 Presented
by Hans Musielik for the Research Communications Studio
University
of South Carolina October 3, 2002
Department of Mechanical Engineering
300 Main Street, Room A016
Columbia,
29208
Foreword: Camless Engine
In our ongoing research
at the University of South Carolina we are developing a camless
engine in order to improve power, increase efficiency and reduce
emissions. We are experimenting with a Piezoelectric Piloted Hydraulic
Valve Actuator (PZT). Piezoelectric controller devices feed back
extremely quick response rates at very high frequencies.
In a conventional
internal combustion engine ICE
the valves are manipulated by a camshaft, which is hooked mechanically
to a crankshaft by a belt or chain. There is a direct relation
between the valve operation and the rpm-speed, while neglecting
the load and other operating parameters of the engine at a given
time. Therefore, on the design of today’s motors, engineers compromise
conflicting requirements for various operation conditions.
What is our Camless
Engine Research
By
developing a system in which the valves can be operated individually
as dictated by the engine and other conditions, we can optimize
tradeoffs between 1) engine performance 2) fuel efficiency 3)
reduced emissions and 4) idle stability
The best way to get optimized results is to equip the engine with
a variable valve actuation (VVA). The closest approach so far
has been with electronic solenoids.
However, researchers have had problems controlling a solenoid
through a range of motions rather than just their two extremes.
Figure 1: Picture of the current camless engine
prototype (Photo
courtesy of AARG at USC)
At the University of South Carolina, our research team is giving
the VVA a different approach by replacing solenoids with piezoelectric
stacks. The range of operation of piezoelectric controlled
devices depends only on the power applied to the stacks. Hydraulic
and mechanical devices can later amplify any displacement.
About Patents
Another important aspect of the research is establishing and understanding
the already existing technologies by searching through national
and international patents as well as looking into worlwide research
projects at universities and in the industrial market. Due to
the international nature, some patents or research reports are
written in a different language than English and translation presents
a major obstacle. Careful translations require specific technical
engineering language skills and good general engineering knowledge
to understand the system being analyzed. At the moment these tasks
are my responsibility.
Searches through
various patents involving camless engines using piezoelectric
technology have returned interesting results. I have not found
a specific patent that directly applies to our research here at
the University of South Carolina; however, some companies appear
to have developed individual parts that are very similar if not
identical in nature to ours. A more careful study of these patents
is now required, not only to see if we can learn something from
them but also to avoid legal issues regarding intellectual rights
and copyright
laws.
Patent searches
are not only important for legal aspects but also for statistical
analysis. If we study and compare a particular category of patents
over a given period of time, we can most likely identify various
trends, which could explain their cause and effect.
International Patents trends on
VVA ‘s including Camless Engines
The above graph shows a
steady increase in Camless engine patent applications in the early
90’s, while there was not too much going on throughout the 70’s
and most of the 80’s. A likely cause for this trend is a more
stabilized economy during the 80’s and a leaping step in software,
hardware and computing technology during the late 80’s and 90’s.
These advances in computer technology allow for faster calculations
by the Engine Control Unit (ECU) therefore controlling more precisely
and effectively the high-speed valve actuators. Advances in material
research and development have surely had their share of importance.
dSPACE
Another aspect of
my research is the study, understanding and implementation of
dSPACE. dSPACE is combination of hardware and software that allows
us to create virtual simulations of the developed engine. Having
dSPACE optimizes the development processes
with real-time systems for rapid control prototyping,
production code generation, and hardware-in-the-loop tests.
Want some more links?
Please point any on any of the below websites
and a brief description will pop up.
http://www.dspace.com/
http://www.bmw.com/
http://www.bmw.de/
http://www.uspto.gov/
http://www.dpma.de/
http://www.sc.edu/
http://www.me.sc.edu/
http://www.me.sc.edu/research/AARG
http://dict.tu-chemnitz.de/
http://www.piezo-kinetics.com/tutorial.htm
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