A Simulation Study of Water Injection Position and Pressure on the Knock, Combustion, and Emissions of a Direct Injection Gasoline Engine

Li, Aqian; Zheng, Zhimin; Song, Yukun

doi:10.1021/acsomega.1c01792

Cited by 7 publications

(13 citation statements)

References 44 publications

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“…The initial conditions and boundary conditions were calculated from experiments and 1D GT-Power software. 18 The initial conditions are shown in Table 4, and refer to the pressure, temperature, and other components. The boundary conditions mainly conclude: the piston top temperature is 565.9 K, the wall temperature of the combustion chamber is 565 K, the temperature of the spark plug is 1100 K, and the temperature parameters of other parts.…”

Section: Initial and Boundary Conditionsmentioning

confidence: 99%

“…The experimental conditions were from previous studies. 18 Figure 4 shows a comparison of experimental and numerical results on mean pressure and heat release rate (HRR). It can be seen from the figure that the simulation results of the mean pressure and HRR are well coupled with the experimental results, and the deviations are not more than 5%.…”

Section: Grid Independence and Numerical Model Verificationmentioning

confidence: 99%

“…Other strategies for suppressing engine knock with PWI have also been extensively studied by many scholars. [16][17][18][19][20][21][22][23][24][25] Water injection strategies must include timing, pressure, and quality. Souza Alvarenga Santos et al 16 researched the water injection control parameters in a single-cylinder engine with an experimental study and CFD method.…”

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confidence: 99%

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Effect of port water injection on suppressing knock in gasoline direct injection engines

Dai

zheng

Song

2022

Energy Science & Engineering

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The effect of different port water injection (PWI) ratios on the knock in gasoline direct injection engines is explored. First, a simulation study is carried out under knock conditions to explore the time and location of the knock and the chemical mechanism that causes it. Second, water injection amount to 10%, 20%, 30%, and 40% are set to explore the effects of different water injection ratios on knocking. The influence of the different water injection ratios on the chemical mechanism of knocking is evaluated and that of the chemical mechanism on the in‐cylinder temperature and the impact of heat release rate (HRR) is explored. The results show that PWI can effectively reduce the occurrence of spontaneous combustion in the cylinder by reducing the flame propagation speed. On one hand, the changes in the low‐temperature reaction substances CH2O and HRR tend to be consistent and the peaks of CH2O and HRR move back with the increase in water injection. So, different ratios of PWI can affect the flame propagation speed by affecting the generation and consumption of CH2O, OH radicals, and HCO radicals. Also, PWI can significantly reduce the generation of in‐cylinder OH radicals, ultimately suppressing the generation of the high‐temperature stage. In addition, PWI can effectively reduce the mean temperature and mean pressure. Compared to other water injection ratios, a 30% water injection ratio is the most effective at inhibiting knocking. At this time, the knocking intensity is the lowest, and the cycle power reaches its maximum of 1120 J.

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Section: Initial and Boundary Conditionsmentioning

confidence: 99%

Section: Grid Independence and Numerical Model Verificationmentioning

confidence: 99%

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confidence: 99%

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Effect of port water injection on suppressing knock in gasoline direct injection engines

Dai

zheng

Song

2022

Energy Science & Engineering

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“…In terms of the pressure of PWI, Rocha et al 26 determined through experiments that water injection time and water injection pressure have a greater impact on fuel consumption when the IMEP is 8 bar than when the IMEP is 5 bar. Meanwhile, Li et al 27 found that the KI of the GDI engine was the lowest when the water injection pressure was set at 5 bar. During this time, the work cycle volume is the highest and the emissions of NO x and HC are the lowest.…”

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 studies carried out focus on the injection of water in the intake manifold or creating an emulsion of water with the fuel injected, which shows the significant impact that the increase of water content has on the combustion efficiency and thus on the performance of the engine. This has been demonstrated with different kinds of thermal engines, such as gas turbines [64], diesel internal combustion engines [65]- [71], and petrol engines [66], [72]- [74]; obtaining the same result trend about the effect of the combustion air humidity on the performance and pollutant emissions of a thermal engine.…”

Section: Humiditymentioning

confidence: 84%

Development of an Installation to Emulate Altitude, Ambient Temperature, and Ambient Humidity on Thermal Engines. Application to the Study of the Impact over E6 Engine Performance

Aleixandre¹

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A Simulation Study of Water Injection Position and Pressure on the Knock, Combustion, and Emissions of a Direct Injection Gasoline Engine

Cited by 7 publications

References 44 publications

Effect of port water injection on suppressing knock in gasoline direct injection engines

Effect of port water injection on suppressing knock in gasoline direct injection engines

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

Development of an Installation to Emulate Altitude, Ambient Temperature, and Ambient Humidity on Thermal Engines. Application to the Study of the Impact over E6 Engine Performance

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