Integrated engine braking device with mechanical chaining and method for changing movement of engine air valve

Abstract

The invention discloses an integrated engine braking device (engine retarder) with mechanical chaining and a method for changing the movement of an engine air valve. A driving mechanism of the device is partially or completely integrated in one or more components of a vent valve train of the engine and can move between a non-operating position and an operating position. On the non-operating position, the driving mechanism retracts and is separated from the normal operation of the engine; and on the operating position, the driving mechanism extends out to form mechanical chaining, and the vent valve of the engine is opened to generate the operation of braking the engine. On the top of the valve lift curve, the resetting mechanism of the device leads the driving mechanism to retract from an extending position so that the valve lift curve can be reset to be small. The invention also provides a method for changing the movement of the engine air valve, comprising the steps of operating and resetting the braking device. The device adopts the mechanical chaining, has simple structure and reliable running, avoids the problem of great compression of hydraulic chaining and reduces the braking response time.

Description

technical field [0001] The present invention relates to internal combustion engine braking, in particular to an engine braking device (engine retarder) integrated in an engine valve train and a method for converting an internal combustion engine from normal operation to braking operation. Background technique [0002] It is well known to use an internal combustion engine as a means of braking, simply by temporarily converting the engine to a compressor. This conversion can be achieved by cutting off the fuel, opening the exhaust valve at or near the end of the engine piston compression stroke, allowing the compressed gas (air during braking) to be released, and the energy absorbed by the engine during the compression stroke. It cannot be returned to the engine piston during the subsequent expansion stroke, but is dissipated through the engine's exhaust and cooling system. The end result is efficient engine braking. [0003] Engine braking is necessary for internal combusti...

AI Technical Summary

Problems solved by technology

[0031] 1) The previous braking system could only be installed on one specific type of engine;

[0032] 2) The moment of inertia of the previous braking system was too large, and the reaction (on and off) time was too long;

[0033] 3) The previous braking system was driven by hydraulic pressure, which was too flexible, resulting in reduced engine braking performance and increased load;

[0034] 4) The previous braking system caused an asymmetric load on the valve or valve bridge;

[0035] 5) The previous braking system had too many components and was too complicated to work properly at high engine speeds;

[0036] 6) The previous brake system did not have an easy way to set the slack of the engine brake valve;

[0037] 7) The previous braking system was unreliable and too sensitive to external disturbances;

[0038] 8) Previous braking system affects normal engine performance (efficiency and exhaust emissions)

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