Abstract: A method for extracting characterizing features from an ion current trace retrieved from spark plugs of cylinders of an internal combustion engine, comprises the steps of: i. dividing the ion current signal into crank angle subintervals; 5 ii. calculating a measure of ion current in each crank angle subinterval; and iii. Performing a calculation on the measure of ion currents from different subintervals such that the result of the calculation is dimension free. Further it relates to a method of monitoring combustion processes where a plurality of ion current signals from a number of spark plugs (4A, 4B) are 10 retrieved and used in combination.

Abstract: A method for extracting characterizing features from an ion current trace retrieved from spark plugs of cylinders of an internal combustion engine, comprises the steps of: i. dividing the ion current signal into crank angle subintervals; ii. calculating a measure of ion current in each crank angle subinterval; and iii. Performing a calculation on the measure of ion currents from different subintervals such that the result of the calculation is dimension free. Further it relates to a method of monitoring combustion processes where a plurality of ion current signals from a number of spark plugs (4A, 4B) are retrieved and used in combination.

Abstract: A method for extracting characterizing features from an ion current trace retrieved from spark plugs of cylinders of an internal combustion engine, comprises the steps of: i. dividing the ion current signal into crank angle subintervals; ii. calculating a measure of ion current in each crank angle subinterval; and iii. Performing a calculation on the measure of ion currents from different subintervals such that the result of the calculation is dimension free. Further it relates to a method of monitoring combustion processes where a plurality of ion current signals from a number of spark plugs (4A, 4B) are retrieved and used in combination.

Abstract: A method for extracting characterizing features from an ion current trace retrieved from spark plugs of cylinders of an internal combustion engine, comprises the steps of: i. dividing the ion current signal into crank angle subintervals; ii. calculating a measure of ion current in each crank angle subinterval; and iii. Performing a calculation on the measure of ion currents from different subintervals such that the result of the calculation is dimension free. Further it relates to a method of monitoring combustion processes where a plurality of ion current signals from a number of spark plugs (4A, 4B) are retrieved and used in combination.

Abstract: This invention relates to a method for knock detection in a combustion engine, in which combustion is controlled by a control unit (2), which comprises the steps of, a) obtaining at least one sensor signal (4, 4?) carrying information of knock intensity related within a combustion chamber of the combustion engine (1); (b) processing the sensor signal (4, 4?) to obtain a knock intensity related detection variable (z1), (c) using said detection variable (z1) in said control unit (2) arranged to avoid a knocking condition in said combustion engine (1), if the value (z1) of said detection variable indicates knock when compared with a threshold value (T) wherein using two different computations/processes for said processing (5, 6) of the at least one sensor signal (4, 4?) to obtain two separate sub-values (y1, y2), and thereafter combining said sub-values (y1, y2) to obtain said detection variable (z1).

Abstract: This invention relates to a method for knock detection in a combustion engine, in which combustion is controlled by a control unit (2), which comprises the steps of, a) obtaining at least one sensor signal (4, 4?) carrying information of knock intensity related within a combustion chamber of the combustion engine (1); (b) processing the sensor signal (4, 4?) to obtain a knock intensity related detection variable (z1), (c) using said detection variable (z1) in said control unit (2) arranged to avoid a knocking condition in said combustion engine (1), if the value (z1) of said detection variable indicates knock when compared with a threshold value (T) wherein using two different computations/processes for said processing (5, 6) of the at least one sensor signal (4, 4?) to obtain two separate sub-values (y1, y2), and thereafter combining said sub-values (y1, y2) to obtain said detection variable (z1).