Effects of pre-injection strategy on combustion performance of methanol/diesel dual fuel engine at low load

In this paper, the effect of pre-injection timing on the combustion and emission performance of methanol/diesel high premixed charge compression ignition (HPCCI) combustion mode at low load was studied by three-dimensional numerical simulation. The simulation is carried out under the conditions of 1900 r/min and 25% load, and the pre-injection diesel mass remains constant and the pre-injection timing is changed under the conditions of 50% and 60% methanol ratio respectively. The results show that with the delay of pre-injection timing, the evaporation of pre-injected fuel in cylinder becomes faster, the low temperature reaction is enhanced, and the peak value of heat release rate is higher. In addition, the distribution of pre-injected diesel in cylinder and the position of impact wall are the important factors affecting the combustion and emission performance in cylinder, and when the injection timing is -35 °CA ATDC, the combustion and emission characteristics of the engine are optimal. Finally, by comparing with the traditional RCCI combustion mode, the enhancement ability of HPCCI combustion mode on methanol combustion efficiency under low load is verified and analyzed.

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Factors Affecting Performance of Dual Fuel Compression Ignition Engines

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.388.217 ◽

2013 ◽

Vol 388 ◽

pp. 217-222

Author(s):

Mohamed Mustafa Ali ◽

Sabir Mohamed Salih

Keyword(s):

Diesel Engine ◽

Fuel Consumption ◽

Thermal Efficiency ◽

Fuel Injection ◽

Direct Injection ◽

Injection System ◽

Dual Fuel ◽

Injection Timing ◽

Compression Ignition ◽

Factors Affecting

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%.

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Impact of injection settings on gaseous emissions and particle size distribution in the dual-mode dual-fuel concept

International Journal of Engine Research ◽

10.1177/1468087419844413 ◽

2019 ◽

Vol 21 (4) ◽

pp. 561-577 ◽

Cited By ~ 3

Author(s):

Vicente Bermúdez ◽

Vicente Macián ◽

David Villalta ◽

Lian Soto

Keyword(s):

Nitrogen Oxide ◽

Injection Pressure ◽

Dual Fuel ◽

Injection Timing ◽

Compression Ignition ◽

Dual Mode ◽

Reactivity Controlled Compression Ignition ◽

Accumulation Mode ◽

Low Load ◽

Main Injection

Reactivity controlled compression ignition concept has been highlighted among the low temperature combustion strategies. However, this combustion strategy presents some problems related to high levels of hydrocarbon and carbon monoxide emissions at low load and high-pressure rise rate at high load. Therefore, to diminish these limitations, the dual-mode dual-fuel concept has been presented as an excellent alternative. This concept uses two fuels of different reactivity and switches from a dual-fuel fully premixed strategy (based on the reactivity controlled compression ignition concept) during low load to a diffusive nature during high load operation. However, the success of dual-mode dual-fuel concept depends to a large extent on the low reactivity/high reactivity fuel ratio and the injection settings. In this study, parametric variations of injection pressure and injection timing were experimentally performed to analyze the effect over each combustion process that encompasses the dual-mode dual-fuel concept and its consequent impact on gaseous and particles emissions, including an analysis of particle size distribution. The experimental results confirm how the use of an adequate injection strategy is indispensable to obtain low exhaust emission and a balance between the different pollutants. In the fully premixed reactivity controlled compression ignition strategy, the particles concentrations were dominated by nucleation mode; however, the increase in injection pressure and the advance of the diesel main injection timing provided a simultaneous reduction of nitrogen oxide and solid particles (accumulation mode). During the highly premixed reactivity controlled compression ignition strategy, the accumulation-mode particles increased, and their concentrations were higher when the diesel main injection timing advanced and injection pressure decreased, as well as there was a slight increase in nitrogen oxide emissions. Finally, in the dual-fuel diffusion strategy, the concentrations of accumulation-mode particles were higher and there was a considerable increase of these particles with the advance of the diesel main injection timing and the reduction of the injection pressure, while the nitrogen oxide emissions decreased.

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Combustion and Emission Characteristics of a CI Engine Operating in Diesel-1-Butanol/CNG Dual Fuel Mode With Low and High CNG Substitution Rates in Light Load Operation

ASME 2016 Internal Combustion Engine Fall Technical Conference ◽

10.1115/icef2016-9456 ◽

2016 ◽

Author(s):

Xiangyu Meng ◽

Yuanxu Li ◽

Karthik Nithyanandan ◽

Wuqiang Long ◽

Chia-Fon F. Lee

Keyword(s):

Thermal Efficiency ◽

Substitution Rate ◽

Fuel Combustion ◽

Dual Fuel ◽

Injection Timing ◽

Combustion Mode ◽

Substitution Rates ◽

Low Load ◽

Pilot Fuel ◽

Dual Fuel Combustion

Dual-fuel combustion mode with direct injection of diesel as the pilot fuel and port injection of compressed natural gas (CNG) in compression ignition (CI) engines has been widely investigated to comply with the latest emission regulations. The diesel-CNG dual-fuel combustion mode shows some potential to decrease NOx and soot emissions simultaneously, while it reveals a lower thermal efficiency compared to the pure diesel combustion mode under low load condition. The purpose of the current study is to investigate the possibility of using diesel blended with 1-butanol as the pilot fuel to enhance the engine performance and reduce emissions. Three pilot fuels — B0 (pure diesel), B10 (90% diesel and 10% 1-butanol by volume) and B20 (80% diesel and 20% 1-butanol) with the CNG substitution rates of 50% and 80% were compared at an engine speed of 1200 rpm. The experiments were conducted by sweeping the pilot fuel injection timing from −3 to −18 ° CA ATDC with an equivalent total energy (∼5 bar IMEP). The results illustrated that, for the 50% CNG substitution rate, the dual-fuel operation mode revealed a higher indicated thermal efficiency (ITE) under low load conditions, and B10 can significantly improve the ITE due to the shorter combustion duration. The emission results of B10 showed that it obtained lower THC and CO emissions, but a slightly higher NOx emission. For the 80% CNG substitution rate, the results presented lower ITE, higher THC and lower NOx emissions, comparatively.

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Performance, combustion, and emission evaluation of ethanol-gasoline blends ignited by diesel in dual-fuel intelligent charge compression ignition (ICCI) engine

Journal of Energy Resources Technology ◽

10.1115/1.4052910 ◽

2021 ◽

pp. 1-21

Author(s):

Yaoyuan Zhang ◽

Wenbin Zhao ◽

Haoqing Wu ◽

Zhuoyao He ◽

Yong Qian ◽

...

Keyword(s):

High Efficiency ◽

Carbon Chain ◽

Dual Fuel ◽

Carbon Chain Length ◽

Injection Timing ◽

Compression Ignition ◽

Combustion Mode ◽

Pure Ethanol ◽

Wide Range ◽

Homogeneous Combustion

Abstract A recent proposed dual-fuel combustion mode, intelligent charge compression ignition (ICCI), realizes the high-efficiency and clean combustion by organizing continuous stratification in a wide range of engine load. The paper investigated the performance of alcohol blended gasoline as low reactivity fuel (LRF) in ICCI combustion mode. Pure ethanol named E100 was also tested as LRF for comparison. To emphasize the differences of LRF properties and exclude the effect of the heat release phasing, the diesel injection timing was adjusted to maintain the same combustion phasing (CA50) at various LRF ratios under medium load. The results showed that E100 and E85 (ethanol ratio in gasoline-ethanol blend) promoted the degree of homogeneous combustion and eradicated soot emissions despite a slight increase of NOx. The maximum indicated thermal efficiency (ITE) was over 51.1% using E85, followed by 50.5% of E50. The perfect substitution ratio at the maximum ITE decreased from more than 80% to about 65% when increasing the ethanol ratio in LRF from 10% to 100%. The unregulated emissions such as aldehydes, ethylene, and methane, produced from incomplete combustion of ethanol were inhabited by E85, while the formation of toluene attributed to the appropriate carbon chain length of gasoline diminished when using E85 and E100.

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DoE Method for Operating Parameter Optimization of a Dual-Fuel BioEthanol/Diesel Light Duty Engine

Journal of Fuels ◽

10.1155/2015/674705 ◽

2015 ◽

Vol 2015 ◽

pp. 1-14 ◽

Cited By ~ 7

Author(s):

Gabriele Di Blasio ◽

Mauro Viscardi ◽

Carlo Beatrice

Keyword(s):

Statistical Design ◽

Operating Parameter ◽

Combustion Efficiency ◽

Dual Fuel ◽

Compression Ignition ◽

Rail Pressure ◽

Compression Ignition Engines ◽

Injection Parameters ◽

Light Duty ◽

Low Load

In recent years, alcoholic fuels have been considered as an alternative transportation biofuel even in compression ignition engines either as blended in diesel or as premixed fuel in the case of dual-fuel configuration. Within this framework, the authors investigated the possibility to improve the combustion efficiency when ethanol is used in a dual-fuel light duty diesel engine. In particular, the study was focused on reducing the HC and CO emissions at low load conditions, acting on the most influential engine calibration parameters. Since this kind of investigation would require a significant number of runs, the statistical design of experiment methodology was adopted to reduce significantly its number. As required by the DoE approach, a set of factors (injection parameters, etc.) were selected. For each of them, two levels “high” and “low” were defined in a range of reasonable values. Combining the levels of all the factors, it was possible to evaluate the effects and the weight of each factor and of their combination on the outputs. The results identified the rail pressure, the pilot, and post-injection as the most influential emission parameters. Significant reductions of unburnt were found acting on those parameters without substantial penalties on the global engine performances.

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An experimental study of the injection strategies on engine performance of the butanol/biodiesel dual-fuel Intelligent Charge Compression Ignition mode

International Journal of Engine Research ◽

10.1177/1468087420963994 ◽

2020 ◽

pp. 146808742096399

Author(s):

Wenbin Zhao ◽

Yaoyuan Zhang ◽

Guan Huang ◽

Zilong Li ◽

Yong Qian ◽

...

Keyword(s):

Heat Release ◽

Thermal Efficiency ◽

Direct Injection ◽

Dual Fuel ◽

Injection Timing ◽

Nox Emissions ◽

Compression Ignition ◽

Combustion Mode ◽

Low Levels ◽

Injection Strategies

Intelligent Charge Compression Ignition (ICCI) combustion mode is a novel dual-fuel combustion strategy that has been proposed recently. In ICCI combustion mode, two fuels with different reactivity are directly injected during the intake stroke and compression stroke, respectively, to achieve flexible reactivity gradient and equivalence ratio stratification. In this study, experiments were conducted on a single-cylinder diesel engine to investigate the effects of butanol direct injection strategies on the engine running with ICCI combustion mode at a constant speed of 1500 r/min and medium load. Results showed that ICCI combustion mode was composed of premixed heat release and diffusion heat release. In compare, the percentage of premixed heat release was higher than the diffusion heat release. With fixed biodiesel direct injection timing (SOI2), retarding butanol single injection timing (SOI1) would delay combustion phasing while not distinctively affect ignition timing. SOI1 showed significant effect on the thermal efficiency and engine emissions. Indicated thermal efficiency (ITE) decreased at first and then slightly increased with retarding of SOI1, while the nitrogen oxides (NOx) emissions were always at low levels. As the butanol second direct injection timing (SOI1-2) retard and the corresponding energy ratio increase, more butanol entered into the crevice/squish regions, leading to the increase of unburned hydrocarbon (HC) and carbon monoxide (CO) emissions. EGR strategy helps to significantly reduce NOx emissions without affecting ITE although penalized HC and CO emissions are resulted in. The optimum butanol direct injection strategies were butanol single direct injection, especially in the early SOI1, in which the thermal efficiency was higher and emissions were at very low levels (NOx < 0.4 g/kW h).

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