Diesel models

In the following sections, the application of modelling to diesel after-treatment will be addressed. However, given that these diesel models are developed using a similar approach and methodology to the TWC models, the emphasis in these sections will be on application of the models to system design and understanding. 

The leading LD diesel non-methane HC and NOx regulations are graphically shown in Fig. 1.2. Only the US (Federal and CaUfomia LEVIII) has the test-cycle and limit value combination to force NOx aftertreatment. All require a DPF (regulations not shown). By 2013, perhaps a dozen diesel models will be on the US market. However, the majority of Euro 6 applications will have NOx aftertreatment to minimize NO2 emissions and fuel consumption. 

An important appHcation of MMCs in the automotive area is in diesel piston crowns (53). This appHcation involves incorporation of short fibers of alumina or alumina—siHca in the crown of the piston. The conventional diesel engine piston has an Al—Si casting alloy with a crown made of a nickel cast iron. The replacement of the nickel cast iron by aluminum matrix composite results in a lighter, more abrasion resistant, and cheaper product. Another appHcation in the automotive sector involves the use of carbon fiber and alumina particles in an aluminum matrix for use as cylinder liners in the Prelude model of Honda Motor Co. 

Effective with the 1982 model year, particulate matter from diesel vehicles was regulated by the U.S. Environmental Protection Agency for the first time, at a level of 0.37 gm km . Diesel vehicles were allowed to meet an NO level of 0.93 gm km under an Environmental Protection Agency waiver. These standards were met by a combination of control systems, primarily exhaust gas recirculation and improvements in the combustion process. For the 1985 model year, the standards decreased to 0.12 gm of particulate matter per kilometer and 0.62 gm of NO per kilometer. This required the use of much more extensive control systems (1). The Clean Air Act Amendments of 1990 (2) have kept the emission standards at the 1985 model level with one exception diesel-fueled heavy trucks shall be required to meet an NO standard of 4.0 gm per brake horsepower hour. 

VFO works well in gas turbines. In a nine-month test program, the combustion properties of VFO were studied in a combustion test module. A gas turbine was also operated on VFO. The tests were conducted to study the combustion characteristics of VFO, the erosive and corrosive effects of VFO, and the operation of a gas turbine on VFO. The combustion tests were conducted on a combustion test module built from a GE Frame 5 combustion can and liner. The gas turbine tests were conducted on a Ford model 707 industrial gas turbine. Both the combustion module and gas turbine were used in the erosion and corrosion evaluation. The combustion tests showed the VFO to match natural gas in flame patterns, temperature profile, and flame color. The operation of the gas turbine revealed that the gas turbine not only operated well on VFO, but its performance was improved. The turbine inlet temperature was lower at a given output with VFO than with either natural gas or diesel fuel. This phenomenon is due to the increase in exhaust mass flow provided by the addition of steam in the diesel for the vaporization process. Following the tests, a thorough inspection was made of materials in the combustion module and on the gas turbine, which came into contact with the vaporized fuel or with the combustion gas. The inspection revealed no harmful effects on any of the components due to the use of VFO. 

Answer The Markov model was prepared for one diesel having two states working and failed. For two diesels, the probability of both failing at the same time is X = Vi X X, t, where t is... 

PC-based models are presented for evaluating diesel unavailability. Parameters for the models are discussed in the report, but individual DG unavailability events are not listed. Generic TIs for a range of parameters and population of plants are displayed. 

The component failure rate data used as input to the fault tree model came from four basic sources plant records from Peach Bottom (a plant of similar design to Limerick), actual nuclear plant operating experience data as reported in LERs (to produce demand failure rates evaluated for pumps, diesels, and valves), General Electric BWR operating experience data on a wide variety of components (e.g., safety relief SRV valves, level sensors containment pressure sensors), and WASH-1400 assessed median values. 

The diesel engine is one of the most widely used global powcrplants and can be found in almost every conceivable application. From small single-cylinder models to V20 designs, their horsepower can range from as low as 3.73 kW (5 hp) to as high as 46,625 kW... 

Tn addition, a wide variety of military equipment, including tanks, armored personnel carriers, HUMVEEs and ships, is powered by diesel engines. The governed speed of diesel engines can range from as low as 85 rpm in large-displacement, slow-speed models, to as high as 5,500—6,000 rpm in smaller automotive type models. 

Desulfurization of FCC feedstocks reduces the sulfur content of FCC products and SOX emissions. In the United States, road diesel sulfur can be 500 ppm (0.05 wt%). In some European countries, for example in Sweden, the sulfur of road diesel is 50 ppm or less. In California, the gasoline sulfur is required to be less than 40 ppm. The EPA s complex model uses sulfur as a controlling parameter to reduce toxic emissions. With hydroprocessed FCC feeds, about 5% of feed sulfur is in the FCC gasoline. For non-hydroprocessed feeds, the FCC gasoline sulfur is typically 10% of the feed sulfur. 

Rayri, F., et al., CFD modeling of the in-cylinder flow in direct-injection diesel engines. Comput. Fluids, 2004. 33(8) 995-1021. 

Conceptual model of conventional Cl combustion characterized by a sequence of processes occurring in a fully developed reacting jet. (From Dec, A Conceptual Model of DI Diesel Combustion Based on Laser Sheet Imaging, SAE, 970873,1997. With permission.)... 

Studies on the particulate distributions from compressed natural gas (CNG) or diesel-fuelled engines with diesel oxidation catalyst (DOC) or partial diesel particle filter (pDPF) have also been performed. The results obtained are used as data for the model, to study the particle penetration into the human respiratory tracts. As a result, the number distribution of particles in different parts of lungs can be modeled [99-101]. Understanding the particle formation and their effects and finding the methods to ehminate the formed particulates from exhaust gas contribute to a cleaner urban environment and thus to a better quality of life. 

The reactor system works nicely and two model systems were studied in detail catalytic hydrogenation of citral to citronellal and citronellol on Ni (application in perfumery industty) and ring opening of decalin on supported Ir and Pt catalysts (application in oil refining to get better diesel oil). Both systems represent very complex parallel-consecutive reaction schemes. Various temperatures, catalyst particle sizes and flow rates were thoroughly screened. 

Analysis and modelling of the dynamic behaviour of the catalyst is useful to closely describe the performance during start up, shut down and load variation of stationary applications, and of critical relevance for SCR-NH3 of mobile diesel engine emissions. Use of dynamic models for exhaust transients has not been extensively reported in the literature for the design of improved catalysts, although it is a very valuable method. On the contrary, as will be discussed later, use of this tool to derive mechanistic implications is much less convincing. 

ExxonMobil extended the Hydrofining technology to produce a 200 ppm diesel, with the Diesel Oil Deep Desulfurization technology, DODD. The reactor is packed with multiple beds of different catalysts. A preceding history of commercial experience provided data to build a model for deep HDS and pave the way to a new technology, MAK Fining. 

Desulfurization of two LGO streams was studied using R. erythropolis rKA2-5-l [71] to determine the rate of desulfurization and develop a predictive model for desulfurization of diesel oil. The sulfur removal from various substituted DBTs was modeled using a competitive inhibition and lumping model and the desulfurization of the LGO streams was successfully assessed. The model consisted of a four component system based on... 

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