Fluid Injector Tip Temperature Estimation via Coil Resistance
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Solution Overview
Problem
Fluid injectors, such as fuel injectors, are prone to irreversible damage due to excessive thermal exposure, necessitating a method to estimate the temperature of the injector tip to initiate cooling measures before damage occurs.
Innovation Solution
A system and method that utilizes the resistance of a coil in the fluid injector tip to estimate its temperature, involving a controller that supplies current to the coil, measures its resistance, and determines the tip temperature, allowing for proactive cooling when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is installed at the tip of the fluid injector to directly measure temperature, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent uses the coil as an intermediary element to indirectly measure tip temperature. Instead of placing a sensor directly at the tip, the system measures the electrical resistance of the coil, which correlates with tip temperature through thermal conduction. This intermediary approach avoids the complexity of direct tip sensing while maintaining measurement capability.
Solution Approach 2:
The patent replaces a mechanical/physical temperature sensor system with an electrical measurement system. By measuring the electrical resistance of the coil (which changes with temperature), the system substitutes a simple electrical measurement for what would otherwise require a complex physical temperature sensor at the tip location.
2Reliability
If cooling measures are initiated early to prevent tip damage, then reliability is improved, but energy consumption increases
Solution Approach 1:
The patent implements a feedback control system that continuously monitors coil resistance (indicating tip temperature) and adjusts cooling activation accordingly. When the measured resistance indicates the tip is approaching its thermal limit, the system activates cooling measures. This feedback mechanism ensures cooling is applied only when necessary, optimizing the balance between reliability and energy consumption.
Solution Approach 2:
The system takes preliminary action by monitoring temperature trends through resistance measurements and activating cooling before the tip actually reaches damaging temperatures. This preliminary intervention prevents damage while avoiding unnecessary early cooling, thereby reducing wasted energy while maintaining reliability.
3Device complexity
If the coil resistance measurement method is used to estimate tip temperature, then device complexity is reduced, but measurement precision may be affected by manufacturing variations
Solution Approach 1:
The patent addresses manufacturing variations by implementing a calibration process that adjusts the resistance-temperature relationship for each individual injector. During calibration, the actual tip temperature is measured (using a reference sensor), and the coil resistance at that temperature is recorded. This creates a customized resistance-temperature curve for each injector, compensating for manufacturing tolerances and ensuring accurate temperature estimation despite variations in coil resistance characteristics.
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
Effectively estimates the temperature of the fluid injector tip, enabling timely cooling measures to prevent damage, with a model providing higher accuracy and reducing the need for intrusive injections, while also allowing for calibration to account for manufacturing variations and operational conditions.
Implementation Method 1
a resistance of the coil is measured when the current is supplied to the coil, a coil temperature is determined based on the measured resistance
Data Source
AI summary
Systems and methods of estimating a fluid injector tip temperature. A controller having a processor and a memory supplies a current to a coil of a fluid injector, a resistance of the coil is measured when the current is supplied to the coil, a coil temperature is determined based on the measured resistance, and a tip temperature of a fluid injector tip is estimated based on the determined coil temperature.