Meeting Future NOx Emissions Limits with Improved Total Fuel Efficiency

Harris, Tony; McCharthy, James; Sharp, Christopher; Zavala, Bryan; Matheaus, Andrew

doi:10.1007/978-3-658-38105-9_11

Cited by 4 publications

(1 citation statement)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…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

View full text Add to dashboard Cite

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.

show abstract

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

View full text Add to dashboard Cite

show abstract

Meeting Future NO <sub>X</sub> Emissions Over Various Cycles Using a Fuel Burner and Conventional Aftertreatment System

McCarthy¹,

Matheaus²,

Zavala³

et al. 2022

SAE Int. J. Adv. & Curr. Prac. in Mobility

View full text Add to dashboard Cite

<div class="section abstract"><div class="htmlview paragraph">The commercial vehicle industry continues to move in the direction of improving brake thermal efficiency while meeting more stringent diesel engine emission requirements. This study focused on demonstrating future emissions by using an exhaust burner upstream of a conventional aftertreatment system. This work highlights system results over the low load cycle (LLC) and many other pertinent cycles (Beverage Cycle, and Stay Hot Cycle, New York Bus Cycle). These efforts complement previous works showing system performance over the Heavy-Duty FTP and World Harmonized Transient Cycle (WHTC). The exhaust burner is used to raise and maintain the Selective Catalytic Reduction (SCR) catalyst at its optimal temperature over these cycles for efficient NO<sub>X</sub> reduction. This work showed that tailpipe NO<sub>X</sub> is significantly improved over these cycles with the exhaust burner. In certain cases, the improvements resulted in tailpipe NO<sub>X</sub> values well below the adopted 2027 LLC NO<sub>X</sub> standard of 0.05 g/hp-hr, providing significant margin. In fact, near zero NO<sub>X</sub> was measured on some of these cycles, which goes beyond future regulation requirements. However, burner operation on the tested cycles also resulted in a CO<sub>2</sub> increase, indicating that a different burner calibration strategy, or possibly an additional technology, will be needed to achieve lower CO<sub>2</sub> emissions.</div></div>

show abstract