TECHNOLOGY
SMALL SEAL CHANGES KEY
TO NEXT-GENERATION DIESELS
Challenges of Tier 4 foster development of new sealing and materials
technologies designed to enhance engine efficiency, emissions performance
While in many cases seemingly a minor player in the overall engine, seals are used in a
number of areas in diesel engines and can play a critical role in improving engine efficiency
and reducing emissions.
BY JOEL JOHNSON
Since the Environmental Pro- tection Agency (EPA) first ini- tiated its regulations to reduce
emissions from diesel engines by
more than 90%, engine manufacturers and their suppliers have worked
diligently to develop and implement
solutions to satisfy the new requirements. Adding to the complexity of
the regulations is the low sulfur fuel
mandate, which is required to avoid
damaging aftertreatment systems.
For engine manufacturers, meeting
the new standards has required a review
of the entire engine, from the fuel management system, to the combustion
process and the post-processing of the
Joel Johnson is vice president of Technol-
ogy, Simrit Division of Freudenberg-NOK,
Plymouth, Mich.
exhaust. Further, it has necessitated a
critical review of all engine components
and technologies, whatever their size or
perceived importance.
This is where seemingly small
sealing components and technologies can make an impact on emissions reductions.
For example, improving the com-
bustion process requires better con-
trol of the fuel management system
and improved sealing of the spent
fuel. Maximizing the efficiency of the
engine calls for more precise engine
timing and improved cylinder sealing
to ensure that the power generated
during the combustion phase is maxi-
mized and used to move the crank-
shaft rather than escaping from the
cylinder. Considering the complexity
of engine timing and the volatility of
the combustion process, this is not an
insignificant challenge.
98 DIESEL PROGRESS NORTH AMERICAN EDITION June 2011
