Information
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Patent Grant
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6227186
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Patent Number
6,227,186
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Date Filed
Tuesday, November 2, 199924 years ago
-
Date Issued
Tuesday, May 8, 200123 years ago
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Inventors
-
Original Assignees
-
Examiners
Agents
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CPC
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US Classifications
Field of Search
US
- 123 634
- 123 635
- 123 195 C
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International Classifications
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Abstract
An ignition system for an internal combustion engine is able to operate without malfunctions, even under unfavorable surrounding conditions, in particular intensive attack by spray water. To that end, the ignition system, projecting into a compartment of a cylinder head, is provided with a protective covering in which are formed a connecting duct that is connected to the compartment, and a vent duct leading into the atmosphere. Both ducts are interconnected by a storage of the ignition coil. Water penetrating into the ignition coil is caught in the storage and evaporated in such a way that no malfunctions occur at the ignition coil. The ignition system is preferably used in manufacturing automobiles.
Description
BACKGROUND INFORMATION
German Patent No. 39 20 080 described an ignition system for an internal combustion engine in which a spark plug is inserted into a spark-plug compartment (well) of a cylinder head of the internal combustion engine.
A cylinder-head cover is placed on the cylinder head, with the interposition of a gasket. Above the spark-plug compartment, the cylinder-head cover has an installation opening into which is inserted an ignition coil that is connected to the spark plug by way of a connecting plug.
If spray water, e.g. from a high-pressure cleaner, acts upon the ignition coil, this water can get through the installation gap into the installation opening, and from there into the spark-plug compartment. This can occur in particular when the cylinder head is heated to above 100° C. due to the operation of the internal combustion engine, and, during the standstill phase of the internal combustion engine, is cooled off to the ambient temperature. In so doing, the air volume in the spark-plug compartment and the installation opening contracts; an underpressure develops which evens out due to advancing air and moisture along the contact area of the ignition coil. The moisture thus introduced forms a liquid pool around the spark plug, and can impair the high-voltage transmission of the ignition coil, which can result in malfunctions of the ignition system.
SUMMARY OF THE INVENTION
In contrast, the ignition system of the present invention for an internal combustion engine has the advantage that the above-mentioned shortcoming is avoided to a satisfactory degree.
To that end, in the ignition system, the ignition coil is inserted, in a sealed manner, into the installation opening of the cylinder-head cover, thus preventing the entrance of water along the installation opening. In addition, the compartment having the spark plug is vented via a ventilating system of the ignition coil, so that no underpressure can occur any longer in the compartment when the internal combustion engine cools off, and thus there is no suction effect on the water present at the ignition coil.
Water, which because of unfavorable conditions such as the direct blasting of the ignition coil with a high-pressure cleaner, finds a way in small quantities through the ventilation system, is collected in a storage device of the ventilation system, and with the heating of the internal combustion engine during its operation, is evaporated and released.
In this manner, a particularly operationally-reliable ignition system is implemented.
BRIEF DESCRIPTION OF THE DRAWING
The FIGURE shows parts of the ignition system according to the present invention in a sectional view.
DETAILED DESCRIPTION
As shown in the FIGURE, an ignition system
11
of an internal combustion engine for contacting a spark plug fixedly mounted in the internal combustion engine contains, as an important component, an ignition coil
12
which is inserted in a sealed manner in an installation opening
13
of a cylinder-head cover
16
that is likewise placed in a sealed manner on a cylinder head
14
of the internal combustion engine.
As shown in the FIGURE, in the operating position of the internal combustion engine, lid-shaped cylinder-head cover
16
is horizontally aligned, and bar-type ignition coil
12
is arranged running vertically along a longitudinal axis
17
in the fitting position.
Starting from this fitting position of ignition coil
12
, the ignition coil
12
with a housing
18
and in co-axial arrangement with respect to longitudinal axis
17
, has a partially shown, basically cylindrical housing upper part
19
, a sleeve-shaped lower-lying dome
21
whose diameter is reduced with respect to housing upper part
19
, and a cylindrical sealing band
22
, mounted between housing upper part
19
and dome
21
, whose diameter is between that of housing upper part
19
and that of dome
21
.
While housing upper part
19
is arranged above cylinder-head cover
16
when ignition coil
12
is mounted, sealing band
22
projects region-wise into installation opening
13
of cylinder-head cover
16
. Dome
21
runs partially in installation opening
13
and projects with its free end section into a compartment
23
of cylinder head
14
for contacting ignition coil
12
with the spark plug, supported here in a recessed and stationary manner.
Externally in the region of sealing band
22
and dome
21
, ignition coil
12
has a protective covering
24
which, in a manner not shown more precisely, extends beyond the free end of dome
21
and partially overlaps the spark plug. Protective covering
24
is an elastomeric machined part, made preferably of silicone rubber, and is provided as a sleeve member having a through-passage.
Before ignition coil
12
is mounted on the internal combustion engine, protective covering
24
is slid from the free end of dome
21
onto the dome and sealing band
22
, until it strikes at the front side against a shoulder
26
that is formed on the face on housing upper part
19
at the transition to sealing band
22
. Due to the vertical extension of sealing band
22
, tolerances of the end position of protective covering
24
owing to the sliding-on process are of no importance to the sealing of ignition coil
12
.
Protective covering
24
has a largely constant wall thickness over long areas in its vertical extension, so that its shape here is in relation to that of dome
21
and sealing band
22
, and it surrounds sealing band
22
and dome
21
here with an inner side
27
in a resilient, and thus sealing manner.
However, at one end section
28
of dome
21
adjacent to sealing band
22
, protective covering
24
is set back in a graduated manner from dome
21
, so that formed between an end face
29
of sealing band
22
adjacent to dome
21
, an outer side
31
of dome
21
and inner side
27
of protective covering
24
, is an interspace which is designated as a storage
32
in accordance with its function. The vertical extension of storage
32
corresponds approximately to that of sealing band
22
.
Storage
32
is bounded at one location by a radially projecting semi-cylindrical inner shoulder
33
of inner side
27
of protective covering
24
, the vertical extension of inner shoulder
33
being less than that of storage
32
, so that between end face
29
of sealing band
22
and a boundary surface
34
of inner shoulder
33
opposite end face
29
, there remains a horizontally running gap
36
which opens through into storage
32
.
A connecting duct
37
runs vertically aligned in inner shoulder
33
between gap
36
and a limit stop
38
mounted outside on protective covering
24
, there being a direct connection from connecting duct
37
to compartment
23
via an adjoining recess
39
of cylinder head cover
16
.
Formed opposite inner shoulder
33
, in protective covering
24
, is a grooved, narrow vent duct
41
, designed for the escape of air bubbles, which begins approximately at the same height as boundary surface
34
of inner shoulder
33
, is directly connected here to storage
32
, then runs vertically along sealing band
22
in order, at its end, to run along shoulder
26
of housing upper part
19
in a radial course beyond shoulder
26
, and opens through into the open surrounding space of ignition coil
12
.
Thus, with vent duct
41
, storage
32
and connecting duct
37
, a ventilation system
42
of ignition coil
12
is provided, via which, with the aid of recess
39
provided on cylinderhead cover
16
, compartment
23
is connected to the surrounding space of ignition coil
12
and thus can be vented into the atmosphere.
With the insertion of ignition coil
12
, provided with protective covering
24
, into installation opening
13
, protective covering
24
with limit stop
38
makes contact with a contact area
43
of cylinder-head cover
16
; and circumferential, externally-radially projecting sealing rings
44
of protective covering
24
come in contact with an inner wall
46
of installation opening
13
. The axially displaced sealing rings
44
have slightly different diameters, in order to compensate for tolerances in installation opening
13
.
To further seal off installation opening
13
, protective covering
24
has, in radial extension at its free end section on the ignition-coil side, a curvilinier circumferential collar
47
which overlaps an allocated sealing shoulder
48
of cylinder head cover
16
and shields sealing rings
44
from being directly acted upon by spray water.
If an ignition system
11
, designed in such a manner, is struck intensively by spray water, such as when washing the engine by a high-pressure cleaner, it is impossible to completely prevent water from entering into ignition coil
12
through narrow vent duct
41
. This small amount of seepage water, at the end of vent duct
41
situated in ignition coil
12
, gets into adjoining storage
32
whose size is dimensioned such that this seepage water fills storage
32
only to a small degree in the lower region. Because the ends of connecting duct
37
and of vent duct
41
open through overhead into storage
32
, it is ensured that, first of all, no water can get from storage
32
via connecting duct
37
to compartment
23
, and secondly, the air connection passing through from compartment
23
to the atmosphere is not blocked by the seepage water.
The seepage water in storage
32
can be removed through this air connection by evaporation. This process is further supported by heating of the internal combustion engine during operation.
Claims
- 1. An ignition system of an internal combustion engine, the engine including a cylinder head and a cylinder-head cover situated in a sealing manner on the cylinder head, the cylinder head having a compartment, the cylinder-head cover having an installation opening, the ignition system comprising:an ignition coil at least partially supported in the installation opening and supported in a sealing manner in the installation opening, the ignition coil projecting section-wise into the compartment, the ignition coil including a ventilation system for venting the compartment, the ventilation system having a storage.
- 2. The ignition system according to claim 1, wherein the ventilation system has at least one connecting duct connected to the compartment and the storage.
- 3. The ignition system according to claim 1, wherein the ventilation system has at least one vent duct connected to the storage and to a surrounding space of the ignition coil.
- 4. The ignition system according to claim 1, wherein the ventilation system has at least one connecting duct and at least one vent duct opening through, set apart from each other, into the storage.
- 5. The ignition system according to claim 4, wherein the at least one connecting duct and the at least one vent duct open through overhead into the storage, relative to a fitting position of the ignition coil with a vertically aligned longitudinal axis of the ignition coil.
- 6. The ignition system according to claim 1, wherein the ignition coil further includes a housing having a sealing band, a dome adjoining the sealing band, and an elastomeric protective covering surrounding the sealing band and the dome with a pre-loading, the storage being bounded by the sealing band, the dome and the protective covering.
- 7. The ignition system according to claim 6, wherein an outside of the protective covering has sealing rings of differing diameters for sealing with respect to the installation opening, the protective covering overlapping a sealing shoulder of the cylinder-head cover via a circumferential collar.
Priority Claims (1)
Number |
Date |
Country |
Kind |
298 21 239 U |
Nov 1998 |
DE |
|
US Referenced Citations (6)
Foreign Referenced Citations (1)
Number |
Date |
Country |
39 20 080 |
Jan 1991 |
DE |