close

Вход

Забыли?

вход по аккаунту

?

Патент USA US3041507

код для вставки
June 26, 1962
3,041,498
A. T. H. FONTAINE
CABLE TERMINAL FOR IGNITION SYSTEMS
Filed Aug. 24, 1960
3 Sheets-Sheet 1
BY
’
I,
/,
v/l,
,
ATT’Y.
June 26, 1962
A. T. H. FONTAINE
3,041,498
CABLE TERMINAL FOR IGNITION SYSTEMS
Filed Aug. 24, 1960
.3 Sheets-Sheet 2
d5
` INVENToR.
AT. H_FUNTAINB.
June 26, 1962
A. T. H. FONTAINE
3,041,498
CABLE TERMINAL FOR IGNITION SYSTEMS
Filed Aug. 24, 1960
5 Sheets-Sheet 3
l.,
li
nu
1
FIG.3.
INVENTOR:
Afl". HFUNTAINE.
BY
ATT’YI
United safes Patent o
3,041,498
er'
ICC
Patented June 26, 1962
2
1
ference suppressor of the type considered in the shape of
'
3,041,498
a plurality of current sections in series relation in an
absorbing sleeve such as to constitute a vrm lilter for in
.
CABLE TERMINAL FOR IGNITION SYSTEMS
Antoine T. H. Fontaine, 12a Dr. Zamenhofstraat,
Rotterdam, Netherlands
'
Filed Aug. 24, 1960, Ser. No. 51,737
Claims priority, application Netherlands Aug. 29, 1959
6 Claims._ (Cl. 315-54)
sertion at a definite point adjacent a spark gap.
A better understanding of the invention will be had
from the detailed description to follow, in connection with
the attached drawing in which
FIGURE l is a viewof the screening of a spark plug
in a first embodiment of a filtering cable terminal ob
This invention relates to filter circuits and particularly
to means for -suppressing high frequency _currents
any 10 tained by building coil sections into a cap for a sparking
plus;
system where they are not desired, onein'stance being an
FIGURE Z is the basic form of the iilter;
ignition system for internal combustion engines for air
FIGURE 3 is a ñlter diagram;
_
FIGURE 4 is a family of curves characteristic for
An object of the invention is to reduce interference to
sensitive measuring or signalling apparatus such as radio 15 the action of the iilter of FIG. 3;
planes, automobiles and the like.
receivers, due to the higher frequency components that
may -be present in any conductors within range of the ap-`
paratus, and speciiically those generated by ignitionsys
tems during the sparking action.
It is well known that the voltage waveY in a spark plug 20
conductor increases rapidly until the spark gap is broken
down and Ilthen decreases rapidly. As this Wave 'is not
FIGURE 5 is an idealized curve taken from this fam
ily;
FIGURE 6 is a diagram illustrative of the action of
the filter of FIG. 3 above the resonance frequency of
FIG. 5;
'
_
FIGURE 7 is a section of a practical suppressor with
shield as shown in FIG. 1; and
.
FIG. 8 is a sectional view taken along line VIII-VIII
sinusoidal but rich in the higher harmonics, these higher
of FIG. 7 with a part broken away.
frequency components generated are picked up by ad
jacent radio receiving apparatus. The harmonics pro 25 The invention initially considers a normal Ímetallic
spark plug cap with extended nozzle as shown in FIG. 1
duce in the receiver unitsv a. sputtering sound sufficient to
and consisting of a shell ,1 fitting closely cna spark plug
seriously interfere withradio reception. '
_
and having a nozzle Z enclosing a pin 3; clamping the
Heretofore suchmethodsas shieldingthe entire en
spark plug conductor or cable C.V
gine or only the ignition system have been tried and these
methods have proved too inconvenient and bulky. Also 30 The spark cable C is connected to the pin 3` by pressing
the cable into the nozzle (see also FIG. 7).
filter systems have been used, these systems necessitating
I have found that the suppressing effect of a normal
special coils and condensers which increase the weight
metal plug cap in itself is quite small, for which reason
of the motor element and the space required per horse
I provide filter sections by replacing the direct connection
power.
The present invention combines the effectiveness of the 35 between the pin 3 and the plug conductor by a coil 5 (see
FIG. 7) made up of sections and having practically no
resistance. The sections all lie within the screening shell
1, with regard to which they present natural capacities,
wiring system.
resulting in the presence in the connection from the cable
In one embodiment the invention provides a cable
termination for ignition systems providing a high degree 40 to the spark gap, of a low-pass ñlter made up of rm
sections.
of protection against the disturbances discussed and com
The basic form of this low-pass filter is shown in FIG
monly occasioned by sparks in the ignition system. The
URES 2 and 3, whereas FIG. 4 `gives an extract from a
frequency region concerned is particularly that about 40
family of curves for these filters showing the region irn
megacycles, being the important region in connection with
radio and television trañic.
45 portant for the present purpose, mainly consisting of
suppression in the region between 40 and 240 megacycles,
It is one object of the invention to construct this cable
though it is also active at higher frequency, at least up to
termination from. coil sections in such a manner as to
800 megacycles, compare FIG. 6 showing the basic
constitute series capacities in the relevant frequency range
form of the same filter at higher frequency.
by inserting the entire coil in a screen of attenuating ma
Moreover the ñlter also has a suppressing action at
terial such as ordinary plain commercial thin plate iron, 50
higher radio frequencies below 40 megacycles.
with respect to which the sections possess partial natural
FIG. 4 shows the attenuation in decibels db as a
capacities resulting in a filter made up of 1r sections
function of the normalized or resonant frequency with
having practically no direct current resistance and func
the quantity m` (i.e. the ratio of series and shunt ca
tioning as connection between the end of the cable and a
conductor terminating in a spark gap as used in ignition 55 pacities) as parameter. The quality Q of a coil section
is supposed to be infinite. In a practical case Q will be
systems.
small resulting in the dotted graph.
It is a feature of the invention to provide the termina
FIG. 5 shows the behaviour of the ñlter.
tion in connection with spark gaps in sparking plugs of
FIG. 7 shows a section of a plug cap according to the
internal combustion engines.
invention
in two mutually orthogonal directions, showing
60
It is another feature of the invention to provide the
at
1
the
lug
shell over a spark plug P, at 2 the nozzle,
termination in connection with spark gaps occurring in a
at 3 the conducting pin protruding from the nozzle 2
distributor of an ignition system.
to contact the cable C core W, at 4 the clamp for grip
The filter is active above its resonance frequency as
ping the plug conductor, at 5 the coil wound on a grooved
a capacitive voltage divider for the suppression of inter~
65 cylinder 6 of refractory insulation and at 7 the insulating
ference.
body in the shell supporting the internal parts and the
It is an object of the invention to suppress interference
coil.
shield and filter methods with substantially no change in
Weight, space and convenience from the ordinary ignition
.5,
from the operation of systems involving spark discharges
by providing a material at a definite point which attenu
It is ya feature that the provision of the subtle means
described at the relevant point in the ignition circuit con~
ates by eddy current losses currents induced by spark 70 stitutes an eiîective suppression by repeated voltage di
discharges in an extensive system.
vision in consecutive sections, each of which in itself only
It is another object of the invention to provide an inter
provides small attenuation.
3,041,498
3
4
ferential grooves therealong each of which contains a coil
It will be understood, of course, that the disclosure
herein has been to a particular means »for carrying out the
invention, but the appended claims are intended to co-ver
such equivalent combinations ‘as the state of the art will
section.
.
3. An element according to clai-m 1 wherein said
grounded metallic sheath is grounded Iby being connected
to the outside of said spark plug.
4. A cable terminal yfor absorbing parasitic frequencies
allow.
What is claimed is:
1. In an- ignition system `for internal combustion en
yfrom spark gaps comprising:
gines having
(a) a sectionalized series coil with low direct current
resistance;
(A) a Spark plus,
l0
(B) a source for energizing said plug,
(C) a conductor between said plug and said source,
(b) a grounded metallic sheath having inherent losses
`surrounding said coil;
Y
`
said coil and sheath constituting, in a range of frequencies
and
(D) an element for `absorbing parasitic frequencies
from the sparks produced ‘by said plug, said element
capacitive voltage divider by reason of the capacitance
being connected between said plug and said conduc
«tor and comprising:
of the coil sections in longitudinal branches and of the
distributed capacitance of the coil sections with respect
to said metallic `surrounding sheath, which `at frequency
`above the resonant frequencies of the coil sections, a
> (l) a series of coil ‘sections with low `direct current
resistance, `and
below resonance acts as yan m-derived low pass iìlter hav
’
(2) a grounded metallic sheath having inherent
losses surrounding said coil,
ing coil sections of low quality.
20
.
'
5. A terminal according to claim 4 in which the natural
resonant frequency of said sectionalized coil lies f-below
`said element constituting:
the lowest frequency of fthe suppression region.
(a) a capacitive voltage divider in a range of inter
6. A terminal according to claim 4 wherein said coil
ference frequencies above the resonant frequency
comprises an insulated cylinder having spaced circumfer- '
of said coil sections, by reason of the capacitance
of said coil sections in axial valignment and of the 25 entially grooves each of which contains a coil section.
distributed capacitance of said coil sections with
References Cited in the file of this patent
respect to said metallic sheath, and
(b) an m-derived low pass ñlter having coil sections
UNITED STATES PATENTS
of low quality at «frequencies below resonance of
30
1,971,497
Miller ______________ __'- Aug. 28, 1934
said element.
2,173,766
Ramsay ______ .__-___'__-_- Sept. 19, 1939
‘2. An element according 4to claim 1 wherein said coil
2,350,367
Peters et al. __________ .__ June 6, 1944
comprises an insulated cylinder having spaced circum
Документ
Категория
Без категории
Просмотров
0
Размер файла
329 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа