tno simcat leaflet · temperature and ammonia coverage ... tno_simcat leaflet.indd 2 07-04-2009...
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SIMCAT is a series of diesel aftertreatment catalyst models developed by TNO’s Business Unit Automotive. In order to ensure good compatibility of results between the real catalysts and the models, the models are fitted using engine testbench data with a dedicated tool that minimises the time required to fit and validate the models. The accurate simulation models reduce the amount of real testing for developing, calibrating and testing the aftertreatment system and its control strategy. SIMCAT provides the automotive industry with a cost-effective solution for designing cleaner diesel emission systems, complying with new and stringent emission standards for diesel-fuelled cars and heavy-duty vehicles.
SIMCATDesigning emission solutions for a cleaner planet
SCR systems use urea as a reducing agent to
effectively eliminate nitrogen oxides (NOx)
from diesel exhaust gases. Optimising the
SCR is a complex task, as is the development
of a DPF regeneration strategy. SIMCAT is a
library of a DOC (Diesel Oxidation Catalyst),
DPF (Diesel Particulate Filter), SCR (Selective
Catalytic Reduction) and SCO (Selective
Catalytic Oxidation) catalyst models (see
figure SIMCAT catalyst model library).
SIMCAT eases the process of developing
(integrated) exhaust aftertreatment systems
by providing realistic simulations of the cata-
lysts steady state and dynamic behaviour.
SIMCAT model, technical details• SCR catalyst model
The SCR is a phenomenological model. It
describes the different physical and chemical
processes that take place inside the catalyst
rather than using catalyst performance
maps. The one-dimensional channel
representation of the catalyst is discretised
over the catalyst length. Gas concentrations,
temperature and ammonia coverage
distributions over the catalyst length can be
analysed. The model can be used for OBD and
control developments for SCR as well as for
dimensioning the catalyst.
TNO_SIMCAT leaflet.indd 2 07-04-2009 15:36:03
TNO Science and IndustryBusiness Unit AutomotivePowertrainsPostbus 7565700 AT HelmondThe Netherlands
Edwin van den EijndenT +31 15 269 73 29F +31 40 265 26 [email protected]
tno.nl
Contact
• DOC and SCO models
The DOC and SCO models are also phenome-
nological, one-dimensional models.
The DOC model describes the process of NO
and HC oxidation. The SCO model represents
a Pt-based slipcat that converts possible NH3
slip from an SCR catalyst. The DOC model can
be used for optimising passive and active
regeneration strategies of the DPF. The effect
of DOC and SCO on the SCR catalyst efficiency
can also be studied.
• DPF model
The DPF model represents a wall-flow filter
and calculates the soot quantity, flow,
pressure and temperature distributions over
the (discretised) filter length during loading
and regeneration. The “filtration” part of the
model represents both the deep-bed and
the cake filtering phases. A version of the
DPF model with a catalytic Pt coating is also
available. These DPF models can be used
to develop regeneration strategies as well
as perform dimensioning and optimisation
studies.
Integrated aftertreatment simulationThe SIMCAT models can be used in the
ADVANCE modelling and simulation environ-
ment and can be connected to the DYNAMO
mean-value engine model. ADVANCE is a
MATLAB/Simulink® environment developed
by TNO’s Business Unit Automotive.
It provides an open, intuitive environment
for modelling and control development.
Model fit toolsEach of the models is validated based on
testbench results obtained from engine and
aftertreatment systems. In order to have a
good model representation of the catalyst,
the model parameters must be fitted accor-
ding to a specific coating/substrate/ageing
stage of the catalyst. For this purpose a test
sequence has been developed to characterise
the steady state and transient behaviour of
the catalysts. For DOC, DPF, SCR and SCO
dedicated fit tools have been developed.
A figure of the SCR fit tool is shown on this
page. These fit tools reduce the time to fit
the models to engine testbench data to
around two days for each catalyst.
SIMCAT simulation applications
• Feasibility emission targets for a certain
cycle
• Study of required catalyst configuration:
particulate Filter/Oxicat/SCR/clean-up
catalyst
• Dimensioning catalyst
• Control development (open and closed
loop)
• Reduce calibration effort on test bench
SIMCAT real-time applications
• Hardware In the Loop
• State estimator: NH3 storage, NOx and
NH3 SCR out (controller)
• Advanced control algorithms
SIMCAT catalyst model library
Fit tool user-interface
DOCmodel
DPFmodel
SCRmodel
SCOmodel
TNO_SIMCAT leaflet.indd 1 07-04-2009 15:35:58