Hydraulically Actuated Engine Valve With Independent Pressure System
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Solution Overview
Problem
Hydraulically actuated engine valves experience reduced control capability due to fluctuating engine oil temperature and pressure, particularly during low engine speed or idle conditions, leading to inconsistent valve operation.
Innovation Solution
A separate hydraulic system, independent of the engine oil system, provides fluid pressure to actuate the valve, using an electrically driven pump that maintains consistent pressure and temperature, independent of engine speed, allowing for precise control of hydraulically actuated valves like EGR and wastegate valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If engine oil is used to actuate hydraulically actuated valves, then the hydraulic system can be integrated with the engine lubrication system, but the valve control variability increases due to fluctuating oil temperature and pressure
Solution Approach 1:
The hydraulic system is segmented into two independent parts: the first hydraulic system using engine oil for lubrication and the second hydraulic system using a separate fluid for precise valve control. This segmentation allows each subsystem to optimize for its specific function without interference from the other, resolving the contradiction between integration benefits and control reliability.
Solution Approach 2:
The second hydraulic system is extracted from the engine oil system, creating an independent fluid circuit. By taking out the valve control function from the general lubrication system, the patent eliminates the harmful fluctuations in temperature and pressure that affect valve control, while preserving the benefits of having a hydraulic system available for valve actuation.
2Device complexity
If a single hydraulic system is used for both lubrication and valve actuation, then the system complexity is reduced, but the control precision deteriorates during low engine speed conditions
Solution Approach 1:
The hydraulic functions are segmented into two independent systems: the first system handles lubrication needs and the second system handles precision valve control. This segmentation enables the second system to maintain consistent fluid properties for precise control during low engine speed conditions, while accepting increased overall system complexity.
Solution Approach 2:
The second hydraulic system serves the universal function of providing consistent pressure for valve actuation regardless of engine operating conditions. By designing a separate system that can independently maintain pressure, the patent achieves multi-functionality where the same hydraulic infrastructure supports both high-speed and low-speed valve control requirements.
3Force
If hydraulically actuated valves are used, then the valve actuation force is improved, but the control consistency deteriorates due to temperature and pressure fluctuations
Solution Approach 1:
The valve actuation function is extracted from the engine oil circuit into a separate second hydraulic system. This extraction removes the source of temperature and pressure fluctuations, allowing the hydraulic actuation force to be maintained consistently without the instability introduced by engine oil variations.
Solution Approach 2:
The second hydraulic system is designed with local quality optimized for valve control, using fluid properties and pressure levels specifically suited for precise valve actuation. This localized optimization ensures stable fluid composition for control consistency, while the first system maintains its own characteristics for lubrication purposes.
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 repeatable and accurate control of engine valves even at low engine speeds or when the engine is off, improving valve reliability and reducing the risk of valve sticking, while maintaining thermal and lubrication benefits.
Implementation Method 1
a second hydraulic system, separate from the first hydraulic system, provides fluid pressure to actuate the valve
Data Source
AI summary
Various methods and systems are provided for controlling a hydraulically actuated engine valve. In one example, a system includes a hydraulically actuated engine valve and an engine having a first hydraulic system. The system further includes a second hydraulic system, which is separate from the first hydraulic system, and where the second hydraulic system provides fluid pressure to actuate the valve.