DE8104762U1 - SENSOR ARRANGEMENT - Google Patents

Description

R. 6815

9.2.1981 Wt / Hm

ROBERT BOSCH GMBH, 7000 STUTTGART 1

Sensor arrangement
State of the art

The invention is based on a sensor arrangement according to the preamble of the main claim.

It is known that the combustion processes taking place in the combustion chamber of an internal combustion engine during operation
of the internal combustion engine according to different points of view while recording different physical parameters. This includes, for example, the detection of the temporal and spatial spread of the
Combustion process, the detection of the ignition point, the detection of injection processes and the measurement of irregular combustion.

L- ^: .r.;! ° O. 1 68 1

One of these irregular burns is what is known as "knocking", which occurs under various conditions in internal combustion engines Working conditions occurs. This is understood to mean sound-frequency vibrations of the compressed fuel-air mixture, triggered by a shock wave. During these oscillations, the heat transfer is on The piston and cylinder walls of the internal combustion engine are strong elevated. This has a harmful thermal overload of these surfaces as a result, so that the knocking in principle is to be avoided. On the other hand, since one strives to use the available work area to utilize the internal combustion engine as much as possible, it is necessary to provide means which indicate the knocking early and reliably, in order to be able to do this in this way To be able to control the internal combustion engine, in which the internal combustion engine is always just below the Knock limit is operated.

A large number of sensors have become known or have been proposed for this purpose. So is for example from DE-OS 28 09 969 a sensor is known in which with With the help of a piezoelectric vibrating element as a flexural vibrator, a resonant system is formed that the Able to indicate knocking of the internal combustion engine. A The disadvantage of this known arrangement is that the mechanical mode of operation is not particularly free from malfunctions in the event of strong bumps in the motor vehicle.

On the other hand, it is known to observe the combustion process in an internal combustion engine by optical means and to eat. For example, in the Motortechnische Zeitschrift, 39 (1978), page 385, a spectrometric Measurement method for investigating the combustion in diesel engines described in which a quartz window in the combustion chamber wall is attached, through which a spectrometric Observation of the combustion processes possible

• ■

• · · 4

■ · ■ ·

I ■

| s is. It is also known from DE-OS 27 01 777, a

! ', ■ to arrange a light-sensitive sensor in the combustion chamber

; ' hit by a laser beam that previously hit the mouth of a

t has affected the injector in this way

| 5 to measure injection time on injection valves. From the Rev.

p. Tech. Automobile. 1979, pages 89, 90 is still an optical one

k analyzer known to take the place of spark plugs

1 of an internal combustion engine is screwed to a

| f calorimetric analysis of the fuel-air mixture

E to perform. Finally, on a working group

I session "Hydrocarbon Emissions" of the research

if * 3? agreement for combustion engines eV on 10.10.79 in ·

g Aachen "explained an arrangement in Spicher's presentation

I, in which the flame spread in the combustion chamber of the

£ Internal combustion engine with the help of optical fibers that are in

bi the cylinder wall are screwed in and downstream.

l "teten photodiodes is detected.

A sensor arrangement is also proposed

J> Yorden, at least with her. _

a known optical “pick-up in the combustion chamber” is used, preferably a glass rod or a fiber optic cable, the optical pick-up

! "\ either integrated into the spark plug, to an antechamber

j> connected or inserted into the cylinder head gasket

i will be.

Since such optical combustion chamber sensors get dirty relatively quickly on their side facing the combustion chamber, there is an interest in designing such sensor arrangements so that the windows as possible can be exchanged quickly and easily.

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Advantages of the invention

The sensor arrangement according to the invention with the characteristic Features of the main claim has the advantage that a faster and more convenient replacement of the window part the sensor arrangement is possible. The window part is independent and detached from the downstream photoelectric pickup, so when replacing only the window part needs to be replaced.

The measures listed in the subclaims are advantageous developments of the main claim specified sensor arrangement possible. Thus, in an advantageous embodiment of the invention, the window part is inclined pushed in towards the surface of the combustion chamber wall on the side of the combustion chamber, so that through this inclined cut opposite a larger light incidence surface in a vertical arrangement is achieved.

drawing

Embodiments of the invention are shown in the drawing shown and explained in more detail in the following description. They show: FIG. 1 a first embodiment a sensor arrangement according to the invention; Figure 2 a second embodiment of a sensor arrangement according to the invention; FIG. 3 shows a window holder for use in an arrangement according to FIG. 1 or 2.

Description of the exemplary embodiments

In Figure 1, 1 denotes the combustion chamber of an internal combustion engine. The combustion chamber 1 is at the top by a

681

Combustion chamber wall 2, in FIG. 1 the cylinder head cover, "limited. A stepped bore 3 is let into the combustion chamber wall 2, ie a bore which has a larger diameter towards the outside and a smaller diameter at its end facing the combustion chamber 1. This forms in the step "hole 3 one shoulder h. A window part 5 is inserted from the outside into the stepped bore 3. The window part 5 has a diameter which corresponds approximately to the smaller diameter of the stepped bore 3 and at its lower end has a base 6, the diameter of which corresponds approximately to the larger diameter of the stepped bore 3. Accordingly, the base 6 rests on the shoulder k of the stepped bore 3, a seal 8 being arranged between the base 6 and shoulder k. On the side of the window part 5 facing away from the combustion chamber, a housing 11 is placed on the base 6. The housing 11 has a tubular part, the lower end of which is flanged so that a flat bearing surface on the base 6 is created. The tubular section of the housing 11 protrudes through a central bore of a nut 7, which has an external thread which engages in an internal thread that is arranged in the section with a larger diameter of the stepped bore 3. By screwing the nut 7 into the thread of the stepped bore 3, the housing 11 is fixed with an intermediate seal 9 on the base 6 of the window part 5 and thus also the window part 5 itself is fixed in the combustion chamber wall 2. The nut 7 has slots 10 into which a tool (not shown in the figure) engages in order to screw the nut 7 into the combustion chamber wall 2. A photo element 12 is also arranged in the housing 11. The window part 5 is finally related

«II Il

its rotational position to the axis of the stepped bore 3 by a Pin 13 fixed.

When the internal combustion engine is operating, light falls through it Window part 5 on the photo element 12, so that optical Observations of the combustion chamber are possible.

In the embodiment shown in Figure 2 of In the invention, the structural details are the same as in FIG. 1, only the axis of the window part 5 and thus the stepped bore 3 is shown in FIG Embodiment arranged perpendicular to the combustion chamber-side surface of the combustion chamber wall, while it is inclined in the embodiment shown in FIG. Depending on the local conditions and constructive Possibilities at the place of attachment of the sensor arrangement according to the invention can be one or the other Mounting method can be selected. However, the arrangement according to FIG. 1 has the advantage over that in FIG. that a correspondingly large light incidence surface is achieved through the inclined section of the window part 5.

Both exemplary embodiments have in common that the window part 5 can be replaced by simple means can without the photoelectric pickup assembly at the same time must be replaced, as is the case, for example, with combined sensors in which the photoelectric recording system and the combustion chamber window are arranged together in a spark plug-like housing. The easy interchangeability of the window part 5 without the need to exchange further elements is of particular advantage with sensors of this type, since the combustion chamber-side surface of the window part 5 during operation of the internal combustion engine by the

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Combustion gases dirty quickly.

In FIGS. 3a and b, a window holder is described as it can be used as an alternative to the holders shown in FIGS. 1 and 2. The window part 5 is in turn inserted into a stepped bore in the combustion chamber wall 2 and is through to the combustion chamber side
a seal 8 and to the side facing away from the combustion chamber
sealed by a seal 9. The mechanical holder takes over in this case a holding part 1 ^, with two sections, one of which engages with a first bore in the outwardly directed part of the stepped bore and of which the second has a further bore through which it can be attached to one in the Stud bolts 15 arranged on combustion chamber wall 2 can be screwed on by means of a nut 16. The housing 11 protrudes accordingly
the hole in the first section of the holding part "\ k in the upper part of the stepped hole.

Claims (3)

ff 9.02. 1981 Wt / Hm ROBERT BOSCH GMBH, 7000 STUTTGART 1 Expectations , 1. Sensor arrangement on an internal combustion engine for detecting i ' solution of physical parameters in the combustion chamber of the internal combustion engine, in which a window element is arranged in a combustion chamber wall, characterized in that in the combustion chamber [j: room wall (2) a stepped bore (3) with an external I the section of larger diameter and a k space (1) facing section of smaller diameter fe as well as an intermediate ring shoulder (h) I net is that in the stepped bore (3) a window part f '^; (5) is used, the one widened on the ι ring shoulder (k) resting base (6) that '<: on the base (6) from the outside a housing (11) with a ΓΙ 'Photo element (12) is in place and that the [;! The housing (11) through a hole in a nut (7) ^; . extends through with which the housing (11) on the base (6) and the base (6) on the ring shoulder (H) force- ; is conclusively pressed on. 68 15 2. Sensor arrangement on an internal combustion engine for detecting physical parameters in the combustion chamber of the internal combustion engine, in which a window element is arranged in a combustion chamber wall, characterized in that in the combustion chamber wall (2) a stepped bore (3) with an external gate of larger diameter and one to the combustion chamber (1) facing the smaller diameter cut and an intermediate annular shoulder {k) is arranged that in the stepped bore (3) a window part (5) is inserted, which has a widened base (6) resting on the annular shoulder (U), that a housing (11) with a photo element (12) is placed on the base (6) from the outside and that the housing (11) extends through a bore of a holding part (1U) which is connected to a further bore in the Combustion chamber wall (2) arranged stud bolts (15) is screwed so that the housing (11) is pressed onto the base (6) and the base (6) onto the annular shoulder (1 k) in a force-locking manner. 3. Sensor arrangement according to claim 1, characterized in that the axis of the window part (5) obliquely to the combustion chamber side Surface of the combustion chamber wall (2) is arranged.