| 摘要 |
<p>A method for lambda control operates with two control circuits for different groups of cylinders. Two-point control is operated in each control circuit, causing control oscillation each time. The phase shift between the two oscillations is found and set to a predetermined value. If the predetermined value of the phase shift corresponds to half an oscillation period, the exhaust gas from one group of cylinders changes from rich to lean when the exhaust gas from the other changes from lean to rich, and vice versa. If the two quantities of exhaust gas are mixed upstream of a catalyser, the latter receives a gas mixture with a lambda value of substantially 1. The method thus makes it possible to attain an oscillation amplitude in the exhaust gas lambda value which is smaller than those of the air-fuel mixture fed to both groups of cylinders. The result is the improved conversion of the pollutants. A device for implementing said method has two means of two-point control, one to determine the actual and one to set the target phase shift.</p> |
