DE3041226A1 - Piston oil-scraper ring - has internal electroplated chrome coating and external sprayed ferrous chrome one - Google Patents

Abstract

The piston oil-scraper ring comprises top and bottom parts with an expander acting between them. The top and bottom parts (5a,5b) are coated along their inner peripheries with chrome deposited by galvanising or electroplating (2a,2b), while a ferrous chrome coating is sprayed onto their outer peripheries (6a,6b). The surfaces of the expander (7) in contact with these parts have a coating formed by soft nitriding. One or more of the compression rings can have its face working against the cylinder wall sprayed with a ferrous chrome layer.

Description

Piston ring arrangement

The invention relates to a piston ring arrangement for internal combustion engines.

The between a piston and an inner wall of a cylinder of the Engine piston rings are generally of two types of rings divided, namely compression or. Compression rings to seal the work area and wiper rings, which are used to wipe off excess oil from the cylinder wall serve and also to prevent the penetration of bl into the work area. In automotive engines for example two or three compression rings and one or two oil control rings per piston applied in combination.

These piston rings must constantly radially outwards against the cylinder wall exciting, so it is extremely important to have an abrasion or a To prevent wear of the piston rings as much as possible, in particular in the area of the working or sliding surfaces of the piston rings.

One of the reasons for excessive oil consumption is wear and tear or the abrasion of the piston rings. The increase in oil consumption, in addition, too when using a highly leaded gasoline is increased, is based on the fact that the voltage worn piston rings decreases, so that their ability to scrape off excess oil is reduced considerably by the cylinder wall. It is also known that when using a multi-part blabstreifringes consisting of upper and lower ring bodies and an expansion body (spacer and expansion ring or helical expansion body) is composed, which serves to hold the upper and lower ring bodies against the To press cylinder wall, the greatest abrasion in the area of the inner and / or outer Peripheral surfaces of these two ring bodies takes place.

Proceeding from this, the invention is based on the object of a piston ring arrangement to be designed in such a way that an increase in fuel consumption due to wearing piston rings is largely avoided, even if a highly leaded gasoline is used will.

The piston ring arrangement according to the invention is used to solve this problem for a piston movable within a cylinder, consisting of at least a compression ring and at least one multi-part oil control ring, the has upper and lower ring bodies and an expansion body, the outer surface of which is in contact with the upper and lower rings, characterized in that the top and lower ring body in the area of their outer peripheral surfaces are provided with a ferrochrome layer applied by spraying, and that the outer surfaces which are in contact with the inner peripheral surfaces of the annular bodies of the expansion body have a layer produced by soft nitriding.

The object on which the invention is based thus essentially becomes thanks to a special coordination of the surface treatment of the multi-part oil control ring achieved.

The piston ring assembly according to the invention is illustrated below with reference to of the drawings and several examples.

1 shows a partial sectional view according to the invention multi-part oil control ring used; Fig. 2 is a partial sectional view of the compression or compression ring used according to the invention, and Fig. 3 is a partial sectional view of a modified embodiment of the invention used multi-part oil control ring.

Fig. 1 shows a multi-part oil control ring made of steel in a Annular groove 4 of a piston 3 is inserted and radially outward against the cylinder wall 1 is being printed or is pending. The oil control ring consists of an upper and a lower one Annular bodies 5A and 5B and a spacer and expanding ring 7 of the partially between the upper and lower ring bodies 5A and 5B placed between them on the one hand in the Keeps distance from each other and they also radially outward against the cylinder wall 1 presses.

According to the invention, on the one hand, the inner circumferential surfaces of the upper and lower ring body 5A, SB with an applied by electroplating or electroplating Chromium layer 2A, 2B and on the other hand the outer peripheral working or

Sliding surfaces of these two ring bodies 5A, 5B with an injection molding process applied ferrochrome layer 6A, 6B provided. The ones with the inner peripheral surfaces the annular body in contact with the outer surfaces of the spacer and expansion ring 7 have been subjected to a soft nitriding treatment in a manner not shown, in order to obtain corresponding nitriding layers. This soft nitriding can occur the way of bath nitriding as well as in other ways, such as sulphonation-nitriding or ionitriding. This will create abrasion resistant, hardened layers in the area the sliding or. Contact surfaces (working surfaces) that come into contact with the cylinder wall standing upper and lower ring body 5A, 5B on the one hand and on the other hand in the area of the contact surfaces of the upper and lower ring bodies 5A, 5B with the spacer and Spreader ring 7 received.

The ferrochrome layers 6A, 6B applied by spraying can be single layers formed solely from ferrochrome, or it can be mixed layers act with ferrochrome as the main component, these mixed layers for example may have two or three further components, for example a self-propelled one Alloy, molybdenum and stainless steel.

According to FIG. 2, a compression ring is in a further annular groove 4 'of the piston 3 8 inserted, which is on its outer peripheral working or sliding surface with a spray-applied ferrochrome layer lo is provided, which is from is of the same type as the ferrochrome layers 6A, 6B.

If two or more compression rings are used, the spray applied ferrochrome layer either in the area of the working or sliding surfaces of each compression ring may be provided, or this ferrochrome layer can only be provided on the first compression ring, while the other compression rings with one through electrical or Electroplating cracked open Chrome layer are provided.

A similar effect in terms of preventing ring wear can also be expected if all or some of these additional compression rings be subjected to a phosphating process instead of a chrome plating process, which contains an iron (III) tetraoxide coating as an equivalent.

The piston ring assembly according to the invention is used in an advantageous manner related to a machine that is operated with a high-flow fuel; the piston ring arrangement according to the invention can of course also be used if unleaded or low-weighted fuel is used. The inventive Piston ring arrangement is suitable for both gasoline and diesel engines suitable in an advantageous manner. The multi-part Clabstreifring shown in Fig. 3 can preferably be used for diesel engines, with this oil control ring the two ring bodies 15A and 15B are in communication with each other, during the according to Fig. 1 related spacer and expanding ring by a coil or coil-shaped Spreading element 17 is replaced.

The main body of the oil control ring shown in Fig. 3 is made generally made of cast iron. In this wiping ring, the inner peripheral surfaces are of the upper and lower ring bodies 15A, 15B in substantially the same manner as in the embodiment according to FIG. 1 with electroplating or electroplating applied chrome layers 12A, 12B provided. The upper and lower ring bodies 15A, 15B are also in the area of their outer peripheral working surfaces with im Spray method applied ferrochrome layers 16A, 16B provided. The outside surface of the spool-shaped expansion element 17 is, on the other hand, a soft nitriding treatment been subjected to nitriding to achieve hardening.

Experiments carried out led to the following results: Machine used: 88.5 mm x 78 mm (cylinder bore x stroke) 4-stroke 4-cylinder gasoline engine Total piston displacement 2189 cm3 11o HP at 520 rpm Fuel used: Highly weighted gasoline (Pb: o, 845 g / l) Piston ring arrangement: see Tables 2 and 3 Cylinder: FC 25 (JIS G 5501) or equivalent material (both in Examples 1 and 2) Table 1 Example 1 (invention) Comparative example 1 (prior art) Cylinder # 1 & 3 Cylinder # 2 & 4 1. Compression ring chrome plating chrome flatting 2. Compression ring chrome plating (tapered) chrome plating (tapered) Multi-part oil removal upper and lower ring body: upper and lower ring body: Streifring outer circumference - ferrochrome sprayed outer circumference - chrome plating travel Inner circumference - chrome plating Inner circumference - chrome plating Spacer and expanding ring: bath nitriding. Spacer and expanding ring: bath nitriding Table 2 Example 2 (invention) Comparative example 2 (prior art Cylinder # 3 & 4 Cylinder # 1 & 2 1. Compression ring ferrochrome spray process chrome plating 2. Compression ring chrome plating (tapered) chrome plating (tapered) Multi-part oil control upper and lower ring bodies: Upper and lower ring bodies: ring outer circumference - ferrochrome injection-molded outer circumference - ferrochrome injection-molding procedure procedure Inner circumference - chrome plating Inner circumference - chrome plating Spacer and expanding ring: Badni spacing and expanding ring: bath nitriding tration In the arrangement shown in Table 1, the outer circumferential surfaces of the upper and lower ring bodies of the air wiping ring had been treated by plasma spraying with a ferrochrome powder (average particle size: (250 mesh) - 0.063 mm) available on the market in order to be used for cylinder No. 1 and 3 (example 1 of the arrangement according to the invention) to obtain the ferrochrome layers 6A, 6B applied by spraying; the outer circumferential surfaces of the upper and lower ring bodies of the oil control rings for the cylinder No. 2 and 4 were hard chrome-plated for comparison purposes with respect to the cylinders 1 and 2 (comparative example 1 according to the prior art), so that the abrasion or the wear of the piston rings through the cylinder walls between the arrangement according to the invention and the prior art could be compared, and the influence of the surface treatment in the area of the upper and lower ring bodies of the oil absorption ring on the wear of the other piston rings could be compared. The results of these investigations are contained in Table 3, the mean degree of wear of the piston rings by the cylinder (depending on the type of surface treatment) results from Table 4, in which the degree of wear according to the following formula as a function of the enlargement of the annular gap ( free gap or slot) between the opposite free ends of each piston ring was calculated: Degree of wear = annular gap enlargement 2 # The spacer and expansion rings or expansion bodies 7 and 17 were subjected to bath nitriding in each arrangement.

Table 3 (example 1 according to the invention) Types of piston rings Cylinder No. Surface treatment Degree of wear (µ / 100 hours) 1. Compression ring 1 chrome plating 13 2 chrome plating 17 3 chrome plating 15 4 chrome plating 19 2. Compression ring 1 chrome plating 15 2 chrome plating 16 3 chrome plating 16 4 chrome plating 18 Multi-part oil drain 1 upper and lower ring body: strip ring outer circumference - ferrochrome Spraying process Inner circumference - chrome plating 27 2 upper and lower ring bodies: Inner and outer circumference - Chrome plating 72 3 upper and lower ring bodies: Outer circumference - ferrochrome Spraying process Inner circumference - chrome plating 25 4 upper and lower ring bodies: Inner and outer circumference - Chrome plating 77 Table 4 Example (No. 1 cylinder) Comparative example (No. 2 cylinder) (Cylinder no.3) (cylinder no.4) State of the art medium level of wear medium level of wear and tear (µ / 100 hrs.) (µ / 100 hrs.) 1. Compression ring 14 18 2nd compression ring 15.5 17 mixed oil drainage 26 74.5 rifle (upper and lower Ring body) According to Tables 3 and 4, satisfactory results were achieved when the ferrochrome layers applied by spraying were in the area of the outer circumferential surface of the upper and lower ring bodies of the air wiping rings, so that the same combination or

Arrangement of the piston rings according to Example 1 in Table 1 for the cylinders No. 1 and 2 of the same machine were used, while No. 3 and 4, the ferrochrome layer applied by spraying is in the area of outer peripheral surface of the first compression ring was located under the same Conditions as above.

The combination or arrangement of the further compression rings took place in the same way as in Example 1 (Example 2) and the experiments (Table 2) were carried out to reduce the wear and tear of the piston rings caused by the Compare cylinders with each other, depending on the different ones Treatment methods for the first compression ring. The results are in the table 5 included, and the average degree of wear by the cylinders (depending on the type of treatment) is shown in Table 6.

The spacer and expansion rings or expansion bodies of the oil control rings had been subjected to bath nitriding in each case.

Table 5 Type of piston ring Cylinder No. Surface treatment Degree of wear (µ / 100 hours) 1. Compression ring 1 chrome plating 17 2 chrome plating 16 3 Ferrochrome spraying process 13 4 Ferrochrome spraying process 9 2. Compression ring 1 chrome plating 17.5 2 chrome plating 11 3 chrome plating 8 4 chrome plating 8 multi-part oil drain 1 upper and lower ring body: 38.5 strip ring outer circumference - ferrochrome Spraying process (upper and lower inner circumference - chrome-plated Ring body) tion 2 "" 29.5 3 "" 24.5 4 "" 25.5 T aballe 6 Example (No. 3 cylinder) Comparative example (No. 1 cylinder) (Cylinder No. 4) (Cylinder No. 2) (State of the art) medium level of wear medium level of wear and tear (µ / 100 hrs.) (µ / 100 hrs.) 1st compression ring 11 16.5 2nd compression ring 8 14 multi-part oil drain 25 34 rifle (upper and lower Ring body) The following was confirmed by the results of the above tests: 1, If the pistons were dismantled after a continuous running time of 100 hours1 and even if tests were carried out at earlier times, no signs of wear or wear were found on the working surfaces of the piston rings and the surface condition of both the piston ring and the cylinder walls was very satisfactory.

2. In those cases where the ferrochrome spray coating on the outer Peripheral surfaces of the upper and lower ring bodies of the oil rings (according to the invention) had been applied, it could be determined that after a continuous running time from 100 hours the degree of wear is reduced to about 1/3 of the degree of wear of the oil control rings coated by the chrome plating process according to Comparative example could be reduced. Although not in the tables above is expressed, the degree of wear on the oil control rings was during the period of time from 50 to 100 hours about 25 μ / 50 hours if the air wipers were chrome plated, while the degree of wear in the case of oil rings made in accordance with the invention were provided with a spray-applied ferrochrome layer, for example 2 5u / 50 Srd.

was, compared to the prior art, a value of about 1/12 means and should be viewed as a significant improvement on normal wear and tear is.

3. According to example 1, not only the degree of wear of the upper and lower ring body of the oil control rings, but also the degree of wear of the first and second compression rings were reduced to 78% and 91%, respectively compared to those degrees of wear When the top and Chrome-plated lower ring body of the oil control rings according to Comparative Example 1 was.

4. If according to Example 2 the ferrochrome layer on both the first Compression ring as well as on the upper and lower ring bodies of the oil control ring was applied by spraying, the degrees of wear and tear of the first and second compression rings and the upper and lower ring bodies of the oil control rings to 67%, 57% and 74%, respectively, compared to the degrees of wear that then occurred if only the upper and lower ring bodies with spray applied Ferrochrome layers were provided.

5. When cylinders Nos. 2 and 4 of the comparative example (the outer peripheral surfaces of the upper and lower ring bodies were chrome-plated) with respect to the surface conditions of the cylinder walls were examined, it was found that very small or tiny holes or pores and the like on the honed surfaces of the cylinder walls were filled with lead oxide, the entire wall being a milky white color.

In the case of No. 1 and No. 3 cylinders (the outer peripheral surfaces the upper and lower ring bodies have been subjected to a ferrochrome spray process are) with a piston ring arrangement according to Example 1, could not have such a surface condition the cylinder walls can be found that had remained clean. Even with the example 2 almost the same results were obtained.

According to the invention not only the abrasion or wear of the the upper and lower ring bodies of the oil control rings are considerably reduced, rather also the abrasion or wear of the first and second compression rings of the same cylinder is considerably reduced as an byproduct. If the Ferrochrome-containing layer formed by spraying onto the compression ring and applied to the upper and lower ring bodies of the oil control rings the wear of each piston ring is further reduced.

Even if a highly charged gasoline is used, it can considerably reduce the wear and tear on each piston ring, reducing oil consumption be kept very low when using the piston ring assembly according to the invention can.

Claims (7)

P a t e n t a n s p r ü c h e 1. Piston ring arrangement for an inside a cylinder movable piston, consisting of at least one compression ring and at least one multi-part oil control ring, the upper and lower ring body and expansion body, the outer surface of which is in contact with the upper and lower Ring bodies is characterized in that the upper and lower ring bodies (5a, or 15a, 15b) in the area of their: inner circumferential surfaces with an electrical or electroplating applied chrome layer (2a, 2b or 12a, 12b) and im Area of their outer circumferential surfaces with a ferrochrome layer applied by spraying (6a, 6b or 16a, 16b) are provided, and that the with the inner peripheral surfaces the annular body (5a, 5b or 15a, 15b) are in contact with outer surfaces of the expansion body (7 resp. 17) have a layer produced by soft nitriding. 2. Piston ring arrangement according to claim 1, characterized in that that at least one compression ring (8) one along the inner wall of the cylinder (1 has a sliding working or sliding surface that is sprayed with a applied ferrochrome layer (10) is provided 3. Piston ring arrangement according to Claim 1, characterized in that it has at least two compression rings, of which the first compression ring in the area of its working or sliding surface is provided with a ferrochrome layer applied by spraying, while each additional compression ring in the area of its working or. Sliding surface with a is provided by electroplating or electroplating applied chrome layer 4th Piston ring arrangement according to Claim 1, characterized in that it is at least has two compression rings, of which the first compression ring is in the area his work or. Sliding surface with a Ferrochran layer applied by spraying is provided, while each further compression ring in the region of its outer peripheral surface is provided with a phosphating layer. 5. Piston ring arrangement according to claim 1, characterized in that it contains at least two compression rings, the first of which is compression ring in the area of his work or. Sliding surface with a spray applied Eerrochrom layer is provided, while some of the other compression rings in the Area of their work resp. Sliding surfaces with an applied by electro- or electroplating Chromium layer are provided, and that each additional compression ring in the area of his outer peripheral surface is provided with a phosphating layer. 6. Piston ring arrangement according to one or more of claims 1 to 5, characterized in that the ferrochrome layer applied by spraying is a single layer consisting solely of ferrochrome. 7. Piston ring arrangement .according to one or more of claims 1 to 5, characterized in that the ferrochrome layer applied by spraying Mixed layers with ferrochrome as the main component and at least one other Component includes.