Valve Catch Piston Seating Velocity Control
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Solution Overview
Problem
Existing systems for controlling engine valve seating velocity in internal combustion engines, particularly in hydraulic lost motion systems and Variable Valve Actuation designs, face challenges in precisely managing valve closure due to fixed cam profiles and hydraulic fluid flow rates, leading to suboptimal valve seating control.
Innovation Solution
A hydraulic lost motion system comprising a housing with fluid passages, pistons, and a valve catch piston with seating passages and a spring, allowing for selective hydraulic fluid communication and control to regulate valve seating velocity, enabling earlier valve closure and adaptive seating control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fixed cam profile is used to actuate engine valves, then the valve actuation timing is determined by the cam lobe size and location, but the valve seating velocity cannot be precisely controlled when earlier closure is required
Solution Approach 1:
The patent employs a dynamic valve actuation system where a piston can be rapidly moved within a cylinder to control valve timing. The system transitions from a static cam profile to a dynamic mechanism where hydraulic fluid control enables real-time adjustment of valve closure timing and velocity, resolving the contradiction between precise control and timing flexibility
Solution Approach 2:
The invention uses hydraulic fluid to control piston movement and valve actuation. By regulating hydraulic fluid flow to and from the piston, the system achieves precise control over valve seating velocity and timing, enabling earlier closure when needed while maintaining adaptability across different operating conditions
2Loss of time
If hydraulic fluid is rapidly released to an accumulator or oil sump to achieve earlier valve closure, then valve seating control is required, but the system complexity increases with additional control mechanisms
Solution Approach 1:
The piston assembly serves multiple functions: it acts as both the actuator for valve movement and the control element for timing adjustment. The same hydraulic passages and fluid control mechanisms that drive valve opening also control closure timing, reducing the need for separate control systems and minimizing overall system complexity
Solution Approach 2:
The valve control mechanism is nested within the existing hydraulic lost motion system architecture. The piston, cylinder, and hydraulic passages are integrated into the cam-driven mechanism, with the control functionality embedded within the actuation system itself rather than added as a separate external control system
3Manufacturing precision
If all seating events occur as a result of hydraulic fluid release in common rail Variable Valve Actuation designs, then valve seating control is achieved, but the valve seating velocity is governed by hydraulic flow rate rather than cam profile
Solution Approach 1:
The system controls valve seating velocity by changing hydraulic flow rate parameters. By adjusting the rate of hydraulic fluid release from the piston chamber, the system directly controls the velocity at which the valve closes, enabling precise seating control independent of cam profile while maintaining ease of operation through hydraulic flow regulation
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 effectively controls engine valve seating velocity by regulating hydraulic fluid flow, allowing for precise valve closure timing and velocity management, enhancing engine performance and efficiency across various operating conditions.
Implementation Method 1
a valve catch spring disposed in the valve catch piston hollow interior
Implementation Method 2
hydraulic fluid communication between the one or more side passages and the one or more first piston fluid passages is selectively occluded
Data Source
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Figure 5
AI summary
Hydraulic lost motion systems and methods for actuating an internal combustion engine valve include a master piston slidably disposed in a housing. One or more master piston fluid passages extend from a bore provided in the master piston and register with a fluid passage extending through the housing. A slave piston is slidably disposed in a lower portion of the master piston bore and a valve catch piston is slidably disposed in an upper portion of the master piston bore. The valve catch piston may have a hollow interior, a lower end orifice extending from the hollow interior through a lower end of the valve catch piston, one or more side passages extending through a side portion of the valve catch piston, and one or more seating passages extending through the valve catch piston wall.