US1632988A - Internal-combustion engine and method of operating the same - Google Patents

Description

June 21, 1927. 1,632,988

E. T. ADAMS INTERNAL COMBUSTION ENGINE AND METHOD OF OPERATING THE SAME Original Filed Aug. '7. 1920 III/III, I'll," ""o, i

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Patented June 21, 1927.

UNITED STATES 1,632,988 PATENT OFFICE.

EDWARD '1. ADAMS, OI BELOIT, WISCONSIN, .ASS IGNOR T0 FAIRBANKS, MORSE & ('10.,

OF CHICAGO, ILLINOIS. A CORPORATION OF ILLINOIS.

INTERNAL-COMBUSTION ENGINE AND METHOD OF OPERATING THE SAME- Application filed August 7, 1920, Serial No. 401,859. Renewed May 10, 1923.

My invention relates to internalcombus tion engines, and the method of operating same. The object is to provide improved methods and means for clearing the cylinder of burnt gases.

In two-cycle engines, with exhaust and air inlet ports controlled by the action of the main piston, the time during which scavenging air can be admitted is extremely limited and thoroughly clearing the cylinder of burnt gases is only accomplished by careful attention to detail in the design and operation of the entire scavenging system.

In the ordinary two-cycle engine, the scavenging air tends to mix with rather than to displace the burned gases within the cylinder. This is due to the necessity of opening the scavenging ports too early in the stroke, with the result that the pressure in the cylinder is often greater, at that instant, than is thepressure in the scavenging air receiver, and the first effect is a flow of burned gas into the receiver mixing with the air, the second eifect is that as the cylinder and receiver pressures equalize, the scavenging air issues at first with very low velocity and again tends to mix with the burned gases rather than displace them.

The object of my invention is to overcome these defects, first by causing the air scav-' enging ports to begin to open late in the stroke, second, to do this and at the same time to hold them or a part of them open as long as is necessary, third to permit a design in which the air may be given a strong directional flow along the side of the cylinder and toward the cylinder head. Fourth, to allow a design in which scavenging air is admitted in a sustained directed flow rather than in 'a sudden violent blast. Fifth, to permit a construction in which one may readily make use of scavenging air from diiferent sources, as (a) air to one set of ports from crank case for example, and air from another source such as an auxiliary compression cylinder,

in which case the latter would preferably be timed or set to pass its center and reach the limit of its air delivery at ornear the time when the scavenging ports so fed are closed.

It is preferable to cause the scavenging air ports to open. late in the stroke, at a time when the pressure within the cylinder will be less than the air receiver pressure. This will cause thescavenging air to flowinto the cylinder with considerable velocity andv near the cylinder head which will increase" in volume and force the burned products back and out through the exhaust ports.

Referring to the drawings, which illustrate merely by way of example, suitable means for the embodiment of my invent1on:

Fig. 1 is a central vertical section.

Fig. 2 is a horizontal section on line 2-2 of Fig. 1.

Similar numerals refer to similar parts throughout the several views.

The cylinder 5 is provided with the exhaust ports 6 and the short inlet ports 7 controlled by the main piston 8 and the cooperating long inlet ports 9 controlled by the valve 10, as well as by the main piston.

These ports 7 and 9 are in part co-extensive,

that is, with their margins remote from the cylinder head, plane.

When themain piston alone controls the air inlet ports, late opening of these ports necessarily involves their early closing, and complete scavenging does not take place without either undue length of exhaust port or high pressure of scavenging air. I overcome this by dividing the scavenging air ports into two parts or cooperating sets. First, a series of short ports 7 which open late and close early. Second, a series of very long ports 9 which are opened by a valve 10 correspondingly late in the scavenging cycle and are closed still later preferably by the main piston 8. It is not necessary that these two classes of air inlet ports shall re ceive their air supply from separate sources although they may do so; the-one set receiving air, for example, from compression in the crank case, the other set receiving air from a compression cylinder or the scavengall in substantially the same I ing air compressed in any manner, Ina be contained in one receiver from which oth series of ports are fed or ma be forced into separate containers one or each set of valves. This is merely a. detail governed in part by the area and length of the respective air ports. "The essential feature is that by suitably arranged and controlled ports, am. able to open the air inlet ports latein the stroke, when the exhaust pressure is low and there will be, from the start, velocity to give direction to the flow of incoming air, and at the same time some of the ports shall remain open long enough to insure thorough scavenging of the cylinder.

The division of the-air ports into two classes, one piston controlled the other valve and piston controlled, has very great mechanical advantage. In an engine of this class the air ports should extend around fully 180 degrees of cylinder circumference, and any scheme for valve control of the entire volume of a scavenging air is. faulty which permits a large volume of exhaust gas to flow back and fill a large volume of space between the port in the cylinder and the air control valve. Such fi'ow occurs after the port is opened by the piston and before the air passage is opened bythe valve, and we have the undesirable mixing of air and burned gas. In such case the volume of air left in this intermediate space at the end of the scavenging period on one stroke is mixed with the burned gas at the end of the next workinw stroke and before scavenging begins. This volume .of air is almost entirely wasted. It mixes with the burned gas and there is no possibility of utilizing its velocity of flow to displace such products.

In my construction I utilize the short piston controlled ports to their fullest extent and I also use the cooperating valve controlled ports, which structurally are arranged to have but little volume between the ort and the valve, and for which the va ves themselves are small and easily controlled.

A further benefit arising from this system is that it lends itself readily to a preferred construction in which the inflowing air is given a strong directional flow along the side of the cylinder up or back toward the cylinder head tending to accumulate air near the cylinder head and to displace the burned gases from that point toward the exhaust port; and in my preferred construction, I find that this double system of air inlet ports allows me to carry'this dircctional idea to a point where the valve controlled ports are mere grooves in the side of the cylinder and yet the volume between valve and port is small and the lost air is reduced to a minimum. 1

It is obvious that with the ordinary piston controlled scavenging air ports, no matter when the port is opened, scavenging air is not admitted to the cylinder until the pressure within the cylinder is less than the air pressure in the receiver or transfer ports, and necessarily savenging ends when the main piston closes the air ports. With the proposed constructionscavenging air enters as before as soon as the pressure in the cylinder drops to a predetermined amount and continues if desired even after the exhaust port is closed and, although the valve opens late, the time during which air actually enters the cylinder is actually prolonged, and also by controlling the area of the ports and the time of valve opening it is possible to attain a sustained flow of air throughout the scavenging period all directed if desired along the same course and toward the same part of the working cylinder.

It will be noted that in my construction, the top of piston 8 and air passages 9 are so formed that the air flows through a venturi shaped passa e which converts pressure into velocity an is very favorable to a strong directional flow with the least possible loss of energy.

This construction further permits a strong directional flow of the incoming air without the use of grooved passages in the end of the piston or so-called deflectors of any kind.

What I claim is 1. The method, in operating internal combustion engines, which consists in introducing initially in a plurality of streams, a maximum fiow of scavenging air before the end of the power stroke, but substantially after the beginning of exhaust, when the pressure in the cylinder hasbeen materially reduced, in order to, securevelocity and direction of said ginflowing streams of air, interrupting some-of said streams earlier, and continuing unbroken other of said initial streams of flow later during the continuance of the exhaust.

2. The method, in o crating internal oombustion en es, whic consists in introduc-.

ing initial y in a plurality of streams, but in a common lane, a maximum flow of scavenging air fore the end of the "stroke, but substantially after the the cylinder has been materially reduced, in order 'to secure velocity and direction of said inflowing streams of air, interrupting some of said streams earlier, and continuing unbroken other of said initial streams ofv flow later'during the continuance of the exhaust.

v 3. The method, in 0 rating internal com maximum ow of scavenging air before the mwer .ning of exhaust, when the pressure in mamas end of the power stroke, but substantially after the beginning of exhaust, when the pressure in the cylinder has been materiall reduced, in order to secure velocity and direction of said inflowing streams of air, interrupting some of said streams earlier, and continuing unbroken other of said initial streams of flow later during the continuance of the exhaust, and converting pressure into velocity in connection wit said continuing flow.

4. An internal combustion engine cylinder provided with a plurality of admission ports having their margins remote from the cylinder head, all in substantially the same plane, some of said ports extending toward the cylinder head beyond other of said ports, and means cooperating therewith, whereby all of said inlet ports open simultaneously, after the beginning of the exhaust and before the end of the power stroke, and whereby some of said ports close substantially before the end of the exhaust and some approximately with the ending of the exhaust.

5. An internal combustion engine cylinder provided with a plurality of admission ports extending around the cylinder more than one hundred and eighty degrees, having their margins remote from the cylinder head, all in substantially the same plane, some of said ports extending toward the cylinder head beyond other of said ports, and means co-operating therewith, whereby all of said inlet ports open simultaneously, after the beginning of the exhaust and before the end of the power stroke, and whereby some of said ports close substantially before the end of the exhaust and some approxunately with the ending of the exhaust.

6. An internal combustion engine cylinder provided with a plurality of admission ports having their margins remote from the c linder head, all in substantially the same piano, some of said ports extending toward the cyllnder head eyond other of said ports, and means co-operating therewith, including a valve controlling some of said ports and positioned closely adjacent thereto to prevent dead spaces, whereby all of said inlet ports open simultaneously, after the beginning of the exhaust and before the end of the power stroke, and whereby some of sald ports close substantially before the end of the exhaust, and some approximately with the ending of the exhaust.

7 An internal combustion engine cylinder provided with a plurality of admission ports having their margins remote from the EDWARD T. ADAMS.

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