Technical Note: Exhaust emissions from an indirect injection dual-fuel engine

Author(s):  
G. H. Abd Alla ◽  
O. A. Badr ◽  
H. A. Soliman ◽  
Abd M. F. Rabbo

Diesel engines operating on gaseous fuels are commonly known as dual-fuel engines. In the present work, a single-cylinder, compression ignition, indirect injection research (Ricardo E6) engine has been installed at United Arab Emirates University for investigation of the exhaust emisssions when the engine is operating as a dual-fuel engine. The influence of changes in major operating and design parameters, such as the concentration of gaseous fuel in the cylinder charge, pilot fuel quantity, injection timing and intake temperature, on the production of exhaust emissions was investigated. Diesel fuel was used as the pilot fuel, while methane or propane was used as the main fuel which was inducted in the intake manifold and mixed with the intake air. The experimental investigations showed that the poor emissions at light loads can be improved significantly by increasing the concentration of gaseous fuel (total equivalence ratio), employing a large pilot fuel quantity, advancing the injection timing of the pilot fuel and increasing the intake temperature. It is demonstrated that, in general, any measure that tends to increase the size of the combustion regions within the overly lean cylinder charge will reduce markedly the concentrations of unburned hydro- carbons and carbon monoxide in the exhaust gases.

Author(s):  
Mohamed Y. E. Selim ◽  
M. S. Radwan ◽  
H. E. Saleh

The use of Jojoba Methyl Ester as a pilot fuel was investigated for almost the first time as a way to improve the performance of dual fuel engine running on natural gas or LPG at part load. The dual fuel engine used was Ricardo E6 variable compression diesel engine and it used either compressed natural gas (CNG) or liquefied petroleum gas (LPG) as the main fuel and Jojoba Methyl Ester as a pilot fuel. Diesel fuel was used as a reference fuel for the dual fuel engine results. During the experimental tests, the following have been measured: engine efficiency in terms of specific fuel consumption, brake power output, combustion noise in terms of maximum pressure rise rate and maximum pressure, exhaust emissions in terms of carbon monoxide and hydrocarbons, knocking limits in terms of maximum torque at onset of knocking, and cyclic data of 100 engine cycle in terms of maximum pressure and its pressure rise rate. The tests examined the following engine parameters: gaseous fuel type, engine speed and load, pilot fuel injection timing, pilot fuel mass and compression ratio. Results showed that using the Jojoba fuel with its improved properties has improved the dual fuel engine performance, reduced the combustion noise, extended knocking limits and reduced the cyclic variability of the combustion.


2020 ◽  
Vol 197 ◽  
pp. 06010
Author(s):  
Antonio Caricato ◽  
Antonio Paolo Carlucci ◽  
Antonio Ficarella ◽  
Luciano Strafella

In this paper, the effect of late injection on combustion and emission levels has been investigated on a single cylinder compression ignition engine operated in dual-fuel mode injecting methane along the intake duct and igniting it through a pilot fuel injected directly into the combustion chamber. During the tests, the amount of pilot fuel injected per cycle has been kept constant, while the amount of methane has been varied on three levels. Therefore, three levels of engine load have been tested, while speed has been kept constant equal to 1500rpm. Pilot injection pressure has been varied on three set points, namely 500, 1000 and 1500 bar. For each engine load and injection pressure, pilot injection timing has been swept on a very broad range of values, spanning from very advanced to very late values. The analysis of heat release rate indicates that MK-like conditions are established in dual-fuel mode with late pilot injection. In these conditions, pollutant species, and NOx levels in particular, are significantly reduced without penalization – and in several conditions with improvement – on fuel conversion efficiency.


2008 ◽  
Vol 12 (1) ◽  
pp. 151-156 ◽  
Author(s):  
Kapilan Nadar ◽  
Pratap Reddy ◽  
Rao Anjuri

In this work, an experimental work was carried out to compare the performance of biodiesels made from non edible mahua oil and edible gingili oil in dual fuel engine. A single cylinder diesel engine was modified to work in dual fuel mode and liquefied petroleum gas was used as primary fuel. Biodiesel was prepared by transesterification process and mahua oil methyl ester (MOME) and gingili oil methyl ester (GOME) were used as pilot fuels. The viscosity of MOME is slightly higher than GOME. The dual fuel engine runs smoothly with MOME and GOME. The test results show that the performance of the MOME is close to GOME, at the pilot fuel quantity of 0.45 kg/h and at the advanced injection timing of 30 deg bTDC. Also it is observed that the smoke, carbon monoxide and unburnt hydro carbon emissions of GOME lower than the MOME. But the GOME results in slightly higher NOx emissions. From the experimental results it is concluded that the biodiesel made from mahua oil can be used as a substitute for diesel in dual fuel engine.


Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5663 ◽  
Author(s):  
Mahantesh Marikatti ◽  
N. R. Banapurmath ◽  
V. S. Yaliwal ◽  
Y.H. Basavarajappa ◽  
Manzoore Elahi M Soudagar ◽  
...  

The present work is mapped to scrutinize the consequence of biodiesel and gaseous fuel properties, and their impact on compression-ignition (CI) engine combustion and emission characteristics in single and dual fuel operation. Biodiesel prepared from non-edible oil source derived from Thevetia peruviana belonging to the plant family of Apocynaceaeis. The fuel has been referred as methyl ester of Thevetia peruviana (METP) and adopted as pilot fuel for the effective combustion of compressed gaseous fuel of hydrogen. This investigation is an effort to augment the engine performance of a biodiesel-gaseous fueled diesel engine operated under varied engine parameters. Subsequently, consequences of gas flow rate, injection timing, gas entry type, and manifold gas injection on the modified dual-fuel engine using conventional mechanical fuel injections (CMFIS) for optimum engine performance were investigated. Fuel consumption, CO, UHC, and smoke formations are spotted to be less besides higher NOx emissions compared to CMFIS operation. The fuel burning features such as ignition delay, burning interval, and variation of pressure and heat release rates with crank angle are scrutinized and compared with base fuel. Sustained research in this direction can convey practical engine technology, concerning fuel combinations in the dual fuel mode, paving the way to alternatives which counter the continued fossil fuel utilization that has detrimental impacts on the climate.


Author(s):  
Jiafeng Sun ◽  
Joshua A. Bittle ◽  
Timothy J. Jacobs

Most studies comparing diesel/gasoline dual-fuel operation and single-fuel diesel operation in diesel engines center on time-averaged results. It seems few studies discuss differences in cyclic variability. Motivated by this, the present study evaluates the cyclic variability of combustion in both dual-fuel and single-fuel operations of a diesel engine. Steady-state tests were done on a medium duty diesel engine with conventional direct injection timings of diesel fuel into the cylinder at one speed and three loads. In addition to single-fuel (diesel) operation, dual-fuel (gasoline and diesel) operation was studied at increasing levels of gasoline fraction. Gasoline fuel is introduced via a fuel injector at a single location prior to the intake manifold (and EGR mixing location). Crank-angle resolved data including in-cylinder pressure and heat release rate obtained for around 150 consecutive cycles are used to assess cyclic variability. The sources of cyclic variability, namely the factors causing cyclic variability or influencing its magnitude, especially those related to cylinder charge amount and mixture preparation, are analyzed. Fuel spray penetration and cyclic variability of cylinder charging, overall A/F ratio, and fuel injection timing, tend to increase cyclic variability of combustion in dual-fuel operation. On the other hand, fuel type and fuel spray droplet size tend to increase cyclic variability in single-fuel operation. The cyclic variability in dual-fuel operation in this study is more serious than that in single-fuel operation, in terms of magnitude, indicated by metrics chosen to quantify it. Most measures of cyclic variability increase consistently with increasing gasoline fraction. Variations of gasoline amount and possibly gasoline low temperature heat release cause higher combustion variation in dual-fuel operation primarily by affecting premixed burning. Statistical methods such as probability density function, autocorrelation coefficient, return map, and symbol sequence statistics methods are used to check determinism. In general, the parameters studied do not show strong determinism, which suggests other parameters must be identified to establish determinism or the system is inherently stochastic. Regardless, dominant sequences and optimal sequence lengths can be identified.


2008 ◽  
Vol 33 (6) ◽  
pp. 1314-1323 ◽  
Author(s):  
Cenk Sayin ◽  
Kadir Uslu ◽  
Mustafa Canakci

Author(s):  
N Saravanan ◽  
G Nagarajan

Hydrogen is receiving considerable attention as an alternative fuel to replace the rapidly depleting petroleum-based fuels. Its clean burning characteristics help to meet the stringent emission norms. In this experimental investigation a single-cylinder diesel engine was converted to operate in hydrogen—diesel dual-fuel mode. Hydrogen was injected in the intake manifold and the diesel was injected directly inside the cylinder. The injection timing and the injection duration of hydrogen were optimized on the basis of performance and emissions. Best results were obtained with hydrogen injection at gas exchange top dead centre with an injection duration of 30° crank angle. The flowrate of hydrogen was optimized as 7.5l/min with optimized injection timing and duration. The optimized exhaust gas recirculation (EGR) flowrate was 20 per cent at 75 per cent load. The optimized timings were chosen on the basis of performance, emission, and combustion characteristics. The EGR technique was adopted in the hydrogen—diesel dual-fuel mode by varying the EGR flowrate from 0 per cent to 25 per cent in steps of 5 per cent. The maximum quantity of exhaust gases recycled during the test was 25 per cent (up to 75 per cent load); beyond that unstable combustion was observed with an increase in smoke. The brake thermal efficiency with 20 per cent EGR decreases by 9 per cent compared with diesel. The nitrogen oxide (NO x) emission in hydrogen manifold injection decreases by threefold with 20 per cent EGR operation at full load. The NO x emission tends to reduce drastically with increase in the EGR percentage at all load conditions owing to the increase in heat capacity of the exhaust gases. The smoke decreases by 80 per cent in the dual-fuel operation compared with diesel at 75 per cent load.


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