JPH09133031A - Compression opening type engine auxiliary brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent impurities or the like sticking to an exhaust system from reversely flowing in a combustion chamber and an intake system, while a large braking force can be obtained, relating to a compression opening type engine auxiliary brake device as an engine brake device. SOLUTION: A device is provided with an intake valve 27 capable of opening/ closing between a combustion chamber and an intake system of an engine 20, exhaust means 28 opening/closing between the combustion chamber and an exhaust system to make opening in an exhaust condition in an exhaust stroke, when the engine 20 is in ordinary operation, and a fuel supply means, and also exhaust by the exhaust means 28 in the exhaust stroke is stopped when the engine 20 is in prescribed operation. In this way, the device is constituted so as to provide an exhaust adjusting means 91 performing exhaust by the exhaust means 28 in the vicinity of a position of the top dead center of a piston, intake valve drive adjusting means 90 opening the intake valve 27 from in the vicinity of the top dead center position of the piston over to in the vicinity of a position of the bottom dead center of the piston and a fuel supply stop means stopping fuel supply of the fuel supply means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compression opening type engine auxiliary braking device that obtains a braking force by controlling engine valves such as intake valves and exhaust valves in an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, as one of engine brake devices, an exhaust brake device in which an on-off valve in an exhaust manifold is closed when an accelerator is turned off to increase exhaust pressure to increase engine braking capability has been widely used. Has been In addition to this, as an engine braking device, a compression opening type engine that increases the engine braking capacity by controlling the pressure state in the cylinder by opening and closing the exhaust valve at a timing different from normal exhaust timing when the accelerator is off An auxiliary braking device has been developed and put into practical use.

Such an exhaust brake device and a compression open type engine auxiliary brake device are mainly applied to heavy vehicles such as large trucks and buses, and particularly, an exhaust brake device and a compression open type engine auxiliary brake device. By using together, a strong engine brake is generated when the accelerator is off, and a large braking force is obtained while reducing the load on the service brake.

The operating principle of the above-mentioned compression opening type engine auxiliary braking device will be briefly described. When the braking device is operating, the intake valve and the exhaust valve are opened and closed as follows. That is, during the intake stroke, intake air is taken in by opening the intake valve as usual. Also, during the compression stroke, the intake valve and the exhaust valve are both closed as in normal operation to compress the intake air in the cylinder. As a result, the reaction of the compression force acts in a direction that prevents the piston from rising, and the engine braking force acts.

Next, immediately before shifting from the compression stroke to the expansion stroke, the exhaust valve is opened and the compressed intake air is discharged to the exhaust port via the exhaust valve. Therefore, the repulsive force of the intake air compressed in the compression stroke does not act on the piston, and no force acts in the direction of pushing down the piston.
Further, after discharging the compressed air, the exhaust valve is closed to make the inside of the cylinder airtight during the expansion stroke. As a result, a force that prevents the piston from descending is generated, and the engine braking force acts.

Next, when the piston reaches the vicinity of the bottom dead center and shifts to the exhaust stroke, the exhaust valve is opened as usual, and the inside of the cylinder is brought close to the atmospheric pressure. Thereafter, when the piston reaches the vicinity of the top dead center, the intake stroke is started again. Then, the braking force in such a compression stroke and an expansion stroke continuously acts on the piston, so that the engine braking ability is greatly increased. In other words, by causing the engine to perform a pump operation as a negative work, the kinetic energy of the vehicle is absorbed and converted into a braking force.

[0007] The energy thus converted into the braking force by the engine brake is hereinafter referred to as absorption horsepower.
Further, when the compression pressure release type engine auxiliary brake is operated, the fuel injection is stopped. The acupressure diagram shown in FIG. 10 shows the absorption horsepower when the compression release type engine auxiliary brake device and the exhaust brake device are simultaneously operated, and the area of the portion A is the compression release type. The absorption horsepower by the engine auxiliary braking device and the area of the portion B indicate the absorption horsepower by the exhaust braking device.

[0008]

SUMMARY OF THE INVENTION Incidentally, Japanese Patent Application Laid-Open No.
Japanese Patent No. 33684 discloses a technique for increasing the braking force of an exhaust brake device. However,
In the exhaust brake device, the absorption horsepower increases as the exhaust pressure increases, but if the exhaust pressure is raised too high, the exhaust manifold will become too high in pressure and the exhaust valves of other cylinders will open (hereinafter There is a case called a pressure regulation lift).

In order to prevent such a pressure-controlled lift, it is conceivable to increase the set load (spring constant) of the valve spring of the exhaust valve, but such an increase in the set load is excessive in the valve train. Will cause a heavy load. Therefore, the exhaust brake device has a problem that the exhaust pressure cannot be increased above a predetermined value.

In particular, when the exhaust brake device and the above-mentioned compression pressure release type engine auxiliary brake device are used together, there is a problem that the exhaust temperature rises and the valve seat wears. In order to solve such a problem, the absorption horsepower by the engine auxiliary braking device may be increased to generate sufficient engine braking force without the exhaust braking device.

Therefore, as disclosed in Japanese Patent Publication No. 63-30481, the engine is pumped twice at a rotation angle of 720 ° of the crankshaft of the engine (that is, two rotations of the crankshaft) to absorb the engine. Techniques for improving horsepower have been proposed. In this technique, during normal operation, the engine operates as a normal four-cycle engine, and during engine brake operation, it operates as follows.

That is, the crankshaft rotation angle is about 0 ° to
During 180 ° (corresponding to the intake stroke during normal operation), the intake valve is opened and air is taken in from the intake valve side. And
When the crankshaft rotation angle is between approximately 180 ° and 360 ° (corresponding to the compression stroke during normal operation), air is compressed, and when the piston is near the top dead center position, the exhaust valve is opened and compressed air is discharged to the exhaust side. Discharge.

The crankshaft rotation angle is about 360 °
During 540 ° (corresponding to the expansion stroke during normal operation), the piston descends while the exhaust valve is open, and air is taken in from the exhaust valve side. After this, the crankshaft rotation angle is about 540
Between ° and 720 ° (corresponding to the exhaust stroke during normal operation), the intake and exhaust valves are closed and the intake air is compressed, and when the piston is near the top dead center position, the intake valve opens and the intake valve side Compressed air is discharged. Then, this operation is repeated thereafter to pump the engine.

However, in such a conventional technique, the operation of sucking air from the intake valve side and discharging the compressed air to the exhaust valve side and the operation of sucking air from the exhaust valve side to discharge the compressed air to the intake valve side. The operation of exhausting is alternately repeated, and hot air and impurities (for example, NOx and particulates) after combustion of fuel adhering to the exhaust system flow back into the combustion chamber and the intake system from the exhaust system side. There is a problem that it will end up.

The present invention has been devised in view of the above problems, and makes it possible to obtain a large braking force only by the braking force of the engine auxiliary braking device without using the exhaust braking device, and to exhaust the exhaust gas. An object of the present invention is to provide a compression open type engine auxiliary braking device that prevents impurities and the like attached to the system from flowing back into the combustion chamber and the intake system.

[0016]

Therefore, the compression opening type engine auxiliary braking device of the present invention according to claim 1 opens and closes between the combustion chamber of the engine and the intake system, and intake air during normal operation of the engine. An intake valve that is driven to open in a stroke, an exhaust unit that opens and closes between the combustion chamber and an exhaust system, and opens to an exhaust state in an exhaust stroke during normal operation of the engine, and fuel to the combustion chamber. An exhaust gas adjusting means for supplying the fuel, and an exhaust gas adjusting means for stopping the exhaust by the exhaust means in the exhaust stroke and performing the exhaust by the exhaust means near the top dead center position of the piston during a predetermined operation of the engine. An intake valve drive adjusting means for opening the intake valve from near the top dead center position to near the bottom dead center position of the piston; and a fuel supply stopping means for stopping the fuel supply of the fuel supply means. It is characterized in that it comprises.

According to a second aspect of the present invention, in addition to the structure of the first aspect, the exhaust means opens the valve in an exhaust stroke during normal operation of the engine. An exhaust valve that is driven, wherein the exhaust adjusting means stops exhaust through the exhaust valve in an exhaust stroke of the engine during a predetermined operation of the engine, and the exhaust valve near the top dead center position of the piston. Is configured to be driven to open the valve.

According to a third aspect of the present invention, in addition to the structure of the first aspect, the exhaust means opens the valve in the exhaust stroke during normal operation of the engine. The engine includes a driven exhaust valve and a third valve that can separate communication between the combustion chamber and the exhaust system separately from the exhaust valve, and the exhaust adjusting means can operate the engine during a predetermined operation of the engine. In this exhaust stroke, the exhaust through the exhaust valve is stopped, and the third valve is driven to open in the vicinity of the top dead center position of the piston.

According to a fourth aspect of the present invention, in addition to the structure according to any one of the first to third aspects, the intake valve drive adjusting means includes:
The intake valve is opened in the intake stroke by an intake cam provided on a cam shaft that rotates in conjunction with the crankshaft of the engine, and the intake valve is forcibly forced in the expansion stroke regardless of the movement of the intake cam. Is characterized by opening the valve.

According to a fifth aspect of the present invention, in the compression-opening type engine auxiliary braking device according to the present invention, the exhaust means is provided on the camshaft in addition to the structure according to any one of the second to fourth aspects. It is characterized in that it is configured as an exhaust valve that is driven to open in the exhaust stroke during normal operation of the engine by the exhaust cam. In addition, claim 6
In the compression opening type engine auxiliary braking device of the present invention described above, in addition to the configuration of claim 4 or 5, the intake valve drive adjusting means transmits the valve opening drive force of the intake cam to the intake valve. An intake rocker arm, an intake rocker shaft that rotates integrally with the intake rocker arm, and a variable intake cam that is disposed on the cam shaft and is formed in a phase that can drive the intake valve to open during the expansion stroke of the engine. A variable intake rocker arm that is loosely fitted to the intake rocker shaft and has an end in constant contact with the variable intake cam; and a rocker arm engagement mechanism that engages the intake rocker shaft and the variable intake rocker arm. Is characterized by.

According to a seventh aspect of the present invention, there is provided the compression assist type engine auxiliary braking device according to the second aspect of the present invention, wherein the exhaust adjusting means includes the exhaust cam. An exhaust rocker arm that transmits the valve opening driving force of the exhaust valve to the exhaust valve, an exhaust rocker shaft that rotates integrally with the exhaust rocker arm, the exhaust valve that is disposed on the cam shaft, and the exhaust valve that is used in the compression stroke and the exhaust stroke. A variable exhaust cam arranged in a phase capable of opening and driving in the vicinity of the top dead center position, a variable exhaust rocker arm loosely fitted to the exhaust rocker shaft and having an end in constant contact with the variable exhaust cam, and the exhaust gas. It is characterized by having a rocker arm engaging mechanism for engaging the rocker shaft and the variable exhaust rocker arm.

According to an eighth aspect of the present invention, there is provided the compression opening type engine auxiliary braking device according to the second aspect, wherein the exhaust adjusting means opens the exhaust cam. An exhaust rocker arm that transmits a valve driving force to the exhaust means, an exhaust rocker shaft that rotates integrally with the exhaust rocker arm, and the exhaust means that is disposed on the cam shaft and is located above the piston in the compression stroke and the exhaust stroke. A variable exhaust cam disposed in a phase in which it is driven to open in the vicinity of the dead center position; a push-down mechanism provided above the exhaust means to push down the exhaust valve; and a piston member that reciprocates by the variable exhaust cam. It is characterized in that it is provided with a fluid circuit which connects and connects the piston member and the pushing-down mechanism.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to the drawings. FIGS. 1 to 6 are views for explaining a compression opening type engine auxiliary braking device as a first embodiment of the present invention. FIG. 1 shows a valve mechanism 2 of a 4-cycle diesel engine (hereinafter, simply referred to as engine) 20.
FIG. 3 is a schematic top view showing No. 3, showing one arbitrary cylinder of a diesel engine. As shown in FIG. 1, the engine 20 includes an OHC type valve operating mechanism 23.
It has a four-valve engine with two intake valves and two exhaust valves. Although not shown, the engine 20 is provided with a known fuel supply device.

The valve mechanism 23 of the engine 20 is provided with a cam shaft 24 which is driven by a rotational driving force from a crank shaft (not shown). The cam shaft 24 is suitable for normal operation of the engine 20. An intake cam 25 and an exhaust cam 26 formed in a different cam profile are provided. A rocker shaft 21 is provided in the valve mechanism 23 of the engine 20. The rocker shaft 21 is divided for each cylinder, and is further divided into an intake rocker shaft 21A and an exhaust rocker shaft 21B in each cylinder. Further, the intake rocker shaft 21A and the exhaust rocker shaft 21B are coaxially arranged, and as shown in FIG. 1, the rocker shafts 21A and 21B are rotatably supported by bearing members 60, 61 and 62. Has been done.

An intake valve 27 and an exhaust valve (exhaust means) 28 are arranged above the cylinder. An intake valve bridge 34 as shown in FIG. 2 is arranged above the intake valve 27.
4, the two intake valves 27 are driven to open at the same time. Further, above the exhaust valve 28, the exhaust valve bridge 35 as well as the intake valve bridge 34 is provided.
Is also provided.

These valve bridges 34 and 35 are designed to be driven in the vertical direction according to the rocking of rocker arms 29 and 30 as shown in FIG. 1, whereby the intake and exhaust valves 27 and 28 are opened and closed. It is designed to be driven.
Here, the intake rocker arm 29 is configured as a rocker shaft-integrated rocker arm that operates integrally with the intake rocker shaft 21A described above, and the rocker shaft 21A also rotates as the intake rocker arm 29 swings. .

Further, at the end of the intake rocker arm 29 on the camshaft 24 side, the roller 6 which is constantly in contact with the intake cam 25 is provided.
3 is provided to smoothly transmit the operation of the intake cam 25 to the intake rocker arm 29. Therefore, during normal operation of the engine, the rocker arm 29 is driven at a timing corresponding to the cam profile of the intake cam 25.
Oscillates to open and close the intake valve 27.

The valve mechanism 23 has a piston 8
3 (see FIG. 4) intake valve drive adjusting means 90 for opening the intake valve 27 from near the top dead center position to near the bottom dead center position.
Is provided. Further, the intake valve drive adjusting means 90
Is mainly composed of a cam (variable intake cam) 75 for engine auxiliary braking, a variable intake rocker arm 70, and a rocker arm engagement mechanism 71 for disconnecting or connecting the variable intake rocker arm 70 to the rocker arm 29.

As shown in FIG. 1, the variable intake rocker arm 70 is provided adjacent to the intake rocker arm 29. The variable intake rocker arm 70 and the intake rocker shaft 21A are rotatably provided, and the intake rocker shaft 21A has a mode in which the variable intake rocker arm 70 is separated from the intake rocker shaft 21A and does not work in association with the intake rocker arm 29 (non-coupling mode). ), And a variable intake rocker arm 70 integrally rotates with the intake rocker shaft 21A so that the variable intake rocker arm 70 and the intake rocker arm 29 operate in a linked mode (coupling mode). It is provided.

As shown in FIG. 2, the hydraulic piston mechanism 71 has a hole 72 formed in the diametrical direction of the rocker shaft 21A and a pin member 73 capable of moving forward and backward in the hole 72.
Is provided. A return spring (not shown) is arranged on the upper end side of the pin member 73, and the return spring action urges the pin member 73 downward in the drawing.

Further, the hole 7 into which the upper end portion of the pin member 73 can enter at a required position of the variable intake rocker arm 70.
4 are formed. Furthermore, this engine 20
A hydraulic pressure supply system (not shown) that supplies hydraulic oil of a specified pressure
Is provided, and the working oil is supplied to the space formed by the upper end side of the pin member 73 and the hole 72 through this hydraulic pressure supply system.

When hydraulic oil is supplied to this space, the pin member 73 is resisted against the biasing force of the return spring.
Moves upwards. In this case, the pin member 73 engages with the hole 74 formed in the rocker shaft 21A, the variable intake rocker arm 70 and the intake rocker shaft 21A are connected, and the rocker arm 70 and the intake rocker arm 2 are connected.
9 becomes a linked mode in which 9 and 1 work together.

When the supply of hydraulic oil is cut off, the pin member 73 moves downward due to the urging force of the return spring, and the pin member 73 is disengaged from the hole 74. In this case, the variable intake rocker arm 70 has the rocker shaft 21
It becomes the non-coordination mode separated from A. Further, the valve mechanism 23 of the engine 20 is provided with a cam (variable intake cam) 75 for engine auxiliary braking adjacent to the intake cam 25. The variable intake rocker arm 70 described above is used for this engine auxiliary brake. It is designed to be driven by the cam 75.

A cam 75 for this engine auxiliary brake
Has the same or substantially the same cam profile as the intake cam 25, and has a phase of 180 ° with respect to the intake cam 25.
They are arranged differently. In addition, the intake rocker arm 2 is provided at the contact portion between the variable intake rocker arm 70 and the cam 75.
As with 9, the roller 76 is provided. Therefore, the variable intake rocker arm 70 is
When the variable intake rocker arm 70 enters the linkage mode in which the variable intake rocker arm 70 operates integrally with the intake rocker arm 29, the intake valve is operated at every rotation angle of 360 ° of the crankshaft of the engine 20. The valve 27 is driven to open.

That is, regardless of the intake stroke or the exhaust stroke, the intake valve 27 opens from the vicinity of the top dead center to the vicinity of the bottom dead center of the piston 83, and the intake valve 27 operates in two cycles. Further, during normal operation, that is, in the non-coupling mode in which the variable intake rocker arm 70 is separated from the rocker shaft 21A, the opening / closing operation of the intake valve 27 is not affected by the operation of the variable intake rocker arm 70, and the crank is operated as usual. The intake valve 27 is driven to open every rotation angle of the shaft of 720 ° (two rotations of the crankshaft).

Next, the valve operating mechanism 23 on the exhaust valve 28 side will be described. In this valve operating system 23, the operation of the exhaust valve 28 in the exhaust stroke is stopped so that the exhaust gas near the top dead center of the piston 83 is exhausted. An exhaust adjusting means 91 for operating the valve 28 is provided, and the exhaust adjusting means 91 mainly includes an exhaust rocker arm 30, a variable exhaust cam 31, and a fluid circuit 80.

Further, the exhaust rocker arm 30 is similar to the intake rocker arm 29 described above in that the exhaust rocker shaft 21
It is configured as a rocker shaft-integrated rocker arm that operates integrally with B. The exhaust rocker arm 30 is not in direct contact with the exhaust cam 26, and the exhaust rocker arm 30 is swung by the exhaust roller arm 65 shown in FIG.

As shown in FIG. 1, the exhaust roller arm 65 is provided adjacent to the exhaust rocker arm 30 and is pivotally supported by the exhaust rocker shaft 21B. The exhaust roller arm 65 and the exhaust rocker shaft 21B are rotatably provided. The exhaust rocker shaft 21B has a mode in which the exhaust roller arm 65 is separated from the exhaust rocker shaft 21B and does not operate in cooperation with the exhaust rocker arm 30. A hydraulic piston mechanism (rocker arm) capable of switching between (non-coupling mode) and a mode (coupling mode) in which the exhaust roller arm 65 rotates integrally with the exhaust rocker shaft 21B and the exhaust roller arm 65 and the exhaust rocker arm 30 cooperate. An engaging mechanism) 66 is provided.

The hydraulic piston mechanism 66 has a structure substantially similar to that of the hydraulic piston mechanism 71 described above.
As shown in FIG. 3, the rocker shaft 21 </ b> B is provided with a hole 67 formed in the diameter direction and a pin member 68 capable of moving forward and backward in the hole 67. A return spring (not shown) is disposed on the lower end side of the pin member 68, and the return spring urges the pin member 68 upward.

Further, at a required position of the roller arm 65, a hole 69 into which the upper end of the pin member 68 can be inserted is formed. Further, the working oil is supplied to the space formed by the upper end side of the pin member 68 and the hole 67, also via a hydraulic pressure supply system (not shown). When the hydraulic oil is supplied to this space, the pin member 68 moves downward against the biasing force of the return spring, and the state shown in FIG. 3 is obtained.

In this case, the pin member 68 is separated from the hole 67 formed in the rocker shaft 21B, and the roller arm 65 is separated from the rocker shaft 21B to be in the non-coupling mode. On the other hand, when the supply of the hydraulic oil to the rocker shaft 21B is stopped, the pin member 68 moves upward due to the urging force of the return spring described above, and the pin member 6
8 engages the hole 67. Therefore, the exhaust roller arm 65 and the exhaust rocker shaft 21B are in a connected state, and the exhaust roller arm 65 and the exhaust rocker arm 30 are in a linked mode in which they operate integrally.

A roller 64 is also provided at the end of the exhaust roller arm 65 on the camshaft 24 side, like the variable intake rocker arm 70, so that the operation of the exhaust cam 26 can be smoothly transmitted to the exhaust roller arm 65. It has become. Further, the control of the supply state of the hydraulic oil in the rocker shafts 21A, 21B, that is, the control of the hydraulic pressure supply system is
Engine control unit (ECU) 8 shown in FIG.
1 is executed.

By the way, the exhaust valve 28 of the engine 20.
As shown in FIGS. 1 and 4, a fluid circuit 80 for an engine auxiliary braking mechanism is provided for each cylinder above the side valve mechanism 23. The fluid circuit 80 is provided with an oil passage forming body 39 as an essential part thereof, and the oil passage forming body 39 is formed with an operating oil passage 41 and a distribution passage 42.

A master piston 46, which is a piston member driven by a variable exhaust cam 31 described later, is inserted into one end of the hydraulic oil passage 41.
A return spring 48 for urging the master piston 46 downward is provided above. A slave piston 40 as a push-down mechanism is provided in the middle of the hydraulic oil passage 41.
0 is slidably fitted in a hole 53 formed in the oil passage forming body 39.

Further, below the slave piston 40,
A return spring 54 that biases the slave piston 40 upward is provided, and a stopper 55 that abuts the slave piston 40 and restricts upward movement is provided above the hole 53. The other end of the hydraulic oil passage 41 is connected to the distribution passage 42 via the control valve 44. Further, a sonolaid valve 45 is provided at the end of the distribution path 42, and
5 is switched to supply the working oil as a non-compressible fluid pressurized by the pump 82 to the working oil passage 41 and the distribution passage 42, or drain the working oil in the working oil passage 41 and the distribution passage 42. It is supposed to do. The solenoid valve 45 is an engine control unit (EC
U) 81.

The control valve 44 is slidably fitted in a space 441 formed in the vertical direction and is urged downward by a return spring 442. Further, the control valve 44 is configured as a one-way valve, and when the solenoid valve 45 is switched on and hydraulic oil is supplied from the pump 82 to the distribution passage 42,
The control valve 44 rises against the return spring 442 and closes the hydraulic oil passage 41.

In this case, when the pressure of the hydraulic oil in the hydraulic oil passage 41 becomes lower than that of the high pressure oil in the distribution passage 42, the high pressure oil is supplied into the hydraulic oil passage 41 via the control valve 44. On the other hand, when the solenoid valve 45 is switched off and the distribution line 42 becomes low in pressure, the control valve 44 descends and the hydraulic oil in the hydraulic oil line 41 is released from the opening 4.
It is designed to be drained via 43.

Further, the slave piston 40 is formed so that its lower end can come into contact with the exhaust rocker arm 30, and when the slave piston 40 receives a pressing force of hydraulic oil, it pushes the exhaust rocker arm 30 and a pair of the slave piston 40 through the exhaust valve bridge 35. The exhaust valve 28 is driven to open. Now,
The variable exhaust cam 31 will now be described. The variable exhaust cam 31 has a camshaft 24, as shown in FIG.
The cam is a cam that is rotated once by two rotations of the crankshaft, like the intake and exhaust cams 25 and 26.

The variable exhaust cam 31 is formed so as to drive the exhaust valve 28 to open in two cycles when the solenoid valve 45 is turned on. Therefore, the cam profile of the variable exhaust cam 31 is As shown in FIG. 4, cam crests are provided at two locations. In addition, each mountain is 1
It has a phase difference of 80 °, and the cam profiles of the cam peaks are the same.

The variable exhaust cam 31 has a piston 83.
Is arranged at such a timing that the master piston 46 is moved to the maximum stroke when is at the top dead center position.
In addition, in the above-mentioned engine control unit 81,
Various sensors such as an accelerator switch (not shown) are connected, and driving operation information of the driver is input.

Since the compression opening type engine auxiliary braking device according to the first embodiment of the present invention is constructed as described above, during normal operation of the engine 20, the valve timing as shown in FIG. When the intake / exhaust valves 27, 28 are driven by and the engine auxiliary braking device is operated, the intake / exhaust valves 27, 28 are driven with the valve timing characteristics as shown in FIG. 5B, for example.

First, the normal operation of the engine 20 will be described. In this case, based on the control signal from the ECU 81, the rocker shafts 21A, 2A from the hydraulic pressure supply system are controlled.
The hydraulic pressure supply to 1B is stopped. Further, the solenoid valve 45 of the fluid circuit 80 is controlled to be off, and the supply of the high pressure hydraulic oil into the hydraulic oil passage 41 of the oil passage former 39 is also stopped.

In this case, the hydraulic piston mechanism 71 on the intake rocker arm 29 side is controlled to the non-coupling mode. That is, by cutting off the supply of hydraulic oil into the intake rocker shaft 21A, the pin member 73 shown in FIG. 2 is urged downward by the urging force of the return spring (not shown), and the pin member 73 is disengaged from the hole 74. . As a result, the intake rocker shaft 21A and the variable intake rocker arm 70 are separated from each other, so that the intake valve 27 is opened and closed according to the cam profile of the intake cam 25, and the valve opening operation is performed at a timing suitable for normal operation.

Further, the hydraulic piston mechanism 66 on the exhaust rocker arm 30 side is controlled in the linkage mode. That is, when the supply of hydraulic oil to the exhaust rocker shaft 21B is cut off,
The pin member 68 shown in FIG. 3 is biased upward by the biasing force of a return spring (not shown), and the pin member 68 engages with the hole 69. As a result, the rocker shaft 21B
The exhaust roller arm 65 is connected to the exhaust roller arm 65, and the exhaust rocker arm 30 integrated with the rocker shaft swings in accordance with the cam profile of the exhaust cam 26.

Further, when the solenoid valve 45 of the fluid circuit 80 is controlled to be turned off, the control valve 44 descends. Therefore, even if the master piston 46 is driven, the inside of the hydraulic oil passage 41 does not become a high pressure state, and the slave Piston 40
Does not work either. Therefore, the exhaust rocker arm 30
The exhaust valve 26 swings only in accordance with the cam profile of the exhaust cam 26, and the exhaust valve 28 is opened and closed at a timing suitable for normal operation.

The operation of the intake / exhaust valves 27 and 28 during the normal operation will be described in the same manner as a normal four-cycle engine. That is, FIG.
As shown in, the intake valve 27 begins to open immediately before the piston 83 reaches the top dead center (crankshaft rotation angle = 0 °), and the bottom dead center of the piston 83 (crankshaft rotation angle = 18).
0 °) is closed near the position (suction stroke). After that, the piston 83 rises to compress the air in the cylinder (compression stroke), and injects fuel before the top dead center (crankshaft rotation angle = 360 °) position. Then, this fuel is ignited and the piston 83 is pushed down (expansion stroke or combustion stroke).

Further, when the piston 83 is near the bottom dead center (crankshaft rotation angle = 540 °) position, the exhaust valve 28
Starts to open, and exhaust gas is discharged (exhaust stroke). After this, the piston 83 moves to the top dead center (crankshaft rotation angle = 720
In the vicinity of the (°) position, the exhaust valve 28 is closed and the intake valve 27 begins to open. Thus, during normal operation, the crankshaft operates as a four-cycle engine in which the rotation angle of the crankshaft is 720 °, that is, when the crankshaft rotates twice, the engine 20 completes a series of operations.

On the other hand, when the ECU 81 determines based on the information from the various sensors that the engine auxiliary brake is in the required operating state, the fuel supply by the fuel supply device (not shown) is stopped, and the hydraulic supply system operates the rocker shafts. Supply hydraulic oil into 21A and 21B. Further, the solenoid valve 45 of the fluid circuit 80 is controlled to be turned on, and the high pressure hydraulic oil is supplied into the hydraulic oil passage 41 of the oil passage forming body 39.

In this case, the hydraulic piston mechanism 71 on the intake rocker arm 29 side is controlled to the linkage mode. That is, by supplying the hydraulic oil into the intake rocker shaft 21A, the pin member 73 is driven upward against the urging force of the return spring, and the pin member 73 is opened in the hole portion 74.
Engages. As a result, the intake rocker shaft 21A and the variable intake rocker arm 70 are connected, and the intake valve 27
Is the cam 75 for the engine auxiliary brake and the intake cam 25.
It will be opened and closed according to the cam profile of

Here, as described above, the engine auxiliary brake cam 75 is formed with the same or substantially the same cam profile as the intake cam 25, and has a phase on the camshaft 24 with respect to the intake cam 25. Since the intake valves 27 are arranged 180 degrees apart, the intake valve 27 is driven to open each time the piston is near the top dead center position. Also,
The hydraulic piston mechanism 66 on the exhaust rocker arm 30 side is controlled to the non-coupling mode. In other words, exhaust rocker shaft 2
When hydraulic oil is supplied into 1B, the pin member 68 is urged downward against the urging force of the return spring, and the pin member 68 separates from the hole 69. As a result, the rocker shaft 21B and the exhaust roller arm 65 are separated.

In such a non-coordination mode,
Even if the exhaust roller arm 65 is driven, the exhaust rocker arm 30 does not operate. When the solenoid valve 45 of the fluid circuit 80 is controlled to be turned on, the control valve 44 moves up and the hydraulic oil passage 41 in the oil passage forming body 39 is filled with high-pressure hydraulic oil.

Therefore, when the master piston 46 is driven, the slave piston 40 is driven via this hydraulic oil. When the slave piston 40 is driven downward against the return spring 54,
The exhaust roller arm 65 is pressed to drive the exhaust valve 28 to open. The master piston 46 is driven by the variable exhaust cam 31, but as described above, the variable exhaust cam 31 has a timing at which the master piston 46 makes a maximum stroke when the piston 83 is at the top dead center position. Therefore, when the piston 83 approaches the top dead center position, the exhaust valve 28 is driven to open every time. That is, the exhaust valve 28 also operates in two cycles such that the exhaust valve 28 is driven to open every crankshaft rotation.

Generally, when operating the piston member 40 and the like by using a working fluid as a medium, the master piston 46
Although the stroke amount of the slave piston 40 becomes smaller than the stroke amount of, the valve lift amount of the exhaust valve 28 at the time of operating the engine auxiliary brake may be relatively small, and in consideration of the clearance with the piston 83. The lift amount of the exhaust valve 28 at this time is set to be small.

Therefore, when such an engine auxiliary brake is operated, the intake / exhaust valves 27 and 28 are set as shown in FIG.
As shown in, the valve operates in two cycles such that the valve opening operation is performed once for each rotation of the crankshaft. That is, the intake valve 2
7, the piston 83 has a top dead center (crankshaft rotation angle = 0.
The opening of the piston 83 starts immediately before it reaches (°), and the piston 83 is closed near the bottom dead center (crankshaft rotation angle = 180 °) (suction stroke). After this, the piston 83 moves up to compress the air in the cylinder (compression stroke), and when it is near the top dead center (crankshaft rotation angle = 360 °) position, the exhaust valve 28
Opens to discharge the compressed air to the exhaust system, and the intake valve 27 opens again to suck the air. In this case,
Fuel injection is stopped as described above.

By thus operating the engine 20 as a pump and performing the negative work of compressing air, the running energy of the vehicle is absorbed and converted into a braking force. The energy converted into the braking force by the engine brake in this way is hereinafter referred to as absorption horsepower. Particularly, in the compression open type engine auxiliary braking device of the present invention, such an operation is performed by the rotation angle 36 of the crankshaft.
By repeating the operation every 0 ° (that is, every time the crankshaft makes one revolution), the engine auxiliary brake operates in two cycles, and a larger absorption horsepower can be obtained.

FIG. 6 shows a schematic acupressure diagram when the compression opening type engine auxiliary braking device is operated. In this figure, the area surrounded by the closed curve is the absorption horsepower of the engine 20, and the absorption horsepower obtained by this intake stroke and compression stroke (this compression stroke includes the exhaust stroke) is obtained by one crankshaft revolution. Be done.

As described above, according to the compression opening type engine auxiliary brake device of the present invention as described above, the absorption horsepower larger than that of the normal engine auxiliary brake can be obtained by operating the engine auxiliary brake in two cycles. It is possible to obtain a strong braking force. Further, in this compression opening type engine auxiliary braking device, since the absorption horsepower can be increased, it is not necessary to provide a conventional exhaust braking device, and thus it is possible to suppress an excessive increase in exhaust pressure.

Therefore, it is possible to avoid a phenomenon in which the pressure inside the exhaust manifold becomes too high due to the operation of the exhaust brake device and the exhaust valves of the other cylinders open (pressure adjustment lift). Further, conventionally, when the exhaust brake device and the compression opening type engine auxiliary brake device are used in combination, the set load (spring constant) of the valve spring of the exhaust valve 28 is set in order to prevent the pressure regulating lift as described above. Although it was necessary to set a large value, according to the compression opening type engine auxiliary brake device of the present invention, the exhaust brake device can be eliminated, and thus such an increase in the set load of the valve spring can be avoided. ,
There is an advantage that the load on the valve train due to the strong set load of the valve spring can be reduced.

Further, by eliminating the exhaust brake device, it is possible to suppress an excessive rise in the exhaust temperature and avoid wear of the scavenging air of the valve seat, especially the valve seat on the exhaust valve side. Further, by using the engine with the supercharger and the main compression pressure release type engine auxiliary braking device together, it is possible to expect an increase in intake pressure by the supercharger, and it is possible to further increase the absorption horsepower by the engine 20. There is also an advantage.

Further, since the intake air is sucked in through the intake valve 27 and discharged through the exhaust valve 28 into the exhaust system during the operation of the present apparatus, the prior art (for example, Japanese Patent Publication No. 63-304).
81), the hot air from the exhaust system side and impurities (for example, NOx and particulates) after combustion of the fuel adhering to the exhaust system are again generated in the combustion chamber. It also has the advantage of preventing backflow to the.

Next, a compression open type engine auxiliary braking device according to a second embodiment of the present invention will be described.
The second embodiment is different from the compression opening type engine auxiliary braking device of the first embodiment in that the exhaust means is mainly different, and other than that, the second embodiment is configured similarly to the first embodiment. There is. As shown in FIG. 7, the engine 20 including the compression opening type engine auxiliary brake device according to the second embodiment includes an OHC type valve operating mechanism 23.
One intake valve 27 and one exhaust valve 28 are provided. Further, an exhaust valve 28 that operates during normal operation of the engine 20 and a third valve 28a that is driven to open in the engine auxiliary brake device are provided as exhaust means.

The third valve 28a is arranged adjacent to the intake valve 27 and the exhaust valve 28, and the fluid circuit 80 is provided above the third valve 28a. In addition, the intake valve 2
7. The intake valve 29 and the exhaust valve 28 are driven to be opened by an intake rocker arm 29 and an exhaust rocker arm 30, respectively, and the third valve 28a is driven to be opened by a slave piston 40 provided in a fluid circuit 80. It has become. The valve operating mechanism 23 is provided with a variable intake rocker arm 70 and an exhaust roller arm 65 adjacent to the rocker arms 29 and 30.

The variable intake rocker arm 70 is driven by the engine auxiliary brake cam 75, and the engine auxiliary brake cam 75 is connected to the engine 20.
Is formed in a cam profile similar to that of the intake cam 25 during normal operation of the
At a phase difference of 180 °. On the other hand, the exhaust roller arm 65 is driven by the exhaust cam 26 for normal operation of the engine 20.

As shown in FIG. 7, a hydraulic piston mechanism 71 is provided on the intake valve 27 side to separate the variable intake rocker arm 70 from the intake rocker shaft 21A so that the rocker arm 70 is linked to the intake rocker arm 29. A mode (non-coupling mode) that does not operate and a mode (coordination mode) in which the variable intake rocker arm 70 rotates integrally with the intake rocker shaft 21A and the rocker arm 70 and the intake rocker arm 29 operate in coordination are switched.

Further, a hydraulic piston mechanism 66 is provided on the exhaust valve 28 side, and the exhaust roller arm 65 and the exhaust rocker shaft 21B are separated from each other so that the exhaust roller arm 65 does not operate in cooperation with the exhaust rocker arm 30 ( The non-coupling mode) and the mode (coordination mode) in which the exhaust roller arm 65 rotates integrally with the exhaust rocker shaft 21B and the exhaust roller arm 65 and the exhaust rocker arm 30 operate in cooperation with each other are switched.

The respective hydraulic piston mechanisms 66, 71 are constructed in the same manner as in the first embodiment, and the switching control is performed by the ECU 81. That is, when the hydraulic oil is supplied into the rocker shafts 21A and 21B, the pin member 73 is provided on the rocker shaft 21A side.
Engages with a hole 74 (see FIG. 2) formed in the rocker shaft 21A to form an intake rocker arm 29 and a variable intake rocker arm 70 integrally formed with the rocker shaft 21A.
This is a linked mode in which and work together.

When the hydraulic oil is supplied into the rocker shaft 21B, the pin member 68 separates from the hole 67 (see FIG. 3) formed in the rocker shaft 21B, and the roller arm 65 separates from the rocker shaft 21B. It becomes the non-coordination mode. On the other hand, when the supply of hydraulic oil is stopped, in the rocker shaft 21A, the pin member 73 separates from the hole 74, and the variable intake rocker arm 70 enters a non-coupling mode in which the variable intake rocker arm 70 is separated from the rocker shaft 21A.

Further, in the rocker shaft 21B, the pin member 68 is engaged with the hole portion 67, and the exhaust roller arm 65 is provided.
The exhaust rocker shaft 21B is connected to the exhaust rocker shaft 21B, and the exhaust roller arm 65 and the exhaust rocker arm 30 are integrally operated. Next, the fluid circuit 80 will be described. The fluid circuit 80 is also configured similarly to that of the above-described first embodiment.

That is, an oil passage forming body 39 is formed in the fluid circuit 80, and in the oil passage forming body 39, the solenoid valve 4 controlled based on a control signal from the ECU 81.
5 (see FIG. 4) are provided. The high-pressure hydraulic oil is supplied into the oil passage forming body 39 or the supply of the hydraulic oil is stopped in accordance with the on / off control positions of the solenoid valve 45.

A master piston 46 is arranged at one end of the oil passage forming body 39, and the master piston 46 is driven by the variable exhaust cam 31 having two cam ridges. . Further, the cam peaks of the variable exhaust cam 31 have a phase difference of 180 °, and the cam profiles of the cam peaks are the same. Also,
Inside the oil passage formation body 39, a slave piston 40 which is in contact with the third valve 28a and can drive the third valve 28a to open is provided above the third valve 28a.

Therefore, when the solenoid valve 45 is controlled to the ON position and the high pressure hydraulic oil is supplied to the oil passage forming body 39, the driving state of the master piston 46 is transmitted to the slave piston 40 using the high pressure hydraulic oil as a medium. become.
That is, when the master piston 46 is driven by the variable exhaust cam 31 and moves upward, pressure acts on the high-pressure hydraulic oil to push down the slave piston 40.

As a result, the third valve 28a is driven to open, but as described above, the variable exhaust cam 31 is used.
Since the cam crests are formed at two locations with a phase difference of 180 °, the third valve 28a operates in two cycles such that the third valve 28a opens once for one rotation of the crankshaft. On the other hand, when the solenoid valve 45 is switched off, the hydraulic oil in the oil passage forming body 39 is drained and the third
The valve opening drive of the valve 28a is stopped.

Since the compression opening type engine auxiliary braking device according to the second embodiment of the present invention is constructed as described above, the intake valve 27, the exhaust valve 28 and the third valve 28a.
Will operate at the valve timings shown in FIGS. 8 (a) and 8 (b). First, the normal operation of the engine 20 will be described. At this time, the hydraulic pressure supply to the rocker shafts 21A and 21B is stopped based on the control signal from the ECU 81.

Further, the solenoid valve 4 of the fluid circuit 80
No. 5 is controlled to be off based on a control signal from the ECU 81, and the supply of high-pressure hydraulic oil into the oil passage formation body 39 is also stopped. In this case, the hydraulic piston mechanism 71 on the intake rocker arm 29 side is in the non-coupling mode,
The intake valve 27 is driven to open and close according to the cam profile of the intake cam 25, and performs the valve opening operation at a timing suitable for normal operation.

Further, the hydraulic piston mechanism 66 on the exhaust rocker arm 30 side is controlled in the linkage mode, and the rocker shaft 21B and the exhaust roller arm 65 are connected. Therefore, the rocker shaft integrated exhaust rocker arm 30
Oscillates according to the cam profile of the exhaust cam 26, and the exhaust valve 28 also performs a valve opening operation at a timing suitable for normal operation.

On the other hand, the solenoid valve 4 of the fluid circuit 80
By controlling 5 to be off, the hydraulic oil of the oil passage forming body 39 is drained. Therefore, the slave piston 40
Is stopped and the valve opening operation of the third valve 28a is stopped. Therefore, during such a normal operation, the intake / exhaust valves 27 and 28 are operated at the valve timing as shown in FIG. The operation of the intake / exhaust valves 27, 28 at this time is the same as that of a normal four-cycle engine, and has been described in detail in the first embodiment, so the description thereof is omitted here. The valve timing characteristic shown in FIG. 8 (a) is the same as the valve timing characteristic shown in FIG. 5 (a).

Next, the operation of the engine auxiliary braking device will be described. First, when the ECU 81 determines based on information from various sensors that the engine auxiliary brake is in the required operating state, the fuel supply by the fuel supply device (not shown) is stopped and the rocker shafts 2
The hydraulic oil is supplied into 1A and 21B. Further, the solenoid valve 45 of the fluid circuit 80 is controlled to be turned on, and the high pressure hydraulic oil is supplied into the oil passage forming body 39.

In this case, the hydraulic piston mechanism 71 on the intake rocker arm 29 side is controlled to the linkage mode, and the intake rocker shaft 21A and the variable intake rocker arm 70 are connected. Therefore, the intake valve 27 is driven to be opened and closed according to the cam profiles of the engine auxiliary brake cam 75 and the intake cam 25, and the intake valve 27 is opened each time the piston 83 is near the top dead center position. Will be driven.

That is, the intake valve 27 operates in two cycles such that the intake valve 27 is driven to open every crankshaft rotation. Further, the hydraulic piston mechanism 66 on the exhaust rocker arm 30 side is controlled to the non-coupling mode. That is, when the hydraulic oil is supplied into the exhaust rocker shaft 21B, the rocker shaft 21B and the exhaust roller arm 65 are separated.

Then, in such a non-coordination mode,
Even if the exhaust roller arm 65 is driven, the exhaust rocker arm 30 does not operate, and the operation of the exhaust valve 28 is stopped.
On the other hand, in the fluid circuit 80, the solenoid valve 45 is controlled to be turned on based on the control signal from the ECU 81, whereby the oil passage forming body 39 is filled with high-pressure hydraulic oil.

Therefore, when the master piston 46 is driven by the variable exhaust cam 31, the slave piston 40 is driven via this hydraulic oil to drive the third valve 28a to open. Further, as in the first embodiment, the variable exhaust cam 31 is arranged at such a timing as to make the master piston 46 make the maximum stroke when the piston 83 is at the top dead center position. When the position is near the dead center position, the third valve 28a is driven to open every time. That is, the third valve 28a also operates in two cycles such that the third valve 28a is driven to open every rotation of the crankshaft.

Therefore, during the operation of the engine auxiliary brake, the intake valve 27 and the third valve 28a operate at the valve timing shown in FIG. 8 (b). That is, the intake valve 27 begins to open immediately before the piston 83 reaches the top dead center (crankshaft rotation angle = 0 °), and is closed near the bottom dead center (crankshaft rotation angle = 180 °) of the piston 83 ( Inhalation stroke). After this, the piston 83
Rises to compress the air in the cylinder (compression stroke), and when it is near the top dead center (crankshaft rotation angle = 360 °) position, the third valve 28a opens to discharge the compressed air to the exhaust system, The intake valve 27 is opened again to suck air. At this time, the fuel injection is stopped as described above.

By thus operating the engine 20 as a pump and performing the negative work of compressing air, as in the first embodiment, the running energy of the vehicle is absorbed and the braking force is increased. It can be converted. In particular, by repeatedly performing such a pump operation for each rotation angle of the crankshaft of 360 ° (that is, for each rotation of the crankshaft), the engine auxiliary brake operates in two cycles. Greater absorption horsepower can be obtained.

Therefore, in the compression open type engine auxiliary brake device as the second embodiment of the present invention, it is possible to obtain a larger absorption horsepower and a stronger braking force than the normal engine auxiliary brake. There is. Further, in this compression open type engine auxiliary braking device, since the absorption horsepower can be increased, it is not necessary to provide a conventional exhaust braking device, and thus an excessive increase in exhaust pressure can be suppressed.

Therefore, it is possible to avoid a phenomenon in which the pressure in the exhaust manifold becomes too high due to the operation of the exhaust brake device and the exhaust valves of the other cylinders open (pressure adjustment lift). Further, conventionally, when the exhaust brake device and the compression opening type engine auxiliary brake device are used in combination, the set load (spring constant) of the valve spring of the exhaust valve 28 is set in order to prevent the pressure regulating lift as described above. Although it was necessary to set a large value, according to the compression opening type engine auxiliary brake device of the present invention, by eliminating the exhaust brake device, it is possible to avoid such an increase in the set load of the valve spring, and There is an advantage that the load on the valve train due to the strong set load of the spring can be reduced.

Further, by eliminating the exhaust brake device, it is possible to suppress an excessive rise in the exhaust temperature and to avoid wear of the scavenging air of the valve seat, especially the valve seat on the exhaust valve side. Further, by using the engine with the supercharger and the main compression pressure release type engine auxiliary braking device together, it is possible to expect an increase in intake pressure by the supercharger, and it is possible to further increase the absorption horsepower by the engine 20. There is also an advantage.

Further, since the intake air is sucked from the intake valve 27 and discharged to the exhaust system through the third valve 28a during the operation of this device, the exhaust system side like the conventional engine auxiliary braking device is used. Therefore, there is also an advantage that high temperature air and impurities (for example, NOx and particulates) after combustion of the fuel adhering to the exhaust system are prevented from flowing back into the combustion chamber again.

In the above-described second embodiment, the members denoted by the reference numerals, the description of which is omitted, are the same as the members having the same reference numerals as those in the first embodiment.
Next, a compression opening type engine auxiliary braking device as a third embodiment of the present invention will be described. This third embodiment is different from the compression opening type engine auxiliary braking device of the first and second embodiments described above. The exhaust means is mainly configured differently, and the other configurations are similar to those of the first and second embodiments.

That is, as shown in FIG. 9, an engine 20 equipped with the compression opening type engine auxiliary braking device of the third embodiment is equipped with an OHC type valve operating mechanism 23, and has two intake valves and two exhaust valves. It is configured as a 4-valve engine with valves. Although not shown in the figure, the engine 20
A well-known fuel supply device is provided. Here, the drive mechanism on the intake valve 27 side is configured similarly to the above-described first and second embodiments. That is, the rocker shaft 21A and the rocker arm 29 are integrally formed,
A rocker arm 70 is arranged at a position adjacent to the rocker arm 29 on the rocker shaft 21A.

Further, the rocker arm 70 is provided with a hydraulic piston mechanism 71, and the rocker arm 70 rotates integrally with the rocker shaft 21A so that the variable intake rocker arm 70 and the intake rocker arm 29 cooperate with each other. The variable intake rocker arm 70 is separated from the rocker shaft 21A and can be switched to a mode (non-cooperative mode) in which the variable intake rocker arm 70 is not linked to the rocker arm 29.

Specifically, when hydraulic oil is supplied into the rocker shaft 21A, the rocker arm 70 and the rocker arm 29 are connected via the pin member 73, and the supply of hydraulic oil into the rocker arm 21A is stopped. Then, the rocker arm 70 is separated from the rocker arm 29. Therefore, the rocker arm 70
When the rocker arm 29 is connected to the intake valve 27,
The rocker arm 70 and the rocker arm 29 are driven to be opened and closed by the intake cam 25 and the engine auxiliary brake cam 75 at a timing suitable for the operation of the engine auxiliary brake device.
When and are separated, the intake valve 27 is opened and closed by the intake cam 25 at a timing suitable for the valve timing during normal operation.

On the other hand, the exhaust valve 28, as shown in FIG.
The valve is driven to be opened by an exhaust rocker arm 30 which is integrally formed with the exhaust rocker shaft 21B.
Here, in the third embodiment, an exhaust roller arm 65 that operates during normal operation of the engine 20 and a variable exhaust rocker arm 65A that operates during operation of the compression opening type engine auxiliary braking device are provided in the drive system on the exhaust valve 28 side. The arms 65 and 65A are both rotatably supported by the exhaust rocker shaft 21B.

A hydraulic piston mechanism 66 is provided on the exhaust roller arm 65, and the variable exhaust rocker arm 65 is provided.
A hydraulic piston mechanism 66A is provided at A. Here, the hydraulic piston mechanism 66 is configured in the same manner as in the first and second embodiments, and has a rocker shaft 21B.
When the hydraulic oil is supplied to the inside, the pin member 68 is driven to drive the exhaust roller arm 65 and the exhaust rocker shaft 21B.
When the supply of the hydraulic oil into the rocker shaft 21B is stopped, the pin member 6 is released.
8 exhaust roller arm 65 and exhaust rocker shaft 2
1B is connected to the link mode.

On the other hand, the piston mechanism 66A of the variable exhaust rocker arm 65A is constructed similarly to the piston mechanism 71 of the variable intake rocker arm 70. That is,
This piston mechanism 66A corresponds to the hydraulic piston mechanism 6 described above.
6 operates in the opposite direction to the rocker shaft 21.
When the hydraulic oil is supplied into B, the variable exhaust roller arm 65 and the exhaust rocker shaft 21B are connected by the pin member 68A, and the linkage mode is set.
When the supply of hydraulic oil to the inside is stopped, the pin member 68A is driven to enter the non-coupling mode in which the exhaust roller arm 65 and the exhaust rocker shaft 21B are separated.

Therefore, when the supply of hydraulic oil into the rocker shaft 21B is stopped, the exhaust roller arm 65 and the exhaust rocker shaft 21B are connected, and the variable exhaust rocker arm 65A and the exhaust rocker shaft 21B are connected. The exhaust valve 28 is separated and the exhaust cam 26 is disconnected.
It will be opened and closed according to the cam profile of

When hydraulic oil is supplied into the rocker shaft 21B, the exhaust roller arm 65 and the exhaust rocker shaft 21B are separated, the variable exhaust rocker arm 65A and the exhaust rocker shaft 21B are connected, and the exhaust valve 28 is opened / closed according to the cam profile of the variable exhaust cam 31. The variable exhaust cam 31 will be described below.
Are provided on the camshaft 24, and the intake and exhaust cams 2
Like 5, 26, it is a cam that makes one rotation by two rotations of the crankshaft.

This variable exhaust cam 31 controls the exhaust valve 28 to open when the hydraulic piston mechanism 66A enters the linkage mode.
The variable exhaust cam 31 is formed so as to be driven to open the valve in a cycle. Therefore, the cam profile of the variable exhaust cam 31 has two cam peaks (see FIG. 4). Further, each crest portion has a 180 ° phase difference, and the cam profile of each cam crest portion is the same.

Further, the variable exhaust cam 31 has a piston 83.
Is arranged at a timing so as to drive the rocker arm 65A when the is at the top dead center position. Since the compression opening type engine auxiliary braking device according to the third embodiment of the present invention is configured as described above, the intake valve 27 and the exhaust valve 28 operate similarly to the first embodiment.

First, the normal operation of the engine 20 will be described. At this time, each rocker shaft 21A, 2
The hydraulic pressure supply to 1B is stopped. In this case, the hydraulic piston mechanism 71 on the intake rocker arm 29 side is in the non-coupling mode, the intake valve 27 is opened / closed according to the cam profile of the intake cam 25, and the valve opening operation is performed at a timing suitable for normal operation.

Further, in the exhaust rocker arm 30, the hydraulic piston mechanism 66 of the exhaust roller arm 65 is in the linkage mode, and the hydraulic piston mechanism 66A of the variable exhaust rocker arm 65A is in the non-coupling mode. Therefore, the rocker shaft 21B and the exhaust roller arm 65 are connected, and the rocker shaft-integrated exhaust rocker arm 30 is driven according to the cam profile of the exhaust cam 26, and the exhaust valve 28
Also performs the valve opening operation at a timing suitable for normal operation.

As a result, during such normal operation,
The intake / exhaust valves 27 and 28 operate at the valve timings shown in FIG. 5A and FIG. 8A to operate as a normal four-cycle engine. Next, the operation of the engine auxiliary braking device will be described. In this case, the fuel supply by the fuel supply device is stopped and the hydraulic oil is supplied into the rocker shafts 21A and 21B.

As a result, the hydraulic piston mechanism 71 on the intake rocker arm 29 side is controlled to the linkage mode, and the intake rocker shaft 21A and the variable intake rocker arm 70 are connected. Therefore, the intake valve 27 is driven to be opened and closed according to the cam profiles of the engine auxiliary brake cam 75 and the intake cam 25, and the intake valve 27 is opened each time the piston 83 is near the top dead center position. Will be driven.

In this case, the intake valve 27 operates in two cycles such that the intake valve 27 is opened every time the crankshaft rotates once. Further, in the exhaust rocker arm 30, the hydraulic piston mechanism 66 of the exhaust roller arm 65 is in the non-coupling mode,
Variable exhaust rocker arm 65A hydraulic piston mechanism 66A
Becomes the link mode.

Therefore, the rocker shaft 21B is separated from the exhaust roller arm 65 and connected to the variable exhaust rocker arm 65A, so that the exhaust rocker arm 30
Is driven according to the cam profile of the variable exhaust cam 31. As a result, the exhaust valve 28 is driven to open each time the piston 83 approaches the top dead center position. That is, the exhaust valve 28 also operates in two cycles such that the exhaust valve 28 is driven to open every crankshaft rotation.

Therefore, when the engine auxiliary brake is operated as described above, the intake valve 27 and the exhaust valve 28 are operated as shown in FIG.
It operates with the same characteristics as the valve timing shown in (b). By thus operating the engine 20 as a pump and performing the negative work of compressing air, the running energy of the vehicle can be absorbed and converted into a braking force.

In particular, the engine auxiliary brake is activated in two cycles by repeatedly performing such a pump operation every 360 ° of the crankshaft rotation angle (that is, every one rotation of the crankshaft). Therefore, a larger absorption horsepower can be obtained. Therefore, the compression opening type engine auxiliary braking device as the third embodiment of the present invention can also obtain the same operation and effect as those of the above-described first and second embodiments.

That is, there is an advantage that a larger absorption horsepower can be obtained and a stronger braking force can be obtained than that of a normal engine auxiliary brake. Further, in this compression opening type engine auxiliary braking device, since the absorption horsepower can be increased, it is not necessary to provide the exhaust braking device which has been often used together with the compression opening type engine auxiliary braking device in the related art. It is possible to suppress an excessive increase in exhaust pressure.

Therefore, it is possible to avoid the phenomenon that the pressure inside the exhaust manifold becomes too high due to the operation of the exhaust brake device and the exhaust valves of the other cylinders open (pressure adjustment lift). Further, conventionally, when the exhaust brake device and the compression opening type engine auxiliary brake device are used in combination, the set load (spring constant) of the valve spring of the exhaust valve 28 is set in order to prevent the pressure regulating lift as described above. Although it was necessary to set a large value, according to the compression opening type engine auxiliary brake device of the present invention, the exhaust brake device can be eliminated, and thus such an increase in the set load of the valve spring can be avoided. ,
There is an advantage that the load on the valve train due to the strong set load of the valve spring can be reduced.

Furthermore, by eliminating the exhaust brake device, it is possible to suppress an excessive rise in the exhaust temperature and to avoid wear of the scavenging air of the valve seat, especially the valve seat on the exhaust valve side. Further, by using the engine with the supercharger and the main compression pressure release type engine auxiliary braking device together, it is possible to expect an increase in intake pressure by the supercharger, and it is possible to further increase the absorption horsepower by the engine 20. There is also an advantage.

In addition, in the third embodiment, in addition to this, the hydraulic circuit 80 in the first and second embodiments is unnecessary, so that the overall size and weight of the apparatus can be reduced. Further, when the device is operated, the intake air is supplied to the intake valve 27.
Is taken from the exhaust system and exhausted to the exhaust system via the exhaust valve 28. Therefore, as in the conventional engine auxiliary braking device, high temperature air from the exhaust system side and impurities after combustion of fuel adhering to the exhaust system ( For example, it also has an advantage that NOx and particulates are prevented from flowing back into the combustion chamber again.

In the above-described third embodiment, the members denoted by the reference numerals, the description of which is omitted, are the same as the members having the same reference numerals as those in the first embodiment.
Further, the present compression opening type engine auxiliary braking device is not limited to the embodiment described above,
As long as it has a mechanism for switching the internal combustion engine that operates in a cycle to two cycles and operating the pump,
Other forms may be used.

Further, in each of the above-described embodiments, description is made using a diesel engine, but the present invention is not limited to such a diesel engine,
It can be widely applied to other types of engines such as, for example, a 4-cycle gasoline engine.

[0123]

As described in detail above, according to the compression opening type engine auxiliary braking device of the present invention as set forth in claim 1,
An intake valve is opened / closed between the combustion chamber and the intake system of the engine and is opened in the intake stroke of the engine during normal operation, and a normal operation of the engine is opened / closed between the combustion chamber and the exhaust system. In the exhaust stroke at the time, the exhaust means is opened to the exhaust state, and the fuel supply means for supplying the fuel to the combustion chamber is provided, and the exhaust by the exhaust means in the exhaust stroke is stopped during the predetermined operation of the engine. At the same time, exhaust adjusting means for causing the exhaust means to perform exhaust near the top dead center position of the piston, and intake valve drive adjusting means for opening the intake valve from near the top dead center position of the piston to near the bottom dead center position thereof. By absorbing the traveling energy of the vehicle by operating the engine as a pump, the fuel supply stopping means for stopping the fuel supply of the fuel supply means is provided. Can, it is possible to convert the running energy to the braking force. Further, when the engine is operated as a pump in this way, every 360 ° of the crankshaft rotation angle of the engine (that is, every one rotation of the crankshaft),
Can be operated in two cycles of intake and compression (exhaust), and there is an advantage that the braking force is significantly improved as compared with the conventional engine auxiliary braking device.

In addition, since the absorption horsepower can be increased in this way, it is not necessary to provide an exhaust brake device that is used in combination with a compression opening type engine auxiliary brake device to increase the braking force as compared with the conventional case. It is possible to suppress the excessive rise of the. Therefore, the internal pressure of the exhaust system becomes too high due to the operation of the exhaust brake device,
It is possible to avoid the phenomenon that the exhaust valves of the other cylinders are opened (pressure adjustment lift). Further, conventionally, when the exhaust brake device and the compression release type engine auxiliary brake device are used together, it is necessary to set a large set load (spring constant) of the valve spring of the exhaust valve in order to prevent a pressure adjustment lift. However, by eliminating the exhaust brake device, such an increase in the set load of the valve spring can be avoided, and the load on the valve train due to the strong set load of the valve spring can be reduced. There is an advantage.

Furthermore, by eliminating the exhaust brake device, it is possible to suppress an excessive rise in the exhaust temperature and to prevent the scavenging wear of the valve seat, especially the valve seat on the exhaust valve side. Further, when the present compression pressure release type engine auxiliary braking device is applied to an engine with a supercharger, an increase in intake pressure due to the supercharger can be expected, and the horsepower absorbed by the engine can be further increased. There is also an advantage.

Further, since the intake air at this time is sucked in from the intake valve and discharged from the exhaust means to the exhaust system, hot air from the exhaust system side to the exhaust system and exhaust system like the conventional engine auxiliary braking device. Impurities (for example, NOx and particulates) after the combustion of the adhered fuel are prevented from flowing back into the combustion chamber again. According to the compression opening type engine auxiliary braking device of the present invention as set forth in claim 2, in addition to the configuration of claim 1, the exhaust means drives the valve to open in an exhaust stroke during normal operation of the engine. An exhaust valve, wherein the exhaust adjusting means stops exhaust through the exhaust valve in an exhaust stroke of the engine during a predetermined operation of the engine, and controls the exhaust valve near the top dead center position of the piston. By being configured to open the valve, the engine valve system can be configured with two intake valves and two exhaust valves.
A valve-type engine can be easily configured, and an engine with excellent intake and exhaust efficiency can be obtained. Further, this makes it possible to increase the absorbed energy of the engine.

According to the compression open type engine auxiliary braking device of the present invention as defined in claim 3, in addition to the structure of claim 1, the exhaust means is provided in an exhaust stroke during normal operation of the engine. An exhaust valve that is driven to open, and a third valve that can separate communication between the combustion chamber and the exhaust system, separately from the exhaust valve, are provided, and the exhaust adjustment means is configured to operate during a predetermined operation of the engine. In the exhaust stroke of the engine, the exhaust through the exhaust valve is stopped, and the third valve is driven to open in the vicinity of the top dead center position of the piston, so that the air compressed by the engine is secured. In addition, it can be discharged to the exhaust system from the third valve. As a result, the absorption horsepower can be reliably improved.

According to the compression open type engine auxiliary braking device of the present invention as defined in claim 4, the above-mentioned claims 1 to 3 are also adopted.
In addition to the configuration described in any one of 1, the intake valve drive adjusting means opens the intake valve in the intake stroke by an intake cam provided on a cam shaft that rotates in conjunction with the crankshaft of the engine. At the same time, the intake valve can be reliably operated in two cycles with a simple configuration in which the intake valve is forcibly opened regardless of the movement of the intake cam during the expansion stroke. In particular, the present intake valve drive adjusting means is provided only by adding a mechanism for forcibly opening the intake valve during the expansion stroke to the structure for driving an ordinary intake valve that is driven by the intake cam during the intake stroke. Therefore, the intake valve drive adjusting means can be configured relatively easily, and an increase in cost and an increase in weight can be avoided.

According to the compression open type engine auxiliary braking device of the present invention as defined in claim 5, the above-mentioned claims 2-4 are also provided.
In addition to the configuration described in any one of 1, the exhaust means is configured as an exhaust valve that is driven to open by an exhaust cam provided on the camshaft during the exhaust stroke of the engine during normal operation. This device can be realized only by adding a configuration for driving the exhaust valve to open in the vicinity of the piston top dead center position of the compression stroke and the exhaust stroke with respect to the normal exhaust valve, and the present device can be realized at a relatively low cost. Can be configured.

According to the compression opening type engine auxiliary braking device of the present invention as defined in claim 6, in addition to the structure of claim 4 or 5, the intake valve drive adjusting means causes the intake cam to open. An intake rocker arm that transmits a valve drive force to the intake valve, an intake rocker shaft that rotates integrally with the intake rocker arm, and an intake valve that drives the intake valve to open in the expansion stroke of the engine that is disposed on the camshaft. A variable intake cam formed in a variable phase, a variable intake rocker arm that is loosely fitted to the intake rocker shaft and has an end portion in constant contact with the variable intake cam, and the intake rocker shaft and the variable intake rocker arm are engaged with each other. The configuration including the rocker arm engagement mechanism has an advantage that the intake valve drive adjusting means can be configured relatively easily.

According to the compression opening type engine auxiliary braking device of the present invention as set forth in claim 7, the above-mentioned claim 2, 4
In addition to the configuration according to any one of 1 to 6, an exhaust rocker arm that transmits the valve opening driving force of the exhaust cam to the exhaust valve by the exhaust adjusting means, and an exhaust rocker shaft that rotates integrally with the exhaust rocker arm. A variable exhaust cam disposed on the cam shaft and arranged in a phase such that the exhaust valve can be driven to open in the vicinity of the top dead center position of the piston in the compression stroke and the exhaust stroke; and the exhaust rocker shaft. Exhaust adjusting means is provided with a variable exhaust rocker arm that is loosely fitted and has an end in constant contact with the variable exhaust cam, and a rocker arm engagement mechanism that engages the exhaust rocker shaft and the variable exhaust rocker arm. Has the advantage that it can be configured relatively easily.

Further, according to the compression opening type engine auxiliary braking device of the present invention as defined in claim 8, the above-mentioned claims 2-6.
In addition to the configuration described in any one of,
An exhaust rocker arm that transmits the valve opening driving force of the exhaust cam to the exhaust means, an exhaust rocker shaft that rotates integrally with the exhaust rocker arm, and a compression stroke and an exhaust stroke that are disposed on the cam shaft. , A variable exhaust cam disposed in a phase in which the valve is driven to open in the vicinity of the top dead center position of the piston, a push-down mechanism provided above the exhaust means and pressing down the exhaust valve, and reciprocating by the variable exhaust cam. The piston member and the fluid circuit that connects the piston member and the push-down mechanism to each other are connected to each other, so that when the exhaust adjusting means operates, the exhaust means operates reliably when the piston is near the top dead center position. Operates to expel compressed air in two cycles. This has the advantage that the engine can be reliably pumped in two cycles.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a main part of a compression opening type engine auxiliary braking device according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing a compression opening type engine auxiliary braking device according to the first embodiment of the present invention,
It is an AA sectional view in FIG.

FIG. 3 is a schematic cross-sectional view showing a compression opening type engine auxiliary braking device according to the first embodiment of the present invention,
It is a BB sectional view in FIG.

FIG. 4 is a schematic cross-sectional view showing a compression opening type engine auxiliary braking device according to the first embodiment of the present invention,
It is CC sectional drawing in FIG.

FIG. 5 is a diagram for explaining the operating characteristics of the compression opening type engine auxiliary braking device according to the first embodiment of the present invention, in which (a) is a diagram showing a valve operating timing during normal operation of the engine; (B) is a diagram showing a valve actuation timing when the present apparatus is actuated.

FIG. 6 is a schematic acupressure diagram for explaining operating characteristics of the compression open type engine auxiliary braking device according to the first embodiment of the present invention.

FIG. 7 is a schematic configuration diagram showing a main part of a compression opening type engine auxiliary braking device as a second embodiment of the present invention, and is a diagram corresponding to FIG. 1.

FIG. 8 is a diagram for explaining the operating characteristics of the compression opening type engine auxiliary braking device according to the second embodiment of the present invention, in which (a) is a diagram showing a valve operating timing during normal operation of the engine; (B) is a diagram showing a valve actuation timing when the present apparatus is actuated.

FIG. 9 is a schematic configuration diagram showing a main part of a compression open type engine auxiliary braking device according to a third embodiment of the present invention, and is a diagram corresponding to FIG. 1.

FIG. 10 is a schematic acupressure diagram for explaining operating characteristics of an engine including a general engine auxiliary braking device and an exhaust braking device.

[Explanation of symbols]

20 engine 21 rocker shaft 21A intake rocker shaft 21B exhaust rocker shaft 23 valve mechanism 24 camshaft 25 intake cam 26 exhaust cam 27 intake valve 28 exhaust valve (exhaust means) 28a third valve (exhaust means) 29 intake rocker arm 30 exhaust rocker arm 31 Variable Exhaust Cam 34 Intake Valve Bridge 35 Exhaust Valve Bridge 35 39 Oil Path Forming Body 40 Slave Piston (Pushing Mechanism) 41 Hydraulic Oil Path 42 Distribution Path 44 Control Valve 441 Space 442 Return Spring 443 Opening 45 Sonorade Valve 46 Master piston (piston member) 48 Return spring 53 Hole 54 Return spring 55 Stopper 60-62 Bearing member 63, 64, 64A Roller 65 Exhaust roller arm 65A Variable Exhaust rocker arm 66, 66A Hydraulic piston mechanism (rocker arm engagement mechanism) 67 Hole 68, 68A Pin member 69 hole 70 Variable intake rocker arm 71 Hydraulic piston mechanism (rocker arm engagement mechanism) 72 Hole 73 Pin member 74 Hole 75 Engine auxiliary brake Cam (variable intake cam) 76 roller 80 fluid circuit 81 engine control unit (ECU) 82 pump 83 piston 90 intake valve drive adjusting means 91 exhaust adjusting means

Claims (8)

[Claims] 1. An intake valve that opens and closes between a combustion chamber of an engine and an intake system and is opened and closed during an intake stroke of the engine during normal operation, and opens and closes between the combustion chamber and an exhaust system. The engine includes exhaust means for opening to an exhaust state during an exhaust stroke of the engine during normal operation, and fuel supply means for supplying fuel to the combustion chamber, and the exhaust means during the exhaust stroke during a predetermined operation of the engine. And an exhaust adjusting means for stopping the exhaust by the exhaust means near the top dead center position of the piston and an intake valve for opening the intake valve from near the top dead center position to near the bottom dead center position of the piston. A compression opening type engine auxiliary braking device comprising valve drive adjusting means and fuel supply stopping means for stopping the fuel supply of the fuel supply means. 2. The exhaust means is an exhaust valve that is driven to open in an exhaust stroke during normal operation of the engine, and the exhaust adjusting means is provided in the exhaust stroke of the engine during a predetermined operation of the engine. The compression opening type engine auxiliary brake according to claim 1, wherein the exhaust valve is configured to stop the exhaust through the exhaust valve and drive the exhaust valve to open in the vicinity of the top dead center position of the piston. apparatus. 3. The exhaust means can cut off the communication between the combustion chamber and the exhaust system separately from the exhaust valve that is driven to open during an exhaust stroke of the engine during normal operation. A third valve, the exhaust adjusting means stops the exhaust through the exhaust valve in the exhaust stroke of the engine during a predetermined operation of the engine, and controls the third valve in the vicinity of the top dead center position of the piston. The compression-opening type engine auxiliary braking device according to claim 1, wherein the compression-opening type engine auxiliary braking device is configured to be driven to open. 4. The intake valve drive adjusting means opens the intake valve in the intake stroke by an intake cam provided on a camshaft that rotates in conjunction with the crankshaft of the engine, and in the expansion stroke, The compression opening type engine auxiliary braking device according to any one of claims 1 to 3, wherein the intake valve is forcibly opened regardless of the movement of the intake cam. 5. The exhaust means is configured as an exhaust valve that is driven to open by an exhaust cam provided on the cam shaft during the exhaust stroke of the engine during normal operation. Item 5. A compression open type engine auxiliary braking device according to any one of items 2 to 4. 6. The intake valve drive adjusting means, an intake rocker arm for transmitting the valve opening drive force of the intake cam to the intake valve, an intake rocker shaft rotating integrally with the intake rocker arm, and an upper part of the cam shaft. And a variable intake cam formed in a phase capable of driving the intake valve to open during the expansion stroke of the engine, and a variable intake cam that is loosely fitted to the intake rocker shaft and has an end constantly contacting the variable intake cam 6. The compression release type engine auxiliary braking device according to claim 4, further comprising: an intake rocker arm, and a rocker arm engagement mechanism for engaging the intake rocker shaft and the variable intake rocker arm. 7. The exhaust adjusting means includes an exhaust rocker arm for transmitting a valve opening drive force of the exhaust cam to the exhaust valve, an exhaust rocker shaft rotating integrally with the exhaust rocker arm, and an exhaust rocker shaft arranged on the cam shaft. A variable exhaust cam disposed in a phase in which the exhaust valve is opened and driven in the vicinity of the top dead center position of the piston in the compression stroke and the exhaust stroke; 7. A variable exhaust rocker arm that is in constant contact with the variable exhaust cam, and a rocker arm engagement mechanism that engages the exhaust rocker shaft and the variable exhaust rocker arm. A compression opening type engine auxiliary braking device described in (1). 8. The exhaust adjusting means includes an exhaust rocker arm for transmitting a valve opening driving force of the exhaust cam to the exhaust means, an exhaust rocker shaft rotating integrally with the exhaust rocker arm, and an exhaust rocker arm arranged on the cam shaft. A variable exhaust cam arranged in a phase in which the exhaust means is opened and driven in the vicinity of the top dead center position of the piston in the compression stroke and the exhaust stroke; and the exhaust valve is provided above the exhaust means and pushes down the exhaust valve. 7. A push-down mechanism, a piston member that reciprocates by the variable exhaust cam, and a fluid circuit that connects and connects the piston member and the push-down mechanism.
The compression-release type engine auxiliary braking device according to any one of 1.