Analysis of cylinder-pressure-indicator diagrams showing effects of mixture strength and spark timing

Description:

An investigation was made to determine the effect of mixture strength and of normal as well as optimum spark timing on the combustion, on the cylinder temperature, and on the performance characteristics of an engine. A single-cylinder test unit utilizing an air-cooled cylinder and a carburetor and operating with gasoline having an octane rating of 92 was used. The investigation covered a range of fuel-air ratios from 0.053 to 0.118. Indicator diagrams and engine-performance data were taken for each change in engine conditions. Examination of the indicator shows that for fuel-air ratios less than and greater than 0.082 the rate and the amount of effective fuel burned decreased. For a fuel-air ratio of 0.118 the combustion efficiency was only 58 percent. Advancing the spark timing increased the rate of pressure rise. This effect was more pronounced with leaner mixtures.

Creator(s):
Creation Date: August 1, 1940
Partner(s):
UNT Libraries Government Documents Department
Collection(s):
National Advisory Committee for Aeronautics Collection
Technical Report Archive and Image Library
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Total Uses: 103
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Creator (Author):
Creator (Author):
Date(s):
  • Creation: August 1, 1940
Description:

An investigation was made to determine the effect of mixture strength and of normal as well as optimum spark timing on the combustion, on the cylinder temperature, and on the performance characteristics of an engine. A single-cylinder test unit utilizing an air-cooled cylinder and a carburetor and operating with gasoline having an octane rating of 92 was used. The investigation covered a range of fuel-air ratios from 0.053 to 0.118. Indicator diagrams and engine-performance data were taken for each change in engine conditions. Examination of the indicator shows that for fuel-air ratios less than and greater than 0.082 the rate and the amount of effective fuel burned decreased. For a fuel-air ratio of 0.118 the combustion efficiency was only 58 percent. Advancing the spark timing increased the rate of pressure rise. This effect was more pronounced with leaner mixtures.

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Contributor(s):
Serial Title: NACA Technical Notes
Partner:
UNT Libraries Government Documents Department
Collection:
National Advisory Committee for Aeronautics Collection
Collection:
Technical Report Archive and Image Library
Identifier:
Resource Type: Report
Format: Text
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Access: Public
Statement: No Copyright, Unclassified, Unlimited, Publicly available