Dryer Inlet Temperature Compensation Using Heater Voltage Feedback
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Solution Overview
Problem
Existing clothes dryers face inaccuracies in determining air inlet temperature due to radiation effects from the heating element, which affects cycle time and load mass estimation, as the radiation varies with heating element wattage and age.
Innovation Solution
A method to compensate the inlet temperature by determining the voltage across the heating element, using a voltage detection circuit to provide a correction factor for the thermistor readings, ensuring accurate temperature estimation and improved cycle time calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the inlet temperature is determined using a thermistor near the heating element, then the temperature measurement is simple and direct, but the measurement accuracy deteriorates due to radiation effects from the heating element
Solution Approach 1:
The system uses feedback by continuously monitoring the heating element voltage and using it to dynamically adjust the temperature compensation calculation. The controller reads the actual voltage across the heating element during operation and applies this information to correct the thermistor reading, creating a closed-loop compensation system that adapts to real-time operating conditions
Solution Approach 2:
The invention introduces an intermediary compensation mechanism that acts as a mediator between the thermistor reading and the final temperature value. Instead of directly trusting the thermistor reading, the system uses the heating element voltage as an intermediary parameter to calculate a correction factor, which then adjusts the raw temperature measurement to account for radiation effects
2Productivity
If the heating element radiation is increased to improve drying efficiency, then the drying speed increases, but the temperature measurement accuracy deteriorates due to increased radiation interference
Solution Approach 1:
The system dynamically changes the compensation parameter based on the heating element voltage. As the voltage (and thus radiation output) changes during operation, the compensation calculation automatically adjusts to match the current radiation level. This allows the system to maintain measurement accuracy across varying productivity levels without requiring physical repositioning of sensors
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 of air inlet temperature measurement, leading to precise cycle time estimation and load mass calculation, thereby improving the efficiency and reliability of the drying process.
Implementation Method 1
determining a voltage across the heating element and an inlet temperature, wherein the controller determines a compensated inlet temperature based on the inlet temperature and the heater voltage
Implementation Method 2
The inlet temperature may be considered a function of the voltage across the heating element
Implementation Method 3
a heating element for heating the air to treat the laundry load
Implementation Method 4
inaccurate temperature value, such as by influence by radiation from a heating element
Data Source
AI summary
A method for operating a laundry treating appliance, such as a clothes dryer, having a treating chamber, an air system for supplying and exiting air from the treating chamber, a heating element for heating the air to the treating chamber, and a controller determining an inlet temperature used as a control input for a cycle of operation.