US 3808955 A
Cylinders of internal-combustion engines, reciprocating-piston or rotary-piston type, made of hypereutectoid aluminum-silicon alloy and formed with a labyrinth of grooves, in checkered or spiral pattern for example, in at least the area of the inner surface along which gastight seal members of the piston slide, said grooves being packed with a dystectic material, such as a ferric alloy, molybdenum, metallic carbide, or ceramic, or a mixture thereof, flush with the rest of the inner surface formed of an aluminum-silicon alloy.
Claims available in
Description (OCR text may contain errors)
United States Patent 1191 Hamada eta].
[1111 3,808,955 [451 May 7, 1974 Assignee:
CYLINDERS OF INTERNAL-COMBUSTION ENGINES Inventors: Yoshitugu Hamada; Yasunori Nakamoto; Seizo Jinno, all of Nagahama, Japan Yanmar Diesel Engine Co., Ltd., Osaka, Japan Filed: Oct. 12, 1972 Appl. No.: 297,092
U.S. c1. 92/169, 123/193 0 1111.01. F0lb 11/02, F02! 1/20 Field of Search 123/193 C; 92/169, 170
References Cited I UNITED STATES PATENTS I 2/1938 Sanders 92/169 8/1942 Sanders i 92/169 5/1967 Jones 92/169 10/1970 lzumi 123/93 C 3,620,137 11/1971 Prasse 92/169 FORElGN PATENTS 0 APPLICATIONS 1,133,041
ll/1956 France 92/169 PrimaryExaminer-Wendell E. Burns Attorney, Agent, or Firm-Ladas, Parry, Von Gehr, Goldsmith & Deschamps 1 ABSTRACT 1 5 Claims, 4 Drawing Figures I PATENTEUMAY 7 1974 SHEET 1 0Fv 2 FIG.
PATENTED MAY 7 I974 SHEU 2" BF 2 F|ej3 'FIG. 4
This invention relates to cylinders of internalcombustion engines.
For the purpose of the invention the term cylinders means the cases each surrounding each piston of an internal-combustion engine and defining a working chamber or chambers therebetween.
With the view to saving the weight of engines and improving their cooling efficiency to. meet increased power output, it is sometimes attempted at using aluminum alloy cylinders without iron sleeves. Usually in such case a hyper-eutectoid aluminum-silicon alloy is used which contains crystallized silicon in the parent metal. The same material has been adopted for the fabrication of side housings of rotary-piston engines having trochoid-shaped cylinders.
I The hyper-eutectoid aluminum-silicon alloy cylinders, which contain hard crystallized sillicon as stated above, are superior in abrasion resistance to the cylinders provided with iron sleeves or chrome-plated on the inner surface, provided that the former is adequately lubricated.
It is known, however, that at the time of cold-weather starting the cylinders of this material tend ,to suffer from objectionable scuffing on the inner surface due to their contact with sliding gastight seal members of the pistons. [Refer to Aluminum engine will power minicar, Product Engineering, Apr. 27, 1970, published by Margan-Grampin Inc., New York, p.54, or Light metal casting and its trends, .IIDOSHA GIJUTSU (Automobile Technology, a Japanese periodical), 26, 4, 1972, p.395.]
The tendency is presumably sttribut'ed to the following facts.
For starting in cold weather the engine must be fed with a rich fuel-air mixture by means of a choke valve. The fuel thus applied in an increased proportion washes away' lubricating oil from the surface along which gastight seal members on each piston slide, thereby leading to very poor lubrication of the surface. (Refer to The Vega 2300 Engine, SAE Paper 710/47, p.4.)
As the gastight seal members slide on'such surface,
ing the possibility of aforementioned'scuffing. As a result, it has now beenfound that the foregoingpurposes can be fulfilled by forming grooves in a certain labyrinth pattern on at least the inner surface portion of the cylinder that is subjected to the sliding contact by gastight seal members of a pistonand depositing a material having a higher melting point than the aluminumsilicon alloy in the grooves so that the surface of the dystectic material filling up the grooves can be flush with the rest of the inner surface, i.e., the exposed surface of the hyper-eutectoid aluminumsilicon alloy. The present invention is predicated upon this. discovery.
The reason for which the scuffing of the inner surface of cylinders in cold-weather starting of an engine can be avoided by the construction above described is yet to be theoretically clarified. However, it appears most likely that, as the gastight seal members of the piston move in sliding contact with the inner. surface of the cylinder, the particles produced by the abrasion of the dystectic material are dispersed and embedded in the aluminum alloy tomake it resistant to scuffing.
. The invention is illustrated, by way of example, by the accompanying drawings in which:
FIG. 1 is a cross-sectional view of a part of a cylinder for a reciprocating-piston engine FIG. 2 is a detail of the portion of the cylinder-encir The labyrinth of dystectic material isformed, forex- I ample,by knurling the inner surface of the cylinder,
they no longer formany lubricant film and come into direct contact with the aluminum alloy surface. .When
this happens, the latter, which is a metal having a relatively low melting point, readily fuses and wears partly with the seal material. This wear due to fusion results in scuffing on the surface of the aluminum alloy along which the piston works.
Such an objectionable phenomenon seldom takes place with the materials as used in the fabrication of iron sleeves that have higher melting points that aluminum alloys.
Naturally the scuffing is precluded by the use of more dystectic materials, e.g., molybdenum, metallic carbides, and ceramics.
In view of this, we made numerous experiments on combinations of hyper-eutectoid aluminum-silicon alloy and various. dystectic materials. The aluminumsilicon alloy is light in weight, easy to cool, and possesses excellent wear resistance under the operating conditions except for the cold-weather start as already pointed out. The experiments were aimed at taking advantage of these features of the alloy and also eliminatthereby forming grooves in a checkered pattern, and spraying a ferrous alloy, molybdenum, metallic carbide, or ceramic, in molten form, over the inner surface, and then removing the resulting deposit from the area of the inner surface'other than the groove surface.
FIG. 2 is a micrographic representation of the portion encircled at A in FIG. 1. The structure consists of crystallized silicon 7, a hyper-eutectoid base 9 of silicon and aluminum, and a dystectic material 11 deposited on the grooves formed on the inner surface 3 of the cylinder.
FIGS. 3 and 4 illustrates another embodiment of the invention as applied to a rotary-piston engine having a trochoid-shaped cylinder, FIG. 3 showing a rotor housing and FIG. 4 a side housing. T
In FIG. 3 the housing l5'is made of a hyper-eutectoid' aluminum-silicon alloy and has a trochoid-shaped inner 3 4 nular surface surrounds a spiralling loop of a dystectic 2. A cylinder as defined in, claim 1 wherein the patmatel'ial 25- tern of the grooves is checkered, striped. dotted. or spi- What is claimed 'is: ral. 1. A cylinder of an internal-combustion engine char- A cylindar as d fi d claim 1 wherein h acterized by the combination of the following features: 5 stectic materia} is a ferrous alloy molybdenum a contacttherewith, and.(3) a dystectic material having (l) made of a hyper'eutectold alummum'smcon tallic carbide, or ceramic, or a mixture thereof.
(2) It formed wlth glooves m a labyrmth H 4. A cylinder as defined in claim I wherein the cylintern in at least the area of the inner surface along wh1ch d t t I b gastight seal members of a piston move in sliding areclpmca mg'pls on m ema us engine.
a higher melting point than the said aluminum-silicon A Cylinder as defined Clalm 1 h the y alloy is deposited in the grooves and exposed flush with def is a trochoid-shaped cylinder in a ry-pi n the rest of the inner surface of the cylinder formed by rna -combust on engine. 5 the hyper-eutectoid aluminum-silicon alloy.