This paper builds upon recent publication (SAE Technical Paper
2011-01-1388, 2011, doi:10.4271/2011-01-1388) and outlines the
on-going development of an advanced simulator for virtual engine
mapping and optimization of engine performance, combustion and
emissions characteristics.
The model is further advanced through development of new
sub-models for turbulent mixing, multiple injection events,
variable injection pressures, engine breathing and gas exchange, as
well as particulates formation and oxidation. The result is a
simulator which offers engine design and performance data typically
associated with 1D thermodynamic engine cycle simulations but with
the "physics-based" model robustness usually associated
with 3D CFD methods. This combination then enables efficient
optimization of engine design with respect to engine performance,
combustion characteristics and exhaust gas emissions.
As a demonstration, a detailed method to parameterize
(calibrate) the advanced PDF-based model is presented followed by
application to three case studies: 1) a concept study of a
heavy-duty diesel engine, examining the impact of increased
injection pressure and lower compression ratio to meet engine
design constraints and Stage IV/Tier 4 exhaust gas emission limits
for both NOx and PM, 2) examining the performance of
both the proposed model and 3D-CFD to simulate heat release and
exhaust gas emissions in a HSDI diesel engine, 3) performance of
the model over a full load-speed map in terms of combustion and
NOx emissions. The results demonstrate the robustness of
the model compared to experimental observations and equivalent
performance compared to more human resource and CPU cost-intensive
3D-CFD simulations.