Split injection in a homogeneous stratified gasoline direct injection engine for high combustion efficiency and low pollutants emission

Costa, Michela; Sorge, Ugo; Merola, Simona Silvia; Irimescu, Adrian; Villetta, M. La; Rocco, Vittorio

doi:10.1016/j.energy.2016.03.065

Cited by 49 publications

(10 citation statements)

References 21 publications

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“…Also, a higher OH formation is found in the 2SIS 1 and 3SIS 2 injection conditions, so a rapid chemical activity occurs. At the advanced combustion phase, the OH emissions reduce because these attend in the postoxidation of the other species by presenting in the combustion chamber . The formation of the OH emission depends on the formation of the in‐cylinder temperature and the air‐fuel mixture.…”

Section: Resultsmentioning

confidence: 99%

Investigation of multistage injection strategies in a DISI engine fueled with methane under stratified charge lean combustion conditions

Fırat

2020

Env Prog and Sustain Energy

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A three‐dimensional numerical study has been performed to study combustion and emission of methane in a stratified charge direct injection spark ignition engines under the multistage injection strategies. Firstly, the combustion and emission characteristics of a single‐injection strategy were investigated, and then the effects of two‐stage and three‐stage injection strategies of the injected fuel on combustion and emissions were analyzed. This simulation was run from intake valve opening to exhaust valve opening under stratified charge conditions using the ANSYS Forte numerical software. The Discrete Particle Ignition Kernel Flame model was used to investigate the ignition process and also the combustion and flame propagation were simulated with the G‐equation model. The numerical results show that the multistage injection strategies achieve a significant improvement in the cylinder pressure and combustion efficiency, while reducing NOx, CO, and unburned hydrocarbon emissions compared to single‐injection strategy under stratified charge conditions. Also, the efficient multistage injection strategies enhanced the benefits of the emission reduction in the stratified lean combustion with additional increases of combustion efficient.

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Section: Resultsmentioning

confidence: 99%

Investigation of multistage injection strategies in a DISI engine fueled with methane under stratified charge lean combustion conditions

Fırat

2020

Env Prog and Sustain Energy

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“…Several researchers studied stratified injection mode [10][11][12][13][14][15] with significant improvements in performance. However, several problems were found in the form of a reduction in combustion stability, difficulties setting the desired air-fuel ratio at spark timing and an increase of particle emissions [13]. Therefore, a potential alternative is the mix of both concepts to achieve a stable combustion process, with low particle emission and without losing performance.…”

Section: Introductionmentioning

confidence: 99%

Flame Front and Burned Gas Characteristics for Different Split Injection Ratios and Phasing in an Optical GDI Engine

2019

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Direct-injection in spark-ignition engines has long been recognized as a valid option for improving fuel economy, reducing CO2 emissions and avoiding knock occurrence due to higher flexibility in control strategies. However, problems associated with mixture formation are responsible for soot emissions, one of the most limiting factors of this technology. Therefore, the combustion process and soot formation were investigated with different injection strategies on a gasoline direct injection (GDI) engine. The experimental analysis was realized on an optically accessible single cylinder engine when applying single, double and triple injection strategies. Moreover, the effect of fuel delivery phasing was also scrutinized by changing the start of the injection during late intake- and early compression-strokes. The duration of injection was split in different percentages between two or three pulses, so as to obtain close to stoichiometric operation in all conditions. The engine was operated at fixed rotational speed and spark timing, with wide-open throttle. Optical diagnostics based on cycle resolved digital imaging was applied during the early and late stages of the combustion process. Detailed information on the flame front morphology and soot formation were obtained. The optical data were correlated to in-cylinder pressure traces and exhaust gas emission measurements. The results suggest that the split injection of the fuel has advantages in terms of reduction of soot formation and NOx emissions and a similar combustion performance with respect to the single injection timing. Moreover, an early injection resulted in higher rates of heat release and in-cylinder pressure, together with a reduction of soot formation and flame distortion. The double injection strategy with higher percentage of fuel injected in the first pulse and early second injection pulse showed the best results in terms of combustion evolution and pollutant emissions. For the operative condition studied, a higher time for mixture homogenization and split of fuel injected in the intake stroke shows the best results.

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“…Such limit may be hard to achieve even with over-expanded downsized engines [3], so powertrain hybridisation and lean combustion concepts are possible options. Lean-burn combustion, either through conventional direct injection [4] or pre-chambers [5], has the potential to improve fuel consumption in spark ignition (SI) engines over conventional homogeneous stoichiometric charging [6]. The gains in fuel consumption resulted from lower pumping losses and higher ratio of specific heats are claimed in the range from 20 to 30% [7,8].…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of the air–fuel charging process in a four-valve supercharged two-stroke cycle GDI engine

Nora

Martins

Machado

et al. 2019

J Braz. Soc. Mech. Sci. Eng.

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Fuel consumption standards imposed in several countries for the next years have prompted the development of hybrid passenger cars with ever smaller internal combustion engines. In such powertrain, fuel consumption is as important as engine packaging and power density, so two-stroke engines may be an option due to their higher combustion frequency compared to four-stroke engines. Therefore, the present research investigates the air-fuel charging process of an overhead four-valve direct injection supercharged engine operating in the two-stroke cycle. The optimum start of fuel injection was evaluated for commercial gasoline by means of indicated and combustion efficiencies where a trade-off was found between early and late fuel injections. By advancing the injection timing, more fuel was prone to short circuit to the exhaust during the valve overlap, while late injections resulted in poor charge preparation. The gas exchange parameters, i.e. charging and trapping efficiencies, were obtained from seventy operating points running at fuel-rich conditions. The Benson-Brandham mixing-displacement scavenging model was then fit to the experimental data with a coefficient of determination better than 0.95. With such model, the air trapping and charging efficiencies could be estimated solely based on the scavenge ratio and exhaust lambda, regardless of the engine load, speed, or air/fuel ratio employed. Further twenty-five different lean-burn testing points were tested to certify the proposed methodology applied to the poppet valve two-stroke engine. The in-cylinder lambda was calculated and found different from the exhaust lambda due to mixing between burned gases and intake air during the scavenging process.

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Split injection in a homogeneous stratified gasoline direct injection engine for high combustion efficiency and low pollutants emission

Cited by 49 publications

References 21 publications

Investigation of multistage injection strategies in a DISI engine fueled with methane under stratified charge lean combustion conditions

Investigation of multistage injection strategies in a DISI engine fueled with methane under stratified charge lean combustion conditions

Flame Front and Burned Gas Characteristics for Different Split Injection Ratios and Phasing in an Optical GDI Engine

Experimental investigation of the air–fuel charging process in a four-valve supercharged two-stroke cycle GDI engine

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