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

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.

Author(s):  
Par Neiburger

Liberator Engine Company, LLC designs, develops and produces alternative fuel engines for vehicles around the globe. The Company’s 6.0 Liter Liberator™ gaseous fuels engine will have the ability to operate on Compressed Natural Gas, Liquefied Natural Gas or Liquid Propane Gas: clean, domestic, economical fuels. The Liberator engine will target OEM on road vehicles, as well as off road applications. The Liberator engine is also an excellent choice for the repower of existing diesel vehicles. The 6.0L Liberator™ engine will serve as a replacement engine for vehicle currently operating on a Cummins 5.9L diesel engine or Mercedes diesel 6.0L engine. Paper published with permission.


2014 ◽  
Vol 660 ◽  
pp. 442-446 ◽  
Author(s):  
Devarajan Ramasamy ◽  
Z.A Zainal ◽  
R.A. Bakar ◽  
K. Kadirgama

Vehicle efficiency relates to pollutants and cost savings in third world countries. In term of subcompact cars, the vehicle characteristics are governed by the engine for alternative fuels. The main focus of this paper was to evaluate a sub compact car engine for its performance and burn rate of gasoline and Compressed Natural Gas (CNG). A bi-fuel sequential system was used to do this evaluation. Measurements of engine speed, torque and fuel were done on an eddy current dynamometer, while measurements or in-cylinder pressure, crank angle and spark were analyzed from results taken by data acquisition system. The emissions readings were also compared from an emission analyzer. The results were analyzed for burn rate based on the first law of thermodynamic. The comparison shows a drop of 18.6% was seen for the power, brake specific fuel consumption (BSFC) loss was 7% and efficiency loss was at 17.3% in average for all engine speed. Pressure analysis shows peak pressure dropped by 16%. Burn rate shows why CNG had a slower burning speed on the small engine. The engine speed of 4000 rpm at Maximum Brake Torque (MBT) produced the most nearest results to gasoline.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xin Wang ◽  
Qian Zhang ◽  
Fangjie Liu ◽  
Yifan Jin ◽  
Xin Li

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.


Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1342
Author(s):  
Van Chien Pham ◽  
Jae-Hyuk Choi ◽  
Beom-Seok Rho ◽  
Jun-Soo Kim ◽  
Kyunam Park ◽  
...  

This paper presents research on the combustion and emission characteristics of a four-stroke Natural gas–Diesel dual-fuel marine engine at full load. The AVL FIRE R2018a (AVL List GmbH, Graz, Austria) simulation software was used to conduct three-dimensional simulations of the combustion process and emission formations inside the engine cylinder in both diesel and dual-fuel mode to analyze the in-cylinder pressure, temperature, and emission characteristics. The simulation results were then compared and showed a good agreement with the measured values reported in the engine’s shop test technical data. The simulation results showed reductions in the in-cylinder pressure and temperature peaks by 1.7% and 6.75%, while NO, soot, CO, and CO2 emissions were reduced up to 96%, 96%, 86%, and 15.9%, respectively, in the dual-fuel mode in comparison with the diesel mode. The results also show better and more uniform combustion at the late stage of the combustions inside the cylinder when operating the engine in the dual-fuel mode. Analyzing the emission characteristics and the engine performance when the injection timing varies shows that, operating the engine in the dual-fuel mode with an injection timing of 12 crank angle degrees before the top dead center is the best solution to reduce emissions while keeping the optimal engine power.


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