RU2680899C2 - Apparatus and method for actuating at least one exhaust valve of a valve-controlled internal combustion engine for a vehicle and such a vehicle - Google Patents

Abstract

FIELD: machine building.SUBSTANCE: apparatus for actuating an exhaust valve is used in valve-controlled internal combustion engines for motor vehicles. In the force flow between camshaft (2) and at least one operating member (7) acting on the exhaust valve there is at least one means by means of which the exhaust valve can be held in a non-closed intermediate position. Means is formed by an integrated in valve gear step switch mechanism (9) which can be switched in a pulse-like actuation between a regular valve actuator and at least one intermediate position. Step switch mechanism (9) has guide sleeve (10) with longitudinal grooves of different depths, force-transmitting star (11) entering the longitudinal grooves and interacting with star (11) via a torque transmitting device, actuator (12) non-rotatably installed in guide sleeve (10). By means of the step switch mechanism (9), in addition to the basic position in which the exhaust valve is closed, several intermediate positions that can be pulse-like adjustable by means of an electronic feed-back control device can be activated. Step switch mechanism (9), in pulse-like actuation, can be pulse-like switchable between regular valve actuation and at least one intermediate position. Method for actuating at least one exhaust valve of a valve-controlled internal combustion engine for a vehicle and a vehicle are disclosed.EFFECT: technical result is providing the possibility of precise valve distribution both in the regular engine mode and in the engine braking mode.17 cl, 4 dwg

Description

The present invention relates to a device for actuating at least one exhaust valve of an internal combustion engine with valve distribution for automobiles according to the preamble of claim 1. The invention further relates to a method for actuating at least one exhaust valve of an internal combustion engine with valve distribution for automobiles according to the preamble of claim 11.

For example, from US 2010/319657 A1 it is known to increase the braking effect of an internal combustion engine in forced idle mode by decompressing an overpressure by means of a shut-off valve in the exhaust path (EVB or, respectively, Exhaust valve brake, exhaust brake valve), while at least one exhaust valve of each cylinder of the internal combustion engine in braking mode is kept open in an intermediate position. In the valve mechanism of an internal combustion engine, this is done by means of a hydraulically actuated assembly of a cylinder with a piston in a power flow between the camshaft cam and the load transferring element to the exhaust valve to actuate or, respectively, the beam.

The objective of the invention is to offer a predominantly mechanically functioning standard device of this kind, which structurally simple means provides the ability to accurately valve distribution in normal engine mode and in engine braking mode. Another object of the invention is to provide a method that enables accurate valve distribution in both normal engine mode and engine braking mode.

This problem can be solved using the features of the independent claims. Preferably, improvements and embodiments of the invention are the subject of the dependent claims.

According to claim 1, a device is provided for actuating at least one exhaust valve of an internal combustion engine with valve distribution for automobiles, in which, preferably, in a power flow between the camshaft and at least one actuating element acting on the exhaust valve, is provided at least one means by which said at least one exhaust valve, in particular during engine braking with exhaust gas support, can be held in a non-closed intermediate position. In accordance with the invention, it is proposed that said at least one means for setting an intermediate position of said at least one exhaust valve be formed by a step-by-step switching mechanism integrated in the valve mechanism, in particular a step-by-step switching mechanism operating on the principle of being actuated by pressing a ballpoint pen, and then this step-by-step switching mechanism during actuation can be pulsedly switched from the usual actuation of valves by at least one intermediate position, and vice versa.

This kind of structure with structurally simple means enables accurate valve distribution both in the normal engine mode and in the engine braking mode, which, moreover, is also resistant to mechanical damage and little susceptible to malfunctions and at the same time has a long service life. Moreover, the term "pulsed" is understood to be spaced apart in time and, thus, step-by-step actuation, in which the step-by-step switching mechanism falls or, accordingly, "jumps" to various positions or positions. This actuation itself can be initiated in a variety of ways, which is explained in more detail below.

Particularly preferably, the step-by-step switching mechanism has a guide sleeve provided with longitudinal grooves of various depths, engaged in longitudinal grooves, transmitting the force to the sprocket and interacting with the sprocket by means of a torque transmission device, preferably made in the form of a helical gear, mounted rotatably in the guide sleeve executive agency. The dimensions of these longitudinal grooves of different depths are preferably designed so that in one switching position of the stepping switching mechanism, the normal actuation of the valves with a closing exhaust valve is activated, and in the next switching position, an intermediate position in which the exhaust valve is not fully closed, and in Combined with exhaust gas support creates a targeted decompression effect. At a very general point of view, in connection with the switching process, it is preferable to ensure that when switching the rays or, accordingly, the sprocket teeth, respectively, engage in a groove of the same depth. For example, if there are two types of grooves of different depths, preferably each groove of the first depth is located next to the less deep second groove, so that when pulsed, a simple jump occurs or, accordingly, switches between the two switching positions. The same applies to the case of more than two types of grooves of different depths, when it is ensured that when switching the rays or, accordingly, the teeth of the sprocket respectively mesh into the groove of the same depth. If necessary, the implementation of multi-stage braking is also possible.

In order to achieve exact values of the switching time and short switching paths, the actuating element can be pre-axially tensioned by means of a preload element, such as, for example, a spring, with respect to the sprocket end surface of the sprocket.

In one of the preferred embodiments of the invention, the step-by-step switching mechanism can be integrated into the cam follower, preferably the guide sleeve runs onto the camshaft cam and the force-transmitting sprocket directly or indirectly transmits the movement to the valve. But this system can also be built in kinematic inversion.

In this case, the step-by-step switching mechanism can be inserted into the existing valve mechanisms almost without structural changes and forms a structure resistant to mechanical damage, accurately transmitting forces for actuating the valves. In this case, it is preferable that the sprocket can transmit movement to the beam integrated in the valve mechanism.

To switch the step-by-step switching mechanism according to the control technique, an impulse load can be transmitted to the actuator, preferably mechanically and / or hydraulically and / or electromagnetically, by means of a control device; if necessary, this can be done by modifying an existing engine control device in accordance with the specific parameters of the engine and / or movement.

In one of the preferred improvements of the invention, for an internal combustion engine in which two exhaust valves of each cylinder are actuated together by means of a valve bridge, it is proposed that a fixed counter-support with a variable stop position be provided on one side of the valve bridge and that the stepping switching mechanism is located in the power flow between the counter support and the valve bridge. Moreover, while maintaining the design of the valve mechanism having a valve bridge, structurally optimally possible reliable control of both the normal engine mode and the intermediate position of only one of the two exhaust valves.

In this case, the step-by-step switching mechanism can preferably be integrated into the counter support, the guide sleeve being fixedly mounted and the sprocket forming a variable stop for the valve bridge. In particular, with this arrangement, a simplified adjustment of the step-by-step switching mechanism is possible, since it is not included in the valve mechanism undergoing dynamic loading. If necessary, by means of a step-by-step switching mechanism, along with the main position (closed exhaust valve), it is possible to include several intermediate positions of the exhaust valve, which can be pulsed by means of an electronic control device with feedback control. At the same time, at a low additional cost, an additional degree of freedom would be created in controlling the decompression effect of the exhaust valve or, accordingly, exhaust valves.

In addition, in an internal combustion engine having several cylinders, respectively, at least one exhaust valve in the engine braking mode is kept open by means of a step-by-step switching mechanism, while, in particular, by a discrete setting of step-by-step switching mechanisms, it is possible to purposefully control the engine braking mode its action. So, only one cylinder, several cylinders, or all cylinders of an internal combustion engine, for example, in engine braking mode, could be included in the decompression action.

Finally, by means of a step-by-step switching mechanism, said at least one exhaust valve can be kept open for a short time when starting the internal combustion engine to facilitate starting, for example, at low outside temperatures.

The advantages provided by the implementation of the proposed invention by the method and / or by the proposed invention by a car, in particular a truck, by analogy correspond to the above advantages.

By way of example only, two exemplary embodiments of the invention are explained in more detail below.

The schematic drawing shows:

FIG. 1 is only a partially depicted valve mechanism for an exhaust valve of an internal combustion engine with a valve distribution for automobiles, having a camshaft, which drives a rocker by means of a pusher, and having a hydraulically switchable step-by-step switching mechanism integrated in the pusher to set the intermediate position of the exhaust valve;

FIG. 2 shows, in an exploded view, the essential details of the step-by-step switching mechanism in accordance with FIG. 1, having a guide sleeve, a force transmitting sprocket, and a switching stepping switching mechanism, a hydraulically actuated actuator;

FIG. 3 is only a partially illustrated valve mechanism for actuating two exhaust valves of each cylinder of an internal combustion engine by means of a valve bridge, wherein the step-by-step switching mechanism in accordance with FIG. 2 is integrated in a fixed counter support and is included in the main position, which corresponds to the normal engine mode; and

FIG. 4 - valve mechanism in accordance with FIG. 3, while the stepping switching mechanism is switched to the intermediate position of the exhaust valve corresponding to the engine braking mode.

In FIG. 1 is a partial cross-sectional view of a simplified illustration of a cylinder head 1 of a turbocharged diesel internal combustion engine for automobiles, in particular trucks, having a camshaft 2, which drives both the intake valves and at least one exhaust valve by means of cams 3 each cylinder. If there is no image in the rest, the valve mechanism can be performed in a known manner.

The actuation of the exhaust valves (not shown here) is carried out respectively by means of cams 3, which, through the rollers 4, act on pushers 5 mounted axially displaceable in the wall 1a of the cylinder head 1. Pushers 5 load the rollers 6 of the rocker arm 7, which are supported to rotate on a fixed axis 8 in the cylinder head 1 and which, in a known manner, actuate the exhaust valves.

In each of the pushers 5, a step-by-step switching mechanism 9 is integrated, which, being in the power flow of the valve mechanism, can switch from the main position corresponding to the usual actuation of the valves, to the position in which the given or given exhaust valve (s) is held or held in intermediate position. In the intermediate position, the exhaust valves are not closed, but form a flow gap to create a decompression action in the engine braking mode.

In FIG. 2 in conjunction with FIG. 1 schematically shows the design of a stepping switching mechanism 9 or, accordingly, its switching function. The essential structural elements are the guide sleeve 10, the force transmitting sprocket 11 and the actuating element 12 switching.

The guide sleeve 10 here forms, as an example, a part identical to the push rod 5 and has a roller 4 mounted on its lower side and running onto the cams 3 (cf. FIG. 1). In the guide sleeve 10, on the one side between and on the other side through the radially protruding parallel axis of the rib 10a, axially oriented grooves 10b, 10c are made, which alternately have a shallower depth 10b and a greater depth 10c. For example, here the groove 10b of the first, shallower depth always follows the groove 10c of the second, greater depth compared to it.

Then, depending on the switching position of the step-by-step switching mechanism 9, the radially outwardly directed beams, teeth or ribs 11b of the sprocket 11 are inserted into these grooves 10b or 10c, while the number of ribs 11b of the sprocket 11 is equal to the number of grooves 10b and the number of slots 10c in the guide sleeve 10.

When the ribs 11b of the sprocket 11 mesh into the deeper grooves 10c of the guide sleeve 10, the exhaust valves can be closed in the usual way. When the ribs 11b of the sprocket 11 mesh into the shallower grooves 10b, by means of the sprocket 11 and the rocker 7, the exhaust valves are held in a predetermined (open) intermediate position in which they create a decompression action under the engine braking mode.

Switching the positions of the sprocket 11 is carried out by means of an axially displaced axially displaced guide sleeve 10, but without the possibility of rotation of the actuator 12, which on the front side has a helical crown 12a that is adjacent to the corresponding helical crown 11a of the sprocket 11.

When the actuator 12 is displaced in the axial direction, then through the interacting helical gears 12a, 11a, it first creates a torque acting on the sprocket 11, and at the same time pushes it out of the grooves (10b or 10c) until it engages in the circumferential direction by the ribs 10a. Then the sprocket 11 can rotate relative to the guide sleeve 10 until the ribs 11b of the sprocket 11 can slide into respectively adjacent grooves (10b or 10c).

This occurs, as can be seen from FIG. 1 by means of a cylinder block 1b formed in the cylinder head wall 1a of the inlet channel 1b, which flows into the pressure chamber 10d inside the guide sleeve 10 and by means of which an impulse load can be transferred to the sprocket 11 in the direction of the sprocket 11.

Moreover, the compression spring 13 supported on the guide sleeve 10 supported on the wall 1a, as an example of a pre-tensioning element in a pressure-free state, supports the connection without a gap in the power flow from the cam 2 through the guide sleeve 10 and the sprocket 11 to the beam 7. In channel 1b, not shown, by means of a hydraulic control valve and an electronic engine control device adjusting this valve, pulsed fluid can be injected under pressure to switch I have a 9 step switch.

In FIG. 3 and 4, in separate sections, the well-known valve mechanism for actuating two exhaust valves 14 of each cylinder of an internal combustion engine is shown (only one exhaust valve 14 is shown and without valve spring), to which the load is transmitted by acting on the valve rods of two exhaust valves 14 bridge 15. Functionally identical parts are provided with the same reference signs.

The power flow in the valve mechanism proceeds similarly to FIG. 1 through a leading camshaft 2, equipped with cams 3, which act on one common beam 7, the free lever of which in the middle transmits the movement to the valve bridge and thus actuates both exhaust valves 14.

In the cylinder head 1, a counter support 16 is fixedly fixed, which extends beyond the valve bridge 15 in the region of the exhaust valve 14, which has the ability to control with installation in an intermediate position.

The counter support 16 is integrated as described in FIG. 2 is a step-by-step switching mechanism 9, into which liquid under pressure can be introduced to switch through the inlet channel 17 located here above.

The step switching mechanism 9 has, in turn, a guide sleeve 10 fixedly screwed into the counter support 16 there, an asterisk 11 facing the valve bridge 15 and an actuator 12 mounted in the guide sleeve 10, which is adjacent to the pressure chamber 10d.

The design of the stepping gear 9 is similar to that of FIG. 2 with the difference that the structural elements are located in the kinematic inversion and, in a broad sense, are also included in the power flow of the valve mechanism.

When arranged in accordance with FIG. 3 and 4, the sprocket 11 pointing downward in the engine braking mode forms a stop acting on the valve bridge 15, which, being supported on the counter support 16, holds the illustrated exhaust valve 14 in an intermediate position (Fig. 4), which creates a decompression action, while in in the normal mode of the engine with gas supply (Fig. 3) it is retracted, idle.

The pulse switching of the stepping switching mechanism 9 is carried out hydraulically, as described above, and therefore is not described in detail. The positioning of the stepping switching mechanism 9 can, as shown, be carried out by purposefully screwing the guide sleeve 10 into the counter support 16 and fixing by means of the lock nut 19.

Switching the step-by-step switching mechanism 9 from the usual engine mode with gas supply to the engine braking mode with the corresponding intermediate position of the exhaust valves 14 can be carried out hydraulically, for example, when the control device signal indicates the engine braking mode, and vice versa. If necessary, the switching can be performed not hydraulically, but electromagnetic, by embedding the corresponding electromagnetic actuator.

The switching control for setting the intermediate position of the exhaust valve 14 can also be carried out when starting the internal combustion engine and, if necessary, at low outside temperatures, to facilitate the start of its operation (higher starting speed).

If necessary, the step-by-step switching mechanism 9 can also be designed so that several intermediate positions of the exhaust valves 14 can be pulsed for variable control of the decompression action. In this case, the guide sleeve 10 or, accordingly, the number of grooves 10b, 10c in the guide sleeve 10 should be a multiple of the number of ribs 11b of the sprocket 11, in order to provide other intermediate positions along with the main position (engine mode).

The electronic switching control of the step switching mechanism 9 may preferably be a feedback control that displays the current switching state of the step switching mechanism 9. This can be implemented, for example, by means of a sensor system integrated into the step switching mechanism 9.

The step switching mechanisms 9 of the entire valve mechanism of the internal combustion engine can, if necessary, be discretely configured, so that in the engine braking mode only one cylinder or several cylinders or, accordingly, all cylinders can switch to the decompression action applied to the exhaust gas back-up.

Reference List

1 cylinder head

1a Wall

1b inlet channel

2 camshaft

3 cam

4 Roller

5 Pusher

6 Roller

7 Rocker

8 axis

9 Stepping gear

10 Guide sleeve

10a Ribs

10b, 10c grooves

10d pressure chamber

11 Asterisk

11a helical crown

11b Ribs

12 Executive Body

12a helical crown

13 spring

14 Exhaust valve

15 valve bridge

16 Counter

17 inlet channel

18 Connecting screw

19 Locknut

Claims (20)

1. Device for actuating at least one exhaust valve of an internal combustion engine with valve distribution for automobiles, in which at least one means is provided in the power flow between the camshaft and at least one actuator acting on the exhaust valve whereby said at least one exhaust valve can be held in a non-closed intermediate position, wherein said at least one means It is indicated by a step-by-step switching mechanism integrated into the valve mechanism (9), which, when pulsed, can switch between normal valve actuation and at least one intermediate position, characterized in that the step-by-step switching mechanism (9) has a guide sleeve (10) with longitudinal grooves (10b, 10c) of various depths, included in the longitudinal grooves (10b, 10c) of the force-transmitting sprocket (11) and interacting with the sprocket (11) by means of a torque transmission device the moment installed without the possibility of rotation in the guide sleeve (10) the actuator (12), and / or by means of a step-by-step switching mechanism (9), along with the main position in which the exhaust valve is closed, it is possible to include several intermediate positions, which can be pulsed via an electronic control device with feedback control, and / or in the case of pulse actuation, the step-by-step switching mechanism (9) can be pulsed between normal actuation of the valves and at least one intermediate position. 2. The device according to claim 1, characterized in that the step-by-step switching mechanism (9) has said guide sleeve (10) with longitudinal grooves (10b, 10c) of different depths arranged and alternating, and / or a device for transmitting torque moment has a helical crown (12a, 11a). 3. The device according to claim 1, characterized in that the actuator (12) by means of a pre-tensioning element, in particular by means of a spring (13), is pre-axially stretched relative to the end surface (11a) of the sprocket (11) provided with a gear rim. 4. The device according to one of claims 1 to 3, characterized in that the step-by-step switching mechanism (9) is integrated into the plunger (5) of the valve mechanism. 5. The device according to one of claims 1 to 3, characterized in that the guide sleeve (10) runs on the cam (3) of the camshaft (2) and the sprocket (11) directly or indirectly transmits the movement to the exhaust valve (14). 6. The device according to one of claims 1 to 3, characterized in that the sprocket (11) transmits the movement to the rocker arm (7) integrated in the valve mechanism. 7. The device according to one of claims 1 to 3, characterized in that, for switching the step-by-step switching mechanism (9) to the actuator (12), the load is transmitted impulse mechanically and / or hydraulically and / or electromagnetically via a control device. 8. The device according to one of claims 1 to 3, characterized in that two exhaust valves (14) of each cylinder of the internal combustion engine are actuated together by means of one valve bridge (15), while on one side of the valve bridge (15) is provided a fixed counter-support (16) with a variable stop position, while the step-by-step switching mechanism (9) is located in the power flow between the counter-support (16) and the valve bridge (15). 9. The device according to claim 8, characterized in that the step-by-step switching mechanism (9) is integrated into the counter support (16), while it is preferably provided that the guide sleeve (10) of the step-by-step switching mechanism (9) is stationary and the sprocket (11) the stepping switching mechanism (9) formed a variable emphasis for the valve bridge (15). 10. The device according to claim 1 or 2, characterized in that the said at least one exhaust valve (14) in the engine braking mode with exhaust gas back-up can be held in an unclosed intermediate position. 11. The method of actuating at least one exhaust valve of an internal combustion engine with valve distribution for cars when using a device for actuating at least one exhaust valve of an internal combustion engine with valve distribution according to one of claims 1 to 10, wherein preferably in the power flow between the camshaft and at least one actuating element acting on the exhaust valve, at least one means is provided by wherein said at least one exhaust valve can be held in an unclosed intermediate position, characterized in that said at least one means is formed by a step-by-step switching mechanism integrated into the valve mechanism (9), which, when pulsed, switch between normal actuation valves and at least one intermediate position. 12. The method according to claim 11, characterized in that the internal combustion engine having several cylinders, respectively, at least one exhaust valve (14) is kept open by a stepping switching mechanism (9) in the engine braking mode and using, in particular discrete, settings of stepping switching mechanisms (9), purposeful control of the engine braking mode is carried out. 13. The method according to claim 11 or 12, characterized in that by means of a step-by-step switching mechanism (9), the exhaust valve (14) is briefly held open when the internal combustion engine is started. 14. The method according to claim 11 or 12, characterized in that at least one means is provided by which said at least one exhaust valve can be held in a non-closed intermediate position during engine braking with exhaust gas back-up. 15. The method according to claim 11 or 12, characterized in that the said step-by-step switching mechanism (9) when pulsed actuation pulse switch between the usual actuation of the valves and at least one intermediate position. 16. A vehicle comprising a device for actuating at least one exhaust valve of an internal combustion engine with valve distribution according to claim 1 or 2. 17. The car according to clause 16, characterized in that it is a truck.

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