Ultrasonic Fuel Flow Sensor Eliminates Mechanical Wear
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Solution Overview
Problem
Existing fuel flow measuring systems face issues with accuracy, durability, and pressure losses, particularly in high mass flow applications, where small inaccuracies can result in significant revenue losses, and they often require lengthy conduit sections or moving parts that are prone to wear and space constraints.
Innovation Solution
The implementation of an ultrasonic fuel flow measuring system using a conduit with upstream and downstream ultrasonic transducers that calculate fuel mass flow rate based on signal transit times and known fuel properties, including temperature, to provide accurate and durable measurements with minimal impedance to fuel flow, suitable for use with electronic engine controllers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If turbine type meters are used to measure fuel flow, then the system can provide continuous flow measurement, but the system suffers from bearing wear, friction-induced flow restriction, and limited accuracy
Solution Approach 1:
The patent replaces the mechanical turbine meter system with an ultrasonic flow measurement system that uses acoustic waves to measure fuel flow velocity. This eliminates moving parts and mechanical contact, thereby eliminating bearing wear and friction while maintaining measurement capability through non-contact ultrasonic transit time measurement
Solution Approach 2:
The patent introduces ultrasonic waves as an intermediary medium to measure fuel flow. Instead of directly measuring flow with mechanical contacts, the system uses ultrasonic signals that pass through the fuel, and the transit time of these signals provides indirect but accurate measurement of flow velocity without affecting the fuel flow itself
2Measurement precision
If orifice plate or flow section meters are used, then the system can provide differential pressure-based flow measurement, but the system incurs significant fuel flow pressure loss
Solution Approach 1:
The patent replaces differential pressure-based mechanical flow meters with an ultrasonic flow measurement system. This substitution eliminates the need for flow restriction elements like orifice plates, thereby avoiding the energy loss associated with creating pressure drops while maintaining accurate flow measurement through non-intrusive ultrasonic transit time measurement
3Measurement precision
If Venturi-type flow meters are used, then the system can provide accurate flow measurement, but the system requires a lengthy flow section that increases space and weight
Solution Approach 1:
The patent replaces the lengthy mechanical Venturi flow meter structure with a compact ultrasonic flow measurement system. By using ultrasonic transducers mounted on the conduit to measure flow through acoustic wave transit time, the system achieves accurate flow measurement without requiring long flow sections, thereby reducing overall system length and weight
4Reliability
If conventional ultrasonic flow meters are used, then the system can provide non-contact measurement, but the system suffers from limited accuracy and other disadvantages
Solution Approach 1:
The patent improves ultrasonic flow measurement accuracy by implementing temperature compensation that adjusts the speed of sound in fuel based on measured temperature. The system also calculates fuel density from temperature and uses these corrected parameters to accurately determine mass flow rate from ultrasonic transit time measurements, thereby achieving high precision while maintaining the reliability of non-contact measurement
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 offers improved accuracy and durability with reduced pressure losses, enabling precise fuel flow measurement that can be used for control systems, even in high-inertial environments, and is adaptable for various applications such as aircraft and locomotive engines.
Implementation Method 1
a first transducer arranged to direct a first signal through the conduit proximate the flow area to a second transducer, the second transducer being arranged to direct a second signal through the conduit proximate the flow area to the first transducer
Implementation Method 2
a processor for calculating a fuel mass flow rate through the conduit based at least in part on a first signal transit time for the first signal to travel from the first transducer to the second transducer, a second signal transit time for the second signal to travel from the second transducer to the first transducer
Data Source
AI summary
Methods and apparatus for measuring liquid fuel flows within a conduit are disclosed. An example flow sensor may include a conduit arranged to flow fuel therethrough along a flow axis, the conduit defining a flow area orthogonal to the flow axis. The flow sensor may further include a first transducer arranged to direct a first signal through the conduit proximate the flow area to a second transducer, the second transducer being arranged to direct a second signal through the conduit proximate the flow area to the first transducer, the first transducer being spaced apart from the second transducer by a signal path length, and in a direction parallel to the flow axis by an axial distance. The fuel flow measuring system may further include a processor arranged to calculate a fuel mass flow rate based on first and second signal transit times, known fuel properties and a fuel temperature.