Method for controlling the fuel-air ratio for an internal combustion engine

摘要

In the case of a method for controlling the fuel-air ratio for an internal combustion engine with an intake system in which a mixture control unit and a throttle valve are arranged, the exhaust gases of the internal combustion engine flow round an oxygen sensor, which determines the oxygen content of the exhaust gas flow in periodic measurements. Output signals of the oxygen sensor and those of a throttle valve position sensor are fed to a control device influencing the mixture control unit. In order to obtain a lambda displacement as a function of the load range and operating factor, in a first phase the exhaust gases of the internal combustion engine flow round the oxygen sensor and an output signal of the oxygen sensor is fed to the control device, which influences a control element assigned to the mixture control unit so that a stoichiometric mixture where lambda = 1.0 is set. In a second phase the exhaust gases do not flow round the oxygen sensor and the control device functioning in an open control loop triggers the control element by means of a corrected signal as a result of which a stoichiometric mixture adjusted from lambda = 1.0 by a predetermined DELTA lambda is set.