Evaluation of the Potential of Water Injection for Gasoline Engines

Hoppe, Fabian; Thewes, Matthias; Seibel, Joerg; Balazs, Andreas; Scharf, Johannes

doi:10.4271/2017-24-0149

Cited by 64 publications

(33 citation statements)

References 10 publications

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“…The need for exhaust gas recirculation (EGR) [1] or ultra-lean combustion [2] requires the development of advanced and innovative ignition systems and strategies, by enhancing the thermal energy conversion efficiency, that increases quite linearly with λ [3], and allowing operating conditions characterised by poor pollutant emissions [4,5]. The water injection is also an advanced technology able to improve the combustion in the modern engines for the general performance enhancement [6,7] as well as the thermal efficiency improvement [8,9] or the knocking control strategies [10]. All these new working conditions demand high ignition energy not available for the conventional inductive Pressure gradient due to a streamer event η Thermal efficiency of the igniter ν i…”

Section: Introductionmentioning

confidence: 99%

Experimental characterisation of the thermal energy released by a Radio-Frequency Corona Igniter in nitrogen and air

et al. 2020

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The Radio-Frequency Corona Ignition System is characterised by a wide initial combustion volume and precursors production, via radical insemination by the streamers, in addition to high released thermal energy. These features lead to faster combustion, a higher tolerance for lean mixtures and EGR dilutions and, in general, more adaptability. The thermal energy released by the igniter to the surrounding medium can help to understand the performance, the behaviour and the application range. This paper proposes a systematic experimental analysis of the thermal energy released by the igniter at room temperature, via pressure-based calorimetry. This analysis, carried out at different pressures (up to 10 bar) and medium type (air or nitrogen), is extended to the whole range of the corona igniter control parameters, namely streamer duration and driving voltage. The latter is proportional to the maximum electrode voltage, as shown in the model here presented, and as confirmed by experiments. The results show, for all the vessel pressures, the high energetic efficiency of the ignition system and the high amount of the released energy. The latter is found to increase linearly with the corona streamers duration and quickly with the driving voltage up to the streamer-to-arc transition threshold. The efficiency tends to reach a defined upper limit. For each tested point, the energy released to pure nitrogen is higher than to air, which evidences the impact of the oxygen presence under streamer exposure.

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Section: Introductionmentioning

confidence: 99%

Experimental characterisation of the thermal energy released by a Radio-Frequency Corona Igniter in nitrogen and air

et al. 2020

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“…Fuel enrichment to reduce the thermal stresses of hot engine components can be avoided, providing fuel savings of up to 15-20% at high loads. The reduction of combustion temperatures is also an effective method for NOx control that could replace EGR usage in some strategies [1][2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

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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“…In addition, water is expected to have significantly different physical properties from gasoline, resulting in different injection and spray characteristics. Accordingly, it is essential to understand not only spray characteristics of fuel, but also spray characteristics of water [25]. However, most of water injection research studies focused on the combustion process and exhaust gas research, while research on injection and spray characteristics of the water applied to the PFI system was insufficient.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive Spray Characteristics of Water in Port Fuel Injection Injector

2020

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The objective of this study was to compare the injection and spray characteristics of water with n-heptane using a port fuel injection (PFI) system. In this study, the injection pressure was changed to 0.3–0.9 Mpa and the energizing duration was changed to 0.5–4 ms. To investigate spray characteristics, the injection quantities of n-heptane and water were measured. Macroscopic spray characteristics were determined through spray visualization. The Sauter mean diameter (SMD) and velocity of spray droplets were measured with a phase Doppler anemometry (PDA) experiment. Spray tip penetration, spray angle, SMD of droplets, and spray droplet velocity were compared. As the injection pressure increased, the injection quantity and the droplets velocity increased. However, the spray tip penetration, SMD of the droplet, and the spray angle decreased. The increase in energizing duration led to an increase in the injection quantity without affecting other spray characteristics. The higher density of water also increased injection quantity, resulting in a decrease in spray tip penetration and increases of SMD and velocity of spray droplets due to high viscosity and surface tension of water.

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Evaluation of the Potential of Water Injection for Gasoline Engines

Cited by 64 publications

References 10 publications

Experimental characterisation of the thermal energy released by a Radio-Frequency Corona Igniter in nitrogen and air

Experimental characterisation of the thermal energy released by a Radio-Frequency Corona Igniter in nitrogen and air

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

Comprehensive Spray Characteristics of Water in Port Fuel Injection Injector

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