Regenerative Braking Torque Threshold Control for Loaded EVs
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Solution Overview
Problem
Existing electrified vehicles face limitations in energy recovery efficiency, particularly when carrying increased loads or towing trailers, as their energy recovery thresholds are not dynamically adjusted, leading to suboptimal regenerative braking and potential brake degradation, noise, and vibrations.
Innovation Solution
An electrified vehicle equipped with an energy recovery mechanism and a controller that selectively increases the negative wheel torque threshold based on the vehicle's mass, including estimating effective mass through load sensors and deceleration comparison, allowing for enhanced regenerative braking without unwanted noise or vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the negative wheel torque threshold is increased to improve energy recovery efficiency, then energy recovery efficiency improves, but noise and vibrations increase
Solution Approach 1:
The patent applies dynamics by making the negative wheel torque threshold adjustable rather than fixed. The controller dynamically modifies the threshold based on detected vehicle conditions (such as deceleration rate, driver input, and road conditions), allowing the system to optimize energy recovery while preventing excessive torque that would cause noise and vibrations. This dynamic adjustment resolves the contradiction by adapting the torque threshold to real-time operating conditions.
Solution Approach 2:
The patent changes the parameter of the negative wheel torque threshold from a constant value to a variable value that depends on multiple operating parameters. By monitoring factors such as vehicle deceleration rate, driver brake input, and road surface conditions, the system adjusts the torque threshold parameter to maximize energy recovery without exceeding levels that generate harmful noise and vibrations.
2Loss of energy
If the negative wheel torque threshold is increased to recover more energy, then energy recovery efficiency improves, but brake degradation increases
Solution Approach 1:
The patent implements feedback control by continuously monitoring vehicle deceleration rates and comparing them against threshold values. The controller uses this feedback to determine when to apply regenerative braking and when to rely on friction brakes, optimizing the balance between energy recovery and brake preservation. The system learns from operational patterns and adjusts torque application to minimize friction brake wear while maintaining safe stopping capability.
3Loss of energy
If the negative wheel torque is applied to recover energy, then energy recovery improves, but vehicle stability deteriorates
Solution Approach 1:
The patent changes the torque application parameters based on detected vehicle stability conditions. By monitoring deceleration rates, wheel slip, and vehicle dynamics, the system adjusts the negative wheel torque magnitude and distribution across different wheels. This parameter adaptation allows energy recovery while maintaining vehicle stability, particularly during cornering, low-traction conditions, or when rapid deceleration is detected.
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 solution enhances energy recovery efficiency, reduces brake degradation, maintains stability, and improves fuel economy by dynamically adjusting the energy recovery threshold according to the vehicle's mass, including loads and trailers.
Implementation Method 1
energy recovery mechanism configured to apply a negative wheel torque up to a negative wheel torque threshold
Implementation Method 2
the controller is configured to estimate the effective mass of the electrified vehicle by comparing a negative wheel torque level to a level of deceleration of the electrified vehicle
Data Source
AI summary
This disclosure relates to an electrified vehicle configured to selectively increase an energy recovery threshold and a corresponding method. In particular, an example electrified vehicle includes an energy recovery mechanism configured to apply a negative wheel torque up to a negative wheel torque threshold. The electrified vehicle also includes a controller configured to selectively increase the negative wheel torque threshold based on a mass of the electrified vehicle.