| 摘要 |
Electrical apparatus is disclosed for initiating and controlling combustion in free piston engines having a power piston freely reciprocating within a power cylinder of the engine and alternately expanding and compressing gases in a combustion chamber within the power cylinder. A velocity probe in the form of a magnet arranged to move with the power piston and a sensing coil fixed to the housing of the free piston engine provides an electrical signal indicating the instantaneous value of the velocity of the power piston of the free piston engine. This electrical signal from the velocity probe is applied to a Schmitt trigger through a suitable electrical connection such as a voltage divider network or preferably a resistor-capacitor and diode network, and the Schmitt trigger provides an electrical timing signal to conventional means for initiating successive combustion power strokes within the engine. Using the electrical apparatus of the present invention, combustion is initiated for each power stroke at a point in time related to the velocity of the power piston, and thus to the time at which the power piston reverses direction, without the necessity of regard to the physical position, i.e., linear location, of the power piston along its path of movement within the power cylinder. Specifically, the Schmitt trigger is set in one condition when the piston velocity increases to a predetermined level as the piston accelerates during the first part of its movement toward a firing position. Then, as the piston slows down while approaching its reversal for the start of the power stroke, the decrease in piston velocity to a predetermined level sets the Schmitt trigger in another condition to cause a spark igniting another combustion initiating action. Additional electrical circuitry is included which may be used to aid in starting free piston engines.
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