Hybrid Powertrain Control Architecture for Input Speed Torque Optimization
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Solution Overview
Problem
Powertrain systems with electro-mechanical transmissions face challenges in optimizing operating conditions for continuously variable mode operation, particularly in determining preferred engine inputs and motor torques to minimize costs related to fuel economy, emissions, and battery life while meeting operator torque requests.
Innovation Solution
A method and apparatus that determine a range of engine inputs and motor torques for a powertrain system comprising an internal combustion engine and two electrical machines, calculating costs for different operating conditions to identify a preferred engine input that optimizes system efficiency and operation in continuously variable mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the powertrain system operates in continuously variable mode with multiple torque-generative devices, then the system can provide flexible torque control and improved efficiency, but the complexity of determining optimal operating conditions increases significantly
Solution Approach 1:
The patent segments the continuously variable operating range into multiple discrete operating range states. For each state, the system determines a preferred operating condition independently through cost function evaluation. This segmentation transforms the complex continuous optimization problem into multiple simpler discrete decisions, reducing control complexity while maintaining adaptability across the full operating range.
Solution Approach 2:
The system dynamically transitions between different operating range states based on real-time operating conditions. The preferred operating condition for each state is determined through dynamic cost function evaluation that considers fuel economy, emissions, and battery life. This dynamic approach allows the system to adapt to changing conditions while using a structured methodology to manage complexity.
2Loss of energy
If the system evaluates multiple operating range states with cost functions, then fuel economy and emissions are optimized, but the computational burden and control processing time increase
Solution Approach 1:
The patent pre-establishes cost functions for each operating range state that encapsulate fuel economy, emissions, and battery life considerations. These cost functions are prepared in advance and can be evaluated quickly during real-time operation. By structuring the optimization criteria beforehand, the system reduces computational burden during actual control decisions while maintaining comprehensive optimization of energy loss factors.
3Productivity
If the system uses multiple torque-generative devices including electrical machines, then system efficiency and torque delivery are improved, but the difficulty of coordinating device operation and managing energy flow increases
Solution Approach 1:
The patent introduces a supervisory controller that acts as an intermediary between the multiple torque-generative devices (internal combustion engine and electrical machines). This supervisory controller determines the preferred operating conditions for each device based on cost function evaluation and coordinates their operation accordingly. The intermediary controller manages the complexity of coordinating multiple devices while maximizing torque delivery efficiency and system productivity.
Data Source
AI summary
There is provided a control system for a powertrain system including an electro-mechanical transmission that is selectively operative in a plurality of fixed gear modes and continuously variable modes. The control system is adapted to execute the following steps, comprising determining a range of permissible engine input speeds and a range of permissible engine input torques, and determining motor input torques for the first and second electrical machines based upon the range of permissible engine input speeds and the range of permissible engine input torques. A cost is determined for each of the motor input torques. A preferred engine input speed and a preferred engine input torque are identified based upon the costs for the motor input torques.