Heavy-Duty Vehicle Braking Power Split for Downhill Deceleration
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Solution Overview
Problem
Heavy-duty vehicles face challenges with brake fading due to prolonged use of friction brakes, especially when driving downhill, and existing regenerative braking systems lack sufficient torque and energy dissipation capabilities.
Innovation Solution
A braking arrangement that combines an electric machine, eddy current braking device, and a control unit to distribute regenerated electrical power between these components based on vehicle deceleration needs and energy absorption capabilities, allowing for optimized torque generation and energy management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If friction brakes are used for prolonged periods during downhill driving, then braking capability is maintained initially, but brake fading occurs due to heat build-up leading to significantly reduced braking capability
Solution Approach 1:
The patent replaces the mechanical friction braking system with an electrical braking system. The electric machine operates as a generator during braking, converting kinetic energy to electrical energy, which is then dissipated through a braking resistor. This substitution eliminates direct mechanical contact and friction, thereby preventing heat build-up on braking surfaces while maintaining reliable deceleration capability during prolonged downhill driving.
2Use of energy by moving object
If electrical machines are used for regenerative braking, then energy recovery is achieved, but braking torque capability is limited
Solution Approach 1:
The patent merges two braking mechanisms into a unified system: the electric machine provides regenerative braking torque while simultaneously generating electrical energy, and the eddy current brake provides additional electromagnetic braking torque. The control unit coordinates both devices to achieve sufficient total braking torque while maximizing energy recovery to the battery or capacitor storage system.
Solution Approach 2:
The electric machine serves multiple functions: it acts as a motor during acceleration, as a generator for regenerative braking, and its generated electrical energy is utilized both for energy recovery and for powering the eddy current brake. This multi-functionality allows the system to overcome the limited braking torque of the electric machine alone.
3Use of energy by moving object
If energy absorption device is used to store regenerated electrical energy, then energy recovery efficiency is improved, but energy absorption capability is limited
Solution Approach 1:
The patent introduces a braking resistor as an intermediary component that dissipates excess electrical energy as heat through controlled resistance. The control unit manages power distribution between the energy storage device (battery/capacitor) and the braking resistor, directing surplus energy that exceeds the storage device's absorption capability to the resistor, thereby preventing energy loss while maintaining system stability.
4Force
If combination of electric machine and eddy current brake is used, then braking torque is enhanced, but device complexity increases
Solution Approach 1:
The electric machine serves dual purposes: providing regenerative braking torque and powering the eddy current brake through generated electrical energy. This multi-functionality reduces the need for separate energy sources for each braking device, thereby mitigating the increase in system complexity while achieving enhanced total braking torque through the combination of both devices.
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 enhanced braking torque, reduces the risk of brake fading, and optimizes energy usage, enabling efficient downhill driving and emergency braking without relying on additional friction brakes.
Implementation Method 1
The electric machine then acts as a generator which converts the kinetic energy from the vehicle into electrical energy
Implementation Method 2
an eddy current braking device (240, 290)
Data Source
AI summary
A braking arrangement for decelerating a heavy duty vehicle, the arrangement including a control unit, at least one electric machine arranged for regenerative braking, an electrical energy absorption device, an eddy current braking device, and a power distribution network arranged to connect the electric machine to the energy absorption device and to the eddy current braking device, wherein the control unit is configured to distribute regenerated electrical power from the electric machine between the energy absorption device and the eddy current braking device by the power distribution network in dependence of a target deceleration value of the heavy duty vehicle.