JP2001098912A - Engine brake device and method of controlling it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a brake unit compact, to reduce the cost and to ensure the reliable durability. SOLUTION: In an engine brake device, an actuator piston 4, a check ball 5 and a change-over plunger 6 which are laid along and coaxially with a predetermined reference axis C, are all accommodated in an actuator body 7 which is formed on its outer peripheral part with a male thread 8 coaxial with the reference axis so as to be threadedly engaged with a stationary side unit body 9 in order to constitute a brake unit 1 for each engine cylinder. Since the components in the actuator body 7 are uniaxially arranged along the reference axis C so as to make the brake unit compact, and accordingly, drilling can be simplified, thereby it is possible to reduce the cost.

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 which releases a compression pressure when an engine brake is used to increase an engine braking force, and a control method thereof.

[0002]

2. Description of the Related Art There are a synchronous type and a normally open type of this type of engine brake device, and the present applicant has previously proposed a normally open type. Here, the normally open type means that the exhaust valve is opened at least slightly during the entire stroke of the engine.

[0003]

[Problems to be Solved by the Invention] Japanese Patent Application No. 7-231516 (hereinafter referred to as "first prior application") and Japanese Patent Application No. 8-31 are filed by the present applicant.
No. 0598 (hereinafter referred to as "second prior application"). Each of these has a hydraulically operated brake unit for each cylinder,
Each brake unit is turned on / off by a common solenoid valve unit.

When assembling the brake unit to the engine, the gap between the output shaft end of the brake unit and the shaft end on the exhaust valve side must be set to a predetermined constant value. Otherwise, the exhaust valve cannot be opened at an accurate timing and lift amount. However, in practice, there are variations among individuals due to manufacturing errors and assembly errors. Therefore, a mechanism for finely adjusting the gap for each individual exists in any prior application.

In the first prior application, a lock nut is provided at the lower end of the brake unit, and the gap can be finely adjusted by loosening or tightening the lock nut. However, various valve operating parts, such as rocker arms, exist around it, and there is interference with them, so that the work is very complicated.

Therefore, in the second prior application, a lock nut is provided on the top of the brake unit so that the work can be easily performed from above.

However, the second prior application also has the following problems. In other words, in this case, when hydraulic pressure is supplied to the brake unit, the check ball opens to send hydraulic pressure to the piston chamber, lowering the piston in the exhaust valve opening direction, and closing the piston so that the maximum downward movement follows the piston. It was defined by the stroke of the member. When the piston descends beyond the maximum descending amount, the closing member separates from the piston, a leak hole provided in the piston opens, hydraulic pressure escapes, and the descending of the piston stops.

However, according to this method, the piston moves up and down near the maximum lowering position, and the opening and closing of the leak hole is repeated, and the internal pressure of the piston chamber is slightly vibrated. Sex was getting worse.

Incidentally, such a maximum lift automatic adjustment mechanism is not employed in the first prior application. Therefore, the first prior application does not have such a problem.

Next, in any of the prior applications, the piston and the piston chamber are arranged coaxially with the exhaust valve shaft, while the check ball and the switching plunger for switching between hydraulic supply and discharge before the piston chamber are not coaxial with the exhaust valve shaft. Was. In the first prior application, it was arranged parallel to another place, and in the second prior application, it was arranged in the orthogonal direction. For this reason, the brake unit had to be relatively large in the prior application. Further, in such a multi-axis arrangement, the holes for accommodating the respective parts must be processed in a multi-axis manner, which makes the processing complicated and costly.

An object of the present invention is to provide an engine brake device which can solve the disadvantages without losing the advantages of the prior application.

It is another object of the present invention to provide an engine brake device in which fine adjustment of a gap is easy.

Another object of the present invention is to provide an engine brake device capable of ensuring the durability of a check ball.

Another object of the present invention is to provide an engine brake device having a compact and low-cost brake unit.

It is another object of the present invention to provide an engine brake device having high reliability and durability.

It is a further object of the present invention to provide a method of controlling an engine brake device which can obtain a high engine braking force.

[0017]

In the engine brake device according to the present invention, an actuator piston, a check ball and a switching plunger are arranged coaxially with a predetermined reference axis, and these are collectively arranged on an actuator body. A male screw coaxial with the reference axis is provided on the outer peripheral portion of the actuator body, and the actuator body is screwed to a unit body on the fixed side to form a brake unit for each cylinder.

According to this configuration, the brake unit can be made compact because it is uniaxially arranged along the reference axis. In addition, the processing of the holes is facilitated and the cost is reduced.

Preferably, the reference axis is located coaxially with the exhaust valve of the engine.

It is preferable that a male screw of the actuator body projects above the unit body, and a lock nut is fastened to the projection to fix a relative position between the actuator body and the unit body.

It is preferable that the actuator body is provided with a pair of stopper portions which come into contact with the actuator piston and regulate the amount of movement thereof within a predetermined range.

It is preferable that a working fluid passage is formed in a threaded portion between the actuator body and the unit body.

It is preferable that the unit bodies for a plurality of cylinders are connected to each other to form a connection unit body, and a fluid passage for supplying and discharging working fluid to and from a brake unit for each cylinder is provided inside the connection unit body. .

It is preferable that the connecting unit body is supported on both sides of the cylinder head of the engine.

A frame-shaped casing attached to an upper portion of an engine cylinder head and having the same shape as the cylinder head;
It is preferable that an electromagnetic valve unit for switching the supply and discharge of the working fluid to and from the brake unit be attached to an outer portion of the casing.

The solenoid valve unit is mounted at an intermediate position in the longitudinal direction of the casing, and the unit bodies for the front and rear cylinders are connected to each other at the position to form a connection unit body. It is preferable that each of the above-mentioned solenoid valve units is connected by a pipe.

The present engine brake device is preferably used in combination with an exhaust brake device.

As a control method in this case, the operation and non-operation of the engine brake device and the exhaust brake device are switched according to the ON / OFF of the manual switch and the engine speed. If the number is less than a predetermined value, the engine brake device is inactivated, if the engine speed is equal to or greater than the predetermined value, the engine brake device is activated, and the exhaust brake device is activated at all engine speeds. Is preferred.

[0029]

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

As shown in FIGS. 4 and 5, the engine brake device according to the present invention is a normally-open type, and includes a brake unit 1 provided for each cylinder of the engine and a fluid It mainly comprises an electromagnetic valve unit 2 for switching between supply and discharge of pressure. Here, the engine is an in-line four-cylinder diesel engine. In such an engine brake device, the lubricating oil of the engine is used as a working fluid, and a sufficiently high-pressure oil is taken out from a position immediately after an oil pump (not shown) outlet, and the oil is taken out of the solenoid valve unit 2,
The exhaust gas is sent to the brake unit 1 in order, and the exhaust valve 3 is opened. Thus, the brake unit 1
Functions as a hydraulically actuated actuator.

As shown in FIGS. 1 and 2, in the brake unit 1, an actuator piston 4, a check ball 5, and a switching plunger 6 are arranged coaxially with a predetermined reference axis C. These are all housed together in the actuator body 7, and a male screw 8 coaxial with the reference axis C is provided on the outer peripheral portion of the actuator body 7. Then, the actuator unit 7 is screwed into the unit body 9 on the fixed side to thereby form the brake unit 1.
Is roughly configured.

The brake unit 1 is located above the exhaust valve 3, and houses the actuator piston 4, the check ball 5, and the switching plunger 6 in order from below. The reference axis C is located coaxially with the exhaust valve 3. The unit body 9 is mounted on a cylinder head 75 of the engine, and has an actuator body mounting hole 10 penetrating vertically. The upper part of the hole 10 is a female screw hole 11, and the lower part is a large-diameter sliding hole 12. A male screw 8 formed on the upper outer periphery of the actuator body 7 is screwed into the female screw hole 11, and the actuator body 7 is inserted into the large-diameter sliding hole 12.
The large-diameter sliding portion 13 formed on the outer periphery of the lower part of the first member is slidably inserted. The actuator body mounting hole 10 is also coaxial with the reference axis C.

The actuator body 7 has a stepped cylindrical shape centered on the reference axis C, and has a large-diameter piston receiving hole 14 at the lower portion, a check ball receiving hole 15 at the intermediate portion, and a switching plunger at the upper portion. The receiving holes 16 are formed coaxially with the reference axis C, respectively. The check ball receiving hole 15 and the switching plunger receiving hole 16 communicate with each other through a hydraulic supply / discharge port 17 coaxial with the reference axis C.

The actuator piston 4 is slidably inserted into the piston receiving hole 14. The actuator piston 4 integrally has an output shaft 18 at the center thereof.
The piston spring 19 is housed on the outer periphery of the piston. The piston spring 19 urges the actuator piston 4 upward. A ring-shaped piston spring seat 20 and a snap ring 21 are engaged with and attached to the lower ends of the piston receiving holes 14, respectively.

The actuator piston 4 can move up and down along the reference axis C.
A pair of stopper portions are provided which come into contact with the actuator piston 4 and regulate the movement amount (elevation amount) within a predetermined range. The upper stopper portion is the upper end wall 2 of the piston receiving hole 14.
2 and the lower stopper portion is made of a piston spring seat 20. The actuator piston 4 comes into contact with these stopper portions, and the ascent and descent are regulated.

A cup-shaped ball retainer 23 is fixed in the check ball receiving hole 15, and the check ball 5 is provided therein so as to be able to move up and down slightly. In the ball retainer 23, the check ball 5 is provided with the upper hydraulic supply / drain 1
A ball spring 24 for urging toward the 7 side is also provided. The ball retainer 23 has a structure that allows oil to pass through.

The switching plunger 6 is inserted into the switching plunger receiving hole 16 so as to be slidable up and down. The switching plunger 6 has a push pin 25 integrally at the lower end. The push pin 25 can be inserted through the oil supply / drain port 17 with a gap to push down the check ball 5. The switching plunger 6 has a cylindrical portion 26 opened upward and accommodates a plunger spring 27 therein. The plunger spring 27 urges the switching plunger 6 downward. A plunger spring seat 28 and a snap ring 29 are engaged with and mounted on the upper end of the switching plunger housing hole 16. When the switching plunger 6 comes into contact with the plunger spring seat 28, its rise is regulated, and when it comes into contact with the stepped reduced diameter portion 30 of the switching plunger housing hole 16, its descending is regulated.

The step-like reduced diameter portion 3 is provided below the switching plunger 6.
A switching hydraulic chamber 31 defined by 0 is formed, and a high-pressure hydraulic chamber 32 defined by the piston housing hole 14 and the check ball housing hole 15 is formed above the actuator piston 4. The switching hydraulic chamber 31 and the high-pressure hydraulic chamber 32 communicate with each other through the hydraulic supply / discharge port 17.

An oil first passage 33 orthogonal to the reference axis C is provided inside the unit body 9, and the oil first passage 33 and the switching hydraulic chamber 31 extend from the oil first passage 33 in an orthogonal direction. It is communicated with the second passage 34. In particular, an intermediate portion of the oil second passage 34 is formed at a threaded portion between the actuator body 7 and the unit body 9. That is, a groove 35 is provided in the male screw 8 of the actuator body 7 along the direction of the reference axis C.
And part of it. Reference numeral 36 denotes a blind ball that closes a processing hole of the second oil passage 34.

As described above, the unit body 9 includes the portion surrounding the actuator body 7 and the oil first passage 33.
And a part surrounding the. Here, the upper end of the male screw 8 of the actuator body 7 protrudes upward from the unit body 9, and a lock nut 37 is fastened to this protruding portion to fix the relative position between the actuator body 7 and the unit body 9. A slit 38 for tool engagement is provided on the upper end surface of the male screw 8.

In the brake unit 1, the switching hydraulic chamber 31 is switched through the first oil passage 33 and the second oil passage 34.
When the high-pressure oil is introduced into the pump, the switching plunger 6 is raised by this hydraulic pressure, the check ball 5 is pushed down, and the oil supply / discharge port 17 is opened. Then, high-pressure oil is introduced into the high-pressure hydraulic chamber 32 and presses the actuator piston 4 downward. When the pressure in the high-pressure hydraulic chamber 32 reaches a constant high pressure, the check ball 5 is
To close the oil supply / drain opening 17.

On the other hand, when high-pressure oil is discharged from the switching hydraulic chamber 31 through the oil first passage 33 and the oil second passage 34, the switching plunger 6
And the switching plunger 6 pushes down the check ball 5. Then, the oil supply / discharge port 17 is opened, and the high-pressure oil in the high-pressure hydraulic chamber 32 leaks to the switching hydraulic chamber 31, the oil second passage 34, and the oil first passage 33,
The hydraulic pressure in the high-pressure hydraulic chamber 32 decreases. When this happens, the actuator piston 4 rises.

As shown in FIG. 1, the engine is provided with two exhaust valves 3 per cylinder. These exhaust valves 3 need to be lifted simultaneously at regular valve timing. For this purpose, the engine is provided with a valve spring 40, a valve bridge 41, a rocker arm 42 and a camshaft 39.

In this device, the exhaust valve lift by the actuator piston 4 and the exhaust valve lift by the cam sometimes interfere. For this reason, the cam lift is prioritized by the following configuration.

That is, the push rod 43 is
The sleeve 44 is screwed into the valve bridge 41 in a vertically penetrating state, and fixed with a nut 45. At the time of a regular cam lift, the valve bridge 41 and the sleeve 44 simultaneously lower, and the sleeve 44 engages with the umbrella portion 46 at the lower end of the push rod to push down the push rod 43. As a result, the exhaust valve 3 is lifted relatively large. On the other hand, when the actuator piston 4 lifts during braking, the actuator piston 4 pushes down the push rod 43 while relatively moving the push rod 43 with respect to the sleeve 44. Thus, the exhaust valve 3 pushed by the push rod 43 is slightly lifted. Since the cam lift amount of the exhaust valve 3 is larger than the lift amount at the time of braking, when the lifts interfere with each other, the regular cam lift takes precedence, and the actuator piston 4 and the push rod 43 are relatively far apart.

As shown in FIG. 2, when the exhaust valve 3 is also closed when the engine brake device is not operating, the shaft end of the output shaft 18 of the actuator piston 4 and the shaft end of the push rod 43 are connected. There is a slight gap G between them. Depending on the size of the gap G, the exhaust valve lift timing and the lift amount during braking slightly change. For this reason, when assembling the brake unit 1 to the engine, the gap G
Must be set to a predetermined constant value. In this device, fine adjustment at this time is very easy.

That is, loosen the lock nut 37 from above,
A tool is engaged with the slit 38 from above to rotate the actuator body 7, the actuator piston 4 is moved up and down together with the actuator body 7, the gap G is adjusted to a desired value, and then the lock nut 37 is tightened.
Since the work can be performed from above without any interference, the work is very easy.

As shown in FIGS. 4 and 5, in the present apparatus, the unit bodies 9 for two cylinders are integrally connected to form a connection unit body 47 before and after the longitudinal direction of the engine. It is mounted on the boss 77 on the cylinder head by the bolts 48 and fixed while being supported at both ends. On the other hand, a frame-like casing 49 of the same shape is attached to the upper part of the cylinder head, and the solenoid valve unit 2 is attached to the front and rear intermediate position of the casing 49 and to the outside. The oil outlet 54 of the solenoid valve unit 2 and each connection unit body 47 are connected by an oil pipe 50, respectively. The oil first passage 33 is provided inside the connection unit body 47 along the longitudinal direction thereof, so that oil can be supplied to and discharged from the brake unit 1 of each cylinder.

As shown in FIG. 3, the solenoid valve unit 2
Oil inlet 5 consisting of eye 51 and eye bolt 52
3 and an outlet 54. High pressure oil is constantly supplied to the inlet 53 from an oil pump. The outlet portion 54 is connected to the oil pipe 50, and the connection unit body 47
(Ie, each cylinder brake unit 1) is supplied and discharged with high-pressure oil. Reference numeral 55 denotes a nipple for discharging the oil returned to the outlet 54 to the oil pan side.

The solenoid valve unit 2 has a valve body 56 and a coil case 57 coaxially mounted on the valve body 56. A coil 58 is accommodated in the coil case 57, and the plunger 59 is advanced and retracted in the axial direction according to ON / OFF of the coil 58. In accordance with this, the spool valve 60 in the valve body 56 advances and retreats in the axial direction. The spool valve 60 is slidably housed in a valve case 61 coaxially fitted in the valve body 56. A return spring 62 for urging the spool valve 60 toward the plunger 59 is provided in the valve case 61. Entrance part 5
Oil inlet hole 63 and oil outlet hole 64 penetrating the valve case 61 at the axial positions of the outlet 3 and the outlet 54, respectively.
Is provided. A reduced diameter passage 65 for selectively communicating the oil inlet hole 63 and the outlet hole 64 with each other is provided on the outer periphery of the spool valve 60. An oil discharge hole 66 is provided at the end of the valve case 61.

When the coil is OFF as shown in FIG. 3, the plunger 59 and the spool valve 60 are in the retracted position, and the oil inlet hole 63 and the oil outlet hole 64 are shut off. As a result, the oil supplied to the inlet 53 is supplied to the reduced diameter passage 65.
And is not reached to the outlet 54. At this time, the spool valve 60 has half opened the oil outlet hole 64. Therefore, if high-pressure oil has already been supplied to the brake unit 1, the high-pressure oil flows backward, reaches the oil outlet hole 64 and the oil discharge hole 66, and is discharged from the nipple 55. This discharged oil is returned to the oil pan.

On the other hand, when the coil 58 is turned on from this state, the plunger 59 and the spool valve 60 are protruded (moved to the left in the drawing), and the oil inlet hole 63 and the oil outlet hole 64 are communicated. As a result, the high-pressure oil waiting in the reduced-diameter passage 65 is transferred to the oil outlet hole 64 and the outlet 5.
4 to each brake unit 1. As a result, the actuator piston 4 is driven in each brake unit 1, and the minute lift of the exhaust valve 3 is performed.

As shown in FIG. 4, the coil 58 is ON / OFF controlled by an electronic control unit (hereinafter referred to as "ECU") 67. The ECU 67 generally controls the electronic control of the engine and the vehicle, and takes in various signals indicating the engine operating state and the vehicle running state, such as the engine speed and the TDC signal of each cylinder.

FIG. 6 shows a cycle diagram when the present apparatus is operated. When the coil 58 is turned on as described above, the actuator piston 4 is pushed downward by high-pressure oil. At this time, if the exhaust valve 3 has already been lowered at the regular valve timing, the actuator piston 4 will be lowered. Thereafter, when the exhaust valve 3 rises at regular valve timing, the push rod 43 simultaneously rises and comes into contact with the output shaft 18 of the actuator piston 4. Thereby, as shown in FIG. 1, the exhaust valve 3 is slightly lifted (about 1 mm) with respect to the valve seat 76, and is prevented from being fully closed. Thereafter, at least this minute lift state is maintained over the entire cycle, and the lift is performed with a regular cam lift amount when the regular valve opening period is reached.

The high-pressure oil for driving the actuator piston 4 is a system oil pressure and not so high. Therefore, there is not enough force to push down the exhaust valve 3 against the urging force of the valve spring 40. Therefore, the actuator piston 4 is lowered at the same time as or after the exhaust valve 3 is lowered, and the exhaust valve 3 to be raised is stopped immediately before closing. There is not enough force to push down the exhaust valve 3, but there is enough force to stop the exhaust valve 3 once opened. Conversely, a minute lift of the exhaust valve 3 can be achieved using a system hydraulic pressure that is not so high, so that a hydraulic circuit need not be configured in a separate system, and simplification of the structure and cost reduction can be achieved.

Thus, the coil ON timing can be set relatively freely. This is because the supply of hydraulic pressure to the actuator piston 4 due to the coil ON does not directly lead to the lift of the exhaust valve 3.

As shown in FIG. 4, the present engine brake device is used in combination with the exhaust brake device 68 here. The exhaust brake device 68 is provided with an exhaust shutter 69 at an outlet portion or a collecting portion of the exhaust manifold 71, and the exhaust shutter 69 is selectively opened and closed by a pneumatically operated servo device 70. A servo pressure valve 71 is provided in a pneumatic supply pipe leading to the servo device 70.
Is turned on / off by the ECU 67 to perform exhaust brake control.

The operation and the non-operation of the present device and the exhaust brake device 68 are switched in accordance with ON / OFF of a manual switch 72 provided in the vehicle interior. However, as shown in FIG. 7, even if the manual switch 72 is ON, the operation state of this device is switched according to the engine speed. The switching based on the rotation speed is performed by the ECU 67. This device is activated only when the engine speed is equal to or higher than a predetermined switching speed N, and is deactivated when it is lower than the switching speed N. The switching speed N is a relatively low speed, for example, 15
00 (rpm) is set. On the other hand, the exhaust brake device 68
Are activated at all engine speeds.
As a result, when the switching speed is less than N, the exhaust brake device 68 operates alone (shown by a diamond in the figure), and the switching speed N
In this case, the present device and the exhaust brake device 68 are simultaneously operated (indicated by a circle in the figure).

This engine brake device has the following features. That is, the actuator piston 4, the check ball 5, and the switching plunger 6
And the actuator body 7 is screwed to the unit body 9 to form a so-called floating body structure, so that the configuration of the brake unit 1 is very compact, and drilling holes in the actuator body 7 and the unit body 9 Also, coaxial processing becomes very easy. As a result, a highly accurate brake unit can be manufactured at low cost.

Further, the adjustment of the gap G is very easy since it can be performed from above. At this time, the actuator body 7
Is rotated to move the actuator piston 4 up and down, so that work from above can be easily performed. Even if the actuator body 7 is rotated, the actuator piston 4 does not become misaligned. This is because the actuator piston 4 and the male screw 8 of the actuator body 7 are coaxial with the reference axis C. As a result, during the rotation of the actuator body 7, the coaxiality between the actuator piston 4 and the exhaust valve 3 is maintained even if the actuator piston 4 causes relative slippage in the rotation direction.

Further, since a part of the oil second passage 34 is formed in the threaded portion between the actuator body 7 and the unit body 9, the processing of the oil second passage 34 is easy. That is, it is only necessary to provide the groove 35 on the outer peripheral portion of the male screw 8 as in the present embodiment. By doing so, even if the actuator body 7 is moved up and down for fine adjustment of the gap,
The communication state is maintained without the passage being cut off.

Further, since the maximum lift automatic adjustment mechanism as in the second prior application is not employed, the reliability and durability of the check ball 5 can be ensured.

In this apparatus, the unit body 9 for two cylinders is connected to form a connection unit body 47, which is supported at both ends. Therefore, the mounting rigidity is higher than that of the cantilever support as in the prior application, and the vibration is higher. Is suppressed. Also, since the common oil first passage 33 can be made in the connection unit body 47,
There is no need to provide oil piping for each cylinder brake unit as in the prior application. As a result, it is not necessary to use a long pipe and cracks due to vibration are not generated, which is very advantageous in terms of reliability and durability. This apparatus uses only two short oil pipes 50 as shown in FIG. In particular, in the configuration of the present apparatus in which the solenoid valve unit 2 is laid out between the front and rear connection unit bodies 47, the oil piping 50 is shortest. Note that the connection unit body 47 may be a multi-cylinder one.

As shown in FIG. 5, in this apparatus, a frame-shaped casing 49 is separately provided, and the electromagnetic valve unit 2 is attached to the outside of the casing. For this reason, mounting work and maintenance become easy. In this case, the valve body 56 of the solenoid valve unit 2 and the casing 49 can be integrated, which is advantageous for cost reduction. In FIG. 5, the oil outlet 54 is provided below the casing 49 and does not appear in the drawing.

Incidentally, the control method of the present apparatus shown in FIG. 7 has the following advantages. In other words, the present device makes the exhaust valve 3 minutely lift and creates a choke state around the exhaust valve to generate a braking force. For this reason, if the engine speed is too low, the in-cylinder compression pressure simply escapes, and no choke occurs, and no braking force is generated. Therefore, in the low rotation range, the exhaust brake is performed by the exhaust brake device 68 alone. In the exhaust brake device 68, a low-speed exhaust shutter having an exhaust throttle stronger than usual is used as the exhaust shutter 69. That is, a shutter that defines an exhaust passage area equivalent to a hole having a diameter of 4 mm when the shutter is fully closed is used as the exhaust shutter 69. Normal exhaust shutter has a diameter of 8
It is equivalent to a hole of mm. As a result, an exhaust braking force higher than usual can be obtained in a low rotation range.

On the other hand, when the exhaust throttle is strengthened in this way, if the apparatus is not operated at the same time, the exhaust pressure in the section from the exhaust valve 3 to the exhaust shutter 69 becomes abnormally large in the middle and high rotation range, and the exhaust valve 3 Bounces and the like are caused, and the engine is damaged at worst. Here, since the present apparatus is operated at the same time, the exhaust gas in the above section is sucked by flowing backward in the cylinder in the intake stroke, thereby reducing the exhaust pressure. As a result, it is possible to generate a compression brake force by forming a choke around the exhaust valve while securing the exhaust brake force even in the middle and high speed range. As a result, a high braking force can be obtained even in the middle and high speed range.

This advantage is obtained only because the engine brake device is of the normally open type. This is specifically shown below. First, FIG. 8 shows a case where the exhaust brake device is operated alone. By closing the exhaust shutter 69, P ₁ = 5 in the exhaust passage section 80 from each exhaust valve 3 to the exhaust shutter 69.
(kg / cm ² ). At this time, an exhaust braking force is generated at _{No. 1} cyl in the exhaust stroke by the pressure P1. The exhaust brake force is larger the higher the pressure P _1.

On the other hand, No. 2cyl is in the intake stroke (intake pressure P ₂ ), and at this time, the exhaust valve 3 of the cylinder concerned has the umbrella back 3a.
It pushed in the opening direction by the pressure P ₁ from. Assuming that the pressure receiving area of the umbrella section back surface 3a is S, a force P ₁ S in the valve opening direction is applied to the exhaust valve 3 if the in-cylinder pressure is ignored. If this is less than the set load F of the valve spring 40, the exhaust valve 3 can be closed, but if it exceeds F, the exhaust valve 3 will open.

As described above, the exhaust braking force greatly depends on the set load F of the valve spring 40. When the thus the pressure P ₁ of the exhaust passage section 80 is too large, no longer exhaust valve 3 can no longer be opened and closed by the valve timing of normal, resulting bounce like so-called dance of the exhaust valve 3,
In the worst case, the engine will be damaged.

At this time, a maximum in-cylinder pressure of 43 (kg / cm ² ) is generated in No. 4 cylinder in the compression stroke. FIG. 9 shows a PV diagram when the exhaust brake is used alone.

FIG. 10 shows a case where the present engine brake device and the exhaust brake device 68 are simultaneously operated. At this time, even if the same exhaust shutter 69 is used, the pressure P _{1 in the} exhaust passage section 80 only rises to 3.9 (kg / cm ² ). The reason is that the exhaust gas flows backward into the cylinder at No. 2 cylinder in the intake stroke. This is because there is a cylinder in which the exhaust valve 3 is open regardless of the intake stroke, as the apparatus is a normally open type. At this time, the exhaust stroke No. 1 cyl
Although the exhaust braking force is slightly smaller than that of the above-mentioned case alone, the compression braking force is generated at the No. 4 cylinder in the compression stroke, so that a total braking force is obtained as compared with the case of the exhaust braking device alone. Naturally pressure P ₁
Therefore, there is no need to worry about the dance of the exhaust valve 3 or damage to the engine. Conversely, it is not necessary to use a strong valve spring 40.

At this time, a maximum in-cylinder pressure of 25 (kg / cm ² ) is generated in No. 4 cylinder in the compression stroke. FIG. 11 shows a PV diagram at the time of the combined operation. In this case, the braking force greatly depends on the normally-open lift amount of the exhaust valve 3 and the degree of throttle of the exhaust shutter 69.

For the reasons described above, the present apparatus uses only the conventional exhaust brake only in the entire rotation range (FIG. 7).
, A higher braking force can be obtained.

As described above, various other embodiments of the present invention can be considered.

[0075]

In summary, according to the present invention, the following excellent effects are exhibited.

(1) The size and cost of the brake unit can be reduced.

(2) High reliability and durability can be ensured.

(3) A high braking force can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view showing a mounting state of a brake unit.

FIG. 2 is an enlarged vertical sectional front view of a brake unit.

FIG. 3 is a vertical sectional front view of the solenoid valve unit.

FIG. 4 is a system diagram of an engine brake device and an exhaust brake device.

FIG. 5 is a perspective view showing an attached state of the engine brake device.

FIG. 6 is an intake / exhaust valve lift diagram.

FIG. 7 is a diagram showing brake characteristics of an engine brake device and an exhaust brake device.

FIG. 8 is a schematic diagram showing an engine state when the exhaust brake device operates alone.

FIG. 9 shows a PV diagram when the exhaust brake device operates alone.

FIG. 10 is a schematic diagram showing an engine state when the engine brake device and the exhaust brake device are operated in combination.

FIG. 11 shows a PV diagram when the engine brake device and the exhaust brake device are operated in combination.

[Description of Signs] 1 Brake unit 2 Solenoid valve unit 3 Exhaust valve 4 Actuator piston 5 Check ball 6 Switching plunger 7 Actuator body 8 Male screw 9 Unit body 11 Female screw hole 20 Piston spring seat 22 Top wall 33 Oil first passage 34 Oil second passage 35 Groove 37 Lock nut 47 Connecting unit body 49 Casing 50 Oil piping 67 Electronic control unit 68 Exhaust brake device 72 Manual switch 75 Cylinder head C Reference axis G Gap N Switching speed

Continued on front page F-term (reference) 3G016 AA06 AA12 AA19 BB17 BB22 CA04 CA11 CA12 CA14 CA21 CA24 CA27 CA29 CA33 CA36 CA41 CA48 CA52 DA13 DA18 DA22 DA23 DA24 FA12 FA26 GA00 GA01 GA05 GA06 3G065 AA01 AA04 AA09 CA00 KA05 EA05 3G092 AA13 DA14 DA15 DC13 DF04 DF09 DF10 DG02 DG05 DG09 EA09 EA11 EA12 EA28 EA29 FA13 FA34 FA48 FA49 FA50 HE01Z

Claims (11)

[Claims] 1. An actuator piston, a check ball, and a switching plunger are arranged along a predetermined reference axis and coaxially therewith, and these are collectively housed in an actuator body. An engine brake device comprising a coaxial male screw, and the actuator body is screwed into a fixed unit body to form a brake unit for each cylinder. 2. The engine brake device according to claim 1, wherein the reference shaft is located coaxially with an exhaust valve of the engine. 3. The actuator body according to claim 1, wherein a male screw of the actuator body is projected above the unit body, and a lock nut is fastened to the projected portion to fix a relative position between the actuator body and the unit body. 2
The described engine brake device. 4. The actuator body according to claim 1, further comprising a pair of stopper portions that abut on said actuator piston and regulate a movement amount thereof within a predetermined range.
An engine brake device according to any one of the above. 5. The engine brake device according to claim 1, wherein a working fluid passage is formed in a threaded portion between the actuator body and the unit body. 6. A connecting unit body in which the unit bodies for a plurality of cylinders are connected to each other to form a connecting unit body, and a fluid passage for supplying and discharging working fluid to and from a brake unit for each cylinder is provided inside the connecting unit body. Items 1 to 5
An engine brake device according to any one of the above. 7. The engine brake device according to claim 6, wherein the connecting unit body is supported on both sides of a cylinder head of the engine. 8. An electromagnetic valve for mounting and dismounting a frame-shaped casing mounted on an upper portion of a cylinder head of an engine and having the same shape as the casing. The engine brake device according to any one of claims 1 to 7, wherein the unit is mounted. 9. The electromagnetic valve unit is mounted at an intermediate position in the longitudinal direction of the casing, and the unit bodies of the front and rear cylinders are connected to each other at the position as a boundary to form a connection unit body, and the connection units before and after the connection unit body 9. The body and the solenoid valve unit are connected by piping.
The described engine brake device. 10. The engine brake device according to claim 1, which is used together with an exhaust brake device. 11. The control method for an engine brake device according to claim 10, wherein the operation and the non-operation of the engine brake device and the exhaust brake device are switched according to ON / OFF of a manual switch and the engine speed, When the manual switch is ON, the engine brake device is deactivated if the engine speed is less than a predetermined value, and the engine brake device is activated if the engine speed is equal to or more than the predetermined value. A method for controlling an engine brake device, wherein the exhaust brake device is activated at a rotation speed.