Camshaft Adjuster Mid-Position Locking for Engine Startup
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Solution Overview
Problem
Existing camshaft adjusters in internal combustion engines face issues with maintaining the correct phase position during engine startup and shutdown, leading to potential misalignment and increased wear due to insufficient pressure medium supply, which affects starting and running properties.
Innovation Solution
A method is introduced to automatically set the camshaft to a defined phase position during engine shutdown and startup, using control positions and pressure medium management to prevent piston or vane contact with limit stops, ensuring the camshaft is locked in the correct position even without sufficient pressure medium, thereby maintaining optimal engine performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the camshaft adjuster is operated during engine startup without sufficient pressure medium supply, then the camshaft phase position can be adjusted, but the piston or vane may contact the limit stop causing wear and noise
Solution Approach 1:
The control unit delays the operation of the camshaft adjuster until a predetermined time after engine startup, ensuring that sufficient pressure medium has been supplied to the hydraulic actuator before attempting phase position adjustment. This preliminary waiting period prevents piston or vane contact with limit stops during the critical startup phase.
Solution Approach 2:
The control unit monitors engine operating parameters and uses this feedback to determine the appropriate timing for activating the camshaft adjuster. By continuously monitoring pressure medium supply conditions through engine runtime, the system ensures safe operation only when hydraulic pressure is sufficient, preventing harmful contact with limit stops.
2Productivity
If the camshaft adjuster is not locked in the correct phase position during engine shutdown, then the engine can stop freely, but the camshaft may rotate uncontrolled causing misalignment and wear
Solution Approach 1:
The control unit activates the camshaft adjuster in advance during engine shutdown to achieve the correct phase position before the engine completely stops. This preliminary positioning ensures that when the engine restarts, the camshaft is already in the correct phase position, preventing misalignment and wear during the transition.
Solution Approach 2:
The hydraulic actuator automatically maintains the camshaft phase position using residual hydraulic pressure during engine shutdown. The system leverages the existing hydraulic medium supply to keep the adjuster locked in the correct position without requiring additional active control, enabling self-maintenance of positioning accuracy during the shutdown process.
3Adaptability or versatility
If the camshaft adjuster operates without sufficient pressure medium, then phase position can be changed, but the starting and running properties of the engine deteriorate
Solution Approach 1:
The control unit implements a predetermined time delay before allowing the camshaft adjuster to operate during engine startup. This preliminary waiting period ensures that hydraulic pressure has built up to sufficient levels, enabling the adjuster to change phase position without compromising the engine's starting and running properties.
Solution Approach 2:
The system dynamically controls the availability of the camshaft adjuster based on real-time hydraulic pressure conditions. The adjuster is enabled or disabled by the control unit according to the engine's operational state, allowing phase position changes only when pressure medium supply is sufficient, thus adapting the system's versatility to current operating conditions.
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 method ensures the camshaft is accurately positioned during engine restart, reducing wear and noise, and maintaining optimal starting and running properties by preventing uncontrolled rotation and ensuring sufficient pressure medium supply.
Implementation Method 1
a hydraulic actuation device (102) which has a piston (105) or a vane (11) which can be displaced by a pressure medium
Implementation Method 2
of a spring element (113) which acts on the piston (105) or the vane (11) in the direction of the initial position
Data Source
AI summary
The invention relates to a device (101) for varying the control times of gas exchange valves of an internal combustion engine, with a hydraulic actuation device (102) and with a control valve (103). The device (101) according to the invention is provided with mid-position locking of a hydraulic actuation device (102). Furthermore, the device (101) according to the invention ensures that, in the event of the failure of an actuation unit (112) which regulates the control valve (103), the hydraulic actuation device (102) is locked in the mid-position and the lock is maintained until the actuation unit (112) is repaired. Furthermore, the device (101) according to the invention makes it possible to start the internal combustion engine in a position locked in a mid-position, without a movable element (105) of the hydraulic actuation device (102) butting against a side wall of a pressure space (104) when the internal combustion engine is started. Methods are proposed to bring the actuation device (102) into a locked mid-position, and to hold it there, for the restarting of the internal combustion engine.