Internal-combustion engines – High tension ignition system
Reexamination Certificate
2002-11-07
2004-04-13
Kwon, John (Department: 3747)
Internal-combustion engines
High tension ignition system
C123S14300R, C123S634000, C336S096000
Reexamination Certificate
active
06718958
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ignition apparatus for an internal combustion engine which supplies a high voltage to a spark plug for each engine cylinder.
2. Description of the Related Art
FIG. 7
is a plan view of an ignition apparatus
1
for an internal combustion engine shown in Japanese Patent Laid-Open No. Hei 7-29751.
FIG. 8
is a cross sectional view of the ignition apparatus
1
for an internal combustion engine taken along line VIII—VIII in FIG.
7
.
FIG. 9
is a plan view of a wiring module
9
shown in FIG.
9
.
FIG. 10
is a view of the wiring module
9
when seen from arrow A in FIG.
9
.
FIG. 11
is an electric circuit diagram of the ignition apparatus
1
for an internal combustion engine shown in FIG.
7
.
The ignition apparatus
1
illustrated is used by a simultaneous ignition system for an internal combustion engine, that is, the opposite ends of a secondary coil
6
of each transformer are connected with two spark plugs. The ignition apparatus
1
is provided with three transformers
1
A,
1
B,
1
C, and is used for an internal combustion engine having six cylinders.
The first through third transformers
1
A,
1
B,
1
C of the ignition apparatus
1
are built into a casing
8
that is molded with a resin and has a plurality of high-voltage towers
8
a
formed at its head. Each of the first through third transformers
1
A,
1
B,
1
C includes a closed magnetic circuit core
2
which forms a hollow-rectangular-shaped closed magnetic circuit, a primary coil
4
which has a conducting wire wound around a primary bobbin
3
surrounding the closed magnetic circuit core
2
, and a secondary coil
6
which has a conducting wire wound around a secondary bobbin
5
surrounding the primary coil
4
. The first through third transformers
1
A,
1
B,
1
C are fixed to the casing
8
through a resin portion
11
made of a thermosetting resin such as an epoxy resin.
The conducting wire of each primary coil
4
is connected at one end thereof with a corresponding module connector terminal
10
a
that is one of three first ends of a first wire
10
A, and the other or second end of the first wire
10
A forms a connector terminal
10
b
. The connector terminal
10
b
is electrically connected with an external connector terminal through which it is finally connected with a power supply (not shown) such as the battery of a vehicle. The conducting wire of each primary coil
4
is connected at the other end thereof with a module connector terminal
10
c
that is one end of a corresponding one of three second wires
10
B, and the other end of each second wire
10
B forms a connector terminal
10
d
. The connector terminal
10
d
of each second wire
10
B is electrically connected with an external terminal through which it is finally connected with a corresponding terminal of a switching module (not shown), e.g., a collector of a corresponding one of power transistors which constitute the switching module.
The conducting wire of each secondary coil
6
is connected at its opposite ends with external output terminals
8
b
of the high-voltage towers
8
a
, respectively.
The first wire
10
A and the second wires
10
B are integrally formed with each other through a resin to form the wiring module
9
, as shown in FIG.
9
.
With the known ignition apparatus for an internal combustion engine as constructed above, the respective transformers
1
A,
1
B,
1
C are arranged in the casing
8
with which the wiring module
9
is integrally formed beforehand, and thereafter the conducting wire of each primary coil
4
is connected at one end thereof with a corresponding module connector terminal
10
a
of the first wire
10
A, and at the other end thereof with the module connector terminal
10
c
of a corresponding second wire
10
B. Also, the conducting wire of each secondary coil
6
is connected at its opposite ends with the corresponding external output terminals
8
b
of the high-voltage towers
8
a
. Then, a resin such as an epoxy resin is casted into the casing
8
under a vacuum atmosphere, and solidified or cured in a curing oven at a high temperature to form the resin portion
11
. In this manner, the fixing of the respective transformers
1
A,
1
B,
1
C and the insulation of a high voltage can be achieved.
Now, the operation of the known ignition apparatus
1
for an internal combustion engine as constructed above will be explained below.
When coil drivers (not shown) such as power transistors are driven by a control signal from a control unit (not shown) of the internal combustion engine, a primary current flowing through the primary coils
4
is controlled to be supplied and interrupted in an appropriate manner by the coil drivers.
That is, the coil drivers are turned off at prescribed ignition timing of the internal combustion engine thereby to cut off the primary current of the corresponding primary coils
4
, whereupon counterelectromotive forces are generated in the primary coils
4
whereby high voltages are produced in the secondary coils
6
of the transformers
1
A,
1
B,
1
C. As a result, the high voltages thus produced are impressed on the spark plugs (not shown) connected with the secondary coils
6
, whereby air fuel mixtures in the unillustrated engine cylinders are dielectrically broken down, and fired by sparking of the corresponding spark plugs caused by discharging of secondary current flowing through the respective secondary coils.
With the known ignition apparatus
1
for an internal combustion engine as described above, when the respective transformers
1
A,
1
B,
1
C are arranged in the casing
8
, the relative positions among the module connector terminals
10
a
of the first wire
10
A, the module connector terminals
10
c
of the second wires
10
B of the wiring module
9
integrally formed with the casing
8
and the respective ends of the conducting wires of the primary coils
4
have not been fixed, and hence the positional adjustment of the module connector terminals
10
a
and the one ends of the conducting wires of the respective primary coils
4
as well as the positional adjustment of the module connector terminals
10
c
and the other ends of the conducting wires of the respective primary coils
4
are individually performed and then welded to each other through welding operation. Therefore, there arises the following problem. That is, the positional adjustment of each primary coil
4
and the wiring module
9
takes time, and in particular, the increased number of transformers
1
A,
1
B,
1
C results in an accordingly increased time for connecting operation.
SUMMARY OF THE INVENTION
The present invention is intended to obviate the above-mentioned problem, and has for its object to provide an ignition apparatus for an internal combustion engine in which the positional adjustment of primary coil connector terminals and module connector terminals can be performed with ease, thus making it possible to smoothly carry out the operation of electrically connecting primary coils and a wiring module with each other.
Bearing the above object in mind, the present invention resides in an ignition apparatus for an internal combustion engine including: a casing; a closed magnetic circuit core incorporated in the casing and having sides; a primary coil arranged to surround a part of the sides of the closed magnetic circuit core and having primary coil connector terminals at its opposite ends; and a secondary coil arranged to surround the primary coil and having secondary coil connector terminals at its opposite ends for outputting a high voltage when a current supplied to the primary coil is turned on and off. A wiring module is provided which has module connector terminals connected with the primary coil connector terminals. The wiring module is composed of a plurality of wires integrally formed with each other through a resin for supplying the current to the primary coil. A resin portion is filled in the casing to fixedly attach the closed magnetic circuit core, the primary coil and the secon
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