Cam Phaser Oil Control Valve With Self-Centering Mid-Lock
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Solution Overview
Problem
Existing oil control valves for cam phasers in internal combustion engines lack effective packaging and fail-safe mechanisms, leading to inefficiencies in cam torque recirculation and potential engine stall issues.
Innovation Solution
The design incorporates a self-centering connection and locking pin connection within the oil control valve, ensuring the rotor locks relative to the stator even when oil pressure drops, with a compact axial configuration that maintains constant pressure for self-centering and improved cam torque recirculation, featuring a piston assembly with check valves and a compression spring for axial movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the self-centering connection is permanently connected to the supply connection, then self-centering function is improved and fail-safe operation is achieved, but the valve housing complexity increases
Solution Approach 1:
The self-centering connection is merged with the supply connection, creating a permanent fluid communication path between them. This eliminates the need for separate self-centering ports or complex valve mechanisms, achieving fail-safe self-centering operation while actually simplifying the overall valve housing design by reducing the number of separate components and connections required.
2Volume of moving object
If the valve housing is configured compact in the axial direction, then packaging efficiency is improved and space is saved, but the manufacturing precision requirements increase
Solution Approach 1:
The piston assembly is nested within the valve housing in a compact axial arrangement, with the piston rod extending through the valve housing along the axial direction. This nested configuration allows the valve housing to be configured compact in the axial direction, reducing overall packaging volume while the nesting relationship provides natural alignment and positioning features that help manage manufacturing precision requirements.
3Productivity
If the piston assembly is configured for axial movement, then cam torque recirculation is improved, but the device complexity increases
Solution Approach 1:
The piston assembly serves multiple functions: it enables cam torque recirculation through axial movement, provides positioning for the rotor-stator assembly, and works with the self-centering connection to ensure fail-safe operation. This multi-functionality reduces the need for separate dedicated components for each function, thereby improving productivity without proportionally increasing device complexity.
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
This configuration enhances packaging efficiency, ensures fail-safe operation by maintaining self-centering during engine stalls, and improves cam torque recirculation, reducing the time to reach a mid-lock position and minimizing oil consumption.
Implementation Method 1
a compression check valve spring which seats the check valves
Implementation Method 2
The oil control valve may be permanently connected to the supply connection by the openings of the hollow check valve tube and to the self-centering connection by openings of the piston
Data Source
AI summary
An oil control valve for a cam phaser of an internal combustion engine, the oil control valve including a valve housing, including a first operating connection, a second operating connection, a supply connection, and a tank drain connection configured to drain a hydraulic fluid; a piston assembly, including a piston, a hollow check valve tube, a first check valve and a second check valve configured to provide cam torque recirculation, wherein the piston assembly is arranged in the housing axially displaceable by an actuator, wherein a control chamber is arranged within the piston between the first check valve and the second check valve and wherein a check valve compression spring which closes the first check valve and the second check valve is arranged within the piston between the first check valve and the second check valve.