Hybrid Powertrain Traction Control via Torque Limit Coordination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional powertrains face challenges in effectively managing torque to prevent wheel slip during traction loss, particularly in hybrid electric vehicles where torque output is influenced by battery power limits, temperature, and operational states, leading to inefficiencies in traction control.
Innovation Solution
A method is implemented to control an automotive powertrain by setting a propulsive torque limit when traction loss is detected, coordinating engine and electric machine operation to ensure the engine is stopped or restarted based on torque limits, and supplementing machine torque with engine torque to maintain propulsive efficiency, with the engine operating as a generator to enhance torque delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric machine is used for traction control with high control bandwidth and accuracy, then wheel slip is reduced and traction control is improved, but the engine and brakes become less utilized and coordination complexity increases
Solution Approach 1:
The patent merges the traction control functions of the engine, electric machine, and brakes into a unified control system. The controller coordinates these three components to work together, with the electric machine playing a primary role while the engine and brakes provide supplementary support, thereby achieving effective traction control without over-relying on a single component.
Solution Approach 2:
The electric machine is designed to perform multiple functions: it serves as the primary traction control actuator, can supplement the engine when needed, and works in coordination with the brake system. This multi-functionality allows the system to maintain simplicity while achieving reliable traction control across various operating conditions.
2Measurement precision
If the engine is stopped when machine torque limit exceeds propulsive limit, then traction control precision is improved, but response time may be delayed due to engine restart requirements
Solution Approach 1:
The controller predicts future machine torque limits based on current operating conditions and proactively manages engine state transitions. By anticipating when the engine will be needed again, the system can prepare for restarts or maintain idle states that minimize response delays while preserving torque control precision during traction control events.
Solution Approach 2:
The system dynamically adjusts the engine stop/start strategy based on real-time conditions including predicted torque requirements, battery state of charge, and current traction control needs. This dynamic approach allows the controller to optimize the balance between torque precision and response time by adapting engine management decisions to changing operational contexts.
3Power
If the engine operates as a generator to supplement machine torque, then propulsive torque limit is met, but energy efficiency may be reduced due to generator operation
Solution Approach 1:
The engine operates as a generator only partially, supplementing the electric machine's torque output only when necessary to meet the propulsive torque limit. The controller carefully manages the degree of engine participation, using generator mode just enough to bridge the gap between available electric machine torque and required propulsive torque, thereby minimizing energy efficiency losses while ensuring adequate power delivery.
Solution Approach 2:
The system changes operational parameters dynamically, switching between different engine modes (off, generator, direct drive) based on real-time torque requirements, battery state of charge, and efficiency considerations. By adjusting these parameters optimally, the system maximizes propulsive torque when needed while minimizing the negative impact on energy efficiency during generator operation.
Data Source
AI summary
An electric machine and internal combustion engine are coordinated to provide traction control for an automotive vehicle. A propulsive torque limit is set by a controller during a loss of traction. When the machine torque limit is greater than the propulsive torque limit, the engine is pulled down. When the machine torque is less than the propulsive torque limit, the engine is pulled up. The controller coordinates the pulled up engine with the machine such that the engine is subordinated to the machine.