Vehicle HVAC Sensor Shielding for Accurate Evaporator Airflow Sensing
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Solution Overview
Problem
Current air conditioning system sensors for motor vehicles struggle to accurately measure the temperature of airflow passing through the evaporator due to interference from heat radiation from adjacent heating elements, leading to potential malfunctions or a frozen evaporator.
Innovation Solution
The air conditioning system incorporates a temperature sensor with a heat shield and additional thermal insulation to isolate the sensitive portion from heat radiation, allowing it to accurately measure the airflow temperature downstream of the evaporator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the temperature sensor is positioned close to the evaporator to measure airflow temperature, then the measurement responsiveness is improved, but the measurement precision deteriorates due to heat radiation from adjacent heating elements
Solution Approach 1:
A heat shield is introduced as an intermediary component between the temperature sensor and the heating elements. The heat shield blocks thermal radiation from the heating elements from reaching the sensor, while allowing the sensor to remain positioned close to the evaporator for responsive measurement of airflow temperature.
Solution Approach 2:
The heat shield extracts or removes the harmful thermal radiation from the measurement environment by blocking it before it reaches the sensor, effectively separating the useful thermal signal (from evaporator airflow) from the harmful thermal interference (from heating elements).
2Measurement precision
If the sensor is positioned to avoid heat radiation from heating elements, then the measurement precision is improved, but the device complexity increases due to additional heat shield components
Solution Approach 1:
The heat shield is merged with the temperature sensor assembly, forming an integrated unit. This combination ensures that the heat shield and sensor are positioned and oriented correctly relative to each other, while still protecting the sensor from thermal radiation. The mounting structure integrates both components into a single assembly that is installed as one unit.
3Measurement precision
If the sensor measures evaporator surface temperature by contact, then the measurement precision is improved, but the reliability deteriorates due to risk of damaging the evaporator during installation
Solution Approach 1:
The measurement function is extracted from direct contact with the evaporator surface. Instead of clamping the sensor directly to the evaporator tubes or inserting it between fins, the sensor measures the temperature of airflow downstream of the evaporator, eliminating mechanical contact and the associated risk of damage during installation.
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 effectively prevents the impact of thermal radiation from adjacent heat sources, enabling reliable temperature measurement of the airflow passed through the evaporator, thus enhancing the efficiency and preventing malfunctions of the air conditioning system.
Implementation Method 1
specifically the influence of adjacent heating elements such as a standard heater core, a PTC, an inner condenser and the like... heat radiation causing, especially at low air flow rates, malfunction of the AC-system
Implementation Method 2
The HVAC consists of a blower and a housing comprising an evaporator... Commonly known heating elements exchange heat from a coolant medium to an airflow passing by
Data Source
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AI summary
The object of the invention is, among others, an air conditioning system (1) for a motor vehicle comprising: a housing (3) for a first fluid (AF), wherein the housing (3) comprises at least one port (3a) in its structure, a first heat exchanger (5) configured to heat exchange with the first fluid (AF), at least one second heat exchanger (7) configured to generate a heat radiation (HR), and at least one sensor (9) configured to be fixed to the port (3a) so that at least a portion of the sensor (9) is located between the first heat exchanger (5) and the second heat exchanger (7), characterized in that the sensor (9) further comprises at least one sensitive portion (95) being at least partially isolated from the heat radiation (HR) generated by the second heat exchanger (7).