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The flow rate meter based on the Laser Doppler Anemometer (LDA) has been developed to evaluate the fuel injection rate. The flow rate meter is called as LDA flow rate meter. The instantaneous flow rate has been measured at the upstream of an injector. The measured results of instantaneous flow rate are influenced by reflection pressure waves from the end of pipe. The effects of the pressure waves appear as undesirable oscillations in the results of the instantaneous flow rate. A reducing method of the oscillations is proposed as data correction. Corrected data of LDA flow rate meter have similar profiles to the results by the BOSCH-Type injection indicator. The results indicate the instantaneous injection rate can be evaluated by using the LDA flow rate meter.

The purpose of this study was to measure the distribution and volume of liquid film adhering to the walls after the injection of fuel by an injector of a port-injection engine using the laser induced fluorescence (LIF) method while changing the fuel pressure and the angle of injection, and to consider how adhesion can be reduced in order to decrease the exhaust emission of gasoline engine. Using a high-speed camera, we filmed the adhesion and evaporation of liquid film in time series. Perylene, used here as a fluorescence dye, was blended with a fuel comprising toluene and n-heptane, and the mixture was injected onto a solid surface using a port-injection injector. UVLED with a maximum output wavelength of 375 nm was used as the exciting light. To more accurately measure the volume of fuel adhesion, it was necessary to correct the unevenness of the light source.

Characteristics of PM and its compositions inside and outside of flame were required to develop reduction technologies for combustion origin PM. In this paper, relationship between PM size distribution and compositions such as soot and soluble organic fraction (SOF) of PM sampled with filter were investigated. Number distributions of PM (30 nm-10 μm) were measured using an ELPI (Electrical Low Pressure Impactor). Dry-soot and SOF in PM that was captured an individual stage of ELPI were analyzed using a combustion type PM analyzer (MEXA-1370PM). It was clarified that nuclei mode particle included more SOF than accumulation mode particle. PM characterization showed that there were many differences between in-flame PM and out-flame PM. In-flame PM contained much of low boiling point SOF and dry-soot composition was thermally unstable. Further, similarities between SOF in PM sampled with filter and gaseous hydrocarbons passing through PM filter were discussed.

The mixture formation by fuel spray impingement (OSKA system) was applied to a small direct-injection diesel engine in order to reduce the wall quenching- induced emissions, i.e., the emissions of THC and soluble organic fractions (SOF). Experiments were carried out using a single-cylinder engine, fitted with various piston cavity geometries, ran under a wide range of compression ratios and fuel injection specifications. The piston cavity was designed as a centrally located reentrant type. The combination of the high squish flow and the weak penetration of the OSKA spray was very effective in reducing harmful emissions. A short ignition delay, under the retarded fuel injection timing, was obtained because of the high compression ratio. The OSKA DI diesel engine showed reduced NOx, smoke, and THC emissions without deterioration of the fuel consumption compared to modern DI diesel engines used in automotive applications.

A six-stroke DI diesel engine proposed by the authors had second compression and combustion processes which were added on a conventional four-stroke diesel engine. This engine had the first and second power strokes before the exhaust stroke. Numerical predictions and experiments previously carried out had shown that this six-stroke diesel engine could reduce NO exhaust emission. Further, the ignition delay of the second combustion process could be shortened by a high temperature effect in the second compression stroke. This advantage of short ignition delay could be utilized for an ignition improvement of a fuel with low cetane number. In the engine system reported here, a conventional diesel fuel was supplied as the fuel of first combustion process, and in the second combustion process, methanol was supplied.

A modified drop drag (MOD) model based on the droplet deformation and breakup (DDB) model has been developed and implemented in the KIVA II code for describing fuel spray impingement against the walls of the combustion chamber in D.I. diesel engines. The model accounts for the effects of both the drop's frontal area and its drag coefficient as a function of its distortion. In the MDD model, the stochastic rotation of drops that have impacted and bounced off the wall is considered. This makes it possible to model the highly distorted drop's frontal area variation and its effect on the drag coefficient in sprays. At the same time, the distribution of sizes of drops formed from parent drops after their breakups is modeled by using a stochastic model. A modified RNG κ - ε model is also included in the present computations. The details of fuel spray impingement against a wall were investigated by using the present models.

This paper presents the effect of fuel atomization at an intake manifold on the combustion characteristics of a spark-ignition engine. Four sets of fuel-supply devices were tested which have much difference in atomization characteristics in terms of the mean droplet size ranging from wall film to 7 um S.M.D. Over the whole operatable range of mixture strength, the fuel atomization did not give any effect on BMEP, BSFC and volumetric efficiency, but had an effect on the engine stability at lean operation limit under most operating conditions. This atomization effect was shown to be systematically characterized by mapping on the ignition timing and A/F plane. The appearance of partial-burn limit on the map was successfully verified by the combustion analysis using a correlation procedure on cycle by cycle basis.

To study the characteristics of flow velocity and particle diameters in large angle conical spray proposed for hot-premixed combustion type Diesel engines, steady and unsteady conical sprays have been analyzed using laser Doppler anemometry (LDA), and phase Doppler anemometry (PDA). Three injection pressures were used in steady experiments. In unsteady experiments, the frequency of injection was 20.7 Hz and the amount of injection fuel was 10.3 mg or 25.6 mg in each cycle. Distributions of bulk velocity, fluctuation intensity of the velocity, air entrainment rate, Sauter mean diameter of particles and correlation between particle diameter and velocity of the spray were obtained.