Inward-Opening Pressure Relief Valve for High-Pressure Injection Systems
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Solution Overview
Problem
Current scavenging valves in common-rail heavy oil injection systems for internal combustion engines suffer from high leakage and jamming risks due to high system pressures, requiring excessive actuation forces and large installation spaces, especially at pressures up to 2200 bar.
Innovation Solution
The design incorporates an inward-opening seat valve with an axially displaceable control piston actuated by compressed air, minimizing leakage and jamming risks, and features a separate valve seat sleeve for easy replacement, ensuring reliable sealing and reduced actuation forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spring-loaded seat valves of the outward opening type are used, then sealing against high system pressure is achieved, but very high spring forces are required leading to large installation space and high actuation forces
Solution Approach 1:
The valve member is designed to open inwards towards the high-pressure side instead of outwards. This inversion allows the high system pressure to act on the larger surface area of the valve member, generating sealing forces that increase with pressure, thereby eliminating the need for large springs and reducing installation space.
Solution Approach 2:
The high system pressure itself serves as the sealing force source. The pressure acting on the valve member's surface area automatically generates the necessary sealing force, making the system self-regulating and eliminating the need for external spring mechanisms.
2Ease of operation
If slide valves are used, then valve operation is simple, but high pressure constantly present in the valve guide leads to constant leaks and particle accumulation causing valve jamming risk
Solution Approach 1:
By inverting the opening direction, the valve member opens towards the high-pressure side, allowing pressure to assist sealing rather than force leakage. The valve guide is positioned to receive fuel from the low-pressure side, preventing particle accumulation and jamming while maintaining operational simplicity.
3Device complexity
If outward opening seat valves are used, then valve structure is simple, but high actuation forces are required to keep the valve open during operation
Solution Approach 1:
The inward opening design reverses the force balance. High pressure acts on the valve member to assist opening, while the spring only needs to provide closing force. This dramatically reduces the actuation force required to maintain the open position during high-pressure operation.
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 provides a leak-free and reliable sealing mechanism at high pressures, reducing actuation forces and minimizing wear, while allowing for efficient temperature control and emergency pressure reduction without deactivating injectors.
Implementation Method 1
the actuating means comprise an axially displaceable control piston which is arranged on the low-pressure side and which interacts with the valve member... a compressed air source which can be connected to a pressure-tight chamber of the valve body in which the control piston can be displaced axially under the action of compressed air
Implementation Method 2
seat valves of the internally opening design have the advantage that the rail pressure to be sealed increases the sealing effect of the flushing valve. The higher the pressure to be sealed, the higher the sealing forces
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a flushing valve for common rail heavy oil injection systems for internal combustion engines, comprising a valve body (19), a valve element (22) that can be moved in the valve body (19) between an open position and a closed position, which valve element interacts with a valve seat (21) in the closed position and separates a high-pressure region from a low-pressure region, a high-pressure-side feed (26), which can be connected to a heavy oil high-pressure accumulator (rail) (8), at least one low-pressure-side discharge (29), which can be connected to a return line (18), and actuating menas for actuating the valve element (22), wherein the valve element (22) opens inward toward the high-pressure side.