Hydraulic Valve Locking Mechanism for High-Pressure Engine
Solution Overview
Problem
Modern compression ignition internal combustion engines face challenges with high charge pressures causing large pressure differences across gas exchange valves, leading to issues with standard valve springs opening due to insufficient closing force, and the use of stiffer springs is often impractical without significant cylinder head modifications.
Innovation Solution
A gas exchange valve arrangement that incorporates a hydraulic fluid chamber and locking piston mechanism, using hydraulic fluid to assist conventional springs, allowing for smaller, less stiff springs and reducing energy losses, with a locking valve to prevent fluid outflow and maintain valve closure even at low initial pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If standard valve springs are used, then the device complexity is low, but the valve closing force is insufficient under high charge pressures
Solution Approach 1:
The patent applies hydraulic principles by introducing a hydraulic fluid chamber and locking piston mechanism. Hydraulic fluid is introduced into the chamber to generate locking force on the piston, which then applies closing force to the gas exchange valve. This hydraulic system enables sufficient valve closing force under high charge pressures without requiring significantly stiffer conventional springs or major cylinder head modifications.
2Force
If stiffer valve springs are used, then the valve closing force is sufficient, but the cylinder head must be significantly modified
Solution Approach 1:
The hydraulic locking mechanism provides a alternative solution to stiffer springs. By using hydraulic fluid pressure acting on the locking piston, sufficient closing force is achieved without requiring the cylinder head to be redesigned for larger or stiffer springs. The system can be integrated into existing cylinder head designs with minimal modifications.
Solution Approach 2:
The locking piston acts as an intermediary between the hydraulic fluid and the gas exchange valve. The hydraulic fluid chamber and locking piston mechanism translate hydraulic pressure into mechanical closing force on the valve, providing a intermediate transmission path that avoids the need for direct spring-stiffness increases or cylinder head redesign.
3Force
If air springs are used to assist conventional springs, then the valve closing force is improved, but a separate pressurized air source and control means are needed
Solution Approach 1:
The patent uses hydraulic fluid instead of pneumatic air springs. The hydraulic system introduces fluid into a chamber to generate locking force through a locking piston, providing valve closing assistance without requiring separate pressurized air sources or complex control means. The hydraulic approach integrates more compactly with the existing engine lubrication system.
Solution Approach 2:
The system can utilize the engine's existing lube oil as the hydraulic fluid, eliminating the need for separate pressurized fluid sources. The engine's own lubrication system serves the dual purpose of lubrication and providing hydraulic fluid for the valve locking mechanism, reducing overall system complexity.
4Loss of energy
If smaller valve springs are used, then energy losses are reduced, but the valve may open unintentionally under pressure differences
Solution Approach 1:
The hydraulic locking mechanism works in conjunction with reduced-stiffness springs to provide reliable valve closure. The hydraulic fluid chamber generates locking force through the locking piston, ensuring the valve remains closed under pressure differences even when using smaller, lower-energy springs. This combination maintains both energy efficiency and closure reliability.
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 solution enables the use of smaller valve springs, reducing energy consumption and preventing unintended opening of gas exchange valves, while allowing the use of engine lube oil as hydraulic fluid, thus minimizing the need for high-pressure sources and accommodating high charge pressures without cylinder head redesign.
Implementation Method 1
a hydraulic fluid chamber, a locking piston that is attached to the gas exchange valve and provided with a piston surface delimiting the hydraulic fluid chamber and facing towards the opening direction of the gas exchange valve
Implementation Method 2
means for preventing outflow from the hydraulic fluid chamber when the gas exchange valve is closed
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The gas exchange valve arrangement for a piston engine comprises a gas exchange valve (1) and a spring (4) exerting a force on the gas exchange valve (1) for closing the valve (1). The arrangement further comprises a hydraulic fluid chamber (12), a locking piston (1C, 26) that is attached to the gas exchange valve (1) and provided with a piston surface (5A, 26A) delimiting the hydraulic fluid chamber (12) and facing towards the opening direction of the gas exchange valve (1), means (14) for introducing hydraulic fluid into the hydraulic fluid chamber (12), and means (17, 30) for preventing outflow from the hydraulic fluid chamber (12) when the gas exchange valve (1) is closed.