Vehicle Cabin Airflow Control Using Humidity-Based Occupancy Detection
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Solution Overview
Problem
Existing air conditioning systems in vehicles struggle to determine the number of passengers accurately and efficiently, which is necessary to maintain minimum air quality standards, often requiring expensive sensors for CO2 measurement.
Innovation Solution
The method involves using air-conditioning measurement values and operating parameters to calculate the total water mass flow produced by passengers, allowing the system to determine the number of passengers using temperature and humidity sensors, thereby eliminating the need for expensive CO2 sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CO2 sensors are used to determine the number of passengers, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces water vapor as an intermediary substance to indirectly determine passenger count. Instead of directly measuring CO2 levels with complex sensors, the system measures water vapor concentration produced by passengers through respiration and metabolism. This intermediary approach allows using simpler, more cost-effective humidity sensors while maintaining measurement capability.
Solution Approach 2:
The patent replaces the mechanical/electronic CO2 sensing system with a humidity-based measurement system. By substituting CO2 sensors with temperature and humidity sensors, the system achieves passenger count determination through measuring water vapor production rather than carbon dioxide concentration, thereby reducing device complexity and cost.
2Measurement precision
If expensive triple sensors are used for air temperature, humidity and carbon dioxide content, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the CO2 measurement function from the triple sensor system and replaces it with an alternative approach. By removing the CO2 sensor component and using water vapor measurement instead, the system maintains air quality monitoring capability while eliminating the need for expensive triple sensors that simultaneously measure temperature, humidity, and CO2.
Solution Approach 2:
The patent employs inexpensive temperature and humidity sensors in place of expensive triple sensors. These simpler, more affordable sensors provide sufficient measurement capability for determining passenger count through water vapor concentration, making the system more cost-effective without requiring high-end expensive sensor assemblies.
3Use of energy by moving object
If fresh air volume flow is reduced to permissible minimum, then energy consumption is reduced, but air quality may deteriorate
Solution Approach 1:
The patent implements dynamic adjustment of fresh air volume flow based on real-time passenger count determination. By continuously monitoring water vapor concentration and calculating the number of passengers, the system dynamically optimizes fresh air supply to match actual occupancy levels, ensuring energy efficiency while maintaining air quality standards.
Solution Approach 2:
The patent establishes a feedback loop where air quality parameters (water vapor concentration, temperature) are continuously measured, passenger count is calculated, and fresh air volume flow is adjusted accordingly. This closed-loop control system ensures that energy consumption is minimized while air quality requirements are consistently met by adapting to changing occupancy conditions.
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 allows for cost-effective determination of the passenger count with an accuracy within a +/-10% tolerance, enabling the air conditioning system to maintain minimum air quality standards while reducing operational costs.
Implementation Method 1
temperature and humidity sensors are sufficient, the measurement values of which form the basis in a suitable manner for determining the current number of passengers located in the passenger compartment
Data Source
AI summary
A method for operating an air conditioning system for a vehicle for transporting persons. The air conditioning system, depending on the current number of passengers in a passenger compartment of the vehicle (level of occupation), controls a fresh air volume flow to be introduced into the passenger compartment from outside the vehicle in order to maintain a predefined minimum ambient air quality. The air conditioning system determines a total water mass flow, which is currently produced by the passengers in the passenger compartment, on the basis of air-conditioning measurement values and a current value for at least one operating parameter of the air conditioning system. From the total water mass flow and a predefined value for a water mass flow produced by a single passenger, the system determines the current number of passengers in the passenger compartment. There is also described an air conditioning arrangement for carrying out the method.