Onboard Measurements OfDiesel Engine Exhaust Gas Components

<div class="section abstract"><div class="htmlview paragraph">Amidst escalating climate change, the sustainability of internal combustion engine (ICE) vehicles, particularly in heavy transport, remains a critical challenge. Despite emission reductions from 1990 to 2020, ICEs, particularly diesel engines in Europe, continue to pose environmental challenges, notably in nitrogen oxide (NOx) emissions. This study proposes a novel solution to address the problem of NOx emissions by incorporating Air Cycle Technology’s (ACT) turboexpander into diesel engines. Acting as a second-stage compressor, intercooler, and expander, the turboexpander aims to lower intake air temperature, thereby mitigating NOx formation. The study utilizes a 4.4-l JCB-TCA-74 turbocharged diesel engine retrofitted with the ACT turboexpander as the experimental platform. The methodology involves using empirical formulae to calculate the key parameters of engine airflow for a standard turbocharged diesel engine followed by repeating the calculations for the same engine fitted with a turboexpander. Parameters including intake temperature, cylinder temperature, exhaust gas temperature, and NOx emissions are analyzed in depth and compared for both the engines. Initial calculations suggest that the turboexpander has the potential to reduce intake temperatures by up to 34°C, resulting in significant reductions in NOx emissions. These findings underscore the promising role of turboexpanders in enhancing the sustainability of diesel engines, urging further exploration across various engine types. As emissions standards tighten, the adoption of innovative solutions like turboexpanders could contribute to a cleaner and more sustainable future for the ICE.</div></div>

The features of the operation of the drillship-type vessels in special ecological regions of Northern Europe are considered. The main gap in the study of these systems is to determine the optimal degree of recirculation. The requirements of the International Maritime Organization for the emission of nitrogen oxides from the exhaust gases of marine diesel engines are given. The aim of the study is to determine the optimal degree of recirculation of exhaust gases of a 16V32 STX-MAN marine diesel. During the research, the optimal degree of exhaust gas recirculation varied in the range of 0–21%, the load on the diesel—in the range of 35–95% of the rated power. It was established that in this case, the emission of nitrogen oxides decreases up to 7.7–33.6%, the specific fuel consumption increases up to 0.2–3.5%. It was also found that the use of gas recirculation in the range of 18–21% at loads of 35–55% leads to a critical increase in exhaust gas temperature. It is advisable to use exhaust gas recirculation in the range of 6–15% to ensure the environmental friendliness of the operation of the drillships. In these modes, the maximum reduction in nitrogen oxide emissions is ensured with a minimum increase in specific fuel consumption. Future studies should be directed at the development of the criteria for the environmental stability of sea vessels.

A thermodynamic simulation is used to study the effects of oxygen-enriched intake air on the performance and nitrogen oxide (NO) emissions of a locomotive diesel engine. The parasitic power of the air separation membrane required to supply the oxygen-enriched air is also estimated. For a given constraint on peak cylinder pressure, the gross and net power outputs of an engine operating under different levels of oxygen enrichment are compared with those obtained when a high-boost turbocharged engine is used. A 4% increase in peak cylinder pressure can result in an increase in net engine power of approximately 13% when intake air with an oxygen content of 28% by volume is used and fuel injection timing is retarded by 4 degrees. When the engine is turbocharged to a higher inlet boost, the same increase in peak cylinder pressure improves power by only 4%. If part of the significantly higher exhaust enthalpies available as a result of oxygen enrichment are recovered, the power requirements of the air separator membrane can be met, resulting in substantial net power improvements. Oxygen enrichment reduces particulate and visible smoke emissions but increases NO emissions. However, a combination of retarded fuel injection timing and post-treatment of exhaust gases may be adequate to meet the locomotive diesel engine NO{sub x} standards. Exhaust gas after-treatment and heat recovery would be required to realize the full potential of oxygen enrichment. Economic analysis shows that oxygen-enrichment technology is economically feasible and provides high returns on investment. The study also indicates the strong influence of membrane parasitic requirements and exhaust energy recovery on economic benefits. To obtain an economic advantage while using a membrane with higher parasitic power requirements, it is necessary to recover a part of the exhaust energy.

The problem of air basin pollution of the World Ocean with harmful emissions from the exhaust gases of marine diesel engines is primarily associated with the creation of highly efficient technologies for the neutralization of nitrogen oxides NOx on exhaust gases from a diesel engine. Emissions of harmful substances from the combustion of marine fuels are limited by international atmospheric protection programs and the requirements of the International Maritime Organization (IMO). The requirements relate to almost all groups of harmful emissions in marine engines and the more stringent of them are primarily related to nitrogen oxides NOx and sulfur oxides SOx. To reduce harmful emissions from exhaust gases into the environment, scientists and world engine leaders use and suggest various methods for reducing the content of harmful substances in exhaust gases. The implementation of new standards in the areas of further improvement of the working process, the use of alternative fuels, fuel, and air additives, as well as selective catalytic reduction systems do not preclude further development of scientific research in the field of exhaust gas cleaning. One of the promising ways in environmentalizing marine internal combustion engines is the neutralization of harmful substances in exhaust gases through particular gas recirculation (EGR-technology). However, the use of such techniques conflicts with the engine's energy efficiency. In the work presented, the scheme-design solution of the exhaust gas recirculation system with using the heat of recirculation gases by an ejector refrigeration machine for cooling the air at the intake of ship's main engine is proposed. The effect of using the heat of recirculation gases for cooling the air at the intake of the engine is analyzed taking into account the changing climatic conditions for a particular vessel's route line. It is shown that the use of an ejector refrigeration machine reduces the air temperature at the entrance of the main engine by 5…15 ° С, which reduces the specific fuel consumption. This reduces emissions of harmful substances when the engine is running with recirculation of gases.

IMPROVMENT OF ENVIRONMENTAL PERFORMANCE TWO-STROKE DIESEL DURING OPERATION

Alternative sources of energy as marine fuels; the effect on the environment and the financial perspectives for a more sustainable future in the shipping industry

Characteristics of NOX and NH3 emissions from in-use heavy-duty diesel vehicles with various aftertreatment technologies in China

В даний час має місце інтенсивне посилення норм на токсичні викиди відпрацьованих газів суднових дизелів при плаванні суден в прибережних морських районах і на внутрішніх водних шляхах. Постійне зростання числа суден призводить до збільшення об’єму палива, що спалюється ними, а отже до збільшення викидів токсичних компонентів з відпрацьованими газами. В роботі проаналізовано зниження шкідливих викидів судновими дизелями за рахунок методу рециркуляції відпрацьованих газів.

The international shipping industry is facing increasingly stringent limitations on nitrogen oxide (NOx) emissions. New solutions for reducing NOx emitted by marine engines need to be investigated to find the best technology. Selective Catalytic Reduction (SCR) is an advanced active emissions control technology successfully used in automotive diesel engines; it could be applied to marine engines with ad-hoc solutions to integrate it in the exhaust of large engines. In this study, a commercial SCR was tested at the exhaust of a diesel engine in inlet gas conditions typical of a marine engine. The SCR system consisted of a custom monolith (provided by Hug-Engineering AG) that enabled seamless integration for a broad range of engine sizes; the active phases were V2O5 (3 wt%)-WO3 (7 wt%)-TiO2 (75 wt%). The monolith was studied at the laboratory scale for its in-depth chemical/physical characterization and by means of an intermediate-scale engine, reproducing the exhaust gas conditions of a full-scale marine engine. The system’s effectiveness in terms of NOx removal for the selected engine operating conditions was evaluated in a wide range of temperature and NOx emissions values and for different quantities of the reduction agent (AdBlue or ammonia) added to exhaust gases. The investigated technological solution resulted in efficient NOx emission control from a marine engine.

The nitrogen oxides (NOx) are prominent and harmful pollutants in the exhaust of diesel engines. The reduction of NOx to harmless products using catalysts is proved to be a remedy. The present study attempts to reduce NOx emissions in the exhaust of low heat rejection (LHR) diesel engine by catalytic reduction, using lanthanum ion exchanged zeolite (catalyst-A) and urea infused lanthanum ion exchanged zeolite (catalyst-B) under varied conditions . The effect of temperature of catalyst, space velocity, and void ratio on the reduction of NOx in the exhaust of the engines are also studied and compared with the conventional engine (CE) under identical conditions. The study showed a considerable reduction by 40-50% in NOx emissions.

<div class="htmlview paragraph">Copper ion-exchanged ZSM-5 zeolite catalyst, which reduces nitrogen oxides (NOx) in the presence of oxygen and hydrocarbons, was applied to actual diesel engine exhaust. Copper ion-exchanged ZSM-5 zeolite effectively reduced NOx by 25% in normal engine operation, and by 80% when hydrocarbons in the exhaust were increased. Water in the exhaust gas decreased the NOx reduction efficiency, but oxygen and sulfur appeared to have only a small effect. Maximum NOx reduction was observed at 400°C irrespective of hydrocarbon species, and did not decrease with space velocity up to values of 20,000 1/h.</div> <div class="htmlview paragraph">THE PURPOSE of this paper is to evaluate the possibilities and problems in catalytic reduction of NOx in actual diesel engine exhaust. Here, a copper ion-exchanged ZSM-5 zeolite (Cu-Z) catalyst was applied to diesel engine exhaust to examine the dependency of the NOx reduction efficiency on temperature and space velocity. The effects of oxygen, water and hydrocarbons were also examined.</div> <div class="htmlview paragraph">The reduction of NOx from diesel engine exhaust gas has become an important research topic in recent years. One of the obstacles to reducing NOx is that there is a tradeoff between NOx and particulates in diesel combustion. Although the overall level of these pollutants have been reduced through improvements in the combustion process, further reductions will be difficult to obtain because of this tradeoff effect.</div> <div class="htmlview paragraph">Recently, Iwamoto, et al. [<span class="xref">1</span>]-[<span class="xref">3</span>] and Held, et al. [<span class="xref">4</span>] have independently reported that copper ion-exchanged ZSM-5 zeolite (Cu-Z) is able to reduce NOx in the presence of oxygen, with hydrocarbons (HC) as the reducing agent. This catalyst has been shown to have a large reduction effect on synthesized gas which was modeled after diesel exhaust. Other catalysts such as proton-exchanged zeolite [51 and alumina [61J71 have been discovered to also be effective for reduction of NOx. These are all expected to be applicable as NOx reducing catalysts for diesel engines.</div>

For the two-stroke marine diesel engine, the action of exhaust valve has a significant impact on scavenging and combustion processes and ultimately affects the engine performances and emissions. In order to reduce nitrogen oxides (NOx) emissions of a two-stroke marine diesel engine, different exhaust valve lifts (EVLs) were achieved by computational fluid dynamics simulation method in this study. The NOx reduction effect and influence mechanism of EVL on a two-stroke marine diesel engine were investigated in detail. The results showed that the in-cylinder residual exhaust gas and the internal exhaust gas recirculation (EGR) rate gradually increased with the decreasing EVL. Although the total mass of charge enclosed in the cylinder did not change much, the composition changed gradually and the maximum internal EGR rate reached 13.17% in this study. The maximum compression pressure and combustion pressure both rose first and then decreased with the decreasing EVL. While the start of combustion and the maximum combustion temperature were basically unaffected by EVL, the indicated power of the engine was also not much impacted when the EVL was changed from increasing 10 mm to decreasing 20 mm. The indicated specific fuel consumption first declined slowly and then rose rapidly as the EVL reduction exceeded 20 mm. NOx emissions decreased monotonously with the decreasing EVL. The reduction of NOx formation rate and the amount of NOx formation mass mainly occurred at the middle and late stages of combustion for the downward moving of residual exhaust gas. NOx emissions were reduced by 12.57% without compromising other engine performances at medium-reduced EVL in this study. However, in order to further reduce NOx emissions at low EVLs, other measures may be needed to make the residual exhaust gas more evenly distributed during the initial stage of combustion.

The performance of natural zeolites in a catalytic converter to reduce the emission contents of diesel engine was studied in this research. Diesel engines are engines that use a high compression ratio to carry out a combustion process that will produce high contents of carbon monoxide (CO), nitrogen oxides (NOx), and sulfur oxide (SO2) in diesel engine exhaust gases. One solution to reduce the contents of exhaust gas compounds in diesel engines is to use catalytic converter technology. In this study, the catalytic converter used natural zeolite as an emission filter. The catalytic converter was designed in the form of a pipe made from iron plates and hollow balls that were used as natural zeolite holders. A diesel engine emission test was conducted using a gas analyzer with engine speed variations. The results show the highest reduction efficiency in the emission contents of diesel engine (carbon monoxide (CO), nitrogen oxides (NOx), and sulfur dioxide (SO2)) of 46.14%, 22.77%, and 90.56%, respectively.

The object of research is the process of ensuring the minimum level of carbon dioxide emissions when using selective catalytic reduction of exhaust gases from nitrogen oxides. It is noted that catalytic reduction systems provide the most effective purification of exhaust gases from nitrogen oxides. At the same time, due to the use of urea as a reagent in these systems, carbon dioxide emissions increase. This increases the greenhouse effect and reduces the energy efficiency of the ship. The research results presented in the work were carried out on a Gas Carrier class ship with a displacement of 127,645 tons with two main engines 5X72DF Hyundai-WinGD and three auxiliary engines 6H35DF Hyundai-HiMSEN. 5X72DF Hyundai-WinGD diesel engines were equipped with a high-pressure catalytic reduction system, 6H35DF Hyundai-HiMSEN diesel engines – with a low-pressure catalytic reduction system. It has been experimentally established that within the recommended range of urea supply to the catalytic reduction system of exhaust gases, there are optimal modes that ensure a minimal increase in carbon dioxide emissions while maintaining a high level of reduction in nitrogen oxide emissions. In these modes, the relative increase in carbon dioxide emissions does not exceed 2.3% for both types of diesel engines. Nitrogen oxide emissions for 5X72DF Hyundai-WinGD diesel engines do not exceed 3.3 g/(kW h) and do not exceed 2.4 g/(kW h) for 6H35DF Hyundai-HiMSEN diesel engines, which meets the requirements of Annex VI MARPOL. The relative reduction in nitrogen oxide emissions in these modes is 66.7–83.4% for 5X72DF Hyundai-WinGD diesel engines and 60.8–78.3% for 6H35DF Hyundai-HiMSEN diesel engines. The coincidence of the obtained values for the low-speed diesel engine 5X72DF Hyundai-WinGD and the medium-speed 6H35DF Hyundai-HiMSEN indicates the correctness of the research and the possibility of implementing their results on all types of diesel engines and catalytic reduction systems.

Emission regulations are steadily becoming more stringent, compelling researchers to adopt extra precautions to minimize the release of pollutants into the environment. For this purpose, many methods are employed by researchers. Among these, Water-Emulsified Fuels (WEFs) stand out as an effective solution for obtaining decrement on nitrogen oxide (NOx) and Particulate Matter (PM) emissions, concurrently. In this study, emulsion fuels were prepared using diesel, sunflower biodiesel, distilled water, and surfactants (Span 80 + Tween 80). The fuels are denoted as D (diesel), DW5 (93% diesel + 5% water + 2% surfactants), DW10 (88% diesel + 10% water + 2% surfactants), B (biodiesel), BW5 (93% biodiesel + 5% water + 2% surfactants), and BW10 (88% biodiesel + 10% water + 2% surfactants). Test fuels were prepared by stirring the emulsion mixture at a speed of 1500 rpm using a magnetic stirrer at room temperature for one hour, and the fuel properties were then specified. Finally, performance and emission tests were performed on a turbocharged, water-cooled, 4-stroke, and 4-cylinder diesel engine. WEFs led to decreased engine torque and brake power values, along with lowered carbon monoxide (CO) and nitrogen oxide (NOx) emissions. DW5 and DW10 reduced engine torque by 6.27% and 9.82%, and brake power by 6.49% and 10.31%, respectively, compared to D. Similarly, BW5 and BW10 decreased engine torque by 4.63% and 8.12%, and brake power by 4.73% and 8.38%, respectively, compared to B. Additionally, DW5 and DW10 fuels reduced CO emissions by 1.61% and 2.85%, and NOx emissions by 8% and 12.61%, respectively. BW5 and BW10 fuels lowered CO emissions by 1.56% and 3.67%, and NOx emissions by 3.87% and 10.47%, respectively.