US1508476A - Fuel-ignition apparatus for internal-combustion engines - Google Patents

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Spt; 16 192%. womm w. RIEHM UEL IGNITION APPARATUS FOR INTERNAL COMBUSTION NGINES Filed Aug. 24. x92:

INVENTOR XDW M z t W M/ A 7TORNE Y5 Patented Sept. 16, 1924.

UNITED STATES "1,508,476 earner- 'oF icE;

WILHELM RIEHM, OE AUGSBURG, GERMANY, ASSIGNOR TO THE FIRM; MASCHINEN- FABRIK AUGSBURG-NUERNBURG, AKTIENGESELLSGHAFT, OF AUGSBURG, GER- MANY, A GERMAN CORPORATION.

FUEL-IGNITION APPARATUS FOR INTERNAL-COMBUSTION ENOINES.

Application filed August 24, 1921. Serial No. 494,884.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 1921, 41 STAT. 1]., 1313.)-

ToaZZ whom it may concern:

Be it known that I, WILHELM RIEHM, a citizen of the German Republic, residing at Augsburg, Germany, have invented certain new and useful Improvements in Fuel- Ignition Apparatus for Internal-Combus tion Engines (for which I have filed application in Germany, July 25, 1919), of which the following is a specification.

The present invention relates to apparatus for the solid injection of fuel into the cylinders of internal combustion engines, andrelates particularly to Diesel or similar engines in which the air in the cylinders is highly compressed before the fuel is injected.'

'In engines'of this type it is common to employ a high pressure pump for injecting the fuel into the cylinder through an atomi'zing noz zle. In such a system, however, considerable difficulty has been experienced by after-flow orgdripping of the fuel into the cylinder after the full injection pressure has been exerted by the pump. Thisdripping occurs due to the fact that the passage between the injection valve and the pressure valve at the pump is filled with fuel which is not forced out during the stroke of the pump'but which subsequently dripsout due partially to the reaction of the flexible walls of the oil passage and chiefly because of compressed air from the cylinder making its way up into this passage. 1

. It has been proposed to place the pressure valve of the pump very close to the injection valve so that the volume of the fluid passage between the two valves is small. Such an arrangement serves onlyto limit the quantity of fuel which will drip into the cylinder, since all the liquid contained in the passage between the two valves will drain out as before. To avoid this it has been proposed to employ the injection valve of the cylinder simultaneously as a pressure valve of the pump. Now .at the starting of the engine the oil passage between the injection valve and the pressure valve is normally filled with air. This air is compressed at the pressure stroke of'the pump piston and expands again at the following suction stroke, thereby forcing back the delivered oil from the passage to the pump casing.

It is accordingly a principal object of the present invention to provide a fuel injection apparatus for internal combustion engines which avoids the above difficulties and at the same time does not interfere in any way with the normal operation of the engine, and which does not require special parts .or otherwise add to the complication or cost of the engine. This is attained by providing besides the combined injection and pressure valve adjacent the cylinder of the engine, a pressure valve at the pump which is operative only during the starting of theengine to prevent a back=flow of the oil from the passage to the pump, and which may be rendered inoperativewhen the engine is running and the oil passage is totally filled with oil.

I have illustrated a preferred embodiment of my invention in the accompanying drawing, which is an elevational view, partly in section and largely diagrammatic, of an engine cylinder and itsfcoope'rating injection apparatus embodying my invention.

Referring to the drawing a indicates the injection pump or similar device for forcing liquid fuel into the engine cylinder 9 through the connecting passage f. At the opening ofthefuel passage f into the engine cylinder there is provided a combined pressure and injection valve 0, here shown diagrammatically as a simple. valve mounted upon a vertical stem and normally 'retained in closed position by means of a coil spring h. This valve, however, may be of any desired type adapted to inject fuel into the cylinder and to be closed at the end of the injection period.

At the starting of the pump the oil pas sage f is filled to a large extent with. air. This air is compressed during the pressure stroke and then expands owing to its elasticity during the suction stroke of the pump, thereby disturbing the regular operation of the pump. To avoid this a pressure valve 0? is located at the pump and this \alve is operative during the starting of the pump so as to prevent the return of fuel from the sure valve should be rendered inoperative. Anyconvenient means may be employed for pump casing. lVhen the engine is running under normal conditions, however, this pres- I this purpose, but I have illustrated a plunclaims without departing from the spirit of ger or a rod 6 having its end which is within-the compression chamber of the pump a inclined upwardly at is and bearing against the lower end of the valve stem (5. Thus when the plunger 6 is moved to its innermost position, asshown, the valve (Z will be; closed. An outward movement of the plunger which may be effected from the exterior of the pump by grasping the outer end of the plunger, causes the base'of the valve stem to ride up on the'inclined portion 7a of the plunger and hold the valve 03 permanently in its open position so that it has no effect upon the flow of the fluid. Valve 0 thus is the only valve which functions during the injection of fuel into the cylinder.

I have illustrated a preferred embodiment of my invention, but it is to be understood that the form of the valves, the various means of control, and the like, may be varied within the full scope'of the. appended the invention.

I I claim: 1. In a fuel injection apparatus for internal combustion engines, the combination with a fuel pump for injecting fuel into the engine cylinder at highpressure and a passage connecting the pump with the cylinder, of a combined injection and pressure valve adjacent the engine cylinder for spraying the pumped oilinto the cylinder and for-preventing return-flow of oil to the passage, and'a pressure valve located at the pump and adapted to be'rendered operative only during the'starting of the engine when the passage containsair, and when so operative serving to prevent the return of oil from the passage into the pump.

rsoaeve 2. In a fuel injection apparatus for internal combustion engines, the combination with a fuel pump for injecting fuel into the engine cylinder at high pressure, and a pas: sage connecting the pump with the cylinder 'of a combined injection and pressure valve adjacent theengine cylinder for spraying the pumped oil into the c linder and for preventing return flow of oil to the passage and a manually operated valve located at the pumpand adapted to be rendered operative only during the starting of the engine, when the passage. contains air, and when so operative serving to prevent the return of oil from the passage into the pump during the suction stroke of the pump, the valve at all times permitting the flow of oil from the pump to the cylinder. I

3. In a fuel in ection apparatus for internal combustion engines, the combination with a fuel pump for injecting fuel into the engine cylinder at high pressure and a pasvalve at all times permitting the fiow of oil from the pump to the cylinder.

In witness whereof I aflix my signature.

DR. WILHELM RIEHM.

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