Trailer Brake Pilot Control Circuit with Proportional Modulation
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Solution Overview
Problem
Conventional trailer brake systems in tractor-trailer combinations have varying levels of braking performance due to fixed hydraulic gain in trailer brake valves, making it difficult for operators to adjust brake pressure effectively, especially with changing regulatory requirements for lower and higher outlet pressures.
Innovation Solution
A braking system that includes a pressurized fluid supply, hydraulic and pneumatic base valves, a proportional control valve, and a controller that adjusts brake pressure by determining a brake command based on detected pressures from the work machine's brake system, allowing for adjustable modulation of both hydraulic and pneumatic brake pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed gain hydraulic brake valve is used in the trailer brake system, then the system structure is simple, but the braking performance varies and cannot be adjusted to meet changing regulatory requirements
Solution Approach 1:
The patent applies the dynamics principle by replacing the fixed gain hydraulic brake valve with an electrohydraulic valve set that includes a proportional solenoid valve. This allows the valve to dynamically adjust its opening degree based on electrical control signals, enabling continuous modulation of hydraulic pilot pressure to the trailer brake valves. The system transitions from a static, fixed-pressure design to a dynamic, adjustable-pressure system that can adapt to different regulatory requirements and braking conditions.
Solution Approach 2:
The patent applies the mechanics substitution principle by replacing the purely mechanical fixed gain brake valve with an electrohydraulic control system. The proportional solenoid valve converts electrical signals into proportional hydraulic pressure control, substituting mechanical linkage and fixed orifice designs with electrohydraulic actuation. This allows precise electronic control of brake pressure while maintaining hydraulic force multiplication.
2Adaptability or versatility
If the hydraulic component of the trailer brake system is not modulated, then the system is simpler to operate, but the braking performance cannot be optimized for different conditions
Solution Approach 1:
The patent applies the self-service principle by enabling the operator to adjust the hydraulic gain of the trailer brake valves through the cab display and control interface. The electrohydraulic valve set responds automatically to operator inputs, allowing real-time modulation of brake pressure without requiring manual mechanical adjustments. The system serves itself by converting electrical control signals into proportional hydraulic pressure changes, eliminating the need for manual intervention in pressure regulation.
3Adaptability or versatility
If separate control systems are used for hydraulic and pneumatic brake components, then each component can be optimized independently, but the overall system complexity increases
Solution Approach 1:
The patent applies the merging principle by using a single electrohydraulic valve set to control both hydraulic and pneumatic brake systems simultaneously. The proportional solenoid valve generates a single hydraulic pilot pressure signal that is distributed to control both types of brake components. This unified control approach reduces the number of separate control valves needed while maintaining independent optimization capabilities for each brake type through shared electronic control.
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
Enables adjustable modulation of trailer brake pressure, improving braking performance and compliance with changing regulatory standards by simultaneously controlling hydraulic and pneumatic brake systems, ensuring consistent and effective braking across different trailer types.
Implementation Method 1
a solenoid valve disposed in fluid communication with the proportional control valve, where the solenoid valve is movable between an open position and a closed position
Implementation Method 2
a proportional control valve fluidly coupled to the supply, the proportional control valve including an outlet disposed in fluid communication with the inlets of the hydraulic base valve and the pneumatic base valve
Implementation Method 3
a shuttle valve movably actuated between a first position and a second position, the shuttle valve being fluidly coupled between the proportional control valve and the service brake valve; wherein, the shuttle valve is disposed in the first position when the brake pressure from the service brake valve is greater than an output pressure from the proportional control valve
Data Source
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AI summary
A braking system of a trailer and work machine includes a pressurized fluid supply (402), a hydraulic base valve (226) fluidly coupled to the supply, and a pneumatic base valve (302) fluidly coupled to the supply. A proportional control valve (410) is also fluidly coupled to the supply, and it includes an outlet (244) disposed in fluid communication with the inlets of the hydraulic base valve and the pneumatic base valve. The system further includes a hydraulic output (230) configured to be fluidly coupled to a hydraulic braking system of a trailer, and a pneumatic output (318) configured to be fluidly coupled to a pneumatic braking system of a trailer. The hydraulic output is fluidly coupled to the outlet of the hydraulic base valve, and the pneumatic output is fluidly coupled to the outlet of the pneumatic base valve.