Formation of Nitrogen Dioxide and Formaldehyde in a Medium Duty Diesel Engine With Oxygenated Fuels

2020 ◽  
Author(s):  
Denis Notheis ◽  
Uwe Wagner ◽  
Amin Velji ◽  
Thomas Koch
Keyword(s):  
Diesel Engine ◽  
Nitrogen Oxides ◽  
Nitrogen Dioxide ◽  
Diesel Fuel ◽  
Oxygen Radicals ◽  
Injection Timing ◽  
Boost Pressure ◽  
Fuel Ratio ◽  
Oxygenated Fuels ◽  
Operating Points

Abstract For modern Diesel aftertreatment systems the ratio of nitrogen dioxide (NO2) to nitrogen oxides emissions (NOx) is of great importance for the conversion of total NOx especially at low loads and low engine out exhaust temperatures. As known from previous studies the relative air-fuel ratio and so the increase of oxygen has a major impact on the in-cylinder formation of NO2. As the focus lies mainly on increasing the relative air-fuel ratio by increasing the boost pressure the influence of bounded oxygen in oxygenated fuels is not yet fully understood and is therefore in the focus of this papers. Bounded oxygen offers the potential to release oxygen radicals, which can increase NO2 formation from nitrogen monoxide (NO) at higher pressures according to the principle of Le Chatelier. At low pressures, however, released oxygen radicals can also lead to a reduction of NO2. Additionally, concerning the in-cylinder formation of NO2, the formation of formaldehyde (HCHO) is focused in this investigation, too. Especially for the oxygenated fuel like OME3–5 which can be interpreted as a compound of formaldehyde molecules the HCHO emission might increase. Although HCHO has not yet been regulated for vehicles, its carcinogenic properties require its reduction as far as possible. In this paper, investigations are presented which were carried out on a single-cylinder Diesel engine with different oxygenated fuels such as oxymethylene ether compounds (OME3–5) and 2-ethoxyethyl ether (2-EEE) and blends of these components with conventional Diesel fuel. The relevant exhaust gas components were measured using different analysis method for high accuracy and mutual validation. To analyze the effects of the fuel composition on nitrogen dioxide and formaldehyde formation the fuels are compared with pure Diesel fuel operation. Several operating points were investigated together while varying engine parameters such as relative air-fuel ratio, EGR rate, injection timing and injection pressure in a one-factor-time parameter study. Additionally, at a low load operating point a Design of Experiments (DoE) study was done to see the statistical impact and the main influencing parameters of the formation of NO2 and HCHO. Furthermore, other typical Diesel emissions like particulates, carbon monoxide and the total nitrogen oxides are investigated and compared. The investigations show an inconsistent behavior at different operating points for NO2. In most operating points a decrease of NO2 is visible, which was attributed to a decrease of the total NOx emission. Especially at higher relative air-fuel ratios and so high charge pressures the potential of oxygenated fuels to increase the NO2 to NOx ratio becomes apparent. Due to the very low particulates emissions which can be achieved with OME3–5 fuel, no restriction on low relative air/fuel ratios and higher EGR rates regarding the particulate emissions (smoke limit) exists. The HCHO emissions show different behavior in these restriction zones. At partial load, high EGR rates and low relative air-fuel ratios, HCHO emissions increase. In contrast, when the load is increased and the stoichiometric conditions are reached, the HCHO emissions decrease.

scholarly journals Low-Speed Marine Diesel Engine Modeling for NOx Prediction in Exhaust Gases

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4442
Author(s):  
Branko Lalić ◽  
Andrijana Poljak ◽  
Gojmir Radica ◽  
Antonija Mišura
Keyword(s):  
Diesel Engine ◽  
Nitrogen Oxides ◽  
Nitrogen Dioxide ◽  
Nitrogen Oxide ◽  
Fuel Consumption ◽  
Compression Ratio ◽  
Fuel Injection ◽  
Nitrogen Monoxide ◽  
Exhaust Emissions ◽  
Injection Timing

Knowing the process of generating exhaust emissions and the determination of influential parameters are important factors in improving two-stroke slow-speed marine engines, particularly for further reductions in fuel consumption and stringent regulations on the limitation of nitrogen oxide emissions. In this article, a model of a marine low-speed two-stroke diesel engine has been developed. Experimental and numerical analyses of the nitrogen monoxide formations were carried out. When measuring the concentration of nitrogen oxides in the exhaust emissions, the amount of nitrogen dioxide (NO2) is usually measured, because nitrogen monoxide is very unstable, and due to the large amount of oxygen in the exhaust gases, it is rapidly converted into nitrogen dioxide and its amount is included in the total emission of nitrogen oxides. In this paper, the most significant parameters for the formation of nitrogen monoxide have been determined. Model validation was performed based on measured combustion pressures, engine power, and concentrations of nitrogen oxides at 50% and 75% of maximum continuous engine load. The possibilities of fuel consumption optimization and reduction in nitrogen monoxide emissions by correcting the injection timing and changing the compression ratio were examined. An engine model was developed, based on measured combustion pressures and scavenging air flow, to be used on board by marine engineers for rapid analyses and determining changes in the concentration of nitrogen oxides in exhaust emissions. The amount of nitrogen oxide in exhaust emissions is influenced by the relevant features described in this paper: fuel injection timing and engine compression ratio. The presented methodology provides a basis for further research about the simultaneous impact of changing the injection timing and compression ratio, exhaust valve opening and closing times, as well as the impact of multiple fuel injection to reduce consumption and maintain exhaust emissions within the permissible limits.

A phenomenological combustion analysis of a dual-fuel natural-gas diesel engine

2016 ◽  
Vol 231 (1) ◽  
pp. 66-83 ◽  
Author(s):  
Shuonan Xu ◽  
David Anderson ◽  
Mark Hoffman ◽  
Robert Prucka ◽  
Zoran Filipi
Keyword(s):  
Diesel Engine ◽  
Natural Gas ◽  
Heat Release ◽  
Diesel Fuel ◽  
Fuel Injection ◽  
Dual Fuel ◽  
Injection Timing ◽  
Heavy Duty ◽  
Engine System ◽  
Wiebe Function

Energy security concerns and an abundant supply of natural gas in the USA provide the impetus for engine designers to consider alternative gaseous fuels in the existing engines. The dual-fuel natural-gas diesel engine concept is attractive because of the minimal design changes, the ability to preserve a high compression ratio of the baseline diesel, and the lack of range anxiety. However, the increased complexity of a dual-fuel engine poses challenges, including the knock limit at a high load, the combustion instability at a low load, and the transient response of an engine with directly injected diesel fuel and port fuel injection of compressed natural gas upstream of the intake manifold. Predictive simulations of the complete engine system are an invaluable tool for investigations of these conditions and development of dual-fuel control strategies. This paper presents the development of a phenomenological combustion model of a heavy-duty dual-fuel engine, aided by insights from experimental data. Heat release analysis is carried out first, using the cylinder pressure data acquired with both diesel-only and dual-fuel (diesel and natural gas) combustion over a wide operating range. A diesel injection timing correlation based on the injector solenoid valve pulse widths is developed, enabling the diesel fuel start of injection to be detected without extra sensors on the fuel injection cam. The experimental heat release trends are obtained with a hybrid triple-Wiebe function for both diesel-only operation and dual-fuel operation. The ignition delay period of dual-fuel operation is examined and estimated with a predictive correlation using the concept of a pseudo-diesel equivalence ratio. A four-stage combustion mechanism is discussed, and it is shown that a triple-Wiebe function has the ability to represent all stages of dual-fuel combustion. This creates a critical building block for modeling a heavy-duty dual-fuel turbocharged engine system.

OPTIMIZATION OF GAS-DIESEL ENGINE REGULATION AS A METHOD OF IMPROVING ITS ECOLOGICAL CHARACTERISTICS

2021 ◽  
pp. 28-32
Author(s):  
VALERIY L. CHUMAKOV ◽  
Keyword(s):  
Carbon Monoxide ◽  
Diesel Engine ◽  
Nitrogen Oxides ◽  
Diesel Fuel ◽  
Hydrocarbon Fuel ◽  
Load Range ◽  
Engine Operation ◽  
Exhaust Gases ◽  
Wide Range ◽  
Diesel Cycle

The paper shows some ways to improve the environmental characteristics of a diesel engine using gaseous hydrocarbon fuel and operating the engine in a gas-diesel cycle mode. Some possibilities to reduce toxic components of exhaust gases in a gas-diesel engine operating on liquefi ed propane-butane mixtures have been studied. Experiments carried out in a wide range of load from 10 to 100% and speed from 1400 to 2000 rpm showed that the gas-diesel engine provides a suffi ciently high level of diesel fuel replacement with gas hydrocarbon fuel. The authors indicate some eff ective ways to reduce the toxicity of exhaust gases. The engine power should be adjusted by the simultaneous supply of fuel, gas and throttling the air charge in the intake manifold. This method enriches the fi rst combusting portions to reduce nitrogen oxides and maintains the depletion of the main charge within the fl ammability limits of the gas-air charge to reduce carbon monoxide and hydrocarbons. The authors found that when the engine operates in a gas-diesel cycle mode, the power change provides a decrease in nitrogen oxide emissions of gas-diesel fuel only due to gas supply in almost the entire load range as compared to the pure diesel. At high loads (more than 80%) stable engine operation is ensured up to 90% of diesel fuel replaced by gas. Even at 10% of diesel fuel used the concentration of nitrogen oxides decreases by at least 15…20% as compared with a diesel engine in the entire load range. However, there is an increased emission of hydrocarbons and carbon monoxide in the exhaust gases. Further experimental studies have shown that optimization of the gas diesel regulation can reduce the mass emission of nitrogen oxides contained in exhaust gases in 2…3 times and greatly reduce the emission of incomplete combustion products – carbon monoxide and hydrocarbons.

Spray and Combustion Characteristics of Biodiesel∕Diesel Blended Fuel in a Direct Injection Common-Rail Diesel Engine

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Hyun Kyu Suh ◽  
Hyun Gu Roh ◽  
Chang Sik Lee
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Direct Injection ◽  
Injection Rate ◽  
Combustion Characteristics ◽  
Biodiesel Fuel ◽  
Injection Timing ◽  
Pilot Injection ◽  
Blended Fuel ◽  
Conventional Diesel Fuel

The aim of this work is to investigate the effect of the blending ratio and pilot injection on the spray and combustion characteristics of biodiesel fuel and compare these factors with those of diesel fuel in a direct injection common-rail diesel engine. In order to study the factors influencing the spray and combustion characteristics of biodiesel fuel, experiments involving exhaust emissions and engine performance were conducted at various biodiesel blending ratios and injection conditions for engine operating conditions. The macroscopic and microscopic spray characteristics of biodiesel fuel, such as injection rate, split injection effect, spray tip penetration, droplet diameter, and axial velocity distribution, were compared with the results from conventional diesel fuel. For biodiesel blended fuel, it was revealed that a higher injection pressure is needed to achieve the same injection rate at a higher blending ratio. The spray tip penetration of biodiesel fuel was similar to that of diesel. The atomization characteristics of biodiesel show that it has higher Sauter mean diameter and lower spray velocity than conventional diesel fuel due to high viscosity and surface tension. The peak combustion pressures of diesel and blending fuel increased with advanced injection timing and the combustion pressure of biodiesel fuel is higher than that of diesel fuel. As the pilot injection timing is retarded to 15deg of BTDC that is closed by the top dead center, the dissimilarities of diesel and blending fuels combustion pressure are reduced. It was found that the pilot injection enhanced the deteriorated spray and combustion characteristics of biodiesel fuel caused by different physical properties of the fuel.

Investigations on Low Heat Rejection Diesel Engine With Crude Jatropha Oil as an Alternate Fuel

2002 ◽  
Author(s):  
M. V. S. Murali Krishna ◽  
C. M. Vara Prasad ◽  
Tandur Rajashekar ◽  
Supriya Tiwari ◽  
T. Sujani
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Injection Pressure ◽  
High Viscosity ◽  
Injection Timing ◽  
Jatropha Oil ◽  
Heat Rejection ◽  
Reduction Of Nox ◽  
Conventional Diesel Fuel ◽  
Diesel Operation

Jatropha oil, a non-edible vegetable oil shows a greater potential for replacing conventional diesel fuel quite effectively, as its properties are compatible to that of diesel fuel. But low volatility and high viscosity of jatropha oil call for hot combustion chamber, which is provided by a low heat rejection diesel engine with threaded air gap piston and liner with superni-90 inserts. The performance of the engine with jatropha oil is obtained with different versions of the engine such as conventional engine and insulated engine at normal and preheat condition of the oil, with varying injection pressure and timing and compared to the engine with pure diesel operation at recommended injection pressure and timing. Increase of thermal efficiency of 18% and reduction of NOx levels by 5% are observed at optimized injection timing and at higher injection pressure with insulated engine at preheat condition of jatropha oil in comparison with pure diesel operation on conventional engine.

A Study on Adaptability of the Engine Control Module of an Existing Heavy Duty Diesel Engine to Optimize the Engine Performance With F-T Diesel Fuel

2007 ◽  
Author(s):  
Praveen Kandulapati ◽  
Chuen-Sen Lin ◽  
Dennis Witmer ◽  
Thomas Johnson ◽  
Jack Schmid ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Load Condition ◽  
Engine Performance ◽  
Injection Timing ◽  
Heavy Duty ◽  
Synthetic Fuels ◽  
Control Module ◽  
Heavy Duty Diesel Engine ◽  
Heavy Duty Diesel

Synthetic fuels produced from non-petroleum based feedstocks can effectively replace the depleting petroleum based conventional fuels while significantly reducing the emissions. The zero sulfur content and the near zero percentage of aromatics in the synthetic fuels make them promising clean fuels to meet the upcoming emissions regulations. However due to their significantly different properties when compared to the conventional fuels; the existing engines must be tested extensively to study their performance with the new fuels. This paper reports a detailed in-cylinder pressure measurement based study made on adaptability of the engine control module (ECM) of a modern heavy duty diesel engine to optimize the engine performance with the F-T diesel fuel. During this study, the F-T and Conventional diesel fuels were tested at different loads and various injection timing changes made with respect to the manufacturer setting. Results from these tests showed that the ECM used significantly different injection timings for the two fuels in the process of optimizing the engine performance. For the same power output the ECM used a 2° advance in the injection timing with respect to the manufacturer setting at the full load and 1° retard at the no load condition. While the injection timings used by the ECM were same for both the fuels at the 50% load condition. However, a necessity for further changes in the control strategies used by the ECM were observed to get the expected advantages with the F-T fuels.

Experimental investigations on combustion of jatropha methyl ester in a turbocharged direct-injection diesel engine

2008 ◽  
Vol 222 (10) ◽  
pp. 1865-1877 ◽  
Author(s):  
K Anand ◽  
R P Sharma ◽  
P S Mehta
Keyword(s):  
Diesel Engine ◽  
Methyl Ester ◽  
Diesel Fuel ◽  
Fuel Injection ◽  
Peak Pressure ◽  
Direct Injection ◽  
Pressure Rise ◽  
Experimental Investigations ◽  
Injection Timing ◽  
Gas Temperature

Suitability of vegetable oil as an alternative to diesel fuel in compression ignition engines has become attractive, and research in this area has gained momentum because of concerns on energy security, high oil prices, and increased emphasis on clean environment. The experimental work reported here has been carried out on a turbocharged direct-injection multicylinder truck diesel engine using diesel fuel and jatropha methyl ester (JME)-diesel blends. The results of the experimental investigation indicate that an increase in JME quantity in the blend slightly advances the dynamic fuel injection timing and lowers the ignition delay compared with the diesel fuel. A maximum rise in peak pressure limited to 6.5 per cent is observed for fuel blends up to 40 per cent JME for part-load (up to about 50 per cent load) operations. However, for a higher-JME blend, the peak pressures decrease at higher loads remained within 4.5 per cent. With increasing proportion of JME in the blend, the peak pressure occurrence slightly advances and the maximum rate of pressure rise, combustion duration, and exhaust gas temperature decrease by 9 per cent, 15 per cent and 17 per cent respectively. Although the changes in brake thermal efficiencies for 20 per cent and 40 per cent JME blends compared with diesel fuel remain insignificant, the 60 per cent JME blend showed about 2.7 per cent improvement in the brake thermal efficiency. In general, it is observed that the overall performance and combustion characteristics of the engine do not alter significantly for 20 per cent and 40 per cent JME blends but show an improvement over diesel performance when fuelled with 60 per cent JME blend.

Exhaust Emissions of an Off-Road Diesel Engine Driven With a Blend of Diesel Fuel and Mustard Seed Oil

2003 ◽  
Author(s):  
Seppo A. Niemi ◽  
Juha M. Tyrva¨inen ◽  
Mika J. Laure´n ◽  
Va¨ino¨ O. K. Laiho
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Seed Oil ◽  
Particle Number ◽  
Exhaust Emissions ◽  
Mustard Seed ◽  
Injection Timing ◽  
Nox Emissions ◽  
Fuel Blend ◽  
Full Load

In the near future, crude oil based fuels must little by little be replaced by biofuels both in the region of the European Union (EU) and in the United States. Bearing this in mind, a Finnish-made off-road diesel engine was tested with a biofuel-diesel fuel blend in the Internal Combustion Engine (ICE) Laboratory of Turku Polytechnic, Finland. The biofuel was cold-pressed mustard seed oil (MSO). The engine operation, performance and exhaust emissions were investigated using a blend of 30 mass-% MSO and 70 mass-% diesel fuel oil (DFO). The injection timing of the engine was retarded considerably in order to reduce NOx emissions drastically. The main target was then to find out, whether the blended oxygen containing MSO would speed up the combustion so that the particulate matter (PM) emissions would remain unchanged or even decrease despite the injection retardation. As secondary tasks of the study, the NOx readings of the CLD and FTIR analyzers were compared, and exhaust contents of unregulated compounds were determined. Retarding the injection timing resulted in a significant decrease of NOx emissions, but in an increase in smoke, as expected. At retarded timing, the NOx emissions remained almost unchanged, but the amount of smoke decreased when the engine was run with the fuel blend instead of DFO. At retarded timing at rated speed, the number of ultra-fine particles decreased, but the amount of large particles increased with DFO at full load. At 10% load, however, the particle number increased in the entire particle size range due to retardation. At both loads, the use of the fuel blend slightly reduced larger particles, whereas the number of small particles somewhat increased. At full load at an intermediate speed of 1500 rpm, the PM results were very similar to those obtained at rated speed. At 10% load with DFO, however, the injection retardation led to a higher number of larger particles, the smaller particles being at almost an unchanged level. With the fuel blend, the particle number was now higher within almost the whole particle diameter range than with DFO. Considerably higher NO2 contents were usually detected with FTIR than with CLD. The shape of the NOx result curves were rather similar independent of which one of the analyzers was used for measurements. The NOx contents were, however, generally some ten ppms higher with FTIR. The exhaust contents of unregulated compounds were usually low.

scholarly journals Investigation of the impact of injection timing and pressure on emissions characteristics and smoke/soot emissions in diesel engine fuelling with soybean fuel

2021 ◽  
Vol 9 (2) ◽  
Author(s):  
Mohammed A. Fayad ◽  
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Fuel Combustion ◽  
Pollutant Emissions ◽  
Injection Timing ◽  
Injection Strategy ◽  
Renewable Fuel ◽  
Soybean Biodiesel ◽  
Soot Emissions ◽  
The Impact

Engine injection strategy and renewable fuel both can improve nitrogen oxides (NOX) and smoke/soot emissions in a common-rail compression ignition (CI) diesel engine. The effects of different postinjection (PI) timings (15, 30, and 45) after top dead center (aTDC) and injection pressures (550 and 650 bar) on pollutant emissions and smoke/soot emissions were investigated for combustion of a renewable fuel (soybean biodiesel). The results showed that the levels of carbon monoxide (CO), hydrocarbons (HCs), and NOX are reduced from the combustion of soybean biodiesel compared to the diesel fuel combustion for different injection strategy. Besides, NOX emission is clearly reduced with retarded PI timing, especially at 45°. It is found that the increasing injection pressure reduced gaseous emissions for both fuels. The combination between biodiesel fuel and injection strategy can provide meaningful improvements in pollutant emissions, as well as enhance the exhaust temperature compared to the diesel fuel. With biodiesel fueling, smoke/soot emissions were reduced from biodiesel combustion (by 19.7%) under different fuel injection timings and pressures rather than from the diesel fuel combustion (by 12.2%).

scholarly journals A research on fuelling a truck diesel engine with hydrogen

2019 ◽  
Vol 112 ◽  
pp. 01011
Author(s):  
Nikolaos Cristian Nutu ◽  
Constantin Pana ◽  
Niculae Negurescu ◽  
Alexandru Cernat ◽  
Dinu Fuiorescu ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Nitrogen Oxides ◽  
Diesel Fuel ◽  
Nitrogen Monoxide ◽  
Experimental Investigations ◽  
Test Bed ◽  
Smoke Emission ◽  
Emission Level ◽  
Theoretical Investigations ◽  
Semi Empirical

The paper presents experimental and theoretical investigations results of a truck diesel engine fuelled with diesel fuel and hydrogen by diesel-gas method. The purpose of the paper is to reduce the level of the nitrogen oxides emission level and to improve the overall performances of the engine. The use of hydrogen represents a suitable method to reduce the classic fuels consumption, maintaining the energetic performances of the engine. The test bed situated in the Thermotechnics, Engines, Thermal Equipments and Refrigeration Instalations Department of University Politechnica of Bucharest was adapted for hydrogen fuelling of the truck diesel engine. The engine used for investigations is a turbocharged 10.2 l truck diesel engine which run at 1450 rpm and 40% engine load. By hydrogen fuelling if the investigated diesel engine a decrease has been achieved in the nitrogen oxides emission level and in the smoke emission level. Also the break energetic specific consumption decreased compared to the standard diesel engine. The theoretical investigations presented in tha paper are based on a semi-empirical corellation, used to simulate the nitrogen monoxide emission formation. The results of the experimental investigations confirm de viability of hydrogen as an alternative fuel for the diesel engine.

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