Method of reducing the Nox content in the exhaust gas of a diesel internal combustion engine

US6209313A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Gerhard Wissler · Geiselhöring, DE
• Gunther Pajonk · Zapfendorf, DE
• Lothar Hofmann · Burgkunstadt, DE
• Manfred Weigl · Viehhausen, DE

Key dates

• Filing date: Nov 9, 1998
• Grant date: Apr 3, 2001
• Expiry date: Nov 9, 2018

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/40
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

Excessive NO.sub.x emission in a diesel internal combustion engine with SCR exhaust gas treatment is detected by a control unit. The excessive NO.sub.x emission value is determined from the catalytic-converter efficiency calculated for the metering of the reducing agent. In response, measures are taken, such as delayed start of the fuel injection, deactivation of a coasting cutoff, reducing an exhaust gas recirculation rate and/or increasing the idling speed. As a result, the NO.sub.x content in the untreated exhaust gas drops, the catalytic-converter temperature increases more quickly after a cold start, and the NO.sub.x emission is reduced.