JPH07189636A - Synchronous engine brake device - Google Patents

Abstract

PURPOSE:To promote miniaturization of a device by assembling a means for synchronizing a control valve with operation of an engine into an engine main body, in an engine brake device for increasing engine brake performance in its expansion stroke by discharging air in a combustion chamber in the vicinity of a compressing stroke top dead point. CONSTITUTION:A synchronous engine brake device is provided with a control valve 9 for opening/closing a pressure discharging passage 8 which is communicated with a combustion chamber 3 and a valve driving mechanism 31 for discharging compressed air in the combustion chamber 3 from a pressure discharging passage 8 by opening the control valve 9 in the vicinity of a compressing stroke top dead point. The valve driving mechanism 31 is provided with a oil pressure source, a hydraulic cylinder for driving the control valve 9 which is provided on a cylinder head 30, an oil passage 34 for connecting the oil pressure source and the hydraulic cylinder 33 to each other, an axial valve 35 which is provided on the cylinder head 30 so as to cross with the oil passage 34, and a synchronous mechanism 37 for synchronizing opening the axial valve 35 in the vicinity of the compressing stroke top dead point by connecting the axial valve 35 and the synchronous driving system 43 of an internal combustion engine to each other mechanically.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention opens a control valve provided in a pressure release passage in an internal combustion engine near the top dead center of a compression stroke to release air in a combustion chamber to improve engine braking ability in an expansion stroke. More specifically, the present invention relates to an engine brake device, and more particularly to a synchronous engine brake device that drives a control valve in a synchronous manner by mechanically coupling the control valve with a synchronous drive system such as a cam gear or a reiming gear of an internal combustion engine. .

[0002]

2. Description of the Related Art In a normal engine brake of an internal combustion engine (hereinafter, also simply referred to as an engine), a piston is pushed up in a compression stroke. At this time, a force that pushes the piston down due to compressed air acts and this This is the so-called engine braking force. However, in the subsequent expansion stroke, the force of pushing down the piston by the compressed air acts, and this force acts to accelerate the pushing down of the piston in the expansion stroke, so the braking force obtained in the compression stroke is lost and weakens. , The engine braking performance is deteriorated.

Therefore, in order to eliminate such deterioration of engine braking performance, an engine braking device called, for example, a power tard has been developed. This engine brake device is provided with an engine brake control valve [a third valve having a small diameter (third valve)] different from a normal intake valve and an exhaust valve, and this third valve is provided near the top dead center of the compression stroke of the internal combustion engine. By opening the valve by hydraulically driving and releasing the compressed air in the combustion chamber from the pressure release passage, the engine braking force in the compression stroke is directly acted as the engine braking force without being lost in the expansion stroke. It is a device designed to greatly increase the engine braking ability.

For example, FIG. 5 shows a conventional engine braking device. In FIG. 5, 1 is a cylinder, 2 is a piston, 3 is a combustion chamber, 4 is an intake passage, 5 is an exhaust passage, 6 is an intake valve, and 7 is an intake valve. Is an exhaust valve. A pressure release passage 8 is provided on the side of the opening of the exhaust passage 5 so as to bypass this portion, and a third valve 9 is provided in the pressure release passage 8.

The third valve 9 is driven by a driven piston 10 which is hydraulically driven, and an oil pump for supplying working oil (here, engine oil) to an oil chamber 11 at the end of the driven piston 10. 12 and a control valve 13 for discharging the hydraulic oil in the oil chamber 11 to the oil pan. In addition, 14 is a relief valve which stabilizes the hydraulic pressure of the operating oil supplied.

The control valve 13 is pneumatically driven, and an air passage 16A for communicating the air tank 15 with the air cylinder 13A of the control valve 13.
And a solenoid valve 17 which is provided in the air passage 16A and has a mode for guiding the air from the air tank 15 to the air cylinder 13A and a mode for discharging the air from the air cylinder 13A.

An exhaust brake valve 18 is provided in the exhaust passage 5, and the exhaust brake valve 18 is provided.
A control valve 19 for controlling opening and closing is provided. This control valve 19 is also pneumatically driven, and the air tank 15 and this control valve 19
Air passage 16B communicating with the air cylinder (not shown)
And a mode in which the air from the air tank 15 is introduced into the air passage 16B to guide the air to the air cylinder of the control valve 19 to close the exhaust brake valve 18, and the air in the air cylinder is discharged to open the exhaust brake valve 18. And a solenoid valve 20 having a mode.

The solenoid valves 17 and 20 are electronically controlled by an electronic control circuit 21 as shown in FIG. In the electronic control circuit 21, 21A
Is a battery, 21B is a starter switch, 21C is a fusible link, 21D is an interlock switch, 21
E is a clutch switch, 21F is a power tart switch, 21G is an accelerator micro switch equipped for mechanical governor specifications, 21H is a power controller, 21J is a power relay, and 21K is a micro switch equipped for electronic governor specifications, 21L. Is an electronic governor or electronic timer controller, 21M is a tachometer,
21N is a tachometer sensor, 21P is a push lock switch, and 21Q is a power indicator lamp.

With this configuration, it is possible to set a mode in which only the power turd (that is, the engine brake auxiliary operation by the third valve) is operated as the engine brake, and a mode in which the power turd and the exhaust brake are used in combination. Has become. The operation of each of these modes is as follows. That is, when operating only the power tard, the clutch switch 21E, the power tattered switch 21F, the accelerator micro switch 21G, and the power tattered controller 21L are all near the top dead center of the compression stroke of the engine as shown in FIG. The condition is that it is in the on state, and if any one of these is in the off state, the power tard does not operate. Further, the push lock switch 21P is turned off. As a result, the solenoid valve 17 is energized and air is supplied to the control valve 13 to close it. Then, the hydraulic pressure in the oil chamber 11 is increased, the driven piston 10 is driven downward in FIG. 5, the third valve 9 is driven to be opened, and power tard (that is, engine brake assist operation by the third valve) is performed. On the other hand, since the solenoid valve 17 is not energized, no air is supplied to the control valve 19 and the exhaust brake valve 18 is held in the open state, and the exhaust brake does not work.

When the power turd and the exhaust brake are used in combination, as shown in FIG. 6, in addition to the switch condition for activating only the power turd, the push lock switch 21P is turned on. However, an engine braking device that controls the timing by such electronic control has a complicated structure and causes an increase in cost. Therefore, for example, Japanese Utility Model Publication No. 2-19526 and Japanese Utility Model Publication No. 61-61.
No. 152740, the hydraulic drive system for the third valve is mechanically linked to the operation of the engine so that the third valve has a required timing (ie, near the top dead center of the compression stroke of the engine).
There is disclosed an engine braking device configured to be operated at.

[0011]

However, in the means disclosed in the above-mentioned respective publications, a mechanism (referred to as a synchronizing means) for mechanically coordinating the hydraulic drive system of the third valve with the operation of the engine is different from the engine body. Only the structure formed separately is disclosed, and there is a problem that the device is likely to be upsized.

The present invention was devised in view of the above-mentioned problems, and by incorporating means for synchronizing the engine brake control valve with the operation of the engine in the engine body, it is possible to promote the miniaturization of the device. An object of the present invention is to provide a type engine braking device.

[0013]

Therefore, the synchronous engine brake device of the present invention is provided with a pressure release passage communicating with a combustion chamber of an internal combustion engine, and a control valve for controlling the engine brake by opening / closing the pressure release passage. And a valve drive mechanism for hydraulically opening the control valve near the top dead center of the compression stroke of the internal combustion engine to release the compressed air in the combustion chamber from the pressure release passage, the expansion stroke of the internal combustion engine In the engine braking device for increasing the engine braking ability in the above, the valve drive mechanism supplies a hydraulic pressure source for pressurizing the hydraulic fluid and a hydraulic fluid for hydraulically driving the control valve provided in the cylinder head. A hydraulic cylinder to be supplied, an oil passage formed in the cylinder head for connecting the hydraulic pressure source and the hydraulic cylinder, and a rotating head for rotating the cylinder head so as to intersect the oil passage. An axial valve equipped with a supply mode for supplying hydraulic oil to the hydraulic cylinder and a discharge mode for discharging hydraulic oil from the hydraulic cylinder; a synchronous drive system for the axial valve and the internal combustion engine; Is mechanically coupled to the shaft-shaped valve so as to bring the shaft-like valve into the supply mode in the vicinity of the top dead center of the compression stroke of the internal combustion engine.

[0014]

In the above-described synchronous engine brake device of the present invention, in the valve drive mechanism, the synchronous mechanism mechanically couples with the synchronous drive system of the internal combustion engine to move the axial valve in the compression stroke of the internal combustion engine. Set the supply mode near the dead point. Therefore, hydraulic oil is supplied from the oil passage to the hydraulic cylinder through the axial valve, the control valve is hydraulically driven to open, and the pressure release passage opens near the top dead center of the compression stroke of the internal combustion engine to open the combustion chamber. Compressed air is discharged from this pressure discharge passage.

In this way, the compressed air compressed in the compression stroke is released, so that in the subsequent expansion stroke,
A force that resists pushing down the piston comes to act, and in addition to the engine braking force obtained in the compression stroke, the engine braking force can be obtained in the expansion stroke as well.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A synchronous engine braking device as an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view of a cylinder block of an internal combustion engine equipped with the device, and FIG. A perspective view showing the end of the axial valve,
FIG. 3 is a perspective view showing the axial valve, and FIG. 4 is a schematic transverse sectional view of the axial valve.

As shown in FIG. 1, a cylinder 1 is provided in this internal combustion engine (a diesel engine in this example), and a plurality (four in this example) of cylinders 1 are arranged in a direction perpendicular to the plane of the drawing. They are arranged side by side in series. The engine braking device called a power tard is provided so that it can operate in each cylinder unit. That is, a piston (not shown) is housed in each cylinder, and the combustion chamber 3 is formed above the piston. In the cylinder block 30 above the combustion chamber 3, the intake passage 4 and the exhaust passage 5 are provided.
Are formed, and an intake valve (not shown) and an exhaust valve 7 are provided respectively. A pressure release passage 8 is formed at the side of the opening (exhaust port inlet) of the exhaust passage 5 so as to bypass this portion.
Is provided with an engine brake control valve [small-diameter third valve (third valve)] 9. The intake valve is not shown.

A hydraulic valve drive mechanism 31 is provided to drive the third valve 9, and the valve drive mechanism 31 is used.
Is a return spring 3 that biases the third valve 9 toward the closing side.
2, an oil pump (not shown) that is a hydraulic pressure source that supplies pressurized hydraulic oil, and a driven piston 10 that is hydraulically driven by the hydraulic oil from the oil pump and presses the third valve 9 to the open side.
And a hydraulic cylinder 33 equipped with the driven piston 10,
An oil passage 34 arranged from the oil pump to the hydraulic cylinder 32, and a shaft-shaped valve 3 interposed in the middle of the oil passage 34.
5, a discharge oil passage 36 arranged from the shaft-shaped valve 35 to an oil tank (not shown), and a synchronization mechanism 37 that drives the shaft-shaped valve 35 in synchronization with the operation of the engine.

As shown in FIGS. 2 and 3, the shaft-shaped valve 35 is rotatably provided in a shaft hole 38 formed so as to pass through the upper cylinders of the cylinder block 30 in a direction intersecting with the oil passage 34. A hole 39 forming a part of the oil passage 34 is bored in the shaft center portion, and an opening 3 communicating with the hole 39 is formed in the shaft end portion.
9A is formed. As shown in FIG. 1, an upstream portion of the oil passage 34 is connected to the opening 39A.

As shown in FIGS. 2 to 4, hydraulic oil supply ports 40 are provided in the portions of the shaft-shaped valve 35 corresponding to the respective cylinders.
A hydraulic oil discharge port 41 is arranged with a phase set for each cylinder. Each hydraulic oil supply port 40 communicates with the hole 39 through a passage 42. Then, as shown in FIG. 4 (a), the axial valve 35 has a hydraulic oil supply port 40.
A hydraulic oil supply mode in which the fluid is communicated with the downstream side of the oil passage 34,
As shown in FIG. 4B, a hydraulic oil discharge mode is established in which the downstream side of the oil passage 34 and the discharge oil passage 36 are communicated with each other through the hydraulic oil discharge port 41.

That is, in a certain cylinder, in synchronism with the piston coming near the top dead center of the compression stroke, the axial valve 35 enters the hydraulic oil supply mode shown in FIG. 4 (a),
The hydraulic oil supply port 40 communicates with the downstream side of the oil passage 34, hydraulic oil is supplied to the hydraulic cylinder 33, and the driven piston 10 moves to press the third valve 9 to the open side. As a result, the pressure release passage 8 is opened. After this compression stroke, the axial valve 35 enters the hydraulic oil discharge mode shown in FIG.
Of the hydraulic oil in the hydraulic cylinder 33 is discharged, the driven piston 10 returns to its original state, and the third valve 9 is closed by the return spring 32.
The pressure release passage 8 is closed.

The synchronizing mechanism 37 is for synchronizing the axial valve 35 with the operation stroke of the engine in this way,
Here, the structure is such that the end of the shaft-shaped valve 35 is provided with a synchronous gear 44 mechanically coupled (here, meshed) with a synchronous drive system of an internal combustion engine, such as a cam gear or a timing gear 43. There is. Since the synchronous engine braking device as one embodiment of the present invention is configured as described above, when the engine is operated, the synchronous gear 44 and The axial valve 35 rotates.

The working oil supply port 40 and the working oil discharge port 41 of the shaft-shaped valve 35 are set to the working oil supply mode position when the piston comes close to the top dead center of the compression process for each cylinder. Since it is set to the hydraulic oil discharge mode position after passing, the hydraulic oil is supplied from the oil passage 34 to the hydraulic cylinder 33 through the axial valve 35 in the vicinity of the top dead center of the compression stroke in each cylinder, and the control is performed. The valve 9 is hydraulically driven to open. As a result, the pressure release passage 8 is opened near the top dead center of the compression stroke, and the compressed air in the combustion chamber 3 is released from the pressure release passage 8.

In this way, the compressed air compressed in the compression stroke is released, so that in the subsequent expansion stroke,
A force that resists pushing down the piston comes to act, and in addition to the engine braking force obtained in the compression stroke, the engine braking force can be obtained in the expansion stroke as well. In other words, in the compression stroke, the compressed air acts to resist the push-up of this piston against the push-up of the piston, and becomes the engine braking force, and in the expansion stroke after that,
Since compressed air was released at the end of the compression stroke, the discharged and thinned air acts to resist the depression of the piston against the depression of the piston, which also serves as the engine braking force.

Although the engine braking force is greatly improved in this way, this device may also appropriately use an exhaust brake as described in the conventional example. Further, in the present device, the synchronization mechanism 37 is a mechanical type, the controller is not required, the configuration is simple, and there is no malfunction, and many of its components including the axial valve 35 are formed in the engine body. Therefore, there is an advantage that the device can be configured without increasing the size of the engine.

[0026]

As described in detail above, according to the synchronous engine brake device of the present invention, the pressure release passage communicating with the combustion chamber of the internal combustion engine and the engine release is controlled by opening and closing the pressure release passage. The internal combustion engine includes a control valve and a valve drive mechanism for hydraulically opening the control valve near the top dead center of the compression stroke of the internal combustion engine to release the compressed air in the combustion chamber from the pressure release passage. In an engine braking device for increasing engine braking capacity in an expansion stroke, the valve drive mechanism includes an oil pressure source for pressurizing hydraulic oil and an operation for hydraulically driving the control valve provided in the cylinder head. A hydraulic cylinder supplied with oil, an oil passage formed in the cylinder head for connecting the hydraulic source and the hydraulic cylinder, and rotation of the cylinder head so as to intersect the oil passage. A shaft-shaped valve that is installed in the hydraulic cylinder and has a supply mode for supplying hydraulic oil to the hydraulic cylinder and a discharge mode for discharging hydraulic oil from the hydraulic cylinder; and a synchronous drive system for the shaft-shaped valve and the internal combustion engine. And a synchronous mechanism that mechanically couples the axial valve into the supply mode in the vicinity of the compression stroke top dead center of the internal combustion engine.
In addition to the engine braking force obtained in the compression stroke, the engine braking force can be obtained in the expansion stroke as well, resulting in a significant improvement in engine braking performance.
It can be obtained at a relatively low cost without increasing the size of the entire engine.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a cylinder block showing a synchronous engine braking device as an embodiment of the present invention.

FIG. 2 is a perspective view showing an end portion of a shaft-shaped valve of a synchronous engine braking device as one embodiment of the present invention.

FIG. 3 is a perspective view showing a shaft-shaped valve of a synchronous engine braking device as one embodiment of the present invention.

FIG. 4 is a cross-sectional view showing the operation of the shaft-shaped valve of the synchronous engine braking device as one embodiment of the present invention, (a) showing a supply mode and (b) showing a discharge mode.

FIG. 5 is a configuration diagram showing a conventional engine braking device.

FIG. 6 is a diagram showing an operating state of a conventional engine braking device.

FIG. 7 is a diagram showing another operating state of the conventional engine braking device.

[Explanation of symbols]

1 cylinder 3 combustion chamber 4 intake passage 5 exhaust passage 7 exhaust valve 8 pressure release passage 9 engine brake control valve [third valve (third valve)] 10 driven piston 30 cylinder block 31 valve drive mechanism 32 return spring 33 hydraulic cylinder 34 oil Passage 35 Axial valve 36 Discharge oil passage 37 Synchronous mechanism 38 Shaft hole 39 Hole 39A opening 40 Hydraulic oil supply port 41 Hydraulic oil discharge port 42 Passage 43 Cam gear or timing gear (synchronous drive system of internal combustion engine) 44 Synchronous gear

Claims (1)

[Claims] 1. A pressure release passage communicating with a combustion chamber of an internal combustion engine, a control valve for opening and closing the pressure release passage to control engine braking, and the control valve near the top dead center of a compression stroke of the internal combustion engine. Is provided with a valve drive mechanism that releases the compressed air in the combustion chamber from the pressure release passage by hydraulically releasing the engine to increase the engine braking capacity in the expansion stroke of the internal combustion engine. The valve drive mechanism connects a hydraulic pressure source for pressurizing hydraulic oil, a hydraulic cylinder provided in the cylinder head and supplied with hydraulic oil for hydraulically driving the control valve, and the hydraulic pressure source and the hydraulic cylinder. An oil passage formed in the cylinder head, a supply mode in which the cylinder head is rotatably provided so as to intersect with the oil passage, and the hydraulic oil is supplied to the hydraulic cylinder; A shaft-shaped valve having a discharge mode for discharging hydraulic oil from a pressure cylinder, and the shaft-shaped valve and the synchronous drive system of the internal combustion engine are mechanically coupled to each other to mechanically connect the shaft-shaped valve to the internal combustion engine. A synchronous engine brake device, comprising: a synchronization mechanism that sets the supply mode near the top dead center of the compression stroke.