Lost Motion Valvetrain Hydraulic Conditioning for Faster Response
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Solution Overview
Problem
Hydraulic systems in engine valve actuation systems, particularly those with lost motion components, suffer from inconsistent and slow response times due to air contamination, which affects engine performance and efficiency, especially in environments with limited space and intricate pathways.
Innovation Solution
A conditioning circuit is introduced to provide a supplemental flow of hydraulic fluid and venting to maintain a refreshed state in the hydraulic circuits, using solenoid valves and supplemental flow passages in rocker shafts and rocker arms to purge air and maintain consistent fluid composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If hydraulic circuits are used to control lost motion components, then valve actuation motions can be modified and auxiliary events facilitated, but air enters the circuit causing slow and inconsistent response times
Solution Approach 1:
The conditioning circuit performs preliminary action by continuously purging air from the hydraulic circuit before it can cause response time issues. The supplemental flow passage and vent work continuously to remove air bubbles, ensuring the hydraulic fluid remains free of air contamination that would otherwise cause slow and inconsistent response times.
Solution Approach 2:
The system converts the harmful effect of air in the hydraulic circuit into a beneficial continuous purging action. The conditioning circuit uses the presence of air as an indicator to drive continuous venting and purging, transforming the air contamination problem into a self-regenerating system that actively removes air and maintains fluid quality.
2Ease of operation
If engine oil is used as hydraulic fluid and circuits are vented to ambient air, then oil can drain and air can enter the circuit, but this causes variation in response time and brake lift responsiveness
Solution Approach 1:
The conditioning circuit implements continuity of useful action by maintaining continuous purging and conditioning of the hydraulic fluid. The supplemental flow passage provides continuous flow to displace air, and the continuous venting action ensures air is constantly removed, maintaining consistent fluid composition and response characteristics throughout operation.
Solution Approach 2:
The system performs self-service through the conditioning circuit that automatically and continuously conditions the hydraulic fluid. The circuit self-regulates by continuously removing air and maintaining fluid quality without external intervention, ensuring consistent performance throughout the system's operation.
3Speed
If solenoid valves are used to control hydraulic flow, then fast turn-off can be achieved, but air contamination negatively impacts performance and response time
Solution Approach 1:
The conditioning circuit acts as an intermediary between the solenoid valve control system and the hydraulic lost motion components. It continuously conditions the hydraulic fluid by removing air, ensuring that the fast-acting solenoid valves operate with consistent and predictable response characteristics without the degrading effect of air contamination.
Solution Approach 2:
The system changes the physical parameters of the hydraulic fluid by continuously removing air and maintaining optimal fluid composition. This parameter change ensures the hydraulic fluid maintains consistent density, compressibility, and flow characteristics, allowing the solenoid valves to achieve fast and consistent response times.
4Productivity
If rapid reciprocating valvetrain parts are used, then engine braking and auxiliary valve motion are facilitated, but oil drains from the circuit around bearing clearances introducing air
Solution Approach 1:
The conditioning circuit extracts the harmful air from the hydraulic circuit through continuous venting action. The vent continuously removes air that enters through bearing clearances and part interfaces, separating and removing the air contamination from the hydraulic fluid to maintain system performance.
Solution Approach 2:
The system converts the harmful air infiltration through bearing clearances into a beneficial continuous purging cycle. The presence of air entering through rapid reciprocating motion drives the conditioning circuit to continuously vent and replace fluid, transforming air infiltration from a harmful effect into a self-regenerating purging mechanism.
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
The system ensures consistent turn-on response times and improved hydraulic fluid composition, enhancing engine performance by eliminating air from the circuits and maintaining oil pressure, even at low engine speeds.
Implementation Method 1
a conditioning circuit adapted to provide a supplemental flow of hydraulic fluid in the lost motion control flow passage
Implementation Method 2
a conditioning circuit adapted to provide a supplemental flow of hydraulic fluid in the lost motion control flow passage when the control valve is in the deactivated mode, the conditioning circuit including a vent for venting the supplemental flow from the control flow passage
Data Source
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AI summary
Hydraulic systems in an engine valvetrain having lost motion and/or braking hydraulic circuits are provided with a conditioning circuit that may include a supplemental supply passage, which provides continuous and supplemental supply of hydraulic fluid from a supply source to the braking and lost motion circuits, as well as a venting of the circuits to ambient, such that the hydraulic fluid in these circuits is kept in a refreshed and conditioned state without air contamination. A vented three-way solenoid valve may be utilized. The supplemental supply passage may be provided at various locations in the valvetrain and in the engine head environment. The supplemental supply passage may include flow and pressure control devices to control the flow of the supplemental supply of hydraulic fluid.