Internal combustion piston engine with an adjustable inflating element

Abstract

An internal combustion piston engine based on a four-stroke process, having a crankcase in which at least one cylinder / piston assembly is arranged, the piston being guided by a connecting rod connected to a crankshaft. At least one cylinder head (1) closes the cylinder, each of whose intake and exhaust channels are controlled by at least one intake valve and at least one exhaust valve (2, 2a). The intake and exhaust valves are actuable by a finger lever or a rocker arm driven by a camshaft (12) through intake and exhaust cams. The finger levers or rocker arms are guided on at least one axle (10). At least one additional cam is provided in the region of the base circle of the outlet cam for an additional opening of the at least one exhaust valve (2, 2a), and a control element is installed between the finger lever or rocker arm and the exhaust valve or valves (2, 2a), which control element can be connected to a pressure oil source and has a variable length, so that the additional cam is active during a compression relief operation and inactive during a pure engine operation. The control element is configured as an inflating element (8) and is operatively connected through a working piston (7), with interposition of a spacer, to a bridge (4) associated to a plurality of exhaust valves (2, 2a), or is operatively connected to a valve stem of an exhaust valve.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of German Patent Application No. 102010011455.3, filed Mar. 15, 2010, which is incorporated herein by reference as if fully set forth.FIELD OF THE INVENTION[0002]An internal combustion piston engine based on a four-stroke process, comprising a crankcase in which at least one cylinder / piston assembly is arranged, the piston being guided by a connecting rod connected to a crankshaft, further comprising at least one cylinder head for closing the cylinder, each of whose intake and exhaust channels are controlled by at least one intake valve and one exhaust valve, said intake and exhaust valves being actuable by a finger lever or a rocker arm driven by a camshaft through intake and exhaust cams, the finger levers or rocker arms being guided on at least one axle, further comprising at least one additional cam in the region of the base circle of the outlet cam for an additional opening of at least one exhaust ...

AI Technical Summary

Benefits of technology

The invention is a piston engine with an improved engine brake system that can be easily and inexpensively realized. The system uses an inflating element connected to the engine's exhaust valves to create a brake through intermittent opening of the valves. The inflating element builds up pressure by itself, so only a low pressure is required as a control oil pressure. The system also allows for easy adjustment of valve lash and can be used for internal gas recirculation or hybridization. The use of ball sockets and a ball head helps avoid undesired surface pressures and ensures safe fixation of the inflating element. The inflating element includes components of a hydraulic valve lash adjusting element and can be used for internal gas recirculation or hybridization. The system is controlled by a control piston that is pressed against a non-return valve by a spring and oil pressure, and can activate the additional cam to open the compression relief device or recirculation device.

Problems solved by technology

A drawback of this configuration is that the oil pressure is used directly for the actuation of the piston, so that a high pressure or a larger piston cross-section is required and strong pressure fluctuations can occur.

Furthermore, the additional valve lash adjusting screw is considered as a drawback because, irrespective of the additional complexity and expense caused by the thread and the like, it constitutes an undesired additional mass.

The required structural complexity for extending and retracting the additional cams is considerably high and cost-intensive and therefore considered as a drawback.

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