Ultrasonic Coolant Level Sensor Standpipe Design
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Solution Overview
Problem
Existing methods for estimating coolant levels in a coolant reservoir are inconsistent due to temperature variations and sensor degradation, and may fail to differentiate between low and empty coolant levels, leading to poor cooling performance and potential engine overheating.
Innovation Solution
A system using a vertical, hollow standpipe fluidically coupled to the coolant overflow container, with an ultrasonic sensor that transmits signals from the bottom to the top and adjusts power based on echo times to accurately estimate coolant levels, reducing inaccuracies from thermal fluctuations and vehicle motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an ultrasonic sensor is installed at the bottom of the coolant reservoir to estimate fluid level, then the sensor can detect coolant presence, but the estimated coolant level becomes inconsistent due to temperature variations and sensor degradation
Solution Approach 1:
A vertical hollow standpipe is introduced as an intermediary component between the coolant reservoir and the ultrasonic sensor. The standpipe fluidically couples to the reservoir and provides a controlled measurement environment that isolates the sensor from thermal fluctuations and vehicle motion effects, thereby improving measurement consistency without sacrificing accuracy
Solution Approach 2:
The patent replaces direct mechanical contact sensing (sensor at reservoir bottom) with acoustic wave-based measurement (ultrasonic echo timing). This substitution eliminates the issues of sensor degradation from thermal exposure and provides more reliable measurements by using sound wave propagation time rather than direct physical contact
2Measurement precision
If the ultrasonic sensor is positioned at the bottom of the container, then it can detect fluid level, but it becomes unclear whether the fluid level is low or empty
Solution Approach 1:
The measurement range is segmented into distinct zones using reference markers positioned at specific heights within the standpipe. These markers create clear visual or detectable thresholds that differentiate between 'low level' and 'empty' states, providing unambiguous information to the control system about the coolant status
3Measurement precision
If higher power is supplied to the ultrasonic transducer to maintain echo detection, then the number of first-order echo returns increases, but energy consumption increases
Solution Approach 1:
The power supplied to the ultrasonic transducer is made dynamic rather than static. The control system continuously monitors echo return quality and adjusts the transmit power level in real-time, increasing power only when detection reliability is insufficient and reducing power when adequate echoes are being received, thereby optimizing the balance between measurement precision and energy consumption
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 approach enhances the accuracy and reliability of coolant level estimation, optimizes sensor output, and reduces power consumption while preventing engine overheating by accurately detecting low coolant levels.
Implementation Method 1
periodically transmitting a sensor signal from a bottom to a top of a vertical, hollow tube fluidically coupled to the reservoir at each of the bottom and the top; receiving an echo of the transmitted signal
Implementation Method 2
receiving an echo of the transmitted signal; based on an average duration elapsed between the transmitting and the receiving
Implementation Method 3
adjusting a power of the periodically transmitted signals based on an average duration elapsed between the transmitting and the receiving
Data Source
AI summary
Methods and systems are providing for improving engine coolant level estimation to reduce engine overheating. The level of fluid in a coolant overflow reservoir is inferred based on the fluid level in a hollow vertical standpipe fluidically coupled to the reservoir at top and bottom locations, while the fluid level in the standpipe is estimated based on output from an ultrasonic signal transmitted by a sensor positioned in a recess at the bottom of the vertical standpipe. Sensor power usage is optimized based on the ratio of first order and higher order harmonic echo times in the raw data set generated by the sensor.