Variable Valve Timing Pressure Accumulator for Idle Phase 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 challenges in maintaining sufficient system pressure during idling phases, leading to reduced engine performance and increased emissions, as the pressure medium pump's capacity is insufficient to support phase adjustments at low engine speeds.
Innovation Solution
A pressure accumulator is designed with a minimum filling pressure lower than the system pressure at idle speed, ensuring it remains filled even at idling conditions, and a locking mechanism restricts the phase position within a defined angle interval, allowing the pressure accumulator to support phase adjustments without increasing the pressure medium pump's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pressure medium pump is designed to provide sufficient system pressure at idle speed, then the system pressure is adequate for phase adjustments during idling, but the pump dimensions and complexity increase
Solution Approach 1:
The pressure accumulator is pre-filled with pressure medium before the idling phase begins. This preliminary storage of pressure medium allows the system to immediately support phase adjustments when needed during idling, without requiring the pump to be oversized for this specific condition.
Solution Approach 2:
The pressure accumulator acts as an intermediary between the pressure medium pump and the phase adjustment mechanism. It buffers the pressure medium supply, decoupling the pump's continuous operation from the intermittent high-demand phases during idling, thereby allowing a smaller pump to suffice.
2Reliability
If the pressure accumulator is designed with high filling pressure above idle speed pressure, then it can support phase adjustments during idling, but the available pressure medium volume is insufficient
Solution Approach 1:
The minimum filling pressure of the pressure accumulator is set to be lower than the system pressure at idle speed. This parameter change allows the accumulator to maintain a larger volume of pressure medium while still providing sufficient pressure support during phase adjustments at idle, resolving the trade-off between pressure and volume.
3Power
If the pressure medium pump size is increased to ensure sufficient pressure during idling, then system pressure is adequate, but the device complexity and space requirements increase
Solution Approach 1:
The pressure accumulator is pre-filled with pressure medium before the idling phase begins. This preliminary storage of pressure medium allows the system to immediately support phase adjustments when needed during idling, without requiring the pump to be oversized for this specific condition.
Solution Approach 2:
The pressure accumulator acts as an intermediary between the pressure medium pump and the phase adjustment mechanism. It buffers the pressure medium supply, decoupling the pump's continuous operation from the intermittent high-demand phases during idling, thereby allowing a smaller pump to suffice.
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 configuration ensures functional reliability and rapid phase adjustments across all engine operating phases without enlarging the pressure medium pump, maintaining engine performance and reducing emissions by providing additional pressure medium during idling.
Implementation Method 1
The pressure accumulator is designed in such a way that its minimum filling pressure is less than the pressure within the pressure medium system at idle speed of the internal combustion engine
Implementation Method 2
By supplying pressure medium to or removing pressure medium from the pressure chambers, the vanes are displaced within the pressure chambers, as a result of which the rotors are rotated in a targeted manner relative to one another
Data Source
Figure 1
Figure 2a
Figure 2b
AI summary
The invention relates to a device (10) for variably adjusting the control times of gas exchange valves (9a, b) of an internal combustion engine (1). Said device comprises a drive element (22), an output element (23), at least one pressure chamber (35, 36), a pressure medium system (37) and a pressure reservoir (43), the pressure chamber (35, 36) and the pressure reservoir (43) communicating with the pressure medium system (37) and a phase position between the output element (23) and the drive element (22) being modifiable via the pressure medium system (37) by supplying a pressure medium to or discharging a pressure medium from the pressure chamber (35, 36).