Rotatable Valve Cam Phase Adjustment Mechanism
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Solution Overview
Problem
Existing valve drives for internal combustion engines lack flexibility in adjusting the opening time point of gas exchange valves, limiting their thermodynamic optimization.
Innovation Solution
A valve drive system that allows adjustable angular positioning of valve-actuating cams relative to both the main camshaft and cam carrier, enabling variable phase positioning and independent adjustment of axial and angular positions using an actuating device, which can shift the opening time point and optimize engine performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the cam carrier is axially displaced to select different valve-actuating cams, then the opening time point and opening duration can be adjusted, but the flexibility in adjusting the opening time point is limited
Solution Approach 1:
The valve-actuating cam is made rotatable relative to the cam carrier through a bearing connection, allowing dynamic adjustment of the angular position. This enables the opening time point to be varied continuously by rotating the cam, rather than being limited to discrete positions achieved through axial displacement alone.
Solution Approach 2:
The invention adds a rotational degree of freedom to the existing axial displacement mechanism. By allowing angular adjustment of the valve-actuating cam relative to the cam carrier, the system transitions from one-dimensional (axial) adjustment to two-dimensional (axial + angular) adjustment, significantly increasing the flexibility in controlling valve actuation timing.
2Adaptability or versatility
If multiple valve-actuating cams are provided for different cam groups, then different opening characteristics can be achieved, but the adjustment range for opening time point remains constrained
Solution Approach 1:
Instead of providing multiple fixed cams for different cam groups, the invention makes a single valve-actuating cam rotatable relative to the cam carrier. This dynamic adjustment mechanism allows one cam to replace multiple fixed cams by varying its angular position, thereby reducing the number of cams needed while expanding the adjustment range.
Solution Approach 2:
The rotatable valve-actuating cam serves multiple functions that would otherwise require separate fixed cams. By rotating the cam to different angular positions, the same cam can provide different opening time points and characteristics, making it a universal component that replaces multiple specialized cams.
3Measurement precision
If the valve-actuating cam is rotatably supported with adjustable angular position, then precise control of opening time point is achieved, but the device complexity increases
Solution Approach 1:
The bearing connection between the valve-actuating cam and cam carrier provides a simple yet effective rotational adjustment mechanism. This dynamic connection allows precise angular positioning to be achieved through straightforward mechanical means without complex actuation systems.
Solution Approach 2:
The rotatable cam design allows the system to self-adjust the opening time point through angular positioning. The cam's rotation naturally varies the timing of valve actuation based on its angular position relative to the cam carrier, eliminating the need for complex external control mechanisms.
Data Source
AI summary
A valve drive of an internal combustion engine is disclosed , having at least one main camshaft, on which at least one cam carrier is provided such that it is fixed so as to rotate with said main camshaft and can be displaced axially between at least two axial positions, wherein at least one valve actuating cam for actuating a gas exchange valve of the internal combustion engine is assigned to the cam carrier. The valve actuating cam is mounted rotatably and a rotary angular position of the valve actuating cam with regard to the cam carrier can be set by means of an adjusting device.