Injector Mass Characterization via Pressure Sensors
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Solution Overview
Problem
Existing flow rate measurement techniques, such as those based on Coriolis force, are inadequate for determining the mass of fluid delivered by injectors with short opening times, as they require continuous fluid flow and cannot account for shot-to-shot variations, which are critical for injector characterization.
Innovation Solution
A device equipped with pressure sensors, temperature measurement/ regulation, and ultrasound sound sensors to determine the mass of fluid delivered by an injector on a single-shot basis, allowing for precise calculation of fluid mass differences before and after injection, and optionally using a sound emitter and receiver to average fluid parameters along multiple paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Coriolis force-based measuring instruments are used for flow rate measurement, then continuous fluid flow measurement is achieved, but measurement precision for short-duration injector shots is lost
Solution Approach 1:
The patent replaces the mechanical Coriolis force-based measurement system with a pressure-based measurement system. Instead of using a mechanically vibrating tube to detect fluid flow, the invention uses pressure sensors to monitor pressure changes in a known volume, from which fluid mass is calculated using the ideal gas law. This substitution enables single-shot measurement capability while simplifying the mechanical complexity of the measurement system.
Solution Approach 2:
The patent introduces an intermediary calculation method using the ideal gas law (pV=nRT) as a mediator between pressure measurement and fluid mass determination. Rather than directly measuring fluid flow, the system measures pressure changes in a controlled volume and uses the known relationship between pressure, volume, temperature, and moles of gas to calculate the mass of fluid injected. This intermediary approach enables precise single-shot measurements.
2Loss of information
If multiple rapid injections are performed to generate quasi-homogeneous fluid flow, then continuous flow measurement is possible, but shot-to-shot variation information is lost
Solution Approach 1:
The patent uses preliminary action by pre-characterizing the relationship between pressure change and fluid mass injection for the specific system configuration. The system establishes the initial pressure, known volume, and temperature conditions before each injection, allowing direct calculation of injected mass from the pressure change without requiring multiple injections to establish flow characteristics. This enables single-shot measurement while preserving shot-to-shot variation information.
3Measurement precision
If pressure sensors are used to determine fluid mass in the housing, then single-shot measurement capability is achieved, but temperature measurement and regulation becomes necessary
Solution Approach 1:
The patent applies self-service by using the existing thermal environment of the system rather than requiring active temperature control. The measurement method assumes isothermal conditions and uses the known or measurable temperature of the system to calculate fluid mass. If temperature varies, the system can measure it with a simple temperature sensor and use it in the calculation, rather than requiring complex active temperature regulation. This reduces the complexity of the temperature control system while maintaining measurement precision.
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 accurate, single-shot measurement of fluid mass delivered by an injector, providing detailed characterization and potentially automating the testing process, while simulating relevant practical configurations by adjusting pressure and flow conditions.
Implementation Method 1
at least one pressure sensor for pressure measurement is provided in the housing, in order to determine the mass of the fluid in the housing by means of an evaluation unit on the basis of the pressure determined
Implementation Method 2
at least one temperature sensor, which noninvasively delivers information about the temperature in the housing
Implementation Method 3
a sound sensor and a sound emitter, preferably operating in the ultrasound range, may be fitted preferably on the inside of the housing, so that sound waves, which propagate through the fluid and are received by the sound sensor, are emitted by the sound emitter
Implementation Method 4
at least one temperature regulator, which produces a predefined temperature in the housing
Data Source
AI summary
The invention relates to a device for determining the mass of fluid (2) discharged by an injector (13), the device comprising a housing (1) which is impermeable to fluid and which serves for storing fluid, said housing having an injector port (11) for the connection, in particular of an inlet (12), of the injector (13) and having a fluid port (8) for the infeed of fluid (2), wherein at least one pressure sensor (3) for pressure measurement is provided in the housing (1) in order, by way of an evaluation unit (17), to determine the mass of the fluid (2) in the housing (1) in a manner dependent on the determined pressure.