Abstract: An engine control device for work vehicle includes: a target rotation speed setting unit that sets a target rotation speed of an engine corresponding to an operation amount of an accelerator pedal; a rotation speed control unit that controls a rotation speed of the engine according to the target rotation speed; a travel driving unit that transmits rotation of the engine to wheels via a torque converter; a speed ratio detection unit that detects a speed ratio between an input shaft and an output shaft of the torque converter; and a target rotation speed correction unit that corrects the target rotation speed set by the target rotation speed setting unit so as to increase the target rotation speed based on the speed ratio when the operation amount of the accelerator pedal is smaller than a predetermined value and the speed ratio detected by the speed ratio detection unit is smaller than a predetermined value within a range which is equal to or greater than 0 and less than 1.

Abstract: A clutch control device for a work vehicle includes a determination unit that determines as to whether or not a clutch cutoff condition has been established based upon whether or not the accelerator pedal is being operated, as determined by the accelerator pedal operation determination unit, the vehicle speed of the work vehicle detected by the vehicle speed detection unit and the braking force of the work vehicle detected by the braking force detection unit; and a clutch control unit that controls engagement/release of a clutch so as to release the clutch when the determination unit determines that the clutch cutoff condition has been established.

Abstract: A cooling fan control unit, in response to an operation performed at the rotation direction selector switch to select a reverse rotation setting while the cooling fan is rotating forward, lowers a relief pressure setting at the variable relief valve to a predetermined lower limit value over a predetermined length of time, and once the discharge pressure at the hydraulic pump detected by the pressure sensor is lowered to a predetermined switch-over pressure, executes control so as to switch the direction of flow of pressure oil to the hydraulic motor to the reverse direction by switching the direction switching valve and raises the relief pressure setting at the variable relief valve to a reverse rotation pressure setting, at which the hydraulic motor rotates in the reverse direction, over a predetermined length of time.

Abstract: A work vehicle including a front work device, contains: a variable displacement hydraulic pump that is driven by an engine and supplies pressure oil to an actuator that drives the front work device; an exhaust gas purification device that purifies nitrogen oxide in exhaust gas discharged from the engine using a reducing agent solution stored in a reducing agent tank; a remaining amount detection device that detects a remaining amount of the reducing agent solution in the reducing agent tank; and a control unit that decreases output torque of the engine and also decreases a rotational speed of the engine in a rated point according to decrease of the remaining amount of the reducing agent solution detected by the remaining amount detection device.

Abstract: A prime mover control device for a work vehicle, includes: a rotation speed control unit that controls a rotation speed of a prime mover in correspondence to an operation quantity of an accelerator operation member; a temperature detection unit that detects a temperature of cooling oil used to cool a brake; and a speed limiting unit that limits a maximum rotation speed of the prime mover by setting a lower limit for the maximum rotation speed when the temperature of the cooling oil detected by the temperature detection unit is higher than a predetermined temperature, compared to a limit set when the temperature of the cooling oil detected by the temperature detection unit is lower than the predetermined temperature, wherein: a maximum vehicle speed is limited by limiting the maximum rotation speed of the prime mover by the speed limiting unit.

Abstract: A work vehicle equipped with an HST traveling drive device, includes: an operation quantity detector that detects an operation quantity representing an extent to which an accelerator pedal is operated; a rotation rate detector that detects an actual rotation rate at a prime mover; a requested rotation rate calculation unit that calculates a requested rotation rate for the prime mover based upon the operation quantity detected by the operation quantity detector; and a prime mover control unit that controls the actual rotation rate based upon the requested rotation rate calculated by the requested rotation rate calculation unit. When the requested rotation rate is higher than a predetermined value, the requested rotation rate calculation unit calculates a rate of acceleration for the requested rotation rate based upon a difference between the requested and the actual rotation rate detected by the rotation rate detector and calculates the requested rotation rate based upon the calculated rate of acceleration.

Abstract: To provide a travel control device for a working vehicle, including a speed change lever that is applicable even when a transmission in which speed stages are set to be larger by one stage is applied, the travel control device comprises a switching device (41) that switches speed changed by a transmission (3) either manually or automatically, a speed stage selecting device (30b) that selects a speed stage out of a plurality of speed stages of the transmission (3), and a first speed selecting device (40) that changes the speed stage manually down to a first speed separately from the speed stage selecting device (30b), regardless of a switching state of the switching device (41), wherein the speed stage selecting device (30b) selects the speed stages including a second speed or more but excluding the first speed, and a control device (10) is further provided, which controls the transmission (3) based on instructions sent from the switching device (41), the speed stage selecting device (30b), and the first speed

Abstract: A construction machine includes a condenser 24 for cooling refrigerant for an air conditioner; a fan 21 for cooling the condenser 24 by using forward cooling air produced during normal-rotation drive; other cooled objects such as a radiator 25 and the like disposed under the lee of the forward cooling air with respect to the condenser 24; a refrigerant pressure detector 27 for detecting the pressure of the refrigerant flowing in the condenser 24; and a controller 136 for executing reverse-rotation stop processing for returning the fan 21 to the normal-rotation drive when the pressure P of the air conditioner refrigerant detected by the refrigerant pressure detector 27 reaches a preset normal-rotation return pressure P1 during reverse-rotation drive of the fan 21. Thus, the lowering of the cooling effect of an air conditioner can be suppressed while reducing the burden of cleaning an engine room.

Abstract: To provide a travel control device for a working vehicle, including a speed change lever that is applicable even when a transmission in which speed stages are set to be larger by one stage is applied, the travel control device comprises a switching device (41) that switches speed changed by a transmission (3) either manually or automatically, a speed stage selecting device (30b) that selects a speed stage out of a plurality of speed stages of the transmission (3), and a first speed selecting device (40) that changes the speed stage manually down to a first speed separately from the speed stage selecting device (30b), regardless of a switching state of the switching device (41), wherein the speed stage selecting device (30b) selects the speed stages including a second speed or more but excluding the first speed, and a control device (10) is further provided, which controls the transmission (3) based on instructions sent from the switching device (41), the speed stage selecting device (30b), and the first speed

Abstract: When a vehicle speed of a wheel loader (1) is determined to be not higher than a reference value (Yes) in step S4 and a forward/reverse command switch (40) is determined to have been switchingly operated (Yes) in step S5, the routine advances to step S6 where an increment ?N of engine speed according to an engine load factor is determined. In step S7, the increment ?N of engine speed is then added to a target engine speed Na corresponding to a depression stroke of an accelerator pedal (38), the thus-determined Na=Na+?N is set as a new target engine speed Na, and a target engine speed command i1 is sent to an engine controller (37).

Abstract: A work vehicle includes: a hydraulic pump driven by an engine; a rotational speed detection unit that detects an actual rotational speed of the engine; an exhaust gas purification device that purifies nitrogen oxide in exhaust gas discharged from the engine using a reducing agent solution stored in a reducing agent tank; a torque control unit that decreases output torque of the engine according to decrease of a detected remaining amount of the reducing agent solution; and a storage device that stores a threshold value not less than an engine rotational speed at which the hydraulic pump starts discharge, wherein when the actual rotational speed of the engine is not more than the threshold value, the torque control unit does not decrease the output torque of the engine regardless of the remaining amount of the reducing agent solution detected by the remaining amount detection device.

Abstract: A work vehicle including a front work device, contains: a variable displacement hydraulic pump that is driven by an engine and supplies pressure oil to an actuator that drives the front work device; an exhaust gas purification device that purifies nitrogen oxide in exhaust gas discharged from the engine using a reducing agent solution stored in a reducing agent tank; a remaining amount detection device that detects a remaining amount of the reducing agent solution in the reducing agent tank; and a control unit that decreases output torque of the engine and also decreases a rotational speed of the engine in a rated point according to decrease of the remaining amount of the reducing agent solution detected by the remaining amount detection device.

Abstract: An engine control device for work vehicle includes: a target rotation speed setting unit that sets a target rotation speed of an engine corresponding to an operation amount of an accelerator pedal; a rotation speed control unit that controls a rotation speed of the engine according to the target rotation speed; a travel driving unit that transmits rotation of the engine to wheels via a torque converter; a speed ratio detection unit that detects a speed ratio between an input shaft and an output shaft of the torque converter; and a target rotation speed correction unit that corrects the target rotation speed set by the target rotation speed setting unit so as to increase the target rotation speed based on the speed ratio when the operation amount of the accelerator pedal is smaller than a predetermined value and the speed ratio detected by the speed ratio detection unit is smaller than a predetermined value within a range which is equal to or greater than 0 and less than 1.

Abstract: Provided is a work vehicle which is capable of appropriately setting the height of a work tool as a control threshold value for a ride control device or an automatic transmission control device, and which is excellent in operability, travel stability, and work efficiency. A value detected by an angle sensor (39) when a signal import switch (46) is operated by an operator is stored in a height position storage unit (35b) of a main controller (35) as height position information about a bucket (13) for excavation work. In the height position storage unit (35b), the height position of the bucket (13) for hauling work and the height position of the bucket (13) for loading work are stored in advance as offset values from the height position information about the bucket (13) for excavation work. In this way, the ride control device or the automatic transmission control device can be appropriately controlled regardless of the preference or habit of the operator.

Abstract: A cooling fan control unit, in response to an operation performed at the rotation direction selector switch to select a reverse rotation setting while the cooling fan is rotating forward, lowers a relief pressure setting at the variable relief valve to a predetermined lower limit value over a predetermined length of time, and once the discharge pressure at the hydraulic pump detected by the pressure sensor is lowered to a predetermined switch-over pressure, executes control so as to switch the direction of flow of pressure oil to the hydraulic motor to the reverse direction by switching the direction switching valve and raises the relief pressure setting at the variable relief valve to a reverse rotation pressure setting, at which the hydraulic motor rotates in the reverse direction, over a predetermined length of time.

Abstract: An engine control device for a work vehicle decides that an idling stop condition is established when the front device is in the unengaged slate, the steering device is in the engaged state, the accelerator pedal is in the non-operation state, either the transmission is in the neutral state or the parking brake device is in the engaged state or the transmission is in the neutral state and also the parking brake device is in the engaged state, and the service brake device is in the unengaged state, and stops an engine when it is decided that it passes the predetermined length of time since it was decided that the idling stop condition was established.

Abstract: A clutch control device for a work vehicle includes a determination unit that determines as to whether or not a clutch cutoff condition has been established based upon whether or not the accelerator pedal is being operated, as determined by the accelerator pedal operation determination unit, the vehicle speed of the work vehicle detected by the vehicle speed detection unit and the braking force of the work vehicle detected by the braking force detection unit; and a clutch control unit that controls engagement/release of a clutch so as to release the clutch when the determination unit determines that the clutch cutoff condition has been established.

Abstract: A working vehicle motor control device includes: a rotational speed control device that controls a motor rotational speed in accordance with an operation amount of an accelerator pedal; a travel drive device that transmits rotation of the motor to wheels through a torque converter and a transmission; a speed ratio detection device that detects a speed ratio of an input shaft and an output shaft of the torque converter; and a speed restriction device that restricts a maximum rotational speed of the motor in accordance with a speed ratio detected by the speed ratio detection device. In the working vehicle motor control device, the speed restriction device restricts the maximum rotational speed when a detected speed ratio is in an acceleration region of the motor rotational speed to less than the maximum rotational speed when a detected speed ratio is in a non-acceleration region.

Abstract: To provide a drive control system for a working vehicle, which can prevent engine stall with certainty even when a large load suddenly acts on a vehicle-mounted engine and which is also excellent in environment friendly performance. When a vehicle speed of a wheel loader (1) is determined to be not higher than a reference value (Yes) in step S4 and a forward/reverse command means (40) is determined to have been switchingly operated (Yes) in step S5, the routine advances to step S6 where an increment ?N of engine speed according to an engine load factor is determined. In step S7, the increment ?N of engine speed is then added to a target engine speed Na corresponding to a depression stroke of an accelerator pedal (38), the thus-determined Na=Na+?N is set as a new target engine speed Na, and a target engine speed command i1 is sent to an engine controller (37).

Abstract: A construction machine includes a condenser 24 for cooling refrigerant for an air conditioner; a fan 21 for cooling the condenser 24 by using forward cooling air produced during normal-rotation drive; other cooled objects such as a radiator 25 and the like disposed under the lee of the forward cooling air with respect to the condenser 24; a refrigerant pressure detector 27 for detecting the pressure of the refrigerant flowing in the condenser 24; and a controller 136 for executing reverse-rotation stop processing for returning the fan 21 to the normal-rotation drive when the pressure P of the air conditioner refrigerant detected by the refrigerant pressure detector 27 reaches a preset normal-rotation return pressure P1 during reverse-rotation drive of the fan 21. Thus, the lowering of the cooling effect of an air conditioner can be suppressed while reducing the burden of cleaning an engine room.