Axially Displaceable Cam Element Groups for Variable Valve Lift
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Solution Overview
Problem
Existing motor vehicle valve train adjustment devices lack variability and efficiency in activating valves across different engine configurations, particularly in four-cylinder in-line and six-cylinder in-line engines, due to limited axial displacement and independent switching capabilities of cam elements.
Innovation Solution
The device incorporates axially displaceable cam elements grouped for staggered switching, with actuator devices and a control unit allowing independent operation of cam element groups to achieve variable valve lift and timing, enabling efficient activation of valves in four-cylinder and six-cylinder engines by coupling cam elements through actuator devices and controlling their switching positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If cam elements are arranged in an axially displaceable manner, then valve train variability is improved, but device complexity increases
Solution Approach 1:
The camshaft is segmented into multiple independently displaceable cam element groups (first, second, third cam element groups), each capable of axial displacement relative to the camshaft. This segmentation allows each group to be controlled independently, providing valve train variability for different engine configurations without requiring complete redesign of the entire camshaft system.
Solution Approach 2:
The cam elements are designed with axial displacement capability, transitioning from a static camshaft to a dynamic system where cam elements can move along the axial direction. This dynamic configuration enables the valve train to adapt to different operating conditions and engine types while maintaining a unified camshaft structure.
2Adaptability or versatility
If cam element groups are made switchable independently, then adaptability is improved, but control complexity increases
Solution Approach 1:
The camshaft is divided into distinct cam element groups (first, second, third groups) that can be switched independently. Each group can be displaced axially to engage different cam tracks, allowing independent control of valve timing and lift for different cylinder configurations without affecting other groups.
Solution Approach 2:
The same camshaft structure with multiple displaceable cam element groups serves multiple functions: it can configure valves for four-cylinder in-line engines, six-cylinder in-line engines, or V-engine configurations by independently positioning different cam element groups. This multi-functionality reduces the need for separate camshafts for different engine types.
3Adaptability or versatility
If cam elements are axially displaceable, then valve lift variability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The camshaft is segmented into discrete cam element groups that can be axially displaced to selected positions. This segmentation allows for controlled positioning at specific intervals rather than continuous adjustment, reducing manufacturing precision requirements while still achieving the necessary valve lift variability for different engine configurations.
Data Source
AI summary
A device for adjusting a motor vehicle valve train includes at least one camshaft with at least four cam elements arranged in an axially displaceable manner. In each case two of the cam elements that are adjacently situated are formed as a cam element group to be switched together.