Fuel Cell Auxiliary Power Unit with Switchable Alternator
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Solution Overview
Problem
Current vehicle power systems rely on engine-driven alternators, which are inefficient and generate significant fuel penalties, and diesel APUs, which require maintenance and produce emissions, noise, and vibrations, making them undesirable for auxiliary power.
Innovation Solution
A vehicle power system that incorporates a fuel cell capable of shifting between multiple modes based on operating and environmental conditions, using a solid oxide fuel cell and a switchable alternator to optimize energy production and distribution, with a controller managing the alternator and fuel cell operations to minimize fuel consumption and emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an engine-driven alternator is used to provide electrical power, then electrical energy can be generated, but fuel efficiency deteriorates due to continuous operation and conversion losses
Solution Approach 1:
The alternator is made selectively operable rather than continuously driven, allowing it to be engaged only when needed for electrical power generation. This dynamic operation eliminates the continuous energy loss associated with always-coupled alternators while maintaining the capability to generate electrical power when required.
Solution Approach 2:
The alternator is extracted from the continuous engine-driven configuration and made independently selectable. By decoupling the alternator from mandatory engine operation, the system can choose to operate the alternator only when the fuel cell cannot meet electrical demands, thereby reducing overall energy conversion losses.
2Power
If a diesel engine APU is used for auxiliary power, then electrical requirements can be met, but emissions and noise increase
Solution Approach 1:
The diesel engine APU is replaced with a fuel cell-based auxiliary power system. The fuel cell uses electrochemical conversion of fuel to electricity, eliminating the combustion process that generates emissions and noise. This substitution maintains the required electrical power output while removing harmful byproducts.
3Reliability
If the alternator is continuously coupled to the engine, then electrical power is always available, but system complexity increases
Solution Approach 1:
The alternator coupling is made dynamic and selectable rather than fixed. The system can selectively engage or disengage the alternator from the engine based on power demands and fuel cell performance, reducing mechanical complexity while ensuring electrical power is available when needed through coordinated operation of the fuel cell and alternator.
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 enhances fuel efficiency by selectively using the fuel cell or alternator based on energy storage state and load demands, reducing emissions and noise, and improving driver comfort by minimizing vibrations and maintenance needs.
Implementation Method 1
a fuel cell having a plurality of fuel cell modes comprising a Power Mode wherein the fuel cell converts fuel into electrical energy
Implementation Method 2
an alternator comprising a first power mode wherein the alternator is driven by the engine to convert mechanical energy from the engine into electrical energy
Data Source
AI summary
A power distribution system comprises at least one fuel cell that is selectively operated in response to conditions to provide power to electrical loads and/or to charge an electrical storage device such as a vehicle battery. One form of an alternator can be selectively engaged or disengaged to provide power to the electrical loads and/or to charge the electrical storage device. Either or both of the fuel cell and alternator can be operated to provide electrical power.