Vehicle air conditioning system and method for operating such a system
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Solution Overview
Problem
Vehicle air conditioning systems face the issue of 'flash fogging' due to residual water in the evaporator evaporating and condensing on window panes during ventilation mode, leading to reduced visibility and the need for energy-intensive cooling mode to prevent it.
Innovation Solution
A method that calculates water collection and drainage in the evaporator, determining if a critical quantity exceeds a limit value, automatically switching to cooling mode only when necessary, using moisture and temperature sensors to manage air flow and drainage, thereby preventing flash fogging and optimizing energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vehicle air conditioning system is operated in cooling mode to prevent flash fogging, then the window panes remain clear of condensation, but energy consumption increases significantly
Solution Approach 1:
The control device calculates the water collection quantity in the evaporator based on operating parameters (air flow rate, temperature difference, humidity) and compares it with drainage capacity to determine residual water risk. This feedback mechanism enables intelligent switching between cooling and ventilation modes, activating cooling only when residual water exceeds a threshold and would cause flash fogging, thereby preventing flash fogging while minimizing unnecessary energy consumption.
Solution Approach 2:
The system performs preliminary calculation of water collection quantity and drainage capacity before mode switching decisions. By predicting the residual water situation in advance based on current operating conditions, the system can proactively switch to cooling mode when needed and switch to energy-saving ventilation mode when safe, preventing flash fogging before it occurs while optimizing energy use.
2Use of energy by moving object
If the vehicle air conditioning system is operated in ventilation mode to save energy, then energy consumption is reduced, but flash fogging occurs due to sudden evaporation of residual water
Solution Approach 1:
The control device continuously monitors operating parameters and calculates water collection quantity versus drainage capacity to assess residual water risk. This feedback enables the system to identify when ventilation mode would cause flash fogging and automatically switch to cooling mode, allowing energy-saving ventilation operation whenever safe while preventing flash fogging when residual water is present.
Solution Approach 2:
The system calculates the expected residual water situation before mode switching, enabling proactive prevention. By predicting whether residual water would evaporate and cause flash fogging under planned ventilation operation, the system can pre-switch to cooling mode or extend drainage time, allowing energy-saving operation whenever possible while preventing harmful flash fogging.
3Reliability
If the evaporator is kept cool continuously to prevent flash fogging, then window panes remain clear, but the air conditioning system consumes excessive energy
Solution Approach 1:
The system dynamically adjusts the evaporator temperature state based on real-time calculation of residual water risk. Instead of continuous cooling, the evaporator is cooled only when the calculated water collection quantity exceeds drainage capacity indicating residual water presence. This dynamic adaptation allows the system to maintain flash fogging prevention reliability while minimizing energy waste by operating in ventilation mode when safe.
Solution Approach 2:
The control device changes the operational parameter of evaporator temperature based on calculated residual water conditions. When residual water risk is detected, the system switches to cooling mode to maintain low evaporator temperature; when safe, it switches to ventilation mode allowing evaporator warming. This parameter change strategy prevents flash fogging only when necessary, avoiding continuous cooling energy waste.
4Use of energy by moving object
If the vehicle air conditioning system switches modes frequently to optimize energy use, then energy consumption is reduced, but control complexity increases
Solution Approach 1:
The control device uses a systematic feedback approach, calculating water collection quantity from measurable operating parameters (air flow rate, temperature difference, humidity) and comparing with drainage capacity. This structured feedback mechanism provides clear switching criteria based on residual water risk, enabling intelligent mode optimization without excessive control complexity. The calculation-based approach is more systematic than simple timer-based switching.
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
Reliably prevents flash fogging by ensuring the evaporator remains cooled only when needed, reducing energy consumption by operating in cooling mode only when necessary, and allowing for efficient drainage and drying during ventilation mode.
Implementation Method 1
water condenses in the evaporator from the air to be fed to the interior of the vehicle
Implementation Method 2
the condensed water collected in the evaporator is suddenly evaporated
Implementation Method 3
a fan for producing an air flow to be fed to an interior of the vehicle through the evaporator
Data Source
AI summary
The invention relates to a method for operating an air conditioning system for a vehicle including the steps of:calculating a water collection quantity in an evaporator during the operating period of a cooling mode of the air conditioning system,calculating a quantity of drainage water from the evaporator,determining a quantity of water present in the evaporator at a certain point in time, andcomparing the determined quantity of water in the evaporator with a predetermined limit value at the point in time of starting the vehicle or at the point in time of starting the ventilation mode of the air conditioning system.The cooling mode of the air conditioning system is activated if the limit value is exceeded and otherwise the ventilation mode of the air conditioning system is activated.