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Effective 1st April 2023, India's automotive emissions regulation has shifted from BS-VI Stage-1 to BS-VI Stage-2 standard the after-treatment systems need to demonstrate robust performance not just on the cycle, but also to demonstrate emissions for on-road Real Driving Emission (RDE) conditions. A stringent On-Board Diagnostics (OBD) strategy to monitor the real-time emission levels along with compliance Road Driving Emissions (RDEs) are focus areas for BS VI Stage-2 emission legislation. The maximum speed on MIDC is 90km/h in BS-VI Stage-1, Diesel Oxidation Catalyst (DOC)+Selective Catalyst Reduction Filter (SCRF®) was able to meet legislation at the lab, and now with the RDE cycle max speed of the vehicles under the M1 category <3.5 T will have the max permitted legal limit shall surpass 100 km/h for not around 3% of the span in the third phase of driving cycle for which max speed is up to 120 km/h.

This paper describes the after-treatment technology that could be used to meet a future BS-VII standard, considering close-coupled SCR (cc-SCR) to help start NOx conversion earlier. Both active (Cu/Fe-SCR based) and passive (V-SCR based) systems have the potential to meet emission limits. V-SCR may be considered in the rear position because V-SCR shows a fast response with very low N2O formation. Next-gen V-SCR technology shows significantly improved performance and durability closer to Cu-SCR. The steady-state NOx conversions over Next-Gen V-SCR were better than BS-VI V-SCR in both fresh and aged-580°C/100h conditions. High durability was also observed after engine aging of 1000h (WHTC + high load). Another big challenge in BS VII could be the PN10 requirement. With enhanced filtration coating (EFC) technology, PN emissions drop drastically in comparison to Euro VI reference without EFC to meet a future BS VII.

Until a proper fueling infrastructure is established, vehicles powered by natural gas must have bi-fuel capability in order to avoid a limited vehicle range. Although bi-fuel conversions of existing gasoline engines have existed for a number of years, these engines do not fully exploit the combustion and knock properties of both fuels. Much of the power loss resulting from operation of an existing gasoline engine on compressed natural gas (CNG) can be recovered by increasing the compression ratio, thereby exploiting the high knock resistance of natural gas. However, gasoline operation at elevated compression ratios results in severe engine knock. The use of variable intake valve timing in conjunction with ignition timing modulation and electronically controlled exhaust gas recirculation (EGR) was investigated as a means of controlling knock when operating a bi-fuel engine on gasoline at elevated compression ratios.

The New York State Department of Environmental Conservation (DEC) and Environment Canada have jointly participated along with partners the New York City Metropolitan Transit Agency (MTA); Johnson Matthey, Environmental Catalysts & Technologies; Equilon Enterprises, LLC and Corning, Inc. in a project to evaluate the effect of various combinations of fuels and aftertreatment configurations on diesel emissions. Emissions measurements were performed during engine dynamometer testing of an International DT 466E heavy-duty diesel engine. Fuels tested in the study were Diesel Fuel 1 and 2, low sulfur diesel (150 ppm), two ultralow sulfur fuels (<30 ppm), Fischer-Tropsch, Biodiesel, PuriNOx™ and two Ethanol-Diesel blends. Configurations tested were: engine out, and diesel oxidation catalyst, continuously regenerating diesel filter, and exhaust gas recirculation aftertreatment. In general, the use of more aggressive aftertreatment (ie.

Future emissions regulations proposed for the Asian automotive industry (BS VI regulations for India and NS VI regulations for China) are strict and similar to EU VI regulations. As a result, they will require both advanced NOx control as well as advanced Particulate Matter (PM) control. This will drive implementation of full Catalyzed Diesel Particulate Filter (cDPF) and simultaneous NOx control using Selective Catalytic Reduction (SCR) technologies. In this work, we present the performance of various Diesel Oxidation Catalyst (DOC), cDPF, SCR and Ammonia slip catalyst (ASC) systems utilizing the World Harmonized Transient Cycle (WHTC). Aftertreatment Systems (ATS) required for both active and passive filter regeneration applications will be discussed. The sensitivity of key design parameters like catalyst technology, PGM loading, catalyst sizing to meet the regulation limits has been investigated.

For diesel emission control technologies, reduction efficiencies of Particulate Matter (PM) control systems have been traditionally reported based on mass-based criteria. However, particle number-based criteria are now receiving increased attention. In this paper, results of real-time particle size distribution and number based evaluation of the effectiveness of multiple PM control technologies are reported on an HDD engine. An Engine Exhaust Particle Sizer (EEPS) was used for comparative analysis. The technologies that were evaluated included diesel oxidation catalysts (DOC), a DOC with an uncatalyzed wall-flow filter as a continuously regenerating diesel particulate filter (CR-DPF) system, a DOC with a catalytically coated wall-flow filter as a catalyzed CR-DPF (CCR-DPF), and a DOC with a partial filter as a continuously regenerating partial filter (CR-PF).

In 2007, the Environmental Protection Agency will begin measuring not only exhaust emissions from diesel engines, but also emissions from the crankcase if it is not vented into the engine intake. The 2007 government standards for emissions of carbon monoxide (CO), hydrocarbons (HC), oxides of nitrogen (NOx) and particulate matter (PM) will also become more restrictive. There is the additional concern that crankcase emissions from present day trucks and buses may impact the quality of air inside the vehicle. This paper presents data to characterize crankcase emissions and examines a crankcase emissions abatement system (CEAS), the New Condensator®, manufactured by World NCI. Rather than allowing crankcase emissions to leave via a vent tube, a CEAS re-circulates the emissions to the intake of the engine.

A recently completed program was developed to evaluate ultra-low sulfur diesel fuels and passive diesel particle filters (DPF) in several different truck and bus fleets operating in Southern California. The primary test fuels, ECD and ECD-1, are produced by ARCO, a BP company, and have less than 15 ppm sulfur content. A test fleet comprised of heavy-duty trucks and buses were retrofitted with one of two types of catalyzed diesel particle filters, and operated for one year. As part of this program, a chemical characterization study was performed in the spring of 2001 to compare the exhaust emissions using the test fuels with and without aftertreatment. A detailed speciation of volatile organic hydrocarbons (VOC), polycyclic aromatic hydrocarbons (PAH), nitro-PAH, carbonyls, polychlorodibenzo-p-dioxins (PCDD) and polychlorodibenzo-p-furans (PCDF), inorganic ions, elements, PM10, and PM2.5 in diesel exhaust was performed for a select set of vehicles.

The retrofitting of diesel engines with oxidation catalyst and particulate filter technology for the reduction of particulate matter (PM), hydrocarbons (HC) and carbon monoxide (CO) emissions has become an established practice. The design and performance of such systems have been commercially proven to the point that the application of these technologies is a cost effective means for states to effectively meet pollution reduction goals. One of the reasons that these technologies are so widely applied is because they can be sized and fitted based on easily measurable vehicle parameters and published engine emission information. These devices generally work passively with basic temperature and back pressure monitoring devices being used to alert the operator to upset conditions. The application of an effective NOx reduction technology in similar retrofit installation, is more complicated. There are no passive NOx reduction technologies that can be retrofit onto HDD vehicles.

The Tapered Element Oscillating Microbalance (TEOM) measures captured particle mass continuously on a small filter held on an oscillating element. In addition to traditional filter-based particulate matter (PM) measurement, a TEOM was used to characterize PM from the dilute exhaust of trucks examined in two phases (Phase 1.5 and Phase 2) of the Coordinating Research Council (CRC) Heavy-Duty Vehicle Emissions Inventory Project E-55/E-59. Test schedules employed were the Heavy Heavy-Duty Diesel Truck (HHDDT) test schedule that consists of four modes (Idle, Creep, Transient and Cruise), the HHDDT Short (HHDDT_S) which represents high-speed freeway operation, and the Heavy-Duty Urban Dynamometer Driving Schedule (UDDS). TEOM results were on average 6% lower than those from traditional particulate filter weighing. Data (in units of g/cycle) were examined by plotting cycle-averaged TEOM mass against filter mass. Regression (R2) values for these plots were from 0.88 to 0.99.

The new General Motors 2-mode hybrid transmission for front-wheel-drive vehicles has been incorporated into a 2009 Saturn Vue by the West Virginia University EcoCAR team. The 2-mode hybrid transmission can operate in either one of two electrically variable transmission modes or four fixed gear modes although only the electrically variable modes were explored in this paper. Other major power train components include a GM 1.3L SDE turbo diesel engine fueled with B20 biodiesel and an A123 Systems 12.9 kWh lithium-ion battery system. Two additional vehicle controllers were integrated for tailpipe emission control, CAN message integration, and power train hybridization control. Control laws for producing maximum fuel efficiency were implemented and include such features as engine auto-stop, regenerative braking and optimized engine operation. The engine operating range is confined to a high efficiency area that improves the overall combined engine and electric motor efficiency.

When heavy-duty truck emissions are expressed in distance-specific units (such as g/mile), the values may depend strongly on the nature of the test cycle or schedule. Prior studies have compared emissions gained using different schedules and have proposed techniques for translating emissions factor rates between schedules. This paper reviews emissions data from the 5-mode CARB HHDDT Schedule, UDDS Schedule, and a steady-state cycle (AC5080), with reference to each other. NOX and PM emissions are the two components of emissions which are reviewed. A heavy-duty chassis dynamometer was used for emissions characterization along with a full scale dilution tunnel. The vehicle test weights were simulated at 30,000 lbs, 56,000 lbs, and 66,000 lbs. For each vehicle, average data from one mode or cycle have been compared with average data for a different mode or cycle.

The California Air Resources Board (ARB) developed a Medium Heavy-Duty Truck (MHDT) schedule by selecting and joining microtrips from real-world MHDT. The MHDT consisted of three modes; namely, a Lower Speed Transient, a Higher Speed Transient, and a Cruise mode. The maximum speeds of these modes were 28.9, 58.2 and 66.0 mph, respectively. Each mode represented statistically selected truck behavior patterns in California. The MHDT is intended to be applied to emissions characterization of trucks (14,001 to 33,000lb gross vehicle weight) exercised on a chassis dynamometer. This paper presents the creation of the MHDT and an examination of repeatability of emissions data from MHDT driven through this schedule. Two trucks were procured to acquire data using the MHDT schedule. The first, a GMC truck with an 8.2-liter Isuzu engine and a standard transmission, was tested at laden weight (90% GVW, 17,550lb) and at unladen weight (50% GVW, 9,750lb).

Selective Catalytic Reduction (SCR) catalysts have been demonstrated as an effective solution for controlling NOx emissions from diesel engines. Typical 2013 Heavy Duty Diesel emission control systems include a DOC upstream of a catalyzed soot filter (CSF) which is followed by urea injection and the SCR sub-assembly. There is a strong desire to further increase the NOx conversion capability of such systems, which would enable additional fuel economy savings by allowing engines to be calibrated to higher engine-out NOx levels. One potential approach is to replace the CSF with a diesel particulate filter coated with SCR catalysts (SCRF® technology, hereafter referred to as SCR-DPF) while keeping the flow-through SCR elements downstream, which essentially increases the SCR volume in the after-treatment assembly without affecting the overall packaging.

In characterizing the emissions from mobile sources, it is essential that the vehicle be exercised in a way that reasonably represents typical in-use behavior. A heavy-heavy duty diesel truck (HHDDT) test schedule was developed from speed-time data gathered during two Air Resources Board-sponsored truck activity programs. The data were divided into four modes, termed Idle, Creep, Transient and Cruise Modes, in order of increasing speed. For the last three modes, speed-time schedules were created that represented all the data in that mode. Statistical parameters such as average speed, stops per unit distance, kinetic energy, maximum speed and acceleration and deceleration values were considered in arriving at these schedules. The schedules were evaluated using two Class 8 over-the-road tractors on a chassis dynamometer. Emissions were measured using a full-scale dilution tunnel, filtration for particulate matter (PM), and research grade analyzers for the gases.

Selective Catalytic Reduction (SCR) systems have been demonstrated as effective solutions for controlling NOx emissions from Heavy Duty diesel engines. Future HD diesel engines are being designed for higher engine out NOx to improve fuel economy, while discussions are in progress for tightening NOx emissions from HD engines post 2020. This will require increasingly higher NOx conversions across the emission control system and will challenge the current aftertreatment designs. Typical 2010/2013 Heavy Duty systems include a diesel oxidation catalyst (DOC) along with a catalyzed diesel particulate filter (CDPF) in addition to the SCR sub-assembly. For future aftertreatment designs, advanced technologies such as cold start concept (dCSC™) catalyst, SCR coated on filter (SCRF® hereafter referred to as SCR-DPF) and SCR coated on high porous flow through substrates can be utilized to achieve high NOx conversions, in combination with improved control strategies.

Selective Catalytic Reduction (SCR) systems have been demonstrated as effective solutions for controlling NOx emissions from Heavy Duty diesel engines. Future HD diesel engines are being designed for higher engine out NOx to improve fuel economy, which will require increasingly higher NOx conversion to meet emission regulations. For future aftertreatment designs, advanced technologies such as SCR coated on filter (SCRF®) and SCR coated on high porous flow through substrates can be utilized to achieve high NOx conversion. In this work, different options were evaluated for achieving high NOx conversion. First, high performance NOx control catalysts were designed by using SCRF unit followed by additional SCR on high porosity substrates. Second, different control strategies were evaluated to understand the effect of reductant dosing strategy and thermal management on NOx conversion. Tests were carried out on a HD engine under transient test cycles.

The EPA implemented the Urban Bus Retrofit/Rebuild (UBRR) Program for transit buses built before 1994 in an effort to lower the amount of PM emissions in densely populated urban areas. The objective of the program is to provide certified emission control technologies that reduce PM emissions from older buses by 25% or to below 0.1 g/bhp-hr. This paper reviews the development of a retrofit kit that has been certified under the UBRR program to meet the 0.1 g/bhp-hr PM emission requirements on DDC 6V92TA engines with both mechanical (MUI) and electronic (DDEC) fuel injection controls. The kit is a combination of specific and modified engine parts and a catalytic exhaust after-treatment device. The kit replaces existing parts with a new camshaft, a uniquely configured cylinder kit and specified turbocharger, blower and injector. For the MUI engines the cam timing, injector height and fuel modulator are set at specific values to achieve the lowest possible PM level.

Diesel oxidation catalyst and particulate filter technologies are well established and their applications are well known. However, there are certain limitations with both technologies due to their inherent technical characteristics. Both technologies get 75-90% reduction of HC and CO. A typical oxidation catalyst can be applied to almost any heavy duty diesel application and achieve 20 to 30% reduction in PM mass but no significant reduction in the number of PM particles. On the other hand, diesel particulate filters are very effective at removing >90% of the particles by mass and >99% by number. Unfortunately, passive DPF technology cannot be applied to all applications since the filter regeneration is limited by engine out NOx to PM ratio as well as exhaust temperature. For this reason, particulate filters can not universally be applied to older “dirtier” engines with high PM emissions.

Selective Catalytic Reduction (SCR) catalysts have been demonstrated as an effective solution for controlling NOx emissions from diesel engines. Typical 2010 Heavy-Duty systems include a DOC along with a catalyzed soot filter (CSF) in addition to the SCR sub-assembly. There is a strong desire to further increase the NOx conversion capability of such systems, to enable additional fuel economy savings by allowing engines to be calibrated to higher engine-out NOx levels. One potential approach is to replace the CSF with a diesel particulate filter coated with SCR catalysts (SCR-DPF) while keeping the flow-through SCR elements downstream, which essentially increases the SCR volume in the after-treatment assembly without affecting the overall packaging. In this work, a system consisting of SCR-DPF was evaluated in comparison to the DOC + CSF components from a commercial 2010 DOC + CSF + SCR system on an engine with the engine EGR on (standard engine-out NOx) and off (high engine-out NOx).