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Technical Paper
Syuichi Ezaki, Michihiko Masuda, Hiroya Fujita, Souichi Hayashi, Yukio Terashima, Katsuhiko Motosugi
An investigation was made into the effects of valve lifter material on fuel consumption and engine noise. It was found that the use of aluminum not only improves fuel economy but also reduces valve-train chatter because it is lighter in weight and less hard than steel. The stresses to which the valve lifters are subjected and their surface temperatures were measured in bench tests, and durability tests were conducted to ascertain the problems which might be expected. Based on the results of these tests, the shape was modified, a new aluminum alloy was developed and a coating was applied to the surface. The aluminum valve lifters thus developed were found to be as durable as conventional steel lifters and have been used in the new Toyota V8 engine (IUZ type).
Journal Article
Hidemasa Kosaka, Yoshifumi Wakisaka, Yoshihiro Nomura, Yoshihiro Hotta, Makoto Koike, Kiyomi Nakakita, Akio Kawaguchi
The aim of this work is to investigate the possibility of heat insulation by “Temperature Swing”, that is temperature fluctuation, on combustion chamber walls coated with low-heat-conductivity and low-heat-capacity materials. Adiabatic engines studied in the 1980s, such as ceramic coated engines, caused constantly high temperature on combustion wall surface during the whole cycle including the intake stroke, even if it employed ceramic thermal barrier coating methods. This resulted in increase in NOx and Soot, decrease in volumetric efficiency and combustion efficiency, and facilitated the occurrence of engine knock. On the other hand, “Temperature Swing” coat on the combustion chamber walls leads to a large change in surface temperature. In this case, the surface temperature with this insulation coat follows the transient gas temperature, which decreases heat loss with the prevention of intake air heating, and also which is expected to prevent NOx and Soot from increasing.
Technical Paper
Noriyuki Naganuma, Kenji Fujino, Tsuyoshi Yamazaki, Gen Ogino, Koji Saito, Hiromi Kawai
Some magnesium detergents in engine oil are reported to form sludge of needle crystals in the presence of carbon dioxide and water We tried to reproduce needle crystals in a beaker test and studied factors in needle crystal formation by magnesium detergents We found that overbased components of magnesium detergents dissolved in carbonic acid water formed needle crystals recrystallizing We also found the quantities of needle crystals increased when both carbon dioxide and water content in oil increased Moreover we clarified the quantities and sizes of needle crystals differed by magnesium detergents
Technical Paper
Akio Kawaguchi, Hiroki Iguma, Hideo Yamashita, Noriyuki Takada, Naoki Nishikawa, Chikanori Yamashita, Yoshifumi Wakisaka, Kenji Fukui
Abstract To improve fuel efficiency of engines, cooling heat loss is one of the most dominant losses among the various engine losses to reduce. The present work proposes a new heat insulation concept in combustion chamber, "TSWIN (Thermo-Swing Wall Insulation Technology)" that can reduce heat loss to the coolant without any sacrifice in other engine performances. Surface temperature of insulation coat on combustion chamber wall changes rapidly, according with the fluctuating temperature of in-cylinder gas. Reduced temperature differences between them lead to lower heat transfer. During the intake stroke, surface temperature of the insulation coat goes down rapidly, and prevents intake air heating. To realize the scheme mentioned above, a new insulation material with both low thermal conductivity and low volumetric heat capacity, "SiRPA (Silica Reinforced Porous Anodized Aluminum)" was developed and applied on the top surface of the piston.
Technical Paper
Kenji Kawazu, Mika Kai, Keiji Koike, Makoto Imada, Kazumi Yasuda
The sense of touch, compared with the visual sense or the auditory sense, is difficult to describe with physical quantities. Since positive movements like pushing or friction depend on personal feeling, it is difficult to quantify. Despite few studies by the paint industry on the sense of touch, it has been studied extensively in the fabric and construction industries. For this study, first, we proposed a hypothetical formula based on literature research. Next, we carried out questionnaires for painted panels, researched physical quantities, and analyzed the results. Finally, we derived the world’s first formula (S) for quantifying the “soft feel” of painted panels. In addition, we surveyed the favorable feel in order to set target values for our formula. Paints are currently being developed using these values.
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