US1756796A

US1756796A - Exhaust valve

Info

Publication number: US1756796A
Application number: US189228A
Authority: US
Inventors: Noble Warren
Original assignee: Individual
Current assignee: Individual
Priority date: 1927-05-06
Filing date: 1927-05-06
Publication date: 1930-04-29
Anticipated expiration: 1947-04-29

Description

W. NOBLE EXHAUST VALVE April'29, 193,0.

Filed May e, 1927 Patented Apr; 29, 1930 UNITED STATES i 'WARREN NOBLE,`OF DETROIT, MICHIGAN EXHAUST VALVE Application mea may e, 19a?. l serial No. 189.228.

This invention relates to the exhaust valves of internal combustion engines., and has for its object to provide a greater period for the dispel-sing of heat from an exhaust valve through its seat to surrounding metal than is ordinarilyv alforded in exhaust valves as they are usually constructed and operated.

Ordinarily a single exhaust valve is utilized foreach cylinder of an engine and is maintained unseated throughout the entire exhaust period, during which time it is subjected to all of the heating conditions resulting from the discharge of exhaust gases, both when lirst released in a highly compressed lcondition and While being exhausted -by subsequent piston displacement, which results in the heating of the exhaust valve to a high degree. It is when the valve isagain seated that the main dispersing of l this heat takes place through the valve seat and surrounding metal, and it is obvious that the shorter the duration of opening the valve and the longer the subsequent seating thereof the cooler the valve may be maintained.

The' present invention, therefore, has as an object to provide an exhaust valve arrangevment wherein brief opening and extended' seated conditions are obtained, and more particularly to provide for these conditions by the use of two exhaust valves for the same cylinder and the giving to one valve a rapid opening and closing operation during .the early part of the exhaust period, and to the tion, closing at the end of the exhaust period.

Still further the said invention contemplates the utilizing in connection with the cylinder of an engineof dual exhaust valves, each adapted to alternatley open for arelatively short time during the early part of 'the exhaust period and for a relatively extended time closing with the end of the exhaust period, I'so that during one exhaust stroke of an engine onefof the valves operates quickly to relieve compressed exhaust gases and then closes on its seat, While the other -valve opens and remains unseated during the entire exhaust period, thel long and short periods of opening changing alternately from one -valve tothe other with each exhaust stroke of the other valve a relatively extended open dura' engine whereb in continued operation, both valves are subjected to the same heating and cooling conditions.

Still further objects or advantages subsid iary or incidental to the aforesaid objects, or resulting 'from the construction or o eration of the invention as itmay be carrie into effect, will become apparent as the said invention is hereinafter further disclosed.

In carrying the said invention into effect, I may adopt the novel construction and arrangement of parts hereinafter described, by way of example, having reference to the accompanying drawing, Whereinz-` Figure 1 is a fragmentary plan of an engine having a dual exhaust valve arrangement embodying the said invention;

Figure 2 is a transverse section of the Same taken on a plane indicatedV by the line 2"-'- in Figure l; and

Figures 3 and 4 are graphs indicating the action of the said valves.

Similar characters of reference indicate similar parts in the several figures of the drawing.

1 is a cylinder and 2 the cylinder head of an engine, the said head having mounted therein two exhaust valves 3 and 4 common to the cylinder 1. 5 is an inlet valve, the arrangement of which, however, does not enter into the present invention and for that reason will not be further referred to herein. The combined areas of the two exhaust valves is ample for the purposes of proper exhaust, and thev said valves are shown as being operated by rockers 6 and 7 which, in turn, are operated from a camshaft 8.

The form of the cams on this camshaft varies from the common practice, in that, the cams for operation of each of the two valves varies in form to give a different duration of lift to the two valves whereby oneof them opens and closes quickly, whereas 'the other remains open until the end of the exhaust period. To this end the cam of the valve 3 is provided with a lobel 9 having a quick acceleration and short travel, and the cam of the valve 4 is provided with a lobe 10 havinvr an l easier lift and a longer travel exten( ing throughout the full exhaust period. Thus,

it returns to its seat before the completion of thevalves 3 and 4 are given the .relative`action indicated vb the graph,`Figure 3, wherein the vertical imension is indicative of the valve lift and the length indicative of time,` the dotted line 3**.repre'senting the, action of vthe valve 3 andthe solid line 4a the action of thevalve 4. It will be seen from this graph that `duration of the opening ofthe valve 3v under the influence of the cam lobe 9 is short compared with the full exhaust period lso that crank rotation be used and further lobes 11 and l2 provided on the camshaft for operation of the valvesat the required periods. It is also preferred in this case t'o vary the form 'of these lobes so that-the lobe 12 of the valve 4 provides the rapid lift of short duration, and

\ the lobe 11 of the valve 3 a lift of extended and long unseated periods.

' and the valve which has duration, as indicated', so that the action of the valvesunder the inuence of these valves is that shown in the graph of Fi ure 4 from which it will be seen that the va ve 4 opens and closes quickl returning to its seat before the expiration o the exhaust period, and the valve 3 remains open until the end of the exhaust period; this being the reverse of the opration previously described with reference/ for substantially simultaneous' opening of to the lobes 9 and 10.

It will be readilyv seen that this arrangement causes the.valves to alternately change tothe samev alternating conditions of short The result of this is that during each exhaust period one of the 'valves is subjected to the main hot discharge of gases from the cylinder, while `the i other takes care of the neral scavenging, ist opened remains open for only a short time and then reseats before the exhaust lperiod is completed so that it is given an'extended length of time to dissi-` pate its heat through the `walls of the cylinder head while the other valve is still open, this condition changing alternately from one valve to the other asv heretofore stated As a consequence, although ample opportunity is v'afforded for the escape ofthe compressed ',gases, both valvesbeing. o en during the early part of the exhaust period, each valve is actually afforded in actual continued opera- 1 tion a greater durationof seated time than is possible with a single valve which is'required to remain open during the full exhaust period. A

The invention admitsef desirable modifi-,

cations of valve desi due to a more effective coolin thereof as a sult of the action de,- scribe and solves m y of the problems comthe leading monly met with in exhaust valve *practice in a very effective manner as/,Will be readily apparent to those skilled in the-art to'which this invention appertains.

. This invention may be developedwithin the scope of the followinv claims without departing from theessentia -features of the said invcntion, :andit is desired that the specilicationand drawing be read as being merely illustrative and not in alimiting sense, except asnecessitated by the prior art. lVhat I claim is: Y v f l. In combination with an internal coinbustion engine cylinder, two exhaust valves1 and timing means for each of said exhaust both of said valves substantiall simultaneously and to close one of said va ves immediatly after a substantial reduction inpressure a quick lift cam of short angular4 duration operating one of said valves, and a slow lift cam of longer angular duration operating theother of said valves, said cams being timed said valves. v

4. In combinationwith an internal combustion engine cylinder, two exhaust valves, valve-lifting means imposing lifting impulse on one of said valves, and a long valve-lifting impulseon the other ofsaid valves during an exhaust .period of the enginez both impulses commencing substant a alternating in their operation with said first mentioned valve-lifting'means and imposing:

impulses on said valves reversed as to duration during the engine.

5. In combination with' an internal combustion engine cylinder, two exhaust valves, a twolobed cam operating oneof said valves,

a short valvethe succeeding exhaust period of .valves, said timing means, operating to open ly simultaneously, and valve-lifting means v one of the lobes being of short angular dura- Y tion and the other of longer angular dura" -t-ion, and a further two-lobed cam operating the other of the said valves, one of the lobes being of short angular duration and the other of longer an ular duration, the leading..face

of the lobe o long duration ofone cam being"v operative substantially simultaneously with extended dwell periods, said means being.

adapted to retain one lof said valves on its face of the lobe of short dura-- LJ v seat durin substantially one half of one exhaust stro e of the englne and to retain the other of said valves on its seat during substantially half of the next exhaust stroke.

7. In combination in an internal combustion engine two exhaust valves, timing means to begin the opening of said valves substanl tially simultaneously,.said means permitting one of said valves to attain its maximum lift prior to the other of said valves.

8. In combination inan internal combustion engine, two exhaust valves, timing means for beginning the opening of said valves substantially simultaneously, said ,timing means permitting each valve to alternately first reach its maximum lift.

9. The combination as set forth in claim 8, the first of said Valves to reach its maximum lift being adapted to recede from said point prior to attainment of said point by the other valve.

`10. The combination as set. forth in claim 8, 'y

said timing means being adapted to permit the closing of the irst valve to reach its maximum point substantially at the time the other v l valve reaches its maximum point of lift.

In testimony whereof I aiix my signature. WARREN NOBLE.