Determination of Thermal Conductivity and Thermal Diffusivity of S.I. Engine Combustion Chamber Deposits

• Published in: Nihon Kikai Gakkai rombunshuu. B hen Vol. 61; no. 589; pp. 3390 - 3396
• Main Authors: Hafnan, Muhammad, Nishiwaki, Kazuie
• Format: Journal Article
• Language: English; Japanese
• Published: 1995
• Subjects: Heat transfer; Internal combustion engines; Q1
• ISSN: 0387-5016; 1884-8346
• DOI: 10.1299/kikaib.61.3390

Thermal conductivity and thermal diffusivity of combustion chamber deposits in an s. i. engine have been measured to provide the data for analyzing heat transfer which is reduced by the deposits. The deposits were built-up on the surface thermocouples under different engine speeds, loads and equivalence ratios. After removing the surface thermocouples with deposits from the engine, the deposit surface temperatures were measured by an infrared technique in a test cavity installed in a motored engine and at the same time the deposit-wall interface temperatures were detected with the surface thermocouple. The thickness of the deposits was measured with a laser displacement meter. These data were used for determining thermal conductivity. Thermal diffusivity was obtained from penetration time measurements for a laser pulse emitted to the deposit surface. The results show that thermal conductivity is almost unchanged for different engine speeds, loads and equivalence ratios, while thermal diffusivity is influenced by the equivalence ratio.