US2014659A - Internal combustion engine - Google Patents

Description

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Filed July 2o, Y1952 NUUEHDUSE Patented Sept. 17, 1935 UNITED STATES Y 2,014,659 INTERNAL CoMBUsTIoN ENGINE Alfred Moorhousc, Detroit, Mich., assignor to Packard Motor Car Company, Detroit, Mich., a corporation of Michigan v Application July 20, 193,2, Serial No. 623,506v

13 Claims.

This invention relates to internal combustion engines and particularly to the valve operating mechanism thereof.

f The invention is in some respects an improvement upon the valve mechanism shown in British Patent bld-289,468, and U. S. patent applicationl to Edwin Storey, Ser. No. 574,795, filed November 13, 1931. In said British patent and in said application there is described a valve mechanism for internal combustion engines in which the rocker arms are provided with a takeup mechanism to compensate for expansion and contraction due tol temperature variations. In

the British patent the take-up device is mounted 15 below the pivot of the rocker arm and the piston oi the device presses upwardly, thus leaving the cylinder of the device open at its upper` end so that any air in the device may escape upwardly Yaround the piston. VThere is a spring pressed valve inthe movable, piston.

In the Storey application the take-up device is mounted above the pivot and the piston presses downwardly, the upper end of the cylinder being closed except for a spring operated valve.

125 Whilethe British patent indicates that its spring pressedv valve will be opened by the vacuum created by the upward movement of the piston, it is found in practice and it is recognized by Storey that a contributing factor to the opening of this valve is the inertia of the parts and that the sudden movement of the piston causes the Vopening of the valve to permit escape of air oriniiow of oil.

This matter ofV escape of air from'the working 535 parts of theV cylinder is of utmost importance because if air is trapped below the pistonthe valve mechanism will not operate quietly since the air will be compressed instead of forming a solid wall and the eccentric mounting will then cause "40 a clearance between the rocker arm and the engine valve. Hence the necessity for providing means for completely eliminating the air from side of the center line oi the engine and it is unthe high pressure space of the device.

It is one of the objects of the present invention "145 to.improve upon the devices of the British patent and the Storey application, particularly in this matter of eliminating the air from the high pressure chamber of the device.

It is an object of the invention that the device T shallrnot only have its valve at the upper part of wardly from the upper part of the high pressure chamber so that the air in the device will be (Cl. 12S-90) forced out at that point when the device is under compression.

Another object of the invention is to provide for circulation of the oil inthe device itself, downwardly through the spring pressed valve into 5 the high pressure chamber, and upwardly from the upper end of the compression chamber into a chamber at the upper part of the device which is open to the atmosphere. Thus the air will l escape from the oil and after all of the air has 10 been -eliminated from it this same airless oil will continue to be use d in the device and thus improve its operation.

Other objects of the invention will appear from the following description taken in connection`15 with the drawing, which forms a part of this specication, and in which the figure is a vertical transvers-e section through the central portion of a V-type internal combustion engine embodying the invention. 20

Referring to the drawing I represents generally a cylinder block casting which may or may not be a single casting, as shown in the drawing. Mounted in bearings II in the casting is a cam shaft 52 and above the cam shaft is an openingl25 I3 in which is mounted a casting or support I4 which supports the valve operating mechanism. One of the rocker arms for the valve mechanism is indicated at I5, and this rocker arm is provided with a roller I6 which contacts with a cam 30 on the cam shaft I2, and the other end of the arm has a contact point Il operating on the end of the engine valve I8. The latter valve is closed by a spring I8. `The rocker arm is mounted upon an eccentric sleeve I9 on a pin 29, which.` 35

,sleeveV hask a lever arm 2l extending radially therefrom for the purpose of rotating it slightly on the pin 2l) and thereby adjusting the clearance between the roller I S and the cam shaft and the point I'I of the rocker arm and the valve 40 I 8. There is a similar pin 20 on the opposite derstood that similar rocker arms are mounted thereon, there usually being one rocker arm and take-up mechanism rfor each engine valve. 45

Mounted above the lever arm 2| is the take-up device of this invention. It is indicated generally at A and it comprises an inverted cylinder 25 which may be formed directly inthe casting o1' support I4 as shown in the drawing. This is a 50 stationary cylinder and `it is integrally closed vat its upper end except for an opening 26 into which is tted the stub end 2l of a piston 28. This is a stationary piston and in eiect forms a part of the cylinder 25. It is somewhat smaller than the 55 interior diameter of the cylinder 25 and it abuts against the closed upper end of that cylinder.

The piston 28 is in two parts for convenience in manufacture and assembly, the parts being indicated at 29 and 38, but these parts remain together after the device is assembled and there is no relative movement between them. The interior of the piston 28 is open to the interior of the cylinder 25 at its upper end by reason of passages 3|, and the piston 28 has its lower end closed except for a passage or opening 32 which is closed by a spring pressed valve 33, the Valve opening downwardly and being held to its seat by a light spring 34. The valve stem 35 of the valve 33 extends upwardly through an opening 36 in the upper end of the stub end of the piston, the iit being loose so that the valve may readily find its seat. The lower end of the spring 34 rests against the end of the piston 28 and the upper end operates against a flanged sleeve 31 held on the valve stem 35 by a split ring 38 in a groove in the Valve stem.

A movable hollow cylinder 40, which may be called the working cylinder, extends up into the stationary cylinder 25 and surrounds the lower part 30 of the piston 28, the t between the outer wall of the piston part 30 and the inner wall of the cylinder 4D being such that leakage may occur under high pressure and thus form a dashpot as liquid is expelled from the cylinder under pressure. The fit between the outer surface of the movable cylinder 40 and the inner surface of the stationary cylinder 25 is fairly close so that there may be very little leakage and the stationary cylinder may form an adequate guide for the movable cylinder.

The lower end of the cylinder 40 is formed with an extension or nose 4| which rests against the lever arm 2| of the sleeve I9, and a spring 42 between the lower end of the piston 28 and the movable sleeve tends to constantly press the latter against the lever arm 2|, for the purpose above described.

The space between the lower end of the piston 28 and the head of the cylinder 40 is a high pressure chamber indicated at 43, the high pressure being caused by the operation of the valve mechanism in which the cam tends to rock the rocker arm |5 against the valve spring I8', thus constantly pushing upwardly on the lever arm 2|. As the rocker arm |5 drops off of the cam and the Valve |8 is closed, the spring 42 returns the cylinder 40 to its original position and takes up the clearance at either end of the rocker arm. During this latter movement, if the liquid within the high pressure chamber 43 has been pressed out to any extent between the cylinder 40 and the piston 28, it will be drawn back in again by reason of the partial vacuum created therein, the valve 33 opening to permit the liquid to again enter the high pressure chamber.

But it is found that the partial vacuum created is not always suiiicient to open the valve 33 and consequently a small cylinder 44 is formed Within the cylinder 4D, and an extension 45 is provided on the lower end of the Valve 33, and a piston 46 forms the lower end of said extension 45. This piston 46 is just slightly smaller than the inner diameter of the cylinder 44 but the iit is suiiiciently close so that when the cylinder 44 is suddenly pushed outwardly by the spring 42 it will carry with it the piston 46 and consequently open the valve 33, thus facilitating the flow of oil back to the high compression chamber.V But the movement of the cylinder 40 is brief and when it comes to a stop the spring 34 of the valve 33 returns the valve 33 to its seat by reason of the oil passing around the piston 46. Also, by reason of this relatively loose fit of the piston 46 in the cylinder 44, and the loose lit of the upper end of the valve stem 35 in the opening 36, the valve 33 is permitted to find its seat and thereby make a good close fit to prevent leakage of oil at that point.

With the valve take-up device A substantially filled with oil as will be hereinafter described, it

will be seen that the escape of oil from the high pressure chamber 43 is from the extreme upper end of that chamber around the piston part 30 and between the latter and the inner wall of the movable cylinder 40. Thus if there is any air in the oil it will readily escape under the high pressure referred to, whereas, if the escape for oil was at the lower part of the chamber when the chamber was under high pressure, the air would remain at the upper end of the chamber and would not escape with the oil. The entrance of oil to the high pressure chamber is at the bottom of the piston part 30 where there is not likely to be much air in the oil, this entrance being through the opening 32 which is controlled by the valve 33. Since this valve 33 is open only during the time of low pressure or partial vacuum in the chamber 43, this passage is of no value in permitting the escape of air.

At the lower part of the drawing it will be observed that there is an oil intake passage at 50 and it will be understood that oil under pressure is supplied to this passage by any suitable means, not shown. In tris passage 58 is a metering pin 5| which is made slightly smaller than the passage to permit a definite amount of oil to pass. A spring 52 causes a movement of the pin 5| with the fluctuations in the pressure of oil against it, thus keeping the passage clean. The oil is led to a groove 53 surrounding the bearing and grooves Eil, shown in dotted lines in the bearing and in the cam shaft |2, lead the oil to the interior of the cam shaft where it is carried to other bearings. A conduit 55 with branches 56 carry the oil from the groove 53 to the hollow pins 20 upon which the eccentric sleeves I9 are mounted. This provides lubrication for the sleeves and the rocker arms. A conduit 51 adjacent each of the cylinders 25 carries the oil upwardly to a pocket 58 at the tops of the cylinders. From this pocket openings 59 lead into the upper part of each of the cylinders 25. Thus the oil fed to the pins 20 is carried upwardly through the conduits 51 and delivered to the upper end of the cylinder 25 so that the latter is always filled with oil. The overflow from the pocket 58 falls back into the crank case of the engine and is recirculated.

While I have herein described in some detail a. specific embodiment of my invention, which I deem to be new and advantageous and may specifically claim, I do not desire it to be understood that my invention is limited to the exact details of the construction, as it will be apparent that changes may be made therein without departing from the spirit or scope of my invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A valve take-up mechanism comprising a lever arm, a support, a stationary piston extending downwardly from the support, a spring pressed cylinder movable on said piston and closed at its lower end, said cylinder operating on said lever arm, said piston having a port in its head, a spring closed valve for said port, and means operated by the movable cylinder for controlling the valve action.

2. A valve take-up mechanism comprising a piston having a ported head at its lower end, a spring closed valve for said port, a spring pressed cylinder slidably mounted on said piston and means operated by the movable cylinder for controlling the valve action.

3. A valve take-up mechanism comprising a piston having a ported head at its lower end, a spring closed valve for said port, a spring pressed cylinder slidably mounted on said piston, and means including a hydraulic connection between said valve and said cylinder for controlling the operation of said valve.

4. A valve take-up mechanism comprising a lever arm, an inverted cylinder mounted adjacent thereto, a downwardly extending piston within said cylinder and stationary with relation thereto, a second cylinder within the rst cylinder and operating upon said piston with leakage clearance between the piston and second cylinder, said second cylinder having a closed lower head operating on said lever arm, a spring between the piston and second cylinder, and a valved passage means in the piston head.

5. A valve take-up mechanism comprising a lever arm, an inverted cylinder mounted adjacent thereto, a downwardly extending piston, a second cylinder within the first cylinder and operating upon said piston, a valved passage means in the piston, and means including a hydraulic device forming a connection between said valve and said second cylinder.

6. A valve take-up mechanism comprising a lever arm, a cylinder having a head operating against said arm, a stationary piston extending downwardly into said cylinder and having a port at its lower end, a valve for said port, and means including a hydraulic device forming a connection between said valve and said cylinder.

'7. A valve take-up mechanism comprising an inverted cylinder, a second cylinder moving in the first cylinder, a piston stationary with relation to' the first cylinder and comprising two parts telescoped together, one of said parts extending into ,the movable cylinder and the other of said parts abutting against the closed end of the stationary cylinder and means for supplying oil to both cylinders.

8. A valve take-up mechanism comprising a stationary member having a port therein, a cylinder sliding on said member, a valve for said port, a spring for closing said valve, said valve having a hydraulic connection with the cylinder and having at its opposite end a stem guided by said member, said connection and said stem guiding 5 means being sufficiently loose to permit free seating of the valve.

9. A valve take-up mechanism comprising a stationary cylinder substantially closed at its upper end and open at its lower end, a second cylinder operating in the rst cylinder and having a closed lower end, a stationary piston abutting against the closed end of the first cylinder and extending inside the second cylinder, and means for supplying oil to the stationary cylinder below its closed head and to the second cylinder below the stationary piston.

10. In a valve take-up mechanism, the combination of a supporting cylinder open at its lower end, a working cylinder within the rst cylinder and extending Yoperatively beyond the lower end of the first cylinder, means within the cylinders comprising a high pressure chamber with air and oil escape at the top of said chamber only, and valved passage means in connection with said high pressure chamber.

11. In a valve take-up mechanism, the combination of a supporting cylinder open at its lower end, a working cylinder within the first cylinder and extending operatively beyond the lower end of the rst cylinder, means within the cylinders comprising a high pressure chamber with air and oil escape at the top of said chamber only, valved passage means in connection with said high pressure chamber, and means including a hydraulic device forming a connection between the valve of said passage means and said working cylinder.

l2. A valve take-up mechanism comprising a stationary hollow piston, a working cylinder surrounding said piston and spring pressed relative thereto, a valved passage means between the interior of the cylinder and the interior of the piston and means controlling the valve action.

13. A valve take-up mechanism comprising a stationary hollow piston, a working cylinder surrounding said piston and spring pressed relative thereto, a valved passage means between the interior of the cylinder and the interior of the piston, and means including a hydraulic device forming a connection between the valve of said passage means and said cylinder.

ALFRED MOORHOUSE.

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