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Abstract The selective catalytic reduction (SCR) of nitrogen oxides seems to be the most promising technique to meet prospective emission regulations of diesel-driven commercial vehicles. In the case of developing cost-effective catalytic converters with comparably high activity, selectivity, and resistance against aging, ion-exchanged zeolites play a major role. This study presents, firstly, a brief literature review and subsequently a discussion of an extensive conversion analysis of exemplary Cu/ and Fe/zeolites, as well as a homogeneous admixture of both. The aging stages of SCR catalysts deserve particular attention in this study. In addition, the aging condition of the diesel oxidation catalyst (DOC) was analyzed, which influences the nitrogen dioxide (NO2) formation, because the NO2/nitrogen oxides (NOx) ratio upstream from the SCR converter could be identified as a key factor for low temperature NOx conversion.

An innovative Diffusive Air Jet (DAJ) Combustion Chamber concept has been introduced in the present work. The DAJ Combustion Chamber design is based on the study of rate of heat release (ROHR) curve and its correlation with emission generation. The objective is to lower the trade-off between NOx and soot without sacrificing fuel economy of Direct Injection (DI) diesel engine. DAJ Combustion Chamber modifies ROHR curve to the desired one so that it lowers engine out emissions. To study its effect, a large bore, six cylinder engine with mechanical fuel injection system has been used. Three dimensional simulation software is used for the model calibration of basic reentrant cavity. Local emissions and ROHR curve have been studied using reentrant cavity shape. It has been modified to DAJ Combustion Chamber using Air Jet Chambers (AJCs). AJCs are positioned in the three dimensional model in such a way that they affect local in-cylinder emissions.

The Selective Catalytic Reduction (SCR) system installed on the exhaust line is currently widely used on Diesel heavy-duty trucks and it is considered a promising technique for light and medium duty trucks, large passenger cars and off-highway vehicles, to fulfill future emission legislation. Some vehicles of these last categories, equipped with SCR, have been already put on the market, not only in the US, where the emission legislation on Diesel vehicles is more restrictive, but also in Europe, demonstrating to be already compliant with the upcoming Euro 6. Moreover, new and more stringent emission regulations and homologation cycles are being proposed all over the world, with a consequent rapidly increasing interest for this technology. As a matter of fact, a physical model of the Diesel Exhaust Fluid (DEF) supply system is very useful, not only during the product development phase, but also for the implementation of the on-board real-time controller.

Global warming due to exhaust emissions, rapid depletion of crude oil, and strict carbon control legislation has forced researchers to search biofuels as substitute for petroleum diesel fuels. Biodiesel is a renewable and oxygenated fuel. It is free from sulfur, non-toxic and a biodegradable. The different non-edible vegetable oils such as Algae, Karanja and Jatropha could be used to produce biodiesel. Biodiesel is a green fuel with an exception that it emits 15-20% more NOx as compared to diesel fuel. The emissions of nanoparticles are more hazardous to human health. The nanoparticles emission of biodiesel must be measured according to the new strict regulations. The engine performance and the lower emission characteristics, except for NOx emission, for Algae, Karanja and Jatropha oil biodiesels are similar to those of diesel fuel.

This paper discusses the development of an all speed governed diesel-natural gas dual fuel engine for agricultural farm tractor. A 45 hp, 2.9 liters diesel-natural gas dual fuel engine with a novel closed loop secondary fuel injection system was developed. A frugal approach without any modification of the base mechanical diesel fuel injection system was followed. This approach helped to minimize the cost impact, while meeting performance and emissions at par with neat diesel operation. Additional cost on gas injection system is redeemed by cost savings on diesel fuel. The dual fuel technology developed by Mahindra & Mahindra Ltd., substitutes on an average approximately 40% of diesel with compressed natural gas, meeting the TREM III A emission norms for dual fuel while meeting all application requirements. The governing performance of the tractor was found to be superior than base diesel tractor.

Investigating the impact of Gasoline fuel on diesel engine performance and emission is very important for military heavy- duty combat vehicles. Gasoline has great potential as alternative fuel due to rapid depletion of petroleum reserves and stringent emission legislations, under multi fuel strategy program for military heavy- duty combat vehicle. There is a known torque, horsepower and fuel economy penalty associated with the operation of a diesel engine with Gasoline fuel. On the other hand, experimental studies have suggested that Gasoline fuel has the potential for lowering exhaust emissions, especially NOx, CO, CO2, HC and particulate matter as compared to diesel fuel. Recent emission legislations also restrict the total number of nano particles emitted in addition to particulate matter, which has adverse health impact.

Problems of reducing emissions of harmful substances and fuel consumption of the engine are interrelated, since they are mainly determined by the work process. Measures aimed to reducing fuel consumption cause changes, often upwards, toxic compound formation. The fuel and environmental criterion is proposed taking into account the engine operating conditions for a reasonable choice of technical solutions for the comprehensive improvement of fuel economy and toxic level indicators of the exhaust gases. This criterion allows assessing the effectiveness of solutions to improve combustion efficiency, the use of alternative fuels, exhaust gas aftertreatment systems, and other measures.

The winter of 2013-2014 provided an opportunity to operate off-road vehicles in cold weather for extended time as part of a vehicle/tier 4 diesel engine validation program. An unexpected area of study was the performance of high efficiency, on engine, fuel filters during continuous vehicle operation in cold weather. During the program we observed unexpected premature fuel filter plugging as indicated by an increase in pressure drop across the filter while in service. Field and laboratory testing was completed at John Deere and Donaldson to understand the cause of filter plugging. Although conditions were found where winter fuel additives could cause plugging of high efficiency filters, premature filter plugging occurred even when testing with #1 diesel fuel. This fuel contained no additives and was used at temperatures well above its cloud point.

In recent years urea selective catalytic reduction (SCR) has become the principal method of NOx abatement within heavy duty (HD) diesel exhaust systems; however, with upcoming applications demanding NOx reduction efficiencies of above 96 % on engines producing upwards of 10 g·kWh−1 NOx, future diesel exhaust fluid (DEF) dosing systems will be required to operate stably at significantly increased dosing rates. Developing a dosing system capable of meeting the increased performance requirements demands an improved understanding of how DEF sprays interact with changing exhaust flows. This study has investigated four production systems representing a diverse range of dosing strategies in order to determine how performance is influenced by spray structure and identify promising strategies for further development. The construction of an optically accessible hot-air flow rig has enabled visualisation of DEF injection into flows representative of HD diesel exhaust conditions.

This study was aimed at experimentally investigating the impact of diesel/natural gas (NG) dual-fuel retrofitting onto gaseous emissions emitted by i) legacy, model year (MY) 2005 heavy-duty engines with cooled EGR and no after-treatment system, and ii) a latest technology engine equipped with DPF and urea-SCR after-treatment systems that is compliant with 2010 US-EPA emissions standards. In particular, two different dual-fuel conversion kits were evaluated in this study with pure methane (CH4) being used as surrogate for natural gas. Experiments were conducted on an engine dynamometer over a 13-mode steady-state test cycle as well as the transient FTP required for engine certification while gaseous emissions were sampled through a CVS system. Tailpipe NOx emissions were observed at a comparable level for diesel and diesel/CH4 dual-fuel operation for the 2010 compliant engine downstream the SCR.

To meet future emission targets, it becomes increasingly important to optimize the synergy between engine and aftertreatment system. By using an integrated control approach minimal fluid (fuel and DEF) consumption is targeted within the constraints of emission legislation during real-world operation. In such concept, the on-line availability of engine-out NOx emission is crucial. Here, the use of a Virtual NOx sensor can be of great added-value. Virtual sensing enables more direct and robust emission control allowing, for example, engine-out NOx determination during conditions in which the hardware sensor is not available, such as cold start conditions. Furthermore, with use of the virtual sensor, the engine control strategy can be directly based on NOx emission data, resulting in reduced response time and improved transient emission control. This paper presents the development and on-line implementation of a Virtual NOx sensor, using in-cylinder pressure as main input.

La1-xAxNi1-yByO3 nanostructured perovskite-type oxides catalysts (where A = Na, K, Rb and B = Cu; x = 0, 0.2 and y = 0, 0.05, 0.1), also supporting 2% in weight of gold, were prepared via the so-called “Solution Combustion Synthesis (SCS)” method, and characterized by means of XRD, BET, FESEM-EDS and TEM analyses. The performance of these catalysts towards the simultaneous oxidation of soot and CO was evaluated. The 2 wt.% Au-La0.8K0.2Ni0.9Cu0.1O3 showed the best performance with a peak carbon combustion temperature of 367 °C and the half conversion of CO reached at 141 °C. The same nanostructured catalyst, deposited by in situ SCS directly over a SiC filter and tested on real diesel exhaust gases, fully confirmed the encouraging results obtained on the powder catalyst.

Abstract The current publication considers several methodologies to minimize tailpipe (TP) nitrogen oxides (NOx) emissions during cold start operation. A standard, 2019 aftertreatment design of diesel oxidation catalyst (DOC), diesel particulate filter (DPF), and selective catalytic reduction (SCR)/ammonia oxidation catalyst (AMOX) was used as the baseline. Cold start NOx conversion and TP NOx emissions improvements were measured when a larger SCR, dual diesel exhaust fluid (DEF) dosing, and an electric heater were added to the exhaust configuration. Additional improvements were achieved by an improved cold start combustion mode was developed.

Abstract Particulate Matter (PM) is one of the most sought-after exhaust emissions from Heavy-Duty Diesel Engines (HDDEs) to reduce. Several regulations in Europe and North America have led the way in drastically reducing PM of both on-road and off-road engines through stringent adoption of Diesel Particulate Filters (DPFs) and advanced combustion techniques. The effects of these advanced aftertreatment systems were studied using standardized testing procedures and equipment. While PM is defined as a “single” criteria pollutant, its complex structure entails several chemical compounds and molecules, displaying a whole spectrum of particle sizes. In addition, the morphology of some volatile compounds is shown to be affected by the interaction with background air during exhaust dilution and cooling.

Considerable development effort has shown that conventional diesel engine lubricating oil specifications do not define the needs for acceptable injector life in methanol-fueled, two-stroke cycle diesel engines. A cooperative program was undertaken to formulate an engine oil-fuel additive system which was aimed at improving performance with methanol fueling. The performance feature of greatest concern was injector tip plugging. A Taguchi matrix using a 100 hour engine test was designed around an engine oil formulation which had performed well in a 500 hour engine test using a simulated urban bus cycle. Parameters investigated included: detergent level and type, dispersant choice, and zinc dithiophosphate level. In addition, the influence of a supplemental fuel additive was assessed. Analysis of the Taguchi Matrix data shows the fuel additive to have the most dramatic beneficial influence on maintaining injector performance.

Diesel powered vehicles are characterized by two distinctives, of particulate, sensed by sight, and odor, sensed by smell. Dramatically reducing these distinctives would result in a “clean diesel”. A joint program of Yellow Freight System, Inc. (YFS) and the author's employer (DCI) has addressed one distinctive (particulate) and has resulted in an exhaust filtering system for the diesel forklift trucks YFS use to move freight at their terminals. This paper covers design, installation, and testing of the system to filter the particulate emissions emanating from these forklifts. The filters, designed to operate for one programmed maintenance (PM) cycle, are then cleaned in off-board equipment and returned to service for another cycle. All filter materials utilized are compatible with the 200°C normal maximum operating temperature, although short excursions to 260°C have not been detrimental.

Commercial vehicles carry more than 10 billion tons of goods - approximately 70 percent of all freight shipped and travel over 450 billion miles each year in the United States. These vehicles are the exclusive mode of delivery in over 75 percent of U.S. communities. Such utilization and dependency demand commercial vehicles be reliable, durable, and cost effective. The heart of these commercial vehicles (Classes 3-8) is the diesel engine. The widespread use of the diesel engine can be attributed to its reliability, durability, and cost effectiveness. However, the 2007 and 2010 EPA emissions regulations are creating significant challenges for diesel-powered commercial vehicles. Engine and vehicle manufacturers must strike a balance between emissions, performance, and affordability. A consequence of the evolution of the diesel engine to meet the increasingly stringent emissions regulations is that more effort to accommodate the associated changes is driven to the vehicle manufacturers.

The effect of SCR on nanoparticle emissions has been a subject for some recent diesel particle emission related studies. In this study, the effect of after-treatment (DOC and SCR) on particle emissions was studied with a heavy-duty off-road diesel engine (emission level stage 3b with an SCR). A special “transient cold test cycle” (TCTC) was designed to describe the SCR system operation at low exhaust gas temperatures. The particle instrumentation made it possible to measure on-line the particle number concentration, particle size distribution and chemical composition of particles. The largest particle number concentrations were measured after the exhaust manifold. The exhaust after-treatment was observed to reduce the total particle number concentration by 82.5% with the DOC and 95.7% with the DOC+SCR.

Due to the rising price of crude oil, biofuel is being considered as a global alternative for fossil fuels to reduce the emission of greenhouse gases. Diesel blended with bio fuel is currently being widely adopted in many countries. The Taiwanese government has been enforcing the adoption of B2 since 2010. However, there have remained consistent concerns about engine durability related to the use of biofuel, especially regarding after-treatment systems. A selective catalytic reduction system (SCR) has been utilized recently to reduce NOX emission in order to meet the Euro IV and V emission standards. To evaluate the impact of biodiesel on the durability of engines equipped with the SCR system, a long-term testing program was organized for the purposes of this study. The results can be used as a reference for the development of marketing promotion strategies as well as government policies in Taiwan.

Abstract With ever tightening emission standards, the automotive industry is continuously seeking novel ways to improve the aftertreatment system (ATS). Exhaust treatment systems using diesel emission fluid (DEF), in conjunction with selective catalytic reduction (SCR) and diesel oxidation converters (DOC), have been gaining popularity in the heavy equipment industry. Spraying DEF (mixture of urea and water) into the exhaust flow can neutralize harmful NOx gases into N2 and H2O. Design of ATSs focuses on high evaporation rate and uniform mixing of ammonia at the entrance to the SCR catalyst. This study applied support vector regressor (SVR), a machine learning (ML) method to a database of computational fluid dynamics (CFD) simulations to develop a highly efficient mixer with high heat exchange characteristics. Over 500 mixer designs were evaluated using CFD and were then used to train the SVR model.