Hydraulic Camshaft Adjuster Center-Locking Mechanism
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Solution Overview
Problem
Conventional hydraulic camshaft adjusters face challenges in implementing a reliable center-locking mechanism, especially at low rotational speeds and negative engine oil temperatures, where friction increases, leading to uneven camshaft alternating torque, and existing solutions cannot integrate with conventional oil-pressure-actuated systems.
Innovation Solution
A hydraulic camshaft adjuster with a locking piston to control hydraulic medium flow, enabling a reliable center-locking mechanism that locks the rotor to the stator independently of the vane position, activated by a magnetically controlled hydraulic valve, and includes spring-loaded locking pins and check valves for secure engagement and fluid control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a center-locking mechanism is implemented in a conventional hydraulic camshaft adjuster, then reliable locking in central position is achieved, but the system becomes dependent on camshaft alternating torque which is uneven at low speeds and negative temperatures
Solution Approach 1:
The patent replaces the camshaft alternating torque-dependent mechanical locking mechanism with a hydraulic locking mechanism. The hydraulic locking piston is actuated by hydraulic pressure from the hydraulic medium, independent of camshaft torque. This substitution eliminates the dependency on uneven camshaft alternating torque while maintaining reliable center-locking functionality across all operating conditions including low speeds and negative temperatures.
Solution Approach 2:
The patent introduces a hydraulic medium as an intermediary to transfer energy for the locking mechanism. Instead of directly using camshaft alternating torque to drive the locking piston, the hydraulic medium acts as a mediator that stores and delivers the necessary energy through hydraulic pressure, enabling reliable locking independent of the camshaft's torque characteristics at different operating conditions.
2Reliability
If end stop locking is used instead of center-locking, then mechanical fixing is simple and reliable, but the control precision and ability to maintain central position is reduced
Solution Approach 1:
The patent implements a dynamic locking mechanism that can operate at multiple positions (central, advance, retard) rather than being fixed to a single end stop position. The hydraulic locking piston can be actuated at any vane position to achieve locking, providing both the simplicity of mechanical fixing and the precision of central position control. The system transitions from static end-stop locking to dynamic multi-position locking.
3Reliability
If a hydraulic locking mechanism is added to provide center-locking, then reliable locking is achieved, but the device complexity increases
Solution Approach 1:
The patent makes the hydraulic medium control device serve multiple functions: it controls the hydraulic medium flow for the locking mechanism, regulates the hydraulic pressure, and enables both center-locking and advance/retard locking operations. By making this single device multi-functional, the patent avoids adding separate dedicated components for each function, thereby limiting the increase in device complexity while achieving reliable locking.
Solution Approach 2:
The patent combines the hydraulic medium control functions with the locking mechanism into an integrated system. The hydraulic medium control device is merged with the locking piston and vane assembly, allowing the same hydraulic system to perform both flow control and locking operations. This merging reduces the number of separate components and simplifies the overall structure compared to having distinct independent 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
Ensures consistent engine starting by locking the rotor relative to the stator in the center-locking position without engine control unit intervention, preventing uncontrolled oscillations and noise, and operates independently of engine oil pressure, with no additional installation space required.
Implementation Method 1
a switchable hydraulic medium control device being furthermore present in the vane, which is designed to selectively release and interrupt a fluid connection, such as a line, a channel or an opening, from one chamber to the other chamber
Implementation Method 2
the locking device including at least one pin which is able to establish a form-locked fit with a stator-fixed component or is engaged therewith, such as a locking pin, a locking bolt, a locking piston or a locking journal
Implementation Method 3
activated by a magnetically controlled hydraulic valve
Data Source
AI summary
A hydraulic camshaft adjuster, including a rotor and a stator and a hydraulic medium management system, by which at least two chambers separated by a rotor-fixed vane can be or are connected to a hydraulic medium supply device and/or hydraulic medium discharge device by an interposed hydraulic valve, wherein the vane contains a switchable hydraulic medium control device designed for selective release and interruption of a fluid connection from one chamber to the other chamber. A locking device for excluding a rotational movement between the rotor and the stator locks the rotor to the stator in a vane position in which the volume of the two chambers is approximately equal, and includes a pin, interlockable with a stator-fixed component, designed to control the inflow and/or outflow of hydraulic medium to/from a chamber.