Interrelated power delivery controls – including engine control – Transmission control – Control by sensed ambient condition – pattern indicia,...
Reexamination Certificate
2000-11-20
2003-06-24
Lorence, Richard M. (Department: 3681)
Interrelated power delivery controls, including engine control
Transmission control
Control by sensed ambient condition, pattern indicia,...
C477S111000
Reexamination Certificate
active
06582340
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a loading operation vehicle which can properly set a drive mode at an operating time and a traveling time.
BACKGROUND OF THE INVENTION
Conventionally, in a loading operation vehicle provided with a plurality of hydraulic pumps, there has been known a technique of selecting a combination obtained by changing an output characteristic of an engine and a cut-off condition of a hydraulic pump step by step in accordance with a magnitude of an operation load so as to improve a specific fuel consumption, and this technique is shown, for example, in Japanese Patent Publication No. 7-103593.
FIG. 4
shows a control system diagram of a loading operation vehicle disclosed in the publication mentioned above, and a description will be given below of a prior art with reference to FIG.
4
.
An output of an engine
1
is transmitted to a torque converter
2
and a gear unit
3
, and the output transmitted to the gear unit
3
drives fixed capacity hydraulic pumps
4
and
5
.
An electronically controlled type governor
7
capable of selecting the output characteristic of the engine
1
step by step on the basis of the output signal of a governor controller
6
is attached to the engine
1
. The governor controller
6
controls the electronically controlled type governor
7
on the basis of a mode selecting signal from an operating switch
8
.
The hydraulic pumps
4
and
5
are connected to a bucket main operating valve
10
and a boom main operating valve
11
. These working machine operating valves
10
and
11
respectively drive a bucket cylinder
15
and a boom cylinder
14
in accordance with an operation of a bucket operation pilot valve
12
and a boom operation pilot valve
13
.
A main unload valve
16
is provided in a discharge side of the hydraulic pump
4
. A pilot unload valve
17
and an electromagnetically switched type pilot cut-off valve
18
are connected to a pilot side of the main unload valve
16
.
A discharge side circuit of the hydraulic pump
5
is connected to the,pilot side of the pilot unload valve
17
and is opened and closed due to a discharge pressure thereof. Further, the pilot cut-off valve
18
can freely open and close on the basis of an electric signal from a cut-off valve controller
19
.
When setting the operating switch
8
to a mode
1
, the governor controller
6
outputs a command to the cut-off valve controller
19
so as to close the pilot cut-off valve
18
. Accordingly, the main unload valve
16
is opened and closed only on the basis of the discharge pressure of the hydraulic pump
5
.
That is, when the discharge pressure of the hydraulic pump
5
is low, the pilot unload valve
17
is closed, the main unload valve
16
is closed and a discharge fluid of the hydraulic pumps
4
and
5
flows through the cylinders
14
and
15
. Further, when the discharge pressure of the hydraulic pump
5
is high, the main unload valve
16
is opened and the discharge fluid in the hydraulic pump
4
is unloaded.
Further, when setting the operating switch
8
to a mode
2
, the governor controller
6
outputs a signal to the electronically controlled type governor
7
so as to set the output characteristic of the engine
1
so that the output torque is lower with respect to the same rotational number. At this time, in order to open the pilot cut-off valve
18
at an excavating operation time, the main unload valve
16
is opened and the discharge fluid in the hydraulic pump
4
is unloaded.
Further, in the case of setting the operating switch
8
to a mode
3
, the output torque of the engine
1
at the same engine rotational number is further lowered and the pilot cut-off valve
18
is always opened in accordance with a signal from the cut-off valve controller
19
, whereby the discharge fluid of the hydraulic pump
4
is unloaded.
As mentioned above, in accordance with the conventional art, the specific fuel consumption at the operating time is reduced and operability is improved selectively by a combination between the output characteristic of the engine
1
and the cut-off condition of the hydraulic pump
4
in correspondence to the magnitude of the operation load.
However, there are the following problems in the prior art disclosed in Japanese Patent Publication No. 7-103593.
For example, in the case of an operation of throwing a subject mounted in a bucket
20
to a crusher (not shown) or the like provided apart therefrom, it is necessary that the loading operation vehicle travels far away, so that the travel operation occupies a large percentage of all of the operation. Accordingly, since an amount of fuel consumption required for traveling occupies a large percentage of all of the amount of fuel consumption for the operation, it is required to reduce the amount of fuel consumption for the travel operation.
Further, since an operating time for traveling is increased, it is required to improve a driving characteristic during a traveling time and to reduce noise.
On the contrary, the conventional art relates to the structure for effectively loading and excavating and does not solve the problem of reducing the specific fuel consumption during the traveling time. Accordingly, in the case of the operation in which the traveling time is long, there is a problem that the total specific fuel consumption is not improved so much.
Further, the conventional art does not solve the problems of improving the characteristic during the traveling time and reducing noise, and no countermeasure against the requirement mentioned above is applied.
SUMMARY OF THE INVENTION
The present invention is made by taking the problem mentioned above into consideration, and an object of the present invention is to provide a loading operation vehicle which can reduce a specific fuel consumption during a traveling time and improve operability including a driving characteristic.
In order to achieve the object mentioned above, in accordance with a first aspect of the present invention, there is provided a loading operation vehicle comprising:
output characteristic changing means for changing an output characteristic of an engine in a plurality of stages;
shift timing changing means for changing a shift timing of an automatic transmission in a plurality of stages;
working machine flow amount changing means for changing a working machine flow amount of a pressurized oil flowing through a working machine actuator in a plurality of stages;
mode setting means for combining the output characteristic of the engine, the shift timing of the automatic transmission and the set value of the working machine flow amount with each other so as to set a plurality of modes; and
mode selecting means for freely selecting from the modes.
In accordance with the first aspect, there are provided a plurality of modes obtained by changing the output characteristic of the engine, the shift timing of the automatic transmission and the working machine flow amount step by step and combining them, and an operator can freely select the modes.
Accordingly, it is possible to select the combination of the output characteristic of the engine, the shift timing and the working machine flow amount in correspondence to a magnitude of a load, a traveling speed and a working speed. That is, it is possible to increase a working amount and perform a heavy load operation, and in the case that the operation is not a very heavy load operation and the operation is not required to be rapidly performed, it is possible to reduce a specific fuel consumption.
For example, by selecting so that the output characteristic of the engine is a characteristic having a high torque and a high rotation in the case that the load is heavy and selecting in an inverse manner in the case of a low load, the operation can be performed at a proper engine output, so that a wasteful fuel consumption is reduced and a specific fuel consumption can be improved.
Further, by changing the shift timing of the automatic transmission, it is possible to reduce the specific fuel consumption not only at a time of excavat
Arie Nobuyuki
Morimoto Katsuyuki
Nozawa Yasuhiko
Komatsu Ltd.
Lorence Richard M.
Pang Roger
Sidley Austin Brown & Wood LLP
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