METHOD FOR IGNITION CONTROL IN COMBUSTION ENGINES

摘要

The invention relates to a method applied in combustion engines having two spark plugs (2/6, 3/7, 4/8, 5/9) in each combustion chamber (40-43), controlling ignition and ionisation current measurements. In order to obtain a stable combustion at high EGR-rates or lean burn a longer spark duration of up to 3 ms is beneficial. The invention enables delivery of sufficient ignition energy for all operating conditions while at the same time being able to detect ionisation within the combustion chamber via the spark plug gap of at least one of the spark plugs in each combustion chamber. This is obtained by having individual ignition voltage supply (14, 22) to two spark plugs, (5) respectively (9), arranged in the combustion chamber (43), where the spark plug (9) acting as a sensor for the ionisation current measurements is operated such that the spark duration is less than 50 % of the other spark plug (5) not acting as a sensor.