FR2615613A1 - Automatic apparatus for evaluating the degree of polishing of a engine jacket - Google Patents

Abstract

Apparatus comprising a support table 4, a vertical carriage 6, a reducing motor 8, a device 10 for adjusting and centring the jacket 2, a device 12 for rapid fitting of the jacket, a device 14 for centring the interchangeable part 10, an optical sensor 16, two bundles of optical fibres 22, 24, an infrared diode 26 and a phototransistor 28. Application: Internal combustion engine tuning.

Description

AUTOMATIC APPARATUS FOR EVALUATING THE POLISHING DEGREE
A MOTOR SHIRT
The evaluation of the polishing of a jacket is important for the development of an internal combustion engine. The proper functioning of an engine requires correct lubrication of the jacket-segment assembly.

This lubrication is ensured by the reserve of oil accumulated in the machining grooves of the jacket.

The invention relates to an automatic device which allows the evaluation of the degree of polishing of the liners for - the development of the piston profile, - the verification of the aggressiveness of the different types of segment, - the selection of oils engines, - the selection of oil filtration systems, - and the estimation of the life of the cylinder unit and more particularly the bench / road test correlation.

Up to now, the evaluation of the polishing of a shirt has been carried out manually.

Scoring is done point by point using: a grid.

Each point is marked according to three levels - normal wear, - start of polishing, - glazing.

The percentage of surface at the start of polishing and of glazed surface is calculated, as well as a note "merit".

This rating has significant drawbacks. It turns out: - long, - unreliable (difference in lighting, eye strain from the cotator), - imprecise (the number of points observed being limited).

The invention aims to remedy these drawbacks. To this end, it offers an automatic device for evaluating the degree of polishing of a motor jacket, which comprises, according to an essential characteristic, a support table, a vertical carriage for ensuring the vertical displacement of an optical sensor, a geared motor not step by step to ensure the rotation of the liner, a device for calibrating and off-centering the liner, a device for rapid fitting of the liner, a device for centering this interchangeable part for calibration-centering of the liner, a sensor optical, two bundles of optical fibers; an infrared diode and a phototransistor.

Many significant advantages result from this - Rapid measurement.

- Reliability and repetitivity of the result (this rating is only interesting for making comparisons: comparison of two tests, one parameter having varied). Improved reliability and repeatability are 2 very important points.

- Clarity of results.

- Storage on computer support of the results (allows further processing, statistics for example).

Other features and advantages of the invention will emerge more clearly from the following description of a preferred embodiment, given by way of nonlimiting example, with reference to the accompanying drawings in which - Figure 1 shows a view in partial longitudinal section of an apparatus according to the invention, - and Figure 2 shows a schematic diagram for the implementation of this apparatus.

In accordance with FIG. 1, this automatic device for evaluating the degree of polishing of an engine liner 2 consists of the following constituent elements - A support table 4.

- A vertical carriage 6, equipped with a stepping motor 7 to ensure the vertical movement of a sensor 16.

- A step-by-step geared motor 8 to rotate the jacket 2.

- A device 10 for calibrating and centering the jacket 2.

This part is interchangeable for the different diameters of shirts. Its inner bore has a coating of two different materials giving two references of light reflection.

- A device 12 for rapid fitting of the jacket 2.

- A device 14 for centering the interchangeable part 10, equipped with a quick positioning system.

- An optical sensor 16, of which a shoe 18 keeps the fiber-jacket distance constant; the pressure is provided by a spring 20,. and an adjustable sleeve 21 allows adaptation to the different diameters of shirts.

- Two bundles of optical fibers 22, 24, one of which ensures the lighting of the jacket and the other conveys the reflected light. The fibers of the two bundles are randomly mixed on the sensor side.

- An infrared diode 26 as a light source.

- And a phototransistor 28 to convert variations in light into variations in current.

The operation of this device 'described below with reference to Figure 2 is based on a control of the polishing by measuring the reflected light.

- The jacket 2 is lit by the bundle of 22 optical fibers. The amount of reflected light, a function of the polishing and conveyed by the beam 24, is converted into voltage by a phototransistor 28 and then digitized by a digital analog converter 30.

- The signal is then processed by a microcomputer 32.

- An automatic calibration is made with each measurement. A standard piece 10 chrome on one half, painted in matt black on the other, gives two references (this same piece also ensures the centering of the shirt).

- Two stepping motors move the spot.

One 8 rotates the jacket 5 by 5, the other 7 increases the sensor 16 by 5 mm each turn.

Claims (2)

1 - Automatic device for evaluating the degree of polishing of a motor jacket (2), characterized in that it comprises - a support table (4), - a vertical carriage (6) equipped with a stepping motor ( 7) to ensure the vertical displacement of a sensor (16), - a step-by-step gearmotor (8) to ensure the rotation of the jacket (2), - a device (10) for calibrating and centering the jacket (2), - a device (12) for rapid fitting of the jacket, - a device (14) for centering the interchangeable part (10), - an optical sensor (16) with pad (18), spring ( 20) and adjustable sheath (21), - two bundles of optical fibers (22, 24) for respectively illuminating the jacket and conveying the reflected light, - an infrared diode (26), - and a phototransistor (28). 2 - Apparatus according to claim 1, caracterisE in that it is connected to an electronic unit (30) grouping a motor control and a digital analog converter, a microcomputer (32) and a printer (34).