US1784640A - Poppet valve - Google Patents

Description

Patented Dec. 9, 1930 UNITED STATES WARREN NOBLE, 0F DETROIT, 'MICHIGA'N POPIPET VALVE No Drawing.

This invention relates to the poppet valves of internal combustion engines in connection with which considerable thought and experiment has been exercised in the past by valve and engine designers with a view to perfecting a valve which would satisfactorily withstand the temperatures to which the valves and especially the exhaust valves of internal combustion engines are exposed in use.

Among the means employed or suggested have been exhaust valves with special means for cooling the stems such as the flow of heat conducting agent therethrough with a view to disperse heat from the head of the valve through the stem thereof and on the other hand attempt to meet the problem with more or less success have involved the use of special heat resisting alloys from the heads of the valves calculated to withstand high temperatures in view of the difficulty of getting rid of this heat quickly.

The present invention differs materially from this latter attempted solution of the problem in that it provides a valve head of a metallic composition or alloy which is characterized by its heat conducting properties as distinguished from purely heat resisting properties whereby it lends itself to rapid dissipation of its heat radially from the valve head to the seat of the valve and also through the stem thereof if heat dissipation in this direction he also desirable.

More particularly the said invention contemplates of the use of silver, a metal having a very high co-efficient of heat, said silver being alloyed with a suitable metal or metals to give it the required strength and wearing properties required in the head of a poppet valve adapted to use in an internal combustion engine. In carrying. the invention to effect I prefer to use a composition including magnesium 10 per cent and silver 90 per cent which may have a tensile strength in excess of 63,000 pounds and a Brinell hardness ranging above 105. I may use as an alloy for a poppet valve head a composition including for example aluminum 15 per cent and silver 85 per cent, such a composition having a tensile strength ranging above 40,000 pounds and Brinell hardness ranging Application filed. September 15, 1.927;, SeriaI NoJ 219,814;

above 140. Both of these comp ositions'are homogeneous and lend themselves well to finishing by grinding and lappingiof seating surfaces free from pits and open structure.

' Silver has very high co-eflicient'of heat conductance, and alloying with aluminum or magnesium within reasonable limits does not reduce the conductivity to such an extent that its advantage is lost, so that the high heat conductivity ofvalve headsmade from such composition is' a typical characteristic.

' Poppet valves depend mainly .for their heat dissipation on the transfer of heat therefrom' to the valve seats and incidentally through the valve seats to metal or cylinder heads but it is obvious that this dissipation is facilitated by the use ofa metal or alloy in the headiwhich has this special characteristic and that therefore as a resultof the heat dissipation so promoted, the general temperature of the valve head is lower than would otherwise be the'case and. that heat resisting nature of the headi's asra consequence a matter of less importance.

Although the use of such a composition is described simply in connection with the head of a valve it may be also partly or entirely extended to the stem of the valve if so desired where conditions of the enginedesigned are such that some of the heat may be dissipated through the stem.

A valve in which a silver alloy as suggested is used for the purposes of obtaining high heat conductivity in the head thereof may be very advantageously used with the heat conductive valve seat described in my copending application Serial No. 219,813, filed Sept. 15, 1927 an arrangement which still further increases the facility with which heat may pass from the valve to the metal of the cylinder head of the engine.

What I calim is 1-. In a poppet valve for internal combustion engines, a head composed of a binary alloy of silver and a metallic hardening agent wherein the silver predominates to an extent wherein its inherent co-efl'icient of heat conductivity is characteristic of the alloy, and wherein the hardening agent imparts wear resisting properties to the head.

2. In a poppet valve for internal combus tion engines, a head composed of a magnesium silver alloy in which the silver predominates to an extent wherein its inherent co-eflicient of heat conductivity is characteristic of the alloy, and wherein the magnesium supplies to the alloy great wear resisting 1 properties.

3. In a poppet valve for internal combustion engines, a head composed of a magnesium silver alloy wherein the approximate proportions of the elements are 10 per cent magnesium and 90 per cent silver.

4. A poppet valve for internal combustion engines, composed of a binary alloy of silver and a metallic hardening agent wherein the silver predominates to an extent wherein its inherent co-eflicient of heat conductivity is characteristic of the alloy, and wherein said hardening agent imparts wear resisting qualities to the head and stem of said valve.

5. A poppetvalve for internal combustion engines, composed; of a magnesium silver alloy in which the silver predominates to an extent wherein its inherent co-efiicient of heat conductivity is characteristic of the alloy, and wherein the magnesium imparts wear resisting properties thereto.

6. A poppet valve for internal combustion engines, composed of a magnesium silver alloy wherein the approximate proportions of the elements are 10 per cent magnesium and 90 per cent silver, and with a suflicient quantity of magnesium included therein to impart wear resisting properties to said valves.

In testimony whereof I aflix my signature.

WARREN NOBLE.