Automotive Engineering-Aftertreatment Technologies

Explain why aftertreatment became mandatory, and how emission norms outpace internal combustion control; introduce aftertreatment systems such as lean NOx traps and DPF in series configurations.

Examine the three-way catalytic converter that converts NOx, hydrocarbons, and carbon monoxide into harmless products using rhodium, platinum, and palladium on a ceramic honeycomb, with emphasis on light-off temperature.

Compare three catalytic converter substrates: ceramic magnesium aluminum silicate, ceramic mcnicholl silicate, and metallic honeycomb, all impregnated with platinum, rhodium, and palladium to catalyze exhaust gases.

Explore how diesel oxidation catalysts convert monoxide and hydrocarbons to carbon dioxide and water, and how diesel particulate filters trap particulates with 90% efficiency, including active and passive regeneration.

Explore exhaust gas recirculation (EGR), which recycles exhaust to the intake to dilute air, lower combustion temperature, and reduce NOx, while noting rough idling, particulate matter, and higher costs.

Learn how selective catalytic reduction uses diesel exhaust fluid (AdBlue) to reduce NOx by converting it into nitrogen and water vapor, guided by sensors and feedback to the main computer.

Explore lean NOx trap technology that stores NOx in the catalytic converter during lean operation. Learn how alternating lean and rich cycles regenerate the trap and influence fuel consumption.

Explore how diesel particulate filters trap soot and organic compounds, aided by catalyst-impregnated ceramic substrates and heated exhaust gas, while detailing impaction, interception, and diffusion mechanisms.

Explore diesel particulate filter types, including wire mesh and ceramic honeycomb traps. Observe candle-type filters and note active regeneration through fuel injection.

Explore how air-fuel ratio is controlled via lambda concepts, stoichiometric 14.7:1, and how heated lambda sensors measure exhaust oxygen to enable fast, closed-loop fuel correction.