Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
108 words
An ignition system for igniting a spark plug of an internal combustion engine, comprising a transformer (14) which includes a primary winding (16) and a secondary winding (12); coupling means for coupling the secondary winding to the spark plug; energy storage means (C,31) chargeable from a d.c. voltage source; discharge means (S1,S2,36) for discharging energy stored in the energy storage means through the primary winding, thereby to develop a voltage in the secondary winding for initiating an arc at electrodes of the spark plug; and control means (31,S1,S2,36) operative after initiation of the arc for developing an alternating current in the secondary winding adapted to maintain the arc.
Claim 2
Dependent Claim
27 words
An ignition system according to claim 1, comprising a timer (76) adapted to control the time during which an alternating current is produced in the secondary winding.
Claim 3
Dependent Claim
27 words
An ignition system according to claim 1 or 2, wherein the discharge means (S1,S2,36) comprises first and second switching means (S1,S2;P1-P4) connected to the primary winding (16).
Claim 4
Dependent Claim
38 words
An ignition system according to claim 3, wherein the discharge means (S1,S2,36) comprises a switch controller (36) adapted to set the first and second switching means (S1,S2;P1-P4) in an off state for charging the energy storage means (C,31).
Claim 5
Dependent Claim
36 words
An ignition system according to claim 4, wherein the switch controller (36) is adapted to set one of the first and second switching means (S1,S2;P1-P4) in an on state to discharge the energy storage means (C,31).
Claim 6
Dependent Claim
51 words
An ignition system according to claim 4 or 5, wherein the switch controller (36) is adapted to connect the primary winding (16) to a d.c. current source through the first and second switching means (S1,S2) sequentially in cyclic manner so as to develop an alternating current in the secondary winding (12).
Claim 7
Dependent Claim
29 words
An ignition system according to any preceding claim, comprising a current controller (30,31,34,35,S3) adapted to control the magnitude of the alternating current (IS) produced in the secondary winding (12).
Claim 8
Dependent Claim
43 words
An ignition system according to claim 7, wherein the current controller comprises an inductor (31) for use in producing the alternating current in the secondary winding; and third switching means (S3) adapted to connect and disconnect the inductor from said d.c. voltage source.
Claim 9
Dependent Claim
36 words
An ignition system according to claim 8, wherein the current controller comprises a current sensor (48) for sensing the current through the inductor and for controlling the third switching means in response to the sensed current.
Claim 10
Dependent Claim
26 words
An ignition system according to any preceding claim, wherein the primary winding (16) is a centre-tapped primary winding, comprising first and second primary winding portions (16A,16B).
Claim 11
Dependent Claim
29 words
An ignition system according to claim 10, wherein the discharge means (S1,S2) is adapted to discharge the energy storage means (C,31) through one of the primary winding portions (16A,16B).
Claim 12
Dependent Claim
29 words
An ignition system according to claim 10 or 11, wherein the control means (31,S1,S2,36) is adapted to connect the primary winding portions (16A,16B) sequentially to said d.c. voltage source.
Claim 13
Dependent Claim
22 words
An ignition system according to any one of claims 1 to 9, wherein the primary winding (16) is a single primary winding.
Claim 14
Dependent Claim
17 words
An ignition system according to any preceding claim, wherein the energy storage means is a capacitor (C).
Claim 15
Dependent Claim
21 words
An ignition system according to any one of claims 1 to 13, wherein the energy storage means is an inductor (31).