Internal combustion engine

Abstract

An internal combustion engine may include at least one cylinder, a first outlet valve and a second outlet valve for directing exhaust gas out from a combustion chamber of the at least one cylinder. The first outlet valve may include a first valve opening and a first valve body where the first valve opening is adjustable between a closed position and an open position. The second outlet valve may include a second valve opening and a second valve body where the second valve body is adjustable between a closed position and an open position. An adjusting lever may adjust one or both of the first valve body and the second valve body between the open position and the closed position.

Claims

1. An internal combustion engine, comprising: at least one cylinder including a combustion chamber; a first outlet valve and a second outlet valve for directing exhaust gas out from the combustion chamber of the at least one cylinder; the first outlet valve including a first valve opening and a first valve body, wherein the first valve body is adjustable between a closed position where the first valve body closes the first valve opening, and an open position where the first valve body frees the first valve opening for flowing through by the exhaust gas; the second outlet valve including a second valve opening and a second valve body, wherein the second valve body is adjustable between a closed position where the second valve body closes the second valve opening, and an open position where the second valve body frees the second valve opening for flowing through by the exhaust gas; a shared, rotatable adjusting lever, wherein the first valve body and the second valve body via the shared, rotatable adjusting lever are respectively adjustable simultaneously between the open position and the closed position of the first outlet valve and the second outlet valve; and wherein the first valve body and the second valve body are constructed such that after the first valve body is adjusted by a predetermined adjustment travel away from the closed position of the first outlet valve, the second valve body still closes the second valve opening.

2. The internal combustion engine according to claim 1, wherein the predetermined adjustment travel is between 0.1 mm and 0.5 mm.

3. The internal combustion engine according to claim 2, wherein the second valve body in the closed position of the first outlet valve projects further into the second valve opening than the first valve body into the first valve opening.

4. The internal combustion engine according to claim 1, wherein the second valve body in the closed position of the first outlet valve projects deeper into the second valve opening than the first valve body into the first valve opening.

5. The internal combustion engine according to claim 4, wherein the second valve body is arranged at a distance to the second valve opening that is smaller than that of the first valve body to the first valve opening when the first outlet valve and the second outlet valve are in the open position.

6. The internal combustion engine according to claim 1, wherein in the open position of the first outlet valve and the second outlet valve, the second valve body is arranged at a smaller distance to the second valve opening than the first valve body to the first valve opening.

7. The internal combustion engine according to claim 6, wherein a distance difference of the first valve body and the second valve body to the first valve opening and the second valve opening in the open position of the first valve outlet and the second valve outlet, respectively, corresponds substantially to the predetermined adjustment travel.

8. The internal combustion engine according to claim 7, wherein the predetermined adjustment travel ranges from 0.1 mm to 0.5 mm.

9. The internal combustion engine according to claim 1, wherein the first valve body has a first body height and the second valve body has a second body height; and wherein the second body height is greater than the first body height.

10. The internal combustion engine according to claim 9, wherein the first body height is substantially identical to the second body height, and wherein the first valve body and the second valve body are arranged axially offset to one another by the predetermined adjustment travel on the shared, rotatable adjusting lever.

11. The internal combustion engine according to claim 1, wherein the first valve body and the second valve body respectively have a geometry substantially of a cylinder with a first cylinder height and a second cylinder height, respectively, and wherein the second cylinder height is greater than the first cylinder height.

12. The internal combustion engine according to claim 11, wherein a difference of the first cylinder height and the second cylinder height corresponds substantially to an amount of the predetermined adjustment travel.

13. The internal combustion engine according to claim 1, wherein the shared, rotatable adjusting lever includes a first lever arm and a second lever arm, and wherein the first valve body and the second valve body are arranged on the first lever arm, and a cam follower base body is arranged on the second lever arm.

14. The internal combustion engine according to claim 1, further comprising a valve train for driving the shared, rotatable adjusting lever, the valve train including: a camshaft and a cam follower drivingly connected with the shared, rotatable adjusting lever; a first cam mounted in a torque-proof manner on the camshaft and a second cam arranged in a torque-proof manner and axially adjacent to the first cam; and wherein the cam follower is axially adjustable between a first position where the cam follower is drivingly connected with the first cam, and a second position where the cam follower is drivingly connected with the second cam.

15. The internal combustion engine according to claim 14, wherein the cam follower includes a cam follower base body rigidly connected with the shared, rotatable adjusting lever, and a cam follower roller mounted rotatably on the cam follower base body, wherein the cam follower roller in the first position of the cam follower is drivingly connected with the first cam, and in the second position of the cam follower the cam follower roller is drivingly connected with the second cam.

16. The internal combustion engine according to claim 15, wherein a rotation axis of the shared, rotatable adjusting lever runs parallel to at least one of a rotation axis of the cam follower roller and a rotation axis of the camshaft.

17. The internal combustion engine according to claim 15, wherein the shared, rotatable adjusting lever includes a first lever arm and a second lever arm, and wherein the first valve body and the second valve body are arranged on the first lever arm, and the cam follower base body is arranged on the second lever arm.

18. The internal combustion engine according to claim 14, wherein a rotation axis of the shared, rotatable adjusting lever runs parallel to a rotation axis of the camshaft.

19. The internal combustion engine according to claim 1, wherein the shared, rotatable adjusting lever includes a lever arm structured and arranged to simultaneously adjust the first valve body and the second valve body.

20. An internal combustion engine, comprising: at least one cylinder defining a combustion chamber; a first outlet valve and a second outlet valve for directing exhaust gas out from the combustion chamber of the at least one cylinder; the first outlet valve including a first valve opening and a first valve body, wherein the first valve body is adjustable between a closed position where the first valve body closes the first valve opening, and an open position where the first valve body frees the first valve opening for flowing through by the exhaust gas; the second outlet valve including a second valve opening and a second valve body, wherein the second valve body is adjustable between a closed position where the second valve body closes the second valve opening, and an open position where the second valve body frees the second valve opening for flowing through by the exhaust gas; a shared, rotatable adjusting lever including a lever arm structured and arranged to simultaneously adjust the first valve body and the second valve body respectively between the open position and the closed position of the first outlet valve and the second outlet valve; wherein the first valve body and the second valve body are configured such that after the first valve body is adjusted by a predetermined adjustment travel away from the closed position of the first outlet valve, the second valve opening is closed by the second valve body; wherein the second valve body in the closed position of the first outlet valve projects further into the second valve opening than the first valve body projects into the first valve opening; and wherein the second valve body is arranged at a distance to the second valve opening that is smaller than that of the first valve body to the first valve opening in the open position of the first outlet valve and the second outlet valve.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) There are shown, respectively diagrammatically:

(2) FIG. 1 the structure of an internal combustion engine according to the invention,

(3) FIG. 2 the internal combustion engine of FIG. 1 in a top view,

(4) FIGS. 3 to 6 the two outlet valves in different positions between their respective open and closed position,

(5) FIGS. 7 and 8 the structure and mode of operation of a valve train of the internal combustion engine for actuating the outlet valves.

DETAILED DESCRIPTION

(6) FIG. 1 illustrates in a rough diagrammatic illustration the structure of an internal combustion engine 100 according to the invention. The internal combustion engine 100 comprises a cylinder 102, indicated roughly diagrammatically in FIG. 2. The internal combustion engine can have further cylinders, not illustrated in further detail in the figures, which can be constructed in an analogous manner to the cylinders illustrated with the aid of the figures. A combustion chamber 103 is present in the cylinder 102.

(7) According to FIG. 1, the internal combustion engine 100 furthermore comprises a first outlet valve 104a and a second outlet valve 104b for directing exhaust gas out from the combustion chamber 103 of the cylinder 102. The first outlet valve 104a comprises a first valve opening 105a and a first valve body 106a. The first valve body 106a is adjustable between a closed position, in which it closes the first valve opening 105a, and an open position, in which it frees the first valve opening 105a for flowing through by the exhaust gas. The second outlet valve 104b comprises a second valve opening 105b and a second valve body 106b. The second valve body 6b is adjustable between a closed position, in which it closes the second valve opening 105b, and an open position, in which it frees the valve opening 105b for flowing through by the exhaust gas.

(8) Further technical details of the internal combustion engine 100, such as for example inlet valves for directing fresh or respectively charge air into the cylinder 102, and a piston arranged adjustably in the combustion chamber 103, are known to the relevant specialist in the art and are not the focus of the present invention and therefore, for reasons of clarity, are not illustrated in FIG. 1.

(9) As the illustration of FIG. 1 directly shows, the internal combustion engine 100 has an adjusting lever 101 which is rotatable about a rotation axis D. By means of the adjusting lever 101, the two valve bodies 106a, 106b can be adjusted simultaneously between their respective open position and their respective closed position. An axial direction a is defined here by the rotation axis D of the adjusting lever 101.

(10) FIG. 2 shows the internal combustion engine 100 of FIG. 1 in a top view along the axial direction a. As evidenced by FIG. 2, the two valve bodies 106a, 106b can have respectively substantially the geometric shape of a cylinder 107a, 107b.

(11) The two valve bodies 106a, 106b of the internal combustion engine 100 are constructed such that after the adjusting of the first valve body 106a by a predetermined adjustment travel s away from its closed position, the second valve body 106b still closes the second valve opening 105b. This characteristic of the two valve bodies 106a, 106b, which is essential to the invention, is explained below with the aid of FIGS. 3 to 6:

(12) FIG. 3 shows in a highly simplified, diagrammatic illustration the two outlet valves 104a, 104b in their respective closed position, in which the two valve openings 105a, 105b are closed by the respectively associated valve bodies 106a, 106b. The two valve bodies 106a, 106b, as indicated in FIGS. 3 to 6, can have respectively substantially the geometric shape of a cylinder 107a, 107b. The valve bodies 106a, 106b can have, in a known manner, a valve shaft, which towards the cylinder 102 of the internal combustion engine 100 continues into a valve plate with an increased diameter compared to the valve shaft. For reasons of clarity, such a structural embodiment of the valve bodies 106a, 106b is not illustrated in FIGS. 3 to 6.

(13) Through a movement of the adjusting lever 101 (the latter is likewise not shown in FIGS. 3 to 6 for reasons of clarity), the two valve bodies 105a, 105b are moved away from the valve openings 106a, 106b (cf. arrow 108 in FIG. 3). The movement of the first valve body 106a brings about an immediate freeing of the first valve opening 106, whereas the second valve opening 105b still remains closed by the second valve body 106b.

(14) FIG. 4 shows a position of the two outlet valves 104a, 104b, in which as a consequence of this movement, the first valve body 106a of the first outlet valve 104a was moved by the predetermined adjustment travel away from the closed position shown in FIG. 3. The second valve body 106b of the second outlet valve 104b was also adjusted by means of the control lever 101 by the same predetermined adjustment travel s, but in the position shown in FIG. 4just as in the position according to FIG. 3still closes the second valve opening 105b. This predetermined adjustment travel s can be, for example, between 0.1 mm and 0.5 mm. However, other values are also conceivable, according to application-specific requirements.

(15) In the position of the two valve bodies 106a, 106b according to FIG. 4, exhaust gas A can therefore exit from the combustion chamber 103 through the first outlet valve 104a (cf. arrow 109 in FIG. 4), but not through the second outlet valve 104b. Only a further moving of the control lever 101 and a movement, accompanying this, of the two valve bodies 106a, 106b beyond the predetermined adjustment travel also brings about a freeing of the second valve opening 105b by the second valve body 106b, so that exhaust gas A can now exit from the combustion chamber 103 both through the first outlet valve 104a and also through the second outlet valve 104b (arrows 110). The two valve bodies 106a, 106b can be adjusted into their open position by further adjusting of the control lever 101, in which they are adjusted to a maximum extent away from their closed position. The diagrammatic illustration of FIG. 6 shows the open position of the two outlet valves 104a, 104b.

(16) In the open position of the two outlet valves 104a, 104b, a distance d.sub.2 of the second valve body 106b to the second valve opening 105b is less than a distance d.sub.1 of the first valve body 16a to the first valve opening 105a.

(17) The distance difference d=d.sub.1d.sub.2 of the two valve bodies 106a, 106b in the open position to the respective valve opening 105a, 105b corresponds substantially to the predetermined adjustment travel s, therefore d=s.

(18) As the illustration of FIG. 4 shows, to realize the distance difference d a second cylinder height h.sub.2 of the second cylindrical valve body 106b can be greater than a first cylinder height h.sub.1 of the first cylindrical valve body 106a. In this case, the difference of the two cylinder heights h.sub.1, h.sub.2 corresponds substantially to the amount of the predetermined adjustment travel s. The same principle can be followed to realize the distance difference d, when the two valve bodies 106a, 106b do not have a cylindrical shape, but rather a different suitable geometric shape with a first and a second body height k1, k2, which is measured along a direction which runs perpendicularly to an opening plane of the respective valve opening 105a, 105b. In this more general case, the difference of the two body heights k.sub.1, k.sub.2 corresponds substantially to the amount of the predetermined adjustment travel s.

(19) In an alternative variant, which is not shown in FIGS. 3 to 6, the two valve bodies 106a, 106b can have respectively substantially the geometry of a cylinder with identical cylinder heights h.sub.1, h.sub.2, therefore h.sub.1=h.sub.2. In order to ensure that also in this case, after the adjusting of the first valve body 106a by the predetermined adjustment travel s away from its closed position, the second valve body 106b is still situated in its closed position, the two cylindrical valve bodies 106a, 106b with the same cylinder heights h.sub.1, h.sub.2 are arranged, axially offset to one another by the predetermined adjustment travel s, on the adjusting lever 101.

(20) The offset opening of the two outlet valves 104a, 104b or respectively of the two valve openings 105a, 105b, which is essential to the invention, can also be realized in a further variant with identically constructed valve bodies 106a, 106b, when the second valve body 106b in the closed position of the first outlet valve 104a projects deeper into the second valve opening 105b than the first valve body 1056a into the first valve opening 105a (not shown in the figures). With a simultaneous movement of the two valve bodies 106a, 106b, the second valve opening 105b is freed only later than the first valve opening 105a, so that also in this variant the opening of the two outlet valves 104a, 104b takes place offset to one another.

(21) FIGS. 7 and 8 illustrate in diagrammatic illustration an example of a valve train 1 of the internal combustion engine 100 for controlling the adjusting lever 101. The valve train 1 comprises a camshaft 2 and a cam follower 3. A first cam 4a is mounted in a torque-proof manner on the camshaft 2. Axially adjacent to the first cam 4a, a second cam 4b is arranged on the camshaft 2, likewise in a torque-proof manner with respect thereto.

(22) The cam follower 3 adjustable along the axial direction a between a first position, in which it is drivingly connected with the first cam 4a, and a second position, in which it is drivingly connected with the second cam 4b. FIG. 7 shows the cam follower 3 in said first position, FIG. 8 shows the cam follower 3 in its second position. The cam follower 3 can have a cylindrically constructed cam follower base body 5, on the circumferential side of which a hollow-cylindrically constructed cam follower roller 6 is rotatably mounted. The cam follower base body 5 is also known to the relevant specialist in the art under the term roller pin or displacement axis. The drive connection of the two cams 4a, 4b with the cam follower 3 takes place in a known manner via the cam follower roller 6. Here, the rotary movement of the camshaft 2 is converted by means of the cams 4a, 4b into a rotary movement of the adjusting lever 101 about the rotation axis D. The rotary movement of the adjusting lever 101 is, in turn, accompanied by a movement of the outlet valves 104a, 104b between their respective open or respectively closed position.

(23) In the first position of the cam follower 3, shown in FIG. 7, the cam follower roller 6 is coupled with the first cam 4a, in FIG. 2 with the second cam 4b. The cam follower roller 6 controls (not shown) via a suitably constructed mechanical coupling arrangement, in particular in the manner of an actuator, a valve for adjusting between an open and a closed state. Practical technical realization possibilities of such a coupling are not part of the present invention, but are known to the relevant specialist from the prior art in various forms, so that a more detailed explanation in this respect can be dispensed with.

(24) The cam follower 3 of FIG. 7 has a mechanical adjustment arrangement 7, cooperating with the camshaft 2, for the axial adjustment of the cam follower 3 between the first and the second position. The mechanical adjustment arrangement 7 comprises for this a first adjustable mechanical engagement element 8a. The first mechanical engagement element 8a cooperates with a first slide guide 9a, present on the camshaft 2, for the axial adjusting of the cam follower 3 from the first position shown in FIG. 7 into the second position. In an analogous manner, the mechanical adjustment arrangement 7 has an adjustable second mechanical engagement element 8b. The second engagement element 8b cooperates with a second slide guide 9b, present on the camshaft 3, for the axial adjusting of the cam follower 3 from its second into the first position.

(25) The mechanical adjustment arrangement 7 further comprises a first actuator 10a, by means of which the first engagement element 8a is adjustable between a first position, shown in FIG. 7, in which it engages into the first slide guide 9a, and a second position, shown in FIG. 8, in which it does not engage into the first slide guide 9a. The mechanical adjustment arrangement 7 also comprises a second actuator 10b, by means of which the second engagement element 8b is adjustable between a first position, in which it engages into the second slide guide 9b, and a second position, in which it does not engage into said second slide guide 9b.

(26) The first actuator 10a is adjustable between an inactive position and an active position. For this purpose, the two actuators 10a, 10b can be constructed as linearly adjustable, electrically driven actuators. The mechanical adjustment arrangement 7 is realized in this case as an electromechanical adjustment arrangement. In other words, electrically driven actuators 10a, 10b are comprised here by the term mechanical adjustment arrangement 7.

(27) The two actuators 10a, 10b are controllable by a control arrangement 11 of the valve train 1 for adjusting between their active position and their inactive position. This adjustability is realized such that the first actuator 10a in the inactive position is out of contact with the first engagement element 8a. In the course of an adjustment from its inactive position into its active position, the first actuator 10a adjusts the first engagement element 8a through mechanical contact from its second into its first position.

(28) The adjustment of the first engagement element 8a from the first into the second position can preferably be brought about by means of the stroke movement of the cam follower 3, in particular by means of the cam follower base body 5. Here, the cam follower 3 is moved by the stroke movement brought about by the first or second cam 4a, 4b in the direction of the first actuator 10a. When the latter is in its active position, then through the stroke movement of the cam follower 3 and therefore of the first engagement element 8a, this is pressed against the first actuator 10a and is adjusted thereby into its second position.

(29) In this state, the first engagement element 8a engages into the first slide guide 9a, so that the cam follower 3, owing to the rotary movement of the camshaft 2, is moved by means of the first slide guide 9a, arranged thereon, axially from its first into the second position. The second actuator 10b is also adjustable between an inactive position and an active position. This adjustability is realized such that the second actuator 10b in the active position is out of contact with the second engagement element 8b. In the course of an adjusting from its inactive position into its active position, the second actuator 10b adjusts the second engagement element 8b through mechanical contact from its second into its first position.

(30) The adjustment of the second engagement element 8b from the first into the second position is preferably also brought about by means of the stroke movement of the cam follower 3, in particular by means of the cam follower base body 5. Here, the cam follower 3 is moved by the stroke movement brought about by the first or second cam 4a, 4b in the direction of the second actuator 8b. When the latter is in its active position, then through the stroke movement of the cam follower 3 and therefore of the second engagement 8b, this is pressed against the second actuator 10b and is therefore adjusted thereby into its second position.

(31) In this state, the second engagement element 8b engages into the second slide guide 9b, so that the cam follower 3 owing to the rotary movement of the camshaft 2, by means of the second slide guide 9a arranged thereon, is moved axially from its second into the first position.

(32) The first actuator 10a has a linearly adjustable (cf. arrow 15a) first adjustment element 12a. The latter can partially project from a first housing 16a of the first actuator 10a and be arranged linearly adjustably relative thereto. A face side 13a of the first adjustment element 12a, facing the first engagement element 8a, which can be constructed in a pin- or bolt-like manner, presses, on moving of the first engagement element 8a into the first slide guide 9a, against a face side 14a of the first engagement element 8a lying opposite the first adjustment element 12a. The second actuator 10b has a linearly adjustable (cf. arrow 15b) second adjustment element 12b. The latter can partially project from a second housing 16b of the second actuator 10b and be arranged linearly adjustably relative thereto. A face side 13b of the second adjustment element 12b, facing the second engagement element 8b, which can be constructed in a pin- or bolt-like manner, presses, on moving of the second engagement element 8b into the second slide guide 9b, against a face side 14b of the second engagement element 8b lying opposite the second adjustment element 12b.

(33) As the illustration of FIG. 8 shows, the cam follower 3 also has a cam follower fixing arrangement 17 for the detachable fixing of the cam follower 3 in the first or second position. The cam follower fixing arrangement 17 comprises a spring-loaded cam follower fixing element 18. In the first position of the cam follower 3, the cam follower fixing element 18 engages into a first mount 19a provided on the cam follower 3, and in the second position of the cam follower 3 engages into a second mount 19b provided on the cam follower 3. Preferably, the first mount 19a, as illustrated in FIG. 2, is realized as a first circumferential groove 20a, which is arranged on a circumferential side 21 of the cam follower 3. The second mount is realized accordingly as a second circumferential groove 20b arranged axially at a distance on the circumferential side 21.

(34) As FIGS. 7 and 8 clearly demonstrate, the cam follower 3 for the two engagement elements 8a, 8b, preferably for both engagement elements 8a, 8b, has respectively a first or respectively second engagement element fixing arrangement 22a, 22b for the detachable fixing of the first or respectively second engagement element 8a, 8b in the first or second position. As can be seen, the two engagement element fixing arrangements 22a, 22b have respectively a spring-loaded fixing element 23a, 23b, which in the first position of the respective engagement element 8a, 8b is received in a first mount 24a, 24b provided on the respective engagement element 8a, 8b. In the second position of the cam follower, the fixing element 23a, 23b is received in a second mount 25a, 25b provided on the cam follower. The first and the second engagement element 8a, 8b have respectively a base body 29a, 29b constructed in a bolt-like or pin-like manner. On a circumferential side of the base body 29a, 29b the first mount 24a, 24b is formed as a first circumferential groove 27a, 27b, and the second mount 25a, 25b is formed as a second circumferential groove 28a, 28b arranged axially at a distance on the circumferential side.

(35) In the following, with the aid of the illustration of FIGS. 7 and 8, an adjusting of the cam follower 3 from the first into the second position is explained. In the scenario of FIG. 1, the cam follower 3 is situated in the first position, in which its cam follower roller 6 is drivingly connected with the first cam 4a.

(36) If an adjustment of the cam follower 3 is to take place from its first into its second axial position, then the first engagement element 8a of the mechanical adjustment arrangement 7, as shown in FIG. 7, is brought into engagement with the first slide guide 9a. This takes place by means of the first electric actuator 10a.

(37) The first actuator 10a, as already explained, is adjustable between an inactive position shown in FIG. 7 and an active positionindicated by dashed lines in FIG. 1. In the inactive position, the first actuator 10a is mechanically out of contact with the first engagement element 8a. In the course of an adjusting from its inactive position into its active position, the first actuator 10a adjusts the first engagement element 8a through mechanical contact from its second into its first position. In the first position, the first engagement element 8a engages into the first slide guide 9a (cf. FIG. 7), so that the cam follower 3 through the rotary movement of the camshaft 2 by means of the first slide guide 9a is moved axially from its first into its second position, which is illustrated in FIG. 2. After the bringing into engagement of the first engagement element 8a with the first slide guide 9a, the first actuator 10a can be moved back by the control arrangement 11 into its inactive position again.

(38) The first slide guide 9ajust as the second slide guide 9bcan have a ramp structure, not shown in the figures, such that the first engagement element 8a is brought out of engagement with the first slide guide, as soon as the cam follower 3 has reached the second axial position. In this second position, the second cam 4b is in driving connection with the cam follower roller 6. The adjusting of the cam follower 3 from the second position back into the first position can take place by means of the second actuator 10b, of the second engagement element 8b and of the second slide guide 9b in an analogous manner to the transition, explained previously, from the first into the second position of the cam follower 3.