Impacts on the Emissions Monitoring System (OBD) Due to the Use of Biodiesel and Higher NOx...

Post on 07-May-2015

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This paper analyses the operation of the SCR aftertreatment system when using conventional diesel and biodiesel, to explore the characteristics of the NOx sensor and to analyze its behavior of NOx detection in real applications with the engine using biodiesel.

Transcript of Impacts on the Emissions Monitoring System (OBD) Due to the Use of Biodiesel and Higher NOx...

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Impacts On The Emissions Monitoring

System

(OBD) Due To The Use Of Biodiesel And

Higher Nox

Emissions

Leonardo de Oliveira Costa

IAV do Brasil

Rodrigo Silva Santos

IAV do Brasil

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- INTRODUCTION TO OBD

• To achieve the new emission standards (PROCONVE P7 2012), it will be needed

to control and monitoring (OBD) of exhaust gas emissions (NOx and PM);

• For engines with SCR as exhaust gas treatment technology, it will be mandatory

monitoring of exhaust gas emissions using a NOx sensor in the exhaust pipe;

• When above OBD emissions tolerances for NOx emissions, the ECU must actuate

in the engine and advise the driver;

- RENEWABLE FUELS

• The automotive industry is always looking for renewable fuels to reduce the

dependency on petroleum. Nowadays the biodiesel is the renewable fuel to replace

the diesel;

• The biodiesel has benefits about reduction of major components on the emissions

gases, ONLY increase on the NOx emissions;

• The brazilian government has a plan to increase the amount of biodiesel in the

common diesel in some years;

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- OBJECTIVE OF THE PROJECT

• Analysis the increase of NOx emissions when the engine is fueled by biodiesel

(B100) to study the influence on OBD thresholds and diagnosis.

- Tested Engine

7 liters, 6 Cylinder in Line, 4 Valves, 300HP @ 2400rpm, common-rail, EURO V

with SCR

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Global Value = 1,97g/kWh

Diesel

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Global Value = 2,6g/kWh (Increase of 32%)

B100

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Maximum increase of 80,8%

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• SCR System Overview

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• Diesel

• 1 NOx Sensor Downstream + Sensor Model Upstream

•Open Loop Dosing Control

400 ppm1000 ppm

ηηηη= 60% > 30%

Ok!

System Design 1

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• B100

• 1 NOx Sensor Downstream + Sensor Model Upstream

•Open Loop Dosing Control

720 ppm1000 ppm

ηηηη= 28% < 30%

Not Ok!

System Design 1

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• Diesel

• 1 NOx Sensor Downstream + 1 NOx Sensor Upstream

400 ppm1000 ppm

ηηηη= 60% > 30%

Ok!

System Design 2

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• B100

• 1 NOx Sensor Downstream + 1 NOx Sensor Upstream

720 ppm1800 ppm

ηηηη= 60% > 30%

Ok!

System Design 2

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• Diesel

• 1 NOx Sensor Downstream + Sensor Model Upstream

•Close Loop Dosing Control

400 ppm1000 ppm

ηηηη= 60% > 30%

Ok!

System Design 3

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• B100

• 1 NOx Sensor Downstream + Sensor Model Upstream

•Close Loop Dosing Control

720 ppm1000 ppm

ηηηη= 28% < 30%

Not Ok!

System Design 3

400 ppm

ηηηη= 60% > 30%

Ok!

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- Conclusion

• Biodiesel has a direct impact on NOx emissions value;

• and also on OBD threshold values and detection;

• on SCR System Design with only one NOx sensor, at least a close loop control

should be consider and also a low efficiency during normal Diesel operation to

make possible a efficiency increase during Biodiesel operation;

• Also a NOx sensor upstream the catalyst can be used to avoid wrong efficiency

detection and also to detect the use of Biodiesel

• Further research should be done with SCR System Design and also Biodiesel

Sensor.

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Thank you!

Leonardo de Oliveira Costa

leonardo.costa@iav.de

Rodrigo Silva Santos

rodrigo.silvasantos@iav.de