Axle Drive Regeneration Switching for Excess Brake Energy Recovery
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Solution Overview
Problem
In battery electric vehicles and hybrid electric vehicles, excess brake energy is often lost during regenerative braking due to the limited regenerating capacity of the connected axle drive unit, leading to inefficiencies in energy recovery.
Innovation Solution
The method involves switching a second axle drive unit to regeneration mode when the potential brake energy exceeds a threshold based on the regenerating capacity of the first axle drive unit and the connecting energy required, allowing both units to regenerate brake energy and improve overall energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a single axle drive unit is used for regenerative braking, then the device complexity is reduced, but the energy recovery capacity is limited and excess brake energy is lost
Solution Approach 1:
The patent combines multiple axle drive units (first and second axle drive units) to work together for regenerative braking. When the potential brake energy exceeds the threshold, both axle drive units are activated to recover energy, merging their regenerative capacities to handle excess energy that a single unit cannot process alone.
Solution Approach 2:
The axle drive units are designed with multi-functionality, serving both as propulsion systems and as regenerative braking systems. The control unit dynamically switches between propulsion mode and regeneration mode, allowing the same hardware to perform multiple functions based on operational conditions.
2Loss of energy
If the regenerating capacity of the axle drive unit is increased, then more brake energy can be recovered, but the device complexity and cost increase
Solution Approach 1:
The system dynamically adjusts the regenerative braking configuration based on real-time conditions. The control unit monitors the potential brake energy and dynamically switches between using a single axle drive unit and using both axle drive units, optimizing energy recovery without requiring permanently oversized components.
Solution Approach 2:
The patent changes the operational parameters of the axle drive units by switching between different regeneration modes. When energy recovery demand is low, only one unit operates in regeneration mode; when demand exceeds the threshold, both units are activated, effectively changing the system's regenerative capacity parameter based on conditions.
3Loss of energy
If both axle drive units are always connected for regeneration, then maximum energy recovery is achieved, but the connecting energy and operational complexity increase
Solution Approach 1:
Instead of always connecting both axle drive units for regeneration, the system applies partial action by activating only the necessary number of units based on the potential brake energy threshold. This avoids the excessive energy consumption and complexity of maintaining both units permanently connected when full capacity is not needed.
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
This approach enhances energy efficiency by ensuring that excess brake energy is recovered, thereby increasing the vehicle's driving potential and sustainability by utilizing both axle drive units effectively during braking events.
Implementation Method 1
During regenerative braking, an electric motor acts as an electric generator and converts mechanical energy into electrical energy, which is fed into the battery system
Implementation Method 2
a brake disc on a wheel, which produces friction to slow or stop the vehicle. A friction energy generated during braking is converted into a heat energy
Data Source
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AI summary
The present disclosure relates to a method for braking a vehicle, a vehicle comprising a control unit configured to perform such a method and a computer program element for braking a vehicle. The method for braking a vehicle comprises estimating a potential brake energy to be regenerated during a braking event, determining a threshold based on a regenerating capacity of a first axle drive unit, comparing the potential brake energy to be regenerated with the threshold, and switching a second axle drive unit to a regeneration mode for regenerating the brake energy in case the potential brake energy to be regenerated is higher than the threshold.