Variable Valve Timing Actuator Locking Control
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Solution Overview
Problem
Existing devices for variably adjusting the control times of gas exchange valves in internal combustion engines face issues with uncontrolled vibrations, increased noise, wear, and emissions during starting and idling phases due to insufficient oil pressure, leading to unintended unlocking and delayed adjustment processes.
Innovation Solution
The solution involves using separate control lines to independently control the locking states of rotation angle limiting devices, allowing for secure mechanical locking and lubrication during critical phases, preventing automatic unlocking and ensuring adequate lubrication, thus maintaining a controlled phase position independently of pressure chamber pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical locking devices are provided to couple the two rotors during critical operating phases, then uncontrolled vibrations and noise are prevented, but the device complexity increases and lubrication supply becomes insufficient
Solution Approach 1:
The locking mechanism is divided into multiple independent rotation angle limiting devices (first, second, and third), each capable of being controlled independently. This segmentation allows selective locking of specific rotor positions without requiring a complete system redesign, thereby managing complexity while maintaining reliability.
Solution Approach 2:
The locking devices are designed to engage automatically at predetermined rotation angles of the rotors. By establishing locking positions in advance during the design phase, the system ensures reliable locking during critical phases without requiring complex real-time control decisions, thus improving reliability without proportionally increasing operational complexity.
2Ease of operation
If pressure medium is supplied to the locking device to unlock the mechanical coupling, then the rotors can be adjusted freely, but during starting and idling phases the low oil pressure causes unintended unlocking and delayed adjustment
Solution Approach 1:
A separate control line is introduced as an intermediary system to control the locking devices independently from the main pressure medium circuit that supplies the pressure chambers. This separate control line can be supplied with pressure medium from the pressure chambers themselves, creating a dedicated lubrication and control pathway that operates reliably even when the main oil pressure is low during starting and idling phases.
Solution Approach 2:
The control system is segmented into two independent pathways: the main pressure medium circuit for actuating the pressure chambers, and a separate control line for managing the locking devices. This segmentation allows the locking mechanism to be controlled independently based on actual operational needs, preventing unintended unlocking during low-pressure phases while maintaining adjustment freedom when needed.
3Reliability
If all pressure chambers and locking recesses are connected to the tank during stop and start phases, then the device can be mechanically fixed in a central phase position, but the supply of lubricant to the device becomes insufficient leading to increased wear
Solution Approach 1:
The lubrication system is segmented into two separate pathways: the main pressure medium circuit connected to the tank for general lubrication, and a separate control line that remains connected to the pressure chambers to ensure continuous lubrication supply to the locking devices during stop and start phases. This segmentation ensures that while the device can be mechanically fixed in a central position, the locking mechanism continues to receive adequate lubrication through the pressure chamber connection, preventing increased wear.
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 approach ensures reliable mechanical locking and lubrication, preventing uncontrolled vibrations and emissions, and allowing for precise adjustment of gas exchange valve control times, reducing noise and wear, and maintaining a stable phase position during engine start and stop phases.
Implementation Method 1
The locking states of at least one first and one second rotation angle limiting device can be controlled by means of a separate control line that is different from the pressure medium channels of the pressure chambers
Implementation Method 2
Each of the rotation angle limiting devices can be transferred from the locked to the unlocked state by applying pressure to the respective locking recess
Implementation Method 3
a locked state in which a mechanical coupling is established between the rotors by the respective rotation angle limiting device, and an unlocked state in which the mechanical coupling between the rotors is canceled
Data Source
Figure 1~2
Figure 3a~4c
Figure 5a~6c
AI summary
The invention relates to an apparatus (1) for the variable setting of the control times of gas exchange valves of an internal combustion engine having an outer rotor (2) an inner rotor (3) which is arranged such that it can be rotated relative to the former, wherein one of the components is drive-connected to a crankshaft and the other component is drive-connected to a camshaft, having at least one pressure space (7), wherein each pressure space (7) is divided into two pressure chambers (9, 10) which act counter to one another, having a plurality of pressure medium channels, via which pressure medium can be fed to or led away from the pressure chambers (9, 10), having a plurality of rotational-angle limitation devices (12, 13, 14), wherein each rotational-angle limitation apparatus (12, 13, 14) can assume an unlocked and a locked state, wherein the locking states can be set by the supply of pressure medium to or the discharge of pressure medium from the respective rotational-angle limitation apparatus (12, 13, 14). Furthermore, a method is proposed for controlling an apparatus (1) for the variable setting of the control times of gas exchange valves of an internal combustion engine.