The catalytic converter can only work correctly if the air quantity indicator X (lambda) as close as possible to 1, which corresponds to the ratio of fuel and air in the combustible mixture of 14.7:1. To achieve this, the ignition system is equipped with a so-called lambda control. In this case, the lambda probe measures the oxygen content in the exhaust gases, this is a comparative value for determining the composition of the air-fuel mixture. If the measured value differs from the ideal value, the control unit adjusts it. The regulation operates in the X range from 0.8 to 1.2, while fluctuations are quite desirable, because only in this case can the catalytic converter carry out an almost complete conversion of harmful substances.
A traditional lambda probe gives a usable signal only at temperatures above 350°C. In order to reach this temperature more quickly, the probe in 16V 1.6L engines is mounted forward in the exhaust manifold. In engines 16V 1.8 and 2.0 l, the lambda probe is located in front of the exhaust pipe and is additionally heated electrically. Until the operating temperature is reached, the system is not regulated and is guided by a given average value X.
Visitor comments