Vehicle Air Dryer Purge Control for Moisture Management
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Solution Overview
Problem
Current vehicle compressed air systems require a second dryer for long charge times, increasing cost and space due to a single, inadequate purge cycle that fails to regenerate the desiccant effectively, leading to moisture accumulation and system inefficiency.
Innovation Solution
A system with a service reservoir pressure sensor, a compressor, an air dryer, and a CPU that determines the number of purges needed based on dryer throughput, allowing for multiple purges before recharging, thereby regenerating the desiccant efficiently and reducing moisture accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single purge cycle is used to regenerate the air dryer, then the system structure remains simple, but the dryer cannot be effectively regenerated during long charge cycles, leading to moisture accumulation and requiring a second dryer
Solution Approach 1:
The system dynamically adjusts the number of purge cycles based on the charge cycle duration. A sensor detects whether the charge cycle exceeds a predetermined time threshold, and the CPU controller automatically increases the number of purge cycles accordingly. This dynamic adaptation allows effective dryer regeneration during long charge cycles without requiring a second dryer, resolving the contradiction between reliability and device complexity.
2Reliability
If the number of purges is increased to effectively regenerate the dryer during long charge times, then dryer regeneration effectiveness improves, but system complexity and cost increase due to requiring a second dryer
Solution Approach 1:
The system uses a sensor to detect charge cycle duration and dynamically controls the CPU to execute multiple purge cycles when needed. This allows a single dryer to be effectively regenerated during long charge cycles by increasing purge frequency, eliminating the need for a second dryer and reducing both quantity of components and system complexity while maintaining reliable regeneration.
3Productivity
If multiple purges are implemented based on charge cycle duration, then moisture removal effectiveness improves, but control system complexity increases
Solution Approach 1:
The control system uses a simple time-based threshold detection method where a sensor monitors charge cycle duration and triggers multiple purge cycles when the threshold is exceeded. This dynamic control approach improves moisture removal efficiency during long charge cycles while keeping the control logic relatively simple, avoiding excessive complexity in the control system.
Solution Approach 2:
The system incorporates feedback through a sensor that detects charge cycle duration and provides information to the CPU controller. Based on this feedback, the controller automatically adjusts the number of purge cycles. This feedback mechanism enables adaptive moisture removal efficiency improvement without requiring complex manual intervention or overly complicated control systems.
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 enables the use of a single dryer, reducing costs and space requirements while maintaining system functionality during extended charge phases by effectively purging moisture, allowing for continuous operation without the need for additional dryers.
Implementation Method 1
compressed air passes through an air dryer and moisture or water is collected by a desiccant in the dryer
Implementation Method 2
the system automatically purges the dryer (the 'purge phase') with a flow of air from a purge reservoir located downstream of the air dryer, through a purge orifice and through the dryer. This purge regenerates the desiccant in the air dryer
Data Source
AI summary
A method and apparatus provide multiple consecutive purges of an air dryer in a vehicle compressed air system. A dryer throughput sensor has an output indicative of the amount of compressed air that is passed through the dryer. In response, a CPU determines the number of purges needed to purge the dryer; and a valve is operated by the CPU to initiate multiple purges of the dryer when the compressor is unloaded.