Hybrid Powertrain Three-Mode Depletion Strategy
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Solution Overview
Problem
Hybrid electric vehicles face challenges in sizing their energy storage systems due to variations in battery pack voltage and resistance, leading to increased power and energy requirements, which can result in larger, heavier, and more costly batteries, limiting their electric-only range and efficiency.
Innovation Solution
A hybrid powertrain system with a control system that operates in three modes: electric-only, charge-depleting, and charge-sustaining, allowing the engine to be used strategically to maintain energy reserves and reduce battery power requirements, enabling the use of energy-dense batteries while maintaining consistent performance across varying temperatures and states-of-charge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ESS is sized to meet power requirements at minimum state-of-charge and lowest temperature, then electric-only drive performance is maintained, but ESS mass, volume, and cost increase
Solution Approach 1:
The system dynamically adjusts operating modes between electric-only, charge-depleting hybrid, and charge-sustaining hybrid based on real-time conditions including state-of-charge and temperature, allowing the ESS to operate below its maximum rated capacity while maintaining performance when needed
Solution Approach 2:
The control system monitors and responds to changes in temperature and state-of-charge parameters, adjusting power distribution and engine operation to maintain electric-only drive performance at minimum conditions without requiring the ESS to be sized for all extreme conditions simultaneously
2Duration of action of moving object
If energy dense batteries are used to increase electric-only operating range, then electric-only range is improved, but voltage variation and resistance increase
Solution Approach 1:
The control system continuously monitors state-of-charge and temperature to compensate for voltage variation and resistance changes in energy dense batteries, adjusting power management strategies to maintain consistent power capability across the discharge cycle
Solution Approach 2:
The system proactively manages state-of-charge levels and engages the engine before power capability becomes insufficient, preventing performance degradation rather than reacting to it
3Power
If the engine is used to maintain energy reserve in charge-sustaining mode, then battery power requirements are reduced, but engine use increases
Solution Approach 1:
The engine operates partially in charge-sustaining mode to maintain energy reserve rather than continuously, engaging only when needed to recharge the ESS and disengaging when electric power suffices, reducing overall engine use compared to conventional hybrids
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
The system achieves similar electric-only drive behavior and range as extended-range electric vehicles while reducing energy storage system power requirements, potentially lowering costs, mass, and volume, and enabling the use of higher energy content cells, ensuring consistent performance.
Implementation Method 1
The ESS is typically a battery or battery pack for a hybrid electric vehicle
Implementation Method 2
An extended-range electric vehicle is a hybrid electric vehicle that is designed to provide consistent electric-only drive performance
Data Source
AI summary
A hybrid powertrain for propelling a vehicle includes an engine and an energy storage system operatively connected to the engine. Both the engine and the energy storage system are operable for providing power to propel the vehicle. A control system is operatively connected to the engine and the energy storage system and is configured to execute a stored algorithm that determines required energy reserve, remaining energy, and power capability of the energy storage system. The control system commands operation in one of a first operating mode, a second operating mode, and a third operating mode based on the required energy reserve, the remaining energy, and the power capability of the energy storage system.