EV Waste Heat Recovery Using a Combi-Generator Cycle
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Solution Overview
Problem
Current electric vehicles do not effectively recover thermal energy generated as waste heat, which is typically lost as inefficiency, despite the potential for energy recovery being substantial due to the power and efficiency of their drives.
Innovation Solution
An electromechanical energy recovery system that converts waste heat from electrical machines and energy accumulators into mechanical and electrical energy using a combi-generator, which combines a gas-operated mechanical linear motor with an electrical machine, utilizing a working medium with a low boiling point to generate pressure for energy recovery, and includes a gas expansion turbine to provide additional mechanical or electrical energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If waste heat is dissipated to surroundings, then thermal management is simplified, but energy efficiency deteriorates
Solution Approach 1:
The patent converts waste heat, which is normally dissipated as harmful loss, into useful mechanical and electrical energy through the combi-generator system. The thermal energy from electrical machines and energy accumulators is recovered and transformed into drive torque and electrical energy, turning the harmful waste heat into a beneficial resource for vehicle propulsion.
Solution Approach 2:
The patent merges a mechanical linear motor and an electrical machine into a single combi-generator unit. The mechanical motor utilizes waste heat to generate linear motion, which is then converted to rotary motion to drive the electrical machine, combining two energy conversion mechanisms into one integrated system that recovers both mechanical and electrical energy from thermal sources.
2Use of energy by moving object
If thermal energy is converted to mechanical and electrical energy, then energy efficiency is improved, but device complexity increases
Solution Approach 1:
The combi-generator is designed as a multi-functional device that simultaneously performs mechanical work generation and electrical energy generation from a single thermal input source. The system can operate in different modes depending on vehicle requirements, providing both direct mechanical drive torque and electrical energy to the powertrain, thereby maximizing the utility of recovered waste heat.
3Power
If a working medium with low boiling point is used, then evaporation and pressure generation are enhanced, but system reliability may deteriorate
Solution Approach 1:
The patent utilizes phase transitions of the working medium, specifically evaporation from liquid to gas phase, to generate high pressure for driving the mechanical linear motor. The low boiling point of the working medium enables rapid evaporation at relatively low temperatures, creating the pressure differential needed for efficient energy recovery while the closed-loop system maintains reliability through controlled phase changes.
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
Enhances energy efficiency by utilizing waste heat to generate additional torque for vehicle driving or electrical energy recovery, supporting the vehicle's drive and economizing electrical energy through the conversion of thermal energy into mechanical and electrical forms.
Implementation Method 1
By evaporation of a working medium with low boiling point and high vapor pressure, it is possible to build up a pressure potential relative to the surroundings
Implementation Method 2
the waste heat of at least one electrical machine and/or at least one energy accumulator of the electric vehicle is converted into mechanical energy
Implementation Method 3
The gaseous working medium is utilized in the combi-generator to perform mechanical work and/or to generate electrical current
Implementation Method 4
After the expansion work in the combi-generator, the working medium is again condensed in a condenser and taken back to the evaporator
Data Source
AI summary
A vehicle may include an electromechanical energy recovery system and be configured to perform a method for its operation.