Hybrid Power Management Dynamic SOC Trajectory
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Solution Overview
Problem
Current methods for managing the state of charge (SOC) of energy storage devices in hybrid electric vehicles (HEVs) lead to decreased battery life and fuel economy, as they do not effectively regulate energy usage within a defined SOC window, often requiring the combustion engine to recharge the battery when it drops below a certain threshold.
Innovation Solution
A system and method that determines the SOC of an energy storage device, calculates a reference SOC, and adjusts torque apportionment between the motor and engine based on an error, using regenerative braking to charge the battery and optimize energy usage, thereby extending battery life and improving fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the SOC is controlled by a usage window with upper and lower SOC values, then the ESD can provide power for the motor, but the life of the ESD decreases and fuel economy performance decreases
Solution Approach 1:
The patent changes the control parameters from simple upper/lower SOC thresholds to a dynamic reference SOC trajectory that adapts to driving conditions. The controller continuously adjusts the reference SOC based on monitored operating parameters (vehicle speed, acceleration, load, temperature), transforming the control strategy from static to dynamic, thereby optimizing both ESD utilization and its longevity.
Solution Approach 2:
The patent implements feedback control by continuously monitoring operating parameters and adjusting the reference SOC and torque apportionment accordingly. The controller compares actual SOC with reference SOC and dynamically adjusts torque distribution between motor and engine to maintain optimal SOC levels, preventing excessive discharge that would harm ESD life while maximizing fuel economy.
2Quantity of substance
If the engine recharges the ESD when SOC drops below the lower SOC value, then the ESD can be recharged, but the life of the ESD decreases and fuel economy decreases
Solution Approach 1:
The patent performs preliminary action by maintaining SOC above the reference trajectory through proactive torque apportionment adjustments before SOC drops to critical levels. By continuously adapting reference SOC and torque distribution based on predicted driving conditions, the system prevents deep discharge cycles that would require aggressive engine recharging, thereby extending ESD life while improving fuel economy.
3Loss of energy
If regenerative braking is used to charge the ESD, then recaptured energy can be stored, but unregulated usage can lead to excessive SOC fluctuations
Solution Approach 1:
The patent implements feedback control by continuously monitoring operating parameters and adjusting the reference SOC and torque apportionment accordingly. The controller compares actual SOC with reference SOC and dynamically adjusts torque distribution between motor and engine to maintain optimal SOC levels, preventing excessive discharge that would harm ESD life while maximizing fuel economy.
Solution Approach 2:
The patent transforms the static SOC threshold control into a dynamic reference SOC trajectory that adapts to real-time driving conditions. The reference SOC and torque apportionment are continuously adjusted based on monitored parameters (vehicle speed, acceleration, load, temperature), enabling the system to smoothly manage regenerative energy capture and maintain SOC stability across varying operational scenarios.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach extends the life of the energy storage device and enhances fuel economy by utilizing recaptured energy for propulsion, ensuring the battery remains within a predetermined SOC range while optimizing torque distribution between the motor and engine.
Implementation Method 1
The energy storage device is charged using regenerative braking. This increases the state of charge for the energy storage device.
Data Source
AI summary
A system, computer readable storage device and method for controlling torque in a hybrid electric vehicle. The method comprises determining a state of charge of an energy storage device, obtaining a reference state of charge, obtaining an error from a difference between the determined state of charge and the reference state of charge; and apportioning torque between a motor and an engine based upon the error. The motor is electrically coupled to the energy storage device and powered by the energy storage device. A state of charge (SOC) correction factor is determined based upon the error. The SOC correction factor is used to adjust a torque ratio of motor to engine torque that is determined for a given torque command.