APU = auxiliary power unit

Aircraft engines Ceramic turbine nozzles in the APU (Auxiliary Power Unit Engine). Seals runners installed in different business jets such as Falcon, Citation and Learjet. Ceramic oil pump spacer enhance engine could start capability on APUs on Boeing 777 and 737 and all Airbuses. Cutter pins, which are used as a safety feature for air turbine starters. Ceramic wear indicator on Airbus APU starter brushes since 1997... 

Key SPC = standard performance capability, HPC = high-performance capabihty, STD = standard, Cl = corrosion inhibited, HTS = high thermal stability, TP = turbo-prop, TJ = turbo-jet, TF = turbo-fan, APU = auxiliary power unit... 

AIP American Institute of Polymers APU auxiliary power unit... 

In combination with fossil fuels, a fuel processor converts the hydrocarbon fuel into synthesis gas, using one of the technologies as described in the section Industrial Processes for Syngas Production, albeit at a much smaller capacity, for example, in the application for microCHP, using natural gas as fuel, or for application as APU (auxiliary power unit) in automotive applications. 

The modular design of the HyPM fuel cells allows scaling for higher power requirements using a variety of configurations, such as series and parallel systems. Potential applications for the technology include vehicle propulsion, auxiliary power units (APU), stationary applications including backup and standby power units, combined heat and power units and portable power applications for the construction industry and the military. 

In addition to high-profile fuel cell applications such as automotive propulsion and distributed power generation, the use of fuel cells as auxiliary power units (APUs) for vehicles has received considerable attention (see Figure 1-9). APU applications may be an attractive market because it offers a true mass-market opportunity that does not require the challenging performance and low cost required for propulsion systems for vehicles. In this section, a discussion of the technical performance requirements for such fuel cell APUs, as well as the current status of the technology and the implications for fuel cell system configuration and cost is given. 

A compact design for a gasoline fuel processor for auxiliary power unit (APU) applications, including an autothermal reformer followed by WGS and selective oxidation stages, was reported by Severin et al. [83]. The overall fuel processor efficiency was about 77% with a start-up time of 30 min. 

Design, construct and evaluate a compact integrated auxiliary power unit (APU) of - 5 kW, together with fuel reforming facilities 2003... 

A further example would be the silent watch auxiliary power unit developed by Hydrogenics for the Canadian Coyote armoured vehicle. This proton exchange membrane (PEM) fuel cell APU also uses hydrogen stored as a metal hydride. Hydrogen is produced using an on-board electrolyser powered during operation of the diesel engine. 

Supercapacitors [75,76] and fuel cells [77,78] have also been proposed for road vehicles, but are not expected to be widely used in the present decade. As an auxiliary power unit (APU), a fuel cell could replace the alternator for the generation of electrical energy. The motivation for this change would be higher overall efficiency. 

Identified diesel-based 5-kWe fuel cell auxiliary power unit (APU) system with >50% electrical conversion efficiency... 

Designed and fabricated components for a new 22 W stack for portable power applications and a new 500 W stack for auxiliary power unit (APU) applications. 

By this standard bus bars are summarized in an airplane. Consumers of the cabin are, for example, less important than the cockpit devices. Of utmost importance is of coiu e the flight cmitrol. Even at a total failure all internal combustion engines, such as the main engines and the auxiliary power unit (APU), during flight at maximum cruise height the controllability of the aircraft and safe landing at an alternative airport must be ensured. 

Honeywell, Produktbeschreibung, APU 131-9[A] Auxiliary Power Unit, April 2013... 

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