Engine braking apparatus and method using single valve and bridge of valve

Abstract

The invention discloses an engine braking device (engine retarder) and an engine braking method for using a single valve and a valve bridge. A driving mechanism of the device comprises a braking hydraulic system integrated in an exhaust valve system as well as a braking bearing system and a brake valve actuator which are integrated in an exhaust valve actuator of an engine. The braking hydraulic system comprises a braking piston arranged in the valve bridge. The device also comprises a control mechanism used to control the piston to move between the non-operating position and the operating position. At the non-operating position, the braking piston retracts for braking the normal separation of the driving mechanism and the engine; at the operating position, the braking piston extends out for braking the driving mechanism to open one of two exhaust valves to produce the braking operation of the engine. The braking device uses a simple and reliable reset mechanism, reduces or even eliminates asymmetrical load produced by the braking of the single valve, does not increase the height and the weight of the engine, reduces elements and the complexity, reduces manufacturing cost, and improves the reliability of a system.

Description

technical field [0001] This invention relates to internal combustion engine braking, and more particularly to an apparatus and method for switching the 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 fuel, opening the exhaust valve at or near the end of the engine piston's compression stroke, allowing the compressed gas (usually air) to be released, and the energy absorbed by the engine to compress the gas during the compression stroke, It cannot be returned to the engine piston during the subsequent expansion or "power" 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 combustion engines, especially compression ignition engines, also known a...

AI Technical Summary

Problems solved by technology

If resetting occurs too quickly, the brake valve lift is lost too much (lower valve lift and early valve closing), reducing braking performance

If the reset happens too late, the brake valve will not be able to close before the main valve action begins, causing an asymmetrical load

Therefore, the rocker integrated brake of the '730 patent may not work properly at high engine speeds because the reset time and height are very small and the load or pressure on the reset valve is very high

[0019] 2. Deflated engine braking

[0024] 1. The previous braking system caused an asymmetric load on the air valve or valve bridge;

[0025] 2. The previous braking system increased the height and weight of the engine;

[0026] 3. The previous braking system was too complicated, so that the manufacturing precision was increased and the cost was too expensive; and

[0027] 4. The previous braking system was unreliable and only worked at certain engine speeds

Images