WO2012072313A1

WO2012072313A1 - Ignition coil

Info

Publication number: WO2012072313A1
Application number: PCT/EP2011/067102
Authority: WO
Inventors: Martin Maier; Klaus Ries-Mueller; Nikolaus Hautmann
Original assignee: Robert Bosch Gmbh
Priority date: 2010-12-02
Filing date: 2011-09-30
Publication date: 2012-06-07
Also published as: DE102010062356A1; BR112013013378A2; CN103222018A

Abstract

The invention relates to an ignition coil (1) for an internal combustion engine, comprising: a housing (2) made in particular of plastics material, a winding assembly (3) having a primary winding (30) and a secondary winding (32), and an ignition sensor (4) for detecting an ignition, wherein the ignition sensor (4) is arranged adjacent to the secondary winding (32) on a wall (20), in particular an inner wall (21), of the housing (2).

Description

Description title

ignition coil

The present invention relates to an ignition coil for internal combustion engines and a manufacturing method for ignition coils. In particular, the present invention relates to a device in an ignition coil for detecting a successful ignition.

Ignition coils in internal combustion engines ensure that

combustible gas (mixture) is ignited at a predefined time. For this purpose, generally arranged at a certain distance from one another electrodes are arranged in the combustion chamber and this through the

Ignition coil is acted upon at a given time with a potential difference, due to which a spark breaks through the free path between the electrodes and ignites the gas (mixture). The operating principle and the function of generating the necessary

Voltage pulses used primary and secondary windings in an ignition coil are assumed to be known in the following. The known ignition coils have in common that a feedback of the module via an ignition done either not at all or only by relatively complicated measures or components, which leads to high costs.

Disclosure of the invention

The ignition coil according to the invention with the features of claim 1 has the advantage over the known ignition coils, that it provides a simple, inexpensive and easy to install solution for detecting a successful ignition. Here, the magnetic or electrostatic field generated by the Sekundärzündspule by means of an adjacent to

Secondary winding arranged ignition sensor detected, the resulting electrical signals, for example via a connecting line to an evaluation unit and there determines the ignition timing. Here, a production-safe dimensioning of the distance between the secondary winding and the ignition sensor is crucial, so that on the one hand the entry of the ignition signal is secured, on the other hand, no impairment of the ignition process in particular by a

Skipping the charge of the ignition pulse is risked on the ignition sensor. In the context of the present invention, "adjacent" is therefore understood to mean, in particular, a functional interaction between the

Secondary winding or excited by them fields and the ignition sensor is guaranteed. The ignition sensor itself and its connecting lead are preferably made of an electrically conductive material, e.g. Made of metal or a metal alloy. Preference is given to low-resistance material alloys, such as e.g. Cu alloys or Sn alloys, suitable.

The dependent claims show preferred developments of the invention.

According to a particularly preferred embodiment, the ignition sensor is integrally connected to the housing wall of the ignition coil. By "integral" in connection with the present invention is either an integral one

Manufacturing (in the case of components with the same materials) or a partial introduction of the substance to be applied (for example metal) into the carrier material (for example plastic). In this case, parts of one substance diffuse into, in particular, microscopically small cavities of the other substance and thus ensure a permanent and stable connection, without requiring further adhesion promoters.

By the connecting line as well as the ignition sensor according to the invention vapor-deposited or sprayed onto the housing material, contact points between connecting line and ignition sensor can be omitted by both being created as an integral component by vapor deposition. In addition, resulting in the Zündsensorgeertigung invention geometric degrees of freedom.

Structures adapted in particular to the geometry of the coil can be produced in a highly precise and uncomplicated manner, for example, by means of a corresponding design of the housing wall and subsequent vapor deposition. More preferably, the geometry of the ignition sensor is adapted to the secondary ignition coil such that the ignition sensor substantially along in the axial direction the entire length of the secondary winding is located. This results in a high degree of signal sensitivity of the ignition sensor for the current flowing through the secondary ignition ignition pulse. In this case, it is also advantageous to configure the ignition sensor flat, ie to provide a certain minimum dimension of the ignition sensor in the circumferential direction of the coil as well. For example, the surface of the ignition sensor may correspond substantially in a plane of the projection surface of the secondary winding perpendicular to the secondary winding. The surface of the ignition sensor can be made substantially rectangular and, for example, in the case of a substantially cylindrically configured secondary winding envelope surface, it likewise surrounds part-cylindrical or cylindrical in a certain angle sector. This results in a particularly high degree of signal sensitivity of the ignition sensor for the flowing through the secondary ignition coil

Ignition current. Alternatively, the area may also be substantially round or in the

Be substantially oval-shaped.

By according to a preferred embodiment, the ignition sensor as well as the connecting lines on the housing wall, in particular on an inner side, vapor-deposited and / or sprayed on, moreover, neither a separate attachment of the ignition sensor in the housing nor a connection of the ignition sensor to the electrical connection line, in particular via or under the coil, necessary. By the process of application, the requirements for the mechanical stability of the ignition sensor and any other electrical components (eg connecting cables) are significantly lower, as they never independent of the housing wall (eg during manufacture or before the introduction of the ignition sensor in the housing of the ignition coil ) are mechanically stressed. Thus, the sizing of the

Ignition sensor alone to meet the electrical requirements, which in turn material and weight savings (especially copper and

Insulation material) brings with it. Alternatively, the ignition sensor can also be applied to an outside of the housing wall, but should then be protected against environmental influences. However, it is preferable to attach the ignition sensor to the inside, since a signal strength increases with the vicinity of the ignition sensor to the high-voltage-carrying Wcklung. However, in terms of manufacturing technology and in terms of resistance to thermal and mechanical stresses, it may also be advantageous to carry out the connecting line of the ignition sensor essentially in accordance with the structural shape of the ignition sensor itself. Thus, there are no or less cross-sectional jumps between the ignition sensor and his

Connecting line and thus no or less critical weak points for especially thermally induced material stresses in the electrical conductors. More preferably, the ignition sensor is provided on the wall of the housing such that the ignition sensor is not only arranged in the region of a jacket of the secondary winding, but also on at least one further, perpendicular to the lateral surface arranged wall is pulled up. In this way, in particular, an area of the ignition sensor can be increased.

More preferably, the ignition coil is a single spark coil or a

Double coil. The ignition coil can be designed as Kompaktzündspule or as a pencil ignition coil. The inventive method for producing an ignition coil with the

Features of claim 9 has the advantage over the known methods that it provides a simple, inexpensive and easy to install solution for manufacturing a device for detecting a successful ignition in an ignition coil. The fixation of the ignition sensor, which can also be incorporated as a separate component in the housing of the ignition coil, for example, by gluing, riveting, welding, caulking or other form-fitting attachment methods with the plastic of the housing. Alternatively or additionally, the dimensions of the ignition sensor can be selected so that the ignition sensor is clamped in the housing of the ignition coil, for example in the edges and so not only fixed, but also can be easily and precisely positioned. For this can also

corresponding structures (for example, cavities) and, for example, latching lugs may also be provided on the inside of the housing.

In all embodiments of the present invention, it is also possible, even at least partially equidistant to the inside of the housing To make envelope of the secondary winding, and so provide a positioning aid for the ignition sensor relative to the secondary winding.

According to a further embodiment of the method according to the invention for producing an ignition coil, the arranging and fixing takes place by

Applying, in particular vapor deposition or spraying an ignition sensor on the surface of a housing. According to this method, it is possible to use metallic structures such as e.g. Tracks on non-metallic

Support materials z. B. plastic and ceramics. In this case, preferably, the surface of the housing of the ignition coil to be provided with the ignition sensor and / or with tracks is locally e.g. Roughened by laser to ensure the adhesion of the conductor material, from which the ignition sensor and possibly its connecting cables exist. Subsequently, the metal to be applied is melted and sprayed or vapor-deposited by means of pressure on the surface.

The spraying or vapor deposition of the metal on the housing surface can be carried out in the manner of a plasma process, flame spraying or cold gas spraying.

By suitable dimensions, cross sections and metallurgical

Composition, the applied conductive elements can be adapted to their respective application. With suitable process control, the housing of the ignition coil is not affected and there are no conductive metal deposits at unintentional points of the housing.

After introduction and / or application of the ignition sensor in the housing of the ignition coil, the winding assembly can be introduced into the housing. Subsequently, the electrical connections of the windings and the ignition sensor can be guided to their respective terminals on the outside of the housing and the winding assembly are mechanically anchored in the housing. This can for example be done by the

Winding assembly is embedded in cast resin. Of course, the mechanical fixation of Wcklungsbaugruppe also in addition to

followed by casting with cast resin. Such a method is particularly advantageous in mass production, as is generally used in ignition coils for internal combustion engines. In addition, the process can be easily automated by using robots. Significant advantages are in the aforementioned method, inter alia, in the chemical and mask-free production.

An inventive production of ignition coils allows the

cost-effective production of even smaller quantities, which is crucial for ever shorter product life cycles. By saving from

Cable sheathing and other materials as well as the lack of chemistry in the production of the demand for environmentally friendly manufacturing processes and components in the automotive industry is satisfied.

drawing

Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. In the drawing is:

Figure 1 is a perspective view of an ignition coil according to a first embodiment of the present invention;

Figure 2 is an interior view of the ignition coil according to the first

Embodiment;

FIGS. 3a and 3b show a structural representation of an ignition sensor according to FIG

a second and third preferred embodiment;

Figur 4a to 4g advantageous embodiments of the shape of the

Ignition sensor.

Preferred embodiments of the invention

Hereinafter, an ignition coil 1 and an underlying manufacturing method according to a first embodiment of the invention will be described with reference to Figures 1 and 2. FIG. 1 shows an external perspective view of an ignition coil 1 according to the invention. The upper part of the picture shows the housing 2 in which the winding assembly is arranged. The housing 2 is essentially made of plastic, the properties of the operating conditions

Use in the vehicle suffice. Below the housing, a shaft is arranged, whose underside ends with a spark plug connection 7.

2 shows an interior view of the housing 2 of the ignition coil 1. Within the housing 2, a Wcklungsbaugruppe 3 is arranged, which has on its outside a recessed into a secondary winding carrier 33 secondary winding 32. Within the secondary winding carrier 33 is coaxial one

Primary winding 30 embedded in a primary winding carrier 31. Preferably, the surface of the primary winding carrier 31 and the primary winding 30 and the surface of the secondary winding carrier 33 and the

Secondary winding 32 co-planar, so aligned.

Below the Waklungsbaugruppe 3 an ignition sensor 4 is sprayed onto an inner side 21 of the housing 2. The ignition sensor 4 is of planar shape, with its length (in the direction of a coil longitudinal axis X-X) with that of the

Secondary winding carrier 33 matches. A connecting line 5 of the ignition sensor 4 is also sprayed onto the inner side 21 of the housing 2. The connecting line 5 extends over the side on which the ignition sensor 4 is arranged, and continues at the perpendicular to this oriented end wall 20 of the housing 2, on which they are for connection to electrical

Peripheral is led out of the housing 2. Both ignition sensor 4 and lead 5 are made of conductive material, e.g. Copper, made. 2, the connecting line 5 has a lower material thickness than the ignition sensor 4.

At the point at which the connecting line 5 is led out of the housing 2 for connection to the electrical periphery, a plug 6 with a contact pin 60 is provided on the outside of the housing 2. In this case, the contact pin 60 can likewise be embedded in the surface of the plug 6 in an analogous manner to the ignition sensor 4 and its connecting line 5, integrally with the connecting line 5 of the ignition sensor 4 be connected. This eliminates further manufacturing steps and

Material joints. The connection of the connecting line 5 to the plug pin 60 can be exemplified by "cold contact", press contact,

Insulation displacement contact or by a material connection such.

Welding or soldering done.

The winding assembly 3 is cast by casting resin 8 in the housing 2. On the one hand, the casting resin 8 ensures a mechanically permanent and reliable positioning of the winding assembly 3 in the housing 2, on the other hand, it can be designed in terms of its material properties so that it ensures the electrical insulation and dielectric strength between the primary winding 30 and the secondary winding 32 and also as a dielectric Capacitance of the through the secondary winding 32 and the ignition sensor. 4

trained condenser favors.

Thus, according to the invention an ignition coil 1 can be obtained with a simple and inexpensive to manufacture ignition sensor 4. In particular, in the case of single-spark coils, a position of the crankshaft and thus a phase detection can be carried out by detecting whether an ignition coil arranged in a cylinder has ignited. The ignition detection is performed here by a capacitive tap adjacent to the secondary winding, wherein the ignition sensor 4 is preferably integrally formed on an inner side 21 of the housing 2. If necessary, an area of the ignition sensor 4 may also be on the wall portions of the housing 2, which are perpendicular to

Coil longitudinal axis X-X are to be pulled up.

FIG. 3a shows a cross-sectional view through a second embodiment of the invention, which is basically similar to that shown in FIG. However, in this case, the ignition sensor is located on a cylindrical partial surface which is coaxial with the cylindrical envelope surface of the secondary winding 32. The

Coil longitudinal axis X-X of the secondary winding 32 is perpendicular to the plane of the drawing. An ignition sensor 4 is located on the substantially cylindrically shaped inner side 22 of the housing 2. It is arranged equidistant from the cylindrical envelope surface of the secondary winding 32, in that it also has the shape of a cylinder jacket section and a

Circumferential angle α of the secondary coil surface surrounds. This design provides a high level of sensitivity for the detection of ignition by the ignition sensor.

FIG. 3b shows a third exemplary embodiment, in which the ignition sensor is provided both on a base surface and on two side surfaces surrounding the winding assembly 3. As in FIG. 3 a, the ignition sensor 4 of the third exemplary embodiment is also arranged on the inside of the housing 2, as a result of which it is particularly well protected.

FIG. 4 shows further advantageous embodiments of the geometrical design of the ignition sensor in comparison to a flat, rectangular design (FIG. 4g). Shown are linear tracks, which in

Meander shape (Figures 4a and 4b), as a closed or open, round or substantially rectangular conductor loops (Figures 4c, 4d, 4e and 4f) are executed. These shapes ensure that a larger area is tapped by the ignition sensor 4, but less coherent material is used. As a result, on the one hand material can be saved and on the other hand thermally induced stresses can be reduced.

Claims

Ignition coil (1) for an internal combustion engine comprising:

a housing (2), in particular made of plastic, and a winding assembly (3) with a primary winding (30) and a

Secondary winding (32)

marked by

an ignition sensor (4) for detecting an ignition,

wherein the ignition sensor (4) adjacent to the secondary winding (32) on a wall (20), in particular an inner wall (21) of the housing (2) is arranged.

Ignition coil (1) according to claim 1, wherein the ignition sensor (4) is formed integrally with the wall (20) of the housing (2), in particular by means of

Vapor deposition and / or spraying, in particular in a plasma process and / or cold gas spraying.

Ignition coil (1) according to claim 1 or 2, wherein the ignition sensor (4) is designed as a substantially planar conductor track preferably as a straight shape or as a meandering shape or as a closed or open conductor loop.

Ignition coil (1) according to claim 1 or 2, wherein the ignition sensor (4) in the form of a compact, in particular substantially rectangular, surface is configured.

Ignition coil (1) according to one of the preceding claims, wherein the surface of the ignition sensor (4) of an envelope surface of the secondary winding (32) is designed accordingly and in particular in a with the envelope surface of the secondary winding (32) corresponding cylindrical surface.

6. ignition coil (1) according to any one of the preceding claims, wherein the ignition sensor (4) has a length (L1) in the axial direction (X-X) of

Secondary winding (32), which is at least half, preferably equal to or greater than a length (L2) of the secondary winding (32).

7. ignition coil (1) according to any one of the preceding claims, wherein the ignition sensor (4) has a connecting line (5) which is formed integrally with the wall (20) of the housing (2), in particular vapor-deposited or /, or integral with the ignition sensor (4).

8. Ignition coil (1) according to one of the preceding claims, wherein the

Ignition coil (1) is a single spark coil or double spark coil.

9. A method for producing an ignition coil (1) comprising a housing (2), a winding assembly (3) having a primary winding (30) and a secondary winding (32) and an ignition sensor (4),

the method comprising:

Arranging and fixing the ignition sensor on a wall (20) of the housing (2) adjacent to the secondary winding (32).

10. The method of claim 9, wherein the ignition sensor (4) and / or a

Connecting line (5) by means of vapor deposition or spraying integrally on the wall (20) of the housing (2) adjacent to the secondary winding (32), in particular in a plasma process is applied.