Vehicle Air Conditioning CO2 Sensor Upstream Placement
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Solution Overview
Problem
Existing vehicle air conditioning systems with CO2 sensors installed downstream of the evaporator in the ventilation duct face challenges in detecting CO2 leakage reliably due to large air flow cross-sections and noise issues, and may allow CO2 to spread undesirably into the vehicle compartment.
Innovation Solution
The CO2 sensor is positioned upstream of the evaporator, allowing for reliable detection of CO2 concentrations in all air conditioning modes, including fresh air, recirculating air, and mixed air modes, with minimal noise and easy installation, and is integrated with a maintenance opening for easy replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the CO2 sensor is installed downstream of the evaporator in the region of large air flow cross-section, then the installation space is sufficient, but the CO2 concentration increase may not be detected immediately due to potential leakage sites creating undetected concentration zones
Solution Approach 1:
The patent inverts the conventional sensor placement by positioning the CO2 sensor upstream of the evaporator instead of downstream. This reversal allows the sensor to detect CO2 concentration increases at the source before they disperse through the large cross-section downstream, ensuring reliable detection regardless of leakage location while maintaining sufficient installation space upstream.
2Reliability
If the CO2 sensor is installed further away from the evaporator to avoid large flow cross-section, then the leakage detection reliability improves, but installation space becomes constricted and air flow disruption causes undesired noises
Solution Approach 1:
By inverting the sensor placement to upstream of the evaporator, the patent positions the sensor in a region with more favorable flow characteristics. The upstream location provides sufficient installation space while avoiding the high-velocity, noisy flow conditions downstream, thus eliminating air flow disruption noises while maintaining reliable detection.
3Object-affected harmful factors
If the flap closes the air supply downstream of the evaporator to prevent CO2 entry, then the CO2 concentration in vehicle compartment is reduced, but CO2 can still spread in opposite direction through the intake opening
Solution Approach 1:
The patent implements preliminary action by positioning the CO2 sensor upstream of the evaporator, enabling early detection of CO2 leakage before the gas can spread through the system. This early detection allows the control system to activate preventive measures (such as closing flaps or activating ventilation) before CO2 reaches the vehicle compartment or spreads through the intake opening, thereby ensuring more effective prevention.
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 configuration ensures timely and reliable detection of CO2 leaks, preventing harmful concentrations from reaching the vehicle compartment, while reducing energy consumption and minimizing noise and installation complexity.
Implementation Method 1
a CO2 sensor (26, 26') for monitoring a CO2 concentration in the air (18)
Implementation Method 2
an evaporator (24) that is arranged in the ventilation duct (22)
Data Source
Figure 1
AI summary
The invention relates to a vehicle air conditioning system (10) for controlling the air in a vehicle internal compartment (12), having a blower unit (14) that comprises an air inlet (16) and also an air outlet (20) and can generate an air flow from the air inlet (16) to the air outlet (20); a ventilation duct (22) that connects the air outlet (20) of the blower unit (14) to the vehicle internal compartment (12); an evaporator (24) that is arranged in the ventilation duct (22), and a CO2 sensor (26) for monitoring a CO2 concentration in the air (18), wherein the CO2 sensor (26, 26') is arranged upstream of the evaporator (24) in the vehicle air conditioning system (10).