CARB Low NOX Stage 3 Program - Final Results and Summary

Sharp, Christopher; Neely, Gary D.; Zavala, Bryan; Rao, Sandesh

doi:10.4271/2021-01-0589

Cited by 31 publications

(28 citation statements)

References 12 publications

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“…Previous work (Sharp et al, 2021) utilized a heated doser in front of the LO-SCR. A heated doser allows DEF dosing down to 130 °C exhaust temperature instead of the normal dosing temperature of 180 °C for most advanced SCR systems.…”

Section: Aftertreatmentmentioning

confidence: 99%

“…There were two approaches to the LO-SCR aftertreatment configuration in this program that is relevant to packaging on a Class 8 Truck: 1) Close-Coupled (CC) LO-SCR and 2) Underfloor (UF) LO-SCR. The first approach was to represent a similar aftertreatment configuration as the Stage 3 Low NO x program (Sharp et al, 2021) and the second approach was to consider a real-world issue of packaging the LO-SCR on the chassis rail. As mentioned earlier, Figure 1B shows the baseline configuration of the LO-SCR.…”

Section: Aftertreatmentmentioning

confidence: 99%

“…Most of the ongoing research works to achieve 2027 NO x regulations are with the addition of Light-Off Selective Catalytic Reduction (LO-SCR) to the current production aftertreatment systems (Kasab et al, 2021b;Sharp et al, 2021;Zavala et al, 2022). The LO-SCR gains a benefit of reaching the light off temperature faster than the primary SCR by staying closer to the engine.…”

Section: Introductionmentioning

confidence: 99%

“…The EH heaters are analyzed on different aftertreatment configurations and compared with the baseline aftertreatment system to analyze the NO x -CO 2 trade off. calibration similar to the engine utilized in the CARB Stage 3 onroad baseline testing (Sharp et al, 2021). The engine retained the production air handling system, Exhaust Gas Recirculation (EGR) system, internal components, and fuel system.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Aftertreatmentmentioning

confidence: 99%

Section: Aftertreatmentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Meruva

Matheaus²,

Sharp³

et al. 2022

Front. Mech. Eng.

View full text Add to dashboard Cite

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“…This is due to the higher volatility, lower viscosity, longer ignition delay, and better fuel-air mixing achieved with gasoline-like fuels. The improved soot-NOx tradeoff could also help alleviate the tremendous operational and durability demands placed on modern lean aftertreatment systems for meeting upcoming emissions regulations (Lee et al, 2017;Lee et al, 2019;Sharp et al, 2021). Optimizing the combustion system for GCI (i.e., piston bowl shape, injector, and air system configurations) also has the potential to improve fuel economy compared to the most efficient internal combustion engines today (Kumar et al, 2019;Pei et al, 2019;Sellnau et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Non-Reacting Spray Characteristics of Gasoline and Diesel With a Heavy-Duty Single-Hole Injector

et al. 2022

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Gasoline compression ignition (GCI) is a promising combustion technology that could help alleviate the projected demand for diesel in commercial transport while providing a pathway to achieve upcoming CO2 and criteria pollutant regulations for heavy-duty engines. However, relatively high (i.e., diesel-like) injection pressures are needed to enable GCI across the entire load range while maintaining soot emissions benefits and managing heat release rates. There have only been a limited number of previous studies investigating the spray characteristics of light distillates with high-pressure direct-injection hardware under charge gas conditions relevant to heavy-duty applications. The current work aims to address this issue while providing experimental data needed for calibrating spray models used in simulation-led design activities. The non-reacting spray characteristics of two gasoline-like fuels relevant to GCI were studied and compared to ultra-low-sulfur diesel (ULSD). These fuels shared similar physical properties and were thus differentiated based on their research octane number (RON). Although RON60 and RON92 had different reactivities, it was hypothesized that they would exhibit similar non-reacting spray characteristics due to their physical similarities. Experiments were conducted in an optically accessible, constant volume combustion chamber using a single-hole injector representing high-pressure, common-rail fuel systems. Shadowgraph and Mie-scattering techniques were employed to measure the spray dispersion angles and penetration lengths under both non-vaporizing and vaporizing conditions. Gasoline-like fuels exhibited similar or larger non-vaporizing dispersion angle compared to ULSD. All fuels followed a typical correlation based on air-to-fuel density ratio indicating that liquid density is the main governing fuel parameter. Injection pressure had a negligible effect on the dispersion angle. Gasoline-like fuels had slower non-vaporizing penetration rates compared to ULSD, primarily due to their larger dispersion angles. As evidenced by the collapse of data onto a non-dimensional penetration correlation over a wide range of test conditions, all fuels conformed to the expected physical theory governing non-vaporizing sprays. There was no significant trend in the vaporizing dispersion angle with respect to fuel type which remained relatively constant across the entire charge gas temperature range of 800–1200 K. There was also no discernable difference in vapor penetration among the fuels or across charge temperature. The liquid length of gasoline-like fuels was much shorter than ULSD and exhibited no dependence on charge temperature at a given charge gas pressure. This behavior was attributed to gasoline being limited by interphase transport as opposed to mixing or air entrainment rates during its evaporation process. RON92 had a larger non-vaporizing dispersion angle but similar penetration compared to RON60. Although this seems to violate the original similarity hypothesis for these fuels, the analysis was made difficult due to the use of different injector builds for the experiments. However, RON92 did show a slightly larger vapor dispersion angle than RON60 and ULSD. This observation was attributed to nuanced volatility differences between the gasoline-like fuels and indicates that vapor dispersion angle likely relies on a more complex correlation beyond that of only air-to-fuel density ratio. Finally, RON92 showed the same quantitative liquid length and insensitivity to charge gas temperature as RON60.

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