Effect of Bioethanol Blended Diesel Fuel and Engine Load on Spray, Combustion, and Emissions Characteristics in a Compression Ignition Engine

Abstract

This study investigates the effect of engine load condition on the injection spray, combustion, and exhaust emissions characteristics of a diesel–bioethanol blended fuel diesel engine. In this study, the injection characteristics, such as the effective flow diameter and the effective flow velocity, were calculated from the nozzle flow model. The macroscopic spray characteristics of diesel–bioethanol fuels were measured and analyzed using a spray visualization system. Using a four-cylinder test engine with 1.5 L of displacement, the combustion pressure, heat release, and emission characteristics were measured and analyzed. In addition, properties of blended fuel were measured and analyzed. This study revealed that the physical properties (density, viscosity, and surface tension) and chemical properties (cetane number, heating value, and distillation) of diesel–bioethanol blended fuels generally decreased with increased bioethanol content. The increase in bioethanol fuel resulted in easy vaporization at the same temperature condition. After energizing, the increase of engine load caused an increase in spray tip penetration. The spray cone angle was mainly affected by the blending of bioethanol, not the engine load. The increase of engine load led to a decrease of ignition delay by the high gas temperature, and it also caused an increase in the combustion duration for the same fuel amount. In the exhaust emissions, the increase of engine load affected the increase in both the NO x and ISNO x emissions, the decrease of CO and HC emissions. At a high engine load, CO and HC emissions were quite similar in D100, DE10, and DE20 fuels due to the increased oxygen content.

A Review on Spray Characteristics of Bioethanol and Its Blended Fuels in CI Engines

“…Only two studies in the literature were found in relation to surfacte tension of e-diesel. The exponential decrease of the surface tension from E0 to E25 in e-diesel was found by Li et al (24) The surface tension of e-diesel exponentially decreased with increase in bioethanol content up to 20% of bioethanol, and thereafter addition of bioethanol didn't affect the surface tension of e-diesel (29) . It should be pointed out that the exact value of surface tension for the same e-diesel was widely different from two studies, due to different surface tension of diesel tested in the experiment, respectively.…”

“…Density: Torres-Jimenez et al (28) found in the ediesel from 0 to 15% of ethanol that density of e-diesel was decreased with increase in bioethanol content. However, density values for all samples tested are within the standard range (limit of EN 590 Min / Max = 820 / 845 kg/m 3 at the reference temperature of 288 K. This means that there will be no problems related to atomization of e-diesel The measurement results by Park et al (29) showed that the density of ediesel with 10% of biodiesel (soybean oil methyl ester) as emulsifier generally decreased with the increase in bioethanol content from 0 to 50%. However, density values for more than 30% of bioethanol content are not within the standard range of EN 590.…”

“…It is known that the addition of ethanol to diesel fuel from 0% to 50% linearly decreases kinematic viscosity of e-diesel with 10% of biodiesel as an emulsifier. An increase in fuel temperature resulted in decrease in kinematic viscosity (29) . Fuels with lower viscosity and surface tension can help in better atomization and lead to lower droplet diameter (30) .…”

“…As same case with Park et al (54) , the discussion on the effect of blending ratio on macroscopic spray characteristics is not suitable because DE0 didn't mixed with biodiesel. In addition, the data and experimental results for the same ethanol blended fuels and engine load conditions in this study were included in the work of Park et al (29) which is recently pub-…”

Using Parametrized Finite Combustion Stage Models to Characterize Combustion in Diesel Engines

“…Heat release analysis is an important tool in the research of the combustion process in diesel engines. − Theoretical heat release can be obtained through, for example, CFD models of the combustion, but here, the heat release is calculated from in-cylinder pressure measurements based on a single-zone combustion model. Following a heat release calculation, there are several methods to investigate the combustion process in the diesel engine.…”