Multi-Cylinder Engine Valve System Axial Cam Switching
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Solution Overview
Problem
The existing valve systems for multi-cylinder engines face challenges in reducing the number of components while maintaining the ability to switch cams efficiently during high-speed engine rotation, particularly due to limited timing for operation member projection between adjacent cylinders with discontinuous ignition orders.
Innovation Solution
A valve system with a cam shaft and operation mechanism that includes cam element sections with common base circles and differently shaped nose sections, using both common and individual operation members to move cam elements axially, allowing for efficient switching during high-speed rotation by optimizing the timing and positioning of operation members between adjacent cylinders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single operation member is disposed between adjacent cylinders to reduce component number, then the number of components is reduced, but the period for projecting the operation member decreases during high-speed rotation
Solution Approach 1:
The patent combines multiple operation members into a single integrated operation member that can simultaneously engage with end face cams of multiple cam element sections. This merging reduces the total number of components while maintaining the necessary operational coverage across adjacent cylinders, resolving the contradiction between component reduction and sufficient projection period.
Solution Approach 2:
The operation member is designed to extend in the axial direction to span across multiple cam element sections simultaneously. By utilizing the axial dimension, a single operation member can engage multiple cams that would otherwise require separate operation members, thereby reducing component count while maintaining adequate engagement time during high-speed rotation.
2Adaptability or versatility
If end face cams are provided on both end faces to move cam element section to both sides, then the cam switching capability is improved, but the number of operation members increases
Solution Approach 1:
The single operation member is designed with multi-functionality to serve multiple purposes: it can engage with end face cams on both sides of cam element sections, control cam switching in multiple directions, and operate across adjacent cylinders. This universal design provides full cam switching capability without requiring separate operation members for each function.
Solution Approach 2:
Multiple operation members that would traditionally be required for bidirectional cam switching are merged into a single operation member. This consolidated design maintains the ability to move cam element sections to both sides while reducing the total number of components needed in the system.
3Speed
If operation member projects between opposed end face cams of two cam element sections, then the cam element sections can be separated in axial direction, but the projection period becomes too short during high-speed rotation
Solution Approach 1:
The operation member is designed to engage with the end face cams in advance, before the cam element sections need to be separated. By establishing engagement beforehand and maintaining it throughout the separation process, the system ensures sufficient interaction time even during high-speed rotation, preventing switching failures.
Solution Approach 2:
The operation member maintains continuous engagement with the end face cams throughout the entire cam switching process. This continuous action ensures that the useful function of cam separation is performed without interruption or timing gaps, thereby maintaining reliable operation during high-speed engine rotation.
Data Source
AI summary
A valve system includes: a cam shaft including a shaft section and a plurality of cam element sections; and a plurality of operation members that moves the cam element sections in an axial direction. The plurality of operation members include a common operation member that is provided in common between end face cams opposed to each other of the cam element sections of two cylinders disposed adjacent to each other and continuous in ignition order and that engages with the respective end face cams when both the cam element sections are close to each other, and individual operation members that are individually provided for end face cams opposed to each other of the cam element sections of two cylinders disposed adjacent to each other and discontinuous in ignition order and end face cams located at opposite ends of a cylinder row and that engage with the respective end face cams.