Investigation of Water Injection Effects on Combustion Characteristics of a GDI TC Engine

Cavina, Nicolò; Rojo, Nahuel; Businaro, Andrea; Brusa, Alessandro; Corti, Enrico; Cesare, Matteo De

doi:10.4271/2017-24-0052

Cited by 39 publications

(20 citation statements)

References 8 publications

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“…Observing Figure 13c and considering that the MAPO knee is located at about -22 CAD aTDCf for the baseline no-water case, we conclude from the MAPO curves that about 2 CAD of spark advance are gained, in this engine point, using the low-pressure water injection (with SOI = 0 CAD aTDCf which is the most effective case), and about 6 CAD of spark advance are gained using the high-pressure water injection. The values found here are in very good agreement with engine measurements already reported in [9], for the same engine point. The benefits of a KLSA shift are shown in Figure 13d-e, comparing in-cylinder pressure and HRR curves.…”

Section: Results Under Similar Klsasupporting

confidence: 92%

“…The set of parameters is shown in Table 2, and the resulting engine load is about 14 bar indicated mean effective pressure (IMEP). Water is injected upstream of each runner, controlling the water start of injection, pressure and duration [9]. In this paper, the analysis focuses on a fixed water-to-fuel mass ratio of 30%.…”

Section: Methodsmentioning

confidence: 99%

“…Spray models also include appropriate sub-models for droplet turbulence dispersion, collision, evaporation, and wall film formation, setup according to our previous experience and the general accepted literature [7]. Inlet and outlet pressure boundary conditions and wall temperature conditions are extracted from a validated 1D engine cycle model and measurements collected on the engine dyno [9].…”

Section: Computational Setupmentioning

confidence: 99%

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CFD Analysis of Port Water Injection in a GDI Engine under Incipient Knock Conditions

et al. 2019

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This paper investigates, through computational fluid dynamics (CFD) simulations, the knock resistance improvements that can be obtained in a turbo-charged GDI engine with water injection. In a first step, water and gasoline injector models are validated comparing the results with experimental data from constant volume chamber tests. Then, multi-cycle simulations are performed using the G-equation turbulent combustion model focusing on spray evolution and wall film dynamics. The main intent is analyzing the effectiveness of different water injection timings and injection pressures in a port water injection (PWI) installation. Combustion rates are validated against experimental engine data, with and without water injection. Afterwards, in order to predict autoignition behavior with different spark advance (SA) timings, the extended coherent flamelet model (ECFM) combined with a tabulated kinetic ignition (TKI) dataset is used. End-gas autoignition delays are calculated using a reduced mechanism for toluene primary reference fuel (TPRF), which revealed essential for capturing actual gasoline ignition characteristics. Results indicate that the water atomization quality, i.e., injection pressure, is significant in a PWI installation allowing a reduction of the water wall film formation in the ports. Water injection timing needs also to be carefully chosen for optimized performance. As the injected water allows the SA to be increased, the overall benefits on indicated mean effective pressure and fuel consumption are quantified under the same knock safety margin, matching adequately well the available measurements.

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Section: Results Under Similar Klsasupporting

confidence: 92%

Section: Methodsmentioning

confidence: 99%

Section: Computational Setupmentioning

confidence: 99%

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CFD Analysis of Port Water Injection in a GDI Engine under Incipient Knock Conditions

et al. 2019

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“…In this frame, water injection technology can be used as an alternative way to control the charge temperature at the end of the intake process and during the combustion phase, thus reducing the risk of abnormal combustion in downsized and highly boosted GDI engines. Water injection can potentially enable λ = 1 operation in high-load and highspeed operation, even adopting high compression ratios [7][8][9][10][11][12][13][14][15][16][17], thereby gaining significant benefits in terms of engine efficiency while preserving the after-treatment system efficacy in controlling exhaust emissions.…”

Section: Introductionmentioning

confidence: 99%

“…In this analysis, CFD simulations of the water spray evolution in the intake duct were carried out to investigate the spray-air interaction, but the effect of the spray characteristics with different operating conditions was not investigated. In other numerical analyses of water injection systems, the water spray characteristics, or even its evaporation rate, are assumed to be constant or similar to fuel sprays generated at the same injection pressure level [13,15,16].…”

Section: Introductionmentioning

confidence: 99%

Experimental Analysis of Water Pressure and Temperature Influence on Atomization and Evolution of a Port Water Injection Spray

Postrioti

Brizi²,

Finori

2021

Applied Sciences

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Port water injection (PWI) is considered one of the most promising technologies to actively control the increased knock tendency of modern gasoline direct injection (GDI) engines, which are rapidly evolving with the adoption of high compression ratios and increased brake mean effective pressure levels in the effort to improve their thermal efficiency. For PWI technology, appropriately matching the spray evolution and the intake system design along with obtaining a high spray atomization quality, are crucial tasks for promoting water evaporation so as to effectively cool down the air charge with moderate water consumption and lubricant dilution drawbacks. In the present paper, a detailed experimental analysis of a low-pressure water spray is presented, covering a lack of experimental data on automotive PWI systems. Phase doppler anemometry and fast-shutter spray imaging allowed us to investigate the influence exerted by the injection pressure level and by the water temperature on spray drop size and global shape, obtaining a complete database to be used for the optimization of PWI systems. The obtained results evidence how significant benefits in terms of atomization quality can be obtained by adopting injection pressure and water temperature levels compliant with standard low injection pressure technologies.

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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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Investigation of Water Injection Effects on Combustion Characteristics of a GDI TC Engine

Cited by 39 publications

References 8 publications

CFD Analysis of Port Water Injection in a GDI Engine under Incipient Knock Conditions

CFD Analysis of Port Water Injection in a GDI Engine under Incipient Knock Conditions

Experimental Analysis of Water Pressure and Temperature Influence on Atomization and Evolution of a Port Water Injection Spray

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

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