Sensing Wire Grid for Dynamic Fuel Spray Measurement
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Solution Overview
Problem
Current methods for characterizing fuel spray distribution in combustion engines are limited by their inability to measure spatial characteristics over time, providing only static and inaccurate data, which is inadequate for dynamic applications like fuel injectors.
Innovation Solution
A measurement device with sensing wires that heat up and measure ohmic resistance changes due to impinging fuel spray particles, allowing for the determination of both temporal and spatial flow distribution of a liquid spray stream, using multiple grids of parallel sensing wires to capture two-dimensional or three-dimensional data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a grid of cells is used to measure fuel spray distribution, then a static characterization of total flow is obtained, but the measurement accuracy and temporal resolution are limited
Solution Approach 1:
The patent replaces the mechanical grid cell system with an optical measurement system using light sources and photodetectors. This substitution enables non-contact, high-speed temporal measurements while maintaining spatial distribution characterization, thereby improving both measurement precision and temporal resolution simultaneously.
Solution Approach 2:
The patent changes the measurement parameter from integrated total flow (static) to time-resolved light absorption signals (dynamic). By measuring the temporal variation of light absorption at multiple spatial positions, the system captures both spatial distribution and temporal evolution of the spray, resolving the contradiction between static accuracy and temporal resolution.
2Measurement precision
If grid cells with defined dimensions are used for measurement, then spatial distribution data is obtained, but the measurement accuracy is limited by cell dimension
Solution Approach 1:
The patent transitions from a two-dimensional grid cell array to a multi-point optical measurement system that samples along linear paths through the spray. This dimensional change allows higher spatial resolution without the complexity of a dense 2D grid, as photodetectors can be positioned at multiple locations along the spray trajectory to capture detailed spatial distribution.
3Loss of information
If traditional measurement methods are used, then only static flow distribution is characterized, but dynamic spray characteristics cannot be measured
Solution Approach 1:
The patent employs periodic pulsed light sources that illuminate the spray at high frequency, synchronized with the spray injection cycles. This periodic action enables capture of multiple spray events, allowing statistical analysis of dynamic spray characteristics and improving measurement speed while preserving temporal information.
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
Enables precise and dynamic measurement of fuel spray distribution, providing detailed spatial and temporal data that improves the characterization of fuel injection processes in combustion engines, enhancing accuracy and resolution beyond traditional methods.
Implementation Method 1
measuring an ohmic resistance change of the sensing wire resulting from a cooling of the sensing wire caused by particles of the liquid spray stream impinging onto the sensing wire
Implementation Method 2
By means of the electric current flowing through the sensing wire, the power supply unit is operable to heat the sensing wire
Data Source
AI summary
A measurement device for measuring a flow distribution of a liquid spray stream which has been atomized by a nozzle may comprise: a sensing wire; at least one further sensing wire; an electric power supply; a measurement unit; and a second grid of parallel sensing wires. The sensing wires may be positioned within a spray volume of the liquid spray stream and arranged in parallel with respect to each other to form grids of parallel sensing wires. The electric power supply unit may supply an electric current to the sensing wires. The measurement unit may measure an ohmic resistance change of the sensing wires. The first axis defined by the parallel sensing wires of the first grid and a second axis defined by the parallel additional sensing wires of the second grid may enclose a slanted angle.