scholarly journals Experimental investigation on n-butanol/methyl oleate dual fuel RCCI combustion in a single cylinder engine at high-load condition

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xin Wang ◽  
Qian Zhang ◽  
Fangjie Liu ◽  
Yifan Jin ◽  
Xin Li
Keyword(s):  
Methyl Oleate ◽  
Direct Injection ◽  
Dual Fuel ◽  
Pilot Injection ◽  
Cylinder Pressure ◽  
Engine Load ◽  
Single Cylinder ◽  
Single Cylinder Engine ◽  
Test Conditions ◽  
Hc Emissions

AbstractReactivity controlled compression ignition (RCCI) engines have a high thermal efficiency as well as low emissions of soot and nitrogen oxides (NOx). However, there is a conflict between combustion stability and harmful emissions at high engine load. Therefore, this work presented a novel approach for regulating n-butanol/methyl oleate dual fuel RCCI at high engine load in attaining lower pollutant emissions while maintaining stable combustion and avoiding excessive in-cylinder pressure. The tests were conducted on a single cylinder engine under rated speed and 90% full load. In this study, n-butanol was selected as a low-reactivity fuel for port injection, and n-butanol/methyl oleate blended fuel was used for in-cylinder direct injection. Combustion and emission characteristics of the engine were first investigated with varied ratios of n-butanol port injection (PFI) and direct injection (DI). Results showed that as the ratio of n-butanol PFI and DI rose, the peak cylinder pressure and heat release rate increased, while NOx and soot emissions reduced, and carbon monoxide (CO) and hydrocarbon (HC) emissions increased under most test conditions. When RNBPI = 40% and RNBDI = 20%, the soot and NOx emissions of the engine were near the lowest values of all test conditions, yet the peak in-cylinder pressure and fuel consumption could not increase significantly. Therefore, the possibility of optimizing the combustion process and lowering emissions by adjusting the pilot injection strategy was investigated utilizing these fuel injection ratios. The results revealed that with an appropriate pilot injection ratio and interval, the peak in-cylinder pressure and NOx emission were definitely reduced, while soot, CO, and HC emissions did not significantly increase.

Comparative assessment of engine vibration, combustion, performance and emission characteristics between single and twin-cylinder diesel engines in unifuel and dual-fuel mode

2021 ◽  
pp. 1-39
Author(s):  
Akash Chandrabhan Chandekar ◽  
Sushmita Deka ◽  
Biplab K. Debnath ◽  
Ramesh Babu Pallekonda
Keyword(s):  
Natural Gas ◽  
Alternative Fuels ◽  
Load Condition ◽  
Alternative Fuel ◽  
Dual Fuel ◽  
Cylinder Pressure ◽  
Compressed Natural Gas ◽  
Single Cylinder ◽  
Engine Vibration ◽  
Single Cylinder Engine

Abstract The persistent efforts among the researchers are being done to reduce emissions by the exploration of different alternative fuels. The application of alternative fuel is also found to influence engine vibration. The present study explores the potential connection between the change of the engine operating parameters and the engine vibration pattern. The objective is to analyse the effect of alternative fuel on engine vibration and performance. The experiments are performed on two different engines of single cylinder and twin-cylinder variants at the load range of 0 to 34Nm, with steps of 6.8Nm and at the constant speed of 1500rpm. The single cylinder engine, fuelled with only diesel mode, is tested at two compression ratios of 16.5 and 17.5. While, the twin-cylinder engine with a constant compression ratio of 16.5, is tested at both diesel unifuel and diesel-compressed natural gas dual-fuel modes. Further, in dual-fuel mode, tests are conducted with compressed natural gas substitutions of 40%, 60% and 80% for given loads and speed. The engine vibration signatures are measured in terms of root mean square acceleration, representing the amplitude of vibration. The combustion parameters considered are cylinder pressure, rate of pressure rise, heat release rate and ignition delay. At higher loads, the vibration amplitude increases along with the cylinder pressure. The maximum peak cylinder pressure of 95bar is found in the case of the single cylinder engine at the highest load condition that also produced a peak vibration of 3219m/s2.

An Experimental Investigation on Engine Exhaust Emissions of a Low Heat Rejection (Mullite Coated) Single Cylinder Diesel Engine

2012 ◽  
Vol 588-589 ◽  
pp. 344-348
Author(s):  
Pankaj N. Shrirao ◽  
Parvezalam I. Shaikh ◽  
Farazuddin Zafaruddin ◽  
A.N. Pawar
Keyword(s):  
Diesel Engine ◽  
Direct Injection ◽  
Gas Temperature ◽  
Engine Exhaust ◽  
Engine Load ◽  
Single Cylinder ◽  
Full Load ◽  
Average Decrease ◽  
Piston Crown ◽  
Hc Emissions

Tests were performed on a single cylinder, four stroke, direct injection, diesel engine whose piston crown, cylinder head and valves were coated with a 0.5 mm thickness of 3Al2O3.2SiO2(mullite) (Al2O3= 60%, SiO2= 40%) over a 150 µm thickness of NiCrAlY bond coat. The working conditions for the conventional engine (without coating) and LHR (mullite coated) engine were kept exactly same to ensure a comparison between the two configurations of the engine. This paper is intended to emphasis on emission characteristics of diesel engine with and without mullite coating under identical conditions. Tests were carried out at same operational constraints i.e. air-fuel ratio and engine speed conditions for both conventional engine (without coating) and LHR (mullite coated) engines. The results showed that, there was as much as29.41% and 24.35% decreasing on CO and HC emissions respectively for LHR (mullite coated) engine compared to conventional engine (without coating) at full load. The average decrease in smoke density in the LHR engine compared with the conventional engine was 13.82 % for full engine load. However, there was as much as 20% increasing on NOx emission for LHR engine compared to conventional engine at full load. Also the results revealed that, there was as much as 22% increasing on exhaust gas temperature for LHR engine compared to conventional engine at full engine load.

Analysis of the relationship between particle number and fuel cutoff in a single-cylinder gasoline direct injection engine

2020 ◽  
Vol 234 (13) ◽  
pp. 3001-3010
Author(s):  
Jingeun Song ◽  
Mingi Choi
Keyword(s):  
Particle Number ◽  
Direct Injection ◽  
Gasoline Direct Injection ◽  
Injection Timing ◽  
Cylinder Pressure ◽  
Engine Load ◽  
Direct Injection Engine ◽  
Single Cylinder ◽  
Gasoline Direct Injection Engine ◽  
Load Change

This study investigates the effects of fuel cutoff on particle number in a single-cylinder wall-guided gasoline direct injection engine. Various durations of fuel cutoff and change in load and engine stop were tested, and the in-cylinder pressure, particle number, and NO x emissions were measured. The change in in-cylinder temperature during combustion stop was calculated using the in-cylinder pressure and the ideal gas law. Experimental results showed that as the fuel cutoff duration increased, the particle number increased significantly when combustion resumed. For the injection timing before top dead center 330°, the particle number, which was 600 × 103 #/cm3 under the continuous combustion condition, increased to 6700 × 103 #/cm3 after 30 s of fuel cutoff. Both the fuel cutoff and engine stop showed enormous amount of particle number when combustion restarted. A major factor that increased particle number was the temperature reduction of piston during the combustion stop. The peak in-cylinder temperature decreased by 38 K during 30 s of motoring, which was induced by the temperature drop of the piston. Therefore, in terms of particulate emissions, it is more advantageous to lower the engine load than to stop combustion: the piston surface remains hot during load reduction. In addition, it is recommended to change the engine load slowly to reduce the particle number emissions. In this study, the rapid load change from indicated mean effective pressure of 0.25 to 0.55 MPa showed 7% higher particle number emissions than the gentle load change. On the contrary, NO x was reduced because none was generated during combustion stop. However, the fuel cutoff would increase NO x in gasoline vehicles because the oxygen in the unburned air would significantly reduce the conversion efficiency of a three-way catalytic converter. It is especially worth investigating the reason for the increase in emissions because it is easy to think that all kinds of emissions will be reduced if fuel is not burned.

scholarly journals Assessment of late pilot injection effect in dual-fuel combustion

2020 ◽  
Vol 197 ◽  
pp. 06010
Author(s):  
Antonio Caricato ◽  
Antonio Paolo Carlucci ◽  
Antonio Ficarella ◽  
Luciano Strafella
Keyword(s):  
Injection Pressure ◽  
Dual Fuel ◽  
Injection Timing ◽  
Pilot Injection ◽  
Compression Ignition Engine ◽  
Engine Load ◽  
Pilot Fuel ◽  
Dual Fuel Combustion ◽  
Cylinder Compression ◽  
Injection Effect

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.

Optimization of High Pressure Direct Injection Micro-Pilot As a Retrofit Technology for Conventional Dual Fuel Engines

2019 ◽  
Author(s):  
Greg Beshouri ◽  
Gerry Fischer
Keyword(s):  
High Pressure ◽  
Performance Optimization ◽  
Experimental Testing ◽  
Direct Injection ◽  
Dual Fuel ◽  
Injection Timing ◽  
Test Results ◽  
Fuel Gas ◽  
Single Cylinder ◽  
Dual Fuel Engines

Abstract In the late 1980’s Enterprise Engine Company performed a single cylinder test of micro-pilot high pressure direct injection as a retrofit technology for conventional dual fuel engines. While that testing demonstrated a number of benefits for this technology, non-technical considerations led to the use of low pressure Pre-Combustion Chamber (PCC) micro-pilot technology as the retrofit technology instead. Thirty years later, when the automotive components of the PCC micro-pilot system were no longer available, the opportunity again arose to test the capabilities of an off the shelf high pressure direct injection micro-pilot system as a retrofit technology for a conventional dual fuel engine. Single cylinder and full engine testing of the high pressure direct injection micro-pilot injection confirmed the results of the 1980’s testing. The test results also corroborated modern analytical and experimental testing of high pressure pilot technology. In particular, the interaction between the diesel pilot and primary fuel gas charge is very complex and sometimes counterintuitive. Likewise performance optimization requires careful balance of injection timing, injection quantity and fuel gas air/fuel ratio. Even then, exhaust gas methane emissions remain counterintuitive. This paper reviews modern single cylinder and full engine test results focusing on optimization parameters for high pressure direct injection micro-pilot for retrofit and new engine applications.

A Computational Investigation of the Impact of Multiple Injection Strategies on Combustion Efficiency in Diesel-Natural Gas Dual Fuel Low Temperature Combustion Engine

2019 ◽  
Author(s):  
Lorenzo Bartolucci ◽  
Stefano Cordiner ◽  
Vincenzo Mulone ◽  
Sundar R. Krishnan ◽  
Kalyan K. Srinivasan
Keyword(s):  
Experimental Data ◽  
Low Temperature ◽  
Natural Gas ◽  
Combustion Efficiency ◽  
Dual Fuel ◽  
Pilot Injection ◽  
Low Temperature Combustion ◽  
Single Cylinder ◽  
Temperature Combustion ◽  
The Impact

Abstract Dual fuel diesel-methane low temperature combustion (LTC) has been investigated by various research groups, showing high potential for emissions reduction (especially oxides of nitrogen (NOx) and particulate matter (PM)) without adversely affecting fuel conversion efficiency in comparison with conventional diesel combustion. However, when operated at low load conditions, dual fuel LTC typically exhibit poor combustion efficiencies. This behavior is mainly due to low bulk gas temperatures under lean conditions, resulting in unacceptably high carbon monoxide (CO) and unburned hydrocarbon (UHC) emissions. A feasible and rather innovative solution may be to split the pilot injection of liquid fuel into two injection pulses, with the second pilot injection supporting the methane combustion once the process is initiated by the first one. In this work, diesel-methane dual fuel LTC is investigated numerically in a single-cylinder heavy-duty engine operating at 5 bar brake mean effective pressure (BMEP) at 85% and 75% percentage of energy substitution (PES) by methane (taken as a natural gas surrogate). A multidimensional model is first validated in comparison with experimental data obtained on the same single-cylinder engine for early single pilot diesel injection at 310 CAD and 500 bar rail pressure. With the single pilot injection case as baseline, the effects of multiple pilot injections and different rail pressures on combustion emissions are investigated, again showing good agreement with experimental data. Apparent heat release rate and cylinder pressure histories as well as combustion efficiency trends are correctly captured by the numerical model. Results prove that higher rail pressures yield reductions of HC and CO by 90% and 75%, respectively, at the expense of NOx emissions, which increase by ∼30% from baseline. Furthermore, it is shown that post-injection during the expansion stroke does not support the stable development of the combustion front as the combustion process is confined close to the diesel spray core.

Investigation on the combustion noise of a pilot-ignited direct-injection natural-gas engine

2016 ◽  
Vol 230 (14) ◽  
pp. 1942-1957 ◽  
Author(s):  
Menghan Li ◽  
Qiang Zhang ◽  
Guoxiang Li
Keyword(s):  
Natural Gas ◽  
Direct Injection ◽  
Injection Pressure ◽  
Pressure Level ◽  
Combustion Noise ◽  
Injection Timing ◽  
Cylinder Pressure ◽  
Engine Load ◽  
Gas Engine ◽  
Natural Gas Engine

In this paper, the effects of the injection timing, the injection pressure and the engine load on the combustion noise of a pilot-ignited direct-injection natural-gas engine were explored by analysing the separate components of the in-cylinder pressure. The results suggested that retarding the injection timing and reducing the injection pressure are effective ways of controlling the combustion noise. This can be attributed to the promoted burning rate at advanced injection timings and to the increased injection pressure. However, the effect of the engine load seems to be less obvious, although the resonance pressure level appears to increase with increasing engine load; the estimated combustion noise shows a decreasing tendency.

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