Trailer Air Tank Quick-Fill Control for Faster Brake Charging
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Solution Overview
Problem
The extended fill time of trailer air tanks due to a small orifice in the trailer dash valve restricts the flow of compressed air, leading to undesirable situations where trailer spring brakes are released before the air tank is sufficiently charged, especially when a 'spring brake priority' valve is engaged.
Innovation Solution
A controller on the tractor portion of an articulated vehicle receives an electrical signal to unpark the trailer and transmits an electrical output signal for quick-fill mode, allowing supplemental compressed air to be communicated to the trailer air tank, increasing the volumetric flow and reducing fill time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If compressed air passes through a small orifice in the trailer dash valve, then the tractor air tank is protected from downstream failures, but the charging time of the trailer air tank is extended
Solution Approach 1:
The air flow path is segmented into two separate paths: a restricted path through the orifice for normal protection, and an unrestricted quick-fill path through the bypass valve. This allows the system to maintain protection while enabling rapid filling when needed.
Solution Approach 2:
The bypass valve acts as an intermediary component that provides an alternative flow path around the restrictive orifice. It mediates between the need for protection (through the orifice) and the need for rapid filling (through the bypass), allowing both functions to coexist.
2Ease of operation
If a spring brake priority valve releases trailer parking brakes before charging the air tank, then the trailer can be unparked, but the trailer service brakes may not be sufficiently charged for safe operation
Solution Approach 1:
The system performs preliminary action by rapidly filling the air tank through the bypass valve immediately when the unpark command is received, before the brakes are released. This ensures the tank is charged in advance, eliminating the safety risk of operating with insufficient air pressure.
Solution Approach 2:
The system implements a two-stage periodic action: first, rapid filling through the bypass valve to charge the tank quickly; second, normal restricted flow through the orifice to maintain pressure. This periodic switching between fill modes ensures both quick unparking and brake safety.
Data Source
AI summary
A controller on a tractor portion of an articulated vehicle includes an electrical input port adapted to receive an electrical input signal based on a command to unpark a trailer portion of the articulated vehicle and an electronic processor adapted to: receive the electrical input signal from the electrical input port; identify, based on the electrical input signal, when the command to unpark the trailer is received at the electrical input port; and based on the command to unpark the trailer, transmit an electrical output signal to an electrical output port for causing supplemental compressed air to be communicated from the tractor to the trailer for filling an air tank on the trailer using a quick-fill mode.