JP2004044542A - Lubrication apparatus for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain the load of a motor-driven oil pump and energy loss of the whole apparatus, in a lubrication apparatus for an internal combustion engine equipped with a mechanical oil pump and the motor-driven oil pump. <P>SOLUTION: This lubrication apparatus for the internal combustion engine 10 is equipped with the mechanical oil pump 21 which is drivingly-connected to an engine output shaft 11 so as to obtain driving force; and the motor-driven oil pump 23. The mechanical oil pump 21 supplies oil to an engine lubrication portion 14. The motor-driven oil pump 23 supplies oil to a variable valve mechanism 13 as working oil. In the motor-driven oil pump 23, the oil of which the pressure is raised once by the mechanical oil pump 21 when a relief valve 22 is opened is supplied through a relief passage 24. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a lubricating device for an internal combustion engine that includes a mechanical oil pump and an electric oil pump, and supplies oil from the respective pumps to various parts of the internal combustion engine.
[0002]
[Prior art]
Normally, a lubricating device for an internal combustion engine includes a mechanical oil pump that is driven with rotation of an engine output shaft, and supplies oil to various parts of the engine from the pump. Further, the oil supplied by such a lubricating device may not only have a function as a lubricating oil as its original purpose, but also have a function to supply a working oil pressure to various actuators of an internal combustion engine, that is, a function as a working oil. is there. A typical example of such an actuator is a variable valve mechanism that has recently been mounted on many internal combustion engines.
[0003]
Incidentally, in such an actuator or the like, it may be necessary to supply a large amount of oil at a high pressure depending on the operation state. However, if oil is supplied to an actuator or the like in response to such a demand, excessive oil will be supplied to a normal lubricating portion. Such excessive oil supply contributes to an increase in the driving resistance of the internal combustion engine. Naturally, the size of the mechanical oil pump is unavoidable in order to secure the oil supply capacity that meets such demands.
[0004]
Therefore, in Japanese Patent Application Laid-Open No. 7-71216, an electric oil pump is provided separately from such a mechanical oil pump. When it is necessary to supply oil exceeding the supply capacity of the mechanical oil pump, the electric oil pump is operated to make up for the insufficient oil supply.
[0005]
[Problems to be solved by the invention]
According to this conventional device, it is not necessary to increase the discharge capacity of the engine type oil pump more than necessary, and the electric oil pump only needs to deal with the shortage of oil supply generated in the engine type oil pump. For this reason, the power consumption can be suppressed as compared with the configuration using only the electric oil pump.
[0006]
However, in this conventional device, for example, when oil is supplied to an actuator or the like by an electric oil pump, it is necessary to increase the pressure of low-pressure oil stored in an oil pan until the actuator can be operated. There is. For this reason, the load of the electric oil pump itself is still large, and there is naturally a limit in reducing the size and reducing the power consumption, and there is still room for improvement in this respect.
[0007]
The present invention has been made in view of such conventional circumstances, and has as its object to reduce the load on an electric oil pump in a lubrication system for an internal combustion engine having a mechanical oil pump and an electric oil pump. Another object of the present invention is to suppress energy loss of the entire apparatus.
[0008]
[Means for Solving the Problems]
The configuration for achieving the above object and the operation and effect thereof will be described below.
According to the first aspect of the invention, there are provided a mechanical oil pump which is drivingly connected to an output shaft of the internal combustion engine to obtain a driving force, and an electric oil pump, and supplies oil to each part of the internal combustion engine from each of these oil pumps. In the lubrication system for an internal combustion engine, the electric oil pump is configured to be supplied with high-pressure oil that is relieved after the mechanical oil pump is pressurized.
[0009]
According to this configuration, the oil once pressurized by the mechanical oil pump is supplied to the electric oil pump. For this reason, it is possible to reduce the pressure increase of the oil by the electric oil pump to reduce the load. In addition, since the energy of the oil which has been conventionally pressurized by the mechanical oil pump but has been returned to the oil pan as it is can be effectively used, the energy loss of the entire apparatus can be suppressed low. Become like
[0010]
According to a second aspect of the present invention, in the lubricating apparatus for an internal combustion engine according to the first aspect, the electric oil pump is provided with a passage through which high-pressure oil relieved from the mechanical oil pump is supplied to the electric oil pump through the passage. It is stated that a flow control valve for adjusting the amount of oil supplied to the oil pump is provided.
[0011]
According to this configuration, by adjusting the amount of oil supplied to the electric oil pump by the flow control valve, it becomes possible to supply the required amount of oil to the electric oil pump. The load on the oil pump can be further reduced.
[0012]
According to a third aspect of the present invention, in the lubricating device for an internal combustion engine according to the first or second aspect, the electric oil pump uses oil as hydraulic oil and supplies the oil to an actuator that operates based on the oil pressure. .
[0013]
Further, in particular, the invention according to claim 4 assumes that such an actuator is a variable valve mechanism of an internal combustion engine.
Generally, in an actuator such as a variable valve mechanism of an internal combustion engine, it is necessary to supply high-pressure oil as hydraulic oil. However, since the mechanical oil pump is configured to be driven and connected to the output shaft of the internal combustion engine to obtain a driving force, when the engine rotation speed is low, the discharge amount is reduced, and the oil supply capacity is reduced. Therefore, if the demand for such an actuator is to be dealt with only by the mechanical oil pump, it is inevitable that the mechanical oil pump becomes larger.
[0014]
In view of this point, the invention according to claim 3 or 4 is configured to separately supply oil to the actuator from an electric oil pump. For this reason, a required amount of oil can be supplied to the actuator without increasing the size of the mechanical oil pump even when the engine is running at a low speed.
[0015]
According to a fifth aspect of the present invention, in the lubricating device for an internal combustion engine according to the third or fourth aspect, a discharge amount control means for controlling a discharge amount of the electric oil pump according to an operation state of the actuator is further provided. ing.
[0016]
According to a sixth aspect of the present invention, in the lubricating device for an internal combustion engine according to any of the third to fifth aspects, the flow control valve according to the second aspect and the flow control valve according to an operation state of the actuator. And an opening control means for controlling the opening.
[0017]
According to the fifth or sixth aspect of the present invention, the load of the electric oil pump is adjusted by controlling the discharge amount of the electric oil pump and the opening of the flow control valve in accordance with the operation state of the actuator. And the load can be further reduced.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIG.
[0019]
FIG. 1 schematically shows a configuration of a lubrication device according to the present embodiment and an internal combustion engine 10 to which the lubrication device is applied.
As shown in FIG. 1, the lubricating device for the internal combustion engine 10 includes an oil pan 20 that stores oil, and a mechanical oil pump 21 that sucks oil from the oil pan 20 and supplies the oil to an engine lubrication part 14. Have. This mechanical oil pump is drivingly connected to an output shaft 11 of the internal combustion engine 10 and operates using the rotational force of the output shaft 11 as a driving force. Therefore, the oil discharge capacity depends on the engine rotation speed, and increases as the rotation speed increases. Examples of the engine lubrication portion include a sliding portion such as the output shaft 11, a connecting rod (not shown), a cam journal, a cam nose, and a valve lifter.
[0020]
The mechanical oil pump 21 is connected to an electric oil pump 23 via a relief passage 24. A relief valve 22 is provided in the middle of the relief passage 24. The relief valve 22 is opened when the discharge pressure of the mechanical oil pump 21 becomes equal to or higher than a predetermined pressure PL as the engine speed increases. The valve is released to release the oil to the electric oil pump 23 side. Therefore, the oil once pressurized by the mechanical oil pump 21 is supplied to the electric oil pump 23 through the relief passage 24.
[0021]
The electric oil pump 23 is a pump that operates by receiving power supply from a battery (not shown), and can ensure its discharge capacity without depending on the engine speed. The electric oil pump 23 is connected via a drive circuit 42 to an electronic control unit 40 that executes various controls of the internal combustion engine 10. The electronic control unit 40 controls the discharge amount of the electric oil pump 23 by outputting a drive signal to the drive circuit 42.
[0022]
Further, the internal combustion engine 10 includes a variable valve mechanism 13. The variable valve mechanism 13 changes valve timing and valve lift of an intake valve or an exhaust valve (both not shown) by operating based on the oil pressure of oil supplied from a lubricating device. The electronic control unit 40 takes in detection signals of various sensors such as an engine rotation speed sensor 51, an intake air amount sensor 52, a water temperature sensor 53 for detecting the temperature of engine cooling water, and the like, and based on the engine operating state, the variable valve mechanism 13 Control the operating state of the
[0023]
The variable valve mechanism 13 is connected to the electric oil pump 23 through a first oil passage 31 and is connected to the engine lubrication part 14 through a second oil passage 32. Therefore, the variable valve mechanism 13 is supplied with a part of the oil used for lubricating the engine lubrication part 14 through the second oil passage 32 and is electrically driven through the first oil passage 31. The oil pressurized by the oil pump 23 is supplied.
[0024]
The electronic control unit 40 sets the discharge amount of the electric oil pump 23 in the engine operating state so that the required operating pressure is secured in the variable valve mechanism 13 in addition to the control of the variable valve mechanism 13 described above. Control based on.
[0025]
Specifically, when it is determined based on the engine operating state that the operation amount of the variable valve mechanism 13 is large and therefore a large amount of oil at high pressure is required in the variable valve mechanism 13, The discharge amount of the pump 23 is increased. On the other hand, when it is determined based on the engine operating state that the operation amount of the variable valve mechanism 13 is small and the required amount of oil is small, the discharge amount of the electric oil pump 23 is reduced.
[0026]
Here, in the case of an actuator such as the variable valve mechanism 13, an operating pressure that is normally higher than the discharge pressure of the mechanical oil pump 21 when oil is supplied only to the engine lubrication portion 14 is required. . That is, a magnitude relationship of (PA> PL) is always established between the operating pressure PA and the predetermined pressure PL.
[0027]
Therefore, if the discharge pressure PL of the mechanical oil pump 21 is set in accordance with the operating pressure of the variable valve mechanism 13, excessive oil is supplied to the other engine lubrication parts 14, and the mechanical This increases the size of the oil pump 21 and further increases the energy loss of the entire lubricating device.
[0028]
Therefore, in the present embodiment, in addition to a part of the oil supplied to the engine lubrication part 14, the oil is further supplied from the electric oil pump 23 to the variable valve mechanism 13. According to the present embodiment in which the oil is separately supplied from the electric oil pump 23 to the variable valve mechanism 13 requiring a large amount of oil at a high pressure, the following operation and effect can be obtained. Can be.
[0029]
The oil once pressurized by the mechanical oil pump 21 is supplied to the electric oil pump 23. For this reason, it is possible to reduce the pressure increase of the oil by the electric oil pump 23 to reduce the load. Further, since the energy of the oil that has been conventionally pressurized by the mechanical oil pump 21 but has been returned to the oil pan 20 as it is can be effectively used, the energy loss of the entire lubricating device can be suppressed. become.
[0030]
The oil is separately supplied to the variable valve mechanism 13 from the electric oil pump 23. For this reason, the required amount of oil can be supplied to the variable valve mechanism 13 even when the engine is running at a low speed without increasing the size of the mechanical oil pump 21.
[0031]
Further, since the discharge amount of the electric oil pump 23 is controlled according to the operation state of the variable valve mechanism 13, the load on the electric oil pump 23 can be adjusted according to the operation state. Thus, the load can be further reduced.
[0032]
[Second embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to FIG. 2 focusing on differences from the first embodiment.
[0033]
In the first embodiment, all the oil relieved through the relief passage 24 is supplied to the electric oil pump 23, but in the present embodiment, the relief valve 22 is replaced by a flow control valve 25 instead of the relief valve 22. Is provided. Further, a return passage 26 is connected to the flow control valve 25. Accordingly, in accordance with the opening degree of the flow control valve 25, a necessary amount of oil is supplied to the electric oil pump 23 out of the oil flowing through the relief passage 24, while the excess oil is supplied through the return passage 26 through the return passage 26. It is returned to the pan 20.
[0034]
The flow control valve 25 is connected to the electronic control device 40 via the drive circuit 43. The electronic control device 40 adjusts the opening degree of the flow control valve 25 so that the oil required for the variable valve mechanism 13 is supplied to the electric oil pump 23 instead of controlling the discharge amount of the electric oil pump 23. Control is performed based on the engine operating state.
[0035]
Specifically, when it is determined based on the engine operating state that the operation amount of the variable valve mechanism 13 is large and therefore a large amount of oil at a high pressure is required in the variable valve mechanism 13, the flow control valve By increasing the opening degree of 25, the amount of oil supplied to the electric oil pump 23 is increased. On the other hand, when it is determined based on the engine operating state that the operation amount of the variable valve mechanism 13 is small and the required amount of oil is small, the opening degree of the flow control valve 25 is reduced, so that the electric oil pump 23 Reduce the amount of oil supplied to the The surplus amount of oil when the amount of oil supplied to the electric oil pump 23 is reduced in this way is returned from the flow control valve 25 to the oil pan 20 via the return passage 26.
[0036]
According to the above-described embodiment, the following effects can be obtained.
According to the present embodiment, the required amount of oil can be supplied to the electric oil pump 23 by adjusting the amount of oil supplied to the electric oil pump 23 by the flow control valve. The load on the oil pump 23 can be further reduced.
[0037]
Also, since the amount of oil supplied to the electric oil pump 23 via the flow control valve 25 is controlled according to the operation state of the variable valve mechanism 13, the electric type is controlled according to the operation state. The load on the oil pump can be adjusted, and the load can be further reduced.
[0038]
The configuration of the embodiment described above can be changed as follows.
In the above-described embodiment, the variable valve mechanism 13 has been described as an example of the oil supply portion by the electric oil pump 23. However, for example, the oil passage to the engine lubrication portion 14 to the same portion will be described. It may be configured to supply oil from the electric oil pump 23 to a portion having a large resistance.
[0039]
In the above embodiment, only the oil pressurized by the mechanical oil pump 21 is supplied to the electric oil pump 23, but the oil pan 20 also supplies the electric oil pump 23 Oil may be supplied. When the engine rotation speed is extremely low and the mechanical oil pump 21 does not discharge enough oil to operate the variable valve mechanism 13, such as when starting the engine, the oil in the oil pan 20 is removed from the electric oil pump 23. May be supplied to the variable valve mechanism 13.
[0040]
In the above embodiments, while the oil is supplied from the electric oil pump 23 to the variable valve mechanism 13 via the first oil passage 31, the oil is also supplied from the engine lubrication part 14 via the second oil passage 32. Oil is supplied to the variable valve mechanism 13 in an auxiliary manner. On the other hand, oil may be supplied to the variable valve mechanism 13 only from the electric oil pump 23 via the first oil passage 31.
[0041]
In the above embodiments, the variable valve mechanism 13 is shown as an example of an actuator to which oil is supplied from the electric oil pump 23, but the actuator is not limited to this. In short, the same operation and effect as those of the above embodiment can be obtained if the actuator requires a larger amount of oil at a higher pressure than the supply of oil to a normal lubrication part.
[0042]
Also, as the variable valve mechanism 13, a mechanism that changes only the valve timing and a mechanism that changes only the valve lift may be adopted in addition to the mechanism that changes both the valve timing and the valve lift.
[0043]
In the above embodiments, part of the oil used for lubricating the engine lubrication part 14 is supplied to the variable valve mechanism 13 through the second oil passage 32, but this is omitted, and the variable valve mechanism 13 is omitted. Oil may be supplied to the mechanism 13 only from the electric oil pump 23 through the first oil passage 31.
[0044]
In the second embodiment, the opening of the flow control valve 25 is controlled by the electronic control unit 40. However, the discharge amount of the electric oil pump 23 may be controlled in accordance with this.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram illustrating an outline of a lubrication device for an internal combustion engine according to a first embodiment.
FIG. 2 is a schematic configuration diagram showing an outline of a lubrication device for an internal combustion engine according to a second embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Output shaft, 13 ... Variable valve mechanism, 14 ... Engine lubrication part, 20 ... Oil pan, 21 ... Mechanical oil pump, 22 ... Relief valve, 23 ... Electric oil pump, 24 ... Relief Passages, 25 flow control valves, 26 return passages, 31 first oil passages, 32 second oil passages, 40 electronic control units (discharge amount control means, opening degree control means), 42, 43 ... Drive circuit, 51: engine speed sensor, 52: intake air amount sensor, 53: water temperature sensor.

Claims (6)

A mechanical oil pump that is driven and connected to an output shaft of the internal combustion engine to obtain a driving force, and an electric oil pump.
A lubricating device for an internal combustion engine, wherein the electric oil pump is configured to be supplied with high-pressure oil relieved after pressurization of the mechanical oil pump. 2. A flow control valve for metering oil supplied to the electric oil pump through the passage for supplying high-pressure oil relieved from the mechanical oil pump to the electric oil pump. A lubricating device for an internal combustion engine as described in the above. 3. The lubricating device for an internal combustion engine according to claim 1, wherein the electric oil pump uses oil as hydraulic oil and supplies the oil to an actuator that operates based on the hydraulic pressure. The lubricating device for an internal combustion engine according to claim 3, wherein the actuator is a variable valve mechanism of the internal combustion engine. The lubricating device for an internal combustion engine according to claim 3 or 4, further comprising a discharge amount control unit that controls a discharge amount of the electric oil pump in accordance with an operation state of the actuator. A flow control valve according to claim 2,
The lubricating device for an internal combustion engine according to any one of claims 3 to 5, further comprising an opening control unit configured to control an opening of the flow control valve in accordance with an operation state of the actuator.

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