Patent ID: 6505500
Filing Date: 2003-01-14
Classification: F02D

Abstract:
An arrangement for detecting ionization in a combustion chamber of a combustion motor in which fuel self-ignites by means of compression, comprising:a piston that moves within a cylinder; an open-chamber combustion chamber delimited by a cylinder roof, cylinder walls and an upper surface of the piston; a recess provided in the upper surface of the piston, into which recess the fuel is injected for self-ignition and combustion; and a measurement device having an electrically conductive member that has an outer end forming a connection portion for electrical contact to external measurement equipment and an inner end exposed within the combustion chamber and forming a measurement tip detecting ionization in the combustion chamber, the measurement tip extending into the combustion chamber through the cylinder roof and down into the recess of the piston, the measurement tip terminating substantially centrally within the combustion chamber; in which the distance between an innermost end of the measurement tip and the cylinder roof, when the piston is in an upper dead-point position within the cylinder, is at least 40% of the distance between the cylinder roof and the piston measured perpendicularly from a plane of the cylinder roof to a center of the recess.