Compact Cam Phaser Control Valve with Nested Check Valves
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Solution Overview
Problem
Existing control valves for cam phasers are complex and costly, with inefficient fluid flow management, leading to suboptimal camshaft phase adjustment and potential space constraints in engine valve trains.
Innovation Solution
A compact control valve design featuring a cylindrical housing with a control piston device, check valves, and a supply tube with stop elements, utilizing light metal materials and a compression coil spring for efficient cam torque recirculation and fluid flow management, ensuring quick and reliable operation across various positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a compact control valve design is implemented, then space is saved and assembly is simplified, but ensuring reliable fluid flow management and cam torque recirculation becomes more challenging
Solution Approach 1:
The control valve employs a nested structure where the supply tube is positioned within the control chamber, check valves are integrated into the supply tube, and the compression coil spring is housed within the control chamber. This nesting arrangement allows multiple functional components to occupy overlapping spatial volumes, achieving a compact overall valve size while preserving all necessary fluid flow paths and functional separations.
Solution Approach 2:
The invention utilizes axial positioning along the camshaft axis to organize components vertically. The supply tube extends axially within the control chamber, with check valves positioned at different axial locations. This axial dimensionality allows efficient space utilization and maintains distinct functional zones for fluid supply, control, and recirculation within a compact radial footprint.
2Reliability
If stop elements are added to limit axial movement of check valves, then supply connection reliability during cam torque recirculation is ensured, but device complexity increases
Solution Approach 1:
The stop elements are integrated directly into the supply tube structure as axial protrusions, eliminating the need for separate restraint mechanisms. The check valves themselves engage with these stop elements through their own structural features, creating a self-contained system where components serve dual functions: fluid flow control and positional limitation.
3Speed
If check valves are made from light metal materials, then response speed is enhanced and moving weight is minimized, but manufacturing precision and durability requirements increase
Solution Approach 1:
The invention changes the material parameter from traditional heavy metals to light metals (aluminum or magnesium alloys), which have higher strength-to-density ratios. This material parameter change enables faster response speeds due to reduced mass, while the inherent properties of these alloys allow achievement of required sealing tolerances through precision casting or machining processes.
4Volume of moving object
If the control valve is designed to be compact in axial direction, then space for additional functional components is created, but ensuring proper fluid flow paths and check valve movement becomes more difficult
Solution Approach 1:
The control valve is segmented into distinct functional zones: the control chamber for pressure regulation, the supply tube for fluid delivery, check valves for directional control, and the compression coil spring for reset functionality. Each segment has a dedicated axial position and function, allowing compact arrangement while maintaining clear fluid flow paths and independent component operation.
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 design simplifies assembly, reduces weight and material costs, enhances response speed, and maintains reliable operation by ensuring uniform fluid flow and minimizing component complexity, thereby facilitating quicker camshaft adjustments and efficient phase orientation control.
Implementation Method 1
a compression coil spring arranged between the first disc portions
Implementation Method 2
the first check valve is configured with a first disc portion and a second disc portion and the second check valve is configured with a first disc portion and a second disc portion. The check valves are arranged offset from each other by a compression coil spring, so that a control chamber is formed between the first disc portions. The second disc portions are axially movable on the supply tube.
Data Source
AI summary
A control valve for a cam phaser of an internal combustion engine, the control valve including a cylindrical 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 control piston device, including a control piston, a supply tube, a first check valve and a second check valve enabling cam torque recirculation, wherein the control piston device is arranged in the housing and axially movable by an actuator, wherein the first check valve is configured with a first disc portion and a second disc portion and the second check valve is configured with a third disc portion and a fourth disc portion and the first check valves and the second check valve are arranged offset from each other by a compression coil spring.