Camshaft Adjuster Unlocking for Oil Pressure-Independent Engine Start
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Solution Overview
Problem
Existing camshaft adjustment mechanisms are complex and require oil pressure for operation, necessitating a simpler, oil pressure-independent adjustment system that can reliably set the rotational angle of the camshaft based on engine temperature for efficient start-up.
Innovation Solution
A second actuator, independent of the first actuator, is provided to unlock the camshaft adjuster's late-locking device, allowing oil pressure-independent actuation, and a sliding element coupled with a return spring ensures precise control and space-saving design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional oil pressure-dependent camshaft adjustment mechanism is used, then the camshaft can be adjusted during engine operation, but the structure becomes complex and requires hydraulic pressure for reliable operation
Solution Approach 1:
The camshaft adjustment system is divided into two independent actuators: a first actuator for adjusting the camshaft during operation, and a second actuator for unlocking the late-locking device. This segmentation allows each actuator to have a simpler, dedicated function, reducing overall system complexity while maintaining reliability through redundancy.
Solution Approach 2:
A locking pin with a late-locking device is introduced as an intermediary mechanical element that physically couples the second actuator to the camshaft adjuster. This mediator enables direct mechanical actuation without requiring hydraulic pressure, simplifying the control mechanism while ensuring reliable positioning.
2Adaptability or versatility
If the camshaft adjuster requires hydraulic pressure for operation, then adjustment can be made during engine operation, but the system fails when hydraulic pressure is insufficient or unavailable
Solution Approach 1:
The second actuator is designed to automatically unlock the late-locking device when hydraulic pressure falls below a minimum threshold, allowing the camshaft adjuster to self-correct and rotate into a predetermined starting position without external intervention. This self-service mechanism ensures continuous adaptability and reliability across varying pressure conditions.
Solution Approach 2:
The locking pin is pre-configured in a locked position during normal operation, and the second actuator is pre-positioned to unlock it when needed. This preliminary setup allows rapid response to pressure changes without requiring complex real-time decision-making, enhancing both adaptability and reliability.
3Ease of operation
If a second actuator is added to the system for independent actuation, then oil pressure-independent adjustment is achieved, but the number of components increases
Solution Approach 1:
The second actuator is integrated into the existing camshaft adjuster structure, sharing common mounting spaces and alignment features with the first actuator. This merging approach allows independent oil pressure-free actuation while minimizing the increase in overall component count and spatial requirements.
4Device complexity
If the locking pin is directly coupled to the actuator ram, then the structure is simple, but space for actuator arrangement is limited
Solution Approach 1:
The locking pin is coupled to the actuator ram via a sliding element that moves axially within the stator, transitioning the coupling mechanism from a radial to an axial dimension. This dimensional change allows the actuators to be arranged in a compact configuration, reducing the overall space required while maintaining structural simplicity.
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 system simplifies the structure and enables reliable, space-efficient adjustment of the camshaft, ensuring precise positioning and efficient engine start-up regardless of hydraulic pressure fluctuations.
Implementation Method 1
The ram and/or the sliding element can be preloaded by a (respective individual) return spring into a rest position arranged in a powerless manner relative to the locking pin
Data Source
AI summary
The disclosure relates to a camshaft adjustment system comprising a hydraulic camshaft adjuster having a stator and a rotor forming at least one working chamber. The at least one working chamber is divided into a first sub-chamber and a second sub-chamber The sub-chambers interact with a control valve controllable via a first actuator. When the first sub-chamber undergoes a volume increase, the rotor is displaced into a late position relative to the stator, and when the second sub-chamber undergoes a volume increase, the rotor is displaced into an early position relative to the stator. A second actuator actuated independently of the first actuator is provided. In order to release the camshaft adjuster from the late position when in an operating state, a ram of the second actuator displaces a locking pin of a late-locking device of the camshaft adjuster out of its position that locks the late position.