Camshaft Adjuster Central Locking via Hydraulic Switching Valve
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Camshaft adjusters in internal combustion engines face uncontrolled movements and increased wear due to alternating torques when engine startup oil pressure is not yet built up, leading to undesirable noise and wear, as they are not fully filled with pressure medium during the start phase.
Innovation Solution
A hydraulic circuit with an additional control position in the switching valve allows for the camshaft adjuster to be locked in the central position during engine startup, using a five-port switching valve configuration that connects the pressure pump to working chambers A and the oil reservoir to working chambers B, ensuring the locking pins engage and prevent adjustment past the central locking position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the camshaft adjuster is provided with a locking device that locks the rotor in a central position, then the rotor is prevented from uncontrolled movements during engine startup, but the device complexity increases due to the additional locking pins and control mechanisms
Solution Approach 1:
The locking device is designed to automatically engage and disengage based on pressure medium presence. The spring-loaded locking pins self-engage with locking gates when pressure medium is absent, and self-disengage when pressure medium is applied, eliminating the need for external control mechanisms during normal operation.
Solution Approach 2:
The locking mechanism utilizes pressure medium (hydraulic or pneumatic) to control the locking pins' engagement and disengagement. The pressure medium flows through control channels to actuate the locking pins, providing a reliable and automatic locking control system.
2Stability of the object's composition
If the locking pins are spring-loaded and automatically engage when pressure medium is not applied, then the central locking position is maintained during engine shutdown, but the rotor cannot be adjusted during startup before pressure medium is built up
Solution Approach 1:
The system performs preliminary locking action during engine shutdown and startup phases before pressure medium is fully built up. The locking pins engage in advance to prevent uncontrolled movements, and the control mechanism is designed to automatically release the lock once pressure medium reaches sufficient level, enabling adjustment.
Solution Approach 2:
The locking device transitions from a static locked state during shutdown to a dynamic controlled state during startup. The spring-loaded locking pins provide automatic locking when pressure is low, and the pressure medium dynamically actuates the locking pins to release the lock when pressure builds up, enabling smooth transition between locked and adjustable states.
3Adaptability or versatility
If the switching valve has five control positions to enable locking during active pressure medium adjustment, then the camshaft adjuster can be locked in central position during startup, but the valve complexity and control system complexity increase
Solution Approach 1:
The five-port switching valve is designed to perform multiple functions across five control positions: normal operation mode, locking mode during shutdown, and locking mode during active adjustment. This multi-functional design allows a single valve to handle various operating conditions without requiring separate valves for each function.
Solution Approach 2:
The switching valve controls different flow paths and pressure distributions by changing its control parameter (position). By varying the valve position, the system can switch between different operational modes (normal adjustment, locking during shutdown, locking during active adjustment), providing adaptability through parameter changes rather than physical reconfiguration.
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 strategy effectively locks the camshaft adjuster in the central position during engine shutdown and startup, preventing uncontrolled movements and wear, even under conditions of low ambient temperatures and high oil viscosity, ensuring reliable engine operation.
Implementation Method 1
A hydraulic medium may be optionally applied to the working chambers, which is supplied to the working chambers on one side of the vanes of the rotor from a pressure medium reservoir in a pressure medium circuit via a pressure medium pump
Implementation Method 2
Locking devices of this type preferably include spring-loaded locking pins, which successively lock into locking gates provided on the sealing cover or the stator when the rotor rotates
Implementation Method 3
The control of the pressure medium flow, and thus the adjusting movement of the camshaft adjuster, includes a hydraulic multi-way switching valve, with the aid of which flow-through openings may be blocked or unblocked as a function of a position of a valve body
Data Source
AI summary
A hydraulic camshaft adjuster for changing the control times of gas exchange valves of an internal combustion engine, designed as a vane cell camshaft adjuster. A control device inserted in the vane selectively opens and interrupts a flow connection between the working chambers. A locking device prevents relative motion between the rotor and the stator in that the rotor is fastened to the stator at a vane position. A switching valve, which has three working ports, a P port and a T port, can be moved into different control positions by an adjusting element,—wherein in the control position, the P port communicates with the working chambers via the A port, the B port is blocked at the switching valve, and the T port communicates with the control device of the vanes via the C port. In a control position provided as a starting strategy for the switching valve the A port communicates with the P port and the working chambers, the B port communicates with the T port and the working chambers, and the C port communicates with the control device of the vanes and the T port.