Hybrid Powertrain Engine Operating Point Selection
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Solution Overview
Problem
Current hybrid powertrain systems face challenges in optimizing engine operation to balance operator power requests with energy storage device state of charge, leading to inefficiencies in fuel economy and battery charging.
Innovation Solution
A method that monitors operator power requests and energy storage device state of charge to determine the most cost-effective engine operating points, allowing the engine and electric machine to communicate tractive power through a transmission device, optimizing torque and rotational speed control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the engine operates to meet operator power requests, then power delivery is improved, but fuel economy deteriorates
Solution Approach 1:
The system dynamically adjusts engine operating points based on real-time conditions including operator power requests and battery state of charge. The control system continuously optimizes the balance between engine power output and fuel consumption by selecting from multiple candidate operating points, allowing the system to adapt to varying driving conditions and energy storage levels.
Solution Approach 2:
The method evaluates multiple candidate engine operating points with different parameters (torque, speed, fuel consumption) and selects the optimal operating point based on current system state. By changing engine operating parameters dynamically rather than maintaining fixed settings, the system achieves both adequate power delivery and improved fuel economy.
2Power
If the engine operates at high power output, then operator power requests are met, but battery charging efficiency deteriorates
Solution Approach 1:
The control system proactively manages battery charge levels by evaluating candidate operating points that consider future charging needs. Before battery charge becomes critical, the system selects operating points that optimize both power delivery and battery charging, preventing energy depletion and ensuring sustained operation.
Solution Approach 2:
The system continuously monitors battery state of charge and uses this feedback to adjust engine operating point selection. When battery charge levels change, the control system re-evaluates candidate operating points to maintain optimal balance between meeting power requests and maintaining battery charging efficiency, creating a closed-loop control system.
Data Source
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AI summary
An engine (14) and an electric machine (56,72) are operative to communicate tractive power with a transmission device (10) to control output power to an output member (64). The electric machine (56,72) is electrically coupled to an energy storage device (74). A method for controlling the engine (14) and electric machine (56,72) includes monitoring an operator request for power, monitoring a state of charge of the energy storage device (74), determining an operating cost for each of a plurality of candidate engine operating points based on the operator request for power and the state of charge of the energy storage device (74); and operating the engine (14) at the candidate engine operating point having a preferred operating cost.