JP2020153304A - engine - Google Patents

Abstract

To provide an engine which enables a quantity of hydraulic oil in a crank case to be accurately confirmed while the engine is in operation.SOLUTION: An engine comprises: a crank case 13 which has a hydraulic oil storage section 13a; first and second communication holes 133 and 134 which communicate an inside of the crank case with an outside thereof; a hydraulic oil passage 135 which connects the first and second communication holes and allows hydraulic oil to flow thereinto through the first communication hole with motion of a displacer piston yoke 51; a flowmeter 137 which measures a flow rate of the hydraulic oil flowing into the hydraulic oil passage; a hydraulic quantity detection section which can detect that a quantity of the hydraulic oil in the hydraulic oil storage section is equal to or lower than a predetermined quantity by calculating the same on the basis of the flow rate when an engine rotation speed is equal to or higher than a predetermine rotation speed; and an operation execution section which controls the engine rotation speed to be equal to or higher than the predetermined rotation speed when the same is lower than the predetermined rotation speed and executes predetermined operation when the hydraulic quantity detection section detects that the quantity of hydraulic oil is equal to or lower than the predetermined quantity.SELECTED DRAWING: Figure 1

Description

The present invention relates to an engine.

The following Patent Document 1 discloses a configuration in which a Stirling engine in which a display support piston and a power piston are housed in the same cylinder, a crankshaft connected to the display support piston and the power piston is sealed in a crankcase, and lubricating oil is stored in the crankcase. Has been done. Further, a configuration is disclosed in which a lubrication valve and an oil return valve that open and close by utilizing the pressure fluctuation in the crankcase due to the reciprocating movement of the power piston are provided to circulate the lubricating oil.

However, since the Stirling engine seals an inert gas as a working gas, the internal pressure of the crankcase is higher than that of a normal engine, and in such a high static pressure state, the amount of lubricating oil can be detected by the hydraulic switch. Have difficulty. In a situation where the Stirling engine is operated by waste heat by installing it in the flue of an incinerator, it is always in an operating state during the period when the waste heat is supplied, so it is essential to detect the amount of lubricating oil during operation. In addition, this oil amount detection needs to be unaffected by the engine speed.

However, Patent Document 1 does not disclose any configuration or control for confirming the amount of lubricating oil in the crankcase during engine operation.

Japanese Unexamined Patent Publication No. 62-20396

Therefore, in view of the above problems, it is an object of the present invention to provide an engine capable of accurately confirming the amount of lubricating oil in the crankcase during engine operation.

The engine of the present invention has a reciprocating piston and
A crankshaft that can rotate by the reciprocating movement of the piston,
A connecting member that connects the piston and the crankshaft,
A crankcase that supports the crankshaft and has a lubricating oil storage portion that stores lubricating oil.
A first communication hole formed in the lubricating oil storage portion and communicating with the inside and outside of the crankcase,
A second communication hole formed at a position away from the lubricating oil storage portion and communicating with the inside and outside of the crankcase,
A lubricating oil path in which the first communication hole and the second communication hole are connected outside the crankcase and the lubricating oil flows in from the first communication hole due to the movement of the connecting member.
A flow rate measuring device that measures the flow rate of the lubricating oil that has flowed into the lubricating oil path, and
When the engine speed is equal to or higher than the predetermined speed, the amount of lubricating oil in the lubricating oil storage section is calculated based on the flow rate, and the oil amount detection unit capable of detecting that the amount of oil is equal to or lower than the predetermined amount. When,
When the engine speed is lower than the predetermined speed, the engine speed is controlled to be equal to or higher than the predetermined speed, and the oil amount detection unit increases the amount of lubricating oil in the lubricating oil storage unit to a predetermined amount. It is provided with an operation execution unit that executes a predetermined operation when it is detected to be the following.

In the engine of the present invention, an oil temperature measuring device for measuring the temperature of the lubricating oil and
Even those provided with an oil amount correction unit that corrects the oil amount of the lubricating oil in the lubricating oil storage unit calculated by the oil amount detection unit according to the temperature of the lubricating oil measured by the oil temperature measuring device. Good.

The engine of the present invention includes a lubricating oil supply tank connected to the crankcase via a solenoid valve.
When the operation executing unit detects that the amount of lubricating oil in the lubricating oil storage unit is equal to or less than a predetermined amount by the oil amount detecting unit, the operation executing unit opens the solenoid valve and puts the lubricating oil supply tank in the crankcase. Lubricating oil may flow in from.

In the engine of the present invention, a tubular shape that is erected on the inner surface of the crankcase and around the first communication hole and accommodates at least a part of the connecting member when the piston is located at the bottom dead center. Parts and
It may be provided with at least one side hole formed on the side surface of the tubular member and communicating inside and outside the tubular member.

The engine of the present invention includes a motor generator connected to one end side of the crankshaft.
When the engine speed is lower than the predetermined speed, the motor generator may perform power running operation so that the engine speed becomes the predetermined speed.

According to the present invention, the flow rate of the lubricating oil that has flowed into the lubricating oil path due to the movement of the connecting member that moves in conjunction with the piston is measured, and the amount of lubricating oil in the lubricating oil storage portion is calculated from this flow rate. The amount of oil can be detected while the engine is running. Further, even when the engine speed is low, the oil amount detection unit can accurately detect the oil amount by controlling the engine speed to be equal to or higher than the predetermined speed.

It is the schematic which shows the side cross section of the Stirling engine which concerns on 1st Embodiment. It is the schematic which shows the front cross section of the Stirling engine of FIG. It is a schematic diagram which shows the part of the Stirling engine of FIG. 1 enlarged. It is a block diagram which shows the control composition of a Stirling engine. It is a figure which shows the map which associated the flow rate and the oil retention amount. It is a flowchart which shows an example of the oil amount detection from the start of an engine to the operation. It is a graph which shows an example of the oil amount detection operation. It is a flowchart which shows an example of the oil amount detection at the time of engine stop. It is a figure which shows the temperature dependence of the map which associated the flow rate and the oil retention amount. It is the schematic which shows the side cross section of the Stirling engine which concerns on 2nd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a schematic view showing a side cross section of the Stirling engine 1, and FIG. 2 is a schematic view showing a front cross section of the Stirling engine 1. Further, FIG. 3 is a schematic view showing an enlarged part of the Stirling engine 1 of FIG. In the following, the β-type Stirling engine 1 will be described as an example.

As shown in FIGS. 1 and 2, in the Stirling engine 1, the displacer piston 3 and the power piston 4 are reciprocally housed inside a cylinder 2 in which working gases such as air, helium gas, and hydrogen are sealed. ing.

The cylinder 2 has a configuration in which one end is opened while the other end is closed, and the displacer piston 3 is arranged on the closed end side, while the power piston 4 is arranged on the open end side. In the cylinder 2, an expansion space 5 is formed between the closed end portion and the display support piston 3, and a compression space 6 is formed between the display support piston 3 and the power piston 4. The expansion space 5 and the compression space 6 in the cylinder 2 are collectively referred to as an operating space.

The Stirling engine 1 is provided with a heat exchanger 7 that raises and lowers the temperature of the working gas in the working space in the cylinder 2. The heat exchanger 7 includes a heater 8 that communicates with the expansion space 5 and heats the working gas by heat input from the outside, a cooler 9 that communicates with the compression space 6 and cools the working gas by heat radiation to the outside, and a heater. The regenerator 10 for connecting the 8 and the cooler 9 is provided. When the displacer piston 3 moves toward the open end side of the cylinder 2, the working gas heated by the heater 8 flows into the expansion space 5, and the temperature of the working gas rises. On the other hand, when the displacer piston 3 moves toward the closed end side of the cylinder 2, the working gas cooled by the cooler 9 flows into the compression space 6, and the temperature of the working gas drops. Therefore, the working gas flows forward and backward between the heat exchanger 7 and the working space in the cylinder 2, so that the internal pressure in the working space of the cylinder 2 changes, and the reciprocating movement of the power piston 4 is promoted.

One end of the heater 8 communicates with the expansion space 5, and the other end communicates with one end of the regenerator 10. The heater 8 heats the working gas passing through the inside by receiving the heat of the exhaust gas generated in the incinerator or the like. Although only two tubular heaters 8 are shown in FIGS. 1 and 2, a large number of heaters 8 are actually provided.

The other end of the regenerator 10 communicates with the cooler 9. Further, the cooler 9 communicates with the compression space 6. Cooling water flows in the cooler 9 so as to be heat exchangeable with the working gas, and the working gas is cooled by this heat exchange.

The regenerator 10 and the cooler 9 are arranged on the outer peripheral portion of the cylinder 2. The regenerator 10 is composed of, for example, one in which metal fibers and wire nets are laminated, one in which the flow paths of working gas are arranged in a honeycomb shape, and one in which cotton-like metal fibers are included. Functions as a heat storage type heat exchanger. That is, the regenerator 10 stores heat of the working gas when the high-temperature working gas flows from the heater 8 to the cooler 9, while the regenerator 10 stores heat when the low-temperature working gas flows from the cooler 9 to the heater 8. The generated heat is dissipated to the working gas.

The Stirling engine 1 is provided with an output extraction device 11 on the open end side of the cylinder 2 that converts the reciprocating motion of the power piston 4 into a rotary motion and outputs rotary power. The output take-out device 11 pivotally supports a crankshaft 12 connected to each of the displacer piston 3 and the power piston 4 in the crankcase 13. Then, one end side of the crankshaft 12 serves as an output shaft, which is connected to the input shaft 16 of the motor generator 15 via the flywheel 14 in the crankcase 13. Further, a buffer space 17 is formed by a space 17a on the opening end side of the power piston 4 in the cylinder 2 and a space 17b in the crankcase 13.

The displacer piston 3 and the power piston 4 reciprocate in the cylinder 2 with a predetermined phase difference by connecting to the crankshaft 12 of the output extraction device 11. In the present embodiment, the phase difference in the reciprocating operation of the display piston 3 and the power piston 4 is 90 °.

The output take-out device 11 includes a plate 51c fixed to the crankshaft guide groove (through groove) 51a of the displacer piston yoke 51 that reciprocates according to the display piston 3, and a power piston yoke that reciprocates according to the power piston 4. Crankpins 54 to 56 of the crankshaft 12 are fitted to the plates 52c and 53c fixed to the crankshaft guide grooves (through grooves) 52a and 53a of the reciprocating parts) 52 and 53 via bearings 57 to 59, respectively. It is composed of a scotch yoke mechanism.

As shown in FIG. 2, the display support piston yoke 51 is provided with a long crankshaft guide groove 51a in the central portion thereof in a direction (lateral direction) intersecting the axial directions of the crankshaft 12 and the display support piston 3. There is. Reciprocating guide holes (through holes) 51b are bored in the displayer piston yoke 51 on both sides of the crankshaft guide groove 51a in the axial direction (longitudinal direction) of the displayer piston 3. A guide shaft 60 fixed to the crankcase 13 is inserted into the reciprocating guide hole 51b of the displacer piston yoke 51 via a linear motion bearing 63 such as a rotor rib bushing. The display support piston yoke 51 is connected to the other end of the rod 66 whose one end is connected to the display support piston 3, and reciprocates in the same direction (vertical direction) as the display support piston 3 in accordance with the reciprocating movement of the display support piston 3.

As shown in FIG. 2, the power piston yoke 52 is provided with a crankshaft guide groove 52a long in the lateral direction in the central portion thereof, and reciprocating guide holes (reciprocating guide holes) are provided on both sides of the crankshaft guide groove 52a. (Through hole) 52b is bored in the vertical direction. A guide shaft 61 fixed to the crankcase 13 is inserted into the reciprocating guide hole 52b of the power piston yoke 52 via a linear motion bearing 64. The power piston yoke 52 is connected to the other end of the bridge 67 whose one end is connected to the power piston 4, and reciprocates in the vertical direction in accordance with the reciprocating movement of the power piston 4. Since the power piston yoke 53 has the same shape as the power piston yoke 52, detailed description thereof will be omitted.

As shown in FIGS. 1 and 2, through holes 4a and 67a are provided at the centers of the power piston 4 and the bridge 67 in the direction (longitudinal direction) along the axial direction of the power piston 4, and the display piston 3 and the display piston 3 are provided. The connected rod 66 is pierced. The rod 66 is movable relative to the power piston 4 and the bridge 67, and a dynamic sealing mechanism (not shown) such as a mechanical seal is configured at the insertion portion of the rod 66 in the power piston 4.

As shown in FIG. 1, the crankshaft 12 is connected between the bridge 67 and the crank pins 55 and 56 connected via the power piston yokes 52 and 53, and the crank pin 54 connected via the rod 66 and the displacer piston yoke 51. Is provided, and the crank pin 54 is attached to the crank pins 55 and 56 having the same phase with a predetermined phase difference (for example, 90 °). A bridge insertion hole 68 into which the bridge 67 is inserted is provided in the connecting portion of the crankcase 13 with the cylinder 2. The bridge insertion hole 68 of the crankcase 13 is formed in a connecting portion between the cylinder 2 and the crankcase 13, so that the cylinder 2 side portion of the bridge 67 is inserted and removed from the bridge insertion hole 68. Reciprocates according to the power piston 4. In order to reduce the fluctuation of the internal pressure due to the volume change due to the reciprocating movement of the power piston 4 in the buffer space 17a on the opening end side of the power piston 4 in the cylinder 2, the buffer space 17a in the cylinder 2 and the inside of the crankcase 13 A communication port 17d is provided between the buffer space 17b and the buffer space 17b.

The displacer piston 3 reciprocates with the rotational power of the crankshaft 12, and the working gas moves back and forth between the expansion space 5 and the compression space 6, so that the internal pressure of the working space changes. Due to this pressure change, the power piston 4 reciprocates, and the reciprocating power is transmitted to the power piston yokes 52 and 53 via the bridge 67. As a result, the power piston yokes 52 and 53 reciprocate in the vertical direction along the guide shafts 61 and 62, respectively. Then, the reciprocating motion of the power piston yokes 52 and 53 causes the crankshafts 12 to rotate by reciprocating in the lateral direction while the crankpins 55 and 56 rotate in the crankshaft guide grooves 52a and 53a, respectively. Therefore, the output take-out device 11 that receives the reciprocating power of the power piston 4 converts it into rotational power by the Scotch yoke mechanism and outputs it from the crankshaft 12, and transmits the motor generator 15 via the flywheel 14 and the input shaft 16. Rotate. Power is generated by the rotation of the motor generator 15.

The crankcase 13 includes a lubricating oil storage unit 13a for storing lubricating oil to be supplied to a sliding portion of the output extraction device 11. The lubricating oil storage portion 13a is determined by the installation posture of the Stirling engine 1 and corresponds to the lower portion in the vertical direction in the crankcase 13.

An inner cylinder 131 (corresponding to a tubular member) is erected on the inner surface of the crankcase 13 and in the lubricating oil storage portion 13a. As shown in FIG. 1, the inner cylinder 131 extends in a direction (longitudinal direction) along the axial direction of the displacer piston 3. The inner cylinder 131 is configured to accommodate at least a part of the displacer piston yoke 51 or the power piston yokes 52, 53 when the displacer piston 3 or the power piston 4 is located at the bottom dead center. That is, the displacer piston yoke 51 or the power piston yokes 52, 53 correspond to the connecting member of the present invention. In the present embodiment, the inner cylinder 131 is arranged so as to accommodate a part of the displacer piston yoke 51. The side surface 131a of the inner cylinder 131 is arranged between the displacer piston yoke 51 and the power piston yokes 52 and 53.

At least one side hole 132 that communicates with the inside and outside of the inner cylinder 131 is formed on the side surface 131a of the inner cylinder 131. The side hole 132 functions as a suction hole for sucking lubricating oil into the inner cylinder 131.

A first communication hole 133 that communicates with the inside and outside of the crankcase 13 is formed on the inner surface of the crankcase 13 surrounded by the inner cylinder 131. The first communication hole 133 functions as a discharge hole for discharging the lubricating oil to the outside of the crankcase 13.

In the section where the display piston 3 moves to the bottom dead center, that is, in the section where the display piston yoke 51 moves in the direction approaching the first communication hole 133, the pressure of the lubricating oil in the inner cylinder 131 increases, as shown in FIG. Lubricating oil is discharged from the first communication hole 133 to the outside of the crankcase 13. On the other hand, in the section where the display support piston 3 moves to the top dead center, that is, in the section where the display support piston yoke 51 moves in the direction away from the first communication hole 133, the pressure of the lubricating oil in the inner cylinder 131 drops, and the inner cylinder 131 Lubricating oil flows into the inside. At this time, since the side hole 132 is provided on the side surface 131a of the inner cylinder 131, the lubricating oil easily flows into the inner cylinder 131 from the side hole 132 as shown in FIG.

The opening area of the first communication hole 133 is preferably larger than the total opening area of the side hole 132. When the opening area of the first communication hole 133 is smaller than the total opening area of the side hole 132, the displacer piston yoke 51 moves in the direction approaching the first communication hole 133, and the pressure of the lubricating oil in the inner cylinder 131 increases. In this case, the lubricating oil is likely to be discharged to the outside of the crankcase 13 from the side hole 132 instead of the first communication hole 133.

A second communication hole 134 that communicates with the inside and outside of the crankcase 13 is formed on the inner surface of the crankcase 13 at a position away from the lubricating oil storage portion 13a. That is, the second communication hole 134 is provided at a position higher in the vertical direction than the oil level of the lubricating oil in the crankcase 13. The second communication hole 134 functions as a return hole for returning the lubricating oil discharged from the first communication hole 133 to the crankcase 13.

The first communication hole 133 and the second communication hole 134 are connected by a lubricating oil path 135 provided outside the crankcase 13. The lubricating oil discharged from the first communication hole 133 flows to the second communication hole 134 via the lubricating oil path 135. The lubricating oil path 135 is provided with a check valve 136 whose forward direction is from the first communication hole 133 to the second communication hole 134. By providing the check valve 136, it is possible to prevent the lubricating oil in the lubricating oil path 135 from flowing back to the first communication hole 133 side.

Further, the lubricating oil path 135 is provided with a flow meter 137 (corresponding to a flow rate measuring device) on the second communication hole 134 side of the check valve 136. The flow meter 137 can measure the flow rate of the lubricating oil that has flowed into the lubricating oil path 135. This makes it possible to confirm the presence or absence of lubricating oil in the crankcase 13 that circulates through the lubricating oil path 135. As the flow meter 137, for example, a turbine flow meter can be used.

Further, in the lubricating oil path 135, a temperature sensor 138 (corresponding to an oil temperature measuring device) is provided between the check valve 136 and the flow meter 137. The temperature sensor 138 measures the temperature of the lubricating oil in the lubricating oil path 135.

The control device 70 that controls the Stirling engine 1 includes an oil amount detection unit 71, a storage unit 72, an operation execution unit 73, and a motor control unit 74.

When the engine rotation speed is equal to or higher than the predetermined rotation speed, the oil amount detection unit 71 increases the amount of lubricating oil (both oil retention amount) of the lubricating oil storage unit 13a based on the flow rate of the lubricating oil measured by the flow meter 137. It is possible to detect that the calculated oil retention amount is less than or equal to the predetermined amount. The "predetermined amount" is an oil retention amount that does not cause problems such as seizure. Specifically, the oil amount detection unit 71 acquires the oil retention amount associated with the flow rate from the map associated with the flow rate and the oil retention amount stored in advance in the storage unit 72. As shown in FIG. 5, the measured flow rate differs depending on the oil retention amount, and the oil retention amount can be calculated by measuring the flow rate.

However, as shown in FIG. 5, the magnitude of the flow rate with respect to the oil retention amount differs depending on the engine speed. It is considered that this is because when the engine speed is low, the descending speed of the displacer piston yoke 51 is slow, the speed at which the lubricating oil is pumped into the lubricating oil path 135 is slowed down, and the flow rate of the lubricating oil is reduced.

By the way, since the flow meter 137 has a dead zone and it is difficult to detect a small flow rate, the flow rate cannot be measured appropriately when the engine speed is low, and the oil retention amount may not be calculated correctly. Therefore, the oil amount detection unit 71 of the present invention calculates the oil retention amount based on the flow rate when the engine speed is equal to or higher than the predetermined speed.

The motor control unit 74 controls the motor generator 15, and when the engine speed is lower than the predetermined speed, the motor generator 15 is power-run controlled. As a result, the motor generator 15 performs power running operation so that the engine speed becomes a predetermined speed.

When the oil amount detecting unit 71 detects that the oil amount (oil retention amount) of the lubricating oil in the lubricating oil storage unit 13a is equal to or less than a predetermined amount, the operation executing unit 73 executes a predetermined operation. The predetermined operation is, for example, an alarm issuance, lubricating oil is replenished, an engine is stopped, or the like. In the present embodiment, the operation execution unit 73 commands the notification device 80, such as a monitor or a speaker, to execute the notification.

Next, the method for detecting the amount of oil in the Stirling engine 1 will be described. FIG. 6 is a flowchart showing an example of oil amount detection from the start of the engine to the operation. FIG. 7 is a graph showing an example of the oil amount detection operation.

When the engine start signal is turned on in step S101, the engine is started by the power running operation of the motor generator 15.

In step S102, the engine speed is set to the oil retention amount detection mode set speed Nd (corresponding to a predetermined speed) by the power running operation of the motor generator 15. The engine speed is held for Td seconds at the oil retention detection mode set speed Nd.

In step S103, the engine speed Ne is measured and the oil temperature is measured. The engine speed Ne is measured by the motor generator 15 or a speed measuring device (not shown). The oil temperature is measured by the temperature sensor 138.

In step S104, the oil retention amount Q is calculated based on the flow rate measured by the flow meter 137. Further, in step S104, the timer T is reset.

In step S105, it is determined whether or not the oil retention amount Q is equal to or less than the oil retention lower limit value Qc (corresponding to a predetermined amount). When the oil retention amount Q is equal to or less than the oil retention lower limit value Qc in step S105, an alarm indicating a decrease in oil amount is issued in step S106.

On the other hand, when the oil retention amount Q is larger than the oil retention lower limit value Qc in step S105, the power generation operation is continued in step S107.

In step S108, it is determined whether or not the engine speed Ne is equal to or higher than the oil retention detection mode set speed Nd. When the engine speed Ne is equal to or higher than the oil retention detection mode set speed Nd in step S108, the process returns to step S103.

On the other hand, when the engine speed Ne is lower than the oil retention detection mode set speed Nd in step S108, the timer count is started in step S109.

After that, in step S110, it is determined whether or not the timer T has reached the oil retention amount detection interval Tc. When the timer T reaches the oil retention detection interval Tc, the process returns to S102 to start the oil retention detection mode. On the other hand, when the timer T has not reached the oil retention amount detection interval Tc, the process returns to S107 and the power generation operation is continued.

FIG. 8 is a flowchart showing an example of oil amount detection when the engine is stopped.

When the engine stop signal is turned on in step S201, the engine is stopped in step S202.

In step S203, the engine is restarted by the power running operation of the motor generator 15 after T2 seconds.

In step S204, the engine speed is set to the oil retention amount detection mode set speed Nd (corresponding to a predetermined speed) by the power running operation of the motor generator 15. The engine speed is held for Td seconds at the oil retention detection mode set speed Nd.

In step S205, the engine speed Ne is measured and the oil temperature is measured.

In step S206, the oil retention amount Q is calculated based on the flow rate measured by the flow meter 137. Further, in step S206, the timer T is reset.

In step S207, it is determined whether or not the oil retention amount Q is equal to or less than the oil retention lower limit value Qc (corresponding to a predetermined amount). When the oil retention amount Q is equal to or less than the oil retention lower limit value Qc in step S207, an alarm indicating a decrease in the oil amount is issued in step S208.

On the other hand, when the oil retention amount Q is larger than the oil retention lower limit value Qc in step S207, the engine stop signal is turned on in step S209. Then, in step S210, the engine is stopped.

By the way, the flow rate of the lubricating oil depends on the temperature. Specifically, as the temperature decreases, the viscosity increases, so the flow rate tends to decrease. FIG. 9 is a diagram showing the temperature dependence of the map associating the flow rate with the oil retention amount. As shown in FIG. 9, at low temperature, the flow rate measured by the flow meter 137 is smaller than that at high temperature even if the amount of oil retained is the same. As a result, if a map at a reference temperature is used at a low temperature, the amount of oil retained will be underestimated. Therefore, the control device 70 corrects the oil amount of the lubricating oil in the lubricating oil storage unit 13a calculated by the oil amount detecting unit 71 according to the temperature of the lubricating oil measured by the temperature sensor 138. It is preferable to provide.

[Second Embodiment]
In the first embodiment, when the amount of oil decreases, only an alarm indicating the decrease in the amount of oil is issued, but the lubricating oil may be automatically replenished.

FIG. 10 shows an example in which the Stirling engine 1 is provided with the lubricating oil supply tank 139. Since the same reference numerals have the same functions in the first embodiment and the second embodiment, the description thereof will be omitted.

The lubricating oil supply tank 139 stores the lubricating oil supplied to the inside of the crankcase 13. The lubricating oil supply tank 139 is provided on the outside of the crankcase 13 and is connected to the crankcase 13 by a supply path 140. The supply path 140 is connected to the upper part of the crankcase 13. The supply path 140 is provided with a solenoid valve 141 capable of opening and closing the flow path in the supply path 140. Normally, the solenoid valve 141 is closed.

When the operation executing unit 73 detects that the amount of lubricating oil in the lubricating oil storage unit 13a is equal to or less than a predetermined amount by the oil amount detecting unit 71, the operation executing unit 73 opens the solenoid valve 141 and puts the lubricating oil supply tank 139 in the crankcase 13. Lubricating oil flows in from.

Further, for example, the lower limit value Qc of the oil retention amount is set as the first lower limit value and the second lower limit value lower than the first lower limit value, and an alarm is issued when the oil retention amount reaches the first lower limit value. When the alarm is issued and the oil retention amount reaches the second lower limit value, the above operation may be executed to automatically replenish the lubricating oil.

[Other Embodiments]
(1) In the first embodiment, when the amount of oil decreases, only an alarm indicating the decrease in the amount of oil is issued, but the engine may be stopped. To stop the engine, for example, a communication path (not shown) that communicates with the compression space 6 and the inside of the crank case 13 and an on-off valve (not shown) that can open and close the flow path of the communication path are provided, and an operation execution unit is provided. 73 sends an open command to the on-off valve to change the on-off valve from the closed state to the open state, so that the working gas in the working space (expansion space 5 and compression space 6) is passed through the communication path to the buffer space 17b (crank). It is possible by moving it into the case 13). Further, for example, the lower limit value Qc of the oil retention amount is set as the first lower limit value and the second lower limit value lower than the first lower limit value, and an alarm is issued when the oil retention amount reaches the first lower limit value. The engine may be configured to stop when an alarm is issued and the oil retention amount reaches the second lower limit value.

(2) In the first and second embodiments described above, the Stirling engine 1 is arranged so that the displacer piston yoke 51 and the power piston yokes 52 and 53 reciprocate in the vertical direction, and the output take-out device 11 is located below the cylinder 2. The Stirling engine 1 is arranged so that the displacer piston yoke 51 and the power piston yokes 52 and 53 reciprocate in the horizontal direction, and the output take-out device 11 is provided on the side of the cylinder 2. May be good.

Further, in the first and second embodiments described above, the description is based on the β-type Stirling engine 1, but other types of Stirling engines such as α-type and γ-type may be used. Further, although the Stirling engine 1 is shown as an example of the engine, the engine is not limited to this, and any engine having a structure for storing lubricating oil in the crankcase may be used.

Although the embodiments of the present invention have been described above with reference to the drawings, it should be considered that the specific configuration is not limited to these embodiments. The scope of the present invention is shown not only by the description of the above-described embodiment but also by the scope of claims, and further includes all modifications within the meaning and scope equivalent to the scope of claims.

1 Sterling engine 3 Displacer piston 4 Power piston 12 Crankshaft 13 Crankcase 13a Lubricating oil storage 15 Motor generator 51 Displacer piston yoke 52 Power piston yoke 53 Power piston yoke 70 Control device 71 Oil amount detector 73 Operation execution unit 74 Motor Control unit 75 Oil amount correction unit 131 Inner cylinder 132 Side hole 133 1st communication hole 134 2nd communication hole 135 Lubricating oil path 137 Flow meter 138 Temperature sensor 139 Lubricating oil replenishment tank 141 Electromagnetic valve

Claims (5)

A reciprocating piston and
A crankshaft that can rotate by the reciprocating movement of the piston,
A connecting member that connects the piston and the crankshaft,
A crankcase that supports the crankshaft and has a lubricating oil storage portion that stores lubricating oil.
A first communication hole formed in the lubricating oil storage portion and communicating with the inside and outside of the crankcase,
A second communication hole formed at a position away from the lubricating oil storage portion and communicating with the inside and outside of the crankcase,
A lubricating oil path in which the first communication hole and the second communication hole are connected outside the crankcase and the lubricating oil flows in from the first communication hole due to the movement of the connecting member.
A flow rate measuring device that measures the flow rate of the lubricating oil that has flowed into the lubricating oil path, and
When the engine speed is equal to or higher than the predetermined speed, the amount of lubricating oil in the lubricating oil storage section is calculated based on the flow rate, and the oil amount detection unit capable of detecting that the amount of oil is equal to or lower than the predetermined amount. When,
When the engine speed is lower than the predetermined speed, the engine speed is controlled to be equal to or higher than the predetermined speed, and the oil amount detection unit increases the amount of lubricating oil in the lubricating oil storage unit to a predetermined amount. An engine including an operation execution unit that executes a predetermined operation when it is detected to be the following. An oil temperature measuring device that measures the temperature of the lubricating oil,
A claim that includes an oil amount correction unit that corrects the oil amount of the lubricating oil in the lubricating oil storage unit calculated by the oil amount detection unit according to the temperature of the lubricating oil measured by the oil temperature measuring device. Item 1. The engine according to item 1. A lubricating oil supply tank connected to the crankcase via a solenoid valve is provided.
When the operation executing unit detects that the amount of lubricating oil in the lubricating oil storage unit is equal to or less than a predetermined amount by the oil amount detecting unit, the operation executing unit opens the electromagnetic valve and puts the lubricating oil supply tank in the crankcase. The engine according to claim 1 or 2, wherein the lubricating oil is introduced from the engine. A tubular member which is an inner surface of the crankcase and is erected around the first communication hole and accommodates at least a part of the connecting member when the piston is located at the bottom dead center.
The engine according to any one of claims 1 to 3, further comprising at least one side hole formed on a side surface of the tubular member and communicating inside and outside the tubular member. A motor generator connected to one end side of the crankshaft is provided.
The method according to any one of claims 1 to 4, wherein when the engine speed is lower than the predetermined speed, the motor generator performs power running operation so that the engine speed becomes the predetermined speed. engine.

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