LNG-Lithium Hybrid Vehicle Powertrain Architecture
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Solution Overview
Problem
Current hybrid vehicles face limitations in maximizing cruising distance and efficiency due to reliance on less efficient fossil fuels and battery technologies, particularly in reducing oil dependence and environmental impact.
Innovation Solution
The design of a hybrid vehicle that combines liquid natural gas as a fuel source with advanced lithium-ion batteries, utilizing an electric series motor for acceleration and an electric shunt motor for cruising, along with a control system to optimize power routing between the LNG engine and lithium-ion batteries for efficient energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If lithium-ion batteries are used instead of NiMH batteries, then weight is reduced and storage capacity is improved, but device complexity increases due to advanced battery management requirements
Solution Approach 1:
The patent combines the LNG engine generator system with the lithium-ion battery system into a hybrid powertrain, where the LNG engine serves as both a propulsion source and a charging generator. This merging allows the system to leverage the high energy density of LNG while using the lightweight lithium-ion batteries for energy storage and motor propulsion, resolving the weight-complexity tradeoff by integrating multiple energy sources into a unified hybrid architecture
2Quantity of substance
If compressed natural gas is used as fuel, then storage capacity is reduced, but device complexity increases due to higher compression requirements and larger storage space
Solution Approach 1:
The patent changes the physical state parameter of natural gas from compressed gas to liquid form. By storing natural gas in liquid form at cryogenic temperatures, the system achieves significantly higher volumetric energy density (42% higher than compressed natural gas) while using a dedicated cryogenic storage system, thereby improving fuel quantity without proportionally increasing system complexity
3Quantity of substance
If LNG is stored at cryogenic temperatures, then energy density is improved, but loss of energy increases due to cooling and insulation requirements
Solution Approach 1:
The patent implements a self-service cooling system where the LNG storage tank uses its own evaporated gas (boil-off gas) to cool incoming liquid LNG during refilling operations. This self-cooling mechanism reduces the need for external refrigeration power, minimizing energy losses while maintaining the cryogenic temperatures necessary for high energy density storage
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 combination enhances cruising distance and efficiency, reducing oil dependence and environmental impact by leveraging the advantages of LNG and lithium-ion batteries, providing a more environmentally friendly and efficient propulsion system.
Implementation Method 1
liquid natural gas which is stored at −160 degrees C. (−260 degrees F.)
Data Source
AI summary
The invention of the LNG-Lithium Hybrid Vehicle (LLHV) combines Liquid Natural Gas (LNG) and lithium-ion battery power sources to propel the vehicle, said vehicle having an electric series motor for acceleration and a shunt motor for cruising. An accelerator engaging arm is attached to the primary acceleration pedal for the purpose of operating the series motor and the shunt motor. The invention further provides an LNG control system that routes power from the generator to either run the vehicle or recharge the lithium-ion batteries.