DE102017216049A1 - Electromagnetically actuated gas valve and method for detecting gas leakage - Google Patents

Abstract

The invention relates to an electromagnetically operable gas valve (1) for dosing a gaseous fuel into a suction pipe (2) of an engine, in particular a gas or diesel gas engine, comprising a directly or indirectly via an adapter piece (3) with the suction pipe (3). 2) connectable housing (4) in which a valve plate (5) and a relative to the valve plate (5) movable valve disc (6) for releasing and closing at least one flow opening (7) of the valve plate (5) are added. According to the invention, at least one sensor (8, 9) is integrated in the housing (4) or in the adapter piece (3) in the region of an outlet (10) for detecting gas leakage.
Furthermore, the invention relates to a method for detecting a gas leakage in the region of an outlet (10) of an electromagnetically actuated gas valve (1).

Description

The invention relates to an electromagnetically operable gas valve for metering a gaseous fuel into a suction pipe of an engine, in particular a gas or diesel gas engine, having the features of the preamble of claim 1. Furthermore, the invention relates to a method for detecting a gas leakage in the area an outlet of an electromagnetically actuable gas valve.

State of the art

Electromagnetically actuated gas valves for injecting gaseous fuels into a suction pipe of a gas engine are already known from the prior art. Exemplary is on the DE 10 2013 212 191 A1 which discloses a method and apparatus for injecting a gaseous medium.

Gas valves of this type are usually designed as normally closed valves. This means that when the solenoid is de-energized, the gas valve is closed. When energizing the electromagnet, a movable valve plate is raised, so that one or more flow openings are released. To close the energization of the electromagnet is terminated, so that springs return the valve disc, wherein the valve plate passes for sealing engagement with a fixed valve seat member. Ideally, then the gas valve is sealed, so that no gas enters the suction pipe by way of leakage.

Since the gas valve is subject to wear over the service life, this can lead to leaks in the area of the sealing surfaces, so that there is a gas leak. Furthermore, passing between the sealing surfaces particles can lead to an undesirable gas leakage. To prevent damage to the engine due to excessive gas leakage into the intake manifold, therefore, the leakage is monitored.

A known possibility for leak detection is the pressure monitoring in the gas supply line. In the normal case, however, the gas supply supplies several gas valves, so that it is impossible with this method to determine which gas valve is leaking. In addition, no small amounts of leakage can be detected in this way. If the tightness of a single gas valve is to be checked, it must be removed and transported to an external leak test bench. There, then, for example by means of the pressure drop method, the tightness of the gas valve checked or the leakage amount can be determined.

Based on the above-mentioned prior art, the present invention seeks to provide an apparatus and a method for monitoring the gas leakage of a gas valve during operation to detect leakage early and possibly take measures to protect the engine.

To solve the problem, the gas valve is proposed with the features of claim 1. Furthermore, the method for detecting a gas leakage with the features of claim 8 is given. Advantageous developments of the invention can be found in the respective subclaims.

Disclosure of the invention

The electromagnetically actuated gas valve proposed for metering in a gaseous fuel into a suction pipe of an engine, in particular a gas or diesel gas engine, comprises a housing which can be connected directly or indirectly to the intake manifold via an adapter piece, in which a valve plate and one opposite the valve plate movable valve plate for releasing and closing at least one flow opening of the valve plate are added. According to the invention, at least one sensor in the region of an outlet is integrated in the housing or in the adapter piece for the detection of a gas leakage.

By means of the at least one sensor arranged in the region of the outlet, it is possible to monitor, with the gas valve being closed, whether gas is escaping. The escape of gas suggests an undesirable leakage so that it can be detected early. Furthermore, the leakage can be assigned to a specific gas valve, since the monitoring takes place at the gas valve itself, during operation.

According to a preferred embodiment of the invention, the at least one sensor is an ultrasonic sensor. That is, at least one ultrasonic sensor is provided, which transmits and / or receives an ultrasonic signal, the signal propagation time allowing conclusions to be drawn about the surrounding medium. Because gaseous fuels, in particular natural gas, have a lower density than air, so that in the gaseous fuel or in a natural gas-air mixture, the ultrasonic signal propagates faster than in pure air. The speed of sound increases with increasing natural gas content.

In addition, the at least one sensor may also be a tuning fork sensor, which - based on the different density of the gaseous fuel to air - the physical Effect uses that the density of a gas affects the resonant frequency.

This means that at least one sensor must be integrated in the housing or in the adapter piece of the gas valve, which detects a dependent on the density of the surrounding gaseous medium size.

To evaluate the sensor signal, the at least one sensor can be connected to its own evaluation electronics or to an already existing engine control unit (ECU). The evaluation then takes place automatically. Preferably, a threshold is defined for the automatic evaluation, from which leakage is considered critical. If this threshold is exceeded, for example, an emergency stop of the engine can be arranged to prevent engine damage. In the case of a leakage below the threshold, information can be sent to an operator or to a supervisor that a service is about to be carried out in the near future. The communication between the at least one sensor and the transmitter or the engine control unit can be wired or wireless.

Preferably, the at least one sensor is inserted into a bore of the housing or of the adapter piece connected to the outlet. The sensor can thus be arranged in a simple manner in the region of the outlet of the gas valve.

Because the outlet is the area that needs to be monitored. Preferably, the sensor is screwed or pressed into the bore of the housing or the adapter piece, so that it is easy to remove if necessary, for example, to replace the sensor. The sensor can thus have an external thread, which is designed corresponding to an internal thread of the bore. Alternatively, the sensor may have a press interference with the diameter of the bore to make a press fit.

If the at least one sensor is an ultrasonic sensor, it is proposed that a first sensor serving as a transmitter and a second sensor serving as a receiver face each other at the outlet of the gas valve. This ensures that an ultrasound signal emitted by the first sensor is received by the second sensor, the signal propagation time from the transmitter to the receiver providing information about a leakage quantity present in the outlet of the gas valve. In order to carry out the required evaluation, preferably the second sensor serving as a receiver is connected to an evaluation device.

According to an alternative embodiment, only a single sensor is provided, which also serves as transmitter and receiver. In this case, the sensor faces a reflective wall surface at the outlet of the gas valve. The ultrasonic signal emitted by the sensor is then reflected from the opposite wall surface and received by the same sensor. The signal then returns twice the way. It proves to be advantageous that only one sensor is required, thus reducing manufacturing and assembly costs.

The outlet of the gas valve is preferably formed by a central opening of the housing and / or by a central recess of the adapter piece. The cross-sectional shape of the opening or the recess is basically arbitrary, but must be sized large enough to meter the gaseous fuel into the intake manifold can. To form the opening, for example, the housing may be at least partially hollow cylinder-shaped. The adapter piece can be designed in particular plate or ring.

Advantageously, two sensors or a sensor and a reflective wall surface are located diametrically opposite one another at the outlet. In this case, the ultrasonic signal must pass through the entire diameter or the entire width of the outlet, at least once. In this way it is largely ensured that in case of leakage of the gas valve, the leakage amount is also detected.

To solve the object mentioned above, a method for detecting a gas leakage in the region of an outlet of an electromagnetically actuable gas valve for metering a gaseous fuel into a suction pipe of an engine, in particular a gas or diesel gas engine is also proposed. According to the invention, at least one sensor is used in the method, which is integrated in the region of the outlet in a housing or in an adapter piece for connecting the housing to the suction tube. Accordingly, the outlet region of the gas valve is monitored by means of the at least one sensor, since the gaseous fuel reaches the intake pipe via the outlet.

Preferably, the at least one sensor provides information about the gas composition in the region of the outlet of the gas valve, so that it can be concluded that leakage. Further preferably, the at least one sensor detects a dependent on the density of the surrounding gaseous medium size, since the density of the gaseous fuel, in particular, when the gaseous fuel is natural gas, is less than that of air.

Therefore, an ultrasonic sensor or a tuning fork sensor is preferably used as the sensor. The ultrasonic sensor emits an ultrasonic signal, the transit time of which changes as a function of the density of the surrounding medium. Accordingly, the gas composition in the region of the outlet of the gas valve can be concluded over the duration of the signal. The tuning fork sensor uses the physical effect that the density of the gas or the gas composition influences the resonance frequency.

• 1 einen Querschnitt durch ein Adapterstück eines erfindungsgemäßen Gasventils,
• 2 einen Längsschnitt durch das Adapterstück der 1,
• 3 einen schematischen Längsschnitt durch ein Gasventil, das an einem Saugrohr angeordnet ist, und
• 4 ein Diagramm zur Darstellung der Abhängigkeit der Schallgeschwindigkeit vom Erdgasanteil in einem Erdgas-Luft-Gemisch.

The gas valve according to the invention and the method according to the invention are explained in more detail below with reference to the accompanying drawings. The drawings show:

• 1 a cross section through an adapter piece of a gas valve according to the invention,
• 2 a longitudinal section through the adapter piece of 1 .
• 3 a schematic longitudinal section through a gas valve, which is arranged on a suction pipe, and
• 4 a diagram showing the dependence of the speed of sound of natural gas in a natural gas-air mixture.

Detailed description of the figures

The 1 and 2 is an adapter piece 3 a gas valve according to the invention 1 to take that of the connection of the gas valve 1 with a suction tube (not shown) is used. In the adapter piece 3 are a first sensor serving as a transmitter 8th and a second sensor serving as a receiver 9 integrated, whereby the two sensors 8th . 9 at a central recess 14 of the adapter piece 3 lying diametrically opposite. The central recess 14 forms an outlet 10 through which a gaseous fuel, preferably natural gas, into the intake manifold 2 is blown when the gas valve 1 is open. Is the gas valve 1 closed, the outlet fills up 10 with air from the suction pipe 2 ,

The gas composition in the area of the outlet 10 should therefore with the gas valve closed 1 contain no or only small amounts of gaseous fuel. If this is not the case, this indicates a leak of the gas valve 1 out. Whether there is an impermissibly high leakage quantity in the area of the outlet 10 of the gas valve 1 can, by means of the two sensors 8th . 9 be recorded. Because the two sensors 8th . 9 together form an ultrasonic sensor, wherein the first sensor 8th emits an ultrasonic signal through the second sensor 9 received and an evaluation device (not shown) is transmitted. The transit time of the ultrasonic signal provides information about the gas composition, since the transit time is dependent on the density of the gaseous medium and the density is different depending on the proportion of the gaseous fuel.

In the 4 exemplified is the dependence of the duration of an ultrasonic signal in a natural gas-air mixture with increasing natural gas content. Since the density of natural gas is lower than that of air, the speed of sound increases as more natural gas is contained in the gas mixture.

In contrast to the representation of the 1 and 2 , the ultrasonic sensor can also be controlled by a single sensor 8th be formed, which then serves both as sender and receiver. In this case, the sensor must 8th no second sensor 9 but a reflective wall surface at the outlet 10 lie opposite (not shown).

To the sensor 8th or the sensors 8th . 9 If necessary, they are preferably drilled in holes 11 . 12 of the adapter piece 3 screwed or pressed. That's how the sensors are 8th . 9 not only easy to assemble, but also easy to disassemble. It can in the adapter plate 3 be designed as sensor seats suitable holes in serving as a placeholder screws 16 can be used to close the holes. To ensure a gas-tight closing of the holes, between the screws 16 and the adapter piece 3 seals 15 be inserted. The same applies to the holes 11 . 12 into which the sensors 8th . 9 are screwed in.

Of the 3 is a gas valve according to the invention 1 to take that directly over a housing 4 with a suction pipe 2 connected is. That means that no adapter piece 3 for connection to the suction pipe 2 is provided.

In the case 4 are a valve plate 5 and one opposite the valve plate 5 movable valve disk 6 for releasing and closing at least one in the valve plate 5 trained flow opening 7 added. The gas valve 1 is flowed through axially (see arrows 17 ), with a front opening 13 the hollow cylindrical housing 4 an outlet 10 forms over which the gaseous fuel, preferably natural gas, in the intake manifold 2 arrives. There, the gaseous fuel mixes with air that is supplied from outside (see arrow 18 ).

In the in the 3 illustrated gas valve 1 is the sensor 8th or are the sensors 8th . 9 for detecting gas leakage into the housing 4 integrated. The mode of action corresponds to that previously in connection with the adapter piece 3 of the 1 and 2 described mode of action, so that reference is made to this part of the description.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102013212191 A1 [0002]

Claims (9)

Electromagnetic actuated gas valve (1) for dosing a gaseous fuel in a suction pipe (2) of an engine, in particular a gas or diesel gas engine comprising a directly or indirectly via an adapter piece (3) with the suction pipe (2) connectable housing (4), in which a valve plate (5) and a relative to the valve plate (5) movable valve disc (6) for releasing and closing at least one flow opening (7) of the valve plate (5) are accommodated, characterized by at least one sensor (8, 9), which is integrated to detect a gas leakage in the region of an outlet (10) in the housing (4) or in the adapter piece (3). Gas valve (1) after Claim 1 , characterized in that the at least one sensor (8, 9) is an ultrasonic sensor or a tuning fork sensor. Gas valve (1) after Claim 1 or 2 , Is preferably screwed or pressed characterized in that the at least one sensor (8, 9) related to a to the outlet (10) bore (11, 12) of the housing (4) or the adapter piece (3). Gas valve (1) according to one of the preceding claims, characterized in that serving as a transmitter first sensor (8) and serving as a receiver second sensor (9) are located opposite to the outlet (10). Gas valve (1) after one of Claims 1 to 3 , characterized in that a single serving as a transmitter and receiver sensor (8) is provided, which at the outlet (10) is located opposite a reflective wall surface. Gas valve (1) according to one of the preceding claims, characterized in that the outlet (10) through a central opening (13) of the housing (4) and / or through a central recess (14) of the adapter piece (3) is formed. Gas valve (1) according to any one of the preceding claims, characterized in that two sensors (8, 9) or a sensor (8) and a reflective wall surface at the outlet (10) are diametrically opposite. Method for detecting a gas leak in the region of an outlet (10) of an electromagnetically operable gas valve (1) for metering a gaseous fuel into a suction pipe (2) of an engine, in particular a gas or diesel gas engine, characterized in that at least one Sensor (8, 9) is used, which is integrated in the region of the outlet (10) in a housing (4) or in an adapter piece (3) for connecting the housing (4) with the suction tube (2). Method according to Claim 8 , characterized in that an ultrasonic sensor or a tuning fork sensor is used.

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