US1687878A - Internal-combustion engine - Google Patents

Description

Oct. 16, 1928, 1,687,878

A. MOORHOUSE INTERNAL COMBUSTION ENGINE Filed March 28, 1924 Patented Oct. 16, 1928.

UNITED STATES PATENT OFFICE.

ALFRED MOORHOUSE, OF DETROIT, MICHIGAN, ASSIGNOR TO PACKARD MOTOR CAR COMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

INTERNAL-COMBUSTION ENGINE.

Application filed March 28, 1924.

This invention relates to internal combustion engines and particularly to the cylinder and piston parts thereof.

One of the objects of the invention is to provide a cylinder and piston construction in which the lubricating oil in the crankcase and lower part of thecylinder of the engine will be prevented from reachingthe combustion space above the piston while at the same time sufficient oil is supplied to the cylinder walls as the piston operates in the cylinder.

Another object of the invention is to'distribute to the lower part of the cylinder walls of an internal combustion engine some of the oil that reaches the interior wall of the piston.

Other objects of the invention will appear from the following description taken in connection with the drawings which forma part of this specification, and in which:

Fig. 1 is a vertical section through a cylinder of an internal combustion engine with a piston therein made in accordance with this invention, and I Fig. 2 shows more of the piston in section and illustrates a slightly different form of the lower part of the skirt of the piston.

In an internal combustion engine, such as used in an automobile for instance, it is always diiiicult 'to get'just the right amount of oil on the pistons and cylinder walls without getting so much that too much of the oil will get past the piston into the combustion space of the engine where it is burned and wasted.

Most pistons are provided with piston rings for preventing the gases above the piston from getting past the piston into the crankcase and for preventing the passage of too much oil from the crankcase to the combustion space above the piston. Some of these rings are in the nature of scraper rings for scraping the oil off of the cylinder wall on the down stroke of the piston and in some cases the groove in which such ring is arranged is provided with communicating drain passages to the interior of the piston so that the oil so scraped off will be discharged through the piston wall to the. interior thereof. Such means is found effectual in preventing the oil passing the piston but in some cases it is too much so and there is then not enough oil to lubricate the. cylinder and piston surfaces. In the present invention this latter difficulty is overcome by distributing'some of the oil which is in the interior of the piston to Serial No. 702,481.

the cylinder wall on the down stroke of the piston.

In referring to the strokes of the piston as up or down it is understood that refcrence is made to a vertical cylinder engine with the crankcase and crankshaft below the cylinder, and the terms,'therefore, are merely relative.

Referring to the drawing, 10 represents a cylinder of an internal combustion engine, being water jacketed at 11 and provided with a head 12 which is also water jacketed as at 13 and which is provided with the usual spark plug 14.

15 is the piston made in accordance with this invention and 16 is a connecting rod which extends to the crank arm of the crankshaft which is mounted in the crankcase below the cylinder, the crankshaft and crankcase not being shown in the'drawings. The piston is connected to the rod 16 by a piston pin 17.

The upper part of the piston 15 is formed with several piston ring grooves 18, 19 and 20. as shown particularly in Fig. 2, and in these grooves are split piston rings 21, 22 and 23 respectively. Rings 21 and 22 may be of any usual type, and the same is true of ring 23 except that this is preferably a ring having a sharp lower edge as at 24 so that it will perform the function of a scraper ring. This ring is also formed with several slits 25 extending a short distance circumferentially of the ring for the purpose of carrying some of the oil from the cylinder wall to the groove 20 back of the ring. Also, the piston may be beveled off slightly as at 26, just below the groove 20 so that the ring 23 may more effectually perform its scraping function.

The groove 20 communicates with the interior of the piston by one or a series of passages or drain openings 27 so that the oil which is scraped from the cylinder wall into the groove 20 will pass through the piston wall to the interior surface of the piston. Of course ordinarily this oil will run down the interior wall of the piston and drop into the crankcase where it is either splashed bv the crankshaftor is fed to the crankshaft bearings by a circulating pump.

Referring to the piston of Fig. 1, it will be seen that at the lower end of the skirt the piston is exteriorly cut away or rounded off as at 28, so that a tapered space is providedbetween the lower end of the piston and the cylinder wall. The interior of the piston is also beveled somewhat as at 29 so that the oil which runs down the interior wall of the piston, as above described, will reach the ex treme lower end of the skirt where it would normally drop into the crankcase. In the present instance, however, this oil, on the down stroke of the piston, will be drawn into the tapered space between the rounded ofi' portion 28 of'the piston and the cylinder wall and because of the tapering of that space the oil will be distributed to the cylinder wall throughout the down stroke of the pis ton. Of course some of this oil will again be scraped from the cylinder wall bythe ring 23 but not before it has had an opportunity to lubricate the wall throughout its contact with the skirt of the piston between the ring 23 and the lower end thereof. It is evident, therefore, that to some extent the oil scraped off of the cylinder wall by the ring 23 will be constantly circulated from the groove 20 through the openings 27, down the inner wall of the piston to the lower end of the skirt thereof, thence distributed again to the-cylinder wall and again scraped off of the cylinder wall and into the groove 20.

It has been found in practice that this dis tribution of oil by the lower rounded off end of the piston provides ample lubrication for the piston skirt without in any way nullifying the good effects of the scraping action of the 23. n the working stroke of the piston of an rin internal combustion engine, there is, of course,

greater pressure of the piston on one side of the cylinder than on the other, because of the angularity of the connecting rod, and it is on that stroke that the cylinder and piston walls have the greatest need of lubrication. In the present invention, it is contemplated that the rounding otl of the lower end of the piston skirt may be extended upwardly a little farther on that side of the piston where .than to the other.

stroke so that a greater amount of 'oil will be fed to that side of the piston and'cylinder This is well illustrated in Fig. 1 where it will be seen that the cutting away of the piston extends further up on the skirt on the right-hand side than on the other side. On the right-hand side the extent of the rounding off is indicated at 28 and on the I left-hand side it is indicated at 28". The shading of that part of the lower end of the piston skirt that is shown in,elevation illus trates how this cutting away of the piston is graduated from one side to the other.

In 'Fig. 2 the lower end of the interior wall of the piston gradually rounds ofl to meet the rounded off portion 28. This interior rounded off part is indicated at 30. This form of piston ,makes a more direct path for the oil on the inside of the piston to reach'the rounded off portion 28 thereof, but the form shown in Fig. 1- permits of reinforcement of the lower endof the piston and is sometimes preferred. a

While I have herein described in some detail a specific embodimentof my invention, which I deem to be new and advantageous and may specifically claim, I do not desire it to he understood that my invention islimited to the exact details ofthe construction, as it will be apparent that changes may be made therein without departing from the spirit or scope of my invention.

Having thus described my invention, what I claim and desire to secure. by Letters Patent 1s:

In an internal combustion engine, the combination of a cylinder and a piston'there'in, said piston having the end of its skirt exteriorly rounded off more on the side receiv-

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