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Through microscopic visualization experiments, a process generally known as depth filtration was shown to be caused by surface pores. Moreover, the existence of a soot cake layer was an important advantage for filtration performance because it could trap most of the particulates. We proposed an ideal diesel particulate filter (DPF), in which a silicon carbide (SiC) nanoparticle membrane (made from a mixture of 80 nm and 500 nm powders) instead of a soot cake was sintered on the DPF wall surface; this improved the filtration performance at the beginning of the trapping process and reduced energy consumption during the regeneration process. The proposed filter was called a diesel particulate membrane filter (DPMF). A diesel fuel lamp was used in the trapping process to verify the trapping and oxidation mechanisms of ultrafine particulate matter. Thus, the filtration performance of the membrane filters was shown to be better than that of conventional DPFs.

The development of exhaust nozzles and their application in operational military aircraft are discussed. Prime consideration is given to installation factors such as engine bay and nozzle cooling, inlet-engine flow matching, and aerodynamic effects on external afterbody drag. Examples of various operational exhaust systems are given which show how the aircraft-exhaust nozzle characteristics are integrated to achieve maximum system compatibility and performance. Results from one flight test program are presented which show how an aircraft-exhaust nozzle system was integrated to achieve maximum installed performance.

Urea-SCR systems have become one effective method for meeting the ever tightening NOx emission control regulations for diesel engines. Higher activity of SCR catalysts in the low temperature region is crucial for meeting emission regulations and improving fuel economy. Some of the new catalytic components in the literature have shown good low temperature SCR activity, but they have not been fully confirmed to be durable enough for mobile applications. Fe-zeolite has been widely used in mobile applications due to its wide operating temperature window, but after exposure to large amounts of HCs at low temperatures, it is easily deactivated. We developed new SCR catalysts with improved low temperature activity and improved durability against HC fouling and thermal sintering by combining OSC (oxygen storage component) with Fe-zeolite.

Many diesel engines have to work at load profiles which, due to the low exhaust gas temperatures, necessitate active regeneration procedures to ensure continued engine operation and the reliability of the particulate filter. An active regeneration may be initiated via inner engine measures such as late injection. However, due to high maintenance interval and run time requirements for non-road applications the combustion of soot accumulated in the diesel particulate filter (DPF) often is realized via downstream processes. Known methods for this purpose are burner systems, systems based on downstream hydrocarbon injection (HCI) and subsequent hydrocarbon (HC)-conversion due to a catalyst or a combination of both. This paper describes an autarkic system using two-stage electro-thermal-supported hydrocarbon conversion. This system is capable to regenerate a DPF within the entire engine operating range and it is less complex than flame burner systems.

Improved design features have made the pivoted-target thrust reverser concept most attractive for modern small turbofans with coaxial flow exhaust systems. These aerodynamic, mechanical and structural design improvements provide 40% or more reverse thrust effectiveness in a simple, light weight, low cost unit that has clean aerodynamic lines and minimum effect on engine performance. The pivoted-target thrust reverser system, under development at Grumman for the AiResearch TFE-731-2 and -3 engines, is described. Applications include the IAI Westwind 1124, the Gates Learjet 35/36 and the Dassault Falcon 10 aircraft.

Exhaust emissions are well known to have adverse impacts on human health. Studies have demonstrated that there is an association between ambient particulate matter (PM) levels and various harmful cardiopulmonary conditions. Soot exhaust from diesel engines can be a significant contributor to airborne pollutants. A key component in PM level control for a diesel engine is a diesel particulate filter (DPF). This device traps soot while allowing other exhaust gases to pass unhindered. However, the performance of diesel particulate filters can change with increasing soot loadings and thus may require regeneration or replacement. Improved understanding of diesel particulate filters is dependent upon the knowledge of the actual soot loading and the soot distribution within the DPF. Neutron radiography (NR) has been identified as an effective means of non-destructively identifying hydrogen or carbon adsorbed in PM.

An outline history of the development of the turbo supercharger is presented, showing the progress of the supercharger and the related airplane parts. A brief history is given of the fuel systems, cooling systems, exhaust manifolds and nozzle boxes, turbine buckets, propellers, ignition systems, carbureters, intercoolers and bearings and lubrication, and a description of the developments that have recently taken place in these fields. A study is made of the power required by the compressor and power delivered by the turbine on the basis of certain assumptions that may be at variance with the facts. Nevertheless, the study shows trends and the general order of efficiencies. From this paper, the conclusion is reached that the turbo supercharger is a serviceable piece of equipment for maintaining sea-level pressure at the carbureters to altitudes.

Currently automotive engines are reciprocating or Wankel rotary engine types. Reciprocating engines are bulky, heavy and complex, mainly due to the intake and exhaust valves and their associated cam-train. Wankel engines have a low rotor rev limit, and have inefficient sealing of the apex seals leading to poor economy and undesirable emission gases. The Rotary Engine Development Agency (REDA) has designed a new three-chamber rotary internal combustion engine concept using an adaptation of the patented Szorenyi Curve. The new design is an evolution of the design which was the subject of SAE Technical Paper 2017-01-2413 and SAE publication ‘So You Want to Design Engines: UAV Propulsion Systems’. This paper describes the features of the new three-chamber engine concept and includes an analysis of the major shortcomings of the Wankel engine.

This paper describes two unconventional types of internal combustion reciprocating engines designed to drive rectified alternators to provide electrical power for space missions. The engines use Aerozine 50 as the fuel and nitrogen tetroxide as the oxidizer. These two propellants are commonly used in liquid rockets and are characterized by the combination of high energy release and immediate ignition upon contact. The first engine is designed to provide 6 hp using a plunger type propellant injection system and in-head exhaust valve. The second provides 4.5 hp using a unique pressure fed, cam-operated, poppet injector and cylinder exhaust ports. One of the critical problems in the design of these engines concerns the very short time interval during which the propellants must be injected and burned.

The particular design of the SNECMA thrust reverser on Concorde results specifically from the general nacelle arrangement, and also from the exhaust system requirements. In this context, the author justifies the present arrangement of the SNECMA thrust reverser system. He describes in detail the technological features and the tests completed, which allowed the thrust reverser system to meet performance, safety, airworthiness, and operational requirements for the flight development phase on the Concorde prototype. In this respect, further consideration is given to the reliability and maintenance aspects, as an important feature of the design.

This SAE Aerospace Information Report (AIR) reviews the precautions that must be taken and the corrections which must be evaluated and applied if the experimental error in measuring the temperature of a hot gas stream with a thermocouple is to be kept to a practicable minimum. Discussions will focus on Type K thermocouples, as defined in National Institute of Standards and Technology (NIST) Monograph 175 as Type K, nickel-chromium (Kp) alloy versus nickel-aluminium (Kn) alloy (or nickel-silicon alloy) thermocouples. However, the majority of the content is relevant to any thermocouple type used in gas turbine applications.

Transient and steady-state kinetic data are herein presented to analyze the inhibiting effect of ammonia on the NH₃-SCR of NO at low temperatures over a Fe-zeolite commercial catalyst for vehicles. It is shown that in SCR converter models a rate expression accounting for NH₃ inhibition of the Standard SCR reaction is needed in order to predict the specific dynamics observed both in lab-scale and in engine test bench runs upon switching on and off the ammonia feed. Two redox, dual site kinetic models are developed which ascribe such inhibition to the spill-over of ammonia from its adsorption sites, associated with the zeolite, to the redox sites, associated with the Fe promoter. Better agreement both with lab-scale intrinsic kinetic runs and with engine test-bench data, particularly during transients associated with dosing of ammonia to the SCR catalyst, is obtained assuming slow migration of NH₃ between the two sites.

The MIT-based Mars Gravity Biosatellite payload engineering team has been engaged in designing and prototyping sensor and control systems for deployment within the rodent housing zone of the satellite, including novel video processing and atmospheric management tools. The video module will be a fully autonomous real-time analysis system that takes raw video footage of the specimen mice as input and distills those parameters which are of primary physiological importance from a scientific research perspective. Such signals include activity level, average velocity and rearing behavior, all of which will serve as indicators of animal health and vestibular function within the artificial gravity environment. Unlike raw video, these parameters require minimal storage space and can be readily transmitted to earth over a radio link of very low bandwidth.

Recent improvement in exhaust after-treatment technologies allows particle removal up to 95% with traps and NOx removal up to 40% with reduction catalyst from diesel exhausts. The efficiency of the technology is mainly based on the rate of regulated pollutant emission reduction but very few information is available in term of health hazard potential which may be related to interactions with several of the hundreds of chemical species present under different phases (liquid, gas, solid). It is therefore necessary to develop useful tools to evaluate the global toxicity of Diesel exhaust. A model of bi-compartimental gas/liquid organotypic culture of lung tissue has been specifically developed and used for continuous in vitro exposure to the exhaust gas of a direct injection 1.9 l turbo-charged engine. Regulated emissions (CO, HC, NOx and particles) were measured in raw exhaust.

Through research and test work, the aircraft industry has gained a better knowledge of the design parameters which influence the noise produced by light propeller driven aircraft. The parameters found to have a major affect on the noise include: propeller tip speed, propeller blade tip thickness, and engine exhaust system characteristics. To date, many special design considerations such as geared or shrouded propellers have not proven effective in reducing noise levels. When developing an aircraft for reduced noise, its cost, performance, and utility must be considered.

An empirical relationship has been developed which permits the sizing of catalytic converters for control of vehicle exhaust emissions when the converter operates under mass transfer limited conditions. The relationship is based upon the inertia weight only, and may be utilized-within certain limitations- to determine the size of catalyst required for a given vehicle when another vehicle, which is equipped with a catalyst of proven durability, is used as a reference.

The ideal internal-combustion crankshaft engine would burn all the fuel near top center without detonation, then expand the whole charge until exhaust Both events are impossible with current piston engines. The Hydrocycle Rocket Piston Engine concept employs a free piston in the head of a two-stroke-cycle engine. Combustion between the crank piston and the free piston allows direct conversion of combustion fluid expansion to hydrostatic fluid flow and accumulator gas compression with perfect timing and minimum thermal and mechanical losses. An infinitely variable, radial hydrostatic motor gives the driver smooth, gas-cushioned acceleration and stepless performance. Maximum economy is attained since the driver is forced to run the engine at optimum minimum speed to match road load oadin all traffic conditions.

Regulated emissions (THC, CO, NOx, and PM) and particulate SOF and sulfate fractions were determined for a 1995 Detroit Diesel Series 50 urban bus engine at varying fuel sulfur levels, with and without catalytic converters. When tested on EPA certification fuel without an oxidation catalyst this engine does not appear to meet the 1994 emissions standards for heavy duty trucks, when operating at high altitude. An ultra-low (5 ppm) sulfur diesel base stock with 23% aromatics and 42.4 cetane number was used to examine the effect of fuel sulfur. Sulfur was adjusted above the 5 ppm level to 50, 100, 200, 315 and 500 ppm using tert-butyl disulfide. Current EPA regulations limit the sulfur content to 500 ppm for on highway fuel. A low Pt diesel oxidation catalyst (DOC) was tested with all fuels and a high Pt diesel oxidation catalyst was tested with the 5 and 50 ppm sulfur fuels.

Document provides information on how military/commercial/gas turbine engine test cell/system users may benefit from this unique Coanda/Refraction concept.