JP2003020945A - Piston cooling device for diesel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piston cooling device for a diesel engine capable of reducing white smoke exhaust significantly. SOLUTION: The open/close valve controller 36 of the piston cooling device for a diesel engine stops the cooling system 30 by closing the open/close valve 35 when the lubrication oil temperature T detected by a temperature sensor 37 is not higher than a first temperature setting value. The controller 36 activates the cooling system 30 by opening the open/close valve 35 when the temperature T exceeds a second temperature setting value. Thus, by appropriately setting the first and second temperature the controller 36 can stop cooling the piston 102 when the lubricant oil temperature is low, in the other words, when the temperatures of a cylinder 101 and the piston 102 are low the combustion temperature in the cylinder 101 is low. This enables to encourage rise of the combustion temperature in the cylinder 101 and easy ignition of fuel complete combustion so that emission of unburned fuel and white smoke are reduced significantly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston cooling device for a diesel engine, more specifically, a cylinder and
The present invention relates to a diesel engine piston cooling device provided in a diesel engine including a piston that slides in the cylinder.

[0002]

BACKGROUND ART Conventionally, in an engine including a cylinder and a piston that slides in the cylinder, the piston is cooled in order to prevent an excessive temperature rise of the piston due to combustion and explosion of fuel in the cylinder. It is known to provide a mechanism for doing so. As such a piston cooling mechanism, a piston cooling nozzle that sprays a part of the lubricating oil of a lubricating system that lubricates sliding parts such as the crankshaft and camshaft of the engine to the inside of the piston is used. , This piston cooling nozzle promotes heat dissipation from the piston.

[0003]

By the way, for example, when the engine is started, or when the engine is operating in cold regions and cold seasons, the combustion temperature in the cylinder is hard to rise because the cylinder and piston are not warmed.
Unburned fuel may be discharged from the cylinder and white smoke may be discharged from the exhaust muffler. In this way, when the piston is cooled by the piston cooling nozzle described above during engine operation when the cylinder and piston are not warm, the cylinder and piston do not warm up easily, and the combustion temperature inside the cylinder becomes harder to rise. However, there is a problem that it becomes difficult to stop the emission of white smoke.

Particularly in a diesel engine, since only air is sucked into a cylinder and fuel is injected into high temperature air compressed by a piston, self ignition is performed.
When the combustion temperature in the cylinder is low, ignition and complete combustion of fuel are less likely to occur, and a large amount of unburned fuel is discharged,
There is a problem that white smoke is easily emitted. Further, in recent years, for example, in engines such as diesel engines, nitrogen oxides in exhaust gas of the engine, so-called NO
It is known to use an emulsion fuel in which a fuel and water are mixed in order to reduce harmful substances such as x, but the emulsion fuel has water and thus has poor ignitability. Further, when such an emulsion fuel having poor ignitability is used in an engine, there is a problem that the ignition and complete combustion of the fuel are less likely to occur and the emission of white smoke increases.

An object of the present invention is to provide a piston cooling device for a diesel engine, which can greatly reduce the emission of white smoke from the diesel engine.

[0006]

In order to achieve the above object, a piston cooling device for a diesel engine according to the present invention is provided in a diesel engine equipped with a cylinder and a piston sliding in the cylinder. A piston cooling device for a diesel engine, comprising piston cooling means for blowing a refrigerant to the piston to cool the piston, and control means for controlling the operation of the piston cooling means, wherein the control means is the In order to determine whether to start or stop the piston cooling means, a determining means for determining the state of the diesel engine, and a starting means for starting the piston cooling means based on a signal from this determining means are included. The determination means starts timing when the diesel engine is started and a predetermined time has elapsed. Then it is characterized in that outputs a predetermined signal to the activating means. Here, as the piston cooling means, one provided in advance in the diesel engine may be used, or one different from the one provided in the diesel engine may be used.

According to the present invention, the piston cooling means is started by the control means after a predetermined time has elapsed from the engine start. Therefore, when the engine is started when the cylinder and piston are normally cooled, the piston cooling means is started. As a result, the piston is not cooled and the temperature of the piston and the cylinder, that is, the combustion temperature in the cylinder can be increased. Therefore, ignition and complete combustion of the fuel easily occur in a short time after the engine is started, the amount of unburned fuel can be reduced, and the amount of white smoke can be significantly reduced. Also, if the predetermined time is set appropriately, after the combustion temperature in the cylinder has risen to a sufficient temperature, the control means can activate the piston cooling means to cool the piston, so the temperature of the piston rises excessively. Can be prevented and the durability of the engine is not impaired.

On the other hand, in order to achieve the above-mentioned object, the diesel engine piston cooling device of the present invention is a diesel engine piston cooling device provided in a diesel engine equipped with a cylinder and a piston sliding in the cylinder. A piston cooling means for blowing a refrigerant to the piston to cool the piston, a load detection means for detecting a load state of the diesel engine, and a control means for controlling the operation of the piston cooling means. The control means determines the state of the diesel engine to determine whether to start or stop the piston cooling means, and the piston cooling means is started based on a signal from the determination means. Of the piston cooling means based on the signal from the starting means and the determining means. The determination means outputs a predetermined signal to the stop means when the load detected by the load detection means is equal to or lower than a first load set value, and the load detection means is provided. When the load detected by the means exceeds the second load set value, a predetermined signal may be output to the starting means. Here, the first load setting value and the second load setting value may be the same value or different values. Further, the load detecting means for detecting the engine load may be one for detecting the amount of fuel injected / supplied into the cylinder of the engine, and the engine torque,
That is, the engine output may be detected,
In short, it is only necessary to detect an engine parameter that varies substantially proportionally according to the load state of the engine.

According to the present invention, the control means stops the piston cooling means when the engine load detected by the load detecting means is less than or equal to the first load set value, and when the engine load exceeds the second load set value. Since the piston cooling means is started, by appropriately setting the first load setting value and the second load setting value, when the engine load is low, that is, when the fuel supplied to the cylinder is small and the combustion temperature is low, The cooling of the piston by the piston cooling means can be stopped. As a result, it is possible to accelerate the rise of the combustion temperature in the cylinder, facilitate the ignition and complete combustion of the fuel, reduce the discharge of unburned fuel, and significantly reduce the discharge of white smoke. On the other hand, when the engine load is high, that is, when the amount of fuel injected / supplied into the cylinder is large and the combustion temperature is high, the piston cooling means can be activated to cool the piston, so the temperature of the piston rises excessively. Can be prevented and the durability of the engine is not impaired.

In the diesel engine piston cooling device of the present invention described above, it is desirable that the first load set value be set smaller than the second load set value.
For example, when the first load setting value and the second load setting value are substantially the same value, if the engine load fluctuates slightly within a range that exceeds the first load setting value (that is, the second load setting value) (so-called hunting). Occurs, the engine load becomes less than or equal to the first load setting value or exceeds the second load setting value, so that the control means repeatedly starts and stops the piston cooling means within a short time. Occurs. In the present invention, the first load setting value and the second load setting value are not the same value, and the first load setting value is set smaller than the second load setting value. Therefore, the first load setting value and the second load setting value are set. If the set value is appropriately set, for example, even when the engine load fluctuates finely in a range that exceeds the first load set value, the engine load rarely exceeds the second load set value in the fluctuation. From
The control means only stops the piston cooling means, and it is possible to solve the problem that the piston cooling means is repeatedly started and stopped in a short time.

Further, in order to achieve the above object, the piston cooling device for a diesel engine of the present invention is a piston cooling device for a diesel engine, which is provided in a diesel engine provided with a cylinder and a piston sliding in the cylinder. It is provided with a piston cooling means for blowing a refrigerant to the piston to cool the piston, a temperature detecting means for detecting the temperature of the diesel engine, and a control means for controlling the operation of the piston cooling means. The control means determines the state of the diesel engine in order to determine whether to start or stop the piston cooling means, and to start the piston cooling means based on a signal from this determination means. Start means to perform and stop of the piston cooling means based on the signal from the determination means The determining means outputs a predetermined signal to the stopping means when the temperature detected by the temperature detecting means is equal to or lower than a first temperature set value, and the determining means includes the stopping means. The detected temperature is the second
It may be characterized in that a predetermined signal is output to the starting means when the temperature setting value is exceeded. Here, the first temperature set value and the second temperature set value may be the same value or different values. Further, as the temperature of the engine, the temperature of the coolant of the engine, the temperature of the lubricating oil of the engine, or the like can be adopted.

According to the present invention, the control means stops the piston cooling means when the temperature of the engine detected by the temperature detecting means is equal to or lower than the first temperature set value, and exceeds the second temperature set value. Since the piston cooling means is started at the time, by appropriately setting the first temperature set value and the second temperature set value, when the engine temperature is low, that is, when the cylinder and piston temperatures are low and the combustion temperature in the cylinder is low. Moreover, the cooling of the piston by the piston cooling means can be stopped. As a result, the rise of the combustion temperature in the cylinder can be promoted, the ignition and complete combustion of the fuel can easily occur, the amount of unburned fuel can be reduced, and the amount of white smoke can be significantly reduced. On the other hand, when the engine temperature is high, that is, when the cylinder and piston temperatures are high and the combustion temperature in the cylinder is high, the control means can activate the piston cooling means to cool the piston. It can be prevented from rising and the durability of the engine will not be impaired. In addition, since the start / stop of the piston cooling means is controlled based on the engine temperature affected by the outside air temperature, the start / stop of the piston cooling means is controlled not only according to the engine state, but also according to the temperature, etc. Can be done. Therefore, even during engine operation in cold regions and cold seasons, the start / stop of the piston cooling means can be appropriately controlled.

In the diesel engine piston cooling device of the present invention described above, it is desirable that the first temperature set value be set smaller than the second temperature set value.
In this way, by setting the first temperature set value smaller than the second temperature set value, even if the engine temperature fluctuates finely in a range that exceeds the first temperature set value, for example, Since the engine temperature rarely exceeds the second temperature set value in
It is possible to solve the problem that only the piston cooling means is stopped and the piston cooling means is repeatedly started and stopped in a short time.

In any one of the diesel engine piston cooling devices of the present invention described above, the piston cooling means is an oil pump for pumping up the lubricating oil of the diesel engine, and the lubricating oil discharged from the oil pump is applied to the piston. A nozzle that sprays toward the nozzle, and an oil passage that guides the lubricating oil discharged from the oil pump to the nozzle, the stopping means shuts off the oil passage, and the starting means is It is desirable to open the oil passage. According to the present invention, the piston cooling means cools the piston by spraying the lubricating oil pressurized by the oil pump from the nozzle toward the piston, and the starting means and the stopping means connect the oil pump and the nozzle. Since the piston cooling means is started and stopped by opening and closing the oil passage to be connected, the starting means and the stopping means can be easily configured by using a valve or the like. Also, if you use the oil pump and piston cooling nozzle that the conventional engine lubrication system has as the oil pump and nozzle,
Since it is not necessary to separately provide the piston cooling means, cost reduction and space saving can be achieved.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a lubrication system 1 including a diesel engine piston cooling device according to a first embodiment of the present invention. Diesel engine
A plurality of (only one is shown in FIG. 1) cylinders 101,
Each cylinder 101 is provided with a piston 102 that slides in the cylinder 101, and only air is sucked into the cylinder 101, and fuel is injected into the high temperature air compressed by the piston 102 to self-ignite the crankshaft 103. It is an engine that is driven to rotate to generate power. Here, the diesel engine is an engine that uses a water emulsion fuel as a fuel to reduce the amount of NOx in the exhaust gas. The water emulsion fuel is a mixture of water, light oil and a surfactant, or water. And a mixture of heavy oil and a surfactant.

The lubrication system 1 is provided with an oil pan 11 containing a lubricating oil, and an oil pump 12 for sucking and discharging the lubricating oil from the oil pan 11. The discharge side of the oil pump 12 is bifurcated, and a lubrication system 20 that guides the lubricating oil to the lubrication required portion of the diesel engine to lubricate the lubrication required portion of the diesel engine and a piston of the diesel engine that is connected to the oil pump 12 are provided. 10
2 are respectively connected to a cooling system 30 that guides lubricating oil to the piston 102 to cool the piston 2. The piston cooling means of the present invention comprises an oil pan 11, an oil pump 12, and a cooling system 30. The lubricating oil pumped from the oil pan 11 by the oil pump 12 has a lubricating system 20 and a cooling system 3, respectively.
After being guided to the lubrication necessary portion and the piston 102 by 0, it is returned to the oil pan 11.

The lubricating system 20 includes an oil cooler 21 for cooling the lubricating oil discharged from the oil pump 12, an oil filter 22 for filtering the lubricating oil cooled by the oil cooler 21, and an oil filter 22 for filtering the lubricating oil. The main gallery 23 into which the lubricating oil flows, and the lubrication passage 24 that sequentially connects the oil pump 12, the oil cooler 21, the oil filter 22, and the main gallery 23.
It is configured to include and. In the lubrication system 20, the lubricating oil that has flowed into the main gallery 23 is supplied from the main gallery 23 to each lubrication necessary portion of the diesel engine to lubricate that portion. Here, the crankshaft 10 is used as the lubrication-needed part of the diesel engine.
3, a timing gear and a camshaft which are rotationally driven by the crankshaft 103, a supercharger 1 provided in a diesel engine for compressing intake air for supercharging
04, a fuel injection pump 1 for pressurizing the fuel in order to inject and supply the fuel into the cylinder 101 of the diesel engine
05 etc. are mentioned.

The cooling system 30 is connected to the main cooling passage 31 that guides the lubricating oil discharged from the oil pump 12 to the vicinity of the piston 102, and is connected to the main cooling passage 31 as well as the lubricating oil in the main cooling passage 31. Multiple (Fig. 1
A plurality of branch cooling passages 32 are respectively introduced to the piston 102 (only one is shown).
Here, as many branch cooling passages 32 as the number of pistons 102 are provided. Each branch cooling passage 32
As shown in FIG. 2, the tip of the branch cooling passage 32
A piston cooling nozzle 33 is provided for spraying the lubricating oil of No. 2 toward the inner surface 102A of the piston 102.

Returning to FIG. 1, in the middle of the main cooling passage 31, there is provided a regulator valve 34 and an opening / closing valve 35 arranged downstream of the regulator valve 34 as a stopping means and a starting means of the present invention. Has been.
The regulator valve 34 is a valve that shuts off the main cooling passage 31 when the discharge pressure of the oil pump 12 is lower than the set pressure, and the set pressure is, for example, 0.1 to 0.2 MPa. It is set. Thus, when the discharge pressure of the oil pump 12 is lower than the set pressure of the regulator valve 34, that is, when the rotation speed of the diesel engine is low and the temperature of the lubricating oil is high and the viscosity is low, the main cooling by the regulator valve 34 is performed. By blocking the use passage 31, the lubricating oil discharged from the oil pump 12 can be preferentially supplied to the lubrication system 20 (the lubrication passage 24).

Referring specifically to FIG. 3, the structure of the regulator valve 34 will be described in detail. The regulator valve 34 includes a substantially cylindrical main body 341 having an open bottom.
The main body 341 has an inlet 341A which is an opening on one end side.
And the main body 341 is formed in the middle of the main body 341 in the longitudinal direction.
1 has an outlet 341B that communicates the inside and the outside. The inlet 341A and the outlet 341B of the main body 341 are in communication with each other inside the main body 341, and the lubricating oil discharged from the oil pump 12 flows into the main body 341 from the inlet 341A to the outside from the outlet 341B, that is, the opening / closing valve 35. It is supposed to flow out to the side.

Inside the cylinder of the main body 341, the other end side (bottom side)
3 is provided, and a valve element 343 disposed on the right side of the compression spring 342 in FIG. 3 is provided. The compression spring 342 causes the valve element 343 to move along the longitudinal direction of the main body 341 toward the inlet 341A side. Is urged to. Here, the diameter of the inlet 341A of the main body 341 is smaller than the diameter of the cylindrical inner peripheral surface of the main body 341, and the inlet 341A and the main body 3 are
A step 341C is formed between the inner peripheral surface of the cylinder 41 and 41. The valve body 343 is urged toward the inlet 341A side by the compression spring 342 and its head is in contact with the step 341C.

In the regulator valve 34 having such a structure, the lubricating oil discharged from the oil pump 12 and flowing into the inside of the main body 341 from the inlet 341A reaches the head of the valve body 343 which is in contact with the step 341C.
The pressure due to the lubricating oil (the discharge pressure of the oil pump 12) is the spring pressure of the compression spring 342, that is, the regulator valve 34.
If the pressure is less than the set pressure of
Since it remains in contact with 1C, the lubricating oil is blocked by the valve body 343, and the main cooling passage 31 is blocked by the regulator valve 34. on the other hand,
When the pressure of the lubricating oil is higher than the set pressure of the regulator valve 34, the valve body 343 is pushed by the lubricating oil and its head is separated from the step 341C, so that a gap is created between the valve body 343 and the step 341C, and the lubrication is performed. Oil passes through this gap and exits 34
It comes to flow from 1B to the outside, that is, to the opening / closing valve 35 side.

The opening / closing valve 35 arranged on the downstream side of the regulator valve 34 is an on / off valve, and its opening / closing operation is controlled by the opening / closing valve controller 36. The control means of the present invention comprises an open / close valve 35 and an open / close valve controller 36. The open / close valve controller 36 controls the open / close valve 35 based on a temperature signal from a temperature sensor 37 as a temperature detecting means for detecting the temperature of the lubricating oil in the oil pan 11. Specifically, the opening / closing valve controller 36, as shown in FIG.
An input unit 36A to which a temperature signal from the input unit is input, an arithmetic processing unit 361 as a determination unit that determines the state of the diesel engine based on the signal from the input unit 36A to determine the opening / closing operation of the opening / closing valve 35, This arithmetic processing unit 3
A storage unit 362 that stores information necessary for the arithmetic processing performed at 61, and an output unit 36 that outputs a predetermined signal to the opening / closing valve 35 based on the arithmetic processing result at the arithmetic processing unit 361.
B and. In the present embodiment, the diesel engine piston cooling device includes an oil pan 11, an oil pump 12, and a cooling system 30 as piston cooling means, an opening / closing valve 35 and an opening / closing valve controller 36 as control means, and temperature detection. The temperature sensor 37 as a means is included. In this piston cooling device for a diesel engine, an oil pan 11, an oil pump 12, and the like, which the diesel engine has in advance,
The piston cooling means is configured by using the cooling system 30.

The cooling system 30 of the diesel engine lubrication system 1 does not cool the piston 102 when the temperature of the diesel engine, that is, the temperature of the lubricating oil accommodated in the oil pan 11 is low, and the lubrication is performed. The on-off valve controller 36 controls to cool the piston 102 when the oil temperature is high.

For such a cooling system 30, the arithmetic processing unit 361 of the opening / closing valve controller 36 operates the opening / closing valve 35 when the temperature of the lubricating oil contained in the oil pan 11 is equal to or lower than the first temperature set value. By closing it, the main cooling passage 31 is blocked so that the lubricating oil cannot be sprayed from the piston cooling nozzle 33.
The cooling of the piston 102 due to is stopped. On the other hand, the arithmetic processing unit 361 opens the open / close valve 35 when the temperature of the lubricating oil housed in the oil pan 11 exceeds the second temperature set value, whereby the main cooling passage 31 is opened.
To allow the lubricating oil to be sprayed from the piston cooling nozzle 33.
2 cooling is activated.

The above-mentioned first temperature set value and second temperature set value are stored in advance in the storage unit 362 of the on-off valve controller 36. The first and second temperature set values will be described in detail with reference to FIG.
The first and second temperature set values T2 are different from each other, and the first temperature set value T1 is set smaller than the second temperature set value T2. Here, the difference between the first temperature setting value T1 and the second temperature setting value T2 is preferably 5 ° C to 10 ° C. When the temperature of the lubricating oil detected by the temperature sensor 37 is equal to or lower than the first temperature set value T1, the arithmetic processing unit 36
1 outputs a signal to close the open / close valve 35, and when the second temperature set value T2 is exceeded, the arithmetic processing unit 361 outputs a signal to open the open / close valve 35 and exceeds the first temperature set value T1. When the temperature setting value is equal to or lower than the second temperature set value T2, the arithmetic processing unit 361 does not output a signal to maintain the current state of the opening / closing valve 35.

Next, the operation of this embodiment will be described based on the flowchart of FIG. When the diesel engine is started, the open / close valve controller 36 is started. The activated on-off valve controller 36 closes the on-off valve 35 by outputting a signal to close the on-off valve 35 to the on-off valve 35 in step S1. After this, step S
At 2, the temperature sensor 37 starts receiving a lubricating oil temperature signal indicating the temperature T of the lubricating oil in the oil pan 11. Then, in step S3, it is confirmed whether or not the lubricating oil temperature T is equal to or lower than the first temperature set value T1, and the lubricating oil temperature T is set to the first temperature set value T1.
When it is below, it progresses to step S4. On the other hand, when the lubricating oil temperature T exceeds the first temperature set value T1, the process proceeds to step S6.

In step S4, the opening / closing valve controller 36 closes the opening / closing valve 35, and the process proceeds to step S5. In this step S4, the on-off valve 3
If the current state of 5 (the state before the signal is output from the on-off valve controller 36) is closed, it remains closed, and if it is open, it is closed.
As a result, the main cooling passage 31 of the cooling system 30 is blocked, the lubricating oil is not sprayed from the piston cooling nozzle 33, the cooling of the piston 102 by the cooling system 30 is stopped, and the lubrication discharged from the oil pump 12 is stopped. The oil is preferentially supplied to the lubrication system 20 (lubrication passage 24). Therefore, when the lubricating oil temperature T is low,
That is, when the temperatures of the cylinder 101 and the piston 102 are low and the combustion temperature in the cylinder 101 is low, the increase in the combustion temperature in the cylinder 101 is promoted, the amount of unburned fuel is reduced, and the emission of white smoke is significantly reduced. Will be reduced.

In step S5, it is confirmed whether or not the temperature sensor 37 finishes detecting the lubricating oil temperature T. That is, it is confirmed whether or not the diesel engine is operating, and if the diesel engine is stopped, the on-off valve controller is also stopped, and the process ends. On the other hand, if the diesel engine continues to operate, the process returns to step 3 and the series of steps starting from step S3 described above is repeated many times until the diesel engine stops. In step 6, it is confirmed whether or not the lubricating oil temperature T exceeds the second temperature setting value T2. When the lubricating oil temperature T exceeds the second temperature setting value T2, the process proceeds to step S7. On the other hand, when the lubricating oil temperature T is equal to or lower than the second temperature set value T2, that is, when the lubricating oil temperature T exceeds the first temperature set value T1 and is equal to or lower than the second temperature set value T2, step S8 Go to.

In step S7, the opening / closing valve controller 36 opens the opening / closing valve 35, and the process proceeds to step S5. In this step S7, if the current state of the open / close valve 35 (the state before the signal is output from the open / close valve controller 36) is open, it remains open, and if it is closed, it opens. There is. Thereby, the main cooling passage 31 of the cooling system 30
Is released and lubricating oil is sprayed from the piston cooling nozzle 33, cooling of the piston 102 by the cooling system 30 is started, and the piston 102 can be cooled.
In step 8, the on-off valve controller 36 does not output a signal to the on-off valve 35, and the on-off valve 35
The present state of is maintained as it is, and the process proceeds to step S5. That is, the open / close valve 35 remains open if it is open, and remains closed if it is closed.

According to this embodiment as described above, the following effects can be obtained. That is, the open / close valve controller 3
6, the lubricating oil temperature T detected by the temperature sensor 37 is
When the first temperature set value T1 or less, the opening / closing valve 35 is closed to stop the cooling system 30, and when the second temperature set value T2 is exceeded, the opening / closing valve 35 is opened to start the cooling system 30. By appropriately setting the first temperature set value T1 and the second temperature set value T2, when the lubricating oil temperature T is low, that is, when the temperatures of the cylinder 101 and the piston 102 are low and the combustion temperature in the cylinder 101 is low, The cooling of the piston 102 can be stopped. This allows the cylinder 1
It is possible to accelerate the rise of the combustion temperature in 01, facilitate the ignition and complete combustion of the fuel, reduce the discharge of unburned fuel, and significantly reduce the discharge of white smoke. In addition, the piston 102 is based on the engine temperature affected by the outside air temperature.
Since the cooling of the piston 102 is started and stopped, it is possible to control the start and stop of the cooling of the piston 102 according to the temperature and the like as well as the state of the engine. Therefore, even when the engine is operated in cold regions and cold seasons, the piston 10
2 can be appropriately cooled.

In particular, in this embodiment, in the diesel engine using the water emulsion fuel having poor ignitability, the start / stop of cooling of the piston 102 is controlled based on the lubricating oil temperature T, so that the inside of the cylinder 101 is controlled. When the combustion temperature is low, that is, when the ignition of the water emulsion fuel is unlikely to occur, the piston cooling can be stopped. Therefore, even in the engine using the water emulsion fuel in which the combustion temperature in the cylinder 101 is unlikely to rise, the ignition and complete combustion of the fuel can easily occur, so that the emission of white smoke can be significantly reduced. On the other hand, when the lubricating oil temperature T is high, that is, when the temperatures of the cylinder 101 and the piston 102 are high and the combustion temperature in the cylinder 101 is high, the opening / closing valve controller 36 can activate the cooling system 30 to cool the piston 102. The temperature of the piston 102 can be prevented from rising excessively, and the durability of the diesel engine will not be impaired.

In the opening / closing valve controller 36, the first temperature set value T1 is set smaller than the second temperature set value T2, and the difference between the first temperature set value T1 and the second temperature set value T2 is 5 ° C. Since the lubricating oil temperature T is set to -10 ° C., the lubricating oil temperature T is changed in a small range within the range where the first temperature set value T1 is crossed, that is, even if hunting occurs, the lubricating oil temperature T Does not exceed the second temperature set value T2, so that the on-off valve controller 36 can solve the problem that the on-off valve 35 is repeatedly opened and closed in a short time only by keeping the on-off valve 35 closed. The durability of the open / close valve 35 is not impaired.

FIG. 7 shows a second embodiment of the present invention. This embodiment is the same as the first embodiment described above.
An open / close valve 35 is provided on the downstream side of the regulator valve 34, and the opening / closing of the open / close valve 35 is controlled to start / stop cooling of the piston 102 by the cooling system 30. Is provided and the two-way switching of the three-way valve 38 is controlled to start and stop the cooling of the piston 102 by the cooling system 30. In the present embodiment, the diesel engine piston cooling device includes an oil pan 11, an oil pump 12, and a cooling system 30 as piston cooling means, a three-way valve 38 and a three-way valve controller 39 as control means, and a temperature controller. The temperature sensor 37 as a detection unit, a pump discharge pressure introduction passage 381, a drain passage 382, and a pump discharge pressure supply passage 383 are included.

In FIG. 8, one end of a pump discharge pressure introducing passage 381, a drain passage 382, and a pump discharge pressure supply passage 383 are connected to the three-way valve 38. Here, the other end of the pump discharge pressure introducing passage 381 is connected to the upstream side of the regulator valve 34 in the main cooling passage 31. The other end of the drain passage 382 reaches the inside of the oil pan 11. Pump discharge pressure supply passage 38
3 is connected to a communication hole 341D that is formed on the bottom side of the regulator valve 34 and that connects the compression spring 342 side in the cylinder of the main body 341 and the outside. The three-way valve 38 is a two-position switching valve, and has a first position (FIG. 8) that connects the pump discharge pressure introduction passage 381 and the pump discharge pressure supply passage 383,
It has a second position (FIG. 9) that connects the pump discharge pressure supply passage 383 and the drain passage 382.

In the three-way valve 38 having such a structure and the regulator valve 34 described above, when the lubricating oil is discharged from the oil pump 12, the discharged lubricating oil passes through the pump discharge pressure introducing passage 381 and the three-way valve 38. And reaches the inlet 341A of the regulator valve 34. Here, when the position of the three-way valve 38 is the first position that connects the pump discharge pressure introduction passage 381 and the pump discharge pressure supply passage 383 as shown in FIG.
The lubricating oil that has reached 8 is the main body 3 of the regulator valve 34.
41 into the compression spring 342 side, and the valve body 343
Will be urged toward the step 341. Therefore, the valve element 343 is biased toward the step 341C (rightward in FIG. 8) by the spring pressure of the compression spring 342 and the discharge pressure of the oil pump 12. On the other hand, from the inlet 341A of the regulator valve 34 to the valve body 3
The lubricating oil that has reached the head of the oil pump 43 moves the valve element 343 toward the compression spring 342 side (leftward in FIG. 8) and the oil pump 1
It will be pushed with the discharge pressure of 2. Therefore, the compression spring 342
Since the force for urging the valve element 343 to the right in FIG. 8 is always large by the spring pressure of, the head of the valve element 343 has a step 341C.
The lubricating oil is blocked by the valve body 343, and the main cooling passage 31 is blocked by the regulator valve 34.

On the other hand, the position of the three-way valve 38 is, as shown in FIG. 9, a pump discharge pressure supply passage 383 and a drain passage 38.
When it is in the second position where it communicates with 2, the lubricating oil that has reached the three-way valve 38 is blocked by the three-way valve 38 because there is no passage that communicates with the pump discharge pressure introduction passage 381. Therefore, the valve body 343 is biased toward the step 341C (rightward in FIG. 8) only by the spring pressure of the compression spring 342. On the other hand, the lubricating oil reaching the head of the valve body 343 from the inlet 341A of the regulator valve 34 is
The valve body 343 is pushed by the discharge pressure of the oil pump 12 toward the compression spring 342 side (left direction in FIG. 9). Therefore, when the discharge pressure of the oil pump 12 exceeds the spring pressure of the compression spring 342, the valve body 343 is pushed by the lubricating oil and separated from the step 341C, and a gap is created between the valve body 343 and the step 341C. The lubricating oil passes through this gap and flows from the outlet 341B to the outside, that is, to the piston cooling nozzle 33 side.

The position of the three-way valve 38 is from the first position (FIG. 8) where the pump discharge pressure introducing passage 381 and the pump discharge pressure supplying passage 383 communicate with each other.
Second position (FIG. 9) that connects the drainage passage 382 with the drainage passage 382.
When switched to the second position, the lubricating oil flowing into the compression spring 342 side in the cylinder of the main body 341 of the regulator valve 34 when switched to the second position is switched to the second position, the pump discharge pressure supply passage 383 and the drain. Return to the oil pan 11 through the passage 382. For this reason, the valve body 343 moves toward the step 341C (rightward in FIG. 9) toward the compression spring 34.
It will be biased only by the spring pressure of 2.

The two-position switching of the three-way valve 38 is controlled by the three-way valve controller 39. The three-way valve controller 39, like the opening / closing valve controller 36 of the first embodiment, has the cooling system 30. As opposed to
When the lubricating oil temperature T stored in the oil pan 11 is equal to or lower than the first temperature set value T1, the main cooling passage 31 is shut off so that the lubricating oil cannot be sprayed from the piston cooling nozzle 33. Piston 102
Has stopped cooling. On the other hand, the three-way valve controller 39
When the lubricating oil temperature T stored in the oil pan 11 exceeds the second temperature set value T2, the main cooling passage 31 is opened to allow the lubricating oil to flow from the piston cooling nozzle 33 to the cooling system 30. And the cooling of the piston 102 by the cooling system 30 is started.

Specifically, although not shown, the three-way valve controller 39 has an input section for inputting a temperature signal from the temperature sensor 37 and an input section for determining the switching operation of the two-way switching of the three-way valve 38. An arithmetic processing unit as a determining unit that determines the state of the diesel engine based on the signal from the storage unit, a storage unit that stores information necessary for arithmetic processing performed by the arithmetic processing unit, and an arithmetic processing by the arithmetic processing unit. An output unit that outputs a predetermined signal to the three-way valve 38 based on the result. Here, the first temperature set value T1 is set smaller than the second temperature set value T2, and the difference between the first temperature set value T1 and the second temperature set value T2 is 5 ° C to 10 ° C.
The first temperature set value T1 and the second temperature set value T2 are stored in advance in the storage unit 362 of the three-way valve controller 39.

In the three-way valve controller 39 having such a structure, the lubricating oil temperature T detected by the temperature sensor 37 is detected.
However, if the temperature setting value is equal to or lower than the first temperature set value T1, the arithmetic processing unit outputs a signal for switching the three-way valve 38 to the first position (FIG. 8) to the three-way valve 38 to shut off the main cooling passage 31. Lubricant oil is prevented from being sprayed from the piston cooling nozzle 33, and the cooling of the piston 102 by the cooling system 30 is stopped. Then, the lubricating oil discharged from the oil pump 12 can be preferentially supplied to the lubricating system 20 (the lubricating passage 24). On the other hand, the lubricating oil temperature T is the second
When the temperature set value T2 is exceeded, the arithmetic processing unit causes the three-way valve 3
A signal for switching 8 to the second position is output to the three-way valve 38, the main cooling passage 31 is opened so that the lubricating oil can be sprayed from the piston cooling nozzle 33, and the cooling of the piston 102 by the cooling system 30 is started. is doing.
If the lubricating oil temperature T exceeds the first temperature set value T1 and is equal to or less than the second temperature set value T2, the arithmetic processing unit does not output a signal to maintain the current state of the three-way valve 38. It has become. That is, if the three-way valve 38 is in the first position, it remains in the first position, and if it is in the second position, it remains in the second position.

Also in this embodiment like this, it is possible to obtain the same operation and effect as those of the first embodiment.
That is, when the lubricating oil temperature T detected by the temperature sensor 37 is less than or equal to the first temperature set value T1 by the three-way valve controller 39, the three-way valve 38 is switched to the first position to stop the cooling system 30, and the second When the temperature set value T2 is exceeded, the three-way valve 38 is switched to the second position and the cooling system 30 is started. Therefore, if the first temperature set value T1 and the second temperature set value T2 are set appropriately, the lubricating oil When the temperature T is low, that is, when the temperatures of the cylinder 101 and the piston 102 are low and the combustion temperature in the cylinder 101 is low, the cooling of the piston 102 can be stopped. This allows the cylinder 1
The combustion temperature inside 01 can be promoted, and the emission of white smoke can be greatly reduced. On the other hand, when the lubricating oil temperature T is high, that is, when the temperatures of the cylinder 101 and the piston 102 are high and the combustion temperature in the cylinder 101 is high, the three-way valve controller 39 can activate the cooling system 30 to cool the piston 102. The temperature of the piston 102 can be prevented from rising excessively, and the durability of the diesel engine will not be impaired.

In the three-way valve controller 39,
The first temperature set value T1 is set smaller than the second temperature set value T2, and the difference between the first temperature set value T1 and the second temperature set value T2 is set to 5 ° C to 10 ° C. Even when so-called hunting occurs, in which the lubricating oil temperature T slightly fluctuates in a range that exceeds the first temperature set value T1, the lubricating oil temperature T exceeds the second temperature set value T2 in the temperature fluctuation. Since the three-way valve controller 39 simply keeps the three-way valve 38 in the first position, the problem that the two-position switching of the three-way valve 38 is repeated in a short time can be solved by the three-way valve controller 39, and the three-way valve 38 can be durable. There is no loss of sex.

The present invention is not limited to the above-described embodiments, and modifications and improvements within the range in which the object of the present invention can be achieved are included in the present invention. For example,
The first temperature set value, the second temperature set value, and the temperature detected by the temperature detecting means are not limited to the temperature of the lubricating oil, but may be the temperature of the refrigerant for cooling the engine, or the like.
The first temperature set value and the second temperature set value do not have to be different values, and may be the same value. Further, the engine is not limited to an engine using water emulsion fuel, but may be an engine using a corrosive liquid such as decomposed fuel oil of waste plastic as a fuel, or another fuel for private use. It may be an engine that does. Furthermore, the engine may be a naturally aspirated engine that does not perform supercharging.

In each of the above-described embodiments, the on-off valve controller 36 for controlling the operation of the on-off valve 35 and the three-way valve controller 39 for controlling the operation of the three-way valve 38 are constituted by a single unit. ,
It may be configured by being incorporated in an engine controller that controls the amount of fuel supplied into the cylinder of the diesel engine. Various information such as engine load, rotation speed, fuel injection amount, lubricating oil temperature, and cooling water temperature are input to the engine controller in order to control the engine based on the operating conditions of the diesel engine. Each engine controller 36, 38
If the function of is incorporated, the temperature sensor 3 provided separately
7 becomes unnecessary. Further, the piston cooling means is not limited to the one integrated with the engine lubrication system, and may be provided separately. For example, in each of the above-described embodiments, the cooling system and the lubrication system may be combined. A dedicated oil pump may be provided separately for each. In such a case, the start / stop of cooling of the piston may be controlled by controlling the operation of the oil pump dedicated to the cooling system.

Further, the judging means is not limited to the one for judging the state of the engine on the basis of the temperature of the engine, but the judging means for judging the state of the engine on the basis of the elapsed time from the start of the engine, the judging means on the basis of the load of the engine. It may be a determining means for determining the state of the engine based on the amount of fuel supplied into the cylinder of the engine, a determining means for determining the state of the engine based on the output of the engine. .

Here, as the determining means for determining the state of the engine based on the elapsed time from the engine start, when the engine is started, a timer or the like starts time measurement, and when a predetermined time elapses, for example, the above-mentioned first In the embodiment, a signal for opening the valve may be output to the on-off valve 35 to open the main cooling passage 31, or in the above-described second embodiment, the switching position of the three-way valve 38. The main cooling passage 31 may be opened by outputting a signal for switching to the second position (FIG. 9). It should be noted that the predetermined time may be a time when the combustion temperature in the cylinder is sufficiently increased after the engine is started and the fuel is easily ignited and completely combusted. It may be obtained in advance, etc.
According to such a determination means, it is possible to start the piston cooling after a predetermined time has elapsed from the engine start, so that it is possible to avoid cooling the piston at the time of engine start when the cylinder and the piston are normally cooled,
It is possible to promote the rise of the combustion temperature in the cylinder. Therefore, in a short time after the engine is started, ignition and complete combustion of fuel can easily occur, unburned fuel discharge can be reduced, and white smoke discharge can be significantly reduced. Further, if the predetermined time is appropriately set, cooling of the piston can be started after the combustion temperature in the cylinder has risen to a sufficient temperature.
The piston temperature can be prevented from rising excessively, and the durability of the engine will not be impaired.

Further, as the judging means for judging the state of the engine based on the load of the engine, when the engine load detected by the load detecting means is equal to or less than the first load set value, in the above-mentioned first embodiment, A signal for closing the valve may be output to the on-off valve, and when the second load set value is exceeded, a signal for closing the valve may be output to the on-off valve, or in the second embodiment described above. Is
A signal for switching the switching position of the three-way valve 38 to the first position (FIG. 8) is output when the load is less than or equal to the first load set value, and the switching position of the three-way valve 38 is switched when the second load set value is exceeded. A signal for switching to the second position (FIG. 9) may be output. The first load setting value and the second load setting value may be the same value or different values. If they are different values, the first load setting value is the second load setting value. It is set to a value smaller than the set value. Here, as the load detecting means for detecting the load state of the engine, a sensor for detecting the engine torque, a sensor for detecting the accelerator opening, and the output of the generator when the engine is used for the generator It may be a sensor that detects,
Alternatively, a sensor or the like for detecting the amount of fuel supplied into the cylinder of the engine may be used, in short, any sensor may be used as long as it detects a change in engine parameters that is substantially proportional to the load state of the engine.

According to such a judging means, the piston cooling means is stopped when the engine load detected by the load detecting means is less than or equal to the first load set value, and the piston cooling means is stopped when the engine load exceeds the second load set value. Since the cooling means is activated, the first
By appropriately setting the load set value and the second load set value, the cooling of the piston by the piston cooling means can be stopped when the engine load is low, that is, when the fuel supplied to the cylinder is small and the combustion temperature is low. . As a result, it is possible to accelerate the rise of the combustion temperature in the cylinder, facilitate the ignition and complete combustion of the fuel, reduce the discharge of unburned fuel, and significantly reduce the discharge of white smoke. On the other hand, when the engine load is high, that is, when the amount of fuel injected / supplied into the cylinder is large and the combustion temperature is high, the piston cooling means can be activated to cool the piston, so the temperature of the piston rises excessively. Can be prevented and the durability of the engine is not impaired. And
By setting the first load setting value to be smaller than the second load setting value, the fuel supply amount to the cylinder may exceed the first load setting value (or the second load setting value) as in the above-described embodiments. It becomes possible to deal with so-called hunting, which fluctuates in a small range, and it is possible to deal with engine malfunctions due to hunting.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a lubrication system including a piston cooling device for a diesel engine according to a first embodiment of the present invention.

FIG. 2 is an enlarged perspective view showing a piston and a piston cooling nozzle in the embodiment.

FIG. 3 is a sectional view showing a regulator valve in the embodiment.

FIG. 4 is a block diagram showing an on-off valve controller in the embodiment.

FIG. 5 is a diagram for explaining the operation of the on-off valve controller in the embodiment.

FIG. 6 is a flowchart for explaining the operation of the embodiment.

FIG. 7 is a schematic configuration diagram showing a lubrication system including a diesel engine piston cooling device according to a second embodiment of the present invention.

FIG. 8 is a schematic diagram showing a three-way valve and a regulator valve in the embodiment.

9 is a schematic diagram for explaining the operation of the regulator valve when the position of the three-way valve shown in FIG. 8 is switched to another position.

[Explanation of symbols]

11 Oil pan that is piston cooling means 12 Oil pump as piston cooling means 30 Piston cooling means cooling system 31 main cooling passage which is an oil passage 32 Branch cooling passage that is an oil passage 35 On-off valve as stop means and start means 37 Temperature sensor which is a temperature sending means 38 Three-way valve as stop means and start means 101 cylinder 102 piston 361 Arithmetic processing unit that is a determination means T1 first temperature set value T2 second temperature set value

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F01M 7/00 F01M 7/00 C F01P 3/08 F01P 3/08 A 7/14 7/14 Z (72 ) Inventor Hiroyasu Sato 400 Yokokura Nitta 400, Oyama City, Tochigi Prefecture F-term in IPA Co., Ltd. (reference) 3G013 AA07 BA02 BB14 BB25 BB32 BC03 BC04 BD02 CA06 EA03 EA05 EA08 EA09

Claims (6)

[Claims] 1. A diesel engine piston cooling device for a diesel engine, comprising: a cylinder (101); and a piston (102) sliding in the cylinder (101), the piston cooling device comprising: Piston cooling means (11, 1) that blows a refrigerant to cool the piston (102).
2, 30) and control means (35, 36, 38, 39) for controlling the operation of the piston cooling means (11, 12, 30), and the control means (35, 36, 38, 39) is , A determination means (361) for determining the state of the diesel engine and a signal from the determination means (361) for determining whether to start or stop the piston cooling means (11, 12, 30). And a starting means (35, 38) for starting the piston cooling means (11, 12, 30) based on the above, and the determination means (361) starts timing when the diesel engine starts, A piston cooling device for a diesel engine, which outputs a predetermined signal to the starting means (35, 38) when a predetermined time has elapsed. 2. A piston cooling device for a diesel engine provided in a diesel engine, comprising: a cylinder (101); and a piston (102) sliding in the cylinder (101), the piston (102) comprising: Piston cooling means (11, 1) that blows a refrigerant to cool the piston (102).
2, 30), load detecting means for detecting the load state of the diesel engine, and control means (35, 36, 38, 39) for controlling the operation of the piston cooling means (11, 12, 30). The control means (35, 36, 38, 39) determines the state of the diesel engine in order to determine whether to start or stop the piston cooling means (11, 12, 30). 361), starting means (35, 38) for starting the piston cooling means (11, 12, 30) based on the signal from the judging means (361), and the signal from the judging means (361). Stop means (35, 38) for stopping the piston cooling means (11, 12, 30) based on the above, and the determination means (361) is detected by the load detection means. And when the load is equal to or smaller than the first load set value, when a predetermined signal and outputs the to stop means (35, 38) load, detected by the load detecting means exceeds the second load set value,
A piston cooling device for a diesel engine, which outputs a predetermined signal to the starting means (35, 38). 3. The piston cooling device for a diesel engine according to claim 2, wherein the first load set value is set smaller than the second load set value. apparatus. 4. A piston cooling device for a diesel engine provided in a diesel engine, comprising: a cylinder (101); and a piston (102) sliding in the cylinder (101). Piston cooling means (11, 1) that blows a refrigerant to cool the piston (102).
2, 30), temperature detecting means (37) for detecting the temperature (T) of the diesel engine, and control means (35, 36, 38,) for controlling the operation of the piston cooling means (11, 12, 30). 39), the control means (35, 36, 38, 39) controls the state of the diesel engine in order to determine whether to start or stop the piston cooling means (11, 12, 30). Determination means (361) for determining, activation means (35, 38) for activating the piston cooling means (11, 12, 30) based on a signal from the determination means (361), and the determination means (361) ) And a stop means (35, 38) for stopping the piston cooling means (11, 12, 30) based on a signal from the above), the determination means (361) includes the temperature detection means. Stage (37)
When the temperature (T) detected in step 1 is less than or equal to the first temperature set value (T1), a predetermined signal is output to the stop means (35, 38) and the temperature (T) detected in the temperature detection means (37). )
Is a second temperature set value (T2), a predetermined signal is output to the starting means (35, 38). 5. The piston cooling device for a diesel engine according to claim 4, wherein the first temperature set value (T1) is set smaller than the second temperature set value (T2). Piston cooling system for diesel engine. 6. The piston cooling device for a diesel engine according to claim 1, wherein the piston cooling means (11, 12, 30) pumps an oil pump for pumping lubricating oil of the diesel engine. 12) and a nozzle (33) for spraying the lubricating oil discharged from the oil pump (12) toward the piston (102).
And an oil passage (31, 32) for guiding the lubricating oil discharged from the oil pump (12) to the nozzle (33), and the stopping means (35, 38) includes the oil passage ( Three
1, 32) is cut off, and the starting means (35, 38) is provided with the oil passage (3
1, 32) is opened, and a piston cooling device for a diesel engine.