U.S. patent application number 14/909834 was filed with the patent office on 2017-03-02 for working vehicle and working vehicle control method.
This patent application is currently assigned to KOMATSU LTD.. The applicant listed for this patent is KOMATSU LTD.. Invention is credited to Shinya ARIMATSU, Tomotaka IMAI, Mitsuhiko KAMADO.
Application Number | 20170058490 14/909834 |
Document ID | / |
Family ID | 55304264 |
Filed Date | 2017-03-02 |
United States Patent
Application |
20170058490 |
Kind Code |
A1 |
KAMADO; Mitsuhiko ; et
al. |
March 2, 2017 |
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.
Inventors: |
KAMADO; Mitsuhiko;
(Hirakata-shi, Osaka, JP) ; ARIMATSU; Shinya;
(Takatsuki-shi, Osaka, JP) ; IMAI; Tomotaka;
(Hiratsuka-shi, Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KOMATSU LTD. |
Tokyo |
|
JP |
|
|
Assignee: |
KOMATSU LTD.
Tokyo
JP
|
Family ID: |
55304264 |
Appl. No.: |
14/909834 |
Filed: |
September 1, 2015 |
PCT Filed: |
September 1, 2015 |
PCT NO: |
PCT/JP2015/074848 |
371 Date: |
February 3, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E02F 3/32 20130101; F01N
2610/02 20130101; F01N 2610/142 20130101; E02F 9/2075 20130101;
E02F 9/2296 20130101; Y02T 10/24 20130101; E02F 9/2235 20130101;
Y02A 50/2325 20180101; Y02A 50/20 20180101; F01N 3/2066 20130101;
Y02T 10/12 20130101; E02F 9/0883 20130101; F01N 2430/00 20130101;
E02F 9/0866 20130101; F01N 2900/1814 20130101 |
International
Class: |
E02F 9/22 20060101
E02F009/22; E02F 9/08 20060101 E02F009/08 |
Claims
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)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a U.S. National stage application of
International Application No. PCT/JP2015/074848, filed on Sep. 1,
2015.
BACKGROUND
[0002] The present invention relates to a working vehicle and a
working vehicle control method.
FIELD OF THE INVENTION
[0003] A working vehicle is provided with an engine, a hydraulic
pump which is driven using an engine, and a hydraulic actuator
which is driven using hydraulic fluid which is discharged from the
hydraulic pump. The hydraulic actuator is, for example, a hydraulic
cylinder and drives a work implement which has a boom, an arm, and
the like. In this type of working vehicle, the hydraulic pump is
controlled so that the absorption torque of the hydraulic pump does
not exceed the output torque of the engine.
[0004] At the same time, the working vehicle is provided with an
exhaust processing apparatus which cleans exhaust from the engine
using reducing agent. In this type of working vehicle, the reducing
agent is retained in a reducing agent tank, but there is a
possibility that processing of exhaust is not appropriately
performed when the retention amount of the reducing agent inside of
the reducing agent tank is reduced to low levels. For this reason,
control is performed so that the output of the engine is reduced
and absorption torque of the hydraulic pump is reduced when the
retention amount of the reducing agent is reduced to be lower than
a predetermined amount in, for example, a working vehicle in
Japanese Unexamined Patent Application Publication No. 2015-71973.
Due to this, it is possible to prompt an operator to replenish the
reducing agent.
SUMMARY
[0005] A hybrid working vehicle, which is provided with a power
generator motor which is driven using the engine and an electric
actuator which is driven using electrical power which is generated
using the power generator motor along with the hydraulic pump and
the hydraulic actuator, is being developed in recent years. For
example, a hybrid hydraulic excavator is provided with a hydraulic
cylinder for driving a work implement and an electric motor for
revolving a revolving body.
[0006] In this type of hybrid working vehicle, it is desirable to
as efficiently as possible secure operation of both hydraulic
equipment and electrical equipment in a case where control is
performed so that the output of the engine is reduced when the
retention amount of the reducing agent is reduced to low levels.
However, even when it is possible for operation of the electrical
equipment to be easily secured only by reducing the absorption
torque of the hydraulic pump as in the prior art, it is difficult
for operation of the hydraulic equipment to be secured with the
output of the engine mainly used for the electrical equipment.
[0007] An aspect of the present invention is to as efficiently as
possible secure operation of both hydraulic equipment and
electrical equipment in a hybrid working vehicle while reducing the
output of an engine when the retention amount of reducing agent is
reduced to low levels.
[0008] A working vehicle according to one aspect of the present
invention is provided with an engine, a hydraulic pump, a hydraulic
actuator, a power generator motor, an electric actuator, an exhaust
processing apparatus, a reducing agent tank, a retention amount
detecting section, an engine control section, and an actuator
control section. The hydraulic pump is driven using the engine. The
hydraulic actuator is driven using hydraulic fluid which is
discharged from the hydraulic pump. The power generator motor is
driven using the engine. The electric actuator is driven using
electrical power which is generated using the power generator
motor. The exhaust processing apparatus cleans exhaust from the
engine. The reducing agent tank retains reducing agent which is
supplied to the exhaust processing apparatus. The retention amount
detecting section detects the retention amount of the reducing
agent inside the reducing agent tank. The 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.
[0009] In the working vehicle according to this aspect, the output
of the engine is reduced and the output of the electric actuator is
restricted when the retention amount is equal to or less than the
first threshold. For this reason, it is possible for the output of
the engine which is distributed to the hydraulic pump to be secured
to be large compared to a case where the output of the electric
actuator is not restricted. Due to this, it is possible to
efficiently secure operation of both hydraulic equipment and
electrical equipment in a hybrid working vehicle when the retention
amount of the reducing agent is reduced to low levels.
[0010] It is desirable that the working vehicle be further provided
with an output calculating section, an absorption torque
determining section, and a pump control section. It is desirable
that the output calculating section calculates the output of the
power generator motor which is necessary for driving the electric
actuator when the retention amount is equal to or less than the
first threshold. It is desirable that the absorption torque
determining section determines the absorption torque of the
hydraulic pump based on the output of the engine which is reduced
and the output of the power generator motor which is necessary for
driving the electric actuator. It is desirable that the pump
control section controls the hydraulic pump using the absorption
torque which is determined.
[0011] In this case, the absorption torque of the hydraulic pump is
determined based on the output of the engine which is reduced and
the output of the power generator motor which is necessary for
driving the electric actuator when the retention amount is equal to
or less than the first threshold. Here, the output torque of the
hydraulic pump which is necessary for driving the hydraulic
actuator varies significantly according to the load which is
applied to the work implement. Accordingly, it is not easy for the
torque which is to be distributed to the hydraulic pump to be
accurately estimated during the output restriction control.
[0012] In contrast to this, it is possible to accurately estimate
the output of the power generator motor which is necessary for
driving the electric actuator compared to the output torque of the
hydraulic pump which is necessary for driving the hydraulic
actuator. Accordingly, it is possible to efficiently determine the
output of the power generator motor which is necessary for driving
the electric actuator and the absorption torque of the hydraulic
pump by first calculating the output of the power generator motor
which is necessary for driving the electric actuator and
determining the absorption torque of the hydraulic pump based on
the result of this calculation. Due to this, it is possible to as
efficiently as possible secure operation of both the hydraulic
equipment and the electrical equipment in the hybrid working
vehicle when the retention amount of the reducing agent is reduced
to low levels.
[0013] It is desirable that 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. In this case, it is possible to prompt an operator to
replenish the reducing agent.
[0014] It is desirable that the working vehicle be further provided
with an electrical power control apparatus which is electrically
connected with the power generator motor and the electric actuator.
It is desirable that the electric actuator control section stops
the electrical power control apparatus when the retention amount is
equal to or less than the second threshold and predetermined system
stop condition is satisfied. In this case, it is possible to prompt
an operator to replenish the reducing agent.
[0015] It is desirable that the system stop conditions include the
operation speed of the electric actuator being reduced to a
predetermined speed. In this case, it is possible for the
electrical power control apparatus to be stopped in a state where
the electric actuator stops or is close to stopping. Due to this,
it is possible to avoid the electrical power control apparatus
stopping during operation of the electric actuator.
[0016] It is desirable that the system stop conditions further
include a torque command value to the power generator motor being
zero. In this case, it is possible to avoid the electrical power
control apparatus from stopping during power generation using the
power generator motor. Due to this, it is possible to prevent
damage to the electrical power control apparatus due to electrical
power which is generated by the power generator motor after
stopping of the electrical power control apparatus.
[0017] It is desirable that the electric actuator control section
sets the torque command value for the electric actuator to zero
when the retention amount is equal to or less than the second
threshold. Due to this, it is possible to stop the electric
actuator.
[0018] It is desirable that the engine control section controls the
output of the engine with a first engine torque curve during normal
periods when the retention amount is larger than the first
threshold. It is desirable that 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. In this
case, it is possible to reduce the output of the engine during the
output restriction control by changing between engine torque
curves.
[0019] It is desirable that the electric actuator control section
reduces an upper limit for the output torque of the electric
actuator during the output restriction control. Due to this, it is
possible to reduce the output of the electric actuator during the
output restriction control.
[0020] It is desirable that the working vehicle be further provided
with a traveling body and a revolving body which is supported so
that revolving is possible with regard to the traveling body. It is
desirable that the electric actuator be an electric motor which
revolves the revolving body. In this case, a variation in the load
which is applied to the electric motor is small compared to the
load which is applied to the hydraulic actuator. For this reason,
it is possible to accurately calculate the output of the power
generator motor which is necessary for driving the electric
actuator.
[0021] A working vehicle control method according to another aspect
of the present invention is provided with the following steps. A
first step is determining a retention amount of reducing agent
inside a reducing agent tank. A second step is performing output
restriction control where a signal which reduces the output of an
engine is output when the retention amount is equal to or less than
a first threshold. A third step is outputting a signal for
restricting the output of an electric actuator during execution of
the output restriction control.
[0022] In the working vehicle control method according to this
aspect, the output of the engine is reduced and the output of the
electric actuator is restricted when the retention amount is equal
to or less than the first threshold. For this reason, it is
possible for the output of the engine which is distributed to the
hydraulic pump to be secured to be large compared to a case where
the output of the electric actuator is not limited. Due to this, it
is possible to efficiently secure operation of both hydraulic
equipment and electrical equipment in a hybrid working vehicle when
the retention amount of the reducing agent is reduced to low
levels.
[0023] It is desirable that the working vehicle control method be
further provided with the following steps. A fourth step is
calculating the output of a power generator motor which is
necessary for driving the electric actuator. A fifth step is
determining the absorption torque of a hydraulic pump based on the
output of the engine which is reduced and the output of the power
generator motor which is necessary for driving the electric
actuator. A sixth step is outputting a command signal which
indicates the absorption torque of the hydraulic pump which is
determined.
[0024] In this case, it is possible to efficiently determine the
output of the power generator motor which is necessary for driving
the electric actuator and the absorption torque of the hydraulic
pump by first calculating the output of the power generator motor
which is necessary for driving the electric actuator and
determining the absorption torque of the hydraulic pump based on
the result of this calculation. Due to this, it is possible to as
efficiently as possible secure operation of both the hydraulic
equipment and the electrical equipment in the hybrid working
vehicle when the retention amount of the reducing agent is reduced
to low levels.
[0025] It is desirable that the working vehicle control method be
further provided with the following steps. A seventh step is
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. An eighth step is outputting a
stop signal for an electric power control apparatus when the
operation speed of the electric actuator is reduced to a
predetermined speed and a torque command value for the power
generator motor is zero after outputting the stop command.
[0026] In this case, it is possible to avoid the electrical power
control apparatus being stopping during operation of the electric
actuator. In addition, it is possible to avoid the electrical power
control apparatus being stopped during power generation using the
power generator motor. Due to this, it is possible to prevent
damage to the electrical power control apparatus due to electrical
power which is generated by the power generator motor after
stopping of the electrical power control apparatus.
[0027] According to exemplary embodiments of the present invention,
it is possible to as efficiently as possible secure operation of
both the hydraulic equipment and the electrical equipment in the
hybrid working vehicle while reducing the output of the engine when
the retention amount of the reducing agent is reduced to low
levels.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 is a perspective diagram of a working vehicle
according to an exemplary embodiment.
[0029] FIG. 2 is a schematic diagram illustrating a configuration
of an electrical equipment system and a hydraulic equipment system
in the working vehicle.
[0030] FIG. 3 is a schematic diagram illustrating a configuration
of an exhaust processing system in the working vehicle.
[0031] FIG. 4 is a schematic diagram illustrating a configuration
of a control system in the working vehicle.
[0032] FIG. 5 is a diagram illustrating one example of an engine
torque curve.
[0033] FIG. 6 is a diagram illustrating one example of a pump
absorption torque line during multiple operations.
[0034] FIG. 7 is a flow chart illustrating processes in output
restriction control.
[0035] FIG. 8 is a diagram illustrating one example of a derated
engine torque curve in output restriction control.
[0036] FIG. 9 is a diagram illustrating distribution of engine
output torque according to the exemplary embodiment and a
comparative example.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0037] A working vehicle according to an exemplary embodiment will
be described below with reference to the diagrams. FIG. 1 is a
perspective diagram of a working vehicle 100 according to the
exemplary embodiment. In the present exemplary embodiment, the
working vehicle 100 is a hydraulic excavator. The working vehicle
100 has a vehicle body 1 and a work implement 4.
[0038] The vehicle body 1 has a traveling body 2 and a revolving
body 3. The traveling body 2 has a pair of traveling apparatuses 2a
and 2b. Each of the traveling apparatuses 2a and 2b have crawler
tracks 2d and 2e. The working vehicle 100 travels due to the
traveling apparatuses 2a and 2b driving the crawler tracks 2d and
2e.
[0039] The revolving body 3 is mounted on the traveling body 2. The
revolving body 3 is provided so that revolving is possible with
regard to the traveling body 2. The revolving body 3 is revolved
due to being driven by a revolving motor 32 (refer to FIG. 2) which
will be described later. A driving cab 5 is provided in the
revolving body 3. The revolving body 3 has an engine chamber 20.
The engine chamber 20 is arranged behind the driving cab 5. The
engine chamber 20 accommodates equipment, such as an engine 21 and
a hydraulic pump 25 which will be described later.
[0040] The work implement 4 is attached to the revolving body 3.
The work implement 4 has a boom 7, an arm 8, a working attachment
9, a boom cylinder 10, an arm cylinder 11, and an attachment
cylinder 12. A base end portion of the boom 7 is joined to the
revolving body 3 so that operation is possible. A front end portion
of the boom 7 is joined to a base end portion of the arm 8 so that
operation is possible. A front end portion of the arm 8 is joined
to the working attachment 9 so that operation is possible.
[0041] The boom cylinder 10, the arm cylinder 11, and the
attachment cylinder 12 are hydraulic cylinders which are driven
using hydraulic fluid which is discharged from the hydraulic pump
25 which will be described later. The boom cylinder 10 operates the
boom 7. The arm cylinder 11 operates the arm 8. The attachment
cylinder 12 operates the working attachment 9. The work implement 4
is driven by the cylinders 10 to 12 being driven. Here, the working
attachment 9 is a bucket in the present exemplary embodiment, but
may be another attachment such as a crusher or a breaker.
[0042] FIG. 2 is a schematic diagram illustrating a configuration
of an electrical equipment system and a hydraulic equipment system
in the working vehicle 100. The engine 21 is, for example, a diesel
engine. The output horsepower of the engine 21 is controlled by
adjusting the amount of fuel which is ejected into the inside of
the cylinders of the engine 21. This adjusting is performed by
controlling an electronic governor 23, which is installed in a fuel
ejection pump 22 of the engine 21, using command signals from a
controller 60. A variable speed control type of governor is
typically used as the governor 23, and the engine rotation speed
and the fuel ejection amount are adjusted according to the load so
that the engine rotation speed is the target rotation speed which
will be described later. That is, the governor 23 increases and
decreases the fuel ejection amount so that there is no longer any
difference between the target rotation speed and the actual engine
rotation speed.
[0043] The actual rotation speed of the engine 21 is detected using
an engine rotation speed detecting section 24. The engine rotation
speed which is detected using the engine rotation speed detecting
section 24 is input to the controller 60 as a detection signal. The
output of the engine 21 is distributed between the hydraulic
equipment system and the electrical equipment system and this
equipment is driven. The hydraulic equipment system will be
described below.
[0044] The working vehicle 100 has the hydraulic pump 25. The
hydraulic pump 25 is joined with the output shaft of the engine 21.
The hydraulic pump 25 is driven by the output shaft of the engine
21 being rotated. The hydraulic pump 25 is a variable capacity type
of hydraulic pump. The hydraulic pump 25 has a swash plate 26 and
the capacity of the hydraulic pump 25 is changed due to changes in
the tilting angle of the swash plate 26.
[0045] A pump control valve 27 is operated using command signals
which are input from the controller 60 and the hydraulic pump 25 is
controlled through a servo piston. The pump control valve 27
controls the tilting angle of the swash plate 26 so that the
product of the discharge pressure of the hydraulic pump 25 and the
capacity of the hydraulic pump 25 does not exceed the pump
absorption torque which corresponds to command values (command
current values) in the command signals which are input from the
controller 60 to the pump control valve 27.
[0046] Hydraulic fluid which is discharged from the hydraulic pump
25 is supplied to hydraulic actuators 10 to 14 via an operating
valve 28. In detail, hydraulic fluid is supplied to the boom
cylinder 10, the arm cylinder 11, the attachment cylinder 12, a
right travel motor 13, and a left travel motor 14. The boom 7, the
arm 8, and the working attachment 9 are moved by the boom cylinder
10, the arm cylinder 11, and the attachment cylinder 12 being
driven. In addition, the traveling apparatuses 2a and 2b are moved
and the vehicle travels due to the right travel motor 13 and the
left travel motor 14 being driven.
[0047] The discharge pressure of the hydraulic pump 25 is detected
using a discharge pressure detecting section 29. The hydraulic
pressure of the hydraulic pump 25 which is detected using the
discharge pressure detecting section 29 is input to the controller
60 as a detection signal.
[0048] The operating valve 28 is a flow amount and direction
control valve which has a plurality of control valves which
correspond to each of the hydraulic actuators 10 to 14. The
operating valve 28 controls the flow amount of hydraulic fluid
which is supplied to each of the hydraulic actuators 10 to 14.
[0049] Next, the electrical equipment system will be described. The
working vehicle 100 has a power generator motor 31, a revolving
motor 32, a power storage apparatus 33, and an electrical power
control apparatus 34. The power generator motor 31 is joined with
the output shaft of the engine 21. The power generator motor 31
performs a power generating action and an electric moving action
depending on the circumstances.
[0050] Electrical power is stored in the power storage apparatus 33
due to the power generator motor 31 performing a power generating
action. The power storage apparatus 33 is, for example, a
capacitor. However, the power storage apparatus 33 is not limited
to being a capacitor and may be another type of power storage
apparatus. The power storage apparatus 33 supplies electrical power
to the revolving motor 32. The power storage apparatus 33 supplies
electrical power to the power generator motor 31 when the power
generator motor 31 performs an electric moving action.
[0051] The power generator motor 31 performs an electric moving
action when the output of the engine 21 is insufficient. The power
generator motor 31 is driven by electrical power being supplied
from the power storage apparatus 33 and the engine 21 is assisted
by this.
[0052] The revolving motor 32 is an electric motor which is driven
by electrical power being supplied from the power storage apparatus
33 or the power generator motor 31. The revolving motor 32 revolves
the revolving body 3 described above by being driven using
electrical power from the power storage apparatus 33 or the power
generator motor 31. In addition, the revolving motor 32 carries out
a regenerative operation when the revolving body 3 is decelerating.
That is, the revolving motor 32 generates electrical power by
regenerating the deceleration energy of the revolving body 3 and
supplies the electrical power which is generated to the power
storage apparatus 33.
[0053] A motor rotation detecting section 35 which detects the
rotation speed of the revolving motor 32 is provided in the
revolving motor 32. The rotation speed of the revolving motor 32
which is detected using the motor rotation detecting section 35 is
input to the controller 60.
[0054] The electrical power control apparatus 34 is electrically
connected to the power generator motor 31, the revolving motor 32,
and the power storage apparatus 33. The electrical power control
apparatus 34 controls electrical power which is supplied to the
power generator motor 31, the revolving motor 32, and the power
storage apparatus 33. The electrical power control apparatus 34 has
a first inverter 36, a second inverter 37, and a booster 38.
[0055] The first inverter 36 is connected with the power generator
motor 31. The second inverter 37 is connected with the first
inverter 36 and the revolving motor 32 is connected with the second
inverter 37. The booster 38 is connected between the first inverter
36 and the second inverter 37. The booster 38 is connected with the
power storage apparatus 33 via a contactor 39.
[0056] The contactor 39 is in a conducting state during normal
periods due to an electrical circuit between the power storage
apparatus 33 and the booster 38 being closed. The contactor 39 puts
the state into a cutoff state by opening the electrical circuit
according to a command from the controller 60 during periods with
abnormalities.
[0057] The first inverter 36 converts alternating current
electrical power which is generated using the power generator motor
31 to direct current electrical power when electrical power which
is generated using the power generator motor 31 is being charged
into the power storage apparatus 33. The first inverter 36 converts
direct current electrical power which is stored in the power
storage apparatus 33 to alternating current electrical power when
electrical power is being supplied from the power storage apparatus
33 to the power generator motor 31.
[0058] The second inverter 37 converts alternating current
electrical power which is generated using the revolving motor 32 to
direct current electrical power when electrical power which is
generated using the revolving motor 32 is being charged into the
power storage apparatus 33. The second inverter 37 converts direct
current electrical power which is stored in the power storage
apparatus 33 to alternating current electrical power when
electrical power is being supplied from the power storage apparatus
33 to the revolving motor 32.
[0059] The booster 38 controls the electrical power output from the
booster 38 due to being controlled by the controller 60. The
booster 38 boosts the voltage of the electrical power which is
supplied from the power storage apparatus 33 to the power generator
motor 31 via the first inverter 36 when the power generator motor
31 is carrying out an electric moving action. The booster 38 boosts
the voltage of the electrical power which is supplied from the
power storage apparatus 33 to the revolving motor 32 via the second
inverter 37 when the revolving motor 32 is being driven. In
addition, the booster 38 lowers the voltage which is supplied to
the power storage apparatus 33 when electrical power which is
generated using the power generator motor 31 or the revolving motor
32 is being charged into the power storage apparatus 33.
[0060] A voltage detecting section 41 is provided between the
booster 38 and the first and second inverters 36, 37. The voltage
detecting section 41 detects the size of the voltage which is
boosted by the booster 38. The voltage which is detected using the
voltage detecting section 41 is input to the controller 60.
[0061] A current detecting section 42 is provided in the second
inverter 37. The current detecting section 42 detects the current
which is input into the second inverter 37. The current, which is
input to the second inverter 37 and which is detected using the
current detecting section 42, is input to the controller 60.
[0062] A power storage voltage detecting section 43 is provided in
the power storage apparatus 33. The power storage voltage detecting
section 43 detects the voltage of the electrical power which is
stored in the power storage apparatus 33. The voltage of the
electrical power, which is stored in the power storage apparatus 33
and which is detected using the power storage voltage detecting
section 43, is input to the controller 60. The controller 60
monitors the amount of charging of the power storage apparatus 33
from the voltage of the electrical power which is stored in the
power storage apparatus 33,
[0063] The working vehicle 100 has a work implement operating
section 15 as shown in FIG. 2. The work implement operating section
15 is operated by an operator to move the work implement 4. The
work implement operating section 15 includes, for example, an
operating lever. The operating amount of the work implement
operating section 15 is input to the controller 60. In detail, the
operating amount of the work implement operating section 15 for
operating the boom 7 (referred to below as "boom operating
amount"), the operating amount of the work implement operating
section 15 for operating the arm 8 (referred to below as "arm
operating amount"), and the operating amount of the work implement
operating section 15 for operating the working attachment 9
(referred to below as "attachment operating amount") are input to
the controller 60.
[0064] The operating valve 28 described above is controlled
according to the operating amount of the work implement operating
section 15. The operating valve 28 modifies the area which is open
in the control valves which correspond to each of the hydraulic
cylinders 10 to 12 of the work implement 4 according to the
operating amount of the work implement operating section 15. As a
result, each of the hydraulic cylinders 10 to 12 are moved at
speeds according to the operating amount of the work implement
operating section 15.
[0065] The working vehicle 100 has a travel operating section 16.
The travel operating section 16 is operated by an operator to move
the right travel motor 13 and the left travel motor 14. The travel
operating section 16 includes, for example, an operating lever or
an operating pedal. Either of the right travel motor 13 or the left
travel motor 14 is driven according to the operating direction of
the travel operating section 16. The operating amount of the travel
operating section 16 is input to the controller 60. In detail, the
operating amount of the travel operating section 16 for operating
the right travel motor 13 (referred to below as "right travel
operating amount") and the operating amount of the travel operating
section 16 for operating the left travel motor 14 (referred to
below as "left travel operating amount") are input to the
controller 60.
[0066] The operating valve 28 modifies the area which is open in
the control valves which correspond to the right and left travel
motors 13 and 14 according to the operating amount of the travel
operating section 16. Due to this, the right and left travel motors
13 and 14 are moved at speeds according to the operating amount of
the travel operating section 16.
[0067] For example, a pilot pressure according to the operating
amount of the work implement operating section 15 and the operating
amount of the travel operating section 16 may be applied to a pilot
port of the operating valve 28. Due to this, the area which is open
in each of the control valves in the operating valve 28 are
modified according to the respective operating amounts.
Alternatively, the operating valve 28 may be electrically
controlled using the controller 60. In this case, the controller 60
inputs a command signal according to the operating amount of the
work implement operating section 15 and the operating amount of the
travel operating section 16 to the operating valve 28.
[0068] The working vehicle 100 has a revolving operating section
17. The revolving operating section 17 is operated by an operator
to move the revolving motor 32. The revolving operating section 17
includes, for example, an operating lever. The rotation direction
of the revolving motor 32 is switched according to the operating
direction of the revolving operating section 17. The operating
amount of the revolving operating section 17 is input to the
controller 60. The controller 60 controls electrical power which is
supplied to the revolving motor 32 according to the operating
amount of the revolving operating section 17. Due to this, the
revolving body 3 revolves at a speed according to the operating
amount of the revolving operating section 17.
[0069] The working vehicle 100 has a display apparatus 18. The
display apparatus 18 displays information on the working vehicle
100, such as the engine rotation speed. The working vehicle 100 has
an input apparatus 19. The input apparatus 19 is an apparatus for
inputting various types of settings for the working vehicle 100,
such as setting the working mode which will be described later.
Here, the display apparatus 18 and the input apparatus 19 may be
provided to be integrated using a touch panel type of monitor
apparatus.
[0070] Next, an exhaust processing system of the working vehicle
100 will be described. FIG. 3 is a schematic diagram illustrating a
configuration of the exhaust processing system in the working
vehicle 100. The working vehicle 100 has a first exhaust processing
apparatus 45 and a second exhaust processing apparatus 46 as shown
in FIG. 3. The first exhaust processing apparatus 45 is, for
example, a diesel particulate filtering apparatus. The first
exhaust processing apparatus 45 is connected with the engine 21 and
cleans particulate matter (PM) in the exhaust.
[0071] The second exhaust processing apparatus 46 is connected with
the first exhaust processing apparatus 45 via a mixing pipe 47. The
second exhaust processing apparatus 46 is, for example, a selective
catalytic reduction apparatus. The second exhaust processing
apparatus 46 cleans nitrogen oxides (NOx) in the exhaust with a
catalyst using a reducing agent, such as urea water. The exhaust
which is cleaned using the first exhaust processing apparatus 45
and the second exhaust processing apparatus 46 is released to the
outside of the working vehicle 100 via an exhaust pipe 48 which is
shown in FIG. 1.
[0072] A reducing agent injector 49 is attached in the mixing pipe
47. The reducing agent injector 49 ejects reducing agent inside the
mixing pipe 47. The reducing agent injector 49 is connected with a
reducing agent pump 51 and a reducing agent tank 52 via a reducing
agent hose 50. The reducing agent tank 52 retains reducing agent.
The reducing agent pump 51 draws reducing agent from the reducing
agent tank 52 and sends the reducing agent to the reducing agent
injector 49.
[0073] A retention amount detecting section 53 is provided in the
reducing agent tank 52. The retention amount detecting section 53
detects the retention amount of reducing agent inside the reducing
agent tank 52. The retention amount detecting section 53 inputs the
retention amount of reducing agent which is detected to the
controller 60.
[0074] Next, controlling which is executed using the controller 60
will be described. FIG. 4 is a schematic diagram illustrating a
configuration of the control system in the working vehicle 100. The
controller 60 is realized using a computer which has a memory
section 62, such as a RAM and a ROM, and a computing section 61,
such as a central processing unit (CPU) as shown in FIG. 4. The
controller 60 carries out programs to control the engine 21, the
hydraulic equipment system, and the electrical equipment system.
The controller 60 may be realized using a plurality of computers.
The controller 60 has an engine control section 63, a pump control
section 64, and an electric actuator control section 65 as shown in
FIG. 4.
[0075] The engine control section 63 performs control of the engine
21 based on engine torque curves P1 and E1 which are shown in FIG.
5. The engine torque curves P1 and E1 express upper value limits
for torque which it is possible for the engine 21 to output
according to the rotation speed. That is, the engine torque curves
P1 and E1 stipulate the relationship between the engine rotation
speed and the upper limit values for the output torque for the
engine 21. The engine torque curves P1 and E1 are stored in the
memory section 62.
[0076] The engine control section 63 determines the target rotation
speed for the engine 21 from the operating amount of the work
implement operating section 15, the operating amount of the travel
operating section 16, and the operating amount of the revolving
operating section 17. The operating amount of the work implement
operating section 15 is the total of the boom operating amount, the
arm operating amount, and the attachment operating amount described
above. The operating amount of the travel operating section 16 is
the total of the left travel operating amount and the right travel
operating amount. The engine control section 63 determines the
target rotation speed for the engine 21 according to, for example,
the total of the operating amount of the work implement operating
section 15, the operating amount of the travel operating section
16, and the operating amount of the revolving operating section 17.
The governor 23 controls the output of the engine 21 so that the
actual rotation speed of the engine 21 is the target rotation speed
while the output torque of the engine 21 does not exceed the engine
torque curves.
[0077] In FIG. 5, P1 indicates a first engine torque curve. The
first engine torque curve P1 is equivalent to the rating of the
engine 21 and the maximum power output. The first engine torque
curve P1 has a maximum torque point Pt and a rating point Pp. The
output torque of the engine 21 is at its maximum at the maximum
torque point Pt in the first engine torque curve P1. In addition,
the output horsepower of the engine 21 is at its maximum at the
rating point Pp in the first engine torque curve Pl.
[0078] The output torque of the engine 21 increases according to
increases in the engine rotation speed in the first engine torque
curve P1 over a range from where the engine rotation speed is a low
idle rotation speed NLi to where the engine rotation speed is an
engine rotation speed Nt at the maximum torque point Pt. The output
torque of the engine 21 falls according to increases in the engine
rotation speed over a range from where the engine rotation speed is
Nt to where the engine rotation speed is an engine rotation speed
Np at the rating point Pp.
[0079] A regulation line Rm, where the output torque of the engine
21 suddenly falls due to increases in the engine rotation speed, is
stipulated over a range where the rating point Pp is exceeded in
the first engine torque curve P1. The regulation line Rm is a line
which joins the rating point Pp and a maximum engine rotation speed
NHi in a state where there is no load.
[0080] The engine control section 63 selects the engine torque
curve according to the working mode which is set. The working mode
is set due to an operator manipulating the input apparatus 19.
There are a P mode and an E mode as the working modes.
[0081] The P mode is a working mode where the output torque of the
engine 21 is large and which is excellent for workability. The
first engine torque curve P1 which is shown in FIG. 5 is selected
in the P mode. The E mode is a working mode where the output torque
of the engine 21 is smaller than in the P mode and which is
excellent for fuel consumption. The second engine torque curve E1
which is shown in FIG. 5 is selected in the E mode. The output
torque of the engine 21 is smaller in the second engine torque
curve E1 than in the first engine torque curve P1. Here, it may be
possible to select a plurality of E modes where the output torque
of the engine 21 is reduced in stages.
[0082] The pump control section 64 controls the upper limit for the
absorption torque of the hydraulic pump 25 based on a pump
absorption torque line which is expressed by Lp1 and Le1 in FIG. 5.
Lp1 is a pump absorption torque line which corresponds to the first
engine torque curve P1. Le1 is a pump absorption torque line which
corresponds to the second engine torque curve E1. The pump
absorption torque lines Lp1 and Le1 stipulate the relationship with
the upper limit for the absorption torque of the hydraulic pump 25
which corresponds to the engine rotation speed. The pump absorption
torque lines Lp1 and Le1 are stored in the memory section 62.
[0083] The pump control section 64 controls the capacity of the
hydraulic pump 25 in the P mode so that the upper limit for the
engine output torque and the upper limit for the absorption torque
of the hydraulic pump 25 match at a matching point Mp1 with a
target rotation speed N1 for the engine 21. In the same manner, the
pump control section 64 controls the capacity of the hydraulic pump
25 in the E mode so that the upper limit for the engine output
torque and the upper limit for the absorption torque of the
hydraulic pump 25 match at a matching point Me1 with the target
rotation speed Ni for the engine 21.
[0084] Here, the pump absorption torque lines Lp1 and Le1 which are
shown in FIG. 5 indicate pump absorption torque lines where the
electric actuators such as the revolving motor 32 and the power
generator motor 31 are not used and only the hydraulic actuators
are used.
[0085] The electric actuator control section 65 controls the
revolving motor 32 and the power generator motor 31 by controlling
the electrical power control apparatus 34. The electric actuator
control section 65 controls the revolving motor 32 based on the
operating amount of the revolving operating section 17. The
electric actuator control section 65 controls the power generator
motor 31 based on the actual engine rotation speed, the target
rotation speed, the voltage of the power storage apparatus 33, and
the like.
[0086] For example, when the electric actuator control section 65
ascertains that the output of the engine 21 is insufficient based
on the actual engine rotation speed, the target rotation speed, the
voltage of the power storage apparatus 33, and the like, the engine
21 is assisted by an electric moving action being carried out by
the power generator motor 31. In addition, when the electric
actuator control section 65 ascertains that the output of the
engine 21 is not insufficient based on the actual engine rotation
speed, the target rotation speed, the voltage of the power storage
apparatus 33, and the like, the power storage apparatus 33 is
charged by a power generating action being carried out by the power
generator motor 31.
[0087] When the power generator motor 31 is controlled to perform a
power generating action, the electric actuator control section 65
determines a torque command value for the power generator motor 31
based on the voltage of the power storage apparatus 33. The
electric actuator control section 65 determines a torque command
value for the power generator motor 31 so that the voltage for
power storage is maintained within a predetermined range. The
electric actuator control section 65 controls the power generator
motor 31 so that the actual torque of the power generator motor 31
is the torque command value.
[0088] The electric actuator control section 65 determines the
target revolving speed from the operating amount of the revolving
operating section 17. For example, the electric actuator control
section 65 increases the target revolving speed according to
increases in the operating amount of the revolving operating
section 17. The electric actuator control section 65 determines a
torque command value for the revolving motor 32 to achieve the
target revolving speed from the actual revolving speed. The
electric actuator control section 65 controls the revolving motor
32 so that the torque of the revolving motor 32 is the torque
command value.
[0089] When the power generator motor 31 performs a power
generating action, a portion of the engine output torque is used to
drive the power generator motor 31. Accordingly, the controller 60
executes energy management where the engine output torque is
distributed to the hydraulic equipment system and the electrical
equipment system during multiple operations where there is
operating of the hydraulic equipment system and the electrical
equipment system at the same time. During energy management at
normal periods where output restriction control which will be
described later is not being executed, the upper limit for the
absorption torque of the hydraulic pump 25 is determined in
consideration of the engine output torque which is distributed to
drive the power generator motor 31.
[0090] In detail, the controller 60 has an output calculating
section 66 as shown in FIG. 4. The output calculating section 66
calculates the output of the power generator motor 31 which is
necessary for driving the revolving motor 32. For example, the
output calculating section 66 calculates the electrical power which
is needed for driving the revolving motor 32 from the output torque
of the revolving motor 32. Then, to obtain the electrical power
which is calculated, the output calculating section 66 determines
the amount of electrical power which is to be obtained from the
power storage apparatus 33 and the amount of electrical power from
a power generating action of the power generator motor 31. The
ratio of the amount of electrical power which is to be obtained
from the power storage apparatus 33 and the amount of electrical
power from a power generating action of the power generator motor
31 is determined according to the amount of electrical power which
is stored in the power storage apparatus 33. The output calculating
section 66 calculates the necessary output horsepower for the
engine 21 from the amount of electrical power from a power
generating action of the power generator motor 31 and determines an
engine output torque Thb (referred to below as "power generator
torque Thb") which is distributed to drive the power generator
motor 31 from the necessary output horsepower for the engine
21.
[0091] The controller 60 has an absorption torque determining
section 67 as shown in FIG. 4. The absorption torque determining
section 67 determines the absorption torque of the hydraulic pump
25 based on the power generator torque Thb. In detail, a value Tp2,
where the power generator torque Thb is subtracted from an upper
limit Tp1 for the pump absorption torque which is determined based
on the pump absorption torque line Lp1 described above, is
determined as the upper limit for the absorption torque of the
hydraulic pump 25 during multiple operations as shown in FIG.
6.
[0092] Here, Lp2 in FIG. 6 is a pump absorption torque line for
during multiple operations and stipulates the upper limit for the
absorption torque which is lower than the pump absorption torque
line Lp1 described above by the power generator torque Thb. The
pump absorption torque line Lp2 for during multiple operations is
modified according to increases and decreases in the power
generator torque Thb.
[0093] Energy management as described above is executed during
multiple operations where there is operating of the electrical
equipment system and the hydraulic equipment system at the same
time. Due to this, the total of the absorption torque of the
hydraulic pump 25 and the power generator torque is controlled to
not exceed the engine output torque.
[0094] In the working vehicle 100 according to the present
exemplary embodiment, the controller 60 executes the output
restriction control where the output of the engine 21 is restricted
according to the retention amount of the reducing agent inside the
reducing agent tank 52. The output restriction control will be
described below in detail.
[0095] FIG. 7 is a flow chart illustrating processes in the output
restriction control. As shown in FIG. 7, in step S1, a retention
amount A of the reducing agent inside the reducing agent tank 52 is
detected. In step S2, it is ascertained whether the retention
amount A is equal to or less than a threshold al. Here, the
retention amount A and the threshold al are, for example,
proportions of the remaining amount of the reducing agent with the
maximum retention amount in the reducing agent tank 52 as 100%.
However, the retention amount A and the threshold al are not
limited to being proportions of the remaining amount and may be the
volume of the reducing agent which remains. The same applies to
thresholds a2 to a4 which will be described later.
[0096] A first warning is issued in step S3 when the retention
amount A is equal to or less than the threshold al. The controller
60 displays the first warning on the display apparatus 18. The
first warning is, for example, a display, such as a message, which
notifies an operator that the retention amount is low.
[0097] Next, in step S4, it is ascertained whether the retention
amount A is equal to or less than the threshold a2. The threshold
a2 is smaller than the threshold al. A second warning is issued in
step S5 when the retention amount A is equal to or less than the
threshold a2. The controller 60 displays the second warning on the
display apparatus 18. The second warning is, for example, a display
such as a message which gives notice that output restriction will
be executed when the retention amount is further reduced.
[0098] Next, in step S6, it is ascertained whether the retention
amount A is equal to or less than the threshold a3. The threshold
a3 is smaller than the threshold a2. A first level of output
restrictions is executed in step S7 when the retention amount A is
equal to or less than the threshold a3.
[0099] The engine control section 63 reduces the engine output
torque in the first level of output restrictions. In detail, the
engine control section 63 outputs a command signal to the governor
23 so that the output of the engine 21 is controlled with a derated
engine torque curve D1 as shown in FIG. 8. The derated engine
torque curve DI stipulates the upper limit for output torque which
is lower than in the engine torque curves P1 and E1 during normal
periods when the retention amount A is larger than the threshold
a3. In other words, the derated engine torque curve DI stipulates
the upper limit for output torque which is lower than in the engine
torque curves P1 and E1 which are able to be selected by an
operator. The derated engine torque curve DI stipulates the upper
limit for output torque which is lower than in the engine torque
curves P1 and E1 during normal periods over a range of engine
rotation speeds which is at least equal to or more than the maximum
torque point Pt.
[0100] In addition, the electric actuator control section 65
outputs a command signal to the second inverter 37 in the first
level of output restrictions so that the output of the revolving
motor 32 is restricted. In detail, the electric actuator control
section 65 reduces the upper limit for the torque of the revolving
motor 32. For example, the electric actuator control section 65
reduces the upper limit for the torque command value for the
revolving motor 32. Due to this, the revolving speed is reduced to
be less than the target revolving speed according to the operating
amount of the revolving operating section 17.
[0101] The absorption torque determining section 67 determines the
absorption torque of the hydraulic pump 25 in the first level of
output restrictions based on the output of the engine 21 which is
reduced due to the first level of output restrictions and the power
generator torque Thb. In detail, the engine output torque is
reduced in the first level of output restrictions from an upper
limit value Te during normal periods to Te' as shown in FIG. 9. The
absorption torque determining section 67 determines the absorption
torque Tp' of the hydraulic pump 25 in the first level of output
restrictions by subtracting a power generator torque Thb' from the
engine output torque Te' which is reduced. The pump control section
64 outputs a command signal, which indicates the absorption torque
Tp' of the hydraulic pump 25 which is determined, to the pump
control valve 27. Due to this, the hydraulic pump 25 is controlled
using the absorption torque Tp' which is determined.
[0102] Here, the power generator torque Thb' in the first level of
output restrictions is calculated using the output calculating
section 66 in the same manner as the power generator torque Thb
during normal periods described above. Here, the power generator
torque Thb' in the first level of output restrictions is smaller
than the power generator torque Thb during normal periods since the
torque command value for the revolving motor 32 is reduced during
the first level of output restrictions as described above.
[0103] Next, in step S8, it is ascertained whether the retention
amount A is equal to or less than the threshold a4. The threshold
a4 is smaller than the threshold a3. A second level of output
restrictions is executed in step S9 when the retention amount A is
equal to or less than the threshold a4.
[0104] The engine control section 63 further reduces the engine
output torque in the second level of output restrictions compared
to the first level of output restrictions. In detail, the engine
control section 63 controls the output of the engine 21 with a
derated engine torque curve D2 as shown in FIG. 8. The derated
engine torque curve D2 stipulates the upper limit for output torque
which is lower than in the derated engine torque curve D1. In
addition, the derated engine torque curve D2 restricts the upper
limit for the engine rotation speed to Nd.
[0105] In addition, the electric actuator control section 65 stops
the revolving motor 32 in the second level of output restrictions.
In detail, the electric actuator control section 65 sets the torque
command value for the revolving motor 32 to zero.
[0106] Next, in step S10, the electric actuator control section 65
ascertains whether or not predetermined system stop conditions are
satisfied. When the predetermined system stop conditions are
satisfied, the electric actuator control section 65 outputs a stop
command to the electrical power control apparatus 34 in step S11.
Due to this, the entire system of the electrical equipment system
is stopped.
[0107] In detail, the system stop conditions are when both of the
following two conditions are satisfied. [0108] Condition 1--The
operation speed of the revolving motor 32 is reduced to be equal or
less than a predetermined speed. [0109] Condition 2--The torque
command value to the power generator motor 31 is zero.
[0110] Accordingly, the entire system of the electrical equipment
system is stopped when the operation speed of the revolving motor
32 is reduced to be equal or less than a predetermined speed and
power generating using the power generator motor 31 is stopped
after the output torque of the engine is reduced and there is a
command to stop the revolving motor 32 due to the second level of
output restrictions.
[0111] Next, in step S12, it is ascertained whether or not a
continuous time period T over which the retention amount A is equal
to or less than the threshold a4 is equal to or more than a
predetermined time period threshold t1. When the continuous time
period T is equal to or more than the predetermined time period
threshold t1, a third level of output restrictions is executed in
step S13.
[0112] The engine control section 63 controls the output of the
engine 21 in the third level of output restrictions with a derated
engine torque curve D3 as shown in FIG. 8. The engine rotation
speed is restricted to the low idle rotation speed NLi in the
derated engine torque curve D3.
[0113] In the working vehicle 100 according to the present
exemplary embodiment which is described above, the first level of
output restrictions is performed when the retention amount A of the
reducing agent is equal to or less than the threshold a3. The
absorption torque Tp' of the hydraulic pump 25 is determined in the
first level of output restrictions based on the engine output
torque Te' which is reduced and the power generator torque Thb' as
shown in FIG. 9. Here, the output torque of the hydraulic pump 25
which is necessary for driving the hydraulic actuators 10 to 14
varies significantly according to the load which is applied to the
work implement 4. Accordingly, it is not easy for the torque which
is to be distributed to the hydraulic pump 25 to be accurately
estimated during the output restriction control.
[0114] For example, in a comparative example which is shown in FIG.
9, output torque Thb'' of the power generator motor 31 is
determined by subtracting absorption torque Tp'' of the hydraulic
pump 25 from the engine output torque Te' which is reduced. In this
case, when the absorption torque of the hydraulic pump 25 is
actually Tp''' which is lower than the estimated value Tp'', the
engine output torque which is equivalent to the portion where
hatching is applied in FIG. 9 (Tp''-Tp''') is wasted since it is
not absorbed by the hydraulic pump 25 and it is not used in driving
the power generator motor 31.
[0115] In contrast to this, in the working vehicle 100 according to
the present exemplary embodiment, first, the power generator torque
Thb' is calculated and the absorption torque Tp' of the hydraulic
pump 25 is calculated based on the result of this calculation. It
is possible to accurately calculate the power generator torque Thb'
from the current value of the revolving motor 32 and the like. For
this reason, it is possible to efficiently determine the power
generator torque Thb' and the absorption torque Tp' of the
hydraulic pump 25. Due to this, it is possible to as efficiently as
possible secure operation of both the hydraulic equipment and the
electrical equipment in the hybrid working vehicle 100 when the
retention amount of the reducing agent is reduced to low
levels.
[0116] The second level of output restrictions is performed when
the retention amount A of the reducing agent is equal to or less
than the threshold a4. The engine output torque is further reduced
and the revolving motor 32 is stopped in the second level of output
restrictions. Due to this, it is possible to further prompt an
operator to replenish the reducing agent.
[0117] In addition, the electric actuator control section 65 stops
the electrical power control apparatus 34 when the retention amount
A of the reducing agent is equal to or less than the fourth
threshold a4 and the system stop conditions are satisfied. Due to
this, it is possible to further prompt an operator to replenish the
reducing agent since the entire electrical equipment system
stops.
[0118] The system stop conditions include the operation speed of
the revolving motor 32 being reduced to a predetermined speed. For
this reason, it is possible for the electrical power control
apparatus 34 to be stopped in a state where the revolving motor 32
stops or is close to stopping. Due to this, it is possible to avoid
the electrical power control apparatus 34 stopping during operation
of the revolving motor 32.
[0119] The system stop conditions include the torque command value
to the power generator motor 31 being zero. For this reason, it is
possible to avoid the electrical power control apparatus 34 from
stopping during power generation using the power generator motor
31. Due to this, it is possible to prevent damage to the electrical
power control apparatus 34 due to electrical power which is
generated by the power generator motor 31 after stopping of the
electrical power control apparatus 34.
[0120] One exemplary embodiment of the present invention is
described above but the present invention is not limited to the
exemplary embodiment described above and various modifications are
possible within a scope which does not depart from the gist of the
invention.
[0121] A hydraulic excavator is given as an example of the working
vehicle 100 in the exemplary embodiment described above, but the
present invention may be applied to other types of working
vehicles, such as a wheel loader. The electric actuator is not
limited to a revolving motor and may be a motor for travelling, a
motor for steering, or an electric actuator other than a motor.
[0122] The system stop conditions are not limited to the two
conditions described above and may be other conditions.
Alternatively, conditions other than the two conditions described
above may be added. Alternatively, one of either of the two
conditions described above may be omitted.
[0123] A portion of the processes in the output restriction control
may be omitted or modified. For example, the third level of output
restrictions may be omitted.
[0124] Restriction of the output of the revolving motor 32 may be
executed with the condition that the engine control section 63
executes a process where the engine output torque is reduced.
Restriction of the output of the revolving motor 32 may be executed
with the condition that the retention amount is equal to or less
than a threshold.
[0125] According to exemplary embodiments of the present invention,
it is possible to as efficiently as possible secure operation of
both hydraulic equipment and electrical equipment in a hybrid
working vehicle while reducing the output of an engine when the
retention amount of reducing agent is reduced to low levels.
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