Cone-Shaped Valve Catch Piston for Seating Velocity Control
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Solution Overview
Problem
In internal combustion engines, hydraulic lost motion systems often cause engine valves to impact their seats at high velocities due to rapid fluid release, leading to potential damage, and there is a need for a system that can control valve seating velocity consistently across various operating conditions without relying on fixed cam profiles.
Innovation Solution
A valve seating device comprising a housing, an outer piston with an internal hydraulic passage, and a catch piston with a cone-shaped extension that progressively throttles fluid flow to slow the valve's closing velocity, ensuring consistent and controlled seating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If hydraulic fluid is rapidly released from the lost motion system to close the valve earlier, then valve timing is improved, but valve closing velocity increases causing damaging impact
Solution Approach 1:
The patent introduces a valve seating device with a pin and hydraulic circuit as an intermediary between the lost motion system and the valve. This intermediary controls the hydraulic fluid release rate, allowing the valve to close earlier while preventing damaging impact velocities by mediating the energy transfer through controlled fluid discharge.
Solution Approach 2:
The patent changes the parameter of hydraulic fluid release rate from rapid/uncontrolled to controlled/regulated. By using a valve seating device with a pin that controls fluid discharge through a restricted passage, the system transforms the abrupt parameter change (rapid release) into a gradual parameter change (controlled release), achieving early closure without damaging velocity.
2Manufacturing precision
If a fixed cam profile is used to control valve motion, then valve lift is determined, but valve timing cannot be adjusted for different operating conditions
Solution Approach 1:
The patent transforms the static fixed cam profile system into a dynamic adjustable system by incorporating a lost motion device with variable length capability. The hydraulic lost motion system can dynamically adjust its effective length based on operating conditions, allowing the valve timing to be varied while maintaining the precision valve lift defined by the cam profile.
Solution Approach 2:
The patent segments the valve train into distinct functional components: the fixed cam profile for precise lift control, the variable length lost motion device for timing adjustment, and the valve seating device for controlled closure. This segmentation allows each component to perform its specialized function independently, achieving both precision and adaptability.
3Speed
If the valve return spring is made stiff to enable quick valve closing, then valve closing speed is improved, but valve impact force on the seat increases
Solution Approach 1:
The patent applies beforehand cushioning by introducing a valve seating device with hydraulic damping that activates before the valve completes its closing motion. The restricted hydraulic passage creates fluid resistance that cushions the valve approach to the seat, reducing impact force while allowing the stiff return spring to maintain quick closing speed.
Solution Approach 2:
The patent uses hydraulics to decouple the relationship between closing speed and impact force. The hydraulic fluid in the valve seating device provides a controllable resistance that dissipates kinetic energy during valve closure, allowing high closing speeds from the stiff spring while preventing high impact forces through fluid damping.
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 solution effectively reduces the wear and damage on both the engine valve and its seat by progressively slowing the valve's closing velocity, maintaining consistent seating control across different engine operating conditions.
Implementation Method 1
a catch piston with a cone-shaped extension that progressively throttles fluid flow to slow the valve's closing velocity
Implementation Method 2
hydraulic lost motion systems often cause engine valves to impact their seats at high velocities due to rapid fluid release
Data Source
AI summary
A variable valve actuation system to actuate and control the seating velocity of an internal combustion engine valve is disclosed. The system comprises: a housing having a bore formed therein; an outer piston slidably disposed in the bore, said outer piston having an internal hydraulic passage, an internal chamber defined by an outer piston side wall, and an internal orifice connecting the internal hydraulic passage and the internal chamber; a catch piston slidably disposed in the outer piston; and a cone-shaped extension extending from the inner piston, wherein the cone-shaped extension is adapted to provide a variable flow area through the outer piston orifice to provide improved engine valve seating.