Internal-combustion engines – High tension ignition system – Having a specific ignition coil
Reexamination Certificate
2000-01-12
2001-08-21
Argenbright, Tony M. (Department: 3747)
Internal-combustion engines
High tension ignition system
Having a specific ignition coil
C336S179000, C336S198000
Reexamination Certificate
active
06276348
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an ignition coil assembly, and more particularly to a pencil coil wherein a spool thereof has a ramp provided at each end.
BACKGROUND OF THE INVENTION
Ignition coils for internal combustion engines adapted to be directly coupled to spark plugs are known. For example, see U.S. Pat. Nos. 5,706,792 and 5,736,917, the disclosures of which are hereby incorporated herein by reference. It is known that conventional ignition coils (or pencil coils) utilize both a primary coil and a secondary coil. The primary coil is typically a low voltage coil, while higher voltages are induced in the secondary coil.
Prior art
FIG. 2
illustrates a conventional spool
100
upon which a secondary coil is wrapped or wound. Secondary spool
100
includes a cylindrical mid-section
102
upon which the windings
106
are wrapped. Spool
100
further includes planar flanges
104
extending outwardly at approximately a 90 degree angle from each end of the mid-section.
Unfortunately, the provision of this type of flange
104
at both ends of the spool is problematic. For example, the 90 degree angle or corner
108
defined by the flange and the end of the mid-section wind-on surface may cause a voltage concentration between the secondary and primary windings, at the high voltage end of the secondary winding.
Another problem inherent with flanges
104
at both ends of the spool arises upon thermal expansion. The thermal coefficient of expansion of the spool is typically much higher than that of the wire
106
. There may be relative movement between the flange
104
and the end
110
of the wire segment upon exposure to high temperatures, thereby creating a gap adjacent one or both of flanges
104
. When a flexible encapsulant is used, this gap could allow a collapse of the winding, which could increase stress when the coil returns to a hot condition. The collapse could also increase the wire to wire voltage gradient which may lead to electrical failure.
It is apparent from the above that there exists a need in the art for an ignition coil or pencil coil: having a secondary spool requiring a lessor number of wire turns/wraps; allowing for a reduction of voltage concentration between the secondary winding and the primary spool; and/or for minimizing adverse effects upon separation between the spool and coil upon thermal expansion/contraction.
SUMMARY OF THE INVENTION
Generally speaking, this invention fulfills any or all of the above described needs in the art by providing a pencil coil assembly for providing a spark to a cylinder of an internal combustion engine, the coil assembly comprising:
an outer housing;
a primary coil disposed within said outer housing, said primary coil adapted to be connected to a voltage source;
a secondary coil wound on a spool, said spool including first and second ends; and
wherein a first ramp structure is defined proximate said first end of said spool and a second ramp structure is defined proximate said second end of said spool.
This invention further fulfills any or all of the above described needs in the art by providing an ignition coil assembly for use in conjunction with an engine, the ignition coil assembly comprising:
a spool having a midsection including a coil-receiving surface upon which a coil is wound; and
wherein the spool includes first and second ramp structures at opposite ends thereof upon which the coil is wound.
This invention will now be described with respect to certain embodiments thereof, along with reference to the accompanying illustrations.
REFERENCES:
patent: 5706792 (1998-01-01), Boyer et al.
patent: 5736917 (1998-04-01), Kawano et al.
patent: 5929736 (1999-07-01), Sakamaki et al.
patent: 09246075-A (1997-09-01), None
Bracken Norman H.
Hirudayaraj Antony V.
Moga Viorel
Skinner Albert Anthony
Argenbright Tony M.
Delphi Technologies Inc.
Dobrowitsky Margaret A.
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