US 1156447 A
Description (OCR text may contain errors)
J. M. UNDERWOOD.
EXHAUST FOR INTERNAL COMBUSTION ENGINES.
APPLICATION FILED 050. II. I9I3.
1,156,447. Patented Oct. 12, 1915.
t I gvwa'n foc 1 names WW eMlvmwWmmmfwawd I I I I III I Mo we ("I HOT/nua- JOHN M. UNDERWOOD,
or rants, ARKANSAS.
EXHAUST FOR INTERNAL-COMBUSTIONENGINES.
Specification of Letters Patent.
Application filed December 11, 1913. Serial No. 805,967.
To all whom it may concern.
Be it known that I, JOHN M. UNuEnwooo, a citizen of the United States, residing at Paris, in the county of Logan and State of.
I ity of a return of the exhaust products, and
at the same time relieving the vacuum which frequently obtains in the exhaust pipe and pocket of the engine immediately following the closing of the exhaust valve.
To these and other ends, the nature of which will be readily understood as the invention is hereinafter disclosed, said invention consists in the improved construction and combination of parts hereinafter fully described, illustrated in the accompanying drawings, and more particularly pointed out in the appended claim.
In the accompanying drawings, in which similar characters indicate similar parts. Figure 1 is a vertical sectional view taken through the attachment and the pipes leading to and from the attachment. Figs. 2 and 3 are sectional views taken on the lines 2-2 and 33 respectively of Fig. 1.
When the exhaust valve of an internal combustion engine closes at the end of the exhaust stroke, the pressure tending to drive the exhaust gases out of the exhaust pipe is of course suddenly cut off. During the movement immediately following the closing of the exhaust valve, however, the gases continue to rush through the exhaust pipe because of their inertia. Thus a partial vacuum is created at the inner end of the exhaust pipe (or exhaust pocket as it is sometimes called). In case the exhaust valve does not seat properly a small amount of the exhaust gases may be drawn back into the cylinder during the first part of the intake stroke.
The structure devised by me for overcoming this difficulty is shown in the accompanying drawings, consisting of a three-way casing 10 having one of its openings 11 adapted to be threaded to the exhaust outlet 12 of the cylinder, the other two openings being substantially in vertical axial alinement, and an enlarged portion 13 being threaded to thecasing, to form a continuation of the upper opening 14, while the lower portion of the casing is enlarged, as at 15, w th the lower opening 16 threaded to recelve a valve seat 17, to which, ifdesired, a
pipe 18 may be secured. The enlargem'ent 13 has 1ts outer end threaded to receive the eX-' haust pipe 19.
In each of the enlarged portions 13 and 15 of the attachment, I mount valves 20 and 21, these being supported in suitable spiders 22-. These valves are adapted to operate by gravity, the valve 20 being adapted to open when pressure is placed within the casing,
while the valve 21 is adapted to be opened under suction action within the casing. The valves are of a weight which will provide for maximum efliciency.
Regarding the operation of the attachment it will now be seen that during the exhaust stroke of the engine piston the burnt gases will be forced out under pressure and will escape through the valve 20 to the atmosphere through the pipe 19. At this time the internal pressure in the casing 10 together with the action of gravity holds the air valve 21 closed. When the exhaust valve of the cylinder closes, however, the pressure tending to unseat the valve 20 and drive out the exhaust gases will be cut 0E. The inertia of the gases is sufficient to cause their continued passage throughthe valve 20 for a moment only. This continued passage of the gases after the closing of the exhaust valve of the cylinder results in the production of a partial vacuum in the pipe 12.
Patented Oct. 12 i915.
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This vacuum is relieved by the preseht device sincethe valve 21 lifts under atmospheric pressure to admit sufiicient fresh cool air in the casing 10. It is now to be explained that the opening of the air valve 21 is accompanied by a closing of the exhaust valve. 20. Thus the exhaust gases present in the pipe 19 when the exhaust valve of the cylinder closes are prevented from finding their way back to thepipe 12.
The attachment may be formed in various ways for convenience in assembling, the preference being that the openings 14 and 15 be positioned in vertical axial alinement, although this may be varied to some extent without departing from the invention, the principal essential of which is that the outlet be located above the inlet for the air in order that the valves may operate by gravity and be of a type which will function with accuracy and freedom of movement.
Having thus described my invention, what T claim as new is:
The combination with an exhaust pipe of an' internal combustion engine of a casing connected to the pipe, an outwardly opening valve for the casing controlling the issuance of exhaust gases therefrom, and an inwardly opening valve controlling the admission of air to the casing, said first mentioned valve being adapted to remain open and said second mentioned valve being adapted to re main closed during the exhaust stroke of the engine and While the exhaust valve of the engine is open, said first mentioned valve.
In testimony whereof I hereunto aflix my signature in presence of two Witnesses.
JOHN M. UNDERVVOOD. \Vitnesses:
\V. G. RILEY, J. C. RILEY.