Method and device for determining the ion flow in internal combustion engines

An arrangement for processing an ion flow signal of an internal combustion engine, the arrangement comprising:

• means for selecting a cylinder of said engine for ion flow measurement and forming an ion flow signal;
• means for forming an offset value for said cylinder and subtracting said offset value from said ion flow signal;
• and,
• means for masking the ignition spark and masking the switchover of the cylinder which took place previously for making an ion flow measurement and an offset correction with a previously fixed constant value.

A method for processing the ion flow signal of an internal combustion engine by offset correction, masking and multiplexing for engine control functions, the method comprising the steps of:

• measuring the ion flow signal in each cylinder during an ignition operation to provide a measuring signal;
• then detecting the level value of the measurement signal of the cylinder for the purpose of offset correction;
• deriving a second signal from said measurement signal;
• during said masking, substituting said measurement signal in said second signal by said level value and subtracting said measurement signal from said second signal until the next ignition operation;
• and,
• then combining the channels to be multiplexed into a third signal by adding the second signals of said cylinders.

An arrangement for processing the ion flow signal of an internal combustion engine by offset correction, masking and multiplexing for engine control functions, the arrangement comprising:

• measuring means for measuring the ion flow signal in each cylinder during an ignition operation to provide a measuring signal;
• detecting means for detecting the level value of the measurement signal of the cylinder for the purpose of offset correction;
• means for deriving a second signal from said measurement signal;
• means for substituting said measurement signal in said second signal by said level value and subtracting said measurement signal from said second signal until the next ignition operation;
• and,
• means for combining the channels to be multiplexed into a third signal by adding the second signals of said cylinders.