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Radio-Frequency-Based Urea Dosing Control for Diesel Engines with Ammonia SCR Catalysts

Title data

Dietrich, Markus ; Steiner, Carsten ; Hagen, Gunter ; Moos, Ralf:
Radio-Frequency-Based Urea Dosing Control for Diesel Engines with Ammonia SCR Catalysts.
In: SAE International Journal of Engines. Vol. 10 (2017) Issue 4 . - pp. 1638-1645.
ISSN 1946- 3936

Official URL: Volltext

Abstract in another language

The radio-frequency (RF) or microwave-based catalyst state determination offers the opportunity to operate an automotive catalyst at its optimal point. This has already been proven for the oxidation state of TWCs, the soot loading state on DPFs/GPFs, and the ammonia storage state of vanadium and zeolite based SCR catalysts. However, the latter has only been demonstrated in laboratory scale with synthetic exhaust using gaseous ammonia.This work presents first results on an engine test bench with a serial-type zeolite-based SCR catalyst, using urea solution and the RF tool to detect the current ammonia loading in real time and to control directly the urea dosing system without any additional sensors. The original catalyst volume was reduced by 50 % to operate deliberately the SCR system under high space velocities and to challenge its function. Stationary conditions and operation points with continuously changing NOx emissions and space velocities were observed. In all tests, high NOx conversion was achieved and the ammonia loading could be detected reproducibly in all states by the RF tool. Furthermore, the RF tool was successfully used with closed-loop control of the urea dosing as a two-point control with and without hysteresis. By varying the controlled ammonia storage window, the operation borders of too high or too low ammonia storage were investigated, and the ideal storage value was found. The performed experiments demonstrate that direct operation on a specific ammonia loading can ensure both maximum NOx conversion and avoid ammonia slip, even with space velocities over 180,000 h-1. Therefore, the control strategy using the RF tool might allow a catalyst volume reduction.

Further data

Item Type: Article in a journal
Refereed: Yes
Institutions of the University: Faculties > Faculty of Engineering Science
Faculties > Faculty of Engineering Science > Chair Functional Materials > Chair Functional Materials - Univ.-Prof. Dr.-Ing. Ralf Moos
Profile Fields > Advanced Fields > Advanced Materials
Research Institutions > Research Centres > Bayreuth Center for Material Science and Engineering - BayMAT
Research Institutions > Research Units > ZET - Zentrum für Energietechnik
Research Institutions > Research Units > BERC - Bayreuth Engine Research Center
Faculties > Faculty of Engineering Science > Chair Functional Materials
Profile Fields
Profile Fields > Advanced Fields
Research Institutions
Research Institutions > Research Centres
Research Institutions > Research Units
Result of work at the UBT: Yes
DDC Subjects: 600 Technology, medicine, applied sciences > 620 Engineering
Date Deposited: 27 Sep 2017 08:04
Last Modified: 17 Oct 2022 12:05