JP2604404Y2 - Engine overheat prevention system - Google Patents

Description

[Detailed description of the invention]

[0001]

INVENTION The present invention relates, on the engine oleate Bahito prevention system.

[0002]

BACKGROUND OF THE INVENTION Figure 6 shows the error <br/> Nji oleate Bahito prevention system example in a conventional hydraulic excavator, 1 engine, 20 is the governor drive motor of the engine 1, 21 governor drive motor 20 Fuel injection pump controlled by 2
Is a variable displacement hydraulic pump driven by the engine 1 ( hereinafter simply referred to as "hydraulic pump 2" ), 3a is a traveling hydraulic motor which is one of actuators, and 3b is a working machine.
Use hydraulic cylinders, 4a, respectively 4b hydraulic motor 3
a, the operation valves of the hydraulic cylinder 3b, 5a and 5b are the operation valves 3
a, 6a and 6b are pilot cylinders of the operation valve 3b, 7a and 7b are hydraulic motors 3a and pilot control valves of the hydraulic cylinder 3b, 8a and 8b are operation levers of pilot control valves 7a and 7b, and 9 is an engine. 1 is a cooling water temperature sensor, and 10 is an engine rotation sensor. Also,
11 is a displacement control cylinder for controlling the displacement control device 2a of the hydraulic pump 2, 12 is an absorption torque variable valve for supplying control pressure to the displacement control cylinder 11, and 12a is for controlling the absorption torque of the absorption torque variable valve 12 to be constant. Hydraulic pump 2
, 12b and 12c are solenoids and springs for changing a constant absorption torque, 13 is a control pressure source for supplying control pressure to the variable absorption torque valve 12, and 14 is a control pressure source. Reference numeral 13 denotes a relief valve for keeping the discharge pressure constant, 15 denotes a monitor, 16 denotes a pump controller, 17 denotes a governor controller, 18 denotes a fuel setting dial, and 19 denotes a warning light.

[0003] Next, a description will be given of the operation of the above Symbol configuration. Setting signal of the fuel setting dial 18 that drive the governor drive motor 20 via the governor controller 17. If, then governor drive <br/> movement of the fuel injection pump 21 via a lever and a link is set fuel injection amount of the engine 1, the hydraulic pump 2 is rotated by the engine 1. At the same time, the control pressure of the control pump 13 is controlled to be constant according to the discharge pressure of the hydraulic pump 2 acting on the pilot cylinder 12a so that the absorption torque becomes constant according to the absorption torque setting signal input from the pump controller 16. And supply it to the displacement control cylinder 11 of the hydraulic pump 2. Therefore, the hydraulic pump 2 discharges a hydraulic oil amount determined by a discharge capacity of the hydraulic pump 2 controlled according to a constant absorption torque setting signal and a rotation speed of the engine 1. The operation of the hydraulic motor 3a and the hydraulic cylinder 3b is well known and will not be described. When you are working by the engine 1 as above Symbol,
When the cooling water temperature sensor 9 detects the overheating of the engine 1, the warning lamp 19 of the monitor 15 is turned on by the detection signal, thereby the operator is sensitized knowledge overheating.

[0004]

[Devised SUMMARY However, in the above SL prior art, the engine 1 by the operator warning lamp 19
Be sensitive knowledge of overheating, for or did not know the appropriate action to prevent overheating, in the know even if the rental vehicle or the like for example will give priority to work, to continue work in the state in which the engine 1 is overheating In some cases, there is a problem that the engine 1 is seriously damaged.

[0005]

In order to solve the above problems, an engine overheating prevention system according to the present invention is provided.
Is a variable displacement hydraulic pump driven by the engine
And various oil units and vehicle bodies using this hydraulic pump as a hydraulic source
A hydraulic motor for traveling and cooling of the engine
A cooling water temperature sensor for detecting water temperature, and
The absorption torque of the hydraulic pump in multiple stages
Equipped with a controller that can be set freely across floors
In the hydraulic drive device, the detection value from the sensor is predetermined.
If the water temperature exceeds the set value, the engine torque curve
The absorption torque of the hydraulic pump matched by
Switch to high torque without lowering engine speed
The first step, the hydraulic pump is the smallest of multiple stages
Even if it changes to absorption torque, the detection value from the sensor is
Exceeding the set value of the excess water temperature that is higher than the set value by a predetermined amount
Lower the engine speed to low idle
Both hydraulic pumps are smaller than the minimum absorption torque
And switch to an absorption torque that allows the vehicle to slow down.
Having a second step in an operation program
It is characterized by having a la .

[0006]

[Operation and effect] In the first step, the absorption torque is reduced.
The engine speed is reduced even if switching to the low absorption torque
Absent. That is, as is apparent from FIG.
Each absorption torque (T
At each matching point of 1>T2> T3), the absorption torque becomes smaller
As the engine speed increases, the engine speed increases. Ie small absorption
Switching to lux reduces the engine load
This reduces engine heat and further
The gin rotation does not decrease, but rather rises, so it cools
Higher fan rotation speeds up the cooling effect
Round. In other words, engine overheat
Engine overheat prevention system that can prevent
You. In addition, the second step is the same as the first step
If the cooling water temperature exceeds the excess water temperature set value (that is,
(When there is a sign that engine overheating will worsen)
Immediately reduce engine speed to low idle. Follow
Engine load is completely reduced,
Heat can be completely reduced, and the cooling fan at that time
The engine cooling water is cooled by the rotation of. And the second
In two steps, reduce the absorption torque enough to allow the vehicle
The vehicle can be evacuated to a safe place,
Easily investigate and repair signs of gin overheating
Can be done .

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described below in detail with reference to FIGS .
Incidentally, in the prior art and common elements in FIG. 6 duplicates Description <br/> Description denoted by the same reference numerals will be omitted. In FIG. 1, detected by a cooling water temperature sensor 9
Coolant temperature t of the engine 1 that is to enter the pump controller 16 and the governor controller 17 via the monitor 15. When the cooling water temperature t exceeds the upper limit water temperature set value t2 (102 ° C.), this is notified to the operator by a warning light 19, the engine fuel injection amount is controlled by the governor controller 17, and the variable displacement hydraulic pump is controlled by the pump controller 16. 2 is controlled.

In FIG. 2, when the cooling water temperature t approaches a predetermined value with respect to the upper limit water temperature set value t2 (102 ° C.) and reaches the control water temperature set value t1 (100 ° C.), although not shown , the pump controller 16 controls the absorption torque. the second absorption torque set value their Re reduced first absorption torque <br/> 10% from the set value T1 until the
Switch to T2 . Here, as shown in FIG. 2, if the reduction amount is sufficient , the cooling water temperature t starts to decrease thereafter,
If the charge-minute cooling water temperature t is then also it continues to rise. still,
In the second absorption torque set value T2 be continued without stop the work. Cooling water temperature t is the upper limit water temperature set value t2 (102 ° C)
If between-control water temperature set value t1 (100 ℃), to continue the second absorption torque setting T2. If the cooling water temperature t falls below the control water temperature set value t1 ( 100 ° C.) , the first absorption torque set value
Return to T1 and continue working.

[0009] For reducing the amount of non-charging component, when the cooling water temperature t exceeds the pull <br/> continue can rise to an upper limit temperature set value t2 (102 ° C.), the number pump controller 16 than the reduction amount The operation is reduced to the third absorption torque set value T3 which is twice as large as the light load mode, and the operation is continued in the light load mode. If this low <br/> weight loss is not sufficient, the cooling water temperature t upper limit temperature set value t
2 (102 ° C), but the upper limit water temperature set value t2 (102
° C.) a predetermined amount higher excess water temperature set value t3 than (105 ° C.)
If it is less than 3, the operation is continued in the light load mode which is the third absorption torque set value T3 . Reducing the amount of too many cooling water temperature t is an upper limit temperature set value t2 (102 ℃) ~ control water temperature set value t1 (100 ° C.) below between the lever and the second absorption torque setting T2
Return to and continue working. Incidentally, it decreases to a value less than reduction amount is too many cooling water temperature t is controlled water temperature set value t1 (100 ° C.), and continues to work back to the first absorption torque set value T1.

[0010] Once the third absorption increases also <br/> cooling water temperature t in the torque setpoint state T3 is followed by the cooling water temperature t is exceeded water temperature set value t3 (105 ° C.) or higher, failure in the cooling system of the engine 1 because it is when a, Rutotomoni reduces the absorption torque by the pump controller 16 to the extent that the car body can creep by a hydraulic motor, the governor controller 17
Let set the engine 1 to the low idle by. And the <br/> car body is retracted to a safe place, take action, such as to investigate the cause of failure. In this case, the upper limit water temperature set value t2 (102 ° C)
Under the following conditions, the normal control system can be restored only after the fuel setting dial 18 is once returned to the low idle position.

[0011] Figure 3 is an absorption torque shows, shows the first to third absorbing torque set value T1 ~ T3 are each constant. Figure 4 shows the engine torque curve, A is injected at a torque curve that is set by the fuel setting dial 18, the preparative <br/> Rukukabu the first to third absorbing on A torque set value T1 ~
The work is performed by T3. Further, Rutoki such a third rise subsequently cooling water temperature t of the cooling water temperature t in absorption torque set value T3 is <br/> excess water temperature set value t3 (105 ° C.) or higher, the torque curve of the low idle indicated by B with lowering the set value of the injected fuel to, it is retractable to lowered <br/> vehicle body up to the fourth absorption torque set value T0 to a safe place.

[0012] Figure 5 shows a detail of the pump controller 16 and the governor controller 17 in FIG. 1, 22 control water temperature setter for setting a control water <br/> temperature setpoint t1 (100 ℃), 23
First comparator for comparing the cooling water temperature t to enter via the set value t1 (100 ° C.) and a monitor 15 which is set by the control water temperature setter 22, 24 the first absorption torque set value T at the work start
The first absorption torque setter for setting a 1, 25 a second absorption torque setter for setting a second absorption torque setting T2, which is reduced by about 10% than the first absorption preparative <br/> torque set value T1 , 26 the first switching circuit to close the circuit by a signal from the first comparator 23, 27 is the upper limit temperature setting device for setting an upper limit water temperature set value t2 (102 ℃), 28 is set at the upper limit temperature setter 27
Set value t2 (102 ° C.) and a second comparator for comparing the cooling water temperature t to enter via the monitor 15, light-load work when having a reduced several tens of percent than the second absorption torque set value T2 is 29 A third absorption torque setting device 30 for setting the third absorption torque set value T3 , a second switch circuit 30 for closing the circuit by a signal from the second comparator 28, and 31 an upper limit water temperature set value t2 (102
° C.) a predetermined amount not higher than the excess water temperature set value t3 set a (105 ° C.)
The excess water temperature setting device 32 is set by the excess water temperature setting device 31 .
Third comparator, 33 a car body oils comparing boss was set values t3 and (105 ° C.) and <br/> Ru coolant temperature t enter via the monitor 15
A fourth absorption torque setter 34 for setting a fourth absorption torque set value T0 low enough to allow the motor 3a to move slowly;
The low idle setting device for setting the low idle of the engine 1, 35 and the third switch circuit for switching the set value B of the third comparator 32 injected by the signal from the fuel setting dial 18 low idle setting device 34 to set value A by It is.

Next, the operation of FIG. 5 will be described. The cooling water temperature t from the cooling water temperature sensor 9 is input to the monitor 15 . Here, when the cooling water temperature t exceeds the upper limit water temperature set value t2 (102 ° C.) which is the overheat set value, the warning lamp 19 is turned on. Further , the cooling water temperature t is input to the first comparator 23 of the pump controller 16 via the monitor 15, and is compared with the control water temperature set value t1 (100 ° C.) from the control water temperature setting device 22,
If “t <t 1” , the first absorption torque setting unit 24 outputs the first absorption torque set value T 1 to the absorption torque variable valve 12 . Where is If "t ≧ t1" at the cooling water temperature t first switching circuit 26 by a signal from the first comparator 23 is closed is inputted to the second comparator 28, the upper limit temperature setter 2
It is compared with an upper limit temperature set value t2 (102 ° C.) from 7. So
Then , if “t ≦ t2” , the second absorption torque setting unit 2
5 second absorption torque set value T2 absorption torque variable valve 1
Output to 2 . Where there is, if the "t>t2", the second
The second switch circuit 30 is closed by a signal from the comparator 28. Accordingly, the cooling water temperature t is input to the third comparator 32 and compared with the excess water temperature set value t3 (105 ° C.) from the excess water temperature setting device 31 . Then, if "t <t3", the output from the third absorption torque setter 29 the third absorption torque set value T3 to absorption torque variable valve 12. Where there is, "t ≧ t3"
If outputs from the fourth absorption torque setting unit 33 and the fourth absorption preparative Le <br/> click set value T0 to absorption torque variable valve 12.

At the same time, the signal from the third comparator 32 is input to the third switch circuit 35 of the governor controller 17, cuts the injection fuel signal set by the injection fuel setting dial 18, and outputs the signal from the low idle setting device 34. An injection fuel signal is output to the governor drive motor 20 to output the engine 1
Is a low idle B. That is, there is a relation as shown in Table 1, between the cooling water temperature t and the absorption torque.

TABLE 1 Note that when comparing the cooling water temperature t and the absorption torque in the table above, was used an equal sign when setting absorption torque T2 and T0, not limited thereto, the present invention be used in any absorption torque set at Of course, it has nothing to do with the gist of this.

[0015]

[Effect of the invention] According to the above embodiment, the first effect is that when the cooling water temperature of the engine was YouToshi reached overheating, variable to match the engine torque curve line
The absorption torque points of the displacement hydraulic pumps, that have allowed transition to a predetermined absorption torque points of the plurality of stages set in advance.
By reducing the absorption torque This ensures to reduce the load which has been applied to the engine, the engine overheat can be prevented because This ensures it is possible to lower the cooling water temperature. Second
Of the effect, the state of the engine overheat is deteriorated applications
To be Rutoki reduces engine speed to low idle, by matching the absorption torque point at a predetermined position of the low idle speed of the engine torque curve line, it was applied to the engine to further reduce the absorption torque load Can reduce the cooling water temperature in a short time.

[Brief description of the drawings]

FIG. 1 is an overall control block diagram of an embodiment.

FIG. 2 is a cooling water temperature characteristic diagram of an embodiment.

[3] is an absorption torque diagram of the embodiment.

FIG. 4 is an engine torque curve of the embodiment.

FIG. 5 is a detailed control block diagram of the embodiment.

FIG. 6 is a conventional control block diagram.

[Explanation of symbols]

1: Engine, 2: variable displacement hydraulic pump, 3 a: hydraulic motor, 4a, 4b: operating valve, 5a, 5b, 6a, 6
b: pilot cylinder, 7a, 7b: pilot control valve, 8a, 8b: operation lever, 9: cooling water temperature sensor, 1
0: engine rotation sensor, 11: displacement control cylinder, 1
2: absorption torque variable valve, 13: control pressure source, 1 5: Monitor, 16: pump controller, 17: governor controller, 18: fuel setting dial, 19: alarm lamp 20:
Governor drive motor, 21: fuel injection pump, 22: control water temperature setter, 23: first comparator, 24: first absorption torque setter, 25: second absorption torque setter, 26: first switch circuit, 27 : Upper limit water temperature setting device, 28: second comparator,
29: third absorption torque setting device, 30: second switch circuit, 31: excess water temperature setting device, 32: third comparator, 33:
Fourth absorption torque setting device, 34: low idle setting device, 3
5: Third switch circuit.

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F02D 29/00-29/06 F04B 49/00-51/00

Claims (1)

(57) [Scope of request for utility model registration] 1. A variable capacitor driven Ri by the engine (1)
Type hydraulic pump (2) and this hydraulic pump (2)
Equipped with various oil units (3b) and a hydraulic motor (3a)
And detect the temperature (t) of cooling water for the engine (1)
A cooling water temperature sensor (9) is provided and
The absorption torque of the hydraulic pump (2) can be set in multiple stages according to the detected value
Controller that can be set variably over (T1>T2> T3)
In the hydraulic drive device provided with (16) , the sensor (9)
Detected value (t) exceeds the specified water temperature set value (t1, t2 (t1 <t2))
(T ≧ t1, t> t2), the engine torque curve (A)
The absorption torque (T1) of the hydraulic pump (2)
Reduce the engine speed to a small absorption torque (T2, T3).
The first step of switching quickly and the hydraulic pump (2)
Change to minimum absorption torque (T3) in several stages (T1>T2> T3)
Even if the detected value (t) from the sensor (9) is
Set the excess water temperature set value (t3) that is set a predetermined amount higher than (1, t2).
If it exceeds (t ≧ t3), set the engine speed to low idle
And reduce the hydraulic pump (2) to the minimum absorption torque.
(T3) smaller than the (T3)
The second step of switching to the absorption torque (T0)
An engine overheating prevention system , comprising: a controller (16, 17) for each engine.