JP4088782B2 - Valve stop device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a valve deactivation device for an internal combustion engine, and more particularly to a valve deactivation device for an internal combustion engine having a valve deactivation mechanism for deactivation operation.
[0002]
[Prior art]
Generally, in a multi-cylinder internal combustion engine (hereinafter referred to as an engine), a cylinder resting operation may be performed. In this way, if the operation of the valve that opens and closes the cylinder is completely stopped, gas exchange is not performed, pumping loss is reduced, and fuel efficiency is improved.
[0003]
In a gasoline engine or a diesel engine for a passenger car, for example, when it is desired to perform a cylinder deactivation operation for several cylinders, for example, variable valve timing (VVT) such as a cam switching type, a continuously variable lift type, a hydraulic electromagnetic type, etc. A valve operating device such as a mechanism is used. This is because these engines have a wide range of operating rotational speeds, and there are strong demands for variable valve timing and lift in view of engine performance requirements. In other words, the cylinder resting operation generally exists as one method of using a complicated variable valve system mechanism.
[0004]
By the way, in large-sized diesel engines for commercial vehicles, in recent years, in order to meet market demands such as improvement of fuel consumption and reduction of exhaust gas, a cylinder-free operation is desired. For example, if cylinder resting operation is performed when the engine is operating at a low load, fuel consumption is reduced by reducing pumping loss and in-cylinder pressure (net average effective pressure (Pme)), or exhaust gas aftertreatment by increasing exhaust temperature This is because early activation of the device can be expected.
[0005]
However, in the case of a large diesel engine, the operating rotational speed range of the engine is narrow and there is no strong demand for variable valve timing. It is difficult to say that it is optimal in terms of reliability and the like.
Here, a technique of a valve stop apparatus for an internal combustion engine that performs a cylinder resting operation in a multi-cylinder diesel engine has been proposed, and according to the apparatus, the valve stop apparatus can be simplified ( For example, see Patent Document 1).
[0006]
[Patent Document 1]
JP 61-241409 (page 2, lower left column, line 4 to page 3, lower left column, line 9, FIGS. 1 to 3)
[0007]
[Problems to be solved by the invention]
By the way, in the valve stop device of the prior art, a bridge guide shaft provided with an oil passage arranged in the cylinder head and supplied with hydraulic oil, and a bridge arranged via the bridge guide shaft to operate the valve, A cylinder body screwed into the bridge and provided with an oil passage, a metal slidably inserted into the bridge, and when the hydraulic oil is supplied in one direction, it contacts the metal While the gold movement is transmitted to the bridge to operate the valve, when hydraulic fluid is supplied in the other direction, the contact with the gold is released and the valve is stopped without transmitting the gold movement to the bridge. And a piston having a slide plate and a rod for switching between them.
[0008]
Therefore, according to the conventional technique, it is possible to perform the cylinder resting operation with the diesel engine, but the oil passage is formed in the cylinder body that moves together with the bridge, and the slide body and the rod are provided in the cylinder body. Since the piston is arranged, the cylinder resting mechanism is complicated, and there is a problem that a large space is required and the compactness is lacking. In addition, if the rod becomes longer, a problem arises in response.
[0009]
Furthermore, since the contact between the metal and the slide plate is continued during normal valve operation, there is a problem that the rod is easily bent and the durability is poor. In addition, since the valve is operated and stopped by switching the oil passage, for example, when hydraulic oil is not supplied from the engine side, there is a problem that neither can be performed.
[0010]
That is, in the prior art, no special consideration is given to cost, reliability, and the like when the cylinder resting operation is performed.
The present invention has been made in view of such a problem, and an object thereof is to provide an engine valve deactivation device capable of performing a cylinder deactivation operation of an internal combustion engine while reducing cost and improving reliability. And
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a valve suspension apparatus for an internal combustion engine according to claim 1 is provided with a cylinder head provided with a valve for opening and closing the inside of the cylinder, and a hydraulic oil from a hydraulic source inside the cylinder head. A shaft having a supply oil passage for supplying the valve, a valve bridge that is slidably fitted to the shaft and that opens and closes the valve, and is slidably fitted between the outside of the shaft and the inside of the valve bridge In addition, it has an oil chamber that communicates with the supply oil passage and stores hydraulic oil, and is provided in the inner piston that is displaced according to the rotation of the cam shaft of the engine, and is operated according to the operating conditions of the engine. When oil is supplied, it engages with the valve bridge to transmit the movement of the inner piston to the valve bridge to operate the valve. On the other hand, when the supply of hydraulic oil is released, the valve A switching means for stopping the operation of the valve without transmitting the movement of the inner piston to the valve bridge without sliding the inner piston, and a pressure releasing means for releasing the hydraulic oil in the oil chamber. It is characterized by providing.
[0012]
Therefore, according to the valve suspension apparatus of the first aspect, the oil chamber is not provided on the side of the valve bridge requiring rigidity, but the oil chamber is provided in the inner piston located inside the valve bridge, and the valve is connected to the inner piston. Since the switching means between the operation and the stop is provided, the cylinder resting mechanism is simplified, space is saved, and compactness is achieved.
[0013]
Further, since the switching means transmits the movement of the inner piston to the valve bridge by engagement with the valve bridge only during normal valve operation, durability is improved.
In addition, it is possible to install a valve suspension system with reduced cost and improved reliability on an existing large diesel engine. By performing suspension operation at low load, fuel efficiency and exhaust temperature can be improved. As a result, an early activation of the exhaust gas aftertreatment device is achieved.
[0014]
Further, the invention according to claim 2 is characterized in that the switching means is composed of a plurality of engaging members protruding and retracting by supplying and releasing the hydraulic oil.
Thus, by using a plurality of engaging members as the switching means, the engagement and release of the switching means become reliable and reliable.
The invention according to claim 3 is characterized in that the depressurizing means is provided at a tip portion of the inner piston facing the position where the shaft is disposed.
[0015]
Thereby, the pressure in an inner piston is adjusted appropriately, and the operation | movement and a stop of the valve | bulb by a switching means are implemented reliably. Also, the oil discharged by depressurization enables lubrication around the valve bridge.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment when the present invention is applied to a diesel engine will be described with reference to the drawings.
FIG. 1 is a partial configuration diagram of an engine to which a valve suspension device of a diesel engine (hereinafter referred to as an engine) according to an embodiment of the present invention is applied. 2 is a cross-sectional view of the valve stop device, and FIGS. 3 and 4 are enlarged cross-sectional views of the main part of the valve stop device. Hereinafter, the internal combustion engine according to the present invention will be described with reference to FIGS. The configuration of the valve stop device will be described.
[0017]
The engine of this embodiment is composed of multiple cylinders, and a cylinder head 1 located above one cylinder is provided with a total of four intake valves and exhaust valves for opening and closing the inside of the cylinder. As an example, as shown in FIG. 1, the cylinder head 1 includes an intake port 2 for introducing intake air or the like into the cylinder, and two intake valves 4 for opening and closing an intake port that communicates the intake port 2 and the cylinder. 4 are provided. Note that illustration of the two exhaust valves is omitted.
[0018]
The intake valve 4 is arranged upward via a valve guide 3 implanted in the cylinder head 1, and a valve support 5 is provided at the upper end of the intake valve 4. Valve springs 6, 6 are interposed between the valve support 5 and the cylinder head 1, and a cylinder resting device 10 is provided above the valve support 5.
Between the intake valves 4 and 4, a shaft 7 planted upward from the cylinder head 1 is disposed. On the central axis in the shaft 7, there is provided a supply oil passage 8 that supplies hydraulic oil related to the operation and suspension of the intake valves 4 and 4 to the cylinder resting device 10. The supply oil passage 8 is connected to a supply oil passage 9 provided inside the cylinder head 1, and hydraulic oil (engine oil) from a hydraulic source is supplied from the engine side via an ON / OFF valve 51. The
[0019]
The cylinder resting device 10 is disposed above the valve support 5 and above the shaft 7. And it operates according to rotation of the cam shaft 61 of the cam 60 via the rocker arm 70. In the present embodiment, the cam shaft 61 is provided on the cylinder head 1 side.
As shown in FIG. 2, the cylinder resting device 10 is brought into contact with the valve bridge 11 that operates the intake valves 4 and 4 and the rocker arm 70 according to the rotation of the cam shaft 61, and the inside of the valve bridge 11 and the shaft 7. And an inner piston 20 which is slidably inserted in the vertical direction on the outer side of the inner piston 20.
[0020]
The valve bridge 11 is slidably fitted to the shaft 7 from the upper side of the shaft 7, and a valve pressing portion 12 disposed at a position facing the valve support portion 5 and a piston engaging portion that receives the inner piston 20. 13, a piston guide part 14 for guiding the inner piston 20, a guide lower end part 15 located at the lower end of the guide part 14, a shaft engaging part 16 for receiving the shaft 7, and a shaft guide part 17 for guiding the shaft 7 It has.
[0021]
The inner piston 20 is also fitted into the shaft 7 from above the shaft 7. The inner piston 20 communicates with a piston portion 21 that slides in the vertical direction inside the valve bridge 11 and outside the shaft 7, and a supply oil passage 8 of the shaft 7. The oil chamber 22 is stored, a piston lower end portion 23 located at the lower end of the piston portion 21, and an inner spring 24 interposed between the piston lower end portion 23 and the guide lower end portion 15. Piston upper end provided with switching hydraulic passages 26, 26 communicating with the oil chamber 22 through the passage 25, and two switching valves (switching means) 30 to which hydraulic oil in the switching hydraulic passages 26, 26 is supplied 27 and a piston tip 28 provided with an overpressure valve (pressure releasing means) 40 for releasing the hydraulic oil in the oil chamber 22.
[0022]
The electronic control unit (ECU) 50 determines whether the intake valves 4 and 4 are to be operated or stopped based on the operating conditions of the engine, and outputs this determination result to the ON / OFF valve 51. The ON / OFF valve 51 is opened when the intake valves 4 and 4 are operated, and is closed when the intake valves 4 and 4 are deactivated to open and close the supply oil passage 9.
[0023]
As shown in FIG. 3, the switching valve 30 provided in the inner piston 20 is protruded and subtracted from the pressure receiving portion 31 toward the outside of the cylinder resting device 10, facing the switching hydraulic passage 26. When projecting, it contacts the upper side of the valve bridge 11 and engages with the valve bridge 11 to press the valve bridge 11 downward, a stopper portion 33 positioned around the bridge pressing portion 32, and a piston. The lid 34 is screwed into the upper end 27 and closes the storage portion 37 of the switching valve 30, and the valve spring 36 is interposed between the lid 34 and the pressure receiving portion 31.
[0024]
As shown in FIG. 5A, when hydraulic oil is being supplied, the area where the hydraulic pressure of the hydraulic oil from the switching hydraulic passage 26 acts on the pressure receiving portion 31 increases, and the pressure receiving portion 31 It is strongly pushed outward of the cylinder resting device 10. Therefore, when the pressure receiving portion 31 resists the load of the valve spring 36, the bridge pressing portion 32 protrudes from the protruding port 35 to the outside of the cylinder resting device 10. Thus, the movement of the inner piston 20 is transmitted to the valve bridge 11, and the valve bridge 11 moves downward together with the inner piston 20 to operate the intake valves 4 and 4.
[0025]
On the other hand, as shown in FIG. 5B, when the supply of hydraulic oil is released, there is no hydraulic oil pressure in the switching hydraulic passage 26 that pushes the pressure receiving portion 31. The area where the hydraulic pressure acts on the pressure receiving portion 31 is reduced. Therefore, when the pressure receiving portion 31 follows the load of the valve spring 36, the bridge pressing portion 32 is drawn inside the cylinder resting device 10. As a result, the movement of the inner piston 20 is not transmitted to the valve bridge 11, and only the inner piston 20 moves downward, and the intake valves 4 and 4 are deactivated.
[0026]
As with the switching valve 30, the overpressure valve 40 provided on the inner piston 20 includes a valve body 41 that is screwed to the piston tip 28 and a valve body 41, as shown in FIG. 4. A pressure relief hydraulic passage 42 that communicates with the switching hydraulic passage 26, a valve chamber 44 that communicates with the pressure relief hydraulic passage 42, a ball valve body 45 that contacts the valve seat 43 to open and close the valve chamber 44, and a valve A lid portion 46 that is screwed above the main body portion 41 to close the valve chamber 44, a lubricating oil passage 47 that communicates with the valve chamber 44 within the lid portion 46, and between the lid portion 46 and the ball valve body 45. And a valve spring 48 interposed therebetween.
[0027]
When the pressure of the hydraulic oil in the oil chamber 22 becomes high, the ball valve body 45 separates from the valve seat 43 against the load of the valve spring 48, and the hydraulic oil is discharged from the pressure relief hydraulic passage 42, Via the valve chamber 44 and the lubricating oil passage 47, the oil is discharged out of the cylinder resting device 10 so as to lubricate between the rocker arm 70 and the valve bridge 11. On the other hand, when the pressure in the oil chamber 22 returns to a predetermined value, the ball valve body 45 contacts the valve seat 43 according to the load of the valve spring 48.
[0028]
Next, the operation of the valve suspension apparatus of the present invention will be described.
FIG. 5 is a diagram for explaining a valve operation in the cylinder resting device 10. In the figure, for the purpose of explaining the movement amounts of the inner piston 20 and the valve bridge 11, the cylinder resting device 10 is divided into two parts with its central axis (indicated by a one-dot chain line) interposed therebetween. In other words, the left figure shows the stationary state, while the right figure shows the lifted state.
[0029]
As shown in the figure, when the ECU 50 determines that it is not necessary to perform the cylinder resting operation, the ON / OFF valve 51 is opened, and the supply oil passage 9 and the supply oil passage 8 are provided in the oil chamber 22. The hydraulic fluid from the engine side is supplied through.
When the pressure in the oil chamber 22 increases, the pressure receiving portion 31 of the switching valve 30 overcomes the load of the valve spring 36 and the bridge pressing portion 32 jumps out of the cylinder resting device 10. In this case, the displacement transmitted from the rocker arm 70 to the inner piston 20 side is transmitted to the piston portion 21 and also to the valve bridge 11 side.
[0030]
That is, when the inner piston 20 moves downward by the lift amount L, the bridge pressing portion 32 engaged with the valve bridge 11 also moves downward, and the bridge pressing portion 32 points the valve bridge 11 downward. Press. The valve bridge 11 is also moved downward by the lift amount L to operate (lift) the intake valves 4 and 4.
[0031]
Further, since the pressure of the hydraulic oil in the oil chamber 22 can increase excessively as the piston portion 21 slides, when the pressure in the oil chamber 22 becomes higher than necessary, the overpressure valve 40 is turned off. The pressure is adjusted via.
On the other hand, FIG. 6 is a diagram illustrating the valve resting time in the cylinder resting device 10. As in FIG. 5, the figure on the left side shows the stationary state, while the figure on the right side shows the lifted state.
[0032]
The idle cylinder operation is carried out when the ECU 50 determines, for example, that the exhaust gas temperature should be raised based on the engine speed, the fuel injection amount, the cooling water temperature at the time of startup, the boost pressure, and the like. As shown in the figure, when it is determined by the ECU 50 that it is necessary to perform the cylinder resting operation, the ON / OFF valve 51 is closed and the oil chamber 22 is provided with the supply oil passage 9 and the supply oil passage 8. The hydraulic fluid from the engine side is not supplied.
[0033]
When the pressure in the oil chamber 22 is low, the bridge pressing portion 32 of the switching valve 30 is retracted toward the inside of the cylinder resting device 10. In this case, the displacement transmitted from the rocker arm 70 to the inner piston 20 side is transmitted to the piston portion 21 but not to the valve bridge 11 side.
That is, when the inner piston 20 in this case moves downward by the lift amount L, the bridge pressing portion 32 also moves downward, but the bridge pressing portion 32 does not engage with the valve bridge 11 and the valve bridge 11 is moved downward. The lift amount L of the inner piston 20 is canceled inside the valve bridge 11 because it is not pressed toward the inner side. That is, only the inner piston 20 slides with respect to the valve bridge 11 and the shaft 7. Then, the valve bridge 11 does not move downward, and the intake valves 4 and 4 are paused and stopped.
[0034]
The lift amount L of the inner piston 20 is transmitted to the inner spring 24, but the valve bridge 11 does not move depending on the load of this spring.
As described above, in the present invention, the inner piston 20 is provided inside the valve bridge 11, the oil chamber 22 communicating with the supply oil passage 8 of the shaft 7 is provided inside the inner piston 20, and the intake valve 4, 4 is provided with two switching valves 30 that operate according to the pressure of the supply oil passage 8, and the valve bridge 11 is activated and stopped according to the operation of the switching valve 30, and the rotation of the camshaft 61 is sucked under specific conditions. Do not communicate to valves 4 and 4. In other words, in the present invention, the cylinder resting operation can be performed only by newly providing the change in the configuration of the valve bridge and the configuration of the oil passage for the hydraulic oil, so a complicated variable valve system mechanism is not required, A simple, low-cost and highly reliable idle cylinder mechanism can be easily attached to existing engines.
[0035]
The description of one embodiment of the present invention is finished above, but the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, although the OHC (Over Head Camshaft) type is described in the above embodiment, the present invention is not limited to this embodiment. For example, the camshaft is provided on the crankcase side, and the push An OHV (Over Head Valve) type with a rod may be used, and in this case as well, a simple, low-cost, and highly reliable resting mechanism can be easily attached to the existing engine as described above. And has the effect.
[0036]
Further, the valve deactivation device of the present invention can be applied to the exhaust valve side as well as the intake valve side, and more than two switching valves are provided on the inner piston according to the load of the inner spring. It is good.
[0037]
【The invention's effect】
As can be understood from the above description, according to the valve suspension apparatus of the first aspect of the present invention, an oil passage is not provided on the valve bridge side requiring rigidity, and the oil passage is located inside the valve bridge. Since the inner piston is provided with switching means for operating and stopping the valve, the cylinder resting mechanism can be simplified, space can be saved, and compactness can be achieved.
[0038]
Further, since the switching means transmits the movement of the inner piston to the valve bridge by engaging with the valve bridge only during normal valve operation, the durability can be improved.
In addition, the valve suspension mechanism with reduced cost and improved reliability can be installed in the existing large diesel engine. If the suspension operation is performed at low load, fuel efficiency is improved and exhaust temperature is increased. Can achieve early activation of the exhaust gas aftertreatment device.
[0039]
According to the second aspect of the present invention, by using a plurality of engaging members as the switching means, the engagement and release of the switching means can be made highly reliable and reliable.
Furthermore, according to the third aspect of the present invention, the pressure in the inner piston is appropriately adjusted, and the operation and pause of the valve by the switching means can be performed reliably. Moreover, the oil discharged by depressurization can be used for lubrication around the valve bridge.
[Brief description of the drawings]
FIG. 1 is a partial configuration diagram of an engine to which a valve stop device for a diesel engine according to an embodiment of the present invention is applied.
FIG. 2 is a cross-sectional view of the valve suspension apparatus of FIG.
3 is an enlarged cross-sectional view of a main part of the valve operating / suspending device of FIG. 2;
4 is an enlarged cross-sectional view of a main part of the valve suspension apparatus of FIG.
5 is a view for explaining a valve operation time in the valve operating / pausing device of FIG. 1; FIG.
6 is a diagram for explaining when the valve is stopped in the valve operating / pausing device of FIG. 1; FIG.
[Explanation of symbols]
1 Cylinder Head 4 Valve 7 Shaft 8 Supply Oil Path 10 Resting Device 11 Valve Bridge 20 Inner Piston 22 Oil Chamber 30 Switching Valve (Switching Means)
32 Bridge pressing part 40 Over pressure valve (pressure release means)
50 Electronic control unit (ECU)
61 Cam shaft

Claims (3)

A cylinder head having a valve for opening and closing the cylinder of the internal combustion engine;
A shaft provided in the cylinder head and provided with a supply oil passage for supplying hydraulic oil from a hydraulic source therein;
A valve bridge that is slidably fitted to the shaft and opens and closes the valve;
The oil chamber is slidably fitted between the outer side of the shaft and the inner side of the valve bridge, and has an oil chamber that communicates with the supply oil passage and stores the hydraulic oil therein. An inner piston that is displaced in response to rotation;
When the hydraulic oil is supplied according to the operating conditions of the engine, the inner piston is engaged with the valve bridge to transmit the movement of the inner piston to the valve bridge to operate the valve. On the other hand, when the supply of the hydraulic oil is released, only the inner piston is slid without being engaged with the valve bridge, and the operation of the valve is suspended without transmitting the movement of the inner piston to the valve bridge. Switching means for causing
Depressurizing means for depressurizing the hydraulic oil in the oil chamber;
A valve suspension apparatus for an internal combustion engine, comprising: 2. The valve operating / suspending device for an internal combustion engine according to claim 1, wherein the switching means includes a plurality of engaging members projecting and retracting when the hydraulic oil is supplied and released. 2. The valve stop device for an internal combustion engine according to claim 1, wherein the depressurizing means is provided at a tip portion of the inner piston facing a position where the shaft is disposed.

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