An Urea Lean NOx Catalyst System for Light Duty Diesel Vehicles

Lüders, Hartmut; Backes, R.; Hüthwohl, G.; Ketcher, D. A.; Horrocks, R. W.; Hurley, R. G.; Hammerle, R. H.

doi:10.4271/952493

Cited by 25 publications

(12 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The lower NO x reduction efficiency at the urban phase and cold start is in line with the dependency of the SCR efficiency with the temperature (e.g. Jung et al, 2017 ; Lüders et al, 1995 ). The technical approach of the retrofit having SCR function added downstream of the DPF and avoid any changes to the original engine and aftertreatment configuration puts some natural constraints to the cold-start performance.…”

Section: Discussionsupporting

confidence: 60%

Evaluation of NOx emissions of a retrofitted Euro 5 passenger car for the Horizon prize “Engine retrofit”

Giechaskiel

Suarez-Bertoa

Lähde

et al. 2018

Environmental Research

View full text Add to dashboard Cite

The Horizon 2020 prize for the “Engine Retrofit for Clean Air” aims at reducing the pollution in cities by spurring the development of retrofit technology for diesel engines. A Euro 5 passenger car was retrofitted with an under-floor SCR (Selective Catalytic Reduction) for NOx catalyst in combination with a solid ammonia based dosing system as the NOx reductant. The vehicle was tested both on the road and on the chassis dynamometer under various test cycles and ambient temperatures. The NOx emissions were reduced by 350–1100 mg/km (60–85%) in the laboratory depending on the test cycle and engine conditions (cold or hot start), except at type approval conditions. The reduction for cold start urban cycles was < 75 mg/km (< 15%). The on road and laboratory tests were inline. In some high speed conditions significant increase of ammonia (NH3) and nitrous oxide (N2O) were measured. No effect was seen on other pollutants (hydrocarbons, carbon monoxide and particles). The results of the present study show that retrofitting high emitting vehicles can significantly reduce vehicle NOx emissions and ultimately pollution in cities.

show abstract

Section: Discussionsupporting

confidence: 60%

Evaluation of NOx emissions of a retrofitted Euro 5 passenger car for the Horizon prize “Engine retrofit”

Giechaskiel

Suarez-Bertoa

Lähde

et al. 2018

Environmental Research

View full text Add to dashboard Cite

show abstract

“…The reason is that the NO 2 is formed at the DOC at high exhaust gas temperatures, where the retrofit works efficiently, combined with the effect of the fast SCR reaction at low temperature. The lower NO x reduction efficiency at the urban phase and cold start is in line with the dependency of the SCR efficiency with the temperature (e.g., [26][27][28]). The technical approach of the retrofit having SCR function added downstream of the DPF and avoiding any changes to the original engine and aftertreatment configuration puts some natural constraints to the cold-start performance.…”

Section: No X Reduction Of the Retrofitsupporting

confidence: 65%

Emissions of a Euro 6b Diesel Passenger Car Retrofitted with a Solid Ammonia Reduction System

et al. 2019

View full text Add to dashboard Cite

Nitrogen oxides (NOx) emissions from diesel vehicles are a serious environmental concern. Prior to the introduction of on-road tests at type approval, vehicle on-road NOx emissions were found many times higher than the applicable limits. Retrofitting an existing vehicle is a short/mid-term solution. We evaluated a NOx reduction retrofit system installed on a Euro 6b diesel passenger car both in the laboratory and on the road. The retrofit consisted of an under-floor SCR (selective catalytic reduction) for NOx catalyst in combination with a solid ammonia-based dosing system as the NOx reductant. The retrofit reduced NOx emissions from 25% (50 mg/km) to 82% (725 mg/km) both in the laboratory and on the road. The minimum reduction was achieved at cold start cycles and the maximum at hot start cycles. The retrofit had small effect on CO2 (fuel consumption). No ammonia emissions were detected and the N2O increase was negligible at cold start cycles, but up to 18 mg/km at hot start cycles. The results showed that the retrofit technology could be beneficial even for high emitting Euro 6b diesel vehicles.

show abstract

“…During extended idle periods, the load on the engine reduces, causing a reduction in the exhaust mass flow along with a decrease in exhaust temperature. The average exhaust temperature during "extended" idle periods is ∼165 °C, well below the optimal temperature (200-250 °C) required for the SCR system to functionally dose Diesel Exhaust Fluid (DEF), which is required to convert NO/NO 2 , and in turn reduce the overall NO X emissions [31,32,33,34,35,36,37,38,39,40].…”

Section: Eu Stage IV Machinesmentioning

confidence: 99%