1964-01-01

Engine Roughness - the Key to Lower Octane Requirement 640057

Improvement of engine octane requirement by combustion chamber design has been blocked by engine roughness noise. This noise is caused by high rates of pressure rise in the cylinder due to fast-burn combustion. This produces transient noise bursts with an uneven amplitude pattern. The noise amplitude may be reduced by lowering the burn rate or by structure modifications; however, the low rates cause higher octane requirement. With a stiffer engine structure, higher burn rates can be used without roughness noise, but appreciable gains are not practical because of the weight and cost penalties. A new way to eliminate this noise is proposed. If the amplitudes of the noise bursts from each cylinder are made the same, the roughness noise changes to an acceptable sound. This means that the rate of pressure rise in each cylinder must be the same.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Members save up to 18% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:
TECHNICAL PAPER

Combustion Noise of Two-Stroke Gasoline Engines and its Reduction Techniques

891125

View Details

TECHNICAL PAPER

Improvement of Comfort Aspects for High Efficiency Diesel Engines

2013-26-0119

View Details

TECHNICAL PAPER

Identification of Internal Noise Sources in Diesel Engines

831330

View Details

X