Simulated EH Braking System for Work Machines
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Work machines with hydraulic braking systems face challenges in managing the interaction between hydraulic braking forces and engine braking forces, leading to unnatural deceleration and braking feel, especially for inexperienced operators, and existing expensive electro-hydraulic braking systems are costly due to redundancy requirements for fault tolerance.
Innovation Solution
A simulated electro-hydraulic braking system that combines hydraulic braking with power source braking, using a brake control valve, pressure reducing valve, and controller to adjust brake pressure and actuate the transmission for a natural braking feel without the need for costly redundancies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If engine braking force is added to hydraulic braking system, then braking efficiency is improved, but braking feel becomes unnatural for operator
Solution Approach 1:
The controller continuously monitors brake pedal position and transmission braking force, dynamically adjusting the hydraulic braking force in real-time to compensate for engine braking effects, thereby maintaining natural braking feel while preserving improved braking efficiency
Solution Approach 2:
The system dynamically changes the hydraulic braking force parameter based on transmission braking force and brake pedal position, reducing hydraulic braking when transmission provides significant engine braking to prevent over-deceleration and maintain natural operator feedback
2Reliability
If electro-hydraulic braking system with redundancy is implemented, then safety and reliability are improved, but system cost increases significantly
Solution Approach 1:
The transmission system performs dual functions: power transmission and braking force generation. This multi-functionality provides inherent redundancy for safety without requiring separate redundant braking systems, thereby maintaining high reliability while reducing overall system complexity and cost
Solution Approach 2:
The transmission automatically provides braking force through downshifting without requiring separate redundant braking components. The system uses its own operational characteristics (gear downshifting) to generate braking force, eliminating the need for expensive redundant electronic braking components
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 a natural braking feel while reducing brake wear and eliminating the need for expensive redundancy in electronic components, effectively integrating engine braking forces with hydraulic braking to manage deceleration and prolong brake component life.
Implementation Method 1
a pressure reducing valve output pressure at the second pressure reducing valve outlet increases from zero at the normally open position to a maximum bleed pressure at the maximum bleed position
Data Source
AI summary
Systems and methods for simulating electro-hydraulic (EH) braking of a work machine using a combination of hydraulic braking and engine braking may include determining a commanded brake pressure requested by an operator, determining an available engine braking force, and comparing the available engine braking force to a maximum available bleed pressure that is available to reduce a hydraulic braking force. An engine braking output and a pressure reducing valve output pressure may be determined based on the available engine braking force and the maximum available bleed pressure. A pressure reducing valve may be actuated so that the hydraulic braking force is equal to the commanded brake pressure minus the pressure reducing valve output pressure, and a transmission may be actuated so that the engine applies an engine braking force equivalent to the engine braking output to brake the work machine.