The effect of direct water injection on the combustion stability of a downsized boost engine under high compression ratios and load conditions

Liu, Zuowen; Zheng, Zhimin; Zhang, Zhiyong; Li, Ming

doi:10.1016/j.fuel.2021.121945

Cited by 18 publications

(5 citation statements)

References 31 publications

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“…This study applies to the high energy ignition system to obtain 424 mJ of sparking energy. [ 22 ] The testing devices are shown in Table 1 , and more details regarding the engine setup can be found in the literature. [ 22 ]…”

Section: Methodsmentioning

confidence: 99%

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Split Injection Strategy Optimization to Achieve Ideal Stratified‐Charge Mixture and Reinforce Ultralean Burn in a High Compression Ratio Direct Injection Spark Ignition Engine

Liu

Zheng

2022

Energy Tech

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Ultralean burn is considered an effective way to enhance the thermal efficiency of direct injection spark ignition engines. Herein, under ultralean burn condition, the split injection strategy is induced to investigate the in‐cylinder mixture distribution, combustion characteristics, and emissions by simulation in a high compression ratio engine model. First, the homogeneity index shows that compared with the single injection method, the split injection strategy shows better stratification of the mixture gas at the early stage of the compression stroke, which results in higher in‐cylinder pressure and heat release. Meanwhile, the results of heat balance show that split injection shows a slight effect on ignition delay, but significantly shortens combustion duration and advances CA50, and thus the exhaust loss is decreased. Second, with the decrease of a second injection fuel mass, the rich mixture is formed near the spark plug, thus reducing the ignition delay and combustion duration. Third, the split injection strategy presents faster flame kernel growth and propagation. A larger flame area is observed with the second injection mass decreasing. Finally, as the second fuel injection mass is reduced, NOx emissions increases continuously, while the soot emission decreases.

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Section: Methodsmentioning

confidence: 99%

“…[ 22 ] The testing devices are shown in Table 1 , and more details regarding the engine setup can be found in the literature. [ 22 ]…”

Section: Methodsmentioning

confidence: 99%

Split Injection Strategy Optimization to Achieve Ideal Stratified‐Charge Mixture and Reinforce Ultralean Burn in a High Compression Ratio Direct Injection Spark Ignition Engine

Liu

Zheng

2022

Energy Tech

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“…Water injection also caused a decrease in NO x emissions, as well as soot emissions. Pei et al 11 and Liu et al 12 measured the effects of water injection on the knocking and combustion processes of a GDI engine with a high compression ratio (CR). Pei et al found that when the water injection ratio is increased to 50%, engine knock drops by 82.7% and the indicated specific fuel consumption drops by 9.9%.…”

Section: Introductionmentioning

confidence: 99%

“…Too much water injection may cause the water in the cylinder to atomize too late, making fuel mixing insufficient. Therefore, many scholars have investigated this topic. − Kim et al studied the effect of DWI on gasoline engines through experiments and found that increasing the injected water mass resulted in further spark advance without knock occurrence and provided room for further brake-specific fuel consumption reduction. Wei et al used the computational fluid dynamics (CFD) method to inject different proportions of water into a GDI engine to explore its impact on engine performance and emissions.…”

Section: Introductionmentioning

confidence: 99%

Research on the Effect of Water Injection Pressure on Knocking Combustion of a Direct Injection Gasoline Engine

Dai

Zheng

2022

ACS Omega

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In this study, the research method of numerical simulation is used to explore the inhibition of different water injection pressures on knock combustion of turbocharged direct injection gasoline (GDI) engines by coupling computational fluid dynamics with a chemical-kinetics model. First, the ignition advance angle and compression ratio are increased to induce the GDI engine to knock, and then the influence of the water injection pressure on the in-cylinder, evaporation of water, and the knock of the gasoline engine are analyzed. The simulation results show that, compared with no water injection, the direct injection of water in the cylinder can significantly reduce the knock intensity. When the water injection pressure is greater than 40 bar, the knock intensity is less than 2 and the knocking is completely suppressed. In this work, the effects of different water injection pressures on knocking are explored by analyzing the effects of water injection pressure on water atomization, in-cylinder combustion, and the knocking mechanism. On the one hand, the evaporation rate of water increases with increasing water injection pressure and the quality of the liquid film generally improves. On the other hand, direct water injection can significantly reduce the distribution of CH 2 O in the end mixture, thereby reducing the generation of H 2 O 2 and further suppressing the spontaneous combustion of the end mixture. At the moment of knock, when the water injection pressure is greater than 40 bar, the detonation mechanism of the no. 7 monitoring point does not produce a sudden change in HCO radicals. The water spray can effectively reduce the NO x emission, and the NO x emission under the water spray pressure of 120 bar is the lowest. However, after spraying water, it will increase CO emissions.

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“…The study of the combustion stability of engines equipped with direct water injection systems, especially under conditions of compression ratios and high loads, is important to achieve the stable operation of small caliber but high thermal efficiency engines. Thus, Suowen Liu et al [19], implement water injection in a small engine to ensure the stability of combustion. The results show that as the water mass increases, the increase in combustion time and the delay of the combustion phase at a fixed ignition moment create fluctuations in cycle-to-cycle variations of the indicated average effective pressure.…”

Section: Introductionmentioning

confidence: 99%

Effect of direct water injection on emission of pollutants in a diesel engine using CFD and water/fuel mass ratio based parametric analysis

NKOL

Banta

Offole

et al. 2022

Preprint

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One of the current major challenges in the industry is to considerably reduce polluting emissions from internal combustion engines to comply with increasingly strict anti-pollution standards and to remain competitive in the face of the rapid spread of green technologies. The work carried out in this paper focused on a study of the effect of direct water injection on the emission of pollutants in a diesel engine. The strategy of injecting water into the combustion chamber allows better control of the combustion phase and improves engine performance due to the temperature drop during combustion. This work aims to develop a CFD model of a diesel engine with direct water injection in the combustion chamber and to analyze the effects of water/fuel ratio on combustion, particularly on pollutant emissions. The novelty of this work is the realization of a parametric CFD study based on the water/fuel mass ratio, which is a powerful indicator that can effectively generalize the results obtained to engines of different architecture and consumption. For it, data were taken from the work done at Sandia National Laboratories by Stephen Bush and his team from a light unicycle optical diesel engine. These data made possible to design and validate a CFD model. After that we associate a model of direct injection of water, which has also been validated. Finally, we analyze the effects of water/fuel mass ratio on combustion and particularly on pollutant emissions. This work shows that the injection of water into the combustion chamber of the engine effectively reduces the emission levels of pollutants in nature. Thus, depending on the value of the water/fuel ratio, there is a reduction of 2% − 30% of NOx, 5% − 70% of soot, 5% − 40% for CO and 3% − 30% for HC.

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The effect of direct water injection on the combustion stability of a downsized boost engine under high compression ratios and load conditions

Cited by 18 publications

References 31 publications

Split Injection Strategy Optimization to Achieve Ideal Stratified‐Charge Mixture and Reinforce Ultralean Burn in a High Compression Ratio Direct Injection Spark Ignition Engine

Split Injection Strategy Optimization to Achieve Ideal Stratified‐Charge Mixture and Reinforce Ultralean Burn in a High Compression Ratio Direct Injection Spark Ignition Engine

Research on the Effect of Water Injection Pressure on Knocking Combustion of a Direct Injection Gasoline Engine

Effect of direct water injection on emission of pollutants in a diesel engine using CFD and water/fuel mass ratio based parametric analysis

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