Central Tire Inflation System Compressor Control for Dryer Purging
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Solution Overview
Problem
Central tire inflation systems (CTIS) face issues with condensation in flow passages, which can lead to damage and reduced effectiveness due to the need for air purging of dryers, causing low air pressure and potential leaks in pneumatically-operated valves.
Innovation Solution
A CTIS with a control system that determines the compressor activation period and adjusts air pressure to perform either a full or partial purge of the dryer, minimizing compressor deactivation and reactivation, and using excess pressure to maintain operational efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the dryer is purged by reverse-flowing air through the dryer at high pressure, then condensation is reduced and the dryer is cleaned, but air pressure in the reservoir decreases which reduces the effectiveness of the CTIS and pneumatically-operated valves
Solution Approach 1:
The system performs a preliminary compression phase where the compressor builds up air pressure in the reservoir to an elevated level before the purge operation. This preliminary action ensures that when air is later routed through the dryer for purging, sufficient pressure remains in the reservoir to maintain valve operation effectiveness.
Solution Approach 2:
The system implements periodic compressor operation with distinct phases: a first period where the compressor supplies air to build elevated pressure, and a second period where the purging system operates. This periodic action separates the pressure-building function from the purging function, ensuring that pressure is restored before each purge cycle.
2Use of energy by moving object
If the compressor is frequently deactivated and reactivated, then energy consumption is reduced, but wear on the compressor increases and life is reduced
Solution Approach 1:
The system maintains continuous compressor operation during both the pressure-building phase and the purging phase by keeping the compressor activated throughout. This eliminates deactivation and reactivation cycles, reducing mechanical wear on the compressor while still achieving energy efficiency through optimized operational periods.
3Object-generated harmful factors
If air is removed from the CTIS for purging the dryer, then the dryer is purged of liquid, but low air pressure in the reservoir reduces the effectiveness of the CTIS and pneumatically-operated valves
Solution Approach 1:
The system performs preliminary compression to build elevated air pressure in the reservoir before initiating the purge operation. This ensures that when air is routed through the dryer, the reservoir maintains sufficient pressure for effective valve operation throughout and after the purge cycle.
Solution Approach 2:
The system changes the pressure parameter by operating at an elevated target pressure during the purge phase rather than maintaining constant operating pressure. This temporary pressure elevation allows the system to tolerate the pressure drop during purging while still maintaining adequate pressure for valve operation.
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
The system ensures efficient air management, reducing wear on the compressor and maintaining sufficient pressure for valve operation, thereby extending compressor life and preventing damage from condensation.
Implementation Method 1
condensed liquids, usually condensed water from the air flowing through the system
Implementation Method 2
The dryer extracts water from the air
Implementation Method 3
the dryer must be purged by reverse-flowing air through the dryer at high pressure
Implementation Method 4
expansion of water on freezing can lead to blockages or damage and cracking or splitting of components
Data Source
AI summary
A central tire inflation system (CTIS) for a vehicle includes a reservoir for supplying air to the vehicle tires, a pressure sensor for monitoring air pressure in the reservoir, a compressor for supplying compressed air along a first flow path to the reservoir, a compressor timer for monitoring the run-time of the compressor, a dryer disposed on the first flow path for drying air supplied by the compressor, a purging system for routing air through the dryer along a second flow path to purge liquid from the dryer, and a controller for controlling the flow of air in the CTIS. The controller is configured: to activate the compressor in response to a request for a compressor operation, after which operation the air in the reservoir is at a post-operation pressure; when the compressor operation is complete, to determine a compressor activation period, and to determine if the compressor activation period is greater than or equal to a target period; and if the compressor activation period is less than the target period, to keep the compressor activated until pressure in the reservoir increases to a base target pressure greater than the post-operation pressure; and if the compressor activation period is greater than or equal to the target period, to keep the compressor activated until pressure in the reservoir increases to an elevated target pressure higher than the base target pressure and to activate the purging system to route air from the reservoir to purge the dryer of liquid.