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The combination method for measuring the oil film thickness and velocity is proposed. The oil film thickness is measured by laser induced fluorescence (LIF) method and its velocity is measured by particle image velocimetry (PIV). A model engine is employed in order to check the LIF measurement for oil film thickness, and an optical access engine based on production engine is utilized for both measurements of oil film thickness and velocity. In the combination method, LIF images are used in the PIV measurement instead of particle images. From the results, the oil film thickness and velocity can be measured simultaneously by the combination method utilizing only LIF dye. The oil film thickness and velocity are presented along with crank angle of the engine under the motoring operation. The oil film velocity is also measured under the firing operation.

The fuel adhesion to the surfaces of the intake port, cylinder wall and piston head is one of the common phenomena in turbocharged gasoline injection engine. It causes super-knock, unburned HC and oil dilution. In this study, the fuel thickness and amount of adhering fuel to the oil film on the flat plate are measured by laser induced fluorescence (LIF) method and high-speed camera. As a result, they can be evaluated quantitatively. An influence of the oil film on evaporation of the fuel is also clarified.

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.

Velocity measurement of an intermittent high-speed flow inside a micro wave rotor cell was carried out using a laser Doppler anemometry (LDA). The cell is 3 × 3 mm rectangular tube, whose length is 42 mm. The pressure ratio and rotor speed of the wave rotor were set at 2.5 and 5,000 rpm, respectively. Ethanol droplets were seeded into the flow as scattering particles. By use of laser beam expanders, the probe volume of the LDA optics was minimized, and sub-millimeter special resolution is realized while a wide velocity range (-100 to 300 m/s) is kept. It is shown that the velocity histories at local positions inside the wave rotor cell can be obtained with the LDA optics. The rapid velocity increase and decrease, due to the primary and secondary shock waves, are observed, and the propagation speed of the shock waves was estimated. It is shown that the velocity profile inside the cell is flat and that the boundary layer thickness inside the cell is smaller than 0.5 mm.

Observations of the scavenging flow field have been made in a modified poppet-valved two-stroke engine with a transparent cylinder. Four kinds of cylinder heads with different port configuration were created to analyze their effects on the scavenging flow and develop new scavenging concepts. A mineral oil fog discharge system was used to visualize the air flow during the scavenging process. All of the images were recorded by a high speed video camera which show the development of the scavenging processes and clearly indicate the scavenging jet structure, the tumble pattern and the location of re-circulation regions. The analyses allow us to judge the quality of the scavenging processes. The small changes in port geometry could significantly affect the scavenging flow. Tumble as well as swirl should be considered as main means to organize the scavenging flow in order to avoid short-circuiting losses and create condition favorable to combustion.

High-pressure fuel spray proposed for direct injection gasoline engine was evaluated by means of a phase Doppler anemometer (PDA) and flow visualization. The intermittent fuel spray from a swirl type injector was injected in a constant volume chamber under various conditions of backpressure and ambient temperature. The backpressures were set to 0, 0.5 and 1 MPa in gauge pressure. The ambient temperatures were set to 293, 373, 423 and 473K. Normal-heptane was used as a fuel with injection pressure of 10MPa and injection frequency of 10Hz. Spray characteristics of the temporal and spatial distributions of the mean velocity and the mean diameter were measured by the PDA. Visualizations of spray were also made by a particle image velocimetry (PIV). The experimental results show the effects of backpressure and ambient temperature on the spray shape and characteristics of droplet size and velocity distributions.

A high-pressure swirl type fuel spray has been experimentally analyzed by using a phase Doppler anemometer (PDA). The experiments were mainly made under the injection pressure of 5MPa and injection frequency of about 46Hz. The PDA data was obtained in a two-dimensional plane and arranged by the ensemble-averaged method along the injection phase angle. The arranged data of mean velocity and Sauter mean diameter were visualized for demonstration. Time-dependent centerline velocity at the injection pipe was also measured by means of laser Doppler anemometer (LDA). Swirl injector operating at injection frequencies of 22 and 46 Hz generates oscillating flow in the pipe under injection pressure from 4 to 7 MPa. The time-series of centerline velocity was used to reconstruct the time-series of instantaneous pressure gradient and flow rate in the pipe.

In CFD (Computational Fluid Dynamics) verification of vehicle aerodynamics, detailed velocity measurements are required. The conventional 2D-PIV (Two Dimensional Particle Image Velocimetry) needs at least twice the number of operations to measure the three components of velocity ( u,v,w ), thus it is difficult to set up precise measurement positions. Furthermore, there are some areas where measurements are rendered impossible due to the relative position of the object and the optical system. That is why the acquisition of detailed velocity data around a vehicle has not yet been attained. In this study, a detailed velocity measurement was conducted using a 3D-PIV measurement system. The measurement target was a quarter scale SAE standard vehicle model. The wind tunnel system which was also designed for a quarter scale car model was utilized. It consisted of a moving belt and a boundary suction system.