Reciprocating-piston internal combustion engine with engine brake and additional opening of an exhaust valve

1. A four-stroke internal combustion engine comprising a crankcase and at least one cylinder that is arranged in the crankcase and in which a working piston is guided by a crankshaft, at least one cylinder head closes the cylinder and includes intake and exhaust channels that are controlled by at least one intake valve and at least one exhaust valve that are each loaded with a closing spring and the at least one intake valve and the at least one exhaust valve are activated by transmission elements driven by a camshaft, and a brake control device by which pressure is built up in an exhaust system in the exhaust channels, and an opening of the at least one exhaust valve is performed, a hydraulic valve clearance compensation element is installed in at least one of the transmission elements between the camshaft and the at least one intake valve and the at least one exhaust valve, wherein the compensation element has at least one piston, a cylinder housing part interacting with the at least one piston, a return spring installed there-between, and a check valve, a locking device is provided that is activated and that limits movement of the at least one piston relative to the cylinder housing part and of the cylinder housing part relative to an outer housing connected to one of the transmission elements at least in one direction of motion, and the at least one piston is supported on a stop body that is connected to the outer housing or the transmission element.

2. Internal combustion engine according to claim 1 , wherein the locking device has a stop that limits adjustment movement of the hydraulic valve clearance compensation element.

3. Internal combustion engine according to claim 2 , wherein activation and deactivation of the locking device is performed by pressurized fluid and a spring force.

4. Internal combustion engine according to claim 1 , wherein the locking device has a clamping sleeve that is arranged between the cylinder housing part and the outer housing or the transmission element, the clamping sleeve forms a stop with the outer housing or the transmission element, and the clamping sleeve is fixed relative to the cylinder housing part.

5. Internal combustion engine according to claim 1 , wherein the locking device has a clamping sleeve that is arranged between the stop body and the outer housing or the transmission element, the clamping sleeve forms a stop with the cylinder housing part, and the clamping sleeve is fixed relative to the stop body.

6. Internal combustion engine according to claim 4 , wherein the stop has a spring ring that is arranged in a recess of the clamping sleeve or the cylinder housing part and is in active connection with a support surface on the outer housing, or on the transmission element, or a support surface on the clamping sleeve.

7. Internal combustion engine according to claim 4 , wherein a clamping sleeve spring is installed that is constructed as a compression spring and is supported on one side on the clamping sleeve and on the other side on the stop body, or outer housing, or on the transmission element.

8. Internal combustion engine according to claim 4 , wherein at least one clamping body is supported in the cylinder housing part or in the stop body so that the at least one clamping body can move, wherein the at least one clamping body is loaded on one side by a clamping body spring and is loaded on the other side by pressurized fluid, and the clamping sleeve is fixed by the clamping body relative to the stop body or the cylinder housing part.

9. Internal combustion engine according to claim 8 , wherein teeth or grooves that are complementary to each other are provided on the at least one clamping body on a surface facing the clamping sleeve and on the clamping sleeve on a surface facing the at least one clamping body.

10. Internal combustion engine according to claim 8 , wherein at least two clamping bodies are provided that are supported against each other by a clamping body spring and the clamping sleeve has, in a wall in a region of the clamping body, openings that are connected controllably to a pressurized fluid source.

11. Internal combustion engine according to claim 8 , wherein the clamping sleeve is locked in rotation relative to the cylinder housing part.

12. Internal combustion engine according to claim 11 , wherein the rotational locking is realized by an alignment pin that is inserted into the clamping sleeve and that is in active connection with a longitudinal groove in the cylinder housing part.

13. Internal combustion engine according to claim 8 , wherein facing surfaces of at least two clamping bodies are in active connection with an adjustment pin that is arranged in the cylinder housing part.

14. Internal combustion engine according to claim 8 , wherein at least two clamping bodies are provided that are loaded against each other by a tension spring and, in a region of facing surfaces of the at least two clamping bodies, a borehole is provided in the stop body that is connected controllably to a pressurized fluid source.

15. Internal combustion engine according to claim 14 , wherein the tension spring is constructed as a tubular spring that is arranged in grooves in surfaces of the at least two clamping bodies facing the clamping sleeve.

16. Internal combustion engine according to claim 14 , wherein a spring ring is inserted in the stop body between the facing surfaces of the at least two clamping bodies.