Other projects:
P-Dependence & Model Construction
Model Reduction and Numerical Toolkit
Adaptive Chemistry for Reacting-Flow Simulations
Developing Next Generation Engine Technologies: Combining
Models and Experiments
J.P. Angelos, W.H. Green, M.A. Singer
Collaboration with W.K. Cheng
Sponsors: Ford Motor Co., BP
Homogeneous charge compression ignition (HCCI) engines have
the potential for high efficiencies and low pollutant emissions.
By comparison with spark ignition (SI) engines, for example,
HCCI engines can yield a 15-20% increase in fuel economy while
emitting lower levels of oxides of nitrogen (NOx).
HCCI engines can also achieve thermal efficiencies comparable
to diesel engines yet maintain near zero levels of
particulate emissions. Despite these advantages, however,
a number of technical issues must
be resolved before HCCI engines become mainstream.
Many of the complications stem from the fact that HCCI engines
are more sensitive to the details of the combustion chemistry
than SI and diesel engines. Hence, without a solid understanding
of the physical and chemical processes taking place in HCCI engines,
it is difficult to develop practical, efficient, and robust engines.
We are developing a fast, full-cycle HCCI engine simulator for
gasoline engines that is fully automated and uses detailed
chemical kinetic mechanisms. The simulator, which we call
MITES (MIT Engine Simulator), is run on a desktop PC and is
capable of using chemistry models that contains over 1000 species
undergoing more than 4000 reactions (e.g., the mechanism for
primary reference fuels). We are using the simulator to characterize
the operating range of HCCI engines and to investigate
the impact of transients (e.g., speed, fueling, valve timing)
on engine performance.
In addition to the modeling and simulation efforts described
above, we also partake in a complementary experimental
program. In close collaboration with colleagues in the Sloan Automotive
Laboratory at MIT, we are using experimental results to validate
MITES and to gain further insight into engine design
and performance characteristics.
By combining experimental and numerical approaches, we seek to
understand and control the physical mechanisms that underlie HCCI
operation. In doing so, we move closer to developing a robust
prototype that demonstrates the feasibility of HCCI engines
in the marketplace.