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The Effect of Secondary Fuel Injection on the Performance and Exhaust Emissions of An Open-Chamber Diesel Engine
Sector:
Language:
English
Abstract
Secondary injection in a diesel engine is defined as the
introduction of additional fuel into the combustion chamber after
the end of the main injection. It is usually caused by residual
pressure waves in the high-pressure pipe line connecting the pump
and injector. When these waves exceed the injector opening
pressure, secondary injection occurs.
Tests revealed that the U.S. Army TACOM single-cylinder engine
used in this investigation, fitted with an American Bosch injection
system, had secondary injection within the normal engine operating
region.
The pump spill ports and delivery valve were redesigned to
eliminate secondary injection, in accordance with previously
reported work. Comparative tests of both the conventional and
modified injection systems were run on the same engine, and the
effects of secondary injection on engine power, economy, and
exhaust emissions were determined. The results indicate that
secondary injection increased smoke, unburned hydrocarbons, and
specific fuel consumption. Power was reduced.