Experimental Study of Oxygen-Enriched Diesel Combustion Using Simulated Exhaust Gas Recirculation

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Peter L. Perez ◽  
Andre L. Boehman
Keyword(s):  
Fuel Injection ◽  
Direct Injection ◽  
Injection Timing ◽  
Nox Emissions ◽  
Exhaust Gas ◽  
Operational Conditions ◽  
Rate Of Increase ◽  
Carbon Dioxide Co2 ◽  
Gas Recirculation ◽  
Co2 Addition

The techniques of design of experiments were applied to study the best operational conditions for oxygen-enriched combustion in a single-cylinder direct-injection diesel engine in order to reduce particulate matter (PM) emissions, with minimal deterioration in nitrogen oxide (NOx) emissions, by controlling fuel injection timing, carbon dioxide (CO2) and O2 volume fractions in intake air. The results showed that CO2 addition reduced average combustion temperatures and minimized the rate of increase in NOx emissions observed during oxygen-enriched conditions. It was also observed that oxygen enrichment minimized the deterioration in brake-specific fuel consumption and hydrocarbon and PM emissions that occurred at the highest level of CO2 addition.

Biodiesel Combustion and Emissions in Engines Using Modern Common-Rail Fuel Injection Systems

2008 ◽  
Author(s):  
Prashanth K. Karra ◽  
Matthias K. Veltman ◽  
Song-Charng Kong
Keyword(s):  
Fuel Injection ◽  
Injection Pressure ◽  
Exhaust Gas Recirculation ◽  
Common Rail ◽  
Injection System ◽  
Injection Timing ◽  
Fuel Injection System ◽  
Nox Emissions ◽  
Exhaust Gas ◽  
Gas Recirculation

This study performed experimental testing of a multi-cylinder diesel engine using different blends of biodiesel and diesel fuel. The engine used an electronically-controlled common-rail fuel injection system to achieve a high injection pressure. The operating parameters that were investigated included the injection pressure, injection timing, and exhaust gas recirculation rate. Results showed that biodiesel generally reduced soot emissions and increased NOx emissions. The increase in NOx emissions was not due to the injection timing shift when biodiesel was used because the present fuel injection system was able to give the same fuel injection timing. At high exhaust gas recirculation rates, emissions using regular diesel and 20% biodiesel blends are very similar while 100% biodiesel produces relatively different emission levels. Therefore, the increase in NOx emissions may not be a concern when 20% biodiesel blends are used with high exhaust gas recirculation rates in order to achieve low temperature combustion conditions.

Combustion of Hydrotreated Vegetable Oil in a Diesel Engine: Sensitivity to Split Injection Strategy and Exhaust Gas Recirculation

2020 ◽  
Author(s):  
Maciej Mikulski ◽  
Jacek Hunicz ◽  
Aneesh Vasudev ◽  
Arkadiusz Rybak ◽  
Michał Gęca
Keyword(s):  
Vegetable Oil ◽  
Diesel Fuel ◽  
Fuel Injection ◽  
Exhaust Gas Recirculation ◽  
Injection Timing ◽  
Nox Emissions ◽  
Exhaust Gas ◽  
Injection Strategy ◽  
Soot Emissions ◽  
Gas Recirculation

Abstract This work explores the potential to optimize advanced common-rail engines for operation with hydrotreated vegetable oil (HVO). The single-cylinder engine research focuses on adjusting the injection strategy and external exhaust gas recirculation (EGR) to achieve the optimum performance-emissions trade-off using HVO. The engine is operated at a fixed rotational speed of 2000 rpm and under constant load (net indicated mean effective pressure of 0.45 MPa). Split fuel-injection strategy is used: main injection timing is fixed but pilot injection is varied both in terms of timing and quantity. The engine tests, without turbocharging, are conducted under non-EGR conditions and using approximately 27% EGR rate. Results with HVO are compared with results when using diesel fuel. Within the constraints of a single, representative operating point, the results highlight that when using the factory map-based injection strategy, HVO offers soot emissions below 0.015 g/kWh, a 50% reduction when compared to diesel fuel. Nitrogen oxides (NOx) emissions at the same conditions are, however, 10% higher than for diesel fuel. That correlates with higher peak in-cylinder pressures and temperatures. Advancing the pilot HVO injection reduced NOx emissions to the level of the diesel baseline, and although soot emissions increased, they remained 25% lower than with diesel. Interestingly, the two tested fuels exhibited very different responses to EGR. Generally, at 27% EGR, HVO produced twice as much soot as diesel. The heat release analysis indicates this sensitivity to EGR stems from HVO’s higher cetane number causing faster auto-ignition, resulting in less premixed combustion and hence producing more soot. Generally, HVO offered more complete combustion than diesel fuel. Regardless of pilot fuel injection strategy, CO emission was reduced by approximately 50% with HVO for both EGR and non-EGR conditions. HVO also benefits emissions of unburned hydrocarbons, in terms of both total values and also unlegislated aldehydes and aromatics.

scholarly journals Particulate emissions from a highly boosted gasoline direct injection engine

2017 ◽  
Vol 19 (3) ◽  
pp. 347-359 ◽  
Author(s):  
Felix Leach ◽  
Richard Stone ◽  
Dave Richardson ◽  
Andrew Lewis ◽  
Sam Akehurst ◽  
...  
Keyword(s):  
Particle Number ◽  
Fuel Injection ◽  
Direct Injection ◽  
Injection Pressure ◽  
Back Pressure ◽  
Gasoline Direct Injection ◽  
Exhaust Gas ◽  
Fuel Injection Pressure ◽  
Gas Recirculation ◽  
Operating Points

Downsized, highly boosted, gasoline direct injection engines are becoming the preferred gasoline engine technology to ensure that increasingly stringent fuel economy and emissions legislation are met. The Ultraboost project engine is a 2.0-L in-line four-cylinder prototype engine, designed to have the same performance as a 5.0-L V8 naturally aspirated engine but with reduced fuel consumption. It is important to examine particle number emissions from such extremely highly boosted engines to ensure that they are capable of meeting current and future emissions legislation. The effect of such high boosting on particle number emissions is reported in this article for a variety of operating points and engine operating parameters. The effect of engine load, air–fuel ratio, fuel injection pressure, fuel injection timing, ignition timing, inlet air temperature, exhaust gas recirculation level, and exhaust back pressure has been investigated. It is shown that particle number emissions increase with increase in cooled, external exhaust gas recirculation and engine load, and decrease with increase in fuel injection pressure and inlet air temperature. Particle number emissions are shown to fall with increased exhaust back pressure, a key parameter for highly boosted engines. The effects of these parameters on the particle size distributions from the engine have also been evaluated. Significant changes to the particle size spectrum emitted from the engine are seen depending on the engine operating point. Operating points with a bias towards very small particle sizes were noted.

scholarly journals A research into a gasoline HCCI engine

2010 ◽  
Vol 140 (1) ◽  
pp. 3-13
Author(s):  
Jacek HUNICZ ◽  
Andrzej NIEWCZAS ◽  
Paweł KORDOS
Keyword(s):  
Internal Combustion Engines ◽  
Fuel Injection ◽  
Injection Timing ◽  
Exhaust Gas ◽  
Combustion Engines ◽  
Hcci Combustion ◽  
Permissible Range ◽  
Wide Range ◽  
Gas Recirculation ◽  
Direct Fuel Injection

Homogeneous charge compression ignition (HCCI) is nowadays a leading trend in the development of gasoline internal combustion engines. The application of this novel combustion system will allow to comply with future legislations concerning the exhaust emissions including carbon dioxide. This paper presents a design and implementation of a research engine with a direct fuel injection and the capability of HCCI combustion via an internal gas recirculation and a negative valves overlap (NVO). The technical approach used in the engine allowed an autonomous HCCI operation at variable loads and engine speeds without the need of a spark discharge. Experiments were conducted at a wide range of valve timings providing data which allowed an assessment of a volumetric efficiency and exhaust gas recirculation (EGR) rate. Permissible range of air excess coefficient, providing stable and repeatable operation has also been identified. The use of direct gasoline injection benefited in the improvement of the start of the combustion (SOC) and heat release rate control via the injection timing.

scholarly journals Investigation Into Reactivity Separation Between Direct Injected and Premixed Fuels in RCCI Combustion Mode

2019 ◽  
Author(s):  
Ziming Yan ◽  
Brian Gainey ◽  
Deivanayagam Hariharan ◽  
Benjamin Lawler
Keyword(s):  
Thermal Efficiency ◽  
Fuel Injection ◽  
Direct Injection ◽  
Combustion Efficiency ◽  
High Reactivity ◽  
Injection System ◽  
Injection Timing ◽  
Nox Emissions ◽  
Light Duty ◽  
Primary Reference

Abstract This experimental study focuses on the effects of the reactivity separation between the port injected fuel and the direct injection fuel, the amount of external-cooled exhaust gas recirculation (EGR), and the direct injection timing of the high reactivity fuel on Reactivity Controlled Compression Ignition (RCCI) combustion. The experiments were conducted on a light-duty, single-cylinder diesel engine with a production GM/Isuzu engine head and piston and a retrofitted port fuel injection system. The global charge-mass equivalence ratio, ϕ′, was fixed at 0.32 throughout all of the experiments. To investigate the effects of the fuel reactivity separation, different Primary Reference Fuels (PRF) were port injected, with the PRF number varying from 50 to 90. To investigate the effects of EGR, an EGR range of 0 to 55% was used. To investigate the effects of the injection timing, an injection timing window of −65 to −45 degrees ATDC was chosen. The results indicate that there are several tradeoffs. First, decreasing the port injected fuel reactivity (increasing the PRF number) delays combustion phasing, decreases the combustion efficiency by up to 9%, increases the gross indicated thermal efficiency up to 22%, enhances the combustion sensitivity to the direct injection timing, and slightly increases the UHC, CO, and NOx emissions. Second, increasing the EGR percentage delays combustion phasing, lowers the peak heat release rate, and lowers the NOx emissions. The combustion efficiency first increases and then decreases with EGR percentage for high reactivity fuels (low PRF number), but only decreases for low reactivity fuels. Finally, delaying the injection timing advances combustion phasing and increases the combustion efficiency, but decreases the gross indicated thermal efficiency and increases the NOx emissions. Across all of the experiments, delays in CA50 increase the gross indicated thermal efficiency and decrease the combustion efficiency, which represents an inherent tradeoff for RCCI combustion on a light-duty engine.

Characteristics of low temperature and low oxygen diesel combustion with ultra-high exhaust gas recirculation

2007 ◽  
Vol 8 (4) ◽  
pp. 365-378 ◽  
Author(s):  
H Ogawa ◽  
T Li ◽  
N Miyamoto
Keyword(s):  
Oxygen Concentration ◽  
Thermal Efficiency ◽  
Fuel Injection ◽  
Injection Pressure ◽  
Exhaust Gas Recirculation ◽  
Injection Timing ◽  
Exhaust Gas ◽  
Cent Oxygen ◽  
Low Oxygen ◽  
Gas Recirculation

Ultra-low NOx and smokeless operation at higher loads up to half of the rated torque is attempted with large rates of cold exhaust gas recirculation (EGR). NOx decreases below 6 ppm (0.05 g/kW h) and soot significantly increases when first decreasing the oxygen concentration to 16 per cent with cold EGR. However, after peaking at 12–14 per cent oxygen, soot then decreases sharply to essentially zero at 9–10 per cent oxygen while maintaining ultra-low NOx, regardless of fuel injection quantity and injection pressure. However, at higher loads, with the oxygen concentration below 9–10 per cent, the air-fuel ratio has to be over-rich to exceed half of the rated torque, and thermal efficiency, CO, and THC deteriorate significantly. As the EGR rate increases, exhaust gas emissions and thermal efficiency vary with the intake oxygen content rather than with the excess air ratio. Longer ignition delays due to either advancing or retarding the injection timing reduced the smoke emissions, but advancing the injection timing has the advantages of maintaining the thermal efficiency and preventing misfiring. A reduction in the compression ratio is effective to reduce the in-cylinder temperature and increase the ignition delay as well as to expand the smokeless combustion range in terms of EGR and i.m.e.p. (indicated mean effective pressure).

scholarly journals PM and NOX emissions amelioration from the combustion of diesel/ethanol-methanol blends applying exhaust gas recirculation (EGR)

2022 ◽  
Vol 961 (1) ◽  
pp. 012044
Author(s):  
Miqdam T. Chaichan ◽  
Noora S. Ekab ◽  
Mohammed A. Fayad ◽  
Hayder A. Dhahad
Keyword(s):  
Equivalence Ratio ◽  
Fuel Injection ◽  
Combustion Process ◽  
Exhaust Gas Recirculation ◽  
Operating Parameters ◽  
Injection Timing ◽  
Exhaust Gas ◽  
Oxygenated Fuel ◽  
Oxygenated Fuels ◽  
Gas Recirculation

Abstract The fuel injection timings, equivalence ratio (Ø) and exhaust gas recirculation are considered the most important parameters can effect on combustion process and lower exhaust emissions concentrations. The influence of 15% EGR technology and operating parameters (Ø and injection timing) on NOX emissions and particulate matter (PM) using oxygenated fuel (ethanol and methanol) blends were investigated in this experimental study. The results showed that the NOX emissions concentrations with increasing the equivalence ratio (Ø) and applied EGR for all fuels studied. Besides, the E10 and M10 decreased the PM concentrations compared to the diesel fuel under various equivalence ratios (Ø). The applied EGR increased the PM concentrations, but when combination of oxygenated fuels and EGR leading to the decrease in the PM formation. The NOX emissions concentrations decreased from the combined effect of EGR and oxygenated fuels by 16.8%, 22.91% and 29.5% from the combustion of diesel, M10 and E10, respectively, under various injection timings. It is indicated that NOX emissions decreased with retarded injection timings, while the PM decreased under advanced injection timings.

The Effects of Combination of EGR, Injection Retard and Injection Pressure on Emissions and Performance of Diesel Engine Fuelled With Jatropha Oil Methyl Ester

2006 ◽  
Author(s):  
J. G. Suryawanshi ◽  
N. V. Deshpande
Keyword(s):  
Methyl Ester ◽  
Fuel Injection ◽  
Injection Pressure ◽  
Good Effect ◽  
Injection Timing ◽  
Nox Emissions ◽  
Exhaust Gas ◽  
Jatropha Oil ◽  
And Performance ◽  
Fuel Injection Pressure

Retarded injection is used to control NOx emissions. Exhaust Gas Recirculation (EGR) is also an effective means of reducing NOx emissions from compression ignition engines. Higher fuel injection pressure may improve the combustion. EGR can be combined advantageously with other emission reducing measure such as retarded injection timing and performance improvement measures such as higher fuel injection pressure to have a good effect. The methyl ester of jatropha oil, known as biodiesel, is receiving increasing attention as an alternative fuel for diesel engines. Biodiesel is a non-toxic, biodegradable and renewable fuel with the potential to reduce engine exhaust emissions. The jatropha oil methyl ester was obtained through transesterification process. Various properties of the biodiesel thus developed were evaluated and compared in relation to that of conventional diesel oil. In the present investigation neat jatropha oil methyl ester (JME) as well as the blends of varying proportions of JME and diesel were used to run a CI engine with standard conditions (No EGR, No Injection Retard and 20 MPa Fuel Injection Pressure) and with combination of 20 % EGR, 4° retarded injection timing and 30 MPa fuel injection pressure. The addition of jatropha oil methyl ester (JME) to diesel fuel has significantly reduced HC, CO and smoke emissions but it increases the NOx emissions slightly with standard conditions. The NOx emission was drastically decreased with modified conditions. Further the smoke and unburned hydrocarbon emissions were decreased with modified conditions as compared to standard conditions. The brake thermal efficiency was improved with modified conditions at various loads. Exhaust gas temperatures were similar. The maximum cylinder gas pressure and heat release rate were lowered.

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