JPH08170512A - Engine with valve opening/closing mechanism - Google Patents

Abstract

PURPOSE: To provide an engine with a valve opening/closing mechanism which can variously control in its simple construction, by reciprocating a first oil pressure piston in a first oil chamber by being synchronized with the rotation of an engine, and opening a valve member through a second oil pressure piston in a second oil chamber in a rocker arm communicated with the first oil chamber. CONSTITUTION: In a rocker shaft 10, an exhaust rocker arm 18 is swingably freely pivoted i.n a part opposite to an exhaust valve 16, and an oil chamber 33 in which an oil pressure piston 47 is fitted, is formed on the exhaust rocker arm 18. Meanwhile, an oil chamber 30 to which an oil pressure piston 31 is fitted, is formed in the protruding step part 112 of a cylinder block 11 opposed to an auxiliary cam 24 formed on a camshaft 23 together with intake/exhaust cams 21, 22, so that an oil passage 37 communicated with the oil chamber 33 is coupled with operating oil supply/exhaust passage means. When a solenoid valve 34 arranged in the operating oil supply/exhaust passage means, is driven to be closed according to output of operation condition detecting means, an oil pressure piston 47, that is, an exhaust valve 6 is opened/closed by being synchronized with the reciprocating motion of the oil pressure piston 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine with a valve opening / closing mechanism for returning a part of exhaust gas discharged from the engine to the combustion chamber again to intervene in the combustion, and in particular, the exhaust gas returned to the combustion chamber directly burns from an exhaust passage. The present invention relates to an engine with a valve opening / closing mechanism adapted to be supplied to a chamber.

[0002]

2. Description of the Related Art In an internal combustion engine, the combustion temperature of its combustion chamber increases or decreases depending on operating conditions, and in particular, as the combustion temperature rises, nitrogen oxides (hereinafter simply referred to as NO _X ) in exhaust gas are removed. The quantity tends to increase. Therefore, in order to prevent the increase of NO _X in the exhaust gas, it is effective to recirculate the exhaust gas to the combustion chamber again to suppress the increase of the combustion temperature and prevent the increase of NO _X in the exhaust gas. The device is in use. By the way, in the case where the recirculation (EGR) gas is first returned to the intake passage and then supplied to the combustion chamber, carbon contained in the exhaust gas must pass through the intake passage, the intake valve and the valve seat portion. Adhere to the inner walls of these passages to reduce the cross-sectional area of the passage,
There is a problem that the intake valve and the valve seat portion are worn early.

In order to solve this problem, for example, Shokai Sho 6
In Japanese Patent Application Laid-Open No. 0-145264, a third valve different from the intake and exhaust valves is provided in the combustion chamber so that it can be driven by an electromagnetic valve, and a third port for opening and closing the third valve is communicated with an exhaust passage. Then, an exhaust gas recirculation device is disclosed in which the drive means controls the third valve to open the intake valve at the opening timing of the intake valve via the electromagnetic valve. Further, in Japanese Patent Laid-Open No. 63-173840, a branch protrusion is provided on a part of the intake valve swing arm on the cylinder head.
A movable tappet that can drive the third valve to be opened and closed only when the stopper is engaged is provided on the branch protrusion, and when the EGR gas recirculates, the stopper is locked to the movable tappet so that the third tap is simultaneously performed with the intake valve.
An exhaust gas recirculation system is disclosed in which the valve is also driven to open and close, and the exhaust gas in the exhaust passage is directly recirculated to the combustion chamber via the third port.

According to both of these prior arts, the reduction of the cross-sectional area of the intake passage due to the recirculation of EGR gas is eliminated, and the deterioration of fuel consumption and the early wear of the intake valve and the valve seat portion due to carbon in the exhaust gas are eliminated.

[0005]

However, according to the technique disclosed in Japanese Utility Model Laid-Open No. 60-145264, the third valve is opened and closed by the solenoid valve, so that a relatively large solenoid valve drive current is required and the power source It is necessary to set a large capacity, which easily invites an increase in cost.
In the technique of Japanese Patent Publication No. 0, the movable tappet drives the third valve to open / close or is inactive by switching the stopper, which complicates the structure and lacks reliability.

Further, in both of the prior arts, the third valve is disposed in the combustion chamber opposite to the intake / exhaust valve, and the third valve needs to be separately provided in the portion facing the combustion chamber on the cylinder head side. Therefore, when the installation space for the intake / exhaust valve is set, the installation space for the third valve is taken into consideration, so that the installation space is likely to be restricted and may be narrowed in some cases, resulting in a problem that the engine output is restricted. It is easy to occur. It is an object of each of the first to sixth aspects of the present invention to provide a reliable engine with a valve opening / closing mechanism that suppresses an increase in cost and complexity of the structure.

Particularly, in the inventions of claims 2 and 4 to 6, when the exhaust gas recirculation device for directly supplying the exhaust gas as EGR gas to the combustion chamber is provided, the installation space of the intake and exhaust valves is restricted. It is also an object to provide an engine with a valve opening / closing mechanism.

[0008]

In order to achieve the above object, a first aspect of the present invention is directed to a valve member for opening and closing an opening of a passage communicating with a combustion chamber of an engine, which is swingable on a cylinder head of the engine. A rocker arm that is supported and has one end reciprocated by rotation of the engine and the other end operatively connected to a stem portion of the valve member to drive the valve member, the cylinder head or cylinder block of the engine. A first oil chamber formed therein, a working oil supply / discharge passage means for communicating at least the first oil chamber and a low-pressure oil supply source to supply low-pressure oil to the first oil chamber, and one end of the first oil chamber A first slidably fitted in the chamber and reciprocally moved in the first oil chamber in synchronization with rotation of the engine;
Hydraulic piston, the first formed in the rocker arm
A second oil chamber communicated with the oil chamber, one end of which is slidably fitted into the second oil chamber and the other end of which is formed by high pressure oil generated by the first hydraulic piston to cause the valve member to move the valve member. Second hydraulic piston that can be driven in the opening direction, a solenoid valve that is provided in the hydraulic oil intake / exhaust passage means and that opens and closes the hydraulic oil supply / exhaust passage means, an operating state detecting means that detects the operating state of the engine, and the operating state When the solenoid valve is driven to close according to the output of the detection means to shut off the hydraulic oil supply / discharge passage means, the high pressure oil generated in synchronization with the reciprocating movement of the first hydraulic piston is used as the second oil chamber. To reciprocate the second hydraulic piston.

According to a second aspect of the present invention, in the engine with the valve opening / closing mechanism according to the first aspect, the valve member is an exhaust valve that opens and closes an exhaust passage, and the control means controls the intake stroke of the engine. In order to drive the exhaust valve in the opening direction to recirculate the exhaust gas, the solenoid valve is controlled to be driven in the closing direction for a predetermined period.

According to a third aspect of the present invention, in the engine with the valve opening / closing mechanism according to the first aspect, the second oil chamber is provided so as to abut on the top of the other end of the rocker arm. To do.

The invention of claim 4 is the invention of claims 1 to 3.
In the engine with a valve opening / closing mechanism described above, the hydraulic oil supply / discharge passage means includes a first oil passage that connects the first oil chamber and the second oil chamber via a support shaft of the rocker arm, and a first oil passage. The electromagnetic valve is provided in the second oil passage, and has a second oil passage that connects one of the oil passage or the first oil passage and the main gallery of the engine as the low-pressure oil supply source. It is characterized by

According to a fifth aspect of the present invention, in the engine with the valve opening / closing mechanism according to the fourth aspect, the hydraulic oil supply / discharge passage means comprises:
In the second oil passage between the electromagnetic valve and the main gallery, a relief valve capable of discharging the high pressure oil exceeding the oil pressure of the low pressure oil is provided.

According to a sixth aspect of the present invention, in the engine with a valve opening / closing mechanism according to the fourth aspect, the hydraulic oil supply / discharge passage means is provided in the second oil passage from the main gallery side to the first oil passage.
A one-way valve that allows only the flow of hydraulic oil in the oil passage side is provided, and the first oil passage is discharged to discharge the high-pressure oil generated in synchronization with the reciprocating movement of the first hydraulic piston, or The third that connects one of the first oil chambers and the working oil sump
An oil passage, and the solenoid valve is provided in the third oil passage.

[0014]

According to the present invention, the rocker arm reciprocates and the valve member drives the opening and closing of the opening of the combustion chamber in conjunction with the engine drive.
At this time, the first hydraulic piston is caused to reciprocate in the first oil chamber formed in the cylinder head or the cylinder block in synchronization with the rotation of the engine, and the second hydraulic piston in the rocker arm communicated with the first oil chamber. Since the second hydraulic piston in the oil chamber is formed so that the valve member can be driven to open, and further, the solenoid valve is provided on the working oil supply / discharge passage means that connects the first oil chamber and the low-pressure oil supply source, the electromagnetic valve is provided. When the valve shuts off the hydraulic oil supply / discharge passage means and shuts off the first oil chamber and the second oil chamber from the low-pressure oil supply source, the high-pressure oil generated by the drive of the first hydraulic piston in the first oil chamber Join the second hydraulic piston in the two oil chambers,
This second hydraulic piston can drive the valve member in the opening direction.

According to a second aspect of the present invention, the valve member of the engine with the valve opening / closing mechanism according to the first aspect is an exhaust valve for opening and closing the exhaust passage, and the control means controls the electromagnetic valve in the intake stroke of the engine. When the exhaust valve is driven in the closing direction for a predetermined period of time, the exhaust valve is driven in the opening direction, so that the exhaust valve is opened and the exhaust gas recirculates even if the exhaust valve is not in the exhaust stroke.

According to a third aspect of the present invention, the second oil chamber of the engine with the valve opening / closing mechanism according to the first aspect is provided at the other end of the rocker arm, and the second hydraulic piston is provided at the stem portion of the valve member. Since it abuts on the top, when the solenoid valve shuts off the low-pressure oil supply source, the high-pressure oil generated by driving the first hydraulic piston in the first oil chamber is the second oil chamber in the second oil chamber at the other end of the rocker arm. In addition to the hydraulic piston, this second hydraulic piston can drive the valve member in the opening direction.

The invention of claim 4 relates to claims 1 to 3.
In the engine with a valve opening / closing mechanism described above, in particular, the hydraulic oil supply / discharge passage means includes a first oil passage that connects the first oil chamber and the second oil chamber via a support shaft of the rocker arm, and a first oil passage. A second passage that connects one of the first oil passage or the first oil passage and the main gallery of the engine as the low-pressure oil supply source.
And a solenoid valve provided in the second oil passage,
When the solenoid valve drives the second oil passage in the closing direction for a predetermined period of time, the exhaust valve drives in the opening direction, so that the exhaust valve is opened to perform exhaust gas recirculation even in the exhaust stroke.

According to a fifth aspect of the present invention, the hydraulic fluid supply / discharge passage means for an engine with a valve opening / closing mechanism according to the fourth aspect is particularly provided in the second oil passage between the solenoid valve and the main gallery, where the low pressure is applied. Since the relief valve capable of discharging the high pressure oil exceeding the oil pressure of the oil is provided, it is possible to restrict the supply of the excessively high oil pressure to the first oil passage.

According to a sixth aspect of the present invention, the hydraulic oil supply / discharge passage means for an engine with a valve opening / closing mechanism according to the fourth aspect is particularly arranged in the second oil passage extending from the main gallery side to the first oil passage side. A one-way valve that allows only the flow of hydraulic oil is interposed, and the first oil passage or the first oil for discharging the high-pressure oil generated in synchronization with the reciprocating movement of the first hydraulic piston. When the solenoid valve provided in the third oil passage is driven in the closing direction for a predetermined period of time, the exhaust valve is driven in the opening direction.
Even if the exhaust valve is not in the exhaust stroke, the valve is opened to recirculate the exhaust gas.

[0020]

1 to 3, there is shown an engine E having a valve opening / closing mechanism as an embodiment of the present invention. The engine E is an in-line 4-cylinder (first cylinder # 1 to fourth cylinder # 4) OHV type engine, and includes a cylinder block 11, a cylinder head 12, a cylinder head cover (not shown), a cylinder block lower, an oil pan, and the like. Inside each of them, combustion chambers C in which pistons (not shown) are slidably fitted are arranged in rows. The first cylinder # 1 will be mainly described here because each cylinder has the same configuration. Here, intake / exhaust valves 15 and 16 for opening / closing between the combustion chamber C and the intake / exhaust ports 13 and 14 are attached to each cylinder facing portion of the cylinder head 12, and an ignition plug (not shown) is provided.

The intake port 13 is connected to an air cleaner (not shown) via an intake branch pipe (not shown) and an intake pipe (not shown) to form an intake passage. On the other hand, the exhaust port 14
Is connected to the muffler side (not shown) through an exhaust manifold or an exhaust pipe (not shown). Here, the cylinder head 12
A rocker shaft 10 is provided in an upper part of the cylinder in the direction of arrangement of the first cylinder (# 1) to the fourth cylinder (# 4), and the shaft is supported by a plurality of bearing portions 40. Supply / exhaust rocker arms 17 and 18 are pivotally attached to the rocker shaft 10 at the portions facing the intake and exhaust valves 15 and 16 so as to be swingable. The intake / exhaust valve 1 is provided at one end of each of the supply / exhaust rocker arms 17 and 18.
5, 16 and the other end is connected to the push rod 19, respectively. The lower end of the second hydraulic piston 47 abuts on the end of the exhaust rocker arm 18 facing the upper end of the stem of the exhaust valve 16, and the upper end of the second hydraulic piston 47 is fitted into the second oil chamber 33 of the exhaust rocker arm 18. . Here, the second oil chamber 3
When the pressure is low, the second hydraulic piston 47 moves to the retracted position (Fig. 2).
The position shown in the solid line in FIG.
Is high, the second hydraulic piston 47 is held at the protruding position (see FIG. 2) H2.

As shown in FIG. 2, the lower end of the push rod 19 whose upper end is engaged with the other end of the discharging rocker arm 18 contacts the discharging cam 22 via the cup-shaped slider 20. Here, as shown in FIG. 2, a side space 28 for housing the push rod 19 is formed between the outer wall 114 and the inner wall 111 on one side of the cylinder block 11. As shown in FIG. 4, a projecting step portion 112 is continuously formed in a lower portion of the inner wall 111, and both guide holes 113 corresponding to the supply / discharge valves 15 and 16 are arranged in parallel there, and each slider 20 is provided therein. Is slidably inserted. Although the discharge rocker arm 18 and the discharge cam 22 are shown in FIG.
Supply rocker arm 17, push rod 19, slider 2
0 and the intake cam 21 are also formed (see FIG. 4). In addition,
In FIG. 1, only the cutout portion of the projecting step 112 is shown in a plan view.

Here, the intake cam 21 and the exhaust cam 22 are formed integrally with the cam shaft 23 together with an auxiliary cam 24 which will be described later, and these three cams form a set, and face each cylinder on the cam shaft 23. It is sequentially formed at the positions. The camshaft 23 is pivotally supported at a plurality of locations on a bearing portion 25 projecting from the inner wall 111 of the cylinder block 11. A timing gear 26 is attached to one end of the camshaft 23. As a result, the camshaft 23 can be driven to rotate at a speed half the engine speed. As shown in FIG.
The intake cam 21 and the exhaust cam 22 are formed so that the crank angle is 180 ° and the cam angle is 90 ° out of phase, and the auxiliary cam 24 is substantially in phase with the intake cam 21 (here, the cam angle is set to be delayed by θo). It is formed so that the lift circle of the auxiliary cam 24 is located in the latter part of the intake stroke. The projecting step 1 of the inner wall 111 facing the auxiliary cam 24
A first oil chamber 30 fitted with a first hydraulic piston 31
Is formed. A spring 48 that pushes back the first hydraulic piston 31 to the cam side is provided in the first oil chamber 30, and a first oil passage 37 communicating with the second oil chamber 33 at one end of the discharge rocker arm 18 and a hydraulic oil supply are provided at the upper end. The discharge passage means S is connected.

Although the first oil chamber 30 in which the first hydraulic piston 31 is fitted to the projecting step 112 is formed in FIG. 4, in some cases, as shown in FIG. 13, the inner wall of the cylinder block is You may form the 1st oil chamber 30 'which fitted the 1st hydraulic piston 31' at the part which faces the intake cam 21 of 111. In this case, the intake cam 21 is configured to drive the intake valve 15 side via the slider 20 and the push rod 19 as in FIG. 4, and here, in particular, the cam angle advances 90 ° with respect to the slider 20. A first oil chamber 30 'in which a first hydraulic piston 31' is fitted is provided at the position. In this case, the auxiliary cam 24 can be eliminated here by making the intake cam 21 also function as the auxiliary cam 24 in FIG. The first oil chamber 30 ′ here is the first oil passage 3
7 and the second oil chamber 33 at one end of the rocker arm 18 and the hydraulic oil supply / discharge passage means S.

The hydraulic oil supply / discharge passage means S shown in FIGS. 1 and 4 communicates with one of the first oil passages 37 and the main gallery 36 of the engine as a low-pressure oil supply source. A throttle 323 at the end of the passage 32 on the side of the main gallery 36, and a relief valve 39 connecting the second oil passage 32 and the drain passage 37 are provided. Moreover, the second oil passage 32 is connected to the main portion 320, the low-pressure oil branch passage 321 communicating with the first oil chamber 30 of each cylinder via the one-way valve 322, and the first oil chamber 30 side of the low-pressure oil branch passage 321. It is composed of a third oil passage 324 that branches and communicates with the drain passage 37 and the hydraulic oil sump 35 via the solenoid valve 34. The throttle 323 of the second oil passage 32 is formed to reduce the pressure of the high-pressure oil in the main gallery 36, and the relief valve 39 operates when the oil pressure of the low-pressure oil in the second oil passage 32 after passing through the throttle 323 exceeds a predetermined value. It is configured to actuate pressure regulation to drain hydraulic pressure.

As shown in FIGS. 1 and 7, the solenoid valve 34 has an oil passage on the side of the first oil chamber 30 with respect to the one-way valve 322 as a drain passage 3.
7 is a normally open valve which is configured to be able to communicate with 7, and whose opening and closing is controlled by the output of an engine control unit 42, which will be described later, and which is opened when turned off and closed when turned on. The solenoid valve 34 of the first cylinder (# 1) is connected to an engine control unit (hereinafter simply referred to as ECU) 42 via a drive circuit 41.
Similarly, the solenoid valves 34 of the other cylinders are also connected to the ECU 42 via the drive circuit 41. As described above, the first cylinder facing portion of the engine with the valve opening / closing mechanism has been mainly described, but the same configuration is also provided for the other cylinder facing portions, and a duplicate description thereof will be omitted here.

Here, as shown in FIG. 1, the ECU 42 detects the crank angle dθ and the engine rotation speed Ne, the throttle opening θs which is the load information, the water temperature Wt, and the intake pipe pressure Pi in the operating state. The crank angle sensor 43, the load sensor 44, the water temperature sensor 45, and the intake pressure sensor 46, which are means, are used for detection. ECU 42
Is a normal engine control, which performs well-known control processing such as fuel injection amount control of the engine E and ignition timing control according to the output of the operating state detection means, and performs control according to the EGR control program of FIG. 8 at appropriate times. Do. Especially the EC here
U42 is a solenoid valve 34 according to the output of the operating state detecting means.
Is closed to shut off the hydraulic oil supply / discharge passage means S, the high-pressure oil generated in synchronization with the reciprocating movement of the first hydraulic piston 31 is supplied to the second oil chamber 33 to drive the second hydraulic piston 47. Reciprocate.

Further, in the intake stroke of the engine, the exhaust valve 16
Is provided in the opening direction to recirculate the exhaust gas, the electromagnetic valve 34 is driven in the closing direction for a predetermined period. In the ECU 42, the crank angle sensor 43 detects the crank angle dθ and the engine speed Ne, the throttle opening sensor 44 indicates the throttle opening θs, the water temperature sensor 45 indicates the engine cooling water temperature Tw, and the intake pressure sensor 4
The intake pipe pressure Pi is taken from 6 respectively.

The operation of the engine with the valve opening / closing mechanism will be described below.
The EGR control program of FIG. 8 and the solenoid valve drive program of FIG. 9 will be described. When the engine E of FIG. 1 is driven, the intake / exhaust valves 15 and 16 of each cylinder are driven in a predetermined cylinder order by the operation of the valve system. Since similar control is performed in parallel for each cylinder while maintaining a predetermined crank angle deviation, the operation will be described mainly for the first cylinder.

As shown in FIG. 5, in the exhaust stroke, the exhaust valve 16
Lift amount EV increases and decreases, and the lift amount IV of the intake valve 15 increases and decreases in the intake stroke after the exhaust top dead center TDC1, the mixture flows from the intake port 13 into the combustion chamber C in the intake stroke, and the EGR region A1 In the latter part of the intake stroke, the exhaust valve 16 is lifted by the second hydraulic piston 47 (see FIG. 6A).
The valve is opened at v, and a part of the exhaust gas flows into the combustion chamber 1C as EGR gas. After the subsequent compression, compression top dead center TD
The compressed air-fuel mixture is ignited at an ignition timing near C2, and the air-fuel mixture is combusted in the combustion process to generate an output.

When the engine E is driven, the pump 3
1 supplies high-pressure oil to the main gallery 36, a part of which is decompressed by the throttle 323, and the second oil passage 32, the low-pressure oil branch passage 321 having the one-way valve 322, the first oil passage 37, and the solenoid valve 34 are connected. It flows down sequentially to the provided third oil passage 324 and drain passage 37. In addition, the relief valve 39 operates to adjust the pressure of the low pressure oil in the second oil passage 32 so as to maintain a predetermined value.
When the engine key (not shown) is turned on, the ECU 42 of this engine executes a normal main routine based on various operation information, and executes fuel control and ignition drive control at appropriate times.
In particular, the process proceeds to the EGR control routine of FIG. 8 and the solenoid valve drive routine of FIG.

In the EGR control routine, first, various operating information of the engine is read, and then the process proceeds to step a2. Here, an operating range setting map m1 as shown in FIG. 6A is created in advance, and the EGR range A _L or the non-EGR range A _H is set according to the current engine speed Ne and the throttle opening θs.
Or set. Note that the EGR range A _L here is the medium load θ.
Although the determination is made based on the threshold value of s1, the threshold value of low load θs2 is added as shown by a chain double-dashed line in some cases, and low load θs
The EGR amount may be increased or decreased with the threshold value of 2 as the boundary. EG
In the R area A _L , the drive signal is set to ON in step a4, and in the non-EGR area A _H , the drive signal is set to OFF in step a5, and each returns to the main routine (not shown).

When the predetermined crank angle θe in the intake stroke of each cylinder is reached, the electromagnetic valve drive routine is started. At step b1 here, whether the current drive signal D is on or off is read, at step b2 the solenoid valve 34 is driven by the current drive signal Dn, and at step b3, a predetermined drive time Te is waited for, Thereafter, in step b4, the solenoid valve 34 is turned off, and the process returns to the main routine. Therefore, the EGR area A
_When each solenoid valve 34 is turned on at _L and the third oil passage 324 is closed, the oil passage on the first oil chamber 30 side of the one-way valve 322 is closed with respect to the second oil passage 32 and the drain passage 37. Then, each first hydraulic piston 3 driven by the auxiliary cam 24
The high-pressure oil generated in synchronization with the reciprocating motion of
The exhaust valve 16 is reciprocated through the second hydraulic piston 47 in the lift pattern ev shown in FIG. 5, and the exhaust valve 16 is opened during the intake stroke to supply the exhaust gas to the combustion chamber C as EGR gas. As a result, in the combustion chamber C, the mixture gas EG
The R gas is mixed, and an excessive rise in the combustion temperature in the combustion chamber can be regulated, and the generation of NO _X can be reduced.

On the other hand, when each solenoid valve 34 is kept off in the non-EGR region A _H , the third oil passage 324 is kept open, and the one oil valve 30 and the solenoid valve 34 make the first oil chamber 30 open. The oil passage on the side communicates with the second oil passage 32 and the drain passage 37, and each first hydraulic piston 3 driven by the auxiliary cam 24 does not supply high-pressure oil to the second oil chamber 33. The second hydraulic piston 47 continues to hold the retracted position H1, and the exhaust valve 16 does not open during the intake stroke. As a result, only the air-fuel mixture is supplied to the combustion chamber C in the non-EGR region A _H , and a predetermined output can be secured. As described above, the engine with a valve opening / closing mechanism of FIG. 1 is provided with the solenoid valve 34 that is a normally open on-off valve, and the first oil passage 37 side is sealed by the solenoid valve 34 during the intake stroke,
The auxiliary cam 24 switches the second hydraulic piston 47 from the retracted position H1 to the protruding position H2 and supplies the exhaust gas to the combustion chamber C as EGR gas. Here, a second embodiment, which is a modification of the first embodiment, will be described. The second embodiment is similar to the first embodiment in FIG. 1 except that a duty valve (not shown) is used in place of the solenoid valve 34 of the first embodiment, and the drive control of the duty valve is different. Because,
Here, only the EGR control routine and the duty valve drive routine will be described, and the other redundant description will be omitted.

In the EGR control routine in the second embodiment, as shown in FIG. 11, various operating information of the engine is read, and in step s2 an operating range setting map m2 as shown in FIG. 6 (b) is created in advance. Incidentally, the high EGR range A _L is set according to the current engine speed Ne and the throttle opening θs.
1. Set low EGR range A _L 2 or non-EGR range A _H. It should be noted that the high EGR region A _L 1 here is determined as a region of low load θs2 or less, the low EGR region A _L 1 is determined as a region of medium load θs1 or less and low load θs2 or more, and non-EGR region A _H
Is determined as a region in which the medium load θs1 is exceeded. High EGR
In the area A _L1 , a relatively large duty ratio Du1 is set in step s4, whereby the flow passage throttle amount is increased to secure the lift pattern ev at the high protruding position H2 _H shown in FIG. In the EGR region A _L 2, the duty ratio Du is relatively small in step s5.
2 (<Du1) is set, thereby reducing the flow passage restriction amount to secure the lift pattern ev at the low protruding position H2 _L shown in FIG. 10, and the process returns to the main routine side (not shown). On the other hand, the process proceeds to the non-EGR region A in _H step s6, so as not to exhaust valve 16 is actuated during the intake stroke, to set the duty ratio Du2 zero (fully open), the flow returns to the main routine.

When the predetermined crank angle θe in the intake stroke of each cylinder is reached, the routine proceeds to the duty valve drive routine of FIG. At step c1, the current duty ratio Dun (Du1 to Du3) is read, and step c
In step 2, the duty valve (not shown) is driven with the current duty ratio Dun, and in step c3, the predetermined drive time T
After the elapse of e, the duty ratio is returned to zero in step c4, and the process returns to the main routine. As described above, in the second embodiment, in the high EGR region A _L 1, the flow passage throttle amount is increased to secure the lift pattern ev at the high protruding position H2 _H , and the exhaust gas in the combustion chamber C is relatively large as EGR gas. By supplying the gas, it is possible to reliably regulate an excessive increase in the combustion temperature, and as a result, it is possible to reliably reduce NO _{X in} the exhaust gas. On the other hand, in the low EGR region A _L2 , the flow passage throttle amount is reduced to secure the lift pattern ev at the low protruding position H2 _L , and the exhaust gas is supplied to the combustion chamber C as EGR gas in a relatively small amount to prevent excessive combustion temperature. The output of the exhaust valve 16 can be controlled in the non-EGR region A _H while the output of the exhaust valve 16 can be controlled while the rise of
The output can be reliably ensured without operating during the intake stroke.

[0037]

As described above, according to the present invention, the first hydraulic piston reciprocates in the first oil chamber formed in the cylinder head or the cylinder block in synchronization with the rotation of the engine. A second hydraulic piston in a second oil chamber in the rocker arm, which communicates with the first oil chamber, enables the valve member to open and drive, and further, a hydraulic oil supply / discharge passage means for communicating the first oil chamber with a low-pressure oil supply source. High pressure generated by driving the first hydraulic piston in the first oil chamber when the upper solenoid valve shuts off the hydraulic oil supply / discharge passage means and shuts off the first oil chamber and the second oil chamber side from the low-pressure oil supply source. The oil is added to the second hydraulic piston in the second oil chamber, and this second hydraulic piston can drive the valve member in the opening direction. Therefore, when the rocker arm swings, the valve member is opened and the rocker arm swings. The valve member can be opened when it is not moving Can drive the valve member with two control systems,
It is possible to achieve engine control capable of diverse control while suppressing cost increase and structural complexity.

According to a second aspect of the present invention, in particular, the valve member of the first aspect is the exhaust valve, and when the solenoid valve is driven in the closing direction for a predetermined period in the intake stroke, the exhaust valve is driven in the opening direction. It becomes possible to open the exhaust gas recirculation even during the intake stroke, and to provide the exhaust gas recirculation device, it is possible to provide the engine with the valve opening / closing mechanism in which the installation space of the intake / exhaust valve is not restricted.

The invention of claim 3 is particularly the second aspect of claim 1.
The oil chamber is provided at the other end of the rocker arm, and the second hydraulic piston abuts the top of the stem portion of the valve member. Therefore, when the solenoid valve shuts off the low pressure oil supply source, the first hydraulic piston in the first oil chamber The high-pressure oil generated by the driving of the second hydraulic piston is added to the second hydraulic piston, and this second hydraulic piston can drive the valve member in the opening direction, so that diverse engine control can be performed without increasing the cost and complicating the structure. Can be achieved.

According to a fourth aspect of the present invention, in particular, the hydraulic oil supply / discharge passage means according to the first to third aspects connects the first oil chamber and the second oil chamber to each other via the support shaft of the rocker arm. And a second oil passage that connects the first oil passage or one of the first oil passage and the main gallery. When the solenoid valve drives the second oil passage in the closing direction for a predetermined period, the exhaust valve Driven in the opening direction, the exhaust valve can be opened even during the intake stroke to perform exhaust gas recirculation, and when installing the exhaust gas recirculation device, the valve opening / closing mechanism does not restrict the installation space of the intake / exhaust valve. An engine can be provided.

According to a fifth aspect of the invention, in particular, the hydraulic oil supply / discharge passage means of the fourth aspect has a relief valve capable of discharging high-pressure oil exceeding the hydraulic pressure of the low-pressure oil in the second oil passage, and the first oil passage. Since it is possible to restrict the supply of an excessively high hydraulic pressure, it is possible to more reliably drive the exhaust valve in the opening direction when the electromagnetic valve drives the second oil passage in the closing direction for a predetermined period.

According to the sixth aspect of the present invention, in particular, the hydraulic oil supply / discharge passage means according to the fourth aspect is arranged in the second oil passage from the main gallery side to the first oil passage.
A one-way valve that allows only the flow of hydraulic oil in the oil passage side is installed, and one of the first oil passage or the first oil chamber and the hydraulic oil sump to discharge the high-pressure oil generated by the first hydraulic piston. When the solenoid valve provided in the third oil passage is driven in the closing direction for a predetermined period, the exhaust valve is driven in the opening direction, so that the exhaust valve opens even during the intake stroke. Thus, the exhaust gas recirculation can be performed, and in providing the exhaust gas recirculation device, it is possible to provide the engine with the valve opening / closing mechanism in which the installation space of the intake / exhaust valve is not restricted.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an engine with a valve opening / closing mechanism as an embodiment of the present invention.

FIG. 2 is a cutaway vertical sectional view of a main part of the engine of FIG.

3 is a partially cutaway plan sectional view of the engine of FIG. 1. FIG.

FIG. 4 is a sectional view taken along line XX in FIG.

5 is a lift pattern diagram of intake and exhaust valves of the engine of FIG. 1. FIG.

6A is a characteristic diagram of an operating range setting map used by the engine of FIG. 1, and FIG. 6B is a characteristic diagram of an operating range setting map used by an engine with a valve opening / closing mechanism as a second embodiment.

7 is an enlarged cross-sectional view of a solenoid valve used in the engine of FIG.

8 is a flowchart of an EGR control routine used by the engine of FIG.

9 is a flowchart of a solenoid valve drive routine used by the engine of FIG.

FIG. 10 is a lift pattern diagram of intake and exhaust valves of an engine with a valve opening / closing mechanism according to a second embodiment.

FIG. 11 is a flowchart of an EGR control routine used by the engine of the second embodiment.

FIG. 12 is a flowchart of a solenoid valve drive routine used by the engine of the second embodiment.

13 is a cross-sectional view of essential parts of a first hydraulic chamber and a first hydraulic piston used in place of the first hydraulic chamber and the first hydraulic piston of the engine with a valve opening / closing mechanism of FIG. 1.

[Explanation of symbols]

 E engine 10 rocker shaft 11 cylinder head 12 cylinder block 15 intake valve 16 exhaust valve 18 exhaust rocker arm 21 exhaust cam 22 intake cam 23 camshaft 24 auxiliary cam 30 first hydraulic chamber 31 first hydraulic piston 32 second oil passage 320 main part 321 Low pressure oil branch passage 322 One-way valve 324 Third oil passage 33 Second hydraulic chamber 34 Electromagnetic valve 36 Main gallery 37 First oil passage 42 ECU 43 Crank angle sensor 44 Load sensor 47 Second hydraulic piston 49 Pump C Combustion chamber S S operation Oil supply / drain passage means

Claims (6)

[Claims] 1. A valve member which opens and closes an opening of a passage communicating with a combustion chamber of an engine, is swingably supported on a cylinder head of the engine, and has one end reciprocally moved by rotation of the engine and the other end. Is a rocker arm operatively connected to a stem portion of the valve member to drive the valve member, a first oil chamber formed in the cylinder head or cylinder block of the engine, and low pressure oil in the first oil chamber. To supply at least the first oil chamber and the low-pressure oil supply source, one end of which is provided by slidingly inserting one end into the first oil chamber so as to be synchronized with the rotation of the engine. A first hydraulic piston reciprocating in the first oil chamber, a second oil chamber formed in the rocker arm and communicating with the first oil chamber, and one end slidably fitted in the second oil chamber. Provided by inserting And a second hydraulic piston, the other end of which is capable of driving the valve member in the opening direction of the valve member by the high pressure oil generated by the first hydraulic piston, and the hydraulic oil supply / discharge passage provided in the hydraulic oil suction / discharge passage means. Electromagnetic valve for opening and closing the means, operating state detecting means for detecting the operating state of the engine, when the electromagnetic valve is driven to close according to the output of the operating state detecting means to shut off the hydraulic oil supply / discharge passage means, An engine with a valve opening / closing mechanism, characterized in that high-pressure oil generated in synchronization with the reciprocating movement of the first hydraulic piston is supplied to the second oil chamber to reciprocate the second hydraulic piston. 2. The valve member is an exhaust valve that opens and closes an exhaust passage, and the control means controls the intake stroke of the engine.
2. The engine with a valve opening / closing mechanism according to claim 1, wherein the solenoid valve is controlled to be driven in a closing direction for a predetermined period so as to drive the exhaust valve in an opening direction to recirculate exhaust gas. 3. The engine with a valve opening / closing mechanism according to claim 1, wherein the second oil chamber is provided so as to come into contact with the top of the other end of the rocker arm. 4. The hydraulic oil supply / discharge passage means includes a first oil passage that connects the first oil chamber and the second oil chamber via a support shaft of the rocker arm, the first oil passage, or the first oil passage. The electromagnetic valve has one of the first oil passages and a second oil passage communicating with the main gallery of the engine as the low-pressure oil supply source.
The engine with a valve opening / closing mechanism according to claim 1, wherein the engine is provided in the second oil passage. 5. The hydraulic oil supply / discharge passage means has a relief valve in the second oil passage between the solenoid valve and the main gallery, which is capable of discharging the high pressure oil exceeding the hydraulic pressure of the low pressure oil. The engine with a valve opening / closing mechanism according to claim 4, wherein 6. The hydraulic oil supply / discharge passage means is provided with a one-way valve which allows only the flow of hydraulic oil in the second oil passage from the main gallery side toward the first oil passage side, and A first oil passage for discharging the high-pressure oil generated in synchronization with the reciprocating movement of the first hydraulic piston, or a third oil passage communicating one of the first oil chamber and the working oil sump. The engine with a valve opening / closing mechanism according to claim 4, wherein the solenoid valve is provided in the third oil passage.