Ignition Delay in a Diesel Engine

Lakshminarayanan, P. A.; Aghav, Yogesh V.

doi:10.1007/978-90-481-3885-2_5

Cited by 22 publications

(9 citation statements)

References 15 publications

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“…The SoI and SoC expressions expressed in this figure show the ignition start and the start of the combustion, respectively. Ignition delay, observed as a rapid increase in pressure or inception of heat release, described as time interval from start of fuel injection to the start of combustion (Lakshminarayanan et al, 2010). Late start of combustion results in long ignition delay as expected.…”

Section: Cylinder Pressures and Heat Release Ratementioning

confidence: 66%

The experimental investigation of diesel fuel-biofuel blends at different injection pressures in a DI diesel engine

Örs

Ciniviz²,

Kul³

et al. 2021

JER is an international, peer-reviewed journal that publishes f

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In this study, it was aimed to investigate the effects of a diesel-biodiesel blend (B20) and a diesel-biodiesel-bioethanol blend (BE5) on combustion parameters in addition to engine performance and exhaust emissions compared with diesel fuel. Parameters included in the evaluation was brake specific fuel consumption, brake thermal efficiency, CO, CO2, HC, NOx, smoke opacity emissions and finally cylinder pressure, heat release rate, ignition delay, some key points of the combustion phases such as start of ignition, start of combustion, CA50 and CA90 and combustion duration. Engine tests were conducted at different injection pressures of 170 bar, 190 bar, which is the original injection pressure, and 220 bar by the engine being loaded by 25, 50, 75 and 100% for the assessment of engine performance and exhaust emissions. For combustion evaluation, the data obtained at 1400 rpm, maximum torque-speed, and 2800 rpm, maximum power-speed were used, while the injection pressures were set to 170, 190 and 220 bar under full load condition. According to test results, the better performance characteristics, exhaust emissions and combustion behaviour of engine were obtained with the use of BE5 at high injection pressure. So, BE5 fuel improved brake specific fuel consumption by about 7% and brake thermal efficiency by about 6% compared to B20. In addition, while the emission values of BE5 gave better results than diesel fuel, it reduced the NOx and smoke emissions of B20 by approximately 1.4% and 6.4% respectively. Moreover, it has achieved a reduction in smoke emission of up to 45% compared to diesel fuel.

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Section: Cylinder Pressures and Heat Release Ratementioning

confidence: 66%

The experimental investigation of diesel fuel-biofuel blends at different injection pressures in a DI diesel engine

Örs

Ciniviz²,

Kul³

et al. 2021

JER is an international, peer-reviewed journal that publishes f

View full text Add to dashboard Cite

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“…In general, the delay time defined by τ 5pc covers simultaneous, interacting processes that are both of a physical nature, including liquid-fuel atomization, evaporation and mixing with air, as well as the chemical reactions leading to autoignition (pre-ignition chemistry) [68], so it is difficult to compare this to separate timescales, especially in cases where the underlying process timescales are of the same order. On the other hand, Ciezki and Adomeit [71] observed non-linear behaviour in the lower temperature range of 650 -1000 K and the non-linearity was attributed to a transition in the reaction kinetics mechanism.…”

Section: Autoignition Delay Timesmentioning

confidence: 99%

Autoignition of an n-heptane jet in a confined turbulent hot coflow of air

Gupta

Markides

2020

Experimental Thermal and Fluid Science

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The autoignition of a continuous, single jet of pure liquid n-heptane injected concentrically and axisymmetrically from a water-cooled circular nozzle into a confined turbulent hot coflow (CTHC) of air at atmospheric pressure has been investigated experimentally at air temperatures up to 1150 K and velocities up to 40 m/s. The aim of this work was to examine the emergence of liquid-fuel autoignition in the presence of flow, mixture and phase inhomogeneities, to which end, the velocity, temperature and fuel-droplet fields inside the CTHC reactor were characterized in a series of dedicated measurement campaigns. Distinct phenomena were identified concerning the emergence of various regimes: no autoignition, random spots, and continuous flame. In the random spots regime, autoignition appeared in the form of well-defined, discrete localized spots occurring randomly within the reactor, similar to observations in a similar apparatus with gaseous fuels [1][2][3][4]. High-speed optical measurements of these random spots were made from which the autoignition locations/lengths were measured, and then used to infer average autoignition delay, or residence, times from injection based on the bulk air velocity. An increase in the air temperature moved the region of autoigniting spots closer to the injector nozzle, thus decreasing the autoignition length and also decreasing the autoignition delay time. Generally, autoignition moved downstream with increasing bulk air velocity, but the delay times decreased contrary to the aforementioned earlier work with pre-vaporized n-heptane in this geometry.Of interest is the finding that at the highest investigated air velocities, the autoignition length decreased as the air velocity increased, which again deviates from the same earlier work with vaporized n-heptane. Furthermore, higher liquid injection velocities also resulted in increased autoignition lengths and times.The results from this work suggest that the turbulent inhomogeneous autoignition of liquid fuels cannot be directly predicted from chemical delay times of equivalent homogeneous systems, or even from knowledge of the turbulent inhomogeneous autoignition of single-phase (gaseous) fuels in the same reactor system (flow geometry, fuel, conditions, etc.), and that the effects of evaporation and turbulent mixing must be accounted for. The data can assist the development of advanced turbulent and multiphase reacting flow models.

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“…The process of fuel spray penetration and droplet formation can be described by jet penetration models. The duration between fuel injection and first chemical reaction is called the ignition delay . After ignition delay, the first stage is premixed combustion, which is due to the ignition of fuel air mixture prepared during the delay period .…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic modeling and validation of in‐cylinder flow in diesel engines

Neshat

Nazemian

Honnery

2019

Env Prog and Sustain Energy

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The formation of a suitable air and fuel mixture in diesel engines is one of the most important factors in quality of combustion and engine exhaust emissions. The mixture formation depends on mass transfer phenomenon inside the combustion chamber. This study presents a new thermodynamic model to simulate the mass transfer phenomenon in diesel engines. Diesel engine is simulated utilizing a thermodynamic multi zone model coupled to a semi‐detailed chemical kinetics mechanism. Heat and mass transfer submodels are linked to the multi zone model. Bulk flow and diffusion mass transfer between zones are considered in the mass transfer submodel. Bulk mass transfer simulates fluid motion between different zones caused by piston speed and difference in zonal temperature and pressure. Diffusion mass transfer occurs due only to difference in composition of different zones. The results indicate diesel engine performance and exhaust emissions can be predicted accurately applying mass transfer submodels. Bulk mass transfer mechanism has more significant effects on engine performance and emission compared to diffusion mechanism. Neglecting mass transfer submodels, calculated in‐cylinder peak pressure is under predicted and both of exhaust NOx and soot are over predicted. The rates of soot oxidation reactions decrease and rates of NOx important reactions increase when mass transfer submodels are ignored. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13146, 2019

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Ignition Delay in a Diesel Engine

Cited by 22 publications

References 15 publications

The experimental investigation of diesel fuel-biofuel blends at different injection pressures in a DI diesel engine

The experimental investigation of diesel fuel-biofuel blends at different injection pressures in a DI diesel engine

Autoignition of an n-heptane jet in a confined turbulent hot coflow of air

Thermodynamic modeling and validation of in‐cylinder flow in diesel engines

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