Plasma jet ignition system

#The present invention relates to a plasma jet ignition system and more particularly to a plasma jet ignition system for an automotive internal combustion engine.

#In order to extend the lean misfire limit of the conventional spark ignition internal combustion engines, there is a continuing interest in new ignition sources and their effects on engine performance and emissions. Various kinds of new ignition systems have been proposed.

#As shown in FIG. 1, a plasma jet ignition system has been proposed wherein a plasma jet energy storage system is designed as an add-on system, which is used in conjunction with a conventional ignition system which provides the basic spark timing and high voltage trigger signal to the plasma jet ignition plugs.

#FIG. 1 is an interconnection diagram showing a plasma jet ignition system;

#FIG. 2 is a diagram of a four cylinder plasma jet ignition system according to the invention;

#FIG. 3 is an enlarged partial view showing a connection area between a plug cap of an electrical insulator and a steering diode;

#Referring to FIGS. 2 and 3, a preferred embodiment of the present invention will be hereinafter described, wherein like reference numerals which are used in FIG. 1 are to designate like parts shown in FIG. 1 for the simplicity of the description. In FIG. 2, the reference numeral 2 designates an ignition coil; 4 a distributor; the numeral 20 shows a spark energy delivery harness; the numeral 6 refers to a plasma jet energy storage system; the numeral 19 designates a plasma jet energy delivery harness; and the numeral 7 refers to the plasma jet ignition plugs of high tension resistive cables 20, each leading to one of the plasma jet ignition plugs 7 in the conventional manner.

#The plasma jet energy delivery harness includes a plurality of steering diodes 13 arranged to prevent the spark energy from flowing into a storage capacitor 10 (see FIG. 1). Each of the steering diodes 13 has its anode terminal 13a connected to one of the plurality of plasma jet ignition plugs 7 as shown in FIG. 3.

#Referring to FIG. 3, a plug cap 30 of electrically insulating material is integral with an outer sheath 32 of the high tension resistive cable 20. The plug cap 30 includes a metal connector 34 adapted to engage the plasma jet ignition plugs. The steering diode 13 has its anode terminal 13a connected to the metal connector 34. The plug cap 30, although it may have embedded therein the steering diode 13, conceals a connection area where the metal connector 22 is connected to the anode terminal 13a of the steering diode 13.