Exhaust-Aftertreatment Integrated, DoE-based Calibration FEV GmbH

Format:

Conference/Event

Author/Creator:

Rosefort, Rosefort, author.

Contributor:

Kwee, Henry

Pischinger, Stefan

Wiartalla, Andreas

Conference Name:

SAE 2012 World Congress & Exhibition (2012-04-24 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2012

Summary:

For on- and off-highway applications in 2012/2014 newlegislative emissions requirements will be applied for bothEuropean (EURO 6/stage 4) and US (US 2010/Tier4 final) standards.Specifically the NOX-emission limit will be lowered down to 0.46g/kWh (net power 56 kW (EU)/130 kW (US) - 560 kW). While for theprevious emissions legislation various ways could be used to staywithin the emissions limits (engine internal and aftertreatmentmeasures), DeNOX-aftertreatment systems will be mandatory toreach future limits.In these kinds of applications fuel consumption of the enginesis a very decisive selling argument for customers. Total cost ofownership needs to be as low as possible. The trade-off betweenfuel consumption and NOX emissions forces manufacturers to findan optimal solution, especially with regard to increasing fuelprices.In state-of-the-art calibration processes the aftertreatmentsystem is considered separately from the calibration of thethermodynamics. The thermodynamic engineers find the best fuelconsumption in steady state engine operating points and mostefficient combustion with regard to engine-out emissions whichmight be converted by an aftertreatment system with an assumedconversion rate.The problem associated with this approach is that the transientand therefore the heat-up behavior of the aftertreatment system arenot being considered. The heat-up behavior becomes more and moreimportant in particular for test procedures including acold-started cycle such as WHTC or NRTC. To overcome these problemsa second mode for the heating of the exhaust aftertreatment system(EATS) and sometimes a third mode with low NOX emissions will becalibrated separately. The optimization of the operation strategywith all modes is mostly done at the test bench. The optimizationis always done in a serial way when using this approach. This doesnot consider all calibration parameters at the same time.Therefore, the overall fuel consumption or the total cost ofownership does not reach the optimum.A new approach developed by FEV GmbH and the Institute forCombustion Engines RWTH Aachen University (VKA) takes into accountthe aftertreatment system and all engine calibration parametersfrom the first calibration step. VKA and FEV have developed a tool(SimEx) which is capable of simulating a freely configurableaftertreatment system. The integrated global engine DoE and anautomatic optimizer will calibrate all engine and EATS parameters.The target of the optimization is an optimal solution for fuelconsumption/total cost of ownership with regard to the transienttail-pipe emissions. The engineering target for the emissions inthe homologation cycle is typically the constraint. Along with thereduction of fuel consumption in the certification cycles the fuelconsumption of the specific application can also be taken intoaccount during the calibration process through the use ofcustomer-defined cycles. The total cost of ownership can beeffectively minimized through this process.The parameters for optimization can be chosen completely freely,e.g., injection and air path parameters for different engine modes,operation strategy, EATS parameters like size and position.Furthermore different models can be included, such as ECU modelsfor the operation strategy, catalyst-aging models, and newlyconfigured ones.If use of the tool is begun in a state where the exhaustaftertreatment is not fixed, there is the opportunity to design andoptimize the aftertreatment system for the lowest total cost ofownership including the prices for precious metal and consumed fuelover lifetime.Overall, this tool allows the integrated optimization of thewhole calibration process instead of calibrations based onindividually optimized parts

Notes:

Vendor supplied data

Publisher Number:

2012-01-1303

Access Restriction:

Restricted for use by site license