Spark
Ignition Engine Tribological and Friction Research
Abstract:
In an attempt to further understand and reduce engine friction,
several tribological tests are being prepared. One test will
compare the differences between aluminum metal matrix cylinder
liners and stock cast iron liners in a six cylinder spark ignition
engine. The other test will be to determine the effects of a
variety of oils on total engine friction.
Motivation:
Engine friction is the primary difference between the energy input
from the fuel and the energy available at the drive shaft of the
engine. In an era where fuel conservation is becoming increasingly
important, reduction in mechanical friction is an outstanding
way to increase fuel economy without sacrificing performance.
In fact by decreasing friction, you can increase performance by
making more of the fuel’s energy available at the drive
shaft. Also by reducing engine friction, you can reduce the size
of your cooling and oil systems because a large portion of the
frictional losses in an engine appear in the form of heat lost
to the coolant and oil. |
Researchers:
Chandrasekaran Sethu
Alex Knafl
Stani Bohac
Zoran Filipi
Dennis Assanis
Sponsors:
Automotive Research Center (U.S. Army TACOM)
Lubrizol |
Current
Work:
Currently the laboratory is being prepared to run advanced wear
testing for both a baseline engine with cast iron cylinder liners
and an engine which features aluminum metal matrix cylinder
liners (click here for picture
of liners) which contain solid lubricants (graphite and
alumina). The aluminum liners offer a considerable weight reduction
versus standard cast iron liners (approximately 60%). Friction
measurements will be taken over the course of the testing and
wear measurements on the piston, rings, and liners will be made
at the end of testing. The goal is to determine if the aluminum
liners have favorable friction and wear characteristics compared
to the cast iron liners.
Another
set of tests being prepared are for lubrication studies. Similar
lubrication studies were conducted on a diesel engine and were
presented in SAE (Society
of Automotive Engineering) paper 2002-01-2681. The studies
will look at the effects different oil formulations have on
engine friction. The oils
vary in viscosity, base stock chemistry, and friction modifiers.
Future
Work:
Future work includes running the tests currently being prepared
and continuing to work on reducing engine friction through tribological
research. When developed, the instantaneous in-cylinder friction
measurement system will then be leveraged to aid in the work and
be used to help quantify changes in in-cylinder and total engine
friction. |
