Two-Stage Electro-Pneumatic Braking System for Multiaxle Vehicles
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Solution Overview
Problem
Conventional pneumatically controlled braking systems in multi-axle road vehicles cause discomfort to passengers due to abrupt braking, have long response times, and result in uneven wear of braking components, compromising passenger comfort and safety.
Innovation Solution
A two-stage electro-pneumatic braking system with a manual brake pedal having distinct operating stages for service and emergency braking, utilizing proportional solenoid valves controlled by a deceleration unit for precise and rapid braking, and incorporating electrodynamic braking to optimize comfort and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional pneumatically controlled braking system is used, then the braking force is sufficient to stop the vehicle quickly, but the braking is abrupt causing discomfort to passengers
Solution Approach 1:
The braking system dynamically adjusts the braking force based on the operating mode. In service braking mode, the system applies progressive and moderate braking force to ensure passenger comfort. In emergency braking mode, the system delivers maximum braking force for rapid stopping. This dynamic adaptation resolves the contradiction between quick stopping and passenger comfort.
Solution Approach 2:
The system changes the braking parameters (force intensity, application rate) depending on the selected mode. Service braking uses gradual parameter increase while emergency braking uses immediate maximum parameter application. This parameter variation allows the system to provide both comfort during normal operation and rapid stopping when needed.
2Reliability
If a conventional pneumatic braking system is used, then the system is reliable and safe, but the response time is long due to pneumatic propagation delay
Solution Approach 1:
The system replaces the purely mechanical/pneumatic control with an electro-pneumatic control system. Electrical signals are used to control pneumatic valves, providing much faster response time while maintaining the reliability of the pneumatic braking actuation. The electrical control signal propagates instantly to all axles, eliminating the pneumatic propagation delay.
Solution Approach 2:
An electronic control unit acts as an intermediary between the driver's braking input and the pneumatic braking system. The control unit receives the braking signal and immediately actuates the pneumatic valves at all axles simultaneously, bridging the gap between slow pneumatic response and the need for fast braking initiation.
3Force
If a conventional pneumatic braking system is used, then the system can provide strong braking force, but the wear of braking members is uneven and excessive
Solution Approach 1:
The system applies different braking forces to different axles based on local conditions and requirements. Each axle can have independently controlled braking intensity, allowing optimal force distribution that provides sufficient total braking force while minimizing unnecessary wear on individual braking components through precise local 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
The system provides progressive and moderate braking with reduced response time, minimizing passenger discomfort, optimizing dynamic behavior, and evenly distributing wear on braking components, ensuring enhanced comfort and safety.
Implementation Method 1
a proportional solenoid valve EVP for each braking module, receiving when the manual component is actuated an electric command and/or a pneumatic braking command, and the opening of which is proportional to the command(s) received
Implementation Method 2
pneumatic braking module connected to a reservoir for supplying gas for actuating the brakes
Data Source
Figure 1
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Figure 3
AI summary
The brake system (1) comprises the following sub-assemblies: a footbrake pedal (14) whose two stages correspond to service and emergency modes, respectively, pneumatic brake modules (6) which are assigned to each axle and each of which comprises a proportional solenoid valve EVP (9), at least one deceleration controlling UCD unit (12) which receives information from the pedal related to the position thereof and electrically controls the brake motor (31) and/or the EVP in the service and emergency modes, pneumatic control circuit which is actuatable in the emergency mode, only, and controls the EVP directly from the pneumatic box (19) of the pedal. Said invention is suitable for articulated multiaxel rod vehicles, in particular used for passenger transport.