EP1001220B1 - Glow pin plug - Google Patents

Abstract

The glow plug has a heater rod (1) with internal heater coil and if appropriate at least one regulating coil, whereby the heater rod is insulated from the glow plug body (3), and a plug or screw connection (4) for a supply voltage. The plug connector has an electronic component (6), pref. a chip, with connections (7,8,9) to the supply voltage, glow tube and body, that acts as a regulating/control element for the glow plug functions for heating or measuring the ion current in a combustion chamber side of the heater rod. An Independent claim is also included for plug connector for a glow plug.

Description

The invention relates to a glow plug with a heating rod with glow tube and internal heating coil and possibly at least one control coil, with a glow plug body, wherein the heating element is insulated from the glow plug body, and with a plug or screw to the supply voltage, an electronic component for controlling the current the glow plug having a connection to the supply voltage, having a connection to the glow tube and a connection to the glow plug body, and a corresponding plug connection for a glow plug.

Such a glow plug is known from EP 0657698 A2.

In the known glow plug, a series circuit is provided, which leads from the plug or screw terminal, which is the supply voltage via a PTC resistor, the coil, the glow tube and the body to ground.

It is known to operate conventional glow plugs with external conventional control unit. As a result, the function of a conventional glow plug can be extended beyond the actual annealing to ion current measurement and / or to sensor functions. As a result, further connections, such as expensive plug-in connections with multi-pole coaxial plug for controlling necessary; Folgeschwierigkeiten arise from the laying of additional lines, since, for example, the ground line of each glow plug must be laid with. Here, the tight space in the engine compartment are extremely aggravating. At the same time there is an increased risk of the occurrence of contact resistance as well as voltage loss due to the necessary length of the cable. Finally, conventional glow plugs with conventional control unit can not readily be operated on electrical systems of higher voltage (eg 42 volts).

The object of the invention is to overcome the known from the prior art and listed disadvantages; In particular, it is also in the case of a mass-free glow plug, for example, for ion current measurement to make a ground line back to the control unit unnecessary; equally intended for a vehicle electrical system voltage of, for example, 14 volts designed glow plug can be operated on a vehicle electrical system voltage of 42 volts, for example; at the same time the glow plug connection should be maintained in a known manner, in particular the single-pole plug-in system; Finally, it should be possible to use the current path for operating the glow plug for the transmission of sensor signals. Here, the structure of the glow plug should be designed so that a cost-effective mass production on the existing systems is possible, with the assembly of similar components with substantially the same method while maintaining the cycle time is of particular importance.

This object is achieved by a glow plug according to claim 1 and by a plug connection according to claim 6.

Further advantageous embodiments of the glow plug according to the invention are the subject matter of claims 2 to 5.

The integrated electronics in the candle, for example, when used as an ionic current candle (isolated structure between conventional heating element and engine mass, eg cylinder head) otherwise required for a operation ground return to the control unit omitted by the voltage applied will decide whether to be measured ( Insulation against ground) or glow operation is desired (bridging the insulation inside the glow plug and thus short to ground).

In addition, with the help of the integrated circuit, for example, a periodic switching or blocking of the current path can be done, for example, designed for a for example 11 V operating voltage Glow plug or designed for this voltage heating / control element to operate at higher vehicle electrical system voltages. By the periodic switching then a voltage is generated, which corresponds in its rms value again the nominal operating voltage of the design.

Furthermore, e.g. Also, a circuit can be realized in the way that a sensor integrated in the glow plug via the same supply terminal of the heating or control elements supplied or the measurement signal can be tapped.

• Figur 1 ist die schematische Wiedergabe einer bevorzugten Ausführungsform einer erfindungsgemäßen Glühkerze in teilweisem Längsschnitt mit Querschnitten B-B, A-A und die -D;
• Figur 2 ist ein teilweiser Längsschnitt durch einen erfindungsgemäßen Steckanschluß, gegenüber Figur 1 um 90° gedreht, mit einer Querschnittswiedergabe C-C;
• Figur 3 ist ein Schaltbild zur Taktung

The invention will be explained in more detail with reference to the following figures.

• Figure 1 is the schematic representation of a preferred embodiment of a glow plug according to the invention in partial longitudinal section with cross sections BB, AA and the -D;
• Figure 2 is a partial longitudinal section through a plug connection according to the invention, compared to Figure 1 rotated by 90 °, with a cross-sectional reproduction CC;
• FIG. 3 is a circuit diagram for timing

In the following, a glow plug with insulation between the heating element and engine ground, for example, for use for measuring the ion current is described with reference to the figures; as heating rods, the known heating rods are suitable, such as those with metal annealing tube or glow tube (at least partially) made of conductive ceramic u.ä ..

The heating element (1) can be manufactured on existing series devices, this also applies to the pin (1.1), which produces the later contact to the plug connection (4).

Heating rod (1) can be pressed into the body (3) as before. The insulating layer (2) can be applied either to the body (3) or to the heating element (1). This unit can be completely automatically assembled and tested for function.

The insulating tube (15) serves as Berührschutz and as a brake for the Umspritzmasse (16) and is pressed as the next step between the heating element and the body. The material is preferably a temperature-resistant plastic.

The plug connection (4) is identical in the connection area to previous versions. Accordingly, it has a connector pin with or without thread on the connection side.

In the front region of the plug connection (4) has a recess as a mounting platform (4.1) for the ceramic carrier (5) on which the electronic component (6) is pre-assembled. These two components together will be on the

Plug connection (4) in the region of the mounting platform (4.1) preferably applied by gluing. As another unit, the busbars (11) and (12) of a plastic housing (13) are encapsulated and as compl. Component be pressed onto the plug connection (4). So that the component can be mounted in the correct position, a twist protection (13.1) and the length stop (13.2) are provided.

The connections on the electronic component - e.g. Supply voltage terminal (7), connection to the glow tube (8) and ground terminal (9) - are preferably connected to the bonding process with the respective contact parts plug connection (4), busbar for glow tube (11) and busbar to body (12).

This unit is now shed, for example, with a resin (14) for stabilization.

This completed component plug (4) with electronics etc. can be angliefert as pourgutfähiges component for final assembly.

The plug connection (4) has a bore (4.2) in the axial direction, in which the pin (1.1) is pressed by the heating element and the electrical contact to the inner pole (1.2) from the heating element (1) establishes.

Furthermore, the busbar (11) with the glow tube and the busbar (12) to the body (3) are connected.

This unit, heating element (1) with body (3) and the plug connection (4) is placed in an injection mold and with encapsulation (16), for. overmoulded with PA 6.6.

The circumferential groove (17) on the body (3) serves as an additional form fit for a more secure introduction of force into the encapsulation (16).

Example 1: Ground contacting in glow operation of a glow plug with electrically insulated heating rod for ion current measurement:

It is known to provide for the operation of a glow plug with insulated heater except the power supply (plus contact) and the ground line back to the control unit or to another ground point. This means practically double the cabling effort with corresponding losses and possible errors.

The glow plug according to the invention can now decide, for example with the help of the integrated electronics due to the voltage applied to the terminal, if glow operation is desired (applied voltage eg less than 16 V) or if an ion current is to be measured (applied voltage eg greater than 20 V). In the event of the annealing operation then switches the electronics, for example, the glow tube with the glow plug body briefly, which is given the necessary for the operation ground fault. In the other case, the ion current measurement, this compound is disconnected, so that the projecting into the combustion chamber of the engine part of this is electrically isolated and thus can act as an electrode. The flowing current (eg via the glow plug and the ions in the combustion chamber to the mass, eg cylinder head) can then be tapped via the same connection in the control unit and further processed as a measurement signal.

Example 2: Operation of a higher voltage power element designed for a given voltage:

By means of the integrated electronics can be clocked by periodic switching an applied voltage so that the rms value of the output voltage corresponds to the rated voltage of the glow plug. As a result, a new design for higher voltages is not necessary. This has the further advantage that the otherwise required for higher voltages glow elements lower cross sections can be avoided, which have a negative impact on the life of the glow plug (Figure 3).

Example 3: Alternate connection of a sensor signal and the operating voltage to the glow plug connection:

By means of the integrated electronics, the signal of a built-in glow plug sensor can be placed on the connection for operation of the glow plug, whereby a separate connection is avoided. For intermittent measurement / operation, e.g. the case distinction, similar to that described in Example 1, grab.

In further preferred embodiments, the system glow plug electronics 6 connector 4 is modular: On the one hand, connector 4 with integrated electronics 6 may be formed for mating with the glow plug body 3 with heating element 1 (two-piece design). On the other hand, the electronic component 6 may be provided with a plug-in connection to the connector 4 and a plug-in connection to the glow plug body 3 with heating element 1 and connected by mating with connector 4 and body 3 with heating element 1 (three-part design).

The integration of the control electronics according to the invention into the glow plug overcomes the disadvantages enumerated in the prior art. The connector concept according to the invention allows automatic series production Existing plants, the individual building components are pourable, which is extremely advantageous for mass production and storage. By avoiding additional lines, the system according to the invention is less susceptible to faults, wherein in particular contact resistances and voltage losses due to cable length are avoided. At the same time the standard dimensions of glow plugs (wrench size) are not exceeded, so that no special tools for glow plug mounting are required; the glow plugs according to the invention can also be operated on control units without ion current electronics.

Claims (6)

1. Glow plug with a heating element (1) with a glow tube and a heating coil inside and if necessary at least one control helix, with a glow plug body (3), in which the heating element (1) of the glow plug body (3) is insulated, and with a plug or screw connection (4) to the supply voltage, which has an electronic component (6) for controlling the current of the glow plug with a connection (7) to the supply voltage, with a connection (8) to the glow tube and with a connection (9) to the glow plug body (3), characterised in that the electronic component (6) is a chip, which is made as a regulating/control element to measure the stream of ions in the area of the heating element on the combustion chamber side.
2. Glow plug according to claim 1, characterised in that the plug or screw connection (4) has an assembly platform (4.1) on which the chip is fixed to a ceramic carrier (5).
3. Glow plug according to claim 1 and/or 2, characterised in that the connection (8) to the glow tube is made through a conductor rail (11) with the glow tube and the connection (9) to the body (3) through a conductor rail (12) with the glow plug body (3).
4. Glow plug according to at least one of claims 1 to 3, characterised in that the plug or screw connection (4) has a hole (4.2) in an axial direction, in which a pin (1.1) of the heating element (1) engages and produces the electrical contact to an internal pole (1.2) of the heating element (1).
5. Glow plug according to at least one of the previous claims, characterised in that the plug or screw connection (4) is prefabricated as a component which may be bulky and joined to a heating element (1), which is also prefabricated, with the glow plug body (3) by forming connections.
6. Plug connection for a glow plug, which has a heating element (1) with a glow tube and a heating coil and if necessary at least one control helix and a glow plug body (3), in which the heating element (1) is insulated from the glow plug body (3), with an electronic component (6) for controlling the current of the glow plug with a connection (7) to the supply voltage, with a connection (8) to the glow tube and a connection (9) to the glow plug body (3), characterised in that the electronic component (6) is a chip, which is designed as a regulating/control element for measuring the stream of ions in the area of the heating element on the combustion chamber side.

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