High Bandwidth Heat Transfer Measurements in an Internal Combustion Engine Under Low Load and Motored Conditions
High Bandwidth Heat Transfer Measurements in an Internal Combustion Engine Under Low Load and Motored Conditions

Author:

Publisher:

Published: 2003

Total Pages: 0

ISBN-13:

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Heat transfer between the working fluid and the combustion chamber in an internal combustion engine is one of the most important parameters for cycle simulation and analysis. The heat transfer influences the in-cylinder pressure and temperature levels, engine efficiency, and exhaust emissions. Most of the current research carried out on combustion chambers focuses on gas temperature measurement by Coherent Anti-Stokes Raman Scattering (CARS) and heat transfer measurement by thermocouples. Heat transfer measurement by thermocouples leads to poor bandwidths and large uncertainties. A more advanced experimental technique for heat transfer measurement used in gas-turbine engine research, platinum thin film resistance thermometers, was recently employed in a single cylinder engine. Heat transfer rate measurements were successfully obtained on the piston surface and cylinder head exposed to the combustion gases. The thin film gauge system has a frequency response of around 100kHz and therefore can track the heat transfer rate changes on the piston surface and cylinder head adequately. Measurements taken with the engine motored and at low load are presented and discussed. (13 figures, 12 refs.).

The Transformation of Heat in an Engine
The Transformation of Heat in an Engine

Author: Kurt Neumann

Publisher:

Published: 1929

Total Pages: 68

ISBN-13:

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This report presents a thermodynamic basis for rating heat engines. The production of work by a heat engine rests on the operation of supplying heat, under favorable conditions, to a working fluid and then taking it away.

Heat-transfer Processes in Liquid-cooled Engine Cylinders
Heat-transfer Processes in Liquid-cooled Engine Cylinders

Author: Benjamin Pinkel

Publisher:

Published: 1945

Total Pages: 64

ISBN-13:

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An analysis based on forced-convection heat-transfer theory, similar to the analysis presented for air-cooled engines in NACA Report No. 612, is made of the cooling processes in liquid-cooled engine cylinders. Semi-empirical equations that relate the average head and barrel temperatures with the primary engine and coolant parameters are derived.

Heat and Mass Transfer in Gasoline and Diesel Engines
Heat and Mass Transfer in Gasoline and Diesel Engines

Author: Dudley Brian Spalding

Publisher: Core/Mechanical

Published: 1989

Total Pages: 766

ISBN-13:

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The editors explain that the classical formulae and techniques for predicting heat flow do not apply to the unique conditions found in reciprocating engines. They warn the reader--presumed to be aspiring designers of more efficient and less polluting engines--that although these papers, from every country where engineering is practiced, contain nearly all the available knowledge on the subject, no definitive answers emerge, no breakthroughs loom around the next equation. The topics include the transfer of engine heat and of external heat, numerical flow simulation, applications and devices, ignition and quenching, and measurement techniques. Annotation copyrighted by Book News, Inc., Portland, OR

High-output Diesel Engine Heat Transfer
High-output Diesel Engine Heat Transfer

Author: Eric Michael Gingrich

Publisher:

Published: 2020

Total Pages: 0

ISBN-13:

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High-output diesel engine heat transfer was investigated using a single-cylinder research engine. Engine operating conditions near 30 bar IMEPg and 250 bar in-cylinder pressure were tested. This study had three primary goals. The first was to compare local piston heat transfer, based on fast-response piston surface temperature data, to global engine heat transfer based on thermodynamic data. A wireless telemetry system was used to acquire fast-response piston surface temperature data, from which heat flux was calculated. The local measurements were then spatially averaged to find total heat transfer, which agreed relatively well with the global measurements. In the second part of this research, thermal barrier coatings of various thickness and surface roughness were applied to the piston crown. Three coated pistons were tested. Coatings with higher roughness did not show any statistically significant improvement to engine performance when compared to the metal baseline piston, and produced higher filter smoke numbers. The lower roughness coated piston showed an increase of gross indicated thermal efficiency of up to 3.5 % (relative) compared to the metal baseline piston for some operating conditions. The increase in efficiency was found to correlate with additional late-cycle apparent heat release rate and a reduction in in-cylinder heat transfer. In the third part of this research, a new instantaneous spatially averaged heat transfer correlation was developed using the local heat flux data. Previous correlations are based on the correlation of Nusselt and Reynolds numbers. The new correlation included an additional term, dimensionless chemical energy release rate. The new term was derived from dimensional analysis, which should enable similitude for diesel engines. A new interpretation of the characteristic velocity, as found in the Reynolds number, was developed and included the integrated fuel mass injection rate. The existing and new correlations were calibrated to the experimental data by minimizing the least squares error. On average, the new formulation was found to match the experimental data better than the existing models.