Sliding Cam System for Engine Shutdown Vibration Control
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Solution Overview
Problem
Existing methods for shutting down internal combustion engines fail to effectively reduce vibrations and noise during the shutdown process, leading to increased wear and tear on the engine and associated systems.
Innovation Solution
A method and device utilizing a sliding cam system that actuates the first exhaust valve to open or hold open during the compression and exhaust strokes, allowing for engine braking mode, which reduces engine vibrations and noise by controlling the cam system's operation to switch between normal and engine braking modes, thereby minimizing the need for additional valve actuation systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the exhaust valve is closed during compression and exhaust strokes during shutdown, then the engine compression is maintained, but engine vibrations and noise increase
Solution Approach 1:
The patent applies a sliding cam system that dynamically adjusts the exhaust valve actuation during shutdown. The cam carrier can slide axially to switch between a first cam profile (for normal operation with closed exhaust valve during compression) and a second cam profile (for shutdown with open exhaust valve during compression). This dynamic switching allows the system to adapt the valve timing to reduce vibrations and noise during shutdown while maintaining reliable compression during normal operation.
2Ease of operation
If a separate mechanism is used to actuate the exhaust valve during shutdown, then precise control is achieved, but device complexity increases
Solution Approach 1:
The patent integrates the shutdown valve actuation function into the existing sliding cam system that is already used for engine braking. The same cam carrier and sliding mechanism that provide variable valve timing for engine braking also control the exhaust valve during shutdown by switching between different cam profiles. This multi-functional approach eliminates the need for a separate actuation mechanism, reducing device complexity while maintaining precise control over the exhaust valve timing during shutdown.
Data Source
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AI summary
The invention relates to a method for shutting down an internal combustion engine. The method includes initiating a shutdown process. The method also includes reducing vibration of the internal combustion engine during the shutdown process by switching the actuation of a first exhaust valve (20) of the internal combustion engine by means of a sliding cam system (11) to open or keep open during the compression and exhaust strokes. Alternatively or additionally, the method includes switching to an engine braking mode in which a first exhaust valve (20) of the internal combustion engine is initially kept closed during the compression and/or exhaust strokes to compress air and is opened before reaching top dead center of a piston movement to decompress the compressed air.