Hybrid Powertrain Efficiency Optimization via Component Loss Mapping
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Solution Overview
Problem
Existing hybrid electric vehicle powertrains face inefficiencies in coordinating engine and motor/generator power sources to maximize total system efficiency, as previous control strategies do not adequately account for power losses in all components, leading to suboptimal performance and fuel economy.
Innovation Solution
A method that determines engine speed and torque to achieve maximum total powertrain efficiency by considering the efficiency of each subsystem, minimizing overall powertrain losses and ensuring balanced operation of engine, motor, and generator, through a strategy that filters engine speed and torque commands to manage power transitions effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine operates in its most efficient speed and torque operating region, then fuel economy is improved and emissions are reduced, but the total powertrain system efficiency may be compromised due to power losses in other components
Solution Approach 1:
The patent converts the harmful effect of power losses in components (generator, motor, transmission) into a beneficial control strategy by using a total system efficiency map that explicitly accounts for these losses. The controller uses this comprehensive efficiency information to make informed decisions about engine operating points, thereby converting what would be wasted energy considerations into an optimization opportunity for overall fuel economy.
Solution Approach 2:
The patent implements feedback by continuously monitoring actual engine speed and torque, comparing them against the optimal values determined from the total system efficiency map, and adjusting engine control parameters accordingly. This closed-loop control ensures the engine operates at or near the optimal efficiency point while accounting for dynamic changes in vehicle conditions and component efficiencies.
2Use of energy by moving object
If the engine size is reduced to improve fuel economy and emissions, then vehicle performance may be compromised due to limited power output
Solution Approach 1:
The patent applies multi-functionality by using the hybrid powertrain system to provide both engine power and motor/generator power to meet vehicle performance requirements. The controller dynamically coordinates between the two power sources, allowing a smaller engine to be paired with a motor that compensates for power deficiencies, thereby achieving both fuel economy improvement and maintained vehicle performance.
Solution Approach 2:
The motor/generator acts as an intermediary between the reduced-size engine and the vehicle drivetrain. It compensates for the limited power output of the smaller engine by providing additional power when needed and recovering energy during deceleration, thus bridging the gap between reduced engine size and maintained vehicle performance requirements.
3Loss of energy
If the controller optimizes for total system efficiency by considering all component losses, then the control strategy complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the total system efficiency map that accounts for all component power losses under various operating conditions. This pre-computed efficiency information is stored in lookup tables or maps that the controller can quickly reference during real-time operation, avoiding the need to perform complex real-time calculations while still achieving comprehensive system efficiency optimization.
Data Source
AI summary
A method is disclosed for managing power in a hybrid electric vehicle powertrain having multiple components, including an engine, a motor, a generator and a high voltage battery. Power losses in the individual components are computed. An engine speed corresponding to a minimum value for the power losses is selected to achieve optimal total powertrain efficiency.