DE102019101422B4 - Gas engine spark plug - Google Patents

Abstract

Gas engine spark plug, with a prechamber (14) into which a central power supply electrode (22) projects, and at least one ground electrode (48) present in the prechamber (14) and spaced from the power supply electrode (22) by a spark gap (a), a housing (10), in the interior of which the power supply electrode (22) runs, and at least one sensor (40, 100, 104) for the acquisition of data during the operation of a gas combustion engine, characterized in that an exchangeable electronic unit (10) is installed inside the housing (10). 44) is accommodated, the at least one sensor (40, 100, 104) being coupled to the electronics unit (44) for receiving data recorded by the at least one sensor (40, 100, 104), and the electronics unit (44) being coupled to a Data connection (46) is coupled, via which the electronics unit (44) can be externally connected to a controller for signaling purposes.

Description

The invention relates to a gas engine spark plug, with a prechamber into which a central power supply electrode protrudes, and at least one ground electrode present in the prechamber and spaced from the power supply electrode by a spark gap, a housing inside which the power supply electrode runs, and at least one sensor for detection of data in the operation of a gas internal combustion engine.

Gas-powered combustion engines for static energy systems, in particular natural gas and biogas-powered combustion engines, sometimes run 24 hours a day, seven days a week. This means that these combustion engines have to work reliably. The spark plugs are therefore designed to be extremely robust in order to prevent expensive shutdown of the systems. Such gas engine spark plugs are correspondingly complex and expensive. There are two types of gas engine spark plugs based on the prechamber spark plug principle, active and passive prechamber. The active pre-chambers are supplied with fuel via a special fuel system, while the passive pre-chambers are supplied via the air-fuel mixture in the engine combustion chamber.

As soon as the ground electrode or ground electrodes are worn out so that the electrode gap becomes too large, the gas engine spark plugs must be replaced with new ones.

From the WO 2009/059 340 A1 , of the WO 2007/092 972 A1 and the post-published DE 10 2018 105 181 A1 spark plugs with replaceable ground electrodes are known.

Spark plugs with attached sensors are used in the DE 10 2005 060 139 A1 , of the DE 694 05 788 T2 , of the WO 97/31251 A1 suggested. The generic DE 10 2018 105 182 A1 also shows a sensor integrated in the spark plug.

The object of the invention is to create a gas engine spark plug which has a long service life and ensures inexpensive maintenance of the internal combustion engine.

The above object is achieved by a generic gas engine spark plug, with a housing, inside which the power supply electrode runs, and an exchangeable electronic unit housed inside the housing, as well as at least one sensor for recording data during operation of the gas combustion engine. The electronics unit is coupled to a data connection via which the electronics unit can be connected externally to a controller for signaling purposes.

The gas engine spark plug according to the invention is a so-called smart spark plug, via which data is recorded, possibly stored, processed and / or forwarded. These data relate to physical values that are recorded during operation of the internal combustion engine. The data acquisition of internal combustion engines is a central requirement in order to optimize the operation of the same, e.g. B. to change ignition and combustion processes. This optimization also reduces pollutant emissions. Examples of changes are changes in the combustion process, for example changes in the lambda value or the ignition point. However, the design of the internal combustion engine can also be improved with the aid of the gas engine spark plug according to the invention, for example by optimizing the ignition angle or the nozzle position.

It should be emphasized that the electronics unit can also be used in a gas engine spark plug with a replaceable earth electrode.

Inside the gas engine spark plug there is at least one of the following sensors, namely at least one pressure and knock sensor for detecting the pressure in the combustion chamber and abnormal, because detonating (knocking) combustion, at least one temperature sensor for measuring the temperature in the combustion chamber, including the Antechamber and / or at least one current sensor for detecting the current flowing through the measuring chain, in particular a coil that surrounds a current line in the spark plug. The engine can be adjusted with regard to its ignition and combustion parameters using the sensors and the values determined by them. Furthermore, the operator can be warned if incorrect ignition / combustion occurs or maintenance is required. An engine diagnostic system can be created.

The housing is tubular, for example, and defines the gas engine spark plug on the outside. According to the preferred embodiment, the housing has a channel which leads to the antechamber and in which a sensor is inserted, which is coupled with the electronic unit for signaling purposes. With the aid of the gas engine spark plug according to the invention, therefore, fewer interventions in the engine block or a cylinder head have to be carried out in order to bring sensors to or close to the combustion chamber.

The at least one ground electrode can be held non-destructively removable and replaceable in the gas engine spark plug.

The gas engine spark plug according to the invention is not a disposable part, but also allows the at least one ground electrode to be replaced by a new one. This dismantling and assembly process can be carried out very easily because the gas engine spark plug is designed for this simple assembly and disassembly from the start and the replacement can be carried out using tools without destroying parts.

The at least one ground electrode is preferably detachably housed in a holder which, together with the at least one ground electrode, can be removed from the gas engine spark plug in a non-destructive manner. The ground electrode is safely and precisely positioned inside the gas engine spark plug via the holder and can be removed more easily.

The holder is preferably a reusable part, so that only the ground electrode has to be removed from it and replaced with a new one.

The holder can be accommodated in a central, axial receiving opening and pushed into the receiving opening by means of an insulator pin receiving the power supply electrode. This means that the holder is pushed from the axial end, which is opposite the prechamber, into the interior of the gas engine spark plug in the direction of the prechamber. This is done using z. B. the isolator pin, which thus has a double function. The power supply electrode runs through the insulator pin. In this way, the power supply electrode and holder are pushed together into the interior of the gas engine spark plug via the insulator pin.

The holder is locked on the isolator pin, for example, by a fastening device, e.g. B. a screw sleeve which receives the insulation pin on the inside and pushes it axially into the mounted position and which has a thread on the outside that engages an internal thread in the housing.

The holder and the insulator pin can delimit the antechamber at the rear. “Back” means to the end of the gas engine spark plug remote from and opposite to the prechamber.

The at least one ground electrode can be arranged in the holder so as to be displaceable laterally to the power supply electrode, in particular it can be fixed in the holder with the formation of a press fit. The axial displaceability makes it possible to align the earth electrode laterally exactly to the power supply electrode in order to adjust the spark gap again exactly after replacing the worn earth electrode. The press fit allows the ground electrode to be displaced, but after the displacement it ensures a firm hold of the ground electrode, specifically in every lateral position of the same. This means that you do not need your own fixing screws or the like.

Since the adaptation of the spark gap can be complex for new ground electrodes that have just been inserted, the invention provides for self-adjustment of the spark gap via the displaceable or displaceable ground electrodes. This is achieved in that the at least one ground electrode can protrude laterally outward beyond the holder before being pushed into the receiving opening. During axial insertion into the receiving opening, the contact of the ground electrode with an inside of a housing which defines the receiving opening pushes it inward. The spark gap is optimally set at the same time as the holder and the new earth electrode (s) are installed.

Inside the gas engine spark plug there can be a chamber filled with dielectric coolant, which electrically isolates the system, the chamber preferably being traversed by an electrical supply line which leads to the supply electrode. This insulator is preferably a liquid dielectric fluid.

The coolant-filled chamber has, for example, an inlet and an outlet and there is a flow of coolant through it, that is, cold coolant leads into the chamber and is led out again from the chamber.

On the outside, the gas engine spark plug according to the invention can be defined by the aforementioned tubular housing, which has an overpressure line. Via this overpressure line it is possible that gas from the combustion chamber, which arrives downstream of a seal, can flow out into the open. Due to the interchangeability of the ground electrode, it is necessary to provide seals between the parts to be inserted or between the parts to be inserted and the housing. If, due to the extremely high pressure in the combustion chamber and thus also in the antechamber, gas gets past the seals, this can then flow out.

In the housing, a channel can run up to the antechamber, through which fuel (gas) is injected into the antechamber. The channel can be the channel of the pressure sensor, which can thus be used either to accommodate the sensor or to supply fuel. The spark plug can therefore easily be converted from an active to a passive prechamber spark plug without machining.

• - 1 eine Längsschnittansicht durch eine Variante der erfindungsgemäßen Gasmotorzündkerze,
• - 2 eine Axialansicht durch einen Masseelektrodenhalter, der bei der Gasmotorzündkerze nach 1 eingesetzt wird, und
• - 3 eine vergrößerte Schnittansicht des Halters nach 2.

Further features and advantages of the invention emerge from the following description and the following drawings, to which reference is made. In the drawings show:

• - 1 a longitudinal sectional view through a variant of the gas engine spark plug according to the invention,
• - 2 an axial view through a ground electrode holder, which in the gas engine spark plug according to 1 is used, and
• - 3 an enlarged sectional view of the holder according to FIG 2 .

In 1 a gas engine spark plug of a gas-powered, in particular stationary, internal combustion engine is shown, which is operated, for example, with natural gas or biogas.

The spark plug has a tubular outer housing 10 with a hollow interior into which several parts are inserted. At the axial front end is a cap 12th welded onto the housing, with the cap 12th with a sleeve-shaped section in the central opening in the housing 10 is inserted precisely.

The cap 12th defines a so-called antechamber 14th that have a central opening 16 and optionally a plurality of lateral openings is connected to a combustion chamber and partially protrudes into the combustion chamber.

The case 10 has in the area of the antechamber 14th an external thread 18th which is screwed into an opening in the cylinder head, for example. The screwed-in section of the gas engine ignition unit is also called the igniter head 20th designated.

In the antechamber 14th protrudes centrally, ie along the central axis A. , a power supply electrode 22nd .

The power supply electrode 22nd is part of a power supply line 24 , or connected to one. The power supply line 24 runs within a centrally located isolator pin 26th made of electrically insulating material. Parts or sections of this power supply line 24 can also be achieved by extending the power supply electrode 22nd are formed. For example, the power supply electrode 22nd to the inside of the insulator pin 26th protrude and there with the in 1 Thickened power supply line shown 24 be connected.

The isolator pin 26th protrudes into a coolant-filled chamber 28 and ends there. The power supply line 24 however leaves the isolator pin 26th at the rear end and runs over an insulated section 30th through the chamber 28 through to a cover 32 who made the case 10 closes at this rear end, and runs through this end cover 32 through to the outside, where they are connected to a connecting cable 34 is coupled or merges into this.

The end cover 32 has, for example, a polygonal geometry on its outer circumference, around it on the housing 10 to be screwed on (the corresponding threads are not shown for the sake of simplicity).

The chamber 28 contains cooling fluid, which via an inlet 36 flow in and through an outlet 38 can flow out again.

In particular, a dielectric fluid is used as the cooling fluid.

In the area of the cover, which can be removed, and thus the inside of the housing 10 can close on the back is a current sensor 40 inserted over a coil 42 the one through the power supply line 24 measures flowing current.

In addition, for example, to the sensor 40 on the front, an electronic unit 44 inside the case 10 housed, which can also be removed non-destructively detachable from the gas engine spark plug via the rear end.

The electronics unit 44 is via a data connection 46 looking outside the case 10 runs, can be coupled to a control of the internal combustion engine.

In the antechamber 14th around the side of the power supply electrode 22nd around, are several ground electrodes 48 (see also 2 and 3 ) positioned. The ground electrodes 48 which taper to a point, especially when they are new and unused, have a defined spark gap a Distance from the outer periphery of the power supply electrode 22nd .

The ground electrodes 48 run in particular radially to the central axis A. . In the present case there are three such ground electrodes 48 evenly distributed around the circumference in a holder 50 recorded.

The holder 50 is designed in several parts, but this is only an option. It includes a ring 52 , which the corresponding openings for receiving the ground electrodes 48 has, and one for example on the ring 52 welded sleeve 54 . The sleeve 54 lies like the ring 52 , also on the outside centered in a receiving opening 56 in the housing 10 at.

The receiving opening 56 is the one in the area of the detonator head 20th and the adjoining area, narrower or narrowest section of the opening, which forms the interior of the housing 10 forms.

The holder 50 has a circumferential collar on the inside 58 towards the rear, ie away from the antechamber 14th pointing a conical contact surface 60 trains. At this conical contact surface 60 lies a ring seal 61 (please refer 1 ) between the contact surface 60 and a corresponding mating cone on the insulating pin 26th is pressed together.

At the back end has the sleeve 54 a circumferential collar protruding radially outward 62 . Between this and a paragraph 64 in the opening at which the receiving opening 56 ends and the opening is given a larger cross-section, is another seal 66 positioned that also, like the seal 62 , to seal the antechamber 14th serves.

The opening has the heel 64 in 1 to the right spaced a second paragraph 68 , in which the opening is enlarged one more step to the outside. At this paragraph 68 lies a seal 70 on, by a fastening device in the form of a threaded sleeve 72 axially against the shoulder 68 is pressed. The threaded sleeve 72 has no thread on the inside, only on the outside, and engages in a mating thread 74 on the inside of the case 10 at.

The isolator pin 26th has in the area of paragraph 68 a leap in cross-section (paragraph 76 ) inside. To this paragraph 76 lies the seal 70 on, and the threaded sleeve 74 also protrudes inwards. With screwing in the threaded sleeve 72 into the thread 74 the threaded sleeve migrates 72 axially and takes over the paragraph 76 the isolator pin 26th With.

The threaded sleeve has on the rear face end 72 Recesses 80 , can engage in the pins of a tubular tool to ensure torque transmission.

As just explained, the holder 50 only by axial insertion when inserting the isolator pin 26th into the receiving opening 56 be pushed. The holder is responsible for this 50 as in the lower half in 3 shown trained. Alternatively, this is in 3 using the upper half of the holder 50 can see the holder 50 also an external thread 84 wear, then has the housing accordingly 10 an internal thread in this area. About driver geometries 86 is then screwing in the holder 50 enables. However, this is only an optional variant.

Between the covenant 62 and the case 10 as well as the insulator pin, which has a conical widening in this area 88 has (see 1 ), a space is created 90 into which gas from the combustion chamber can possibly penetrate.

From the room 90 leads a pressure line 92 into the open.

The housing also has 10 a channel 94 that is axially of the chamber 28 starting to the antechamber 14th leads, with the housing 10 at the end of the canal 94 a circumferential groove 96 owns. The holder 50 has a corresponding opening 98 (please refer 3 ) that with the groove 96 radially aligns so that the channel 94 with the antechamber 14th is connected to the flow.

In the canal 94 there is a pressure sensor 100 that has a connection line 102 (for example a cable) to the electronics unit 44 is coupled. It is also possible to have a temperature sensor in the duct 94 to place, the temperature sensor can also be placed in another specific channel. The channel 94 can also be used to inject fuel gas or a mixture of fuel gas and combustion air to transform the system into an active ignition prechamber. In the embodiment shown, however, there is at least one separate temperature sensor 104 provided, which also has its own connection cable 106 with the electronics unit 44 is coupled. Here, too, the housing 10 with a suitable channel to accommodate the temperature sensor 104 and a connecting line 106 be equipped.

The gas engine spark plug has replaceable earth electrodes 48 which can be replaced with new ones if necessary. For this purpose, these ground electrodes 48 together with the holder 50 non-destructive from the housing 10 can be removed and after re-equipping the holder 50 to be reinstated.

The assembly and disassembly as well as the functionality of the gas engine spark plug are explained below.

The cover is used for dismantling 32 removed so that the housing 10 is open at the back. After that the current sensor 40 together with the electronics unit 44 axially pulled out. The connecting lines 102 , 106 can via plug connections 108 automatically from the electronics unit 44 be decoupled. Then the threaded sleeve 72 twisted out and removed, leaving the isolator pin 26th including the power supply electrode 22nd , and the power supply line 24 can be pulled out through the open back.

Is the holder 50 in the housing 10 screwed in (variant according to 3 , upper half), this is unscrewed. Is the holder 50 without a thread 84 carried out, it is carried out by means of a tool with a hook, for example behind the collar 58 engages, axially pulled out.

Subsequently, from the inside through a press fit in the holder 50 seated ground electrodes 48 pushed outwards and pulled out.

The ground electrodes 48 have a mushroom-shaped widening or a corresponding head at their radial outer end 110 , and the holder 50 has a corresponding widened receptacle 112 (please refer 3 ) to hold the head 110 . Radially on the inside of the mount 112 however, the opening in the holder corresponds to the cross section of the corresponding ground electrode 48 forming an interference fit tighter.

There are then new ground electrodes 48 used, but not completely in the corresponding recordings 112 in the holder 50 be pressed in. Rather, the heads should 110 , as in 2 Shown in broken lines, laterally outward from the outer periphery of the holder 50 , here opposite the ring 52 , protrude.

The heads 110 are preferably designed dome-shaped, so that the dome section outwards with respect to the holder 50 protrudes.

The parts are then put back into the housing in reverse order 10 used, where if the holder 50 no thread 84 owns, the holder 50 on the isolator pin 26th is placed, which at its front tip has a corresponding to the inner diameter of the holder 50 has a precisely fitting diameter. In this case the unit is made of an insulator pin 26th and holder 50 together from the back into the housing 10 pushed.

As the heads 110 protrude laterally, they will when they reach the receiving opening 56 have reached, pressed radially inwards with further axial displacement, so that the ground electrodes after they have been fully inserted 48 are in a predefined, precisely set radial position and the spark gap a is reached. The threaded sleeve is used for axial insertion 72 are used, through which more axial pressure can be exerted. When screwing in the threaded sleeve 72 becomes the insulator pin 26th secured against rotation by acting on a polygon 116 trained end which goes into the chamber 28 protrudes, is held. The cap serves as an axial stop for the holder 12th .

Then the electronics unit again 44 and the current sensor 40 axially inserted, and the cover 32 closes the housing 10 .

During operation, the current pressure in the antechamber 14th and thus in the combustion chamber through the pressure sensor 100 can be determined, and abnormal combustion and in particular detonating combustion (knocking event) or non-combustion cycles are detected. The corresponding data are sent to the electronics unit 44 that can process and / or save the data. The data is transmitted without processing via the data connection 46 sent to the engine control.

The same is done with the data received from the temperature sensor 104 and about the current sensor 40 be won. These also become an electronic unit 44 to be processed and / or stored there and in any case forwarded to the engine control.

The ignition point, the course of combustion, temperatures in the combustion chamber, pressures (possibly pressure conditions) in the combustion chamber and the like can be determined from the data obtained. For example, misfires in the prechamber can occur via the pressure sensor 14th determined and determined.

As already explained, the electronics unit 44 If necessary, analyze and forward the received data or just convert and forward the data.

The gas engine spark plug can be used as an alarm sensor that informs the operator of the gas engine after a misfire or knock cycle.

The gas engine spark plug is recyclable and above all because of the exchangeable earth electrodes 48 reusable.

Claims (14)

Gas engine spark plug, with a prechamber (14) into which a central power supply electrode (22) projects, and at least one ground electrode (48) present in the prechamber (14) and spaced from the power supply electrode (22) by a spark gap (a), a housing (10), inside of which the power supply electrode (22) runs, and at least one sensor (40, 100, 104) for recording data during operation of a gas combustion engine, characterized in that inside the housing (10) a replaceable built-in electronics unit (44) is accommodated, the at least one sensor (40, 100, 104) being coupled to the electronics unit (44) for receiving data recorded by the at least one sensor (40, 100, 104), and the electronics unit (44 ) is coupled to a data connection (46) via which the electronic unit (44) can be connected to a controller externally for signaling purposes. Gas engine spark plug after Claim 1 , characterized in that at least one of the following sensors (40, 100, 104) is contained in the gas engine spark plug: - a pressure sensor (100) for detecting abnormal combustion by measuring a pressure in the prechamber (14), - a temperature sensor (104 ) for determining a temperature in the combustion chamber, and / or - a current sensor (40) for detecting a current flowing in the power supply electrode (22), in particular in the form of a coil which surrounds a power supply line (24) in the gas engine spark plug of the gas engine. Gas engine spark plug after Claim 2 , characterized in that a tubular housing defines the gas engine spark plug on the outside and the housing (10) has a channel (94) which leads to the prechamber (14) and in which at least one sensor (40, 100, 104) is inserted, which is connected to the Electronics unit (44) is coupled for signaling purposes. Gas engine spark plug after Claim 1 or 2 , characterized in that a channel (94) runs in the housing (10) up to the prechamber (14) through which fuel can be injected into the prechamber (14). Gas engine spark plug according to one of the preceding claims, characterized in that the at least one ground electrode (48) can be non-destructively dismantled and replaced in the gas engine spark plug. Gas engine spark plug after Claim 5 , characterized in that the at least one ground electrode (48) is detachably housed in a holder (50) which, together with the at least one ground electrode (48), can be dismantled from the gas engine spark plug in a non-destructive manner. Gas engine spark plug after Claim 6 , characterized in that the holder (50) is accommodated in a central, axial receiving opening (56) and can be pushed into the receiving opening (56) by means of an insulator pin (26) receiving the power supply electrode (22). Gas engine spark plug after Claim 7 , characterized in that a fastening device provided with a thread is provided, via which the insulator pin (26) and thereby the holder (50) can be pushed axially into the receiving opening (56). Gas engine spark plug after Claim 7 or 8th , characterized in that the holder (50) and the insulator pin (26) delimit the antechamber (14) at the rear. Gas engine spark plug according to one of the Claims 6 to 9 , characterized in that the at least one ground electrode (48) is arranged laterally to the power supply electrode (22) in the holder (50) so as to be displaceable, in particular is fixed in the holder (50) with the formation of a press fit. Gas engine spark plug according to the Claims 7 and 10 , characterized in that the at least one ground electrode (48) can protrude laterally outward beyond the holder (50) and can be pushed inwards when axially pushed into the receiving opening (56) by contact with the inside of the receiving opening (56). Gas engine spark plug according to one of the preceding claims, characterized in that a chamber (28) filled with dielectric coolant is provided inside the gas engine spark plug, through which a power supply line (24) preferably runs. Gas engine spark plug after Claim 12 , characterized in that the chamber (28) filled with dielectric coolant has an inlet (36) and an outlet (38) and coolant flows through it. Gas engine spark plug according to one of the preceding claims, characterized in that a tubular housing (10) defines the gas engine spark plug on the outside and has an overpressure line (92) through which gas from the antechamber (14) passes a seal (61, 66) downstream can flow into the open air.

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