APPARATUS FOR DETECTING LEAKAGE OF FLUID IN AUTOMOBILE FUEL INJECTORS

Description

TECHNICAL FIELD

[0001] The present invention relates to an apparatus for detecting leakage of fluid in automobile fuel injectors (GB-A 2 431 715).

[0002] In particular, the present invention relates to an apparatus for detecting leakage of fluid in an injector supplied with a test fluid under pressure and provided with an outlet hole, which is obtained in correspondence with an end face of the injector, and cooperates with a shutter that is movable between an open position and a closed position of said outlet hole.

[0003] The apparatus comprises a light source to irradiate the end face of the injector using light radiation in a given wavelength and a sensing device to measure the intensity of the light radiation reflected by said end face.

[0004] Since the intensity of the light radiation reflected by the end face of the injector varies according to the amount of test fluid that is present on said end face, the output signal of the sensing device is related to the leakage of test fluid from the injector.

BACKGROUND ART

[0005] The known apparatus of the kind described above have several drawbacks mainly deriving from the fact that said apparatus are relatively imprecise since the intensity of the light radiation measured by the sensing device varies with changes in certain uncontrollable parameters during the test such as, for instance, the surface finish of the end face of the injector or interference with the ambient light.

DISCLOSURE OF INVENTION

[0006] It is an object of the present invention to provide an apparatus for detecting leakage of fluid in automobile fuel injectors that overcomes the drawbacks described above and is simple and inexpensive to produce.

[0007] According to the present invention there is provided an apparatus for detecting leakage of fluid in automobile fuel injectors as set forth in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present invention will now be described with reference to the attached drawings, illustrating a nonlimiting embodiment thereof, in which:

figure 1 is a schematic exploded perspective view of a preferred embodiment of the apparatus according to the present invention;

figure 2 is a perspective view of a detail of the apparatus of figure 1; and

figure 3 is a cross-section of the detail of figure 2.

BEST MODE FOR CARRYING OUT THE INVENTION

[0009] With reference to figure 1, number 1 indicates, as a whole, an apparatus for sensing leakages of fluid in an automobile fuel injector 2 of a known type (figure 2), which is connected to a device (not illustrated) for supplying a test fluid under pressure capable of absorbing, in the same way as the fuel used in automobiles, light radiation in the ultraviolet light wavelength range, and is provided with an outlet hole (not illustrated) which cooperates with a shutter (not illustrated) movable between an open position and a closed position of said outlet hole (not illustrated).

[0010] According to that illustrated in figures 2 and 3, the apparatus 1 comprises a detector cell 3 comprising, in turn, a plate 4 that is substantially parallelepiped in shape having an upper wall 5 and a lower wall 6 substantially parallel to one another, two side walls 7 substantially parallel to one another and orthogonal to the walls 5 and 6, and two side walls 8 substantially parallel to one another and orthogonal to the walls 5, 6 and 7.

[0011] The plate 4 is also provided with a hole 9, which has a longitudinal axis 10 substantially orthogonal to the walls 7, extends through the plate 4, and comprises a narrowed central portion 11, two widened end portions 12, arranged on opposite sides of the portion 11, and which open outwardly in correspondence with the walls 7, and two intermediate portions 13 connecting the portion 11 to the portions 12.

[0012] The portion 11 is axially closed by means of two closing elements 14, which are transparent to light radiation in the ultraviolet light wavelength range, are mounted inside the portions 13 transversely to the axis 10, are made, preferably, of quartz and define, with said portion 11, a chamber 15 for containing a contrast fluid, preferably a hydrocarbon, which is different to the test fluid contained in the injector 2.

[0013] In particular, the contrast fluid and the test fluid have different capacities for absorbing the light radiation in the ultraviolet light wavelength range. In the specific case, the contrast fluid is substantially transparent, and in any case more transparent than the test fluid, to light radiation in the ultraviolet light wavelength range.

[0014] The chamber 15 is provided with a feed valve 16, which is mounted in a seat 17 obtained in one of the walls 8 transversely to the axis 10, and communicates with the chamber 15 to feed the contrast fluid into the chamber 15, and an outlet valve 18, which is mounted in a seat 19 obtained in the other wall 8 transversely to the axis 10, and communicates with the chamber 15 to discharge the contrast fluid to the outside of said chamber 15.

[0015] Each portion 12 internally houses a sleeve 20, which is mounted inside the portion 12 coaxially to the axis 10, and supports a collimating lens (figure 1) mounted inside said sleeve 20.

[0016] The plate 4 is also provided with a further hole 22, which has a longitudinal axis 23 substantially transversal to the axis 10 and orthogonal to the walls 5 and 6, is limited internally by a stepped face 24 tapered towards the axis 10, opens outwardly in correspondence with the upper wall 5, and is connected to an intermediate point of the chamber 15.

[0017] The hole 22 internally houses a cylindrical sleeve 25, which is mounted coaxially to the axis 23, and supports a lower end of the injector 2 to enable said outlet hole (not illustrated) of said injector 2 to communicate hydraulically with the chamber 15.

[0018] With reference to figure 1, the apparatus 1 also comprises a light source 26, which is connected to one of the lenses 21 (hereinafter indicated by 21a) by means of an optical fiber 27, and is suitable to deliver light radiation, preferably pulsed, in the ultraviolet light wavelength range, to the lens 21a, and, thus, to the chamber 15.

[0019] The source 26 is connected to the optical fiber 27 by means of the interposition of a filtering device 28 suitable to block the light radiation in the infrared light wavelength range and thus only allow the light radiation in the ultraviolet light wavelength range and visible light to travel along the optical fiber 27.

[0020] The apparatus 1 also comprises a sensing device 29, which is connected to the other lens 21 (hereinafter indicated by 21b) by means of an optical fiber 30, is suitable to measure the intensity of the light radiation leaving the chamber 15, and, in the specific case, comprises an optical sensor normally referred to as a photodetector.

[0021] The device 29 is connected to the optical fiber 30 by means of the interposition of a reducing device 31 arranged between the optical fiber 30 and the device 29 to reduce the intensity of the light radiation supplied to the device 29 and a filtering device 32 arranged between the devices 29 and 31 to block the light radiation in the visible light wavelength range and thus only allow the light radiation in the ultraviolet light range to reach the device 29.

[0022] In use, the light radiation emitted by the source 26 is supplied in the first instance through the filtering device 28, then along the optical fiber 27 and finally through the collimating lens 21a in order to pass through the containment chamber 15 with a substantially cylindrical shape.

[0023] The light radiation leaving the containment chamber 15 is then supplied in the first instance through the collimating lens 21b in order to alter its cylindrical shape, then along the optical fiber 30, through the reducing device 31 and the filtering device 32, and finally to the sensing device 29, which sends an output signal proportional to the intensity of said light radiation.

[0024] The intensity of the light radiation measured by the device 29, and, thus, the output signal of said device 29 vary according to the contents of the chamber 15. Thus, in case of leakages from the injector 2, the presence of test fluid in the chamber 15 determines a partial absorption of the light radiation supplied through said chamber 15 and, thus, a different output signal of the device 29.

[0025] The output signals of the device 29 can be used to plot a characteristic curve in which each output signal of the device 29 corresponds to a given quantity of test fluid in the chamber 15 and, thus, a given leakage from the injector 2, and to calculate the leakages from the injector 2 over a given period of time and, thus, the mean leakage from said injector 2.

[0026] According to an alternative embodiment that is not illustrated, the apparatus 1 comprises a sensing device completely identical to the sensing device 29 and a light dividing device arranged between the light source 26 and the filtering device 28 to selectively supply the light radiation emitted by the light source 26 partly to the filtering device 28 and partly to said sensing device in order to measure the intensity of the light radiation emitted by said light source 26.

Claims

1. Apparatus for detecting leakage of fluid in automobile fuel injectors (2), the apparatus comprising a chamber (15), which contains a contrast fluid, and is connected to an injector (2) to which a test fluid different to the contrast fluid is delivered under pressure; a light source (26) to supply light radiation through the containment chamber (15); and a sensing device (29) to measure the intensity of the light radiation upon leaving said chamber (15).

2. Apparatus according to claim 1, wherein the contrast fluid and the test fluid have different capacities for absorbing the light radiation emitted by the light source (26).

3. Apparatus according to claim 1 or 2, wherein the light source (26) is suitable to emit light radiation mainly comprised in the ultraviolet wavelength range.

4. Apparatus according to any one of the previous claims, wherein the light source (26) is suitable to emit a pulsed light radiation.

5. Apparatus according to any one of the previous claims, wherein the test fluid has a given capacity to absorb light radiation in the ultraviolet wavelength range.

6. Apparatus according to any one of the previous claims, wherein the contrast fluid is a fluid that is substantially transparent to light radiation in the ultraviolet wavelength range.

7. Apparatus according to any one of the previous claims, wherein the sensing device (29) comprises an optical element (29) suitable to send an output signal proportional to the intensity of the light radiation leaving the containment chamber (15).

8. Apparatus according to any one of the previous claims and also comprising a first optical fiber transmission device (27) to optically connect the light source (26) and the containment chamber (15) to one another.

9. Apparatus according to any one of the previous claims and also comprising a second optical fiber transmission device (30) to optically connect the containment chamber (15) and the sensing device (29) to one another.

10. Apparatus according to any one of the previous claims and also comprising a first collimating lens (21a) to give a given shape to the light radiation entering the containment chamber (15).

11. Apparatus according to any one of the previous claims and also comprising a second collimating lens (21b) to give a given shape to the light radiation leaving the containment chamber (15).

12. Apparatus according to any one of the previous claims and also comprising a first filtering device (28) arranged between the light source (26) and the containment chamber (15) to block the light radiation in the infrared light wavelength range.

13. Apparatus according to claim 12 and also comprising a further sensing device and a light dividing device arranged between the light source (26) and the first filtering device (28) to selectively supply the light radiation emitted by the light source (26) in part to the first filtering device (28) and in part to said further sensing device in order to measure the intensity of the light radiation emitted by said light source (26).

14. Apparatus according to any one of the previous claims and also comprising a reducing device (31) to reduce the intensity of the light radiation leaving the containment chamber (15) and entering the sensing device (29).

15. Apparatus according to any one of the previous claims and also comprising a second filtering device (32) arranged between the containment chamber (15) and the sensing device (29) to block the light radiation in the visible light wavelength range.

Ansprüche

1. Vorrichtung zum Detektieren eines Fluidlecks in Kraftfahrzeug-Kraftstoffeinspritzeinrichtungen (2), wobei die Vorrichtung eine Kammer (15), die ein Kontrastfluid enthält und mit einer Einspritzeinrichtung (2) verbunden ist, an die ein von dem Kontrastfluid verschiedenes Testfluid unter Druck geliefert wird; eine Lichtquelle (26), um durch die Behälterkammer (15) Lichtstrahlung zuzuführen; und eine Erfassungsvorrichtung (29), um die Intensität der Lichtstrahlung beim Verlassen der Kammer (15) zu messen, umfasst.

2. Vorrichtung nach Anspruch 1, wobei das Kontrastfluid und das Testfluid unterschiedliche Kapazitäten für die Absorption der von der Lichtquelle (26) emittierten Lichtstrahlung haben.

3. Vorrichtung nach Anspruch 1 oder 2, wobei die Lichtquelle (26) geeignet ist, Lichtstrahlung zu emittieren, die hauptsächlich im Ultraviolettwellenlängenbereich enthalten ist.

4. Vorrichtung nach einem der vorhergehenden Ansprüche, wobei die Lichtquelle (26) gepulste Lichtstrahlung emittieren kann.

5. Vorrichtung nach einem der vorhergehenden Ansprüche, wobei das Testfluid eine gegebene Kapazität hat, um Lichtstrahlung im Ultraviolettwellenlängenbereich zu absorbieren.

6. Vorrichtung nach einem der vorhergehenden Ansprüche, wobei das Kontrastfluid ein Fluid ist, das für Lichtstrahlung im Ultraviolettwellenlängenbereich im Wesentlichen durchlässig ist.

7. Vorrichtung nach einem der vorhergehenden Ansprüche, wobei die Erfassungsvorrichtung (29) ein optisches Element (29) umfasst, das ein zu der Intensität der die Behälterkammer (15) verlassenden Lichtstrahlung proportionales Ausgangssignal senden kann.

8. Vorrichtung nach einem der vorhergehenden Ansprüche, die außerdem eine erste Lichtleitfaser-Übertragungsvorrichtung (27) umfasst, um die Lichtquelle (26) und die Behälterkammer (15) optisch miteinander zu verbinden.

9. Vorrichtung nach einem der vorhergehenden Ansprüche, die außerdem eine zweite Lichtleitfaser-Übertragungsvorrichtung (30) umfasst, um die Behälterkammer (15) und die Erfassungsvorrichtung (29) optisch miteinander zu verbinden.

10. Vorrichtung nach einem der vorhergehenden Ansprüche, die außerdem eine erste Kollimatorlinse (21a) umfasst, um der in die Behälterkammer (15) eintretenden Lichtstrahlung eine gegebene Form zu verleihen.

11. Vorrichtung nach einem der vorhergehenden Ansprüche, die außerdem eine zweite Kollimatorlinse (21 b) umfasst, um der die Behälterkammer (15) verlassenden Lichtstrahlung eine gegebene Form zu verleihen.

12. Vorrichtung nach einem der vorhergehenden Ansprüche, die außerdem eine erste Filtervorrichtung (28) umfasst, die zwischen der Lichtquelle (26) und der Behälterkammer (15) angeordnet ist, um die Lichtstrahlung im Infrarotlichtwellenlängenbereich zu blockieren.

13. Vorrichtung nach Anspruch 12, die außerdem eine weitere Erfassungsvorrichtung und eine Lichtteilungsvorrichtung, die zwischen der Lichtquelle (26) und der ersten Filtervorrichtung (28) angeordnet sind, umfasst, um die von der Lichtquelle (26) emittierte Lichtstrahlung teilweise der ersten Filtervorrichtung (28) und teilweise der weiteren Erfassungsvorrichtung zuzuführen, um die Intensität der von der Lichtquelle (26) emittierten Lichtstrahlung zu messen.

14. Vorrichtung nach einem der vorhergehenden Ansprüche, die außerdem eine Reduzierungsvorrichtung (31) umfasst, um die Intensität der die Behälterkammer (15) verlassenden und in die Erfassungsvorrichtung (29) eintretenden Lichtstrahlung zu reduzieren.

15. Vorrichtung nach einem der vorhergehenden Ansprüche, die außerdem eine zweite Filtervorrichtung (32) umfasst, die zwischen der Behälterkammer (15) und der Erfassungsvorrichtung (29) angeordnet ist, um die Lichtstrahlung im Wellenlängenbereich des sichtbaren Lichts zu blockieren.

Revendications

1. Appareil permettant de détecter une fuite de fluide dans des injecteurs (2) de carburant d'un véhicule automobile, l'appareil comprenant une chambre (15), qui contient un fluide de contraste, et est reliée à un injecteur (2) auquel un fluide de test différent du fluide de contraste est délivré sous pression; une source lumineuse (26) destinée à fournir un rayonnement lumineux à travers la chambre de confinement (15) ; et un dispositif de détection (29) destiné à mesurer l'intensité du rayonnement lumineux à sa sortie de ladite chambre (15).

2. Appareil selon la revendication 1, dans lequel le fluide de contraste et le fluide de test ont des capacités différentes pour absorber le rayonnement lumineux émis par la source lumineuse (26).

3. Appareil selon les revendications 1 ou 2, dans lequel la source lumineuse (26) est adaptée pour émettre un rayonnement lumineux principalement compris dans la plage de longueur d'onde des UV.

4. Appareil selon l'une quelconque des revendications précédentes, dans lequel la source lumineuse (26) est adaptée pour émettre un rayonnement de lumière pulsée.

5. Appareil selon l'une des revendications précédentes, dans lequel le fluide de test a une capacité donnée pour absorber un rayonnement lumineux dans la plage de longueur d'onde des UV.

6. Appareil selon l'une quelconques des revendications précédentes, dans lequel le fluide de contraste est un fluide qui est essentiellement transparent au rayonnement lumineux dans la plage de longueur d'onde des UV.

7. Appareil selon l'une quelconques des revendications précédentes, dans lequel le dispositif de détection (29) comporte un élément optique (29) adapté pour envoyer un signal de sortie proportionnel à l'intensité du rayonnement lumineux sortant de la chambre de confinement (15).

8. Appareil selon l'une quelconques des revendications précédentes et comprenant en outre un premier dispositif de transmission (27) par fibre optique pour relier de manière optique la source lumineuse (26) et la chambre de confinement (15) l'une à l'autre.

9. Appareil selon l'une quelconques des revendications précédentes et comprenant en outre un deuxième dispositif de transmission (30) par fibre optique pour relier de manière optique la chambre de confinement (15) et le dispositif de détection (29) l'un à l'autre.

10. Appareil selon l'une des revendications précédentes et comprenant également une première électrode de collimation (21a) pour donner une forme donnée au rayonnement lumineux pénétrant dans la chambre de confinement (15).

11. Appareil selon l'une des revendications précédentes et comprenant également une deuxième électrode de collimation (21b) pour donner une forme donnée au rayonnement lumineux sortant de la chambre de confinement (15).

12. Appareil selon l'une des revendications précédentes et comprenant en outre un premier dispositif de filtrage (28) agencé entre la source lumineuse (26) et la chambre de confinement (15) pour bloquer le rayonnement lumineux dans la plage de longueur d'onde de lumière infrarouge.

13. Appareil selon la revendication 12 et comportant également un dispositif de détection supplémentaire et un dispositif de division de lumière agencés entre la source lumineuse (26) et le premier dispositif de filtrage (28) pour alimenter au choix le rayonnement lumineux émis par la source lumineuse (26) au premier dispositif de filtrage (28) en partie et audit dispositif de détection additionnel en partie afin de mesurer l'intensité du rayonnement lumineux émis par ladite source lumineuse (26).

14. Appareil selon l'une des revendications précédentes et comprenant également un dispositif de réduction (31) pour réduire l'intensité du rayonnement lumineux sortant de la chambre de confinement (15) et pénétrant dans le dispositif de détection (29).

15. Appareil selon l'une des revendications précédentes et comprenant en outre un deuxième dispositif de filtrage (32) agencé entre la chambre de confinement (15) et le dispositif de détection (29) pour bloquer le rayonnement lumineux dans la plage de longueur d'onde de lumière dans le domaine visible.

Drawing