scholarly journals Numerical simulations of dual fuel combustion in a heavy duty compression ignition engine

2015 ◽  
Vol 163 (4) ◽  
pp. 47-56
Author(s):  
Łukasz KAPUSTA

In this study dual fuel direct injection was studied in terms of utilizing in compression ignition engines gaseous fuels with high octane number which are stored in liquid form, specifically liquid propane. Due to the fact that propane is not as much knock-resistant as natural gas, instead of conventional dual fuel system a system based on simultaneous direct injection of two fuel was selected as the most promissing one. Dual fuel operation was compared with pure diesel operation. The performed simulations showed huge potential of dual fuel system for burning light hydrocarbons in heavy duty compression ignition engines. However, further secondary fuel injection system optimization is required in order to improve atomization and lower the emissions.

2021 ◽  
pp. 146808742110183
Author(s):  
Jonathan Martin ◽  
André Boehman

Compression-ignition (CI) engines can produce higher thermal efficiency (TE) and thus lower carbon dioxide (CO2) emissions than spark-ignition (SI) engines. Unfortunately, the overall fuel economy of CI engine vehicles is limited by their emissions of nitrogen oxides (NOx) and soot, which must be mitigated with costly, resource- and energy-intensive aftertreatment. NOx and soot could also be mitigated by adding premixed gasoline to complement the conventional, non-premixed direct injection (DI) of diesel fuel in CI engines. Several such “dual-fuel” combustion modes have been introduced in recent years, but these modes are usually studied individually at discrete conditions. This paper introduces a mapping system for dual-fuel CI modes that links together several previously studied modes across a continuous two-dimensional diagram. This system includes the conventional diesel combustion (CDC) and conventional dual-fuel (CDF) modes; the well-explored advanced combustion modes of HCCI, RCCI, PCCI, and PPCI; and a previously discovered but relatively unexplored combustion mode that is herein titled “Piston-split Dual-Fuel Combustion” or PDFC. Tests show that dual-fuel CI engines can simultaneously increase TE and lower NOx and/or soot emissions at high loads through the use of Partial HCCI (PHCCI). At low loads, PHCCI is not possible, but either PDFC or RCCI can be used to further improve NOx and/or soot emissions, albeit at slightly lower TE. These results lead to a “partial dual-fuel” multi-mode strategy of PHCCI at high loads and CDC at low loads, linked together by PDFC. Drive cycle simulations show that this strategy, when tuned to balance NOx and soot reductions, can reduce engine-out CO2 emissions by about 1% while reducing NOx and soot by about 20% each with respect to CDC. This increases emissions of unburnt hydrocarbons (UHC), still in a treatable range (2.0 g/kWh) but five times as high as CDC, requiring changes in aftertreatment strategy.


2018 ◽  
Vol 10 (12) ◽  
pp. 168781401881407
Author(s):  
Yasin Karagöz ◽  
Majid Mohammad Sadeghi

In this study, it was aimed to operate today’s compression ignition engines easily in dual-fuel mode with a developed electronic control unit. Especially, diesel engines with mechanical fuel system can be easily converted to common-rail fuel system with a developed electronic control unit. Also, with this developed electronic control unit, old technology compression ignition engines can be turned into dual-fuel mode easily. Thus, thanks to the flexibility of engine maps to be loaded into the electronic control unit, diesel engines can conveniently be operated with alternative gas fuels and diesel dual fuel. In particular, hydrogen, an alternative, environmentally friendly, and clean gas fuel, can easily be used with diesel engines by pilot spraying. Software and hardware development of electronic control unit are made, in order to operate a diesel engine with diesel+hydrogen dual fuel. Finally, developed electronic control unit was reviewed on 1500 r/min stable engine speed on different hydrogen energy rates (0%, 15%, 30%, and 45% hydrogen) according to thermic efficiency and emissions (CO, total unburned hydrocarbons, NOx, and smoke), and apart from NOx emissions, a significant improvement has been obtained. There was no increased NOx emission on 15% hydrogen working condition; however, on 45% hydrogen working condition, a dramatic increase arose.


2015 ◽  
Vol 77 (8) ◽  
Author(s):  
I. M. Yusri ◽  
M. K. Akasyah ◽  
R. Mamat ◽  
O. M. Ali

The use of biomass based renewable fuel, n-butanol blends for compression ignition (CI) engine has attracted wide attention due to its superior properties such as better miscibility, higher energy content, and cetane number as compared to other alternatives fuel. In this present study the use of n-butanol 10% blends (Bu10) with diesel fuel has been tested using multi-cylinder, 4-stroke engine with common rail direct injection system to investigate the combustion and emissions of the blended fuels. Based on the tested engine at BMEP=3.5Bar. Based on the results Bu10 fuel indicates lower first and second peak pressure by 5.4% and 2.4% for engine speed 1000rpm and 4.4% and 2.1% for engine speed 2500rpm compared to diesel fuel respectively. Percentage reduction relative to diesel fuel at engine speeds 1000rpm and 2500rpm for Bu10: Exhaust temperature was 7.5% and 5.2% respectively; Nitrogen oxides (NOx) 73.4% and 11.3% respectively.


Author(s):  
Bibhuti B. Sahoo ◽  
Niranjan Sahoo ◽  
Ujjwal K. Saha

Synthesis gas (Syngas), a mixture of hydrogen and carbon monoxide, can be manufactured from natural gas, coal, petroleum, biomass, and even from organic wastes. It can substitute fossil diesel as an alternative gaseous fuel in compression ignition engines under dual fuel operation route. Experiments were conducted in a single cylinder, constant speed and direct injection diesel engine fuelled with syngas-diesel in dual fuel mode. The engine is designed to develop a power output of 5.2 kW at its rated speed of 1500 rpm under variable loads with inducted syngas fuel having H2 to CO ratio of 1:1 by volume. Diesel fuel as a pilot was injected into the engine in the conventional manner. The diesel engine was run at varying loads of 20, 40, 60, 80 and 100%. The performance of dual fuel engine is assessed by parameters such as thermal efficiency, exhaust gas temperature, diesel replacement rate, gas flow rate, peak cylinder pressure, exhaust O2 and emissions like NOx, CO and HC. Dual fuel operation showed a decrease in brake thermal efficiency from 16.1% to a maximum of 20.92% at 80% load. The maximum diesel substitution by syngas was found 58.77% at minimum exhaust O2 availability condition of 80% engine load. The NOx level was reduced from 144 ppm to 103 ppm for syngas-diesel mode at the best efficiency point. Due to poor combustion efficiency of dual fuel operation, there were increases in CO and HC emissions throughout the range of engine test loads. The decrease in peak pressure causes the exhaust gas temperature to rise at all loads of dual fuel operation. The present investigation provides some useful indications of using syngas fuel in a diesel engine under dual fuel operation.


Author(s):  
Gong Chen

It is always desirable for a heavy-duty compression-ignition engine, such as a diesel engine, to possess a capability of using alternate liquid fuels without significant hardware modification to the engine baseline. Because fuel properties vary between various types of liquid fuels, it is important to understand the impact and effects of the fuel properties on engine operating and output parameters. This paper intends and attempts to achieve that understanding and to predict the qualitative effects by studying analytically and qualitatively how a heavy-duty compression-ignition engine would respond to the variation of fuel properties. The fuel properties considered in this paper mainly include the fuel density, compressibility, heating value, viscosity, cetane number, and distillation temperature range. The qualitative direct and end effects of the fuel properties on engine bulk fuel injection, in-cylinder combustion, and outputs are analyzed and predicted. Understanding these effects can be useful in analyzing and designing a compression-ignition engine for using alternate liquid fuels.


2013 ◽  
Vol 388 ◽  
pp. 217-222
Author(s):  
Mohamed Mustafa Ali ◽  
Sabir Mohamed Salih

Compression Ignition Diesel Engine use Diesel as conventional fuel. This has proven to be the most economical source of prime mover in medium and heavy duty loads for both stationary and mobile applications. Performance enhancements have been implemented to optimize fuel consumption and increase thermal efficiency as well as lowering exhaust emissions on these engines. Recently dual fueling of Diesel engines has been found one of the means to achieve these goals. Different types of fuels are tried to displace some of the diesel fuel consumption. This study is made to identify the most favorable conditions for dual fuel mode of operation using Diesel as main fuel and Gasoline as a combustion improver. A single cylinder naturally aspirated air cooled 0.4 liter direct injection diesel engine is used. Diesel is injected by the normal fuel injection system, while Gasoline is carbureted with air using a simple single jet carburetor mounted at the air intake. The engine has been operated at constant speed of 3000 rpm and the load was varied. Different Gasoline to air mixture strengths investigated, and diesel injection timing is also varied. The optimum setting of the engine has been defined which increased the thermal efficiency, reduced the NOx % and HC%.


2005 ◽  
Vol 121 (2) ◽  
pp. 30-45
Author(s):  
Zdzisław STELMASIAK

Perspectives of usage natural gas in feeding systems of internal combustion engines and development of electronic control systems have resulted in survived interest in dual fuel system of engine feeding. Compression ignition, dual fuel engine enables to preserve majority of positive features of compression ignition engine and shows many advantageous features comparing with gaseous engine with spark ignition system. The paper shows an impact of gaseous mixture composition on operational parameters of the engine, with special consideration of combustion parameters and toxicity of exhaust gases. It has been confirmed that in range of gaseous mixture composition change in scope of λo = 1.4–6.0 worsening of combustion parameters is negligible and can be accepted for medium size traditional engines. Simultaneously, in spite of implementation of traditional injection system, leaning of the mixture up to λo < 6.0 enables significant change of engine load. Limitation of leaning of the mixture up to λo < 4.5, restricts harmful phenomena connected with combustion of lean gaseous mixtures. It requires, however, fuel injection electronic systems such as common rail. Results presented in the paper can be useful in adaptations of compression ignition engine to gaseous feeding and in stage of development of control systems to such engines.


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