Blended Braking Torque Coordination in Powertrain Systems
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Solution Overview
Problem
Existing blended braking systems face challenges in efficiently coordinating friction braking and regenerative braking to effectively decelerate vehicles, particularly due to latency issues and limitations in communicating torque requests between control modules.
Innovation Solution
A method for operating a powertrain system that determines the regenerative braking capacity and generates simultaneous friction braking and regenerative braking torque requests, adjusting friction braking torque based on the difference between the total braking torque request and regenerative braking torque request, while ensuring torque security through a distributed control module system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If friction braking and regenerative braking are coordinated to decelerate the vehicle, then braking efficiency is improved, but system latency increases due to communication delays between control modules
Solution Approach 1:
The friction braking torque command is adjusted by an amount corresponding to the difference between the braking torque request and the regenerative braking torque request before the regenerative braking fully engages. This preliminary adjustment ensures immediate braking response while the regenerative braking capacity is determined and applied, eliminating the latency gap that would otherwise occur during torque coordination between the two braking systems.
2Loss of energy
If regenerative braking torque is maximized to increase electric power recovery, then energy efficiency is improved, but braking torque security may be compromised due to communication limitations between control modules
Solution Approach 1:
The control system continuously monitors the regenerative braking capacity determination and uses this feedback to adjust the friction braking torque command in real-time. The friction braking torque is adjusted by an amount corresponding to the difference between the total braking torque request and the regenerative braking torque request, ensuring that the total braking torque meets the operator's request while maximizing regenerative braking contribution and maintaining braking torque security despite communication limitations.
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 enables seamless coordination of friction and regenerative braking, maximizing electric power recovery and ensuring braking torque security by reducing system latency and accommodating changes in regenerative braking capacity, thus enhancing vehicle deceleration efficiency.
Implementation Method 1
The torque machine may transform vehicle kinetic energy that is transmitted through the drive wheels to energy that is storable in an energy storage device
Implementation Method 2
friction brake devices to generate friction braking torque
Data Source
AI summary
A method for operating a powertrain system including a torque machine coupled to a drive wheel of a vehicle includes determining a regenerative braking capacity of the powertrain system. In response to a net operator torque request including a braking torque request, a friction braking torque command to operate a friction brake system and a regenerative braking torque request for the torque machine are coincidentally generated, a torque command is generated for controlling operation of the torque machine in response to the regenerative braking torque request, and the friction braking torque command is adjusted by an amount corresponding to a difference between the braking torque request and the regenerative braking torque request.