Simulated diesel engine conditions

Preliminary tests conducted, using AARL catalysts, catalyst Marsh and co-workers [145] (see above) under simulated diesel engine conditions with oxygen content of 7.5%, showed significant activity for NOj, reduction. Favourable results showed a CO T50 of 333 K and an HC T50 of 443 K. An NO, conversion window was observed at temperatures between 493 and 623 K, with a T50 of 523 K and a maximum conversion of 66% at 563 K. 

However, under more realistic test conditions Hancock and Islam showed that in burner rig tests with contaminant flux rates greater than about 0-1 mgcm h" the corrosion rate of nickel- and cobalt-base superalloys was largely independent of alloy composition in the temperature range 7(X)-850 C. However, in burner rig tests at 6(X) C, simulating diesel engine combustion, Saunders et reported that Nimonic 80A (20% Cr) had superior resistance to Stellite 6 (Co-28%Cr) and EN 52 (Fe-8%Cr-3%Si). 

Figure 13. Particle number distributions for a diesel engine (2.5 L displacement, direct injection, 4-cylinder, 1500 rpm, 7.5 kW) mn with 300 ppm sulfur content diesel fuel. Distributions are measured using a dilution tunnel with conditions simulating those expected in the environment (final dilution ratio of approximately 100 1). From Collings and Graskow (2000). Used by permission of the Royal Society.

Fig. 17.6 Schematic of the 4.0 L heavy duty Diesel engine used for the simulation of the complete SCR system under unsteady flow condition...

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