초록 ▼

To provide for electronically controlled spark advance of the ignition instant in a transistorized magneto ignition system, the ignition instant is controlled by a threshold switch responsive to voltage generated by the magneto, the threshold being connected to a timing circuit which includes a resi

To provide for electronically controlled spark advance of the ignition instant in a transistorized magneto ignition system, the ignition instant is controlled by a threshold switch responsive to voltage generated by the magneto, the threshold being connected to a timing circuit which includes a resistance network therein, the resistance value of which is variable with respect to operating speed of the engine. The resistance network includes a R/C timing circuit which, as the speed of the engine increases, presents a respectively smaller resistance value to rapidly recurring signals from the magneto so that, effectively, the resistance value of the timing circuit controlling current flow through the threshold circuit is decreased, causing a shift in the ignition instant, the circuit being arranged to advance the spark with respect to upper dead center (UDC) position of the piston of the engine.

대표청구항 ▼

Internal combustion engine ignition system having a magneto generator (10) having a driven magnetic pole system (11); a primary ignition coil (13a) in flux linking relation to the magnetic system; a secondary coil (13b) inductively coupled to the primary coil (13a) and a spark gap (15) connected to

Internal combustion engine ignition system having a magneto generator (10) having a driven magnetic pole system (11); a primary ignition coil (13a) in flux linking relation to the magnetic system; a secondary coil (13b) inductively coupled to the primary coil (13a) and a spark gap (15) connected to the secondary coil; a semiconductor controlled switch (16) in the primary circuit of the primary ignition coil (13a); a control circuit connected to and controlling said controlled switch (16) to become conductive and store magnetic energy in the primary coil and to open at an ignition instant to cause an inductive voltage to arise at the secondary for generation of a spark at the spark gap to cause an ignition event in the internal combustion engine; said control circuit including a threshold circuit (23, 22, 24, 29) connected in the primary circuit and responsive to a predetermined voltage level therein and, when said voltage level is reached, providing a conduction control signal to the controlled switch (16), and comprising, in accordance with the invention, means to continuously vary the occurrence of the ignition instant (Zzp) as a function of speed of the internal combustion engine (E) including a main timing circuit (23, 24) having a timing capacitor (24) connected in circuit with the threshold circuit (23, 22, 24, 29), said main timing circuit including impedance means having a variable and controllable impedance value; circuit means coupled to the magneto generator and the impedance means to control the impedance value of said impedance means as a function of engine speed; and a semiconductor switch (20) connected to control conduction of said controlled switch (16) and having its control path connected to said timing capacitor and thereby its conduction controlled by the voltage across said timing capacitor (24).