Valve Timing Control Apparatus with Variable Clearance Locking
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Solution Overview
Problem
Existing valve timing control apparatuses experience increased hydrocarbon emissions during engine idling due to maintained relative rotation phases, and generate excessive hitting sounds due to torque fluctuations, which necessitate a reduction in noise and emission levels.
Innovation Solution
A valve timing control apparatus with a driving-side and driven-side rotation member, featuring advanced and retarded angle chambers, stoppers, and lock mechanisms that allow for selective phase locking and release, enabling reduced clearance angles to minimize noise and emissions by optimizing the relative rotation phase during engine operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the relative rotation phase is maintained at a predetermined phase during engine idling, then the engine start performance is improved, but hydrocarbon emissions increase
Solution Approach 1:
The valve timing control apparatus dynamically changes the relative rotation phase between the driven-side rotation member and driving-side rotation member based on engine operating conditions. During engine start, the phase is locked at a predetermined position for optimal performance. During idling, the phase is automatically adjusted to a different position to reduce hydrocarbon emissions. This dynamic adaptation allows the system to optimize for different operational requirements without manual intervention.
2Object-generated harmful factors
If the relative rotation phase is changed during engine idling to reduce hydrocarbon emissions, then emissions are restrained, but valve timing control complexity increases
Solution Approach 1:
The valve timing control apparatus incorporates automatic detection of engine operating conditions and self-adjustment of the relative rotation phase without requiring external control systems or complex control algorithms. The system monitors engine parameters and automatically transitions between different phase positions, enabling emissions reduction during idling while maintaining relatively simple control architecture.
3Object-affected harmful factors
If the clearance angle is increased to reduce noise, then hitting sounds are reduced, but valve timing precision deteriorates
Solution Approach 1:
The valve timing control apparatus applies different clearance angle values for different operating conditions and phase positions. Rather than using a uniform clearance angle throughout all operations, the system optimizes the clearance angle locally for each specific condition, allowing sufficient clearance to prevent hitting sounds during certain operations while maintaining tighter tolerances during critical timing events to preserve precision.
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 apparatus effectively reduces hydrocarbon emissions and hitting sounds by optimizing the relative rotation phase and clearance angles, enhancing engine efficiency and operational quietness.
Implementation Method 1
a torsion spring is arranged between the inner rotor and the housing for generating a biasing force so that the relative rotation phase is shifted in the advanced angle direction
Implementation Method 2
An intermediate lock passage is formed at the inner rotor to apply a pressure of hydraulic oil in a direction in which each of the intermediate lock members is retracted from the intermediate lock groove
Implementation Method 3
The most retarded angle lock member projects to the most retarded angle lock groove by a biasing force of a spring
Data Source
AI summary
A valve timing control apparatus includes a driving-side rotation member, a driven-side rotation member, a first lock mechanism selectively achieving a first lock state in which a relative rotation phase of the driven-side rotation member relative to the driving-side rotation member is locked at an intermediate lock phase and a first lock release state, and a second lock mechanism selectively achieving a second lock state in which the relative rotation phase is locked at one of a most advanced angle phase and a most retarded angle phase and a second lock release state, the driven-side rotation member being rotatable relative to the driving-side rotation member by a first clearance angle in the first lock state, the driven-side rotation member being rotatable relative to the driving-side rotation member by a second clearance angle in the second lock state, the second clearance angle being smaller than the first clearance angle.