US2190015A - Oil engine - Google Patents

Description

Feb. 13,1940. c, L, UMM'INS `2,190,015

v o n. ENGINE Filed Jan. 29. 1958 (ffelssze @IWW/Niza Patented Feb. 13, 194C UNITED STATES PATENT vOFFICE o OIL ENGINE Application January 29, 193s, serial No. lsvgss'z 4 Claims.

My invention relates .to oil burning engines of the general type wherein the fuel is burned by the heat of the air compressed' by the piston within the combustion chamber of the cylinder and is more particularly concerned with injection devices for such engines.

The general theory of operation of the present invention is broadly similar to that which characterizes the injector constructions disclosed in my United States Letters Patent Nos. 1,561,913 and 1,762,653, as regards the reciprocation of an injecting plunger in a mixing chamber which communicates with the combustion space of the cylinder through a plurality of ejection ports.

ld 4During the suction stroke of the piston, air is drawn into the combustion space and the plunger is slowly withdrawn to permit a charge of fuel oil to enter the mixing'chamber, While, during the compression stroke, heated air is driven through the ports into the chamber where the oil is entrained and thoroughly mixed. with the air. Near the beginning of the power stroke, the plunger is forced into the mixing chamber and ejects the mixture into the combustion space.

26 In the foregoing construction, the openings through which the fuel passes into the mixing chamber are located adjacent the ejection ports to insure a thorough commingling of the fuel and the air entering the chamber through the'ports,

i 30 and the plunger when in fully advanced position is relied upon to seal the fuel openings and thus interrupt the flow of 'fuel into the mixing cham- 'ber. In small engines, such as those having a bore of approximately four inches and less, the as 'securing of an eiective seal becomes more dimcult because of the reduced size of the parts involved and, accordingly,- the limited areas available for sealing purposes. For example, in an engine having a bore of 3% inches, the base di- 40 ameter of the conical end of the injecting plunger is about 1% of an inch and this base subtends an angle ofu about 40 degrees at the pointed end. Accordingly, with an injecting structure as disclosed in the above-noted patents and assuming an engine size just noted, it is clear` that, if the injecting plunger fails to seat accurately for any reason, the fuel delivery opening will not be completely sealed' off and, hence, even with the plunger in fully advanced position, some drip may be present at the ejection ports. This condition will obviously result in a reduction in fuel econ-- omy, carbonization of the ejection ports, crank lcase dilution, and a smoky exhaust.

u It is,`therefore, one object of my invention to,

devisean oil engine having aninjecting device en through the ports to thereby insure a thorough commingling with the heated air.

'I'hese and further objects of my invention will E@ K be set forth in the following specifications, reference being had to the accompanying drawing, and the novel means by which said objects are effectuated will be definitely pointed out in the claims. i

In the drawing:

Figure 1 is a sectional elevation of a portion of a cylinder of an oil burning engine showing the piston substantially at the end of its compression stroke, and the relation thereto of the fuel in-V 25 jector, ejection ports and the inlet and exhaust valves; and

Fig. 2 is a fragmentaryrsectional view showing a modied arrangement in which the injecting plunger directs the fuel charge towards the ejec-` 30 tion-ports.

Referring to Fig. 1, the numeral l0 designates part ofa cylinder head mounted. in the usual manner on the 'top of a cylinder Il which is provided with a reciprocating piston I2 of a four-@35 cycle engine of the Cummins Diesel type, to which, for purpose of illustration, I have shown the preferred embodiment of my invention applied. The usual air inlet and exhaust valves I3' and H, respectively, are mounted for reciprocat. 40 ing movement on opposite sides of the cylinder axis according to the general relationship shown in Fig. 1, although these valves may be located in other positions Without disturbing the inventive concept involved; -45

While the injecting device hereinafter described is more particularly intended for use with a Cummins type of engine, where a separate mixing chamber is employed to precondition the fuel charge by mixing and vaporization with and 5a by a mass of air delivered into the mixing chamber during the compression stroke of the piston,

the invention is not to be considered as limited in this respect since it generally comprehends the positive cut-oil' of the fuel supply by the ln- 4 f jecting plunger at indicated times during the operation of the engine, and the positive directing of the fuel charges toward the ejection ports to insure a thorough commingling of the fuel charge with the airl which is driven through these ports by the engine piston.

In the form shown in the drawing, the fuel injector comprises a body member or plug I5, an injecting plunger I6 having a cylindrical portion I1 which is reciprocably mounted in a central bore I8 in the plug, and which is further provided with a conical end I9 that is periodically moved into a correspondingly shaped mixing chamber 28 located in a cup-shaped member 2| that is secured to the inner or combustion space end of the plug I5. The chamber 20 is axially aligned with the bore I8 and one or more ejection ports 22 connect the chamber 20 with the combustion space 23 of the cylinder. When the plunger I6 is moved downwardly, the fuel charge is forced through the ports 22 into the combustion space and these ports may belocated and shaped to discharge any arrangement and shape of spray into this space.

The charge of liquid fuel is led from an external source through a passage 24 provided in the plug I5 and this passage merges into an axially aligned valve chamber 25, the junction of the passage and chamber forming a valve seat 26 which is normally engaged and the passage 24 closed by a valve 21. This valve is actuated in a closing direction by a spring 28, one end of which bears against the head of the valve and the opposite end against a spider 29 that guides the movements of the valve and which is seated in the lower end of the chamber 25. A fuel passage 30 leads downwardly from the lower end of the valve chamber 25 and terminates in the wall of the central bore I8 at a point such that the delivery end of the passage will be uncovered when the plunger I6 is occupying the position shown or some higher elevation.

In describing the manner in which my improved injective device coacts with the remaining portions of the oil engine structure, it will be assumed that the piston I2 has drawn a charge of air into the combustion chamber 23 and that the piston is located at some point below that illustrated in the drawing, but is moving upwardly on the compression stroke. It will be further understood that, during the suction stroke of the piston, a charge of fuel oil under pressure, established either by a gravity head or by a pump, has been forced into the mixing chamber 20. This introduction of th fuel charge is effected by the pressure on the fuel line overcoming the pressure of the spring 28 and it is supplied to the chamber 20 at a time when the plunger is substantially occupying the position illustrated in the drawing.

During the compression stroke, the temperature of the air increases rapidly and air is driven into the mixing chamber` 20 through the ports 22 to thoroughly mix with and vaporize the o il therein, as described more particularly in the above-noted patents. Shortly before the. piston reaches top center on its compression stroke, the plunger I6 is driven downwardly by'an-y -suitable means to eject the entire mixture of fuel and air from the chamber 23 into the combustion space.

The delivery end of the fuel passage 30 may be located generally as illustrated, or in other words, so that the fuel charge will be directed toward the ports 22 to insure a thorough com-A mingling of the charge and air. This action is also facilitated by the impact of the fuel charge against the conical surface of the plunger as the latter moves towards the ports. Further, it will be particularly observed that the delivery end of the passage 30 is remote from the ports 22 and that it is sealed by the cylindrical portion of the plunger during injection.

Any drip which might otherwise occur at the ports 22 is, therefore, completely prevented, while still obtaining such a thoroughness of mixture and entrainment of the oil with the air that any tendency toward stratification of the mixture in the mixing chamber is avoided. Otherwise, some of the fuel might be forced into the combustion chamber in a liquid state, and this condition would cause momentary high pressures, late combustion of part of the charge, a decrease in power, carbon deposits and an unequal distribution of thecharge in the combustion chamber. The present construction is entirely free of the foregoing `operating faults and retains the advantage of the structures disclosed in the noted patents as regards a thorough pre-conditioning of the fuel-air mixture in the mixing chamber.

It will be understood that the spring 28 is sufficiently strong to maintain the valve 21 closed during the period of the cycle when the plunger is retracted, but the valve is not subjected to fuel pressure. Slow drip of the fuel is thereby prevented during this operaive phase of the device.

In Fig, 2 is illustrated a fragmentary view generally similar to that shown in Fig. 1, but embodying a position of the fuel supply passage 3l, corresponding to the passage 30, that does not direct the fuel charge towards the ejection ports 32. The securing of this result is attained by causing the charge to impact against the conical end of the plunger 33 which acts as the directing element.

In either of the modifications, it will be partcularly noted that the pointed end of the plunger i6 exercises a directive effect on the 'air forced through the ejection ports such that the air is caused to divide and wash over the surface of the conical end of the plunger, thereby insuring a better distribution of the air in the mixing chamber and eliminating any possibility of a considerable portion of wet fuel adhering to the surface, or of being unmixed with the heated air. An homogeneous fuel-air mixture is thus assured.

I claim: -f

1. An injecting device for an oil burning engine comprising-'in combination, a body having a chamberprovided with one or more ejection ports and a passage for supplying the chamber with fuel 'under pressure, and an injecting plunger reciprocable in the body to alternately provide for the delivery of fuel to the chamber and to discharge the fuel through the ejection ports, the plunger having a surface located to direct toward the ejection ports the fuel charge issuing from the delivery port of the passage when the plunger is in retracted position and another surface for sealing the delivery port during injection.

2. An injecting device for an oil burning engine comprising in combination, a body having a cavity terminating in a conical chamber provided with one or more ejection ports and a passage for supplying the chamber with fuel under pressure, the delivery port of the passage terminating at the surface of the cavity, and an injecting plunger having a portion fitting the cavity and a conical end, the portion being reciprocable in the cavity to alternately uncover and seal the delivery port and to discharge the fuel through the ejection ports by the conical end, the conical end being located substantially opposite the delivery port when the cavity'iltting portion of the plunger is in uncovering position to direct the 5 issuing fuel charge toward the ejection ports. 3. An injecting device lfor an oil burning engine of the piston type comprising a conical mixing chamber having a supply port communicating with a source of liquid fuel under pressure y '10 and one or more ejection ports providing communication with the combustion space of the engine cylinder and through which air is forced during the compression stroke of the piston to mix With'fuel delivered into the chamber, and an i6 injecting plunger having a conical end retractible in the chamber to provide for the delivery of fuel thereto and advanceable to discharge the mixture through the ejection ports-into the cylm inder, the surface of theconlcalfend being loport toward the ejection ports when the plunger is in retracted position and the ejection ports being located to direct air forced into 'the chamcated to deflect the fuel issuing from the supply e ber by the piston against the conical end to distribute the same.

4. An injecting device for an oil burning engine of the piston type comprising a body having a chamber provided'with one or more ejection ports and a passage for supplying the chamber with fuel under pressure, the ejection ports pro" vlding communication with the combustion space of the engine cylinder and through which air is forced during the compression stroke of the piston to mix with fuel delivered into the chamber, and an injecting plunger reciprocable in the body to alternately provide for the delivery of fuel to the chamber and to discharge the fuel through the ejection ports, the plunger having a surface located to direct toward the ejection ports the fuel charge issuing from the delivery port of the passage when the. plunger is in retracted position CLESSIELCUMMINS.

Images