US2393793A - Hydraulic extensible valve tappet - Google Patents

Description

Jan. 29, 1946. o. w. METH HYDRAULIC EXTENSII BLE VALVE TAPPET Y Filed March 7, 1945 I N VEN TOR.

Patented Jan. 29, 1946 UNITED STATES PATENT OFFICE- HYDRAULIC EXTENSIBLE VALVE TAPPET I Orval W. Meth, Sacramento, Calif. Application March 7, 1945, Serial No. 581,433 1 Claim. mil-iza-so) This invention relates more particularly to' an hydraulic extensible valve tappet for internal combustion engines.

Among the object of the invention isto increase the power and efliciency of internal combustion engines by increasing the volume of carbureted fuel intake during the suction cycle.

Another object is to increase the opening speed and lift of tappet valves per unit of cam dis- .placement.

incidental noise and inefficiency of such clearance.

' Another object is to raise the valve head higher from the valve seat so as to present less obstruc- I tion to the incoming fuel mixture and outgoing exhaust gases.

A further "object is to reducethe wear and noise of a metal valve seating on a metal valve The stationary piston 16 hasthe depending skirt l1 sliding freely within the lower chamber I2, with interposed sealing rings, such as IS. The

expansive spring I! interposed between the stationa'ry piston l6 and the bottom l0, normally holds the cylinder 3 depressedso that the bottom l rests upon the dwell interval of the cam 5 on rings '25, 2s. interconnected by'the bypass seat, by retarding and cushioning the descent of the valve assembly; which has a like beneficial effect in the cam assembly. Other objects and advantages will appear as the description progresses.

In the specification and drawing the invention is disclosed in the preferred form. But is to be understood that it is not limited to this form because it may be embodied in modifications within the spirit of the invention as defined in the claim following the description.

In the one sheet of drawing, a valve tappet assembly is shown in vertical section installed in a portion of the engine block, in accordance with this invention. t

In detail the structure diagrammatically shown in the drawing comprises the engine block I, hav

ing a cylindrical guide opening 2, and the lateral vertical guides 3, 4, therein.

The valve tappet assembly is interposed between the cam 5 and the valve stem 6, that is surrounded by the spring 1, expandin between the valve stem guide, on the engine block I, and

the washer 8, bearing against the transverse pin 65 through the valve stem, to normally seat the valve K in the usual manner.

The tappet cylinder! slides freely within the opening 2 and has the closed bottom l0, and the intermediate partition ll, which divides the cylinder 9 into upper and lower chambers l2, l3. This cylinder has the vertical slots ll, l5, registering with the guides 3, 4, in the engine block.

the cam shaft 20. A similar spring as H may be usedin the upper chamber between the dividing wall I l and the inverted hollow plunger 23. The stem 2! on the piston It has the transverse stop bar 22 adjustably mounted thereon and project? ing through the slots l4, l5 and abutting the tops of the guides 3, I.

The upper chamber l3 has the inverted hollow plunger 23, with the skirt 24, sliding freely within the upper chamber with the interposed sealing 21 formed in the wall of the cylinder 9. The plunger 23 has a smaller duct 28 within its wall and opening inside of the head of the plunger 23 and through the skirt 29. The opening of duct 28 at 29 is between thesealing rings 25, 26. The oil line at 3| registers with the upper end of the passage 32 in the wall of the cylinder I. This provides a free circulation of oil from the usual oil pressure system of the engine, from the line 3|,

through the passage 32, the lower chamber l2,

bypass 21,- the upper chamber l3, the 'duct 28 to the outlet oil line 30, during the dwell interval of the cams as shown in the drawing. This oil pressure normally holds the upper plunger 23 elevated into contact with the end of the valve stem 6, and the cylinder head 9 in pressure contact with the cam 5*, without clearance or lost motion between the cam and valve stem. Any air bubbles in the oil pressure system would accumulate in the top of the upper plunger 23 and escape into the outlet 30. Thus assuring acornpact body of oil in the tappetsystem of the invention. A'valve such as 3i in the inlet oil line 3| may be used to regulate the flow of oil to the tappet assembly.

The invention operates substantially as follows: The rise of the cam 5 lifts the bottom of the cylinder 9. against the tension of the spring I9 and stop bar 22. This lifts the whole tappet assembly and displaces the oil from the lower chamber i2, through the bypass 21 into the upper chamber l3, which has the same superficial area and capacity as the lower chamber. The oil filling the. chamber I3 lifts the plunger 23, and the The upper and lower chambers are I and leaves practically no residual burned gases The volumetric displacement from the lower chamber [2, displaces the plunger 23 upward higher and at greater speed than the rise and speed of the larger cylinder 9. In this manner, increasing the mere height and mechanical lift of the cam 5, if directly acting against the valve stem 6 in the usual practice.

In the present instance the valve rising faster increases the length of the time interval in the fuel intake cycle, increasing the fuel volume taken into the engine cylinder during the suction cycle. The rise of cylinder 9 upon the skirt I I of the stationary piston l6 shuts off the'lower end of oil passage 32 at 33, and the rise of the skirt 24 on the upper plunger closes the escape of oil through the line 30, leaving the tappet assembly packed with oil to capacity.

As the cam begins its descent the lowering of the cylinder 9 under the tension of the spring l9 and the tension of the spring 1, provides space for-the oil being displaced from the upper chamber through the bypass 21 by the expansion of the valve spring I, until the duct 28 again reg- This bypass open ing 21 being relatively small, acts as a dash isters with the outlet line 30.

pot restricting the flow from the upper chamber l3 and retarding the closing of the valve of the stem 6.- This retards the closing of this valve haust cycles; improved thermal efllciency due to an increased volume of cold fuel gases and .a more complete exhaust of hot burned gases; less wear and tear on valve assemblies and valve seats, due to retarded closing and the absence of noisy tappet clearances. Motor balance is improved and greater speeds are possible because of the improved general performance of the reciprocating parts under better balanced stresses.

In overhead valve in the head systems having rocker arms working directly on the valve stems,

X at the end of the intake cycle, thereby lengthening the suction cycle and increasing the volume of fuel gas taken into the engine cylinder.

When the hydraulic tappet assembly, according to this invention, is interposed between the cam 5 and the stem 6 of the exhaust valve asthe exhaust valve, which increases the exhaust interval. This improves the scavenging efllciency,

in the engine cylinder to dilute the incoming fuel of the succeeding suction cycle.

Some of the advantages of this invention are, increased horse power output, due to more efficient ,valve operation in the suction and exthe present invention can be interposed between the cam actuated push rods and the rocker arms; or otherwise applied to the various types of tappet valves.

Having thus described this invention and its mode of operation, what is claimed and desired to secure by Letters Patent is: a

In an internal combustion engine having. a block with an oil line with a valve therein, a cylindrical guide, and a cam and valve stem operative therein; an extensible tappet assembly comprising a cylinder having side slots through its wall and slidable in said guide with its bottom resting on said cam and an inlet oil passage in its wall registering with said Oil line and terminating near said bottom; and an outlet passage through said wall registering with, the outlet opening of said oil line, whereby the passage of oil through .said line isstopped when said cylinder is lifted by said cam; a partition dividing said cylinder into lower and upper-chambers,

Images