Road-Aware Brake Battery Charge Control for Electric Truck Braking
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Solution Overview
Problem
Fully electric trucks face the risk of wheel brake fading due to insufficient battery resistance for motor braking, especially when fully charged, leading to reduced brake power and loss of speed control, particularly on long downhill slopes.
Innovation Solution
A computer system that controls the state of charge of a brake energy storage battery using road segment data, weight data, and other operational parameters to ensure sufficient resistance for motor braking, utilizing regenerative energy from the electrical propulsion motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the battery is fully charged to maximize energy storage, then the available energy for propulsion is improved, but the resistance for motor braking is reduced leading to brake fading
Solution Approach 1:
The battery system is segmented into two functional parts: a propulsion battery for energy storage and a brake energy storage battery for braking resistance. This segmentation allows the propulsion battery to be fully charged for maximum energy availability while the brake battery maintains sufficient charge for reliable motor braking, eliminating the trade-off between energy storage and braking reliability.
Solution Approach 2:
The brake energy storage battery acts as an intermediary between the propulsion motor and the wheel brakes. It absorbs regenerative energy during braking events and provides resistance during motor braking operations, mediating the interaction between the propulsion system and braking system to ensure both propulsion energy availability and braking reliability.
2Loss of energy
If regenerative braking is used to charge the battery, then energy recovery is improved, but the battery may become fully charged and lose braking resistance
Solution Approach 1:
The system incorporates feedback control through the control circuitry that continuously monitors the state of charge of the brake energy storage battery and adjusts regenerative braking operations accordingly. When the brake battery approaches full charge, the system modulates regenerative energy absorption to maintain sufficient braking resistance, ensuring that energy recovery does not compromise braking reliability.
Solution Approach 2:
The system dynamically changes operational parameters by switching between different braking modes (regenerative braking, motor braking, and friction braking) based on the state of charge of the brake energy storage battery. This parameter change allows the system to optimize energy recovery while maintaining adequate braking resistance by adjusting the mix of braking methods used.
3Speed
If wheel brakes are used continuously to control speed, then speed control is achieved, but brake fading occurs due to heat
Solution Approach 1:
The system replaces continuous mechanical friction braking with electrical motor braking for speed control. The motor braking system uses electromagnetic resistance from the propulsion motor (with support from the brake energy storage battery) to control vehicle speed, eliminating the need for continuous wheel brake engagement and the associated heat generation and brake fading.
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 ensures effective motor braking over long distances by optimizing the brake energy storage battery's capacity, reducing the risk of wheel brake fading and enhancing vehicle safety and efficiency.
Implementation Method 1
charging the brake energy storage battery with regenerative energy obtained from the electrical propulsion motor
Data Source
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AI summary
Present disclosure relates to a computer system comprising processing circuitry configured to obtain state of charge data from a brake energy storage battery of an electrically propelled vehicle, said vehicle comprising an electrical motor brake system for braking at least one electrical propulsion motor of said vehicle and charging the brake energy storage battery with regenerative energy obtained from the electrical propulsion motor, and cause control of the state of charge of the brake energy storage battery based on road segment data associated with a road segment ahead of the vehicle and the state of charge data.