US2771065A

US2771065A - Crankcase ventilating means

Info

Publication number: US2771065A
Application number: US381012A
Authority: US
Inventors: Robert H Malcolm
Original assignee: International Harverster Corp
Current assignee: Navistar Inc
Priority date: 1953-09-18
Filing date: 1953-09-18
Publication date: 1956-11-20
Anticipated expiration: 1973-11-20

Description

Nov. 20, 1956 R. H. MALCOLM CRANKCASE VENTILATING MEANS 2 Sheets-Sheet 1 Filed Sept. 18, 1953 7 l Y\IV m z m Q r RN 1. KW Q. m 1 c Q N a. r fifi ww MN 1 m a. 3 m m E MN Wm E Q mm Ma r mm 0 U 0 ATTORNEY R. H. MALCOLM CRANKCASE VENTILATING MEANS Nov. '20, 1956 2 Sheets-Sheet 2 Filed Sept. 18, 1953 MALCOLM ROBERT H.

A TTOR/VEY United States Patent CRANKCASE VENTILATING lVIEANS Robert H. Malcolm, Fort Wayne, Ind., assignor to Interlllational Harvester Company, a corporation of New ersey Application September 18, 1953, Serial No. 381,012

2 Claims. (Cl. 12341.86)

This invention relates to improvements in internal combustion engines and more particularly to an engine crankcase ventilating system for use with internal combustion engines.

It has been conclusively proven that if the gas or vapor, such as water and unburnt fuel, entering the lubricating oil-containing crankcase during the operation of the engine by leakage past the pistons, is not continually removed the lubricating oil will become contaminated by dilution. To obviate this undesirable condition most present day engines are provided with ventilating or scavenging means for continually passing air through the engine crankcase to remove the oil diluents therefrom. Generally the current of air is developed by establishing communication between the crankcase interior and a source of vacuum or sub-atmospheric pressure and is usually accomplished by utilizing the suction existing in the engine intake manifold or the carburetor air intake whereby the condensible vapors, which would otherwise dilute the oil, are withdrawn from the crankcase.

In the majority of crankcase ventilation systems it has been practically impossible to insure a desired, adequate flow of air through the crankcase under all conditions of engine operation since the volume of air flowing therethrough depends on the suction developed by the engine which, in turn, is proportional to the load and speed of the engine which are extremely variable. As an example, under certain engine operating conditions the vacuum developed becomes so high or, stated in another way, the pressure existing in the crankcase becomes so low, when compared with atmospheric pressure, that a substantial amount of oil is unintentionally carried to the exterior of the crankcase where it is lost to the atmosphere or deposited on the exterior of the engine with consequent dirtiness and high oil consumption.

Furthermore, by reducing the pressure in the crankcase area, moisture and abrasive dust-laden air under atmospheric pressure is drawn into the crankcase through various openings therein whereby the lubricating oil is further contaminated and incapable of preventing excessive wear of the moving engine parts. In prior crankcase ventilating systems it has also been virtually impossible to insure the complete separation of the oil particles and mist from the water of the crankcase gas or vapor before the vapor was discharged from the engine when the crankcase interior was subjected to a comparatively low pressure. Consequently, the oil consumption, under certain operating conditions, would be exceessive.

It is, therefore, the primary object of the present invention to provide a new and improved engine crankcase ventilating or scavenging system for efliciently expelling harmful fumes and gases or vapors from the crankcase by maintaining a pressure within the crankcase above atmospheric pressure during the operation of the engine.

Another object of the invention is to provide a crankcase ventilating system for an engine which insures the interception and draining back to the crankcase of any excessive oil that may be carried by or suspended in ice the gas or vapor as well as the condensing of the oil from the gas or vapor before the vapor is expelled from the crankcase to thereby reduce oil loss and lower the engine oil consumption.

A more specific object is to provide a novel passage means for conducting the crankcase vapors to the atmosphere which includes a series of baflies whereby the direction of vapor fioW is changed several times to thereby cause the oil particles in the vapor to separate from the vapor and return to the oil reservoir or sump; the relatively large surface area of the baffles further promotes condensation of the oil from the vapors before the vapors are expelled to the atmosphere.

A still further object is to create a pressure in an engine crankcase above atmospheric pressure by means of an engine-driven air pump in order to induce circulation of the deleterious fumes and vapors within the engine and to expel them to the atmosphere without loss or escape of lubricant from the crankcase.

Still another object is to provide a novel passage construction for directing the crankcase vapors of an external combustion engine to the atmosphere and also for separating any oil from the vapors passing through the passage construction and returning the oil so separated to the crankcase.

The foregoing and other important objects and desirable features inherent in and encompassed by the invention, together with many of the purposes and uses thereof, will become readily apparent from a reading of the ensuing description in conjunction with the annexed drawings, in which,

Figure l is a longitudinal vertical sectional view of an internal combustion engine having the invention embodied therein;

Figure 2 is a sectional view taken substantially along line 2-2 of Figure 1; and

Figure 3 is a plan view of the valve chamber cover dis assembled from the engine.

Referring to the drawings in detail, wherein like reference characters designate like elements throughout the various views, a V-type internal combustion engine is shown which includes a cylinder block structure 10. The cylinder block structure 10 is provided with a pair of oppositely inclined banks 11 which are arranged at an angle of approximately Each bank 11 is provided with four cylinder bores 12 in which pistons 13 are re ciprocably mounted. The pistons 13 are drivingly connected to a crankshaft 14, rotatably journaled in the cylinder block structure 10, by means of conventional connecting rods 15. Attached to the lower marginal edge of the cylinder block structure 10 is an oil pan 16 which is adapted to contain lubricating oil and serve as an oil reservoir for the engine lubricating system.

As best shown in Figure 1, a cylinder head 17 is secured to the uppermost surface of each bank 11. Slidingly mounted in each cylinder head 17 are intake valves 18 for controlling the admission of air and fuel to the cylinder bores 12 from an intake manifold 19. Similarly mounted in the heads 17 are exhaust valves 20 for permitting the flow of exhaust gases from the cylinder bores 12 to exhaust manifolds 21 disposed on the outboard side of each cylinder head 17. As shown in Figure l, a longitudinally extending wall or partition 22 structurally interconnects the lower inner edges of the cylinder banks 11. The lower ends of a plurality of push rods or tappets 23 are slidably mounted in the wall 22 and their upper ends are operatively connected to the intake and exhaust valves 18 and 20. The tappets 23 are actuated by a rotatable camshaft 24 in a conventional manner. The camshaft 24 is rotatably supported by the block structure 10 below the wall 22 and is driven by the crankshaft 14 by means of a pair of meshing gears 25, 26 secured to the camshaft and crankshaft respectively. From the foregoing, it will be appreciated that a crankcase chamber 27 extends substantially the entire length of the engine and is defined by the oil pan 16, the wall 22, and the cylinder block structure 10. Inasmuch as each of the eight cylinder bores 12 opens into the crankcase chamber 27, the gas or vapor which inevitably leaks between the pistons 13 and the cylinder bores 12 during the operation of the engine accumulates within the crankcase chamber 27 to deteriorate the oil contained therein it not efiiciently removed therefrom.

A valve chamber, designated generally by numeral 28 and disposed above the crankcase chamber 27, is partially formed by the wall 22, the upwardly facing, inclined walls 29 of the banks 11, and a pair of vertical, longitudinal spaced end walls 30 and 31. The upper marginal edges of the inclined and end walls 29, 30, and 31 are integrally formed and are formed with an inwardly extending, continuous flange 32, the purpose of which will be explained hereinafter, which outlines an opening 33.

Fastened to the top surface of each cylinder head 17 is a sheet metal cover 34 which serves as an air and dirttight enclosure for the mechanism operatively interconmeeting the upper ends of the tappets 23 and the intake and exhaust valves 18 and 28. As shown in Figure l, the interior spaces 35 of the enclosures are in communication with the valve chamber 28 by means of openings 36 through which the tappets 23 extend.

A valve chamber cover assembly, designated generally by numeral 37, is provided for closing the opening 33. The cover assembly 37 includes a cover 38 which has its central portion bulged or crowned upwardly, as best shown in Figure 2. The peripheral edge 39 of the cover 38 is in the form of a flange which is adapted to abut a gasket member positioned upon the flange 32 when the cover assembly 37 is assembled on the block structure 10. A longitudinally extending, generally rectangular plate 40 has its longitudinally extending edges 41 as well as one end edge welded to the underside of the cover 38. Inasmuch as the plate 40 lies in a generally horizontal plane and the cover 38 has its center bulged upwardly, a longitudinally extending space 42 is formed between the plate and cover. The edge 43 of the plate 40 which is not welded to the cover 38 terminates short of the adjacent end of the cover 38 whereby an opening 44 is formed, providing communication between the valve chamber 28 and the space 42. A semi-circular depression 45 in the cover 38 extends a short distance longitudinally from a point adjacent the edge 41 toward the opposite end. The depression 45 serves as a sprocket, or seat, for receiving one end 46 of a tubular pipe 47, partially shown in Figure 1. A portion of the surface of the pipe 47 abutting the depression 45 is provided with a plurality of apertures 48 which are registrable with a slot 49 in the cover 38 whereby communication is established between the space 42 and the interior of the pipe 47. The valve chamber cover assembly 37 is removably fastened to block structure by means of a pair of bolts 50, 51. Bolt 50, as shown in Figure 1, extends vertically downwardly through the cover 38 and plate 40 and is adapted to be threaded in a threaded recess formed in a boss 52 projecting upwardly from the wall 22. The bolt 51 similarly engages a boss 53 and extends through the cover 38 and plate 40. However, the bolt 51 also extends through the tubular pipe 47 to tightly clamp the end 46 of the pipe to the cover 38 as well as to secure the cover to the block structure 10. From the foregoing, it will be appreciated that three separate and distinct longitudinally extending chambers or passages are formed within the interior of engine, namely, crankcase chamber 27, valve chamber 28, and space 42.

A rotary positive-displacement type air pump 54 is mounted on the timing gear cover 55 which, in turn, is secured to one end of the engine block structure 10. The

' bricated by the engine lubricating system, as shown in copending patent application Serial No. 371,568 filed July 31, 1953, in the name of Robert H. Malcolm, entitled Pump Drive and Lubrication, and assigned to the assignee of the present invention. The pump 54 is adapted to draw atmospheric air from without the engine and discharge the same, under pressure, into the crankcase chamber 27 through an opening 56 in the timing gear cover 55.

As stated previously, it is one of the important objects of the present invention to continuously ventilate the interior of the engine in a particular manner during engine operation and thereby insure greater etficiency in engine performance without experiencing an excessive rate of oil consumption. In operation, the pressurized air flows the entire length of the crankcase chamber 27 in the direction of the arrows during which time it sweeps the deleterious gases and vapors present therein with it. The diluent-laden air then flows upwardly into the valve chamber 28 through an outlet opening 57. It will be noted that the inlet and outlet openings 56, 57 respectively, are provided adjacent the longitudinally spaced ends of the crankcase chamber 27 whereby the scavenging air is caused to pass through substantially the entire length of the crankcase chamber to efficiently maintain the chamber free of the oil. diluents. The scavenging air, after passing through the outlet opening 57, reverses its direction of flow within the valve chamber 28. By changing the direction of air flow any droplets of oil carried by the scavenging air are caused to separate from the air flow and drain back into the crankcase chamber 27 through the opening 57. As indicated by arrows, the scavenging air flows toward the wall 31 and passes through the opening 44 in the cover assembly 37 into the space 42. A body of filtering material 58, such as steel wool or the like, is disposed within the space 42 so that any oil mist or droplets forced into the space 42 will engage the steel wool 58 and be deposited thereon. Eventually, the oil that condenses and accumulates on the steel wool will drain to the valve chamber 28 through the opening 44 and subsequently return to the crankcase chamber 27 through the opening 57. It will also be obvious that direction of air flow is again reversed as it flows toward the exhaust pipe 47 in the space 42 to further cause the oil droplets to separate from the scavenging air. The air which is ultimately discharged to the atmosphere from the space 42 by way of slot 49, registering apertures 48, and the exhaust pipe 47 is substantially free of lubricating oil and is composed principally of noxious products of combustion, such as water, fuel, etc. Furthermore, by maintaining a positive pressure, as distinguished from a sub atmospheric pressure, within the interior of the engine when the engine is operating, any tendency for dirt, dust, etc., to enter the engine through the sealing means between various engine components and subsequently contaminate the engine lubricating oil is defeated.

The embodiment of the invention chosen for the purposes of illustration and description herein is that preferred for achieving the objects of the invention and developing the utility thereof in the most desirable manner, due regard being had to existing factors of economy, simplicity of design and construction, and the improvements sought to be efiected. It will be appreciated, therefore, that the particular structural and functional aspects emphasized herein are not intended to exclude, but rather to suggest such other adaptations andmodifications of the invention as fall within the spirit and scope of the invention as defined by the appended claims.

What is claimed is:

1. In a ventilating system for V-type internal combustion engines or the like comprising a substantially hollow block structure having a pair of upwardly diverging cyl inder banks and a rectangularly shaped, downwardly facing opening, said upwardly diverging cylinder banks forming a substantially V-shaped pocket having an upwardly facing opening, an oil pan secured to said block structure over said downwardly facing opening, a longitudinally extending wall defining the juncture of said banks and the bottom of said pocket, said wall further separating said pocket from a crankcase chamber partially defined by said oil pan and a portion of said block structure, one end of said wall being provided with an opening therethrough for establishing communication between said crankcase chamber and the interior of said pocket; a cover assembly mounted on said block structure over said upwardly facing opening, said cover assembly including a cover having its marginal edges engaging said block structure and a central longitudinal section bulged upwardly, an end portion of said section having a semi-cylindrical depression formed therein, and a substantially horizontal plate secured to the underside of said cover whereby said plate and cover form a longitudinally extending passage, said cover having a pair of longitudinally spaced openings therethrough, one of said openings being located in said depression and being of a larger diameter than the other opening, said plate having a pair of openings therein in alignment with the openings in said cover; means for establishing communication between the opposite end of said passage and the end of said pocket opposite said opening in said longitudinally extending wall; means for introducing air under pressure greater than atmospheric pressure at the end of said crankcase chamber opposite said opening in said longitudinally extending wall; a tubular exhaust pipe having a closed end portion adapted to seat in said depression, said end portion having a pair of diametrically disposed apertures therethrough, one of said apertures being enlarged and being registrable with the enlarged opening in said cover; and means for detachably securing said'cover assembly and the end portion of said exhaust tube to said block structure including a pair of bolts, one of said bolts having a diameter substantially equal to and extendable through a pair of aligned openings in said cover and plate respectively into engagement with said block structure, the other of said bolts having a diameter substantially equal to the other of said openings in said plate and one of the apertures in said tube but smaller than the enlarged opening and aperture in said cover and tube respectively, said last mentioned bolt being extendable through said tube apertures, enlarged cover opening and the plate opening in alignment therewith into engagement with said block structure.

2. The ventilating system substantially as set forth in claim 1, in which said passage contains a body of steel wool for separating oil mist and droplets from air passing through said passage.

References Cited in the file of this patent UNITED STATES PATENTS 1,761,929 McCuen June 3, 1930 2,150,157 Franklin Mar. 14, 1939 2,359,485 Lowther Oct. 3, 1944 2,493,617 Chubbuck Ian. 3, 1950 2,660,987 Doughty Dec. 1, 1953