Method and arrangement for controlling the quantity of fuel for an internal combustion engine having a catalytic converter

A method for controlling the fuel quantity for an internal combustion engine having a catalytic converter, the method comprising the steps of:

• determining the air mass flow inducted by the engine;
• determining a precontrol variable for the quantity of fuel in dependence on current values of operating variables of the engine;
• presetting a desired lambda value for the air/fuel mixture to be supplied to the engine;
• checking the actual lambda value of the exhaust gas forward of the catalytic converter;
• comparing the desired lambda value to the actual lambda value to form a comparison;
• controlling the fuel quantity in dependence upon said comparison;
• determining the oxygen actual charge level of the catalytic converter;
• comparing the determined actual charge level to a desired charge level;
• then, when the actual charge level is greater than the desired charge level, lowering the desired lambda value to below the value one;
• otherwise,
• when the actual charge level is less than the desired charge level, increasing the desired lambda value above the value one;
• determining the actual charge level from the maximum storable oxygen quantity and the current stored oxygen quantity with the current stored oxygen quantity being determined as a time integral of the product of:
• the air mass flow supplied to the engine and the actual lambda value.

An arrangement for controlling fuel quantity for an internal combustion engine having a catalytic converter, the arrangement comprising:

• an air flow detector for detecting the air mass flow inducted by the engine;
• means for determining a precontrol variable for the quantity of fuel in dependence upon current values of the operating variables of the engine;
• means for presetting a desired lambda value for the air/fuel mixture to be supplied to the engine;
• a lambda probe disposed forward of the catalytic converter for checking the actual lambda value of the exhaust gas of the engine;
• comparison means for comparing said desired and actual lambda values to obtain a comparison;
• a lambda controller for controlling the fuel quantity in dependence upon said comparison between said desired lambda value and said actual lambda value;
• means for determining the oxygen actual charge level of the catalytic converter;
• and,
• means for changing said desired value for the lambda control in dependence upon a comparison between the actual and desired charge levels of the catalytic converter in such a manner that, when the actual charge level is greater than the desired charge level, the desired lambda value is lowered to below the value one;
• otherwise, when the actual charge level drops below the desired charge level, the desired lambda value is increased above the value one.

A method for controlling the fuel quantity for an internal combustion engine having a catalytic converter and having a lambda controller with a switching threshold, the method comprising the steps of:

• determining the air mass flow inducted by the engine;
• determining a precontrol variable for the quantity of fuel in dependence on current values of operating variables of the engine;
• presetting a desired lambda value for the air/fuel mixture to be supplied to the engine;
• checking the actual lambda value of the exhaust gas forward of the catalytic converter;
• comparing the desired lambda value to the actual lambda value to form a comparison;
• controlling the fuel quantity in dependence upon said comparison;
• determining the oxygen actual charge level of the catalytic converter;
• comparing the determined actual charge level to a desired charge level;
• and,
• then, when the actual charge level is greater than the desired charge level, changing the switching threshold in a first direction;
• otherwise,
• when the actual charge level is less than the desired charge level, changing the switching threshold in a second direction opposite said first direction.

A method for controlling the fuel quantity for an internal combustion engine having a catalytic converter, the method comprising the steps of:

• determining the air mass flow inducted by the engine;
• determining a precontrol variable for the quantity of fuel in dependence on current values of operating variables of the engine;
• presetting a desired lambda value for the air/fuel mixture to be supplied to the engine;
• checking the actual lambda value of the exhaust gas forward of the catalytic converter;
• comparing the desired lambda value to the actual lambda value to form a comparison;
• controlling the fuel quantity in dependence upon said comparison;
• determining the oxygen actual charge level of the catalytic converter;
• comparing the determined actual charge level to a desired charge level;
• and,
• then, when the actual charge level is greater than the desired charge level, changing the amplitude of P-jumps in a first direction;
• otherwise,
• when the actual charge level is less than the desired charge level, changing the amplitude of P-jumps in a second direction opposite to said first direction.

A method for controlling the fuel quantity for an internal combustion engine having a catalytic converter, the method comprising the steps of:

• determining the air mass flow inducted by the engine;
• determining a precontrol variable for the quantity of fuel in dependence on current values of operating variables of the engine;
• presetting a desired lambda value for the air/fuel mixture to be supplied to the engine;
• checking the actual lambda value of the exhaust gas forward of the catalytic converter;
• comparing the desired lambda value to the actual lambda value to form a comparison;
• controlling the fuel quantity in dependence upon said comparison;
• determining the oxygen actual charge level of the catalytic converter;
• comparing the determined actual charge level to a desired charge level;
• and,
• then, when the actual charge level is greater than the desired charge level, changing integration speeds and integration times in a first direction;
• otherwise,
• when the actual charge level is less than the desired charge level, changing integration speeds and integration times in a second direction opposite to said first direction.