Propulsion Shift Management via Arbitrated Transmission Ratios
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Solution Overview
Problem
Current propulsion system control technologies face challenges in seamlessly transitioning between fuel economy and drivability modes, as model predictive control (MPC) may prioritize fuel efficiency over vehicle drivability, leading to suboptimal performance in certain driving conditions.
Innovation Solution
A control system architecture that includes a first control module for generating requested transmission ratios and a second control module to determine arbitrated ratios based on override inputs, allowing for prioritization of drivability by switching between MPC-determined and alternative transmission ratios within defined constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If model predictive control (MPC) is used to determine transmission ratio, then fuel economy is improved, but vehicle drivability deteriorates
Solution Approach 1:
The system dynamically switches between MPC control and alternative control modes based on driving conditions. The takeover module enables the system to transition from MPC-determined ratios to alternative ratios when drivability requirements arise, making the control system adaptable rather than fixed
Solution Approach 2:
The system changes the control parameter source based on operating conditions. When in takeover mode, the transmission ratio parameter switches from being MPC-determined to being alternatively determined, allowing optimization priorities to shift between fuel economy and drivability
2Use of energy by moving object
If transmission ratio is optimized for fuel economy, then energy efficiency is improved, but control flexibility deteriorates
Solution Approach 1:
The control system is segmented into two distinct modules: an MPC module for fuel economy optimization and an alternative control module for other priorities. This segmentation allows each module to specialize in its function while the takeover module coordinates between them, providing both optimization and flexibility
Solution Approach 2:
The takeover module acts as an intermediary between the MPC module and the alternative control module. It receives inputs from both sources and determines which transmission ratio to implement, providing the flexibility to switch between optimization goals without compromising either system
Data Source
AI summary
A propulsion system, control system, and method use model predictive control systems to generate a plurality of sets of possible command values and determine a cost for each set of possible command values. The set of possible command values that has the lowest cost is determined and defined as a selected set of command values. In some circumstances, the MPC-determined command value may be replaced by another transmission ratio command based on override inputs. Minimum and maximum transmission ratios are determined based on the override inputs, and a constrained (or arbitrated) transmission ratio is determined therefrom. The constrained or arbitrated transmission ratio is used to determine whether to apply an MPC-determined transmission ratio or a transmission ratio based on the arbitrated transmission ratio to determine an ultimate commanded transmission ratio. Pressure(s) are commanded to a transmission pulley assembly, which is configured to implement the ultimate commanded transmission ratio.