JP2010196502A - Supercharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a mechanical dynamic loss caused by friction between a rotor shaft and a bearing in a supercharger low load operation area, and to increase mechanical efficiency. <P>SOLUTION: In this supercharger 1, a supercharger turbine and the shaft portion 4 of a compressor, which are stored in a housing 5, are coupled to each other, the bearing 7 set on a bearing stand 6 in the housing 5 rotatably supports the shaft portion 4, and combustion air for an internal combustion engine is compressed by a compressor driven by the supercharger turbine and is supplied to a combustion chamber. The supercharger includes: a main lubricating oil system coupled to a main lubricating oil pump and supplying lubricating oil to the bearing 7; an oil sump 12 provided in the bottom of the bearing stand 6 and accumulating the lubricating oil falling after lubricating the bearing 7 by a predetermined amount; and an auxiliary lubricating oil system coupled to an auxiliary lubricating oil pump 20 and supplying the lubricating oil accumulated in the oil sump 12 to the bearing 7. The auxiliary lubricating oil pump 20 is operated in a low load operation area where the rotational speed of the shaft portion 4 is low and when temperature in the housing 5 is lower than a predetermined value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a supercharger applied to a large diesel engine for marine use or power generation.

  Conventionally, a supercharger that compresses combustion air of an internal combustion engine and forcibly sends high-density air into a combustion chamber is known, and is widely used in, for example, large diesel engines for ships and power generation. . In such a supercharger, a compressor for compressing combustion air and a turbocharger turbine serving as a drive source for the compressor are coaxial, housed in a housing, and rotate integrally. Note that the turbocharger turbine is driven by energy held by the exhaust gas of the internal combustion engine (see, for example, Patent Document 1).

JP 59-180198 A

  In the turbocharger disclosed in Patent Document 1, lubricating oil having a temperature of about 40 ° C. is supplied to a bearing that rotatably supports both ends of the rotor shaft regardless of the engine load. Yes. However, in a low-load operation region where the turbocharger rotation speed (more specifically, the rotation speed of the rotor shaft) is low (that is, the pressure of air sent (discharged) from the compressor (compressor) or the combustion of the internal combustion engine) When the pressure of the air supplied to the chamber is lower than about 0.2 MPa (2 bar) in absolute pressure), when the temperature of the lubricating oil is about 40 ° C., the influence of the viscosity of the lubricating oil increases, and the rotor shaft and The mechanical power loss due to the friction with the bearing is increased, the mechanical efficiency is decreased, the fuel consumption of the internal combustion engine is deteriorated, and the reliability of the internal combustion engine may be decreased. In general, it is effective to supply low-viscosity oil to reduce the mechanical loss of the bearing. However, it is necessary to provide a low-viscosity oil supply system exclusively for the supercharger, which increases costs. Increasing the temperature of the oil can reduce the viscosity. However, when the rotor shaft is operated at a high speed, the bearing temperature becomes too high and the reliability of the bearing may be reduced. Furthermore, oil supply with low viscosity makes it difficult to stably rotate the rotor shaft at high rotation, and therefore, oil with proper viscosity is usually selected.

  The present invention has been made in view of the above circumstances, and ensures mechanical reliability due to friction between a rotor shaft and a bearing in a low load operation region where the rotation speed is low while ensuring reliability in a high load operation region where the rotation speed is high. An object of the present invention is to provide a supercharger capable of reducing power loss and increasing mechanical efficiency.

The present invention employs the following means in order to solve the above problems.
A turbocharger according to the present invention is connected to a shaft portion of a turbocharger turbine and a compressor housed in a housing, and a bearing installed on a bearing stand in the housing rotatably supports the shaft portion, The compressor driven by the turbocharger turbine is a turbocharger that compresses combustion air of an internal combustion engine and supplies the combustion chamber to a combustion chamber, and is connected to a main lubricant pump to supply lubricant to the bearing. A main lubricating oil system, an oil reservoir that is provided at the bottom of the bearing stand and retains a predetermined amount of lubricating oil that falls after lubricating the bearing, and is connected to an auxiliary lubricating oil pump and stays in the oil reservoir. An auxiliary lubricating oil system for supplying the lubricating oil to the bearing, and the auxiliary lubrication is performed in a low load operation region where the rotational speed of the shaft portion is low and the temperature in the housing is equal to or lower than a predetermined value. The oil pump is operated .

According to the supercharger according to the present invention, the pressure of the air sent from the compressor or the pressure of the air supplied to the combustion chamber of the internal combustion engine is reduced even in the low load operation region where the rotational speed of the shaft portion is low. The absolute pressure is increased until the temperature of the lubricating oil reaches a predetermined value (for example, about 70 ° C.), for example, even when the pressure is lower than 0.2 MPa (2 bar). Since the effect of oil viscosity is reduced, mechanical power loss due to friction between the shaft portion and the bearing can be reduced, and mechanical efficiency can be improved.
Further, since the lubricating oil is warmed (heated) by friction between the shaft portion and the bearing, heating means such as a heater for warming (raising the temperature of the lubricating oil) can be made unnecessary. The energy loss consumed can be eliminated.

Furthermore, according to the supercharger according to the present invention, the rotational speed of the shaft portion is reduced, the pressure of the air sent from the compressor, or the pressure of the air supplied to the combustion chamber of the internal combustion engine is an absolute pressure, For example, when the pressure is lower than 0.2 MPa, the auxiliary lubricating oil pump is automatically started, and even when the main lubricating oil pump is stopped, the lubricating oil is supplied to the bearing by the auxiliary lubricating oil pump. It is possible.
As a result, for example, when the marine diesel engine is opened, when the main lubricating oil pump needs to be stopped to perform maintenance work, the supply of lubricating oil from the main lubricating oil system to the turbocharger is stopped. However, the lubricating oil can be supplied from the auxiliary lubricating oil system to the bearing of the supercharger. That is, even when the shaft portion of the turbocharger turbine rotates at a low speed due to air inflow or the like in the engine room, the lubricating oil can be supplied from the auxiliary lubricating oil system to the bearing. The occurrence of damage can be prevented or suppressed. In other words, when the diesel engine itself and / or the turbocharger is released and maintained, the turbocharger in which the shaft portion in the housing rotates at a low speed reliably prevents or suppresses the occurrence of bearing damage due to lack of lubricating oil. be able to.

  An internal combustion engine according to the present invention is equipped with a supercharger that can reduce mechanical power loss due to friction between a shaft portion and a bearing and can improve mechanical efficiency.

  According to the internal combustion engine of the present invention, the amount of air supplied to the combustion chamber increases, so that fuel efficiency and reliability can be improved.

According to the supercharger according to the present invention, it is possible to reduce mechanical power loss due to friction between the shaft portion and the bearing in the low load operation region where the rotational speed is low, and to improve the mechanical efficiency. Play.
In addition, according to the internal combustion engine equipped with the supercharger according to the present invention, there is an effect that fuel efficiency and reliability can be improved.

It is a block diagram which shows the outline | summary of a supercharger. It is sectional drawing (shaft part cross section of FIG. 1) of the principal part which shows one Embodiment of the supercharger which concerns on this invention.

Hereinafter, an embodiment of a supercharger according to the present invention will be described with reference to FIGS. 1 and 2.
A supercharger 1 shown in FIG. 1 is installed in an intake system of an internal combustion engine, compresses combustion air, and sucks and explodes an air-fuel mixture that exceeds the original intake amount of the internal combustion engine, thereby exceeding the apparent exhaust amount. A device for obtaining output.
A turbocharger 1 is connected to a turbocharger turbine 2 and a shaft portion (rotor shaft) 4 of a compressor 3, and is connected to a turbocharger rotor (coaxially connected supercharger turbine) housed in a housing 5 described later. 2 and the rotating body of the compressor 3) rotate together. The supercharger turbine 2 introduces exhaust gas discharged from the internal combustion engine, and rotates at high speed using the energy (temperature and pressure) of the exhaust gas. The supercharger turbine 2 serves as a drive source for rotating the coaxial compressor 3.

  The compressor 3 rotates using the turbocharger turbine 2 as a drive source, and sucks and compresses combustion air of the internal combustion engine. The combustion air compressed by the compressor 3 is supplied to the combustion chamber through the intake system of the internal combustion engine.

FIG. 1 is a configuration diagram showing an outline of the supercharger 1, and shows a cross section of a shaft portion 4 connecting the supercharger turbine 2 and the compressor 3 in FIG. 2.
In the illustrated supercharger 1, a shaft portion 4 is accommodated in a bearing stand 6 provided in a housing 5 and is disposed horizontally. The shaft portion 4 is rotatably supported by a bearing 7 installed on a bearing base 6 of the housing 5. That is, a bearing base 6 is provided at an intermediate portion between the supercharger turbine 2 and the compressor 3, and a bearing 7 installed on the bearing base 6 supports the shaft portion 4 in a freely rotatable manner.

A head tank 8 is provided above the bearing base 6 as a space for storing lubricating oil to be supplied to the bearing 7. The head tank 8 is connected to a main lubricating oil pipe 9 that is connected to a main lubricating oil pump (not shown) to form a main lubricating oil system. In the head tank 8, lubricating oil passages 10 and 11 for guiding the lubricating oil in the head tank 8 to the bearing 7 are formed. That is, when the supercharger 1 is operated, the main lubricating oil pump is also operated, so that the head tank 8 is filled with lubricating oil, and this lubricating oil has lubricating oil passages 10 having different opening positions. , 11 to be surely supplied to the bearing 7.
By the way, when the operation of the supercharger 1 is stopped, the operation of the main lubricating oil pump is also stopped. However, since the turbocharger rotor rotates by inertia for a while, it is necessary to lubricate the bearing 7 by effectively using the lubricating oil accumulated in the head tank 8 even after the main lubricating oil pump is stopped. Become. Therefore, when the lubricating oil passages 10 and 11 having different heights are provided and the remaining amount of the lubricating oil in the head tank 8 is large, the lubricating oil flows from the lubricating oil passage 10 having a high inlet height to all the bearings 7. When the remaining amount of the lubricating oil in the head tank 8 is small, the lubricating oil is supplied only from the lubricating oil passage 11 having a low inlet height to the bearing 7 on the supercharger turbine 2 side having a high temperature.

A space serving as an oil sump 12 is formed below the bearing stand 6 and the lubricating oil after lubricating the bearing 7 naturally falls, so that a predetermined amount can always be retained. Yes. The oil reservoir 12 is connected to a lubricating oil recovery pipe 13 for returning the lubricating oil to a lubricating oil tank (not shown) for supplying the lubricating oil to a main lubricating oil pump (not shown). The lubricating oil recovery pipe 13 is connected to a position where a predetermined oil level height is formed from the oil reservoir bottom surface 12 a in order to always retain a predetermined amount of lubricating oil in the oil reservoir 12. That is, since the oil reservoir 12 has a wall portion 12b having a predetermined height from the bottom surface 12a, the lubricating oil recovery pipe 13 is connected to the upper end portion of the wall portion 12b.
In the figure, reference numeral 14 denotes an outlet opening for dropping the lubricating oil from the bearing 7 to the oil reservoir 12, and reference numeral 15 denotes an air vent of the oil reservoir 12.

  The oil reservoir 12 is provided with an auxiliary lubricating oil pump 20 that is operated when the main lubricating oil pump is stopped. The auxiliary lubricating oil pump 20 is attached so as to substantially coincide with the bottom surface 12 a of the oil reservoir 12. An auxiliary lubricating oil pipe 21 that is connected to the auxiliary lubricating oil pump 20 and guides the lubricating oil in the oil reservoir 12 to the head tank 8 is provided. A check valve 22 is provided at an appropriate position of the auxiliary lubricating oil pipe 21 to prevent the lubricating oil from flowing back from the head tank 8 to the auxiliary lubricating oil pump 20 during operation of the main lubricating oil pump.

  A three-way valve 23 is provided in the auxiliary lubricating oil pipe 21 located on the downstream side of the check valve 22. The three-way valve 23 is, for example, an electric three-way valve whose flow path is switched by the control device 24, and the lubricating oil sent (discharged) from the auxiliary lubricating oil pump 20 passes through the auxiliary lubricating oil pipe 21. Then, it is led to the head tank 8 or led to the middle of the lubricating oil recovery pipe 13 via the lubricating oil pipe 25.

  A temperature sensor 26 that detects the temperature in the housing 5 is provided at an appropriate position (the top portion in the present embodiment) of the housing 5. The detection signal detected by the temperature sensor 26 is input to the control device 24 that controls the flow path of the three-way valve 23. That is, when the temperature in the housing 5 is 70 ° C. or lower, a flow path for leading the lubricating oil sent from the auxiliary lubricating oil pump 20 to the head tank 8 through the auxiliary lubricating oil pipe 21 is opened. The flow path leading to the lubricating oil recovery pipe 13 via the lubricating oil pipe 25 is closed. When the temperature in the housing 5 exceeds 70 ° C., a flow path for leading the lubricating oil sent from the auxiliary lubricating oil pump 20 to the lubricating oil recovery pipe 13 via the lubricating oil pipe 25 is opened. The flow path leading to the head tank 8 via the auxiliary lubricating oil pipe 21 is closed.

Then, the rotational speed of the supercharger 1 (more specifically, the rotational speed of the shaft portion 4) increases (increases), and the pressure of the air sent (discharged) from the compressor 3 or the combustion chamber of the internal combustion engine When the pressure of the supplied air reaches 0.2 MPa (2 bar) in absolute pressure, the auxiliary lubricating oil pump 20 is automatically stopped.
On the other hand, the rotational speed of the supercharger 1 is reduced (decreased), and the pressure of the air sent from the compressor 3 or the pressure of the air supplied to the combustion chamber of the internal combustion engine is less than 0.2 MPa in absolute pressure. When it becomes low, the auxiliary lubricating oil pump 20 is automatically started. At this time, when the temperature in the housing 5 is, for example, 70 ° C. or less, the flow path for guiding the lubricating oil sent from the auxiliary lubricating oil pump 20 to the head tank 8 via the auxiliary lubricating oil pipe 21. Is opened, and the flow path leading to the lubricating oil recovery pipe 13 through the lubricating oil pipe 25 is closed. Further, when the temperature in the housing 5 exceeds 70 ° C., for example, there is a flow path for guiding the lubricating oil sent from the auxiliary lubricating oil pump 20 to the lubricating oil recovery pipe 13 via the lubricating oil pipe 25. The flow path leading to the head tank 8 through the auxiliary lubricating oil pipe 21 is closed.

The pressure of the air sent from the compressor 3 or the pressure of the air supplied to the combustion chamber of the internal combustion engine is detected by a pressure sensor (not shown) such as a pressure switch, and the pressure detected by the pressure sensor. A detection signal such as a value is input to a control device (not shown) that controls ON / OFF of the auxiliary lubricating oil pump 20.
Further, a pressure gauge 32 and a thermometer 33 are provided at appropriate positions of the main lubricating oil pipe 9 as needed, so that the state of the lubricating oil flowing in the main lubricating oil pipe 9 can be visually determined.

  Thus, in the supercharger 1 described above, the turbocharger turbine 2 housed in the housing 5 and the shaft portion 4 of the compressor 3 are connected, and the bearing 7 installed on the bearing stand 6 in the housing 5 has the shaft portion. 4 is a device that rotatably supports 4 and a compressor 3 driven by a supercharger turbine 2 compresses combustion air of the internal combustion engine and supplies it to the combustion chamber. The supercharger 1 according to the present invention is connected to the main lubricating oil pump and supplies the lubricating oil to the bearing 7, and the supercharger 1 is provided at the bottom of the bearing stand 6 and lubricates the bearing 7, and then drops. The oil reservoir 12 for retaining a predetermined amount of lubricating oil and the lubricating oil that is connected to the auxiliary lubricating oil pump 20 and retained in the oil reservoir 12 is supplied to the bearing 7, or the lubricating oil is supplied via the lubricating oil pipe 25. An auxiliary lubricating oil system that escapes to the recovery pipe 13 is provided.

The main lubricating oil system in the illustrated supercharger 1 includes a main lubricating oil pipe 9 connected to a main lubricating oil pump, a head tank 8, lubricating oil passages 10, 11, a bearing 7, and an outlet opening 14. , A closed circuit lubricating oil circulation path formed by the oil reservoir 12, the lubricating oil recovery pipe 13, and the lubricating oil tank.
The auxiliary lubricating oil system in the illustrated supercharger 1 includes an auxiliary lubricating oil pump 20, an auxiliary lubricating oil pipe 21, a check valve 22, a three-way valve 23, a lubricating oil pipe 25, a head tank 8, This is a closed circuit lubricating oil circulation path formed by the lubricating oil flow path 11, the bearing 7, the outlet opening 14, and the oil reservoir 12.

According to the supercharger 1 according to the present embodiment, even in a low load operation region where the rotational speed of the supercharger 1 (more specifically, the rotational speed of the shaft portion 4) is low (that is, the air sent from the compressor 3). Or even if the pressure of the air supplied to the combustion chamber of the internal combustion engine is lower than 0.2 MPa (2 bar) in absolute pressure), the temperature of the lubricating oil is raised to, for example, 70 ° C., Since the viscosity of the lubricating oil is lowered and the influence of the viscosity of the lubricating oil is reduced, the mechanical power loss due to the friction between the shaft portion 4 and the bearing 7 can be reduced, and the mechanical efficiency can be improved.
Further, since the lubricating oil is heated (heated) by the friction between the shaft portion 4 and the bearing 7, heating means such as a heater for heating (heating) the lubricating oil can be dispensed with and heated. The energy loss consumed by the means can be eliminated.

  Furthermore, according to the supercharger 1 according to the present embodiment, the rotational speed of the supercharger 1 is reduced, and the pressure of air sent from the compressor 3 or the pressure of air supplied to the combustion chamber of the internal combustion engine. When the absolute pressure becomes lower than 0.2 MPa, the auxiliary lubricating oil pump 20 is automatically started, and even if the main lubricating oil pump stops, the auxiliary lubricating oil pump 20 is applied to the bearing 7. Lubricating oil can be supplied.

  As a result, for example, when the marine diesel engine is opened, when it is necessary to stop the main lubricating oil pump and perform maintenance or the like, the lubricating oil is supplied from the main lubricating oil system to the supercharger 1. Even if stopped, the lubricating oil can be supplied from the auxiliary lubricating oil system to the bearing 7 of the supercharger 1. That is, even when the rotor of the turbocharger turbine 2 rotates at a low speed due to air inflow or the like in the engine room, the lubricating oil can be supplied from the auxiliary lubricating oil system to the bearing 7. The occurrence of bearing damage can be prevented or suppressed. In other words, when the diesel engine itself and / or the turbocharger 1 is released and maintained, in the turbocharger 1 in which the turbocharger rotor in the housing 5 rotates at a low speed, it is ensured that bearing damage will occur due to lack of lubricating oil. Can be prevented or suppressed.

  And according to the internal combustion engine which mounts the supercharger 1 which concerns on this embodiment, since the air supply amount supplied to a combustion chamber will increase, a fuel consumption and reliability can be improved.

The supercharger 1 described above is not limited to a large marine diesel engine, and can be applied to various internal combustion engines including a diesel engine for power generation.
Further, the present invention is not limited to the above-described embodiment, and can be appropriately changed within a range not departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Supercharger 2 Supercharger turbine 3 Compressor 4 Shaft part 5 Housing 6 Bearing stand 7 Bearing 12 Oil reservoir 20 Auxiliary lubricating oil pump

Claims (2)

A shaft portion of a turbocharger turbine and a compressor housed in a housing is connected, and a bearing installed on a bearing stand in the housing rotatably supports the shaft portion and is driven by the turbocharger turbine. The compressor is a supercharger that compresses combustion air of an internal combustion engine and supplies the compressed air to a combustion chamber,
A main lubricating oil system connected to a main lubricating oil pump to supply lubricating oil to the bearing;
An oil sump that is provided at the bottom of the bearing stand and retains a predetermined amount of lubricating oil that falls after lubricating the bearing;
An auxiliary lubricating oil system connected to an auxiliary lubricating oil pump and supplying lubricating oil staying in the oil reservoir to the bearing;
The supercharger, wherein the auxiliary lubricating oil pump is operated when the shaft portion is in a low load operation region where the rotational speed is low and the temperature in the housing is equal to or lower than a predetermined value.   An internal combustion engine comprising the supercharger according to claim 1.

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