US1588879A - Starting valve for internal-combustion engines - Google Patents

Description

Juhe 15 1926.

J. F. ENGLERT STARTING VALVE FOR INTERNAL COMBUSTION ENGINES Filed August 24, 1921 1 NVENTOR MI'M A TTORNE Y$ Patented June 15, 1926.

UNITED STATES PATENT OFFICE.

JOHANN FRIEDRICH ENGLERT, F NUREMBERG, GERMANY, ASSIGNOR TO THE FIRM MASCHINENFABRIK AUGSBURG-NUERNBURG, AKTIENGESELLSCHAFT, OF AUGS- BURG, GERMANY, A CORPORATION OF GERMANY.

STARTING VALVE FOR INTERNAL-COMBUSTION ENGINES.

. Application filed August 24, 1921, Serial No. 494,914, and in Germany November 5, 1918.

I (GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 1921, 41 STAT. L, 1313.)

The present invention relates to apparatus for starting internal combustion engines, and

relates particularly to Diesel or similar engines in which the starting operation is ac- 6 complished by means of compressed air.

It is necessary that apparatus be provided in conjunction with engines of the above type by means of which they may be started to rotate in either a forward or reverse di- 10 rection from any position of rest. In starting multi-cylinder engines the air admission to successive cylinders overlaps so that the engine may be started to rotate from any possible position of rest. As a result, compressed air at a high pressure must be admitted to each cylinder throughout a large proportion of its stroke, and consequently the air exhausted from the cylinder is at a pressure very materially higher than atmospheric. It is thus seen that a large quantity of air is ordinarily required for each working stroke of the piston, and an appreciable amount of energy contained in the compressed air is wasted in the high pressure exhaust. A correspondingly low efliciency of the starting apparatus results.

It is accordingly an object of the present invention to provide an apparatus for starting internal combustion engines of the above type, in either the forward or reverse direction from any position of rest, in which it is possible to utilize the energy contained inthe compressed air to a greater extent than has heretofore b.een done;

It isnlsdafibbject of thepresent invention to provide an apparatus of the above type by means of which the engine piston may be subjected to the maximum pressure from the compressed air reservoir during substantially the entire length of its stroke when the engine is first set in motion, and in which it is possible to cut ofi the supply of a compressed air earlier in the stroke as the speed of the engine increases, thus obtaining the effect of the expansion of the compressed air within the P cylinder and utilizing a smaller total quantity of air on each stroke.

I have illustrated a preferred embodiment of my improvedstarting apparatus in the accompanying drawing, which is a diagrammatic view, partly in perspective and partly n section, showing a starting device embodymg my invention.

In said drawing, 1 indicates the body of the engine cylinder and a indicates the housing which incloses the air admission valve. This valve is formed with a piston c at its upper end and is held normally in closed position by means of a coil spring I) surrounding the valve stem. The valve serves to con- 0 trol the orifice 1' which 0 ens into the engine cylinder and which is in communication with a compressed air line 01 leading from an air reservoir or other convenient source.

The space abovev the piston 0 opens into a 5 pipe e having two branches communicating respectively with two slide valves f and g. The valve 9 communicates with an actuating valve is by means of pipe i, while valve 7 is similarly connected to a valve Z through the 7 connecting pipe h. The valves is and Z are connected to the compressed air line (i by means of pipe r and g, respectively. Each of the valves k and 1 consists of a body member sliding within its housing and normally held in its outermost position by means of a coil spring placed within the housing. A fluid passage traverses the body member of the valve as indicated in dotted lines.

The valve stems project through the outer g0 ends of the housings as indicated at m and n and engage respectively with cams o and ya ri gidlyamounted-upon arshaft qlvhen W the shaft 8 is rotated in the direction indicated, the cam 17 depresses the valve stem 35 n to its maximum extent and causes the upper end of the fluid passage (indicated in dotted lines) to register with the pipe 9. Compressed air will thus flow from the line d through pipe 9 and the body of the valve Z, into the connecting pipe h. At the same time the cam 0 is in such position that the valve stem m is not depressed and valve 76 serves to connect the pipe 15 with atmosphere, as shown. Further rotation of shaft 8 in the direction indicated by the arrow will bring the high portion of the cam o to bear against the valve stem m, and-will depress it, serving to connect pipes 1' and i in series and permit a flow of compressed air-to-the 1 0 valve g, the valve Z havin simultaneously been shifted so that pipe 5 is connected to atmosphere.

.In cooperation with valves f and 9 there is provided a cam shaft a rotating in fixed relation to the crank shaft of the engine and bearing cams u and m, which engage with the valves f and g respectively. Cam u is circular in form around the larger portion of its periphery and serves to maintain the body of-the valve f depressed to its innermost position during the greater part of each revolution. A portion of the cam surface, however, is flattened off at u and, when the follower f provided on the valve body contacts with the flattened portion u i of the cam, the valve body is forced out- .sented to the follower f.

wardly due to the pressure in the pipe h and allows compressed air to pass down through pipe 6 into the space above the valve piston c. The force of this air depresses piston c and effects an opening of the air valve, which is followed by inrush of compressed air from the line (1. It is understood that during this operation the cam 12 depresses the valve stem it. After the shaft 1) has rotated so that the follower f rises again upon the circular portion of the cam u, valve f will close the inlet into pipe 0 and shut off the air pressure which holds valve (1 in open position. V

Gama: is identical with cam u except that the flattened portion on occupies a substantially smaller proportion of the periphery of the cam than does the flattened ortion u. As a result, during each revolution of the cam shaft 1:, the valve 9 may remain in' open position a length of time which is correspondingly shorter than that of valve 7.

In operation the cam shaft 8 is turned by hand to depress the valve stem 12., so that compressed air from line-d is free to flow thru pipe 9 and connecting pipe 1:. to the inlet port of the valve f. Motion is then imparted to the engine suflicient to turn the cam shaft '0, to such a position that the flattened porion u of the cam u will be pre- In this position valve 7 will be opened and compressed air will be admitted to the cylinder 1 to act upon the piston during its downward strokes.

' The flattened portion of the cam subtends a suificient angle to keep the valve g open during substantially the entire stroke of the plston, and this furnishes ample power for startin the engine from rest. After the engme as begun to turn under the influence of the compressed air, the shaft 8 may be tnrned to such a position-that the raised portion of the cam o engages with the valve stem m and connects valve 9 in operative relation. instead of valve 7. 'v rotates and brings the flattened portion into contact with the follower 9' prov1ded on the body of the valve 9 compressed As the shaft small, the valve a will remain open during only a fraction of thetime required for a complete stroke of the piston. The impulse imparted by the compressed air during this portion of the stroke, together with the force subsequenly exerted due to the expansion of the air within the cylinder, is sufficient to naintainthe engine in motion until ignition is effected andthe engine begins to operate under its own power.

I claim 1. Apparatus for starting internal combustion engines, comprising the combinationwith the cylinder of an internal combustion engine, of a valve for admitting starting air into the cylinder, and pneumatic means for actuating said admission valve, the said means comprising a source of air under pressure, a ower driven shaft, and a pair of control evices actuated by said shaft and in turn serving to admit air from said source to said valve to actuate the same, one of these devices being actuated from the shaft to maintain the admission valve open for a longer other, and means for rendering these devices alternately operable.

2. Apparatus for starting internal coinbusti-on engines. comprising the combination with the cylinder of an internal combustion engine, of a valve for admitting starting air into the-cylinder, and pneumatic means for actuating said admission valve, the said pneumatic means comprising a pair of valves, means for actuating these valves, the said means operating to hold one of the valves open longer than the other, and means for rendering the valves alternately effective to actuate the admission valve.

3. Apparatus for starting internal combustion engines, comprising the combination with the cylinder of an internal combustion engine, of a' valve for admitting starting air into the c linder, and pneumatic'means for actuating said admission'valve, the said pneumtic means comprising a pair of valves, a cam for actuating each valve, one of these cams having a wider angle openlng than the other, and means for rendering the valves of these ems having a ,wider angle opening period than the than the other, and pneumatic means for rendering the valves and their associated cams alternately operable.

5. Apparatus for starting internal combustion engines, comprising the combination with the cylinder of an internal combustion engine, of a valve for admitting starting 8.1! into the cylinder, and pneumatic means for actuatin said admission valve, the said pneumatic means comprising a pair of valves, a power driven cam for actuating each valve, one of these cams having a wider angle opening thanv the other, and manually controlled pneumatic means for rendering the valves and their associated cams alternately operable.

6. Apparatus for starting internal combustion engines, comprising the combination with the cylinder of an internal combustion engine, of a valve for admitting starting. air into the cylinder, pneumatic means for actuatin the admission valve comprising a pair 0 valves for admitting compressed air against one face of the valve to open the same, and a power driven cam for actuating each'of the pair of valves, one of these cams having :a wider angle opening than the other, and a second pair of valves for controlling the flow of compressed air to the first pair of valves, the second pair of valves being alternately operable and in turn -ren-' derin the valves of the first pair alternately opera ls.

7. -Apparatus for starting internal combustion engines, comprising the combination with the cylinder of an internal combustion engine, of a valve for admitting starting air into the cylinder, a pair of valves for admitting compressed am against one face of the admission'valve to open the same, a power driven shaft, a pa1r of cams on the shaft, one for actuating each of the pair of valves, and one of these cams having a wider angle opening than the other, a valve for controlling the flow of compressed air to each of the said pair of valves, and manually operated means for actuating the said control valves in alternation whereby the pair of valves are alternately operable to control I the flow of air for actuatlng the admission valve.

8. Apparatus for starting internal combustion engines, comprising the combination with the cylinder of an internal combustion engine, of a conduit containing air under pressure and leading to the engine cylinder a'valve for controlling the admission 0 air from the conduit into. the cylinder, a pair of valves for admitting air from the conduit against one face of the admission valve to unseatthe same, separate means for intermittently actuating these valves, one

of said means holding its associated valve open for a longer period than the other valve is held open, a second pair of valves for controlling the flow of air from the conduitto'the first pair of valves, and means for opening the second pair of valves in alternation whereby the first pair of valves are alternately operated and air is admitted toi'the cylinder for long and short periods successively.

In testimony whereof I aflix my si aturc. JOHANN FRIEDRICH ENGL RT.

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