Diesel cycle engines applications

Fuel cells are being proposed to replace Otto or diesel engines because they are reliable, simple, and quieter, less polluting, and economical. The internal combustion Otto or diesel cycle engine has been used in automobiles for about 100 years now. A reasonably simple and reliable mechanical device nowadays has a lifespan of up to 400,000 km in automobiles and over 1,000,000 km in larger applications such as buses and trucks. 

All three catalyst configurations have been tested in a scenario comprising of consecutive lean-rich cycles at different temperatures and space velocities in the range of practical interest for diesel engine applications. Comparative results for the three systems, in terms of NO conversion efficiency, are presented in Fig. 13.24. 

In summaiy, diesel fuel with veiy low to no sulfur content is now possible with chemical and technological advances. Along with catalytic converters, electronic fuel systems, and sensors, the diesel engine for the new millennium will he capable of complying with ever more stringent EPA exliaust emissions. The diesel engine will continue to sei"ve as the main global workliorse for all of the many thousands of different applications of its power cycle. 

Combined-cycle systems are used in both land and marine applications employing diesel engines or gas turbines (which usually provide the first power source) and by large process industries that produce significant heat-containing, by-product waste streams. 

However, there are several major drawbacks that hinder practical application of this NOx reduction method in automobile exhaust aftertreatment (i) The NO reduction activity is typically limited to a certain temperature window, for NM-based catalysts it is around the light-off—cf. Fig. 14 and Ansell et al. (1996), Jirat et al. (1999b), Burch et al. (2002) and Joubert et al. (2006). (ii) With low HC concentrations and the exhaust composition met in modern diesel engines, the achieved NOx conversions in real driving cycles are quite low (typically around 5-10%, cf., e.g., Kryl et al, 2005). (iii) The selectivity of NOx reduction is problematic, N20 may form up to 50% of the product (Burch et al., 2002 Joubert et al., 2006). Alternative (Cu-, Co-, Ag-, etc., based) catalysts may provide a wider temperature window or better selectivity for... 

Internal combustion engines, such as the diesel engine, are the primary source in some smaller units. They require clean-burning fuels with certain characteristics. Closed-cycle power systems with external firing, which are more common in chlor-alkali plant applications, can use almost any fuel. 

Main industrial applications are on two- and four-cycle diesel engines, gas engines, and dual-fuel engines. 

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