Effect of the fuelling strategy on the combustion and emission characteristics of a gasoline–diesel dual-fuel engine

Author(s):  
Joonho Jeon ◽  
Seokhwon Lee ◽  
Sungwook Park

Since improving the energy efficiency and reducing the air pollution are two of the largest issues in the automobile industry, many researchers have developed various combustion and emission technologies to solve these challenges. Among these various technologies, the gasoline–diesel dual-fuel method is of interest to improve the thermal efficiency and to reduce the emissions in diesel engines. The gasoline allows formation of a premixed fuel–air mixture without early ignition owing to its high evaporation rate and low reactivity. In order to investigate the effect of gasoline on the dual-fuel combustion and emission characteristics, combustion of gasoline–diesel blend fuels was simulated in a compression ignition engine by using the KIVA-3V code. For the multi-fuel simulations, a modified KIVA-3V code with a discrete multi-component model was used to represent the multi-fuel evaporation processes. This study showed that the gasoline in the dual-fuel blend improved the fuel–air mixing process to form homogeneous mixtures for the two different injection strategies: port fuel injection and direct injection of gasoline. In addition, the combustion characteristics of gasoline–diesel blend fuel were discussed by comparing them with those of the conventional diesel fuel. The gasoline in the dual-fuel blend increases the indicated power because of the release of high fuel energy and decreases the soot emissions. In this study, various gasoline-to-diesel ratios and various injection timings were used in order to enhance the understanding of the dual-fuel engine. The present study showed that low emissions and a high indicated power were achieved as the gasoline content is increased up to a certain value. However, an increase in the gasoline content in the dual fuel caused the autoignition and the combustion performance to deteriorate.

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.


2012 ◽  
Vol 512-515 ◽  
pp. 1888-1891
Author(s):  
Jia Yi Du ◽  
Wei Xun Zhang ◽  
Deng Pan Zhang ◽  
Zhen Yu Sun

The influence of cetane number improver on emission characteristics of diesel engine fueled with methanol/diesel blend fuel was investigated. Methanol/diesel blend fuel was prepared, in which the methanol content is 10%, different mass fraction (0%,0.5%) of cetane number improver were added to the blend fuel. Load characteristic experiments at maximum torque speed of the engine were carried out on 4B26 direct injection diesel engine. The results show that, compared with the engine fueled with diesel, the CO emission increases under low loads and reduces under medium and high loads, the HC emission increases, the NOx emission decreases under medium and low loads and increases under high loads, the soot emission reduces significantly when the diesel engine fueled with blends. When cetane number improver was added to blends, the CO and NOx emission reduces, the HC emission decreases, the soot emission increases to some extent compared with the methanol/dieselblend fuel without cetane number improver.


Author(s):  
A. Prabu

An experimental investigation was conducted to disclose the outcomes of oxygenate mixture as additives in Jatropha biodiesel on the performance, combustion, and emission characteristics of a direct injection compression ignition engine. The experiments were conducted in an instrumented single-cylinder, air-cooled, four-stroke, direct-injection diesel engine, equipped with data acquisition system, AC alternator, and an electric loading device. Four oxygenate additives, namely, Ethylene Glycol (C2H6O2), Di methyl Carbonate (C3H6O3), 2-Butoxyethanol (C6H14O2), & Propylene Glycol (C3H8O2) were selected and nine different combinational oxygenate test fuels were prepared attaining ratios of 1, 2, and 4% volume of oxygenates with biodiesel. A significant reduction of emissions such as CO by 60%, Unburned HC by 11%, and smoke emissions by 27% were observed. Substantial improvement in brake thermal efficiency by 6% was observed, while NO emission increased marginally by 4%.


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.


2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Akhilendra Pratap Singh ◽  
Avinash Kumar Agarwal

Fuel injection parameters such as fuel injection pressure (FIP) and start of main injection (SoMI) timings significantly affect the performance and emission characteristics of a common rail direct injection (CRDI) diesel engine. In this study, a state-of-the-art single cylinder research engine was used to investigate the effects of fuel injection parameters on combustion, performance, emission characteristics, and particulates and their morphology. The experiments were carried out at three FIPs (400, 700, and 1000 bar) and four SoMI timings (4 deg, 6 deg, 8 deg, and 10 deg bTDC) for biodiesel blends [B20 (20% v/v biodiesel and 80% v/v diesel) and B40 (40% v/v biodiesel and 60% v/v diesel)] compared to baseline mineral diesel. The experiments were performed at a constant engine speed (1500 rpm), without pilot injection and exhaust gas recirculation (EGR). The experimental results showed that FIP and SoMI timings affected the in-cylinder pressure and the heat release rate (HRR), significantly. At higher FIPs, the biodiesel blends resulted in slightly higher rate of pressure rise (RoPR) and combustion noise compared to baseline mineral diesel. All the test fuels showed relatively shorter combustion duration at higher FIPs and advanced SoMI timings. The biodiesel blends showed slightly higher NOx and smoke opacity compared to baseline mineral diesel. Lower particulate number concentration at higher FIPs was observed for all the test fuels. However, biodiesel blends showed emission of relatively higher number of particulates compared to baseline mineral diesel. Significantly lower trace metals in the particulates emitted from biodiesel blend fueled engine was an important finding of this study. The particulate morphology showed relatively smaller number of primary particles in particulate clusters from biodiesel exhaust, which resulted in relatively lower toxicity, rendering biodiesel to be more environmentally benign.


Processes ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. 946 ◽  
Author(s):  
Wojciech Tutak ◽  
Arkadiusz Jamrozik

The aim of the work is a comparison of two combustion systems of fuels with different reactivity. The first is combustion of the fuel mixture and the second is combustion in a dual-fuel engine. Diesel fuel was burned with pure ethanol. Both methods of co-firing fuels have both advantages and disadvantages. Attention was paid to the combustion stability aspect determined by COVIMEP as well as the probability density function of IMEP. It was analyzed also the spread of the maximum pressure value, the angle of the position of maximum pressure. The influence of ethanol on ignition delay time spread and end of combustion process was evaluated. The experimental investigation was conducted on 1-cylinder air cooled compression ignition engine. The test engine operated with constant rpm equal to 1500 rpm and constant angle of start of diesel fuel injection. The engine was operated with ethanol up to 50% of its energy fraction.


2018 ◽  
Vol 7 (4.24) ◽  
pp. 157 ◽  
Author(s):  
P Moulali ◽  
T H Prasad ◽  
B D Prasad

In this paper the emission characteristics and performance of various bio diesel fuels (Tyre pyrolysis oil (TPO), Micro algae oil and Pig animal fat oil) were experimented. A single cylinder, water cooled diesel engine was modified in to homogeneous charge compression ignition engine (HCCI) with adopted port fuel injection (PFI) technique. The effects of air fuel ratio, intake temperature, injection pressure and EGR rate exhaust emissions were explained in a broad manner. The analysis of the exhaust emissions are integrated to oxides of Nitrogen (NOx), Carbon Monoxide (CO), unburned hydro carbons (UHC), smoke and soot. The performance analysis was also included on specific fuel consumption and break thermal efficiency. The basic requirements for HCCI engine is the homogeneous mixture preparation of air and fuel. This mixture formation was done by adopting port fuel injection technique and external devices were also used for bio diesel vaporization and mixture preparation. The combustion processes were measured with different EGR system.  The experimental results of different bio diesel fuels with HCCI engine mode were recorded and evaluated. A small increase in CO and HC emissions were observed with increasing bio diesel content due to slow evaporation rate of bio diesel. A significant reduction in NOx emission was also observed with respect to difference in bio diesel blends. Micro algae oil was found more stable compared with other bio diesel fuels due to the property of fuel vaporization and low heat releasing.


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