predetermined time T1, or when the remaining amount of urea water falls below the predetermined remaining amount Vm (YES in step ST13), the controller 30 resumes the output restriction of the engine 6. Specifically, the controller 30 sets the operation state of the asphalt finisher 100 again to the early elimination promotion mode, and restricts the output of the engine 6 to the first output or less. Further, the text message indicating the escape mode in the display unit G34 is deleted.

  The predetermined remaining amount Vm is larger than the second remaining amount used as the condition for the second abnormal state. Further, the number of times that the escape mode can be turned on may be limited by one time, may be limited by a predetermined number of times of two or more, or may be unlimited.

  With this configuration, the operator of the asphalt finisher 100 limits the output of the engine 6 due to the start of the early elimination promotion mode due to urea water shortage, urea water quality abnormality (concentration abnormality), system abnormality of the SCR system, and the like. Even if it is a case, the restriction | limiting of the engine 6 can be lifted temporarily as needed.

  Next, referring to FIG. 8, processing when an abnormal state related to the remaining amount of urea water is detected (an example of processing at the time of abnormality detection, hereinafter referred to as “processing at the time of residual amount abnormality detection”) will be described. FIG. 8 is a flowchart showing the flow of the process when the remaining amount abnormality is detected. The controller 30 repeatedly executes this remaining amount abnormality detection process at a predetermined control cycle.

  First, the controller 30 determines whether or not the remaining amount of urea water is less than the first remaining amount V1 (step ST21). In the example of FIG. 8, the controller 30 determines whether the remaining amount of urea water is less than the first remaining amount V <b> 1 based on the measurement value of the urea water remaining amount sensor 74.

  If it is determined that the remaining amount of urea water is less than the first remaining amount V1 (YES in step ST21), the controller 30 limits the engine torque and starts a horsepower reduction process (step ST22). This process corresponds to the process of determining the second abnormal state in FIG. 6 and executing the early elimination promotion mode.

  The horsepower reduction process is a process of limiting the engine load in order to prevent the engine 6 from being stopped by limiting the engine torque, and details thereof will be described later.

  In the example of FIG. 8, the controller 30 limits the torque that the engine 6 can output to A1 [%] or less of the maximum torque. Further, the controller 30 displays a text message “urea water supply” on the display unit G2.

  When it is determined that the remaining amount of urea water is equal to or greater than the first remaining amount V1 (NO in step ST21), the controller 30 does not limit the engine torque and does not start the horsepower reduction process. Execute the process.

  Thereafter, the controller 30 determines whether or not the remaining amount of urea water is less than the second remaining amount V2 (step ST23). In the example of FIG. 8, the controller 30 determines whether or not the remaining amount of urea water is less than the second remaining amount V2 based on the measured value of the remaining urea water sensor 74.

  When it is determined that the remaining amount of urea water is less than the second remaining amount V2 (YES in step ST23), the controller 30 further restricts the engine torque and restricts the engine speed (step ST24). This process corresponds to the process of determining the third abnormal state in FIG. 6 and executing the final elimination promotion mode. The horsepower reduction process already started is continuously executed as it is.

  In the example of FIG. 8, the controller 30 limits the torque that can be output by the engine 6 to A2 [%] (<A1 [%]) or less of the maximum torque. Further, the engine speed is reduced to the idling speed.

  When it is determined that the remaining amount of urea water is equal to or greater than the second remaining amount V2 (NO in step ST23), the controller 30 does not perform additional limitation of engine torque and limitation of engine speed, The process when the remaining amount abnormality is detected is terminated.

  Here, the horsepower reduction process will be described with reference to FIG. FIG. 9 is a flowchart showing the flow of horsepower reduction processing. The controller 30 repeatedly executes this horsepower reduction process at a predetermined control cycle. The horsepower reduction process is stopped, for example, when urea water is supplied.

  First, the controller 30 calculates the engine torque margin (step ST31). The engine torque margin is a value obtained by subtracting the ratio of the torque that the engine 6 is currently outputting from the ratio of the torque that the engine 6 can output to the maximum torque. For example, when the torque that the engine 6 can output is limited to A1 [%] of the maximum torque, if the torque that the engine 6 is currently outputting is B [%] of the maximum torque, the margin is (A1 -B) [%].

  Thereafter, the controller 30 determines whether or not the margin is less than the threshold value THe (step ST32). In the example of FIG. 9, the margin (A1-B) [%] calculated as described above is compared with a threshold value THe stored in advance in a ROM or the like.

  When it is determined that the margin is less than the threshold value THe (YES in step ST32), the controller 30 limits the machine side (step ST33). In the example of FIG. 9, the controller 30 reduces the output horsepower (absorption horsepower) of the hydraulic pump. This is to prevent the engine 6 from stopping because the output horsepower (absorption horsepower) of the hydraulic pump exceeds the output horsepower of the engine 6.

  Specifically, for example, the controller 30 limits the operating speed of at least one of the conveyor 10 and the screw 11 driven by the conveyor / screw pump 14S.

  Alternatively, the controller 30 may limit the rotational speeds of the left rear wheel traveling motor 20L and the right rear wheel traveling motor 20R driven by the rear wheel traveling pump 14R.

  Alternatively, the controller 30 may stop the generator motor 42G driven by the conveyor / screw pump 14S. Even if the power generation by the generator 43 is stopped due to the stop of the generator motor 42G and the power supply to the heater is stopped, the temperature of the heating required part is maintained to some extent by the heat of the paving material during the construction. It is.

  FIG. 10 is a diagram showing the relationship between the engine torque margin and the machine-side limit. The controller 30 increases the limit amount on the machine side when the margin is less than the threshold value THe. An increase in the limit amount on the machine side means a reduction in the maximum horsepower that the hydraulic pump can output. That is, the relationship of FIG. 10 indicates that the maximum horsepower that can be output by the hydraulic pump is limited as the margin decreases with the predetermined value M1 to the threshold value THe. Further, when the margin is less than the predetermined value M1, the limit amount also reaches a peak at the predetermined level R1, and the reduction range of the maximum horsepower that can be output by the hydraulic pump also reaches a peak.

  As described above, the controller 30 limits the output of the engine 6 in order to prevent the engine 6 from being stopped when the output of the engine 6 is limited due to insufficient urea water remaining. Accordingly, the output horsepower of the hydraulic pump is reduced.

  The maximum horsepower reduction range (total reduction range) that the hydraulic pump can output is, for example, the maximum horsepower reduction range (first reduction range) that can be output by the conveyor screw pump 14S and the rear wheel traveling pump 14R. This is the sum of the reduction range of the maximum horsepower (second reduction range). For example, the controller 30 may adjust the first reduction width and the second reduction width individually to realize the required total reduction width.

  Further, the controller 30 has a hysteresis in the limit amount in order to prevent the operation of the asphalt finisher 100 from becoming unstable due to an unstable engine torque margin calculated every predetermined control cycle. You may make it let. For example, the “margin” in step ST32 may be an average value of a plurality of margins calculated over a predetermined time.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  DESCRIPTION OF SYMBOLS 1 ... Tractor 1a ... Engine hood 1b ... Exterior cover 2 ... Hopper 2a ... Hopper cylinder 3 ... Screed 3a ... Leveling arm 4 ... Front wheel 5 ... Rear wheel 6 ... Engine 6a ... Air filter 6b ... Intake pipe 6c ... Exhaust pipe 7 ... Exhaust gas aftertreatment device 7a ... First treatment part 7b ... Second treatment part 8. .... Fuel tank 9 ... Urea water tank 10 ... Conveyor 11 ... Screw 13 ... Heat exchanger unit 14 ... Hydraulic source 14C ... Charge pump 14C 14R ... Rear wheel running pump 14S ... Conveyor screw pump 15, 15A ... Pump regulator 20L ... Left rear wheel travel motor 20R ... Right rear wheel travel motor 20La, 20R ... Check valve 20Lb, 20Rb ... Relief valve 21L, 21R ... Reduction ratio control device 22L, 22R ... Brake control device 30 ... Controller 41 ... Control valve 42SL ... Left screw motor 42SL 42SR ... right screw motor 42CL ... left conveyor motor 42CR ... right conveyor motor 42G ... generator motor 43 ... generator 60 ... engine control module 61 ... turbocharger 63 ... Connection part 65 ... Intercooler 68 ... Urea water injection device 69 ... Urea water hose 70 ... Urea water supply pump 71 ... Filter 72 ... First NOx sensor 73 ... Second NOx sensor 74 ... urea water remaining amount sensor 74A ... urea water concentration sensor 75 ... exhaust gas controller 77 ... monitor 80 ... cooling water hose 81 ... first part 82 ... second part 83 ... third part 84 ... fourth part 85 ... 5th part 86 ... 6th part 100 ... Asphalt finisher 150 ... Exhaust gas aftertreatment system C1, C2 ... Pipe line CG ... Camera image F1 ... Rear wheel drive part F2, ...・ Conveyor screw drive part G1-G40 Display part SM ・ ・ ・ Supply module

Claims (11)

A tractor,
A hopper installed on the front side of the tractor;
A conveyor for conveying the paving material in the hopper to the rear side of the tractor;
A screw that spreads the paving material conveyed by the conveyor and spread on the road surface in the vehicle width direction; and
A screed that spreads the paving material spread by the screw on the rear side of the screw,
An engine mounted on the tractor;
A hydraulic pump driven by the engine;
An exhaust gas aftertreatment device for purifying the exhaust gas of the engine;
A control device that reduces the output of the engine and reduces the output horsepower of the hydraulic pump when an abnormality of the exhaust gas aftertreatment device is detected;
Asphalt finisher. The control device limits the operating speed of the screw and the conveyor driven by the hydraulic pump when an abnormality of the exhaust gas aftertreatment device is detected,
The asphalt finisher according to claim 1. The controller limits the rotational speed of a traveling hydraulic motor driven by the hydraulic pump when an abnormality of the exhaust gas aftertreatment device is detected;
The asphalt finisher according to claim 1 or 2. A generator for supplying power to the heater;
A generator hydraulic motor that rotationally drives the generator, and
The controller stops the generator hydraulic motor driven by the hydraulic pump when an abnormality of the exhaust gas aftertreatment device is detected;
The asphalt finisher according to any one of claims 1 to 3. A selection device that enables selection of an operation mode,
The control device increases the output of the engine that is reduced when the escape mode is selected as the operation mode through the selection device;
The asphalt finisher according to any one of claims 1 to 4. The control device reduces the output of the engine when a predetermined time has elapsed since the escape mode was selected.
The asphalt finisher according to claim 5. Reducing the engine output includes reducing only engine torque, and reducing engine torque and engine speed.
The asphalt finisher according to any one of claims 1 to 6. The abnormality of the exhaust gas aftertreatment device includes an abnormality of the remaining amount of urea water,
The control device reduces the output of the engine when the remaining amount of urea water falls below a first predetermined value, and the remaining amount of urea water falls below a second predetermined value that is smaller than the first predetermined value. Reducing the output of the engine and reducing the output horsepower of the hydraulic pump,
The asphalt finisher according to any one of claims 1 to 7. The remaining amount of urea water is displayed on the screen together with the remaining amount of fuel and the engine speed.
The asphalt finisher according to claim 8. On the screen, the tamper speed and the vibrator speed are displayed simultaneously.
The asphalt finisher according to claim 9. When the abnormality of the urea water is detected, the control device displays that fact on the screen.
The asphalt finisher according to claim 9 or 10.