JPH10184328A - Engine brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify piping for supplying hydraulic oil to a hydraulic driving means and make increase of engine brake force variable. SOLUTION: This engine brake device has a release piston 5 for timely release compression pressure by lifting exhaust valves 1, 2 of respective cylinders and a hydraulic pressure driving means 7 for driving the release piston 5 by generating high oil pressure in a hydraulic circuit 6 and a hydraulic pressure control means 8 for controlling such that designated high hydraulic pressure can be formed by timely introducing hydraulic oil to the hydraulic circuit 6. An operation switching means 14 for switching from operation to non-operation by feeding and discharging operating oil to the hydraulic pressure control means 8 is disposed in a housing block 13 of the hydraulic circuit 6 disposed at every cylinder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine brake device for increasing an engine braking force by releasing a compression pressure in a cylinder.

[0002]

2. Description of the Related Art Recently, there has been proposed an engine brake device which increases an engine braking force by lifting an exhaust valve other than an exhaust stroke and releasing a compression pressure in a cylinder when an engine brake is used. I have.
As a drive mechanism for lifting the exhaust valve, a housing having a hydraulic circuit is provided above the cylinder head,
2. Description of the Related Art There has been known an apparatus that generates a high oil pressure in a circuit to push a piston (release piston) for an exhaust valve lift.

[0003]

The drive mechanism of this type of engine brake device performs an ON / OFF operation by supplying and discharging hydraulic oil to and from its hydraulic circuit. The oil piping must be complicated in shape to avoid interference with other parts. For this reason, there has been a problem that the component manufacturing cost is increased and the assemblability is poor. It is desirable that the increase in the engine braking force be made variable in accordance with driving conditions such as the load weight and the vehicle speed. However, such a variable engine braking device has not been available.

[0004]

A release piston for lifting the exhaust valve of each cylinder to release the compression pressure appropriately,
Hydraulic drive means for generating a high oil pressure in the hydraulic circuit to drive the release piston, and hydraulic control means for appropriately guiding the operating oil pressure to the hydraulic circuit and controlling the hydraulic oil in a state where a predetermined high oil pressure can be formed, In a housing of a hydraulic circuit provided for each cylinder, operation switching means for switching between operation and non-operation by supplying and discharging operating oil pressure to and from the hydraulic control means is provided. The operation switching means includes a switching spool valve for communicating or shutting off a hydraulic oil passage connecting the hydraulic oil supply source and the hydraulic control means, and an electromagnetic actuator for operating the switching spool valve according to an operation condition. Is preferred. The hydraulic oil supply source may have a valve operating lubricating oil passage for supplying lubricating oil to the valve operating mechanism.

[0005] With the above configuration, when the operation switching means supplies a predetermined operating oil pressure to the hydraulic control means during the operation of the engine brake, the hydraulic control means fills the hydraulic circuit with the operating oil so that a high oil pressure can be formed. I do. The hydraulic drive means generates a high oil pressure in the hydraulic circuit by a dedicated cam or the like and operates the release piston. The release piston lifts the exhaust valve to release the compression pressure in the cylinder and appropriately increases the engine braking force.

[0006]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 and 2 show an example in which an engine brake device according to the present invention is applied to a four-valve engine in which each cylinder C is provided with a pair of exhaust valves 1 and 2 and intake valves 3 and 4. Things. This engine brake device
A release piston 5 for lifting the exhaust valves 1 and 2 of each cylinder C to release the compression pressure appropriately, and a hydraulic drive means 7 for driving the release piston 5 by the high hydraulic pressure generated in the hydraulic circuit 6 And hydraulic control means 8 for appropriately guiding the operating oil pressure to the hydraulic circuit 6 and controlling the hydraulic oil to a state in which a predetermined high oil pressure can be formed. The release piston 5 is provided in the vicinity of a pair of exhaust valves 1 and 2 connected by a valve bridge 9 and includes a release piston housing 10.
The cylinder chamber 11 is vertically movably held.
A transmission member 12 for transmitting the operation of the release piston 5 to the exhaust valves 1 and 2 is provided below the cylinder chamber 11. In the housing block 13 of the hydraulic circuit 6 provided for each cylinder C, operation switching means 14 for switching between operation and non-operation by supplying and discharging operating hydraulic pressure to and from the hydraulic control means 8 is provided. .

The exhaust valves 1 and 2 extend upward from the valve bodies 1a and 2a seated at the open ends (valve seats 16) of the exhaust ports 15 facing the engine cylinder C, and from the axial centers of the valve bodies 1a and 2a. And the valve shafts 1b and 2b. Valve shaft 1
Each of b and 2b is provided with a return spring 18 held by a retainer 17, and urges the exhaust valves 1 and 2 in the valve closing direction (upward). The valve bridge 9 has a substantially T-shape in a side view, and the top end of the valve shaft 1b of one of the exhaust valves 1 is engaged and held at one end of a horizontal portion thereof. An adjustable screw (not shown) composed of a bolt and a nut is screwed into the other end of the horizontal portion, and is brought into contact with the top end of the valve shaft of the other exhaust valve 2 so as to engage with the valve bridge 9 and to engage with the valve bridge 9. The height between the exhaust valves 1 and 2 is adjusted. The lower end portion 93a of the adjustable screw 93 provided at one end of the rocker arm 20 engages with the upper surface at the center of the horizontal portion (see FIG. 3). The rocker arm 20 has a central portion pivotally supported by a rocker shaft 21, and the other end is engaged with a valve operating cam 23 via a roller 22. That is, when the rocker arm 20 is swung by the lift force of the valve operating cam 23, the exhaust valves 1 and 2 are lifted via the valve bridge 9 according to the combustion cycle. A guide hole 26 having a lower end and an oil supply hole 25 at the upper end is formed in the central vertical portion 24 of the valve bridge 9. A guide shaft 28, whose lower end is fixed to a cylinder head 27 and stands upright, is inserted into the guide hole 26, and guides the vertical movement of the valve bridge 9 accompanying the valve driving. A block-like projection 29 for engaging with the transmission member 12 is formed on the upper portion of the central vertical portion 24 so as to bulge in a direction perpendicular to the horizontal portion.

As shown in FIG. 3, the release piston 5 has a substantially short cylindrical piston head 5a having a predetermined outer diameter.
And a shaft rod 5b coaxially extending below the piston head 5a. The lower end of the shaft rod 5b contacts the upper end of the transmission member 12. The transmission member 12 is formed of a substantially cylindrical rod body whose diameter is slightly reduced downward, and has a guide hole 30 opened at the lower end inside the rod member. A guide shaft 31 having a lower end fixed to the cylinder head 27 and standing upright is inserted into the guide hole 30, and guides the transmission member 12 in the vertical direction similarly to the valve bridge 9. A projection 32 protruding toward the valve bridge 9 is formed integrally with a side portion near the upper end of the transmission member 12 so as to contact the projection 29 of the valve bridge 9 from above. The lower end of the transmission member 12 is formed with a retainer portion 12a whose diameter is appropriately increased, and holds the upper end of a return spring 33 that urges upward. Protrusion 3
2 is provided with an oil supply hole 32a. The return spring 33 is provided between the return spring 33 and the upper surface of the cylinder head 27. That is, when the release piston 5 descends against the urging force of the return spring 33 and pushes down the transmission member 12, the transmission member 12 lowers the valve bridge 9, and the exhaust valve is independent of the rocking operation of the rocker arm 20. 1,2
Is opened by a predetermined minute amount L (for example, about 1.5 mm). The release piston housing 10 is formed of a block having a predetermined height, and a cylinder chamber 11 is formed in an upper portion 10a. The upper surface of the upper part 10 a is formed so as to be substantially aligned with the upper end of the rocker arm 20. The lower part 10b of the release piston housing 10
It is attached to the cylinder head 27 by bolts 34.

An adjusting screw 37 having a small piston 35 and a spring 36 therein is provided in the upper part of the cylinder chamber 11 so that the lower end of the small piston 35 contacts the upper surface of the release piston head 5a. I have. The upper limit of the release piston 5 is determined by the adjusting screw 37, and the stroke of the release piston 5 is adjusted so that the projections 29 and 32 always contact each other. By maintaining this constant contact (zero gap), the valve bridge 9 can be lifted integrally with the release piston 5 without mechanical impact. An oil escape hole 38 is formed in the release piston 5 from the upper surface of the head 5a to the peripheral side surface of the shaft rod 5b, and when the small piston 35 is in contact with the upper surface of the release piston head 5a, the oil escape hole 38 is formed. It is designed to close the opening. An oil passage 39 for guiding high-pressure hydraulic oil is connected to the cylinder chamber 11. The oil passage 39 extends from the inside of the release piston housing 10 to the inside of a cylindrical portion 40 protruding from the upper surface of the upper portion 10a. An attachment member 42 of a high-pressure pipe 41 that is appropriately bent and extended from the housing block 13 to be connected to the oil passage 39 is attached to the cylindrical portion 40.

Next, the hydraulic drive means 7 for appropriately operating the release piston 5 will be described. As shown in FIGS. 1 and 2, the hydraulic drive unit 7 includes a thick plate-shaped housing block 13 provided between the rocker arm 20 for the exhaust valve and the rocker arm 43 for the intake valve. A hydraulic pressure generating piston 44 for generating high hydraulic pressure in the circuit 6;
It is composed of a dedicated cam 45 for lifting the hydraulic pressure generating piston 44 at a predetermined timing. As shown in FIG. 4, the housing block 13 has a through hole 13 a through which the rocker shaft 21 passes, and the upper end of the block is formed so as to be substantially aligned with the upper ends of the rocker arms 20 and 43. The hydraulic circuit 6 includes the housing block 1
3 is formed in a substantially T-shape in a side view, one end of an upper path thereof communicates with the hydraulic control means 8 and the other end thereof communicates with a connector hole 46 formed in a horizontal direction in an upper part of the housing block 13. ing. This connector hole 4
6, a connector 47 having a shaft hole 47a is screwed into the flare nut 48 which is engaged with the end of the high-pressure pipe 41, as shown in FIGS. Is screwed. That is, the hydraulic circuit 6 and the cylinder chamber 11 of the release piston 5 are connected by the high-pressure pipe 41. A portion branched below the hydraulic circuit 6 communicates with a cylinder hole 49 formed in a lower portion of the housing block 13 to accommodate the hydraulic pressure generating piston 44.

The hydraulic pressure generating piston 44 has a cylinder hole 49.
, The lower end of which is extended from a cylinder hole 49, and a sliding portion 44a serving as a cam follower is formed at the extended end. A flange 50 is formed above the sliding portion 44a, and one end of a leaf spring 51 that urges upward is engaged. The other end of the leaf spring 51 extends along the lower surface of the housing block 13 and is attached by a vertical support bolt 52. A fixing bolt 53 for fixing the housing block 13 to the rocker shaft 21 is provided coaxially with the support bolt 52. When the hydraulic circuit 6 is not filled with the hydraulic oil, the leaf spring 51 moves the sliding portion 44 a of the hydraulic pressure generating piston 44 to the orbit 5 of the cam height portion 45 a of the dedicated cam 45.
4 and is held at a position away from it. When hydraulic oil is appropriately supplied to the hydraulic circuit 6, the hydraulic pressure generating piston 44 is lowered, and the sliding portion 44a is engaged with the special cam 45. The dedicated cam 45 is disposed between the valve operating cam 23 of the exhaust valves 1 and 2 and the valve operating cam 55 for driving the rocker arms 43 of the intake valves 3 and 4. Installed. The cam height portion 45a of the dedicated cam 45 is formed with a phase appropriately separated from the cam height portion 23a of the valve operating cam 23. That is, the hydraulic pressure generating piston 44 is driven at a time before and after the piston top dead center (during the compression / expansion stroke) preceding the lift in the exhaust stroke of the exhaust valves 1 and 2 during the combustion operation.

As shown in FIGS. 6 to 8, the hydraulic control means 8 is provided in a control spool valve 58 provided in an accommodation hole 57 in an upper portion of the housing block 13 and is provided inside the control spool valve 58. And a check valve 59. One end of the hydraulic circuit 6 communicates with the housing hole 57, and a hydraulic oil introduction passage 61 for introducing hydraulic oil communicates with a concave portion 60 formed on the bottom surface 57a.
The control spool valve 58 has a substantially cylindrical shape that can move up and down along the accommodation hole 57, and has a length slightly shorter than the accommodation hole 57. A spring 62 is provided above the control spool valve 58 and urges the control spool valve 58 in a direction to press the control spool valve 58 against the housing hole bottom surface 57a. The upper portion 58a of the control spool valve 58 is smaller in diameter than the accommodation hole 57, and the control spool valve 58 is connected to the accommodation hole bottom surface 57a.
In a state in which the hydraulic circuit 6 is lowered until it contacts the hydraulic circuit 6, the hydraulic circuit 6 communicates with the housing hole 57. A cover plate 63 for closing the opening is attached to the upper portion of the accommodation hole 57 with a bolt 64, and a relief hole 65 for opening one end of the control spool valve 58 to the atmosphere is formed. A radial communication hole 66 is formed in the longitudinal center of the control spool valve 58, and when the control spool valve 58 rises until it comes into contact with the cover plate 63, the check valve chamber 67 inside the valve body and the hydraulic pressure The communication with the circuit 6 is established. The check valve 59 is connected to the valve seat 6.
8 and a valve seat member 70 having a shaft hole 69, a check ball 71 seated on the valve seat 68 to close the shaft hole 69, and a spring 71a for pressing the check ball 71 against the valve seat 68.
And a retainer 72 for holding the spring 71a. The valve seat member 70 is fitted into the lower part of the valve body of the control spool valve 58, and the lower end of the shaft hole 69 is located
7a, the upper end is opened facing the check valve chamber 67, respectively. That is, when hydraulic oil of a predetermined pressure is supplied from the hydraulic oil introduction passage 61, the check ball 71 guides the hydraulic oil through the check valve chamber 67 to the hydraulic circuit 6, and a high hydraulic pressure is formed in the hydraulic circuit 6. Then, the check ball 71 is pressed against the valve seat 68 to close the shaft hole 69, so that the high oil pressure is maintained.

The operation switching means 14 includes a switching spool valve 74 housed in a vertical valve hole 73 formed in the side portion 13 b of the housing block 13, and a switching spool valve 7.
4 and an electromagnetic actuator 75 for appropriately operating the actuator. The housing side 13b is provided with a dedicated cam 4
5 is suspended in a stepped manner so as to surround the sides of the electromagnetic actuator 75, and the upper surface thereof is formed as a mounting seat for the main body 75 a of the electromagnetic actuator 75. As shown in FIG. 2, the housing side portion 13b has support portions 7 extending on both sides in the longitudinal direction of the engine.
6 are provided integrally, and the extending end thereof is attached to a camshaft bracket (not shown) by a bolt 77. The valve hole 73 is provided at its center in the height direction with the hydraulic oil introduction passage 61.
And a hydraulic oil supply passage 78 for replenishing hydraulic oil is connected to the upper part. The hydraulic oil supply path 78 is connected to the through hole 13 a of the rocker shaft 21. An oil line 79 connected to an oil gallery or the like is formed at the axial center position of the rocker shaft 21, and an oil supply passage 8 extending radially from the oil line 79.
0 communicates with the hydraulic oil supply passage 78. That is, the oil line 79 functions as a hydraulic oil supply source. Note that the oil line 79 is provided with a valve operating lubricating oil passage 90 for supplying lubricating oil to the rocker arms 20 and 43.

The switching spool valve 74 is connected to the hydraulic oil supply path 7.
8 has a shaft hole 81 opened downward to communicate with the hydraulic fluid passage 8 and a reduced-diameter portion 82 communicating with the hydraulic oil introduction passage 61 so that these hydraulic oil passages (78, 61) are appropriately communicated and blocked. Is formed. A spring 83 for urging upward is provided on the lower end opening side of the shaft hole 81. This spring 83
Is supported by a plug body 85 having a relief hole 84 for releasing hydraulic oil to the atmosphere. The electromagnetic actuator 75 includes an advance / retreat rod 86 that can move in and out along the axis of the main body 75a, and a solenoid 87 for operating the advance / retreat rod 86. The solenoid 87 is excited by an operation command from a controller (microcomputer) 88. By doing so, the reciprocating rod 86 is lowered. That is, when the switching spool valve 74 is pushed by the advance / retreat rod 86,
The hydraulic pressure for turning on the operation is sent to the hydraulic control means 8 through the hydraulic oil introduction path 61, and the peripheral surface reduced diameter portion 82 is connected to the hydraulic oil supply path 7.
This oil pressure is maintained by engaging with the opening 8. When the electromagnetic actuator 75 is not operating, the switching spool valve 74 is located above the opening of the hydraulic oil introduction passage 61, and the hydraulic oil introduction passage 61 is connected to the valve hole 7.
3 communicates with it.

As shown in FIG. 9, the controller 88 comprises:
ON / OFF operation switch 89 provided in the driver's seat
The engine brake device can be switched to a mode of operation or non-operation by sensing the coolant temperature, the engine speed, the loaded weight, the vehicle speed, etc., and based on these detected values, each cylinder C according to the process output processing program. An operation signal is output to the electromagnetic actuator 75 of the first embodiment. In FIG. 9, the cylinders No. 1 and No. 3 of the engine are in operation OFF, and the cylinders No. 2 and No. 4 are in operation ON.

In addition, the rocker arms 20 and 43 include
As shown in FIG. 5, two oil passages 91 and 92 communicating with the valve operating lubricating oil passage 90 of the rocker shaft 21 are formed. One of the oil passages 91 is the rocker arm 2
0, 43, the adjustable screw 9
3 communicates with a screw hole 94 into which the screw 3 is screwed. The other oil passage 92 extends to the other end of the rocker arms 20 and 43, and is provided with a support hole 95 for the roller 22 that engages with the valve operating cams 23 and 55.
Is in communication with At the ends of these oil passages 91 and 92, there are provided oil amount chokes 96 and 96 for securing appropriate lubricating oil pressure.
97 are provided. Further, as shown in FIG. 1, the cylinder head 27 is provided with a cylinder head cover 98 having a substantially rectangular cross section which covers above the housing block 13 and the valve mechanism (rocker arms 20, 43).

When the running brake of the vehicle is performed by the engine brake device configured as described above, the operation switch 89 is set to "ON" by the driver's intention to increase the braking force during engine braking. Then, the controller 88 outputs an operation command to the electromagnetic actuator 75 of each cylinder C according to the operating condition. For example, if a large engine braking force is required, all cylinders C
Is activated, and if it is sufficient to partially increase the engine braking force, an appropriate number of all cylinders C is selected. That is, in the case of a four-cylinder engine, the braking force can be varied in five stages including the operation OFF.

The electromagnetic actuator 75 of the cylinder C, which has received the operation command, lowers the switching spool valve 74 by projecting the reciprocating rod 86, and removes the hydraulic oil in the valve hole 73 (operating hydraulic oil). It is sent to the accommodation hole 57 of the hydraulic control means 8 through the hydraulic oil introduction path 61 (see FIG. 7). By this operating oil pressure, the control spool valve 58 rises and the check valve chamber 6
The hydraulic oil is filled in the hydraulic circuit 6 through the switch 7. When the hydraulic pressure of the hydraulic circuit 6 reaches a predetermined pressure, the hydraulic pressure generating piston 44 descends against the leaf spring 51 and engages with the basic circular portion of the special cam 45. In this state, the dedicated cam 45 that follows the rotation of the camshaft 56 has its cam height 4
The hydraulic pressure generating piston 44 is lifted by 5a to generate high hydraulic pressure in the hydraulic circuit 6 (see FIG. 8). This high oil pressure acts on the release piston head 5a in the cylinder chamber 11 via the high-pressure pipe 41, and the release piston 5 is pushed down. When the release piston 5 is depressed, the shaft rod 5b lowers the transmission member 12, and the projection 32 comes into contact with the projection 29 of the valve bridge 9 and moves it downward. According to this movement, the exhaust valves 1 and 2 are set to a predetermined minute amount L
The compression pressure is released from the cylinder C near the piston top dead center. As a result, the expansion pressure becomes lower than the compression pressure, and the piston of the engine running by inertia is decelerated by increasing the negative work. That is, a large engine brake can be obtained by rapidly releasing the compressed pressure of the intake air as it is to the exhaust system.

When the driving condition changes, the engine brake does not need to be increased, and the operation switch 58 is set to "O".
When “FF” is set, the reciprocating rod 86 of the electromagnetic actuator 75 is immersed in the main body 75 a, and the switching spool valve 74 is raised by the urging force of the spring 83. As a result, the hydraulic oil below the housing hole 57 is released to the atmosphere from the relief hole 84 of the plug body 85 through the hydraulic oil introduction passage 61 and the valve hole 73, and the control spool valve 58 is lowered by the urging force of the spring 62. . Due to this lowering, the atmosphere opening hole 100 of the control spool valve 58 is in communication with the hydraulic circuit 6, the hydraulic oil is no longer supplied through the check valve 59, and the hydraulic circuit 6 is in a reduced pressure state. With this, the hydraulic pressure generating piston 44
Is raised by the leaf spring 51 to a position where it does not engage with the dedicated cam 45, and the release piston 5 is also raised to be maintained at a position that achieves the aforementioned zero gap.

As described above, each of the cylinders C containing the hydraulic circuit 6 of the hydraulic drive means 7 for driving the release piston 5
Since the operation switching means 14 for switching between operation and non-operation is provided in the housing block 13, a hydraulic oil introduction passage 61 for supplying hydraulic oil to the hydraulic circuit 6 can be formed in the housing block 13. This eliminates the need for complicated piping, thereby reducing the number of assembly steps and cost. Since the housing block 13 is provided on the rocker shaft 21 and the hydraulic oil supply passage 78 is also formed inside the housing block 13, the oil line 79 for lubricating the valve mechanism can be used for replenishing the hydraulic oil. The number of pipes can be further reduced. The operation switching means 14 is composed of the electromagnetic actuator 75 and the switching spool valve 74, and the operation start / end is controlled by the controller 88, so that the number of cylinders C for operating the release piston 5 can be adjusted. In addition, it is possible to automatically increase the optimum engine braking force according to the load weight and the vehicle speed.

In this embodiment, the release piston 5
Is transmitted to the valve bridge 9 via the transmission member 12, and the release piston 5 is arranged so as not to protrude above the rocker arm 21, so that the overall height of the engine does not increase and the vehicle is mounted on the vehicle. In addition to eliminating the height limitation, compactness of the entire engine and improvement in versatility are achieved. Since the release piston 5 is offset from the valve bridge 9 and the rocker arm 21, there is no need to remove the release piston housing 10 and the housing block 13 or the release piston 5 when adjusting the adjustable screw 93, and the like.
Workability of the valve clearance adjustment operation is improved. Further, since the projection 32 of the transmission member 12 and the projection 29 of the valve bridge 9 are engaged with zero gap, the release piston 5 and the valve bridge 9 can be engaged according to the ramp curve of the cam profile.
The mechanical shock between them can be minimized, and the durability reliability can be improved. That is, FIG.
As shown in (b), when the gap G is not 0, for example, when G = 0.8 mm, the cam height portion 4 of the special cam 45
At the time of engagement with 5a, the release piston 5 is rapidly driven to generate a striking sound. However, as shown in FIG. 10 (a), if G = 0, the release piston 5 smoothly moves according to the cam profile. Is to be lifted. Therefore, in a configuration in which the exclusive piston 45 drives the release piston 5 by generating a high oil pressure, durability and impact noise can be improved.

When the release piston 5 is operated, the guide shafts 28, 31 and the valve bridge 9 and the transmission member 1 are operated.
Although a high side force is instantaneously generated between the second member and the second member, the durability can be maintained by taking measures such as surface treatment of the member and material selection. In the above embodiment,
Although a four-valve, four-cylinder engine has been exemplified, the present invention is not limited to this, but is widely applied to all types of engines.

[0024]

In summary, according to the present invention, the piping for supplying the hydraulic oil to the hydraulic circuit of the hydraulic drive means can be simplified, the cost can be reduced and the assemblability can be improved. Since activation / deactivation can be controlled for each cylinder, the increase in engine braking force can be made variable according to the driving situation.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an embodiment of an engine brake device according to the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a side sectional view showing a main part of FIG. 1;

FIG. 4 is a plan view showing a main part of FIG. 2;

FIG. 5 is a view showing the rocker shaft of FIG. 1;
(A) is a plan view and (b) is a side view.

FIG. 6 is a side sectional view showing a main part of FIG. 1;

FIG. 7 is a side sectional view for explaining the operation of FIG. 6;

FIG. 8 is a side sectional view for explaining another operation of FIG. 6;

FIG. 9 is a block diagram for explaining the operation of the engine brake device of FIG. 1;

FIG. 10 is a relationship diagram between a lift and a crank rotation angle for explaining the operation of the transmission member of FIG. 3;

[Explanation of symbols]

 1, 2 Exhaust valve 5 Release piston 6 Hydraulic circuit 7 Hydraulic driving means 8 Hydraulic control means 13 Housing block (housing) 14 Operation switching means 20, 43 Rocker arm (valve mechanism) 21 Rocker shaft 61 Hydraulic oil introduction path (Hydraulic oil) Path) 74 Spool valve for switching 75 Electromagnetic actuator 78 Hydraulic oil supply path (hydraulic oil path) 79 Oil line (hydraulic oil supply source) 88 Controller 90 Lubricating oil path for valve C C cylinder

Claims (3)

[Claims] 1. A release piston for lifting an exhaust valve of each cylinder to appropriately release a compression pressure, a hydraulic drive means for generating a high oil pressure in a hydraulic circuit to drive the release piston, and Hydraulic control means for appropriately guiding the operating hydraulic pressure to the hydraulic circuit to control the hydraulic pressure to a state in which a predetermined high hydraulic pressure can be formed, and operating the hydraulic control means in a housing of the hydraulic circuit provided for each cylinder. An engine brake device comprising an operation switching means for switching between operation and non-operation by supplying and discharging hydraulic pressure. 2. The operation switching means, wherein a switching spool valve for communicating or shutting off a hydraulic oil passage connecting a hydraulic oil supply source and the hydraulic control means, and operating the switching spool valve in accordance with an operating condition. 2. The engine brake device according to claim 1, further comprising an electromagnetic actuator for driving. 3. The engine brake device according to claim 2, wherein the hydraulic oil supply source has a valve operating lubricating oil passage for supplying lubricating oil to the valve operating mechanism.