US1357413A - Gas-engine cam - Google Patents

Description

E. V. MYERS.

GAS ENGINE CAM.

APPLICATION FILED MAR. a, 1920.

Patented Nov. 2, 1920.

INVENTOR M KM By A llorneys,

warren stares EUGENE V. MYERS, OF EAST ORANGE, NEW JERSEY.

GAS-ENGINE CAM.

T 0 all to 710m it may concern Be it known that I, EUGENE V. MYERS, a citizen of the United States of America, residing in East Orange, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Gas-Engine Cams, of which the following is a specification.

This invention relates to cams for explosive engines, and particularly the fourcycle type.

In this type of engine the cam being mounted on a half speed shaft has at the maximum a quarter of its circumference devoted to the rise, dwell and fall of the cam. I-Ieretofore such cams have been made as small in circumference as would give the necessary upward movement of the valve the exhaust stroke. As a result the capacity of the intake and exhaust valves has been much less than that which is necessary to secure the full power of the engine especially when the engine is working at its most efiicient speed, the intake wire drawing and the exhaust building up a pressure within the cylinder, with the result of imperfect scavenging. To overcome this difficulty, it has been customary in the modern practice to build the engine with two exhaust valves and two intake valves, thereby doubling the capacity of the inlet port and the outlet ort. p I have found that if the cam be largely increased in size, say to two, three or four times its customary size, very much improved results can be obtained. That is to say, the dwell of the cam can be increased to fifty or more degrees out of a possible ninety, thereby moving the valve quickly to wide-open position, and holding it in wideopen position for a relatively long time during the stroke of the piston and promptly closing it. The capacity of the valve is hence much increased.

Specification of Letters Patent.

Application filed March 3, 1920.

Patented Nov. 2, 1920.

Serial No. 362,929.

tice that the rise B and drop D shall be tangential to the circle of the cam. These are continued in a tangential direction until the proper lift of the cam is reached. They are then connected with a curved portion which constitutes the dwell C. In the drawmg I have illustrated the dwell C as rather abnormally long from the standpoint of actual practice, it being shorter in many cases than that illustrated. The angle E in this construction is about 18, and it follows that the l1fter rod is operated to its full height for about the same period during the revolution of the cam shaft.

Referring now to the cam provided by the invention, which is designated by the letter A, it will be observed that the rise B and drop D are also struck tangentially from theperiphery of the cam. In point of linear extent it will be found that the rise and drop are longer than the rise and drop on the cam A. In point of ascent from the periphery, it is hence evident that the valve rod rises a more gradual incline, or has a more gradual lift than with the cam A. The dwell C, which is of the same height as the dwell C, is, however, greatly increased in length, with the result that the valve is held wide open a much longer period than with the cam A. In the device illustrated the angle E is approximately or nearly three times as great as with the cam A. Hence the valve is kept open aomuch longer period during the 90 allotted for its movement.

It is recognized that the peripheral speed of the cam A is much greater than that of the cam A, so that it travels past the valve rod at a much greater speed per linear measurement than. does the cam A. With the same type of rise and drop, however, the incline up which the valve rod travels is no greater than that of'the cam A; indeed, it is about 70 per cent. longer. The greater speed of peripheral travel of the cam A, therefore, does not introduce any i, "Maw-k materially "greater side thrust on the valve rod.

This result cannot be obtained with a small cam having the necessary lif 7 It is obvious that the rise or drop, or either, can have any suitable shape. If it be desired to ease the drop, so as to more gradually seat'the valve, a suitable shape can be adopted for this purpose, and it desired, a portion of the dwell can be sacrificed for this purpose. So also on the rise the valve may be initiallylifted from its seat,

or its inertia overcome, at the start by a more gradual rise. The tangential rise and drop, however, have proven to satis factory and are illustrated on this account. While I have shown and described one form of the invention, it will he understood that I have not illustrated the essential form of engine which may be of any ordinary type or the lifter rod or valve rod, since these may be of any usual or customary construction.

WVhat I claim is 1 1. A valve cam for four-cycle internal combustion engines, of large dlameter, having" a rise, a dwell and a drop arranged .Within 90 of the cam shaft, and having a dwell of approximately 50 of such shaft 2. A valve cam for four-cycle internal combustion engines, of large diameter, having a rise, a dwell, and a drop arranged within 90 of the cam shaft, and having a dwell of approximately 50 of such shaft,

the rise being substantially tangential to signed my name. 7

Y EUGLNE V. MYERS.

Images