Hydraulic Return Valve Braking When Regeneration Saturates
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Solution Overview
Problem
Regenerative hydraulic transmission systems face challenges in providing a reliable transmission retention function, especially when batteries or accumulators are fully charged, leading to a loss of restraint function during prolonged braking or descending situations.
Innovation Solution
A hydraulic transmission system with a primary motor and a second hydraulic device forming a circuit with a supply and return line, featuring a return valve controlled by a control system to manage pressure and exert restraint on the vehicle component, ensuring a consistent braking or deceleration effect through energy dissipation in the return line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative braking is used to recharge batteries or accumulators during braking phases, then energy recovery is improved, but the restraint function is lost when batteries or accumulators are fully charged
Solution Approach 1:
The braking system is segmented into two independent parts: a regenerative braking system for energy recovery and a friction braking system for reliable restraint. This segmentation allows each system to operate independently, ensuring that when regenerative braking cannot provide sufficient restraint (when batteries are full), the friction braking system can take over without being affected by the limitations of the regenerative system.
Solution Approach 2:
A control unit acts as an intermediary between the regenerative braking system and the friction braking system. This intermediary coordinates the operation of both systems, managing energy recovery while ensuring reliable restraint function is maintained through appropriate activation of the friction braking system when needed.
2Reliability
If friction braking is used for engine braking, then restraint function is maintained, but significant energy losses occur
Solution Approach 1:
The system merges regenerative braking and friction braking into a unified braking system. The control unit intelligently combines both braking mechanisms, using regenerative braking for energy recovery when possible and supplementing with friction braking when additional restraint is needed, thereby achieving both energy efficiency and reliable restraint function.
3Loss of energy
If regenerative braking is used during long descents, then energy recovery is improved, but the restraint function deteriorates when accumulators are charged
Solution Approach 1:
The friction braking system is prepared in advance as a backup restraint mechanism. When regenerative braking approaches its energy storage limits during long descents, the control unit preemptively activates the friction braking system to maintain adequate restraint capability, preventing the situation where restraint function is lost due to full accumulators.
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 maintains a consistent braking or deceleration effect even when batteries or accumulators are fully charged, preventing damage and ensuring vehicle control by generating a pressure rise in the return line, thus addressing the limitations of regenerative systems.
Implementation Method 1
the primary motor exerts a restraint function on the rotation of the vehicle component by increasing the pressure in the return line
Implementation Method 2
a hydraulic transmission system comprising a first hydraulic device adapted to be driven in rotation by a primary motor, a second hydraulic device adapted to drive in rotation a vehicle component, the first hydraulic device and the second hydraulic device defining a hydraulic circuit
Data Source
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AI summary
A hydraulic transmission system comprising a first hydraulic device (10) designed to be driven to rotate by a primary motor (12), a second hydraulic device (20) designed to drive a vehicle component (22) to rotate, the first hydraulic device (10) and the second hydraulic device (20) defining a hydraulic circuit (30) comprising a supply line (32) and a return line (34), the system being characterized in that it comprises a return valve (60) positioned on the return line (34), the return valve (60) being configured so as to define a variable restriction in the return line (34), the return valve (60) being controlled by a control (64) and being configured to selectively form a restriction on the return line (34).