Variable Valve Train Rocker Arm with Hydraulic Locking
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Solution Overview
Problem
Conventional variable valve trains for internal combustion engines require significant space and are complex to assemble, with existing designs often necessitating external spring stops and independent storage of rocker arms, which limits pre-assembly and increases assembly costs and space requirements.
Innovation Solution
A compact variable valve train design featuring a camshaft with offset cams and a rocker arm system, including a roller lever and hydraulic locking device, allowing for pre-assembly and easy installation without altering surrounding components, with the hydraulic locking device enabling selective cam engagement to adjust valve lift and timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional variable valve trains use external spring stops and independent storage of rocker arms, then the valve train can achieve variable valve operation, but the assembly complexity increases and pre-assembly is limited
Solution Approach 1:
The patent combines the spring stop function directly into the rocker arm structure by integrating a recess for receiving the return spring. This merging eliminates the need for separate external spring stops and independent storage mechanisms, thereby reducing assembly complexity while maintaining variable valve operation capability through the selective engagement of different cam profiles.
Solution Approach 2:
The rocker arm is designed with multi-functionality by incorporating both the lever arm for valve actuation and the recess for return spring storage within a single integrated component. This universal design allows the rocker arm to serve multiple functions simultaneously, reducing the number of separate parts needed and simplifying the overall assembly process while enabling variable valve operation.
2Adaptability or versatility
If conventional variable valve trains use multiple independent components, then the valve train can be adjusted, but the installation space required increases
Solution Approach 1:
The patent merges multiple functions into the rocker arm structure, including the lever arm for valve actuation and the recess for return spring storage. This integration reduces the number of separate components and minimizes the overall installation space required while maintaining the adjustability needed for variable valve operation through selective cam engagement.
Solution Approach 2:
The return spring is nested within the recess of the rocker arm structure, allowing the spring to be stored compactly within the existing component geometry. This nesting approach eliminates the need for separate external spring stops and reduces the overall installation space while preserving the adjustability of the valve train system.
3Adaptability or versatility
If conventional variable valve trains require altering surrounding components, then the valve train can be integrated, but the retrofitting complexity increases
Solution Approach 1:
The rocker arm is designed as a universal component that can be retrofitted into existing valve train systems without requiring modifications to surrounding components. The integrated design with built-in return spring recess allows it to function independently while maintaining compatibility with standard camshafts and valve mechanisms, thereby facilitating easy retrofitting while achieving full integration.
Solution Approach 2:
The rocker arm design incorporates self-contained features, including the recess for return spring storage and the lever arm for valve actuation, allowing it to function independently without requiring external spring stops or modifications to surrounding components. This self-service design enables easy retrofitting into existing systems while achieving complete integration and variable valve operation capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design achieves a compact, easy-to-assemble valve train that reduces installation space and assembly costs, allowing for retrofitting existing systems without altering the cylinder head, while enabling variable valve operation with different opening and closing times and lifts.
Implementation Method 1
a switchable hydraulic locking device, by means of which the rocker arm and the roller lever can optionally be locked rigidly with one another
Data Source
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AI summary
The invention relates to a variable valve train for a poppet valve, in particular for a charge exchange valve of an internal combustion engine, which can be periodically moved between a closed and an open position indirectly by means of a cam via a rocker arm. The variable valve train (1) comprises a camshaft (3) having at least one first cam (3) and at least one second cam (4, 5) arranged offset in the longitudinal direction of the camshaft (3), wherein the at least one first cam (3) and the at least one second cam (4, 5) have different cam profiles.The valve train (1) further comprises a rocker arm (10) pivotably mounted about a rocker arm axis (2), which at its camshaft-side end (11) is associated with the at least one first cam (3) via a pressure roller (13) and at its valve-side end (12) is operatively connected to at least one poppet valve, as well as a roller lever (20) which at its camshaft-side end (21) is associated with the at least one second cam (4, 5) and at its other end is pivotably connected to the rocker arm (10) about the rocker arm axis (2). The variable valve train (1) further comprises a switchable hydraulic locking device (30) by which, when the rocker arm (10) and the roller lever (20) are rigidly locked together when engaged or disengaged, and both follow the movement of the at least one second cam (4, 5).