Method and apparatus for igniting a combustible mixture, especially gasoline-air in the combustion chamber of an internal combustion engine

Claim 1

In an internal combustion engine (11), apparatus for igniting a combustible fuel-air mixture within the combustion space (12, 21) of the cylinder of the combustion engine (11), a sparkplug (18) having spark electrodes located in the combustion space (12, 21); ignition spark generating apparatus (17, 26; 25, 27) coupled to the sparkplug; and means to enhance energy output from the sparkplug for ignition during the breakdown phase of sparking of the sparkplug comprising means (5) for sensing air quantity being supplied to the engine and for providing an air quantity signal (A); means (6) for sensing fuel quantity being supplied to the engine and for providing a fuel quantity signal (F); a control unit controlling the number of breakdowns of spark flash-overs across electrodes of the sparkplug as a function of the output representative of the ratio of fuel to air; an actual combustion sensor (21) sensing the course of combustion of the fuel-air mixture within the combustion space (12, 21) and providing an actual combustion output signal; the control unit (16, 7; 22) including a memory (7, 23) connected to receive the fuel signal (F) and the air signal (A), relating fuel quantity and air quantity and providing an output representative of the ratio of fuel to air, said control unit (22) further including a memory-and-comparator unit (23), forming part of said memory (7) and a function storage-and-controller unit (24), the actual combustion signals being applied to the memory-and-comparator unit (23) for comparison with stored values therein, representative of ideal combustion, and providing a control signal to the function store-and-controller unit (24) upon deviation of the course of combustion, as sensed by the combustion sensor (21) from the stored values in the memory-and-comparator unit, the function store-and-controller unit providing an output signal representative of the number of sparking pulses to be applied to the spark electrodes of the spark plug, and a multiple spark generating unit (26, 27) connected to and controlled by the function store-and-controller unit (24) of the control unit (22) providing an output signal representative of the number of sparking pulses to be applied to the spark electrodes of the spark plug to provide optimum ignition of the combustible mixture under the then pertaining operating conditions of the engine.