Working vehicle and working vehicle control method

Abstract

A working vehicle is provided with a hydraulic pump is driven using an engine. A hydraulic actuator is driven using hydraulic fluid which is discharged from the hydraulic pump. A power generator motor driven using the engine. An electric actuator is driven using electrical power which is generated using the power generator motor. An exhaust processing apparatus cleans exhaust from the engine. A reducing agent tank retains reducing agent which is supplied to the exhaust processing apparatus. A retention amount detecting section detects the retention amount of the reducing agent inside the reducing agent tank. An engine control section performs output restriction control where the output of the engine is reduced when the retention amount is equal to or less than a first threshold. The electric actuator control section restricts the output of the electric actuator during executing of the output restriction control.

1 . A working vehicle comprising:
 an engine;   a hydraulic pump driven by the engine;   a hydraulic actuator driven by a hydraulic fluid discharged from the hydraulic pump;   a power generator driven by the engine;   an electric actuator driven by electrical power generated by the power generator;   an exhaust processing apparatus which cleans an exhaust from the engine;   a reducing agent tank which retains a reducing agent supplied to the exhaust processing apparatus;   a retention amount detecting section which detects a retention amount of the reducing agent inside the reducing agent tank;   an engine control section which performs an output restriction control in which an output of the engine is reduced when the retention amount is equal to or less than a first threshold; and   an electric actuator control section which restricts an output of the electric actuator during executing of the output restriction control: and   an electrical power control apparatus electrically connected with the power generator and the electric actuator,   the electric actuator control section stopping the electric actuator when the retention amount is equal to or less than a second threshold which is smaller than the first threshold; and   the electric actuator control section stopping the electrical power control apparatus when the retention amount is equal to or less than the second threshold and predetermined system stop conditions are satisfied.   
     
     
         2 . A working vehicle comprising:
 an engine;   a hydraulic pump driven by the engine;   a hydraulic actuator driven by a hydraulic fluid discharged from the hydraulic pump:   a power generator driven by the engine:   an electric actuator driven by electrical power generated by the power generator;   an exhaust processing apparatus which cleans an exhaust from the engine;   a reducing agent tank which retains a reducing agent supplied to the exhaust processing apparatus;   a retention amount detecting section which detects a retention amount of the reducing agent inside the reducing agent tank;   an engine control section which performs an output restriction control in which an output of the engine is reduced when the retention amount is equal to or less than a first threshold;   an electric actuator control section which restricts an output of the electric actuator during executing of the output restriction control;   an output calculating section which calculates the output of the power generator which is necessary for driving the electric actuator when the retention amount is equal to or less than the first threshold;   an absorption torque determining section which determines an absorption torque of the hydraulic pump based on the output of the engine which is reduced and the restricted output of the power generator which is necessary for driving the electric actuator which is restricted; and   a pump control section which controls the hydraulic pump with the determined absorption torque.   
     
     
         3 . The working vehicle according to  claim 2 , wherein
 the electric actuator control section stops the electric actuator when the retention amount is equal to or less than a second threshold which is smaller than the first threshold.   
     
     
         4 . The working vehicle according to  claim 3 , further comprising
 an electrical power control apparatus electrically connected with the power generator and the electric actuator,   the electric actuator control section stopping the electrical power control apparatus when the retention amount is equal to or less than the second threshold and predetermined system stop conditions are satisfied.   
     
     
         5 . The working vehicle according to  claim 4 , wherein
 the predetermined system stop conditions include the operation speed of the electric actuator being reduced to a predetermined speed.   
     
     
         6 . The working vehicle according to  claim 5 , wherein
 the predetermined system stop conditions further include a torque command value to the power generator being zero.   
     
     
         7 . The working vehicle according to  claim 1 , wherein
 the electric actuator control section sets the torque command value to the electric actuator to zero when the retention amount is equal to or less than the second threshold.   
     
     
         8 . The working vehicle according to  claim 1 , wherein
 the engine control section controls the output of the engine with a first engine torque curve during normal periods in which the retention amount is larger than the first threshold, and   the engine control section controls the output of the engine during the output restriction control with a second engine torque curve which stipulates that the output of the engine is lower than in the first engine torque curve.   
     
     
         9 . The working vehicle according to  claim 1 , wherein
 the electric actuator control section reduces an upper limit for the output torque of the electric actuator during the output restriction control.   
     
     
         10 . The working vehicle according to  claim 1 , further comprising
 a traveling body; and   a revolving body swingably supported by the traveling body,   the electric actuator being an electric motor which revolves the revolving body.   
     
     
         11 . A working vehicle control method comprising:
 determining a retention amount of a reducing agent inside a reducing agent tank;   performing an output restriction control in which a signal which reduces an output of an engine is output when the retention amount is equal to or less than a first threshold;   outputting a signal for restricting an output of an electric actuator during execution of the output restriction control;   calculating an output of a power generator which is necessary for driving the electric actuator;   determining an absorption torque of a hydraulic pump based on the output of the engine which is reduced and the restricted output of the power generator which is necessary for driving the electric actuator which is restricted; and   outputting a command signal which indicates the absorption torque of the hydraulic pump which is determined.   
     
     
         12 . A working vehicle control method comprising:
 determining a retention amount of a reducing agent inside a reducing agent tank;   performing an output restriction control in which a signal which reduces an output of an engine is output when the retention amount is equal to or less than a first threshold:   outputting a signal for restricting an output of an electric actuator during execution of the output restriction control;   calculating an output of a power generator which is necessary for driving the electric actuator;   determining an absorption torque of a hydraulic pump based on the output of the engine which is reduced and the output of the power generator which is necessary for driving the electric actuator; and   outputting a command signal which indicates the absorption torque of the hydraulic pump which is determined;   outputting a stop command to the electric actuator when the retention amount is equal to or less than a second threshold which is smaller than the first threshold; and   outputting a stop signal for an electric power control apparatus for the power generator and the electric actuator when an operation speed of the electric actuator is reduced to a predetermined speed and a torque command value to the power generator is zero after outputting the stop command.   
     
     
         13 . (canceled)