AN EXPERIMENTAL STUDY OF A PASSIVE NOx ADSORBER (PNA) FOR THE REDUCTION OF COLD START DIESEL EMISSIONS

Berndt, Conor T.

doi:10.37099/mtu.dc.etdr/936

Cited by 3 publications

(3 citation statements)

References 9 publications

(72 reference statements)

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“…Previous work shows that the addition of passive NO x adsorber (PNA) in the AT system was useful in reducing NO x emissions during the cold start (Milovanovic et al, 2016;Berndt, 2019). However, as the PNA has a limit for the NO x adsorption, this might not be very helpful, especially during an LLC where the exhaust temperatures are too low for a prolonged duration.…”

Section: Introductionmentioning

confidence: 99%

Meeting future NOX emission regulations by adding an electrically heated mixer

et al. 2022

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New regulations by the California Air Resources Board (CARB) demand a stringent 0.02 g/hp-hr tailpipe NOx limit by the year 2027, requiring Selective Catalytic Reduction (SCR) catalysts to provide high NOx conversions even at low (below 200°C) exhaust temperatures. This work describes utilizing an Electrically Heated Mixer System (EHM system) upstream of a Light-Off Selective Catalytic Reduction (LO-SCR) catalyst followed by a conventional aftertreatment (AT) system containing DOC, DPF, and SCR, enabling high NOx conversions meeting CARB’s NOx emission target. The AT catalysts were hydrothermally aged to Full Useful Life. Conventional unheated Diesel Exhaust Fluid (DEF) was injected upstream of both the LO-SCR and primary downstream SCR. The EHM system allowed for DEF to be injected as low as 130°C upstream of the LO-SCR, whereas, in previous studies, unheated DEF was injected at 180°C or dosed at 130°C with heated DEF. The combination of unheated DEF, EHM system, LO-SCR, and downstream SCR enabled the needed increase in NOx efficiency in low exhaust temperatures, which was observed in drive cycles such as in cold-FTP, LLC, and World Harmonized Transient Cycle (WHTC). There were several-fold reductions in tailpipe NOx using this configuration compared to its baseline: 3.3-fold reduction in FTP, 22-fold in Low Load Cycle (LLC), 38-fold in Beverage Cycle, 8-fold in “Stay Hot” Cycle, and 10-fold in WHTC. Finally, it is shown that the EHM system can heat the exhaust gas, such as during a cold start, without needing additional heating hardware integrated into the system. These results were observed without performing changes in the engine base calibration.

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Section: Introductionmentioning

confidence: 99%

Meeting future NOX emission regulations by adding an electrically heated mixer

et al. 2022

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“…One of the key challenges for using the 'Low-NOx' concept is the excessive dilution requirement [20,21], which causes reduced exhaust gas temperatures, leading to a deteriorated ATS performance. Therefore, for HD hybrid powertrains, Advanced ATS configurations and effective exhaust thermal management are imperative for compliance with the tailpipe NOx emissions limits, particularly at low-load and cold ambient operations [22][23][24][25]. To that end, the use of an electric heater component (EHC) can accelerate the selective catalytic reduction (SCR) catalyst warm-up [26], making it a low-cost system compared with alternatives like burner [27,28] and dynamic skip fire (DSF) concepts [29].…”

Section: Introductionmentioning

confidence: 99%

E-Heater Performance for Aftertreatment Warm-Up in a 48V Mild-Hybrid Heavy-Duty Truck over Real Driving Cycles

Kumar,

Lago Sari,

Shah

et al. 2024

Energies

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High-efficiency and low-emissions heavy-duty (HD) internal combustion engines (ICEs) offer significant GHG reduction potential. Mild hybridization via regenerative braking and enabling the use of an electric heater component (EHC) for the aftertreatment system (ATS) warm-up extends these benefits, which can mitigate tailpipe GHG and NOx emissions simultaneously. Understanding such integrated hybrid powertrains is essential for the system optimization of real-world driving conditions. In the present work, the potential of a low engine-out NOx (1.5–2.5 g/kWh range) ‘Low-NOx’ HD diesel engine and EHCs were analyzed in a 48V P1 mild-hybrid system for a class 8 commercial vehicle concept and compared with those in an EPA-2010-certified HD diesel truck as a baseline under real-world driving cycles, including those from the US, Europe, India, China, as well as the world harmonized vehicle cycle (WHVC). For analysis, an integrated 1-D vehicle model was utilized that consisted of models of the ‘Low-NOx’ HD engine, the stock ATS, and a production EHC. For the real driving cycles, ‘GT-RealDrive’-based vehicle speed profiles were generated for busy trucking routes for different markets. For each cycle, the effects of the Low-NOx and EHC performances were quantified in terms of the ATS warm-up time, engine-out NOx emissions, and net fuel consumption. Depending on the driving route, the regenerative braking fully or partly neutralized the EHC power penalty without a significant impact on the ATS thermal performance. For a two-EHC system, the fueling penalty associated with every second reduction in the warm-up time FCEHC (g/s) was several-fold higher for the real driving routes compared with the WHVC. Overall, while a multi-EHC setup accelerated the ATS warm-up, a single EHC integrated at the SCR inlet showed minimized EHC heating power, leading to a minimized fueling penalty. Finally, for the India and China routes, being highly transient, the P1 hybridization proved inadequate for GHG reduction due to the limited energy recuperation. A stronger hybridization was desirable for such driving cycles.

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“…There have been several advances to reduce NO x emissions from heavy-duty engines (Milovanovic et al, 2016;Berndt, 2019;Zavala et al, 2020). The main area where the aftertreatment system struggles to reduce NO x is during low exhaust temperature conditions, when the Selective Catalytic Reduction (SCR) catalytic activity is limited (Scott Sluder et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Meeting future NOX emissions using an electric heater in an advanced aftertreatment system

Meruva

Matheaus²,

Sharp³

et al. 2022

Front. Mech. Eng.

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Engine and aftertreatment solutions are being identified to meet the upcoming ultra-low NOx regulations on heavy duty vehicles as published by the California Air Resources Board (CARB) and proposed by the United States Environmental Protection Agency (US EPA) for the year 2027 and beyond. These standards will require changes to current conventional aftertreatment systems for dealing with low exhaust temperature scenarios. One approach to meeting this challenge is to supply additional heat from the engine; however, this comes with a fuel penalty which is not attractive and encourages other options. Another method is to supply external generated heat directly to the aftertreatment system. The following work focuses on the later approach by maintaining the production engine calibration and coupling this with an Electric Heater (EH) upstream of a Light-Off Selective Catalytic Reduction (LO-SCR) followed by a primary aftertreatment system containing a downstream Selective Catalytic Reduction (SCR). External heat is supplied to the aftertreatment system using an EH to reduce the Tailpipe (TP) NOx emissions with minimal fuel penalty. Two configurations have been implemented, the first is a Close Coupled (CC) LO-SCR configuration and the second is an Underfloor (UF) LO-SCR configuration. The CC LO-SCR configuration shows the best outcome as it is closer to the engine, helping it achieve the required temperature with lower EH power while the UF LO-SCR configurations addresses the real-world packaging options for the LO-SCR. This work shows that a 7 kW EH upstream of a LO-SCR, in the absence of heated Diesel Exhaust Fluid (DEF), followed by a primary aftertreatment system met the 2027 NOx regulatory limit. It also shows that the sub-6-inch diameter EH with negligible pressure drop can be easily packaged into the future aftertreatment system.

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AN EXPERIMENTAL STUDY OF A PASSIVE NOx ADSORBER (PNA) FOR THE REDUCTION OF COLD START DIESEL EMISSIONS

Cited by 3 publications

References 9 publications

Meeting future NOX emission regulations by adding an electrically heated mixer

Meeting future NOX emission regulations by adding an electrically heated mixer

E-Heater Performance for Aftertreatment Warm-Up in a 48V Mild-Hybrid Heavy-Duty Truck over Real Driving Cycles

Meeting future NOX emissions using an electric heater in an advanced aftertreatment system

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