VCT Phaser Air Venting for Hydraulic Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hydraulically-actuated variable camshaft timing (VCT) systems in internal combustion engines face instability and performance issues due to air entrainment in the hydraulic fluid, leading to compressibility, noise, vibration, and durability problems.
Innovation Solution
Incorporation of air vents in the VCT phaser assembly to remove air from the hydraulic fluid, enhancing hydraulic stiffness and system stability by locating air vents at the center of rotation region or in specific components like plates and the rotor, allowing air separation and exit during rotational motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air is present in the hydraulic fluid of the VCT phaser assembly, then the system becomes more compressible and less stable, but adding air vents increases device complexity
Solution Approach 1:
The patent extracts air from the hydraulic fluid by incorporating air vents in the VCT phaser assembly. The air vents are strategically positioned to allow air to escape from the hydraulic fluid while maintaining the sealed hydraulic system, thereby improving system stability without requiring external air removal equipment
Solution Approach 2:
The air venting system is designed to automatically vent air from the hydraulic fluid during normal operation of the VCT phaser assembly. The air vents are positioned to utilize the natural motion and pressure changes within the system to facilitate air separation and escape, eliminating the need for external air removal systems
2Speed
If air vents are added to the VCT phaser assembly, then hydraulic stiffness and responsiveness improve, but manufacturing complexity increases
Solution Approach 1:
The air vents are integrated into the existing components of the VCT phaser assembly, such as the housing, rotor, or plates, rather than being separate add-on components. This merging of air venting functionality into existing structural elements improves responsiveness while minimizing the impact on manufacturing processes
Solution Approach 2:
The air vents serve multiple functions: they allow air to escape from the hydraulic fluid, maintain the sealed hydraulic system, and do not interfere with the normal advance and retard functionalities of the VCT device. This multi-functionality approach improves responsiveness without requiring separate dedicated air removal systems
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 air venting system improves hydraulic stiffness and responsiveness, reducing compressibility and enhancing overall system stability and performance by effectively purging air from the fluid chambers, thus minimizing noise, vibration, and harshness issues.
Implementation Method 1
The air vent(s) is located at a center of rotation region of the particular component(s) in which it resides. The center of rotation region is with respect to rotational motion of the hydraulically-actuated VCT phaser assembly. Amid use, air brought to the center of rotation region and received in the air vent(s) escapes hydraulic fluid that remains in the hydraulically-actuated VCT phaser assembly.
Data Source
AI summary
A hydraulically-actuated variable camshaft timing (VCT) phaser assembly is employed for use in an automotive internal combustion engine. The VCT phaser assembly has a housing, a rotor, a first plate, a second plate, and a control valve. The rotor is situated within the housing, and a plurality of chambers are established between the rotor and housing. The first plate is situated on one side of the housing and rotor, and the second plate is situated on an opposite side of the housing and rotor. One or more air vents reside in one or more of the housing, rotor, first plate, second plate, or control valve. Air separated from hydraulic fluid in the VCT phaser assembly amid use and that makes its way to the air vent(s) can escape the VCT phaser assembly.