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Examination of Discrete Dynamics Model for Diesel Combustion and Model-Based Feedback Control System (Second Report)

Keio University-Shoma Tsuboi, Akira Kojima, Mina Nishi, Norimasa Iida
Toyota Motor Corporation-Ryo Hasegawa
Published 2015-09-01 by SAE International in United States
The dynamics model and model-based controller (LQG servo controller) have been constructed to improve performance of diesel engine in transient condition. The input parameters of the model are fuel quantity of main injection, timing of main injection, fuel quantity of pilot injection, timing of pilot injection, external EGR ratio and boost pressure. The parameters that are succeeded between cycles to express transient condition are residual gas temperature and of residual oxygen. In the model, one cycle is discretized into 10 representative points. The precision of the accuracy of the model and the responsiveness of the controller were confirmed.
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Low Cooling Losses and Low Emission Analysis of Small Bore Diesel Engine Combustion

Toyota Motor Corporation-Kentaro Nishida, Takeshi Hashizume, Ryo Hasegawa, Takashi Ogawa
Published 2015-09-01 by SAE International in United States
Small bore diesel engines often adopt a two-valve cylinder head and a non-central injector layout to expand the port flow passage area. This non-central injector layout causes asymmetrical gas flow and fuel distribution, resulting in worse heat losseses and a less homogenous fuel-air mixture than an equivalent four-valve cylinder head layout with a central injector. To improve these problems Toyota applied a new concept which was characterized by tapered shape design on the upper portion of the piston and low compression ratio to achieve more homogeneous gas flow and fuel-air mixture. This paper describes the impact of new combustion concept and the mechanism of the improvement by 3D-CFD analysis and optical measurement.
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Small Bore Diesel Engine Combustion Concept

Toyota Motor Corporation-Kentaro Nishida, Takashi Ogawa, Takeshi Hashizume, Shinobu Ishiyama, Ryo Hasegawa
Published 2015-04-14 by SAE International in United States
Small bore diesel engines often adopt a two-valve cylinder head and a non-central injector layout to expand the port flow passage area. This non-central injector layout causes asymmetrical gas flow and fuel distribution, resulting in worse heat losses and a less homogenous fuel-air mixture than an equivalent four-valve cylinder head layout with a central injector. This paper describes the improvement of piston bowl geometry to achieve a more homogeneous gas flow and fuel-air mixture. This concept reduced fuel consumption by 2.5% compared to the original piston bowl geometry, while also reducing NOx emissions by 10%.
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Development of Closed-Loop Robust Control System for Diesel Engines - Combustion Monitoring by Crank Angular Velocity Analysis and its Applications -

Toyota Motor Corporation-Yukitoshi Aoyama, Ryo Hasegawa, Tomomi Yamada, Takekazu Itoh, Terutoshi Tomoda, Yuichi Shimasaki
Published 2012-04-16 by SAE International in United States
Closed-loop robust control system that can monitor combustion state and control it into optimal state using crank angular velocity analysis was established. The system can be constructed without any change of the current hardware. It can avoid engine stall, deterioration of drivability and white smoke emission by misfire after filling low cetane fuels. This study was attempted to grasp the frequency characteristics of crank angular velocity both normal combustion and misfire with FFT (Fast Fourier Transform) and Wavelet Transform. FFT used for frequency analysis is generic method to acquire the frequency characteristics of steady oscillation, however is unsuitable for acquiring the frequency characteristics of transient oscillation. Therefore authors adopted Wavelet Transform and succeeded in grasping the phenomenon in misfiring in time sequential. With this knowledge, this study was attempted to determine the combustion instability by extracting frequency element of the 0.5 order of engine speed that is the characteristic frequency element in misfiring from pulse signal of the crank angle sensor with digital filters. With this method, misfire and combustion instability with white smoke caused…
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Improvement in DME-HCCI Combustion with Ethanol as a Low-Temperature Oxidation Inhibitor

SAE International Journal of Fuels and Lubricants

Hokkaido Univ.-Hu Zhang, Ryo Hasegawa, Hideyuki Ogawa
  • Journal Article
  • 2011-01-1791
Published 2011-08-30 by SAE International in United States
Port injection of ethanol addition as an ignition inhibitor was implemented to control ignition timing and expand the operating range in DME fueled HCCI combustion. The ethanol reduced the rate of low-temperature oxidation and consequently delayed the onset of the high-temperature reaction with ultra-low NOx over a wide operating range. Along with the ethanol addition, changes in intake temperature, overall equivalence ratio, and engine speed are investigated and shown to be effective in HCCI combustion control and to enable an extension of operation range. A chemical reaction analysis was performed to elucidate details of the ignition inhibition on low-temperature oxidation of DME-HCCI combustion.
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Effects of RME30 on Exhaust Emissions and Combustion in a Diesel Engine

Toyota Motor Corporation-Kaori Yoshida, Satoshi Taniguchi, Koji Kitano, Yukihiro Tsukasaki, Ryo Hasegawa, Ichiro Sakata
Published 2008-10-06 by SAE International in United States
Considering the popularity of biodiesel fuels for diesel vehicles, the impacts of rapeseed oil methyl ester (RME), which is the most utilized biodiesel fuel in Europe, on tailpipe emissions from a diesel passenger car was investigated. In this study, 30% RME blended diesel fuel (RME30) was used and the comparison of tailpipe emissions between RME30 and a reference diesel fuel was conducted using a test vehicle with the latest engine and aftertreatment system.The results of the investigation reveal that RME30 generates about the same amount of NOx in tailpipe emissions as diesel fuel, and less HC, CO, and PM. These phenomena occurred in spite of attaching catalysts to the test vehicle, and therefore suggesting that the NOx conversion efficiency of the catalysts for RME30 is equal to that for diesel fuel.The injection rate for RME30 was the same as that for diesel fuel. As for spray characteristics, spray penetration for RME30 at high temperature and high pressure condition tended to be slightly stronger than that for diesel fuel, but the effect is thought to be…
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Quantitative Analysis of the Relation between Flame Structure and Turbulence in HCCI Combustion by Two-Dimensional Temperature Measurement

Lund University-Marcus Aldén, Bengt Johansson
Toyota Motor Corp.-Ryo Hasegawa, Ichiro Sakata
Published 2008-04-14 by SAE International in United States
The structure of HCCI (homogeneous charge compression ignition) combustion flames was quantitatively analyzed by measuring the two-dimensional gas temperature distribution using phosphor thermometry. It was found from the relation between a turbulent Reynolds number and Karlovitz number that, when compared with the flame propagation in an S.I. engine, HCCI combustion has a wider flame structure with respect to the turbulence scale. As a result of our experimentation for the influence of low temperature reaction (LTR) using two types of fuel, it was also confirmed that different types of fuel produce different histories of flame kernel structure.
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Two-Dimensional Temperature Measurements in Engine Combustion Using Phosphor Thermometry

Lund University-Gustaf Särner, Mattias Richter, Marcus Aldén, Bengt Johansson
Toyota Motor Corp.-Ryo Hasegawa, Ichiro Sakata
Published 2007-07-23 by SAE International in United States
A phosphor thermometry, for measurements of two-dimensional gas-phase temperature was examined in turbulent combustion in an engine. The reasonable temperature deviation and the agreement with calculated data within 5% precision were achieved by single-shot images in the ignition process of compression ignition engine. Focusing on the local flame kernel, the flame structure could be quantitatively given by the temperature. It became evident that the HCCI flame kernels had 1-3 mm diameter and the isolated island structures. Subsequently, the HTR zone consisted of the combined flame kernels near TDC.
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Fuel Effects on Ion Current in an HCCI Engine

Division of Combustion Engines, Lund Institute of Technology-Andreas Vressner, Anders Hultqvist, Per Tunestål, Bengt Johansson
Toyota Motor Corp.-Ryo Hasegawa
Published 2005-05-11 by SAE International in United States
An interest in measuring ion current in Homogeneous Charge Compression Ignition (HCCI) engines arises when one wants to use a cheaper probe for feedback of the combustion timing than expensive piezo electric pressure transducers. However the location of the ion current probe, in this case a spark plug, is of importance for both signal strength and the crank angle position where the signal is obtained. Different fuels will probably affect the ion current in both signal strength and timing and this is the main interest of this investigation. The measurements were performed on a Scania D12 engine in single cylinder operation and ion current was measured at 7 locations simultaneously. By arranging this setup there was a possibility to investigate if the ion current signals from the different spark plug locations would correlate with the fact that, for this particular engine, the combustion starts at the walls and propagates towards the centre of the combustion chamber. The fuels investigated were isooctane, n-heptane, PRF80, gasoline, diesel, ethanol and methanol. A special interest was how the ion…
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Optical Diagnostics of HCCI and UNIBUS Using 2-D PLIF of OH and Formaldehyde

Division of Combustion Engines, Lund Institute of Technology-Leif Hildingsson, Håkan Persson, Bengt Johansson
Division of Combustion Physics, Lund Institute of Technology-Robert Collin, Jenny Nygren, Mattias Richter, Marcus Aldén
Published 2005-04-11 by SAE International in United States
Simultaneous OH- and formaldehyde planar-LIF measurements have been performed in an optical engine using two laser sources working on 283 and 355 nm, respectively. The measurements were performed in a light duty Diesel engine, using n-heptane as fuel, converted to single-cylinder operation and modified for optical access. It was also equipped with a direct injection common rail system as well as an EGR system.The engine was operated in both HCCI mode, using a single fuel injection, and UNIBUS (Uniform Bulky Combustion System) mode, using two injections of fuel with one of the injections at 50 CAD before TDC and the other one just before TDC.The OH and formaldehyde LIF images were compared with the heat-release calculated from the pressure-traces. Analyses of the emissions, for example NOx and HC, were also performed for the different operating conditions.
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