Engine with flow coupled spark discharge

Method of maintaining a cyclic, spark ignited combustion, comprising the steps of:

• (a) cyclically flowing an air-fuel mixture of high dilution along a selected traversing dimension of a combustion zone, (b) creating a high power spark discharge of arc discharge type in the air-fuel mixture flow to create a directed flame front kernel therein, and (c) maintaining the flow and discharge conditions such that, within most discharge firing cycles, the directed flame front kernel traverses at least 1/3 of said selected length, the discharge power being at least 100 watts, its duration at least 100 usecs, and its energy at least 20 mj whereby each discharge couples to the flow and takes on a form elongating downstream without spark segmentation for a majority of the discharge duration.

Apparatus for maintaining a cyclic, spark ignited combustion, comprising:

• (a) means defining a combustion zone;
• (b) means for cyclically flowing an air-fuel mixture along a selected traversing dimension of said combustion zone, (c) means for creating a high power spark discharge of arc discharge type in the air-fuel mixture flow to create a time front kernel therein, and (d) means for maintaining the flow and discharge conditions such that, within most discharge firing cycles, the flame front kernel traverses at least 1/3 the said selected length, the spark discharge power is in excess of 100 watts, the discharge duration is at least 100 microseconds, and the discharge provides at least 20 millijoules of spark discharge energy to the mixture, whereby each spark discharge couples to the flow which takes on a form of stretch-elongation downstream moving downstream in the flow without segmentation or break-up for a majority of the discharge duration.

In an internal combustion, IC, engine including means for forming at least one combustion chamber, means for forming an air-fuel mixture therein, means for cyclically igniting said mixture, the latter means including at least one igniter element in contact with the chamber's air fuel mixture contents and means for energizing said igniter element to produce a mixture igniting spark discharge at the spark firing end of said igniter element, the improvement comprising:

• means for producing bulk flow of the air-fuel mixture at the spark firing end of said igniter element during the time of ignition for most normal operating conditions of the engine such that the mixture is ignited by the spark discharge, and for moving the spark discharge and the initial flame formed from said spark discharge in a direction toward a central region of said combustion chamber in part as a result of said mixture flow, and wherein motion of said spark discharge is achieved at least, in part, by elongation or stretching of said spark discharge without break up or segmenting of the main spark energy delivery portion of said spark discharge.