Method and apparatus for the automatic control of the air ratio of a combustion process

US4032285A · kind A · utility

Assignee

• Brown, Boveri & Cie AG · DE

Inventors

• Franz-Josef Rohr · Weinheim, DE
• Hubert Holick · Lampertheim, DE

Key dates

• Filing date: Dec 19, 1975
• Grant date: Jun 28, 1977
• Expiry date: Dec 19, 1995

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F02B1/04
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

A method for automatically controlling the air ratio of a combustion process by adjustment of the fuel-air mixture as function of the air number, the air number of the exhaust gas being measured with a sensor which is particularly sensitive at an air number of a given magnitude, and the combustion process operating with an air ratio having an air number of a different magnitude out of the sensitivity range of the sensor which includes extracting a hot exhaust gas stream from a combustion process having an air ratio with an air number out of the given sensitivity range of a sensor changing the amount of air in the exhaust gas stream to provide an auxiliary gas stream having an air number in the sensitivity range of the sensor, measuring the air number of the auxiliary gas stream to detect the difference from the air number of the given magnitude, and controlling the air ratio of the combustion process to maintain the air number of the auxiliary gas stream at the given magnitude, and apparatus for carrying out the foregoing method.