DE102017221527A1 - Valve Piston System of an internal combustion engine and internal combustion engine - Google Patents

Abstract

Valve piston system (20) of a cylinder of an internal combustion engine, with an up and down movably guided piston (26), with at least one inlet side gas exchange valve (21) and at least one outlet side gas exchange valve (22), wherein the piston (26) an end facing the gas exchange valves (21, 22) a central piston recess (27) and the gas exchange valves (21, 22) facing, lateral valve pockets (28) which pass into the central piston recess (27), and wherein the respective valve pocket (28 ) such a plate portion-like or funnel portion-like is formed, that the respective gas exchange valve (21, 22) facing surface (29) thereof relative to a vertical (30) to the axial direction of the piston (26) or a vertical (30) to the axial direction (25) of a valve body (24) of the respective gas exchange valve (21, 22) is inclined.

Description

The invention relates to a valve-piston system of an internal combustion engine and an internal combustion engine.

Internal combustion engines typically have several cylinders. Each cylinder of an internal combustion engine has a piston which is guided in a cylinder liner of the respective cylinder movable up and down. In addition, each cylinder of an internal combustion engine has at least one inlet-side gas exchange valve for at least charge air and at least one outlet-side gas exchange valve for exhaust gas. Then, when the internal combustion engine is designed as a gas engine, not only charge air, but also gaseous fuel in the form of a gas-air mixture for combustion is supplied to the respective cylinder via the or each inlet side gas exchange valve. Then, when the internal combustion engine is designed as a diesel engine, each cylinder has at least one injector, via which the fuel can be supplied to the cylinder.

From practice it is known that a piston of a cylinder of an internal combustion engine has a central piston recess on a surface facing the gas exchange valves or on an end facing the gas exchange valves. Furthermore, it is known that the gas exchange valves facing valve pockets are formed at this end of the piston, with such valve pockets, a collision between the piston and valve bodies of the gas exchange valves during operation of the internal combustion engine can be avoided.

Proceeding from this, the present invention has the object to provide a novel valve-piston system of an internal combustion engine and an internal combustion engine with such a valve-piston system.

This object is achieved by a valve-piston system of an internal combustion engine according to claim 1. According to the invention, the respective valve pocket is formed in the manner of a plate section or funnel section, such that a surface thereof facing the respective gas exchange valve is inclined relative to a perpendicular to the axial direction of the piston or perpendicular to the axial direction of a valve body of the respective gas exchange valve. Due to the fact that in the valve-piston system according to the invention, the valve pockets are formed like a plate section or funnel section, the formation of so-called hotspots in the transition region between the valve pockets and the piston recess is avoided. Furthermore, less turbulence occurs during combustion, so that overall the combustion of the fuel can take place more effectively and therefore with higher efficiency.

Preferably, the respective gas exchange valve facing surface of the respective valve pocket is inclined in the direction of the piston recess. This is particularly preferred for reducing or avoiding hotspots and for reducing turbulences.

According to a development, a valve body of the respective gas exchange valve is formed in such a cone-like or frusto-conical section that one of the respective valve pocket facing surface thereof is inclined relative to the perpendicular to the axial direction of the valve body. Preferably, the surface of the respective valve body facing the respective valve pocket is inclined away from the piston recess. Again, this is preferred to avoid hotspots and to reduce turbulence. Furthermore, a safety distance between the valve bodies of the gas exchange valves and the piston is maintained with minimal space.

According to a development of the invention, the respective gas exchange valve facing surface of the respective valve pocket is inclined at a first angle, wherein the respective valve pocket facing surface of the respective valve body is inclined at a second angle. Preferably, the first angle and the second angle are equal, so that the inclined surfaces are parallel to each other. Alternatively, the second angle is greater than the first angle. This embodiment of the invention is preferred for reducing or avoiding hotspots and for reducing turbulence in the combustion chamber of the cylinder while ensuring a safety distance between the valve bodies of the gas exchange valves and the piston with minimal space.

The internal combustion engine according to the invention is defined in claim 10.

Preferred embodiments of the invention will become apparent from the dependent claims and the description below.

• 1 eine Draufsicht auf einen Zylinder einer Brennkraftmaschine;
• 2 einen Ausschnitt aus einem aus der Praxis bekannten Ventil-Kolben-System einer Brennkraftmaschine;
• 3 einen Ausschnitt aus einem erfindungsgemäßen Ventil-Kolben-System einer Brennkraftmaschine.

Embodiments of the invention will be described, without being limited thereto, with reference to the drawings. Showing:

• 1 a plan view of a cylinder of an internal combustion engine;
• 2 a section of a known from practice valve-piston system of an internal combustion engine;
• 3 a section of a valve-piston system according to the invention of an internal combustion engine.

The invention relates to a valve-piston system of an internal combustion engine and an internal combustion engine.

1 shows a highly schematic plan view of a cylinder of an internal combustion engine. The cylinder 10 the 1 has in the embodiment shown several inlet-side gas exchange valves 11 as well as several outlet-side gas exchange valves 12 , So are in 1 two inlet-side gas exchange valves 11 shown over the at least charge air into a combustion chamber of the cylinder 10 can be introduced. In 1 Fuel is injected into the combustion chamber of each cylinder via an injector 13 introduced via the liquid fuel, such as diesel, heavy oil or residual oil, can be injected into the combustion chamber of the respective cylinder. Exhaust gas produced during the combustion of the fuel can be discharged via the outlet-side gas exchange valves 12 be removed from the combustion chamber.

It should be noted at this point that the invention is not limited to use in internal combustion engines in which a liquid fuel, such as diesel, heavy oil or residual oil, is burned. Rather, the invention can also be used in gas engines, in which a gaseous fuel is burned, wherein in such gas engines, a mixture of charge air and gaseous fuel into the combustion chamber of the cylinder via the inlet side gas exchange valves 11 is introduced. Furthermore, the invention can be used in dual-fuel engines.

2 shows a partial cross section through a cylinder 10 an internal combustion engine, wherein the in 2 correspond to details of the practice or the prior art. So shows 2 from the gas exchange valve shown 11 or. 12 a valve body 14 moving in the direction of its axial direction 15 is movable up and down in operation to the respective gas exchange valve 11 or. 12 to open or close. Further shows 2 a valve piston 16 which is guided in a cylinder sleeve, not shown, movable up and down, in the direction of an axial direction of the piston 10 that are typically parallel to the axial direction 15 of the valve body 14 of the respective gas exchange valve 11 . 12 runs.

As 2 can be taken, it is already known from practice that the piston 16 at one of the gas exchange valves 11 . 12 facing the end of a central piston recess 17 having. Further shows 2 at this end of the piston 16 a valve bag 18 that the respective valve body 14 of the respective gas exchange valve 11 or. 12 facing, wherein over the respective valve pocket 18 During operation, a minimum distance between the piston 16 and the valve body 14 of the respective gas exchange valve 11 . 12 is provided to in operation a collision between the piston 16 of the respective cylinder and the respective valve body 14 of the respective gas exchange valve 11 or. 12 of the respective cylinder 10 to avoid.

3 shows a section of a valve-piston system according to the invention 20 a cylinder 23 an internal combustion engine, namely in the region of a valve body 24 an inlet-side or outlet-side gas exchange valve 21 or. 22 and a piston 26 , In operation, the valve body 24 in the direction of its axial direction 25 movable to the respective gas exchange valve 21 or. 22 to open or close. The piston 26 of the cylinder 23 is in the direction of its axial direction (not shown) in a cylinder liner, not shown 23 guided up and down movable, wherein the axial direction of the piston 26 typically parallel to the axial direction 25 of the respective valve body 24 of the respective gas exchange valve 21 or. 22 runs.

At one of the gas exchange valves 21 . 22 facing the end, the piston 26 a piston recess 27 on, the middle of the gas exchange valves 21 . 22 facing the end of the piston 26 is trained.

Furthermore, the piston has 26 of the respective cylinder 23 at this the gas exchange valves 21 . 22 facing end valve pockets 28 on that with the gas exchange valves 21 . 22 interact. These valve bags 28 go into the middle piston recess 27 over.

For the purposes of the present invention, the respective valve pocket 28 formed like a plate portion or funnel portion, namely such that one of the respective gas exchange valve 21 . 22 namely, the valve body 24 of the respective gas exchange valve 21 . 22 , facing surface 29 the respective valve bag 28 opposite a vertical 30 to the axial direction of the piston 26 or to the axial direction 25 of the valve body 24 of the respective gas exchange valve 21 . 22 is inclined, in the direction of the piston recess 27 of the piston 26 with a first angle α.

With this configuration, the formation of so-called hotspots, in particular in the area of the valve pockets 28 , in particular in the region of a transitional edge 31 between the respective valve bag 28 and the piston recess 27 , further avoids turbulence, which is the combustion of the fuel in the combustion chamber of the cylinder 23 affect. The valve pockets 28 go harmoniously into the piston recess 27 over.

The valve body 24 is so cone-like or frustoconical on a piston 26 formed facing the end that one of the respective valve pocket 28 facing surface 32 opposite a vertical 33 to the axial direction 25 of the respective valve body 24 with a second angle β is inclined, in such a way that the respective valve pocket 28 facing surface 32 of the respective valve body 24 from the piston 26 or from the piston recess 27 or from the respective valve pocket 28 is inclined away.

As stated, that is the respective gas exchange valve or the respective valve body 24 of the respective gas exchange valve 21 . 22 facing surface 29 the respective valve bag 28 inclined at the first angle α, wherein the respective valve pocket 28 facing surface 32 of the respective valve body 24 of the respective gas exchange valve 21 . 22 with the second angle β is inclined. Preferably, the first angle α and the second angle β the same size, so that the inclined surfaces 29 . 32 parallel to each other.

Alternatively, it is also possible that the first angle α and the second angle β are different in size, so then the inclined surfaces 29 . 32 not parallel to each other, in particular in this case the first angle α smaller than the second angle β or the second angle β is larger than the first angle α then there are virtual extensions of the inclined surfaces 29 . 32 in the area of the piston 26 , in particular in the area of the piston recess 27 , to cut.

The two angles α . β be at most 45 °, preferably at most 40 °, more preferably at most 35 °.

With the invention, the formation of undesirable hotspots or areas with too high temperatures, in particular in the transition region between the valve pockets 28 and the piston recess 27 be avoided. Furthermore, turbulences of a fuel substance to be combusted are reduced in the combustion chamber of the respective cylinder, as a result of which combustion can take place with greater efficiency. A collision between the valve bodies 24 the gas exchange valves 21 . 22 and the valve piston 26 is avoided.

The invention can be used both in diesel internal combustion engines and in Otto internal combustion engines, both in 2-stroke and in 4-stroke internal combustion engines. In this case, both a liquid fuel, such as diesel, heavy oil or residual oil, or a gaseous fuel, such as natural gas, are burned in the cylinders of the respective internal combustion engine.

LIST OF REFERENCE NUMBERS

10

cylinder

11

inlet-side gas exchange valve

12

outlet gas exchange valve

13

injector

14

valve body

15

axially

16

piston

17

piston bowl

18

valve pocket

20

Valve-piston system

21

inlet-side gas exchange valve

22

outlet gas exchange valve

23

cylinder

24

valve body

25

axially

26

piston

27

piston bowl

28

valve pocket

29

surface

30

vertical

31

edge

32

surface

33

vertical

Claims (10)

Valve piston system (20) of a cylinder of an internal combustion engine, with an up and down movably guided piston (26), with at least one inlet side gas exchange valve (21) and at least one outlet side gas exchange valve (22), wherein the piston (26) a the gas exchange valves (21, 22) facing the end of a central piston recess (27) and the gas exchange valves (21, 22) facing, lateral valve pockets (28) which pass into the central piston recess (27), characterized in that the respective valve pocket (28) is formed plate-like or funnel portion like that a respective gas exchange valve (21, 22) facing surface (29 ) thereof with respect to a vertical (30) to the axial direction of the piston (26) or a vertical (30) to the axial direction (25) of a valve body (24) of the respective gas exchange valve (21, 22) is inclined. Valve-piston system after Claim 1 , characterized in that the respective gas exchange valve (21, 22) facing surface (29) of the respective valve pocket (28) in the direction of the piston recess (27) is inclined. Valve-piston system after Claim 1 or 2 , characterized in that a valve body (24) of the respective gas exchange valve (21, 22) is formed cone-like or frusto-conical portion such that one of the respective valve pocket (28) facing surface (32) thereof opposite a vertical (33) to the axial direction (25) of the valve body (24) is inclined. Valve-piston system after Claim 3 , characterized in that the respective valve pocket (28) facing surface (32) of the respective valve body (24) of the piston recess (27) is inclined away. Valve-piston system after Claim 3 or 4 , characterized in that the respective gas exchange valve (21, 22) facing surface (29) of the respective valve pocket (28) at a first angle (α) is inclined, and that the respective valve pocket (28) facing surface (32) of the respective valve body (24) with a second angle (β) is inclined. Valve-piston system after Claim 5 , characterized in that the first angle (α) and the second angle (β) are equal, so that the inclined surfaces (29, 32) parallel to each other. Valve-piston system after Claim 5 , characterized in that the first angle (α) and the second angle (β) are different in size, so that the inclined surfaces (29, 32) are not parallel to each other. Valve-piston system after Claim 7 , characterized in that the second angle (β) is greater than the first angle (α). Valve-piston system after Claim 7 , characterized in that the first angle (α) and the second angle (β) amount to a maximum of 45 °. Internal combustion engine with at least one cylinder, wherein the or each cylinder is a valve-piston system according to one of Claims 1 to 9 having.

Images