Viscosity-Independent Flow Restrictor with Radial Throttle
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Solution Overview
Problem
Existing flow limiters in internal combustion engines are viscosity-dependent, leading to functional failures at varying fuel viscosities, and suffer from wear issues, as they rely on pressure drops and element movement that are affected by viscosity, resulting in incomplete closing during malfunctions.
Innovation Solution
A flow limiter design with a radially arranged channel outside the chamber, using a spherical closing element and a throttle that is viscosity-independent, ensuring the closing element does not move during permissible injection quantities, and only closes after a predetermined maximum injection is exceeded or during continuous injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional flow limiter with a closing element (ball or piston) is used that moves in response to pressure differences, then the device can provide a closing function to prevent continuous injection, but the closing function becomes viscosity-dependent and may fail at varying fuel viscosities
Solution Approach 1:
The flow limiter is divided into two independent functional parts: a viscosity-independent throttle that creates a pressure drop, and a closing element that responds only to this pressure drop. The throttle is separated from the chamber containing the closing element, with the channel running radially outside the chamber. This segmentation allows the throttle to handle viscosity variations while the closing element maintains reliable operation across different viscosities.
Solution Approach 2:
The throttle acts as an intermediary element that converts fuel flow rate variations into pressure differences. Instead of the closing element directly responding to fuel viscosity and flow rate, the throttle mediates by creating a pressure drop that the closing element then responds to. This intermediary function isolates the closing element from viscosity-dependent effects.
2Productivity
If the closing element moves in response to injection quantities to provide flow limitation, then the device can regulate fuel flow, but wear increases due to continuous movement and interaction with sealing surfaces
Solution Approach 1:
The system separates the flow regulation function (performed by the viscosity-independent throttle) from the closing function (performed by the closing element). The closing element only moves when a malfunction is detected, rather than continuously moving to regulate normal flow variations. This reduces wear on the closing element and its sealing surfaces.
Solution Approach 2:
The throttle automatically compensates for normal injection quantity variations and fuel viscosity changes without requiring the closing element to move. The closing element serves itself by remaining stationary during normal operation and only activating when truly needed, thereby minimizing wear while maintaining protective function.
3Device complexity
If the channel runs through the chamber or closing element as in conventional designs, then the structure is simpler, but the closing element may flow around or through the channel, compromising the closing function
Solution Approach 1:
The channel is segmented from the chamber containing the closing element. The channel runs radially outside the chamber, creating distinct flow paths: one for normal fuel flow through the throttle, and another for the closing element to seal against the outlet. This spatial segmentation prevents the closing element from interfering with or flowing around the channel.
Solution Approach 2:
The channel is arranged in a different spatial dimension relative to the chamber - specifically, radially outside rather than through the chamber volume. This dimensional repositioning allows the channel to connect inlet and outlet while maintaining clear separation from the closing element's sealing path, eliminating the risk of flow-around without significantly increasing complexity.
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 design maintains the closing function across an extended viscosity range and enhances wear resistance by eliminating viscosity-dependent pressure drops and movement, ensuring reliable shut-off even at low injection pressures.
Implementation Method 1
a closing element (6) which is longitudinally displaceable in a chamber (3) between an initial position and an end position and is spring-biased counter to the flow direction
Implementation Method 2
at least one channel having a throttle (10), wherein the channel (13) runs radially outside the chamber (3)
Data Source
Figure 1
AI summary
The device for restricting the feed of fuel from a high-pressure supply, via a controllable injector, into the combustion chamber of an internal combustion engine comprises a housing with a pressure supply-side housing inlet and an injector-side housing outlet which are hydraulically connected to one another via at least one channel which has a throttle, and a closing member which can be displaced longitudinally in a chamber between a starting position and an end position, is spring-biased counter to the flow direction and controls a flow connection between the housing inlet and the housing outlet, wherein the at least one channel extends radially outside the chamber.