JP3023803B2 - Oil supply device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve operating characteristic between an engine valve and a crankshaft supported on a cylinder head so as to be capable of opening and closing, the operating characteristic of the engine valve being changeable in response to a change in oil pressure in a hydraulic chamber. The present invention relates to a refueling device in an internal combustion engine provided with a valve train in which a change means is provided.

[0002]

2. Description of the Related Art Conventionally, an internal combustion engine equipped with such a valve train is already known, for example, from JP-A-61-229912 and JP-A-61-275516. An oil pump for supplying hydraulic oil to the hydraulic chamber of the valve operating characteristic changing means draws hydraulic oil from an oil pan of the engine body. However, since the oil pump is generally installed at the lower part of the engine body, the distance between the oil pump and the hydraulic chamber of the cylinder head, that is, the valve operating characteristic changing means provided at the upper part of the engine body, is reduced. Relatively long, so that the oil supply to the hydraulic chamber when the engine is started tends to be delayed.

Accordingly, the present applicant has arranged on a cylinder head a dedicated oil pump for head connected to a hydraulic chamber of a valve operating characteristic changing means and each lubricating portion of a valve operating system. (Japanese Patent Application No. 2-47056) has already proposed a lubricating apparatus for pumping hydraulic oil from an oil bath provided in the company.

[0004]

However, in the above-mentioned proposed technique, an oil supply system in which an oil pump for pumping oil from an oil pan at a lower portion of the engine body is connected to each hydraulic oil consuming portion at a lower portion of the engine body, and an oil bath. An oil pump formed by connecting a head dedicated oil pump for pumping oil from the hydraulic chamber of the valve operating characteristic changing means and each lubricating portion of the valve operating system is provided independently of each other, and an oil pan and an oil bath are provided. Are not communicated with each other, maintenance such as oil change and replenishment must be performed independently in both oil supply systems, and maintenance work is troublesome. The head-only oil pump is linked to and connected to the crankshaft of the engine, and has a large discharge amount as the engine speed increases. Thus, the valve operating characteristic changing means is, for example, of a type in which the valve operating piston is pressed and driven by the hydraulic pressure of the hydraulic chamber and the timing of releasing the hydraulic pressure of the hydraulic chamber is controlled to change the operating condition of the engine valve. Therefore, a relatively large amount of oil is required at the time of engine start and idling and at low engine speeds, and not so much oil is needed at high engine speeds. As the engine speed increases, more oil is required. As described above, when the oil dedicated to the head is supplied from the head dedicated oil pump to the portions having different required oil amount characteristics with respect to the engine speed, the capacity of the dedicated head oil pump is determined based on the required oil amount at the time of low speed rotation of the engine. Since the engine must be driven, the capacity of the head dedicated oil pump becomes excessive when the engine rotates at high speed, and the friction loss increases.

The present invention has been made in view of the above circumstances, and provides an oil supply device for an internal combustion engine that facilitates maintenance such as oil replacement and replenishment, and that can reduce friction loss during high-speed rotation of the engine. The purpose is to:

[0006]

According to the first aspect of the present invention , there is provided a first oil pump for pumping hydraulic oil from an oil pan provided at a lower portion of an engine body. A lubricating passage is connected to the lubricating passage, and a branching lubricating passage for lubricating the valve system, which communicates with each lubricating portion of the valve operating system including the valve operating camshaft connected to the crankshaft, is branched from the lubricating passage. An oil bath capable of receiving the oil leaked from each lubricating portion of the valve system and allowing the excess oil to overflow into the oil pan is provided, and a second oil pump for pumping hydraulic oil from the oil bath is provided with the valve operating valve. It is connected to the hydraulic chamber of the characteristic changing means , and
A passage leading directly to Irbus is connected.

[0007]

According to the second aspect of the present invention , the engine body
Pumping hydraulic oil from the oil pan provided at the bottom
1 Oil pump is connected to oil supply passage leading to hydraulic oil consumption section
Of the valve train including the valve train camshaft connected to the crankshaft.
A branch oil passage for valve system lubrication leading to the lubrication section
The cylinder head is divided into lubricating parts of the valve train.
Oil that leaks from the
An oil bath that allows excess oil to overflow is provided in the oil
The second oil pump that pumps hydraulic oil from the
An oil supply port connected to the hydraulic chamber of the operating characteristic changing means and provided in a head cover connected to the cylinder head or an introduction port communicating with the oil supply port is disposed immediately above the oil bath.

[0009]

1 to 5 show an embodiment of the present invention. FIG. 1 is a diagram of a refueling system of an internal combustion engine, and FIG. 2 is a valve operation. FIG. 3 is a vertical sectional view showing the configuration of the characteristic changing means, and FIG.
FIG. 4 is a sectional view of the cylinder head taken along the line 3, FIG. 4 is an operating characteristic diagram of the engine valve, and FIG.

[0010] First, in FIG. 1, the engine body E, and a lubricating oil supply system O _L refueling system for a valve operating characteristic changing means O _V is disposed. Thus the lubricating oil supply system O _L and the working oil from the oil pan 1 is disposed in the lower portion of the engine body E to the discharge port of the pumping gel first oil pump P, the oil supply passage 5 comprises a filter 4 relief A branch oil passage 6, which is connected through the valve 2 and branches from the oil supply passage 5, is provided at a lower portion of the engine body E with a crank journal portion 8 and a cooling jet 9.
, Etc., and a plurality of lubricating portions, ie, a cam journal portion 12 and a cam shower portion 13 in a valve train provided in a cylinder head 11 constituting an upper portion of the engine body E. , Etc., are branched from the oil supply passage 5. In addition, an orifice 10 is provided in the middle of the valve system lubrication branch oil passage 7.

The cylinder head 11 is provided with an oil bath 14 for receiving oil leaked from a plurality of lubricating portions in the valve train, that is, the cam journal portion 12 and the cam shower portions 13... A passage 15 directly communicating with 14 is connected to the valve system lubrication branch oil passage 7, and an orifice 16 is interposed in the passage 15.
Therefore, a part of the oil discharged from the oil pump P during the operation of the engine is supplied to the orifice 10, 1.
It is squeezed at 6 and always supplied.

[0012] valve operating characteristic changing means for refueling system O _V is ejection of the second oil pump P _C disposed in the cylinder head 11 Beku pumping gels hydraulic oil from the oil bath 14 provided in the cylinder head 11 At the outlet, a dedicated oil supply passage 19 having a filter 17 and a pressure regulating valve 18 is provided with a relief valve 20.
, And the exclusive oil supply passage 19 is connected to the valve operating characteristic changing means 21.

The valve operating characteristic changing means 21 can change the operating characteristics of the engine valve according to the operating state of the engine.
Next, the configuration of a portion related to the valve operating characteristic changing means 21 will be described with reference to FIGS.

The cylinder head 11 is provided with an intake valve port 23 which is opened at the top of a combustion chamber 22 formed between the cylinder head 11 and a cylinder block (not shown) through an intake port 24. An intake valve V as an openable and closable engine valve is disposed to be vertically movable. A flange 25 is provided at an upper end of the intake valve V, and a valve spring 26 is contracted between the flange 25 and the cylinder head 11. Thus, the intake valve V is urged upward, that is, in the valve closing direction by the spring force of the valve spring 26.

On the other hand, a valve operating cam shaft 27 is rotatably disposed above the cylinder head 11, and a pulley 33 provided at one end of the valve operating cam shaft 27 is connected to a pulley 33 via an endless belt (not shown). Power from the crankshaft is transmitted.
The second oil pump P _C is coupled to the other end of the valve operating cam shaft 27 is attached to the cylinder head 11. The valve cam shaft 27 is integrally provided with an intake valve cam 28 corresponding to the intake valve V of each cylinder and an exhaust valve cam 29 corresponding to an exhaust valve (not shown) of each cylinder. The rotation operation of each intake valve cam 28 is transmitted to each intake valve V via the valve operation characteristic changing means 21, and the rotation operation of each exhaust valve cam 29 is slidably contacted with the rocker arm 30. To each exhaust valve.

The valve operating characteristic changing means 21 includes: a transmission mechanism 31 interposed between the intake valve V and the intake valve cam 28;
A hydraulic circuit 32 connected to a hydraulic chamber 41 in the transmission mechanism 31.

The transmission mechanism 31 includes a first cylinder body 35 fixed to a support block 34 fixed to the upper portion of the cylinder head 11 coaxially with the intake valve V; A valve driving piston 37 slidably fitted to a lower portion of the first cylinder body 35 by defining a damper chamber 36 between the valve driving piston 37 and the intake side valve actuating cam 28.
A lifter 39 slidably fitted to the support block 34 while slidingly contacting the intake side valve operating cam 28, and an upper end of the lifter 39. A cam driven piston 40 is provided which is in contact with the second cylinder body 38, defines a hydraulic chamber 41 between the second cylinder body 38, and is slidably fitted to a lower portion of the second cylinder body 38.

On the inner surface of the first cylinder body 35, there is provided an annular recess 44 which is always in communication with the hydraulic chamber 41. The annular recess 44 is provided with an intake valve V, that is, a valve driving piston 37.
Is formed so that the hydraulic chamber 41 communicates with the damper chamber 36 when the valve is operated in the valve opening direction by a predetermined amount from the fully closed position. In addition, the valve drive piston 37 is provided with a check valve 42 that allows only the flow of hydraulic oil from the annular recess 44 communicating with the hydraulic chamber 41 to the damper chamber 36, and an orifice 43 that communicates the annular recess 44 with the damper chamber 36. Can be

In such a transmission mechanism 31, when the hydraulic pressure in the hydraulic chamber 41 is not released, the fully closed state of the intake valve V is in the state shown in FIG. Accordingly, when the cam driven piston 40 is pushed upward, the hydraulic pressure generated in the hydraulic chamber 41 changes to the check valve 4.
2 and the orifice 43 are guided to the damper chamber 36, and the hydraulic pressure in the damper chamber 36 causes the valve driving piston 37
Is pushed down. Thus, during the downward sliding of the valve drive piston 37, the hydraulic chamber 41 communicates directly with the damper chamber 36 via the annular recess 44, whereby the amount of oil flowing into the damper chamber 36 increases, and The drive piston 37 is pushed further downward, and the intake valve V opens against the spring force of the valve spring 26.

When the pressing force of the intake valve cam 28 is released after the intake valve V is fully opened, the intake valve V is driven upward, that is, in the valve closing direction by the spring force of the valve spring 26. The valve drive piston 37 is also pushed upward by the closing operation of the intake valve V, and the oil in the damper chamber 36 is released from the hydraulic chamber 4
Returned to 1. Thus, the direct communication between the annular recess 44 and the damper chamber 36 is released during the closing operation of the intake valve V, and the orifice 4 between the damper chamber 36 and the annular recess 44 is released.
When 3 is interposed, the amount of oil returned from the damper chamber 36 to the annular recess 44, that is, the hydraulic chamber 41 is limited.
For this reason, the upward moving speed of the intake valve V, that is, the valve closing speed is relaxed during the valve closing operation, and the intake valve V is seated gently, so that the impact at the time of seating is reduced.

The support block 34 is provided with a lift sensor S for detecting the upper end of the intake valve V when the intake valve V is completely closed.

When the hydraulic pressure in the hydraulic chamber 41 of the transmission mechanism 31 is released during the opening of the intake valve V, the hydraulic chamber 4 is released.
1 loses the transmission function of overcoming the spring force of the valve spring 26 and continuing to keep the intake valve V open. The valve V starts the valve closing operation by the resilient force of the valve spring 26 from the release of the hydraulic pressure, and the volume of the hydraulic chamber 41 is reduced.

The hydraulic circuit 32 controls the release of the hydraulic pressure from the hydraulic chamber 41 and the supply of hydraulic oil to the hydraulic chamber 41. The hydraulic circuit 32 includes a hydraulic release valve 45 and an accumulator 46.
, A one-way valve 47 and a check valve 48 and are disposed on the support block 34.

The hydraulic release valve 45 is provided between an oil passage 49 formed in the support block 34 in communication with the hydraulic chamber 41 and an oil passage 50 formed in the support block 34 while communicating with the accumulator 46. It is a solenoid valve interposed. One-way valve 4
7 is disposed on the support block 34 between the oil passage 50 and the oil passage 49 so as to bypass the oil pressure release valve 45, and the oil pressure in the oil passage 50 is set to be higher than the oil pressure in the oil passage 49. When it becomes larger, the valve is opened to allow only the flow of oil from the accumulator 46 to the oil passage 49, that is, the hydraulic chamber 41. The check valve 48 includes an intermediate portion between the accumulator 46 and the one-way valve 47, that is, an oil passage 50,
It is interposed between the dedicated oil supply passage 19 and allows only the flow of hydraulic oil from the dedicated oil supply passage 19 to the oil passage 50 side.

When the hydraulic pressure in the hydraulic chamber 41 is released by the hydraulic release valve 45 during the opening operation of the intake valve V,
By the start of the next valve opening operation, the hydraulic pressure of the accumulator 46 is returned to the hydraulic chamber 41 via the one-way valve 47, and the shortage is supplied to the hydraulic chamber 41 via the check valve 48. Thus, the hydraulic pressure acting on the oil passage 50 via the check valve 48 includes the lower limit pressure, which is the valve opening pressure of the one-way valve 47, and the accumulator 46.
It is necessary to be between the upper limit pressure, which is the pressure accumulation start pressure, and the oil pressure is adjusted by the pressure adjusting valve 18 so as to fall within such a range.

With particular attention to FIG. 3, the oil bath 14
Cam journal section 12 and cam shower section 13 ...
Oil leaked from the lubricating portion in the valve system and the like, and are those provided in the cylinder head 11 so as to a certain amount storing oil supplied from the passage 15, the suction tube connected to the second oil pump P _C 51 is protruded into the oil bath 14, and a strainer 52 is provided at the tip of the suction pipe 51. The cylinder head 11 has an oil bath 1
A plurality of overflow pipes 53 for returning excess oil from the oil pan 4 to the oil pan 1 are provided. Further, the cylinder head 11
A plug 54 for extracting oil from the oil bath 14 is screwed to a lower portion of the oil bath 14.

A head cover 55 is attached to an upper portion of the cylinder head 11 so as to cover a valve operating system and the like provided on the cylinder head 11. The head cover 55 is located immediately above the oil bath 14. Thus, the oil supply port 56 is provided, and the oil supply port 56 is closed by the oil cap 57 so as to be openable and closable.

Next, the operation of this embodiment will be described. In the valve operating characteristic changing means 21, when the hydraulic release valve 45 is opened during the opening operation of the intake valve V, the hydraulic chamber 41 is opened.
Is released to the accumulator 46,
By controlling the valve opening timing of the hydraulic release valve 45, that is, the hydraulic release timing, the opening / closing operation characteristics of the intake valve V can be changed. That is, as shown in FIG. 4, the lift amount and the valve closing timing of the intake valve V can be steplessly changed by controlling the hydraulic pressure release timing. As the engine load increases, the operating characteristic of the intake valve V becomes a curve a. → b → c → d →
It changes from e to f.

Further second oil pump P _C is intended to be disposed hydraulic oil to the cylinder head 11 Beku pumping gel from the oil bath 14 provided in the cylinder head 11,
Valve operating characteristic changing means can be relatively short distance between the hydraulic chamber 41 of the 21 and the second oil pump P _C, therefore, at the time of start of the engine, the oil supply to the hydraulic chamber 41 of the valve operating characteristic changing means 21 This can be performed promptly to improve responsiveness.

The amount of oil required by the valve operating characteristic changing means 21 varies according to the engine load as shown in FIG. That is, in the low load region _RL , as shown in FIG. 4, the oil release time of the hydraulic chamber 41 is advanced to shorten the valve lift amount and the valve closing time is advanced, so that the required oil amount is increased. At the time of starting, the required oil amount increases. Further, as the engine load increases, the required oil amount decreases due to the delay of the hydraulic pressure release timing. In the high load region _RH , when the intake valve V is in the fully closed state, cooling of the hydraulic oil and fresh Since only the hydraulic oil in the hydraulic chamber 41 is drained in order to exchange the hydraulic oil with another hydraulic oil, only a constant and small amount of hydraulic oil is required, and the required oil amount is minimized.

[0031] This amount of oil required in the valve operating characteristic changing means 21 so as to vary in accordance with the engine load, the second oil pump P _C is of only the valve operating characteristic changing means 21, other lubrication The pump capacity can be set independently of the above.
Therefore, even if you set the discharge amount of the second oil pump P _C in accordance with the required oil amount of the valve operating characteristic changing means 21 corresponding to the operating state of the engine, affecting the quantity of oil to other lubrication, etc. The friction loss does not increase during high-speed operation of the engine.

Furthermore since the oil bath 14 and the oil pan 1 communicates with each other, both the fuel supply system maintenance oil change and makeup, etc. of the lubrication oil supply system O _L, and the valve operating characteristic changing means for refueling system O _V It is not necessary to carry out independently at O _L and O _V. That is, by supplying the oil from the oil supply port 56 located immediately above the oil bath 14, the oil flows from the oil bath 14 to the oil pan 1 via the overflow pipe 53, and the oil is supplied to the oil bath 14 and the oil pan 1. Can be performed once, and maintenance work becomes easy. At this time, since surely certain amount of oil in the oil bath 14 is to be stored, the second oil pump P _C results in a malfunction inhale air is reliably prevented.

Further, the oil bath 14 contains not only oil leaked from each lubricating portion in the valve train such as the cam journal portion 12 and the cam shower portion 13. Since the oil is always supplied through the passage 15 when the engine is operating, the oil can be stably supplied to the oil bath 14 even if the oil amount due to the leakage is relatively small.

FIG. 6 shows another embodiment of the present invention, in which parts corresponding to the above-mentioned embodiment are denoted by the same reference numerals.

Oil supply port 56 provided in head cover 55
In some cases, the cover 58 is fixed to the head cover 55 so as to cover the lower portion of the oil supply port 56, and the cover 58 An introduction port 59 for introducing oil supplied from the port 56 into the head cover 55 is provided, and the introduction port 59 is disposed immediately above the oil bath 14.

In this way, similar to the above embodiment,
The oil supplied from the oil supply port 56 is guided to the introduction port 59 by the cover 58, and the oil can be reliably supplied to the oil bath 14 from the introduction port 59.

In each of the above embodiments, the intake valve has been described as an engine valve. However, the present invention can be implemented in connection with an exhaust valve as an engine valve.

[0038]

As described above, according to the first and second aspects of the present invention , the first oil pump for pumping hydraulic oil from the oil pan provided at the lower part of the engine body has an oil supply passage communicating with the hydraulic oil consuming portion. Are connected, a valve operating system lubricating branch oil passage communicating with each lubricating portion of the valve operating system including the valve operating cam shaft connected to the crankshaft is branched from the oil supply passage, and a cylinder head is provided with each of the valve operating systems. An oil bath capable of receiving the oil leaked from the lubricating portion and allowing the excess oil to overflow into the oil pan is provided, and a second oil pump for pumping hydraulic oil from the oil bath is provided with a valve operating characteristic changing means. Since it is connected to the hydraulic chamber, the capacity of the second oil pump can be set independently of the amount of oil required in the other lubricating parts, and increase in friction loss during high-speed rotation of the engine can be suppressed. And oil pan It is possible to simplify the maintenance work by in communication.

According to the first aspect of the present invention , since the branch oil passage for lubricating the valve train is connected to a passage directly communicating with the oil bath, the oil is always supplied from the oil pump to the oil bath when the engine is operating. As a result, the supply of oil to the oil bath can be stabilized.

According to the second aspect of the present invention , the oil supply port provided in the head cover connected to the cylinder head or the introduction port communicating with the oil supply port is disposed immediately above the oil bath. The oil can be reliably stored in the oil bath at the time of refueling, and the suction of air can be prevented to make the operation of the second oil pump smooth.

[Brief description of the drawings]

FIG. 1 is an oil supply system diagram of an engine body according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a configuration of a valve operating characteristic changing means.

FIG. 3 is a sectional view of the cylinder head taken along line 3-3 in FIG. 2;

FIG. 4 is an operation characteristic diagram of an engine valve.

FIG. 5 is a characteristic diagram of a required oil amount of a valve operating characteristic changing means with respect to an engine load.

FIG. 6 is a sectional view corresponding to FIG. 2 of another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Oil pan 5 Oil supply path 7 Branch oil path for valve system lubrication 8, 9 Hydraulic oil consumption section 11 Cylinder head 12, 13 Lubrication section 14 Oil bath 15 Passage 21 Valve operation characteristic changing means 27 Valve camshaft 41 Hydraulic chamber 55 head cover 56 intake valve P first oil pump P _C second oil pump as oil supply port 59 inlet E engine body V engine valve

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI F01M 11/02 F01M 11/02 F02D 13/02 F02D 13/02 G F02F 1/24 F02F 1/24 G (56) References Actual 60-1705 (JP, U) Full opening 61-177931 (JP, U) Full opening 63-138407 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F01M 1 / 06 F01L 13/00 301 F01M 1/02 F01M 11/02 F02D 13/02

Claims (2)

(57) [Claims] An operating characteristic of said engine valve (V) is changed between an engine valve (V) supported on a cylinder head (11) so as to be capable of opening and closing and a crankshaft according to a change in oil pressure in a hydraulic chamber (41). In an internal combustion engine provided with a valve operating device having variable valve operating characteristic changing means (21) interposed therein, a first oil pump for pumping hydraulic oil from an oil pan (1) provided at a lower portion of the engine body (E). An oil pump (P) is connected to an oil supply passage (5) leading to a hydraulic oil consuming unit (8, 9), and each lubrication unit (12, 12) of a valve train including a valve train camshaft (27) connected to a crankshaft. 13) A branching oil passage (7) for valve system lubrication leading to the oil supply passage (5) is branched from the oil supply passage (5) and
1) is provided with an oil bath (14) capable of receiving oil leaked from each lubricating portion (12, 13) of the valve train and capable of overflowing surplus oil into the oil pan (1). A second pumping operation oil from the oil bath (14).
The oil pump (P _C ) is provided with the valve operating characteristic changing means (2).
Is connected to 1) the hydraulic pressure chamber (41), said valve train lubrication min
The oil passage (7) has a direct connection to the oil bath (14).
A refueling device for an internal combustion engine, characterized in that a road (15) is connected . 2. The opening and closing operation of the cylinder head (11) is possible.
Between the engine valve (V) and the crankshaft
Actuation of the engine valve (V) in response to a change in oil pressure in the chamber (41)
A valve operating characteristic changing means (21) capable of changing characteristics is provided.
An internal combustion engine provided with a valve operating device comprising:
Hydraulic oil from the oil pan (1) provided at the lower part of (E)
The first oil pump (P) that pumps oil
The oil supply passage (5) leading to (8, 9) is connected
Each lubrication unit of the valve train including the valve train camshaft (27) connected to the shaft
The branch oil passage (7) for valve system lubrication leading to (12, 13)
The cylinder head (1) is branched from the oil supply passage (5).
1) leaks from each lubrication part (12, 13) of the valve train.
The oil pan,
(1) Oil bath (14) is provided to allow excess oil to overflow
A second pumping operation oil from the oil bath (14).
The oil pump (P _C ) is provided with the valve operating characteristic changing means (2).
The cylinder head (1 ) is connected to the hydraulic chamber (41) of the cylinder head (1).
An oil supply port (56) provided in a head cover (55) attached to 1) or an introduction port (59) leading to the oil supply port (56) is arranged directly above the oil bath (14). A refueling device for an internal combustion engine , characterized by :