Development of Transparent Cylinder Engines for Schlieren Observation

Fujikawa, Taketoshi; Ozasa, Toshihiro; Kozuka, Kazuhiro

doi:10.4271/881632

“…Finally, we have not yet compared the current lenscylinder-lens system to the approach taken by Toyota [20][21][22] [called the transparent collimating cylinder (TCC) by those authors]. On a conceptual level, the main difference between the two approaches is that the former separates the mechanical task of containing the cylinder pressure from the optical correction, while the latter integrates both in the same element by adapting the outer shape of the engine cylinder.…”

Section: Discussionmentioning

confidence: 95%

“…Illumination was monochromatic at 488 nm (Ar-ion laser) with the visualized region covering 67% of the 83 mm bore. A second version of the cylinder was made from quartz glass with tighter manufacturing tolerances and correspondingly improved performance [20], but in two more recent publications the acrylic version was used [21,22].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Schlieren measurements in the round cylinder of an optically accessible internal combustion engine

Kaiser

¹

,

Salazar

²

,

Hoops

³

2013

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This paper describes the design and experimental application of an optical system to perform schlieren measurements in the curved geometry of the cylinder of an optically accessible internal combustion engine. Key features of the system are a pair of cylindrical positive meniscus lenses, which keep the beam collimated while passing through the unmodified, thick-walled optical cylinder, and a pulsed, high-power light-emitting diode with narrow spectral width. In combination with a high-speed CMOS camera, the system is used to visualize the fuel jet after injection of hydrogen fuel directly into the cylinder from a high-pressure injector. Residual aberrations, which limit the system's sensitivity, are characterized experimentally and are compared to the predictions of ray-tracing software.

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“…Consequently, the application of the technique in interesting environments, such as the in-cylinder flow field of an IC engine, requires special attention. Previous attempts at using qualitative schlieren visualisation in situations where optical access is provided through curved optical surfaces in engines have been reported in [7][8][9]. One approach places appropriate lenses in front and after the curved engine cylinder windows [8], aiming to reshape the incoming parallel light when it passes through the engine cylinder.…”

Section: Introductionmentioning

confidence: 99%

Schlieren-based temperature measurement inside the cylinder of an optical spark ignition and homogeneous charge compression ignition engine

Aleiferis

¹

,

Charalambides

²

,

Hardalupas

³

et al. 2015

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Schlieren [1, 2] is a non-intrusive technique that can be used to detect density variations in a medium, and thus, under constant pressure and mixture concentration conditions, measure whole field temperature distributions.The objective of the current work was to design a schlieren system to measure line-of-sight averaged temperature distribution with the final aim to determine the temperature distribution inside the cylinder of Internal Combustion engines. In a preliminary step, we assess theoretically the errors arising from the data reduction used to determine temperature from a schlieren measurement and find that the total error, random and systematic, is less than 3%, for typical conditions encountered in the present experiments. A Z-type, curved-mirror schlieren system was used to measure the temperature distribution from a hot air jet in an open air environment in order to evaluate the method. Using the Abel transform, the radial distribution of the temperature was reconstructed from the line of sight measurements. There was good agreement in the peak temperature between the reconstructed schlieren and thermocouple measurements. Experiments were then conducted in a four-stroke, single-cylinder, optical spark ignition engine with a four-valve, pentroof-type cylinder head to measure the temperature distribution of the reaction zone of an iso-octane-air mixture. The engine optical windows were designed to produce parallel rays and allow accurate application of the technique. The feasibility of the method to measure temperature distributions in IC engines was evaluated with simulations of the deflection angle combined with equilibrium chemistry calculations that estimated the temperature of the reaction zone at the position of maximum ray deflection as recorded in a schlieren image. Further simulations showed that the effects of exhaust gas recirculation and air-to-fuel ratio on the schlieren images were minimal under engine conditions compared to the temperature effect. At 20 crank angle degrees before top dead centre (i.e. 20 crank angle degrees after ignition timing), the measured temperature of the flame front was in agreement with the simulations (730-1320 K 2 depending on the shape of the flame front). Furthermore, the schlieren images identified the presence of hot gases ahead of the reaction zone due to diffusion and showed that there were no hot spots in the unburned mixture.

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“…The lenses can be specially designed, including a detailed assessment of their aberrations, so provide flexibility in the experimental setup [9]. Alternatively, the whole engine cylinder can be manufactured in such a way as to keep the incoming light collimated through the engine [7]. In our experiments, optical access to the IC engine is provided through pentroof windows, which we specially design to maintain parallel light through the engine and, also, avoid possible complications due to relative movement between the engine and a fixed lens.…”

Section: Introductionmentioning

confidence: 99%

Using Infrared Laser Absorption to Measure Hydrocarbon Concentration in a Lean-Burn, Stratified-Charge, Spark-Ignition Engine

Charalambides

¹

,

Hardalupas

²

,

Soulopoulos

³

et al. 2015

Combustion Science and Technology

0

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Schlieren [1, 2] is a non-intrusive technique that can be used to detect density variations in a medium, and thus, under constant pressure and mixture concentration conditions, measure whole field temperature distributions.The objective of the current work was to design a schlieren system to measure line-of-sight averaged temperature distribution with the final aim to determine the temperature distribution inside the cylinder of Internal Combustion engines. In a preliminary step, we assess theoretically the errors arising from the data reduction used to determine temperature from a schlieren measurement and find that the total error, random and systematic, is less than 3%, for typical conditions encountered in the present experiments. A Z-type, curved-mirror schlieren system was used to measure the temperature distribution from a hot air jet in an open air environment in order to evaluate the method. Using the Abel transform, the radial distribution of the temperature was reconstructed from the line of sight measurements. There was good agreement in the peak temperature between the reconstructed schlieren and thermocouple measurements. Experiments were then conducted in a four-stroke, single-cylinder, optical spark ignition engine with a four-valve, pentroof-type cylinder head to measure the temperature distribution of the reaction zone of an iso-octane-air mixture. The engine optical windows were designed to produce parallel rays and allow accurate application of the technique. The feasibility of the method to measure temperature distributions in IC engines was evaluated with simulations of the deflection angle combined with equilibrium chemistry calculations that estimated the temperature of the reaction zone at the position of maximum ray deflection as recorded in a schlieren image. Further simulations showed that the effects of exhaust gas recirculation and air-to-fuel ratio on the schlieren images were minimal under engine conditions compared to the temperature effect. At 20 crank angle degrees before top dead centre (i.e. 20 crank angle degrees after ignition timing), the measured temperature of the flame front was in agreement with the simulations (730-1320 K 2 depending on the shape of the flame front). Furthermore, the schlieren images identified the presence of hot gases ahead of the reaction zone due to diffusion and showed that there were no hot spots in the unburned mixture.

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Development of Transparent Cylinder Engines for Schlieren Observation

Cited by 19 publications

References 8 publications

Schlieren measurements in the round cylinder of an optically accessible internal combustion engine

Schlieren measurements in the round cylinder of an optically accessible internal combustion engine

Schlieren-based temperature measurement inside the cylinder of an optical spark ignition and homogeneous charge compression ignition engine

Using Infrared Laser Absorption to Measure Hydrocarbon Concentration in a Lean-Burn, Stratified-Charge, Spark-Ignition Engine

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