US2099278A

US2099278A - Internal combustion engine

Info

Publication number: US2099278A
Application number: US532397A
Authority: US
Inventors: Schimanek Emil
Original assignee: Individual
Current assignee: Individual
Priority date: 1930-04-25
Filing date: 1931-04-24
Publication date: 1937-11-16
Anticipated expiration: 1954-11-16

Description

Nav. 16, 1937. E. SCHIMANEK 2,099,278

- I INTERNAL COMBUSTION ENGINE Filed April 24, 1951 N 2 Sheebs-Sheet 1 llllllll ll|l /JOM mwwm 46;

, Nov. 16. 1937. E. SCHIMANEK INTERNAL COMBUSTION ENGINE 2Sheets-Sheet Filed April 24. 1931 Patented Nov. 16, I937 2,099,278 INTERNAL-COMBUSTION ENGINE limil Schimanek, Budapest, Hungary Application This invention relates to internal combustion engines which work with fuel injection, more particularly Diesel engines. The known internal combustion engines with fuel injection work either with direct injection of fuel into the cylinder or else with injection of fuel into a preliminary chamber that precedes the working cylinder. In both cases the fuel passes into the working cylinder in an atomized but still liquid 0 form. This method of injecting fuel has disadvantages, which render the employment of such engines, particularly in the case of small engines, impossible for high speeds of revolution. These disadvantages consist primarily in the fact that on thepne hand the atomization and regulation of the quantities of fuel to be ,introduced, particularly in the case of small motors, are diflicult to efl'ectat ahigh speed of revolution, and

on the other hand in the fact that delayed ignitions occur. At the high pressures and the high fact that the fuel, before it burns, must be converted from the form of a liquid to that of a vapour, the quantity of heat requisite for this purpose being taken from the highly compressed air in the cylinder.

Now the object of this invention is to obviate these disadvantages in a reliable manner, and the invention consists in the fact that the heating of the liquid fuel under pressure on its way to the working cylinder is eflected. under such circumstances that the temperature .of preheating approaches as nearly as possible the vaporization temperature at the existing pressure, but cannot exceed the latter temperature, so that the maximum preheating of the fuel, which is practicable without risk of evaporation before injection is attained.

According to the invention this result is obtained by heating the fuel under pressure by means of a heating device with automatic regulation in dependence upon the vaporization temperature corresponding to this pressure, or the 50 critical temperature, in such a way that the vaporization temperature is nearly reached but is -not exceeded, thereby attaining the maximum preheating of the fuel that is possible withoutthe risk of vaporization before injection.

55 By this invention it is made possible to intro April 24, 1931, Serial No. 532,397 In Austria April 25, 1930 '18 Claims. (01. 123-32) L duce the fuel into the cylinder at a hi her pressure and at a higher temperature than corresponds to'the critical pressure and the critical temperature, which is mostly already reached at pressures lower than that-corresponding to the 5 injection pressure, this being effected according to the invention by automatically regulating the heating effect in such a way that the formation of vapour cannot occur. The invention thereby also furnishes a means of successfully utilizing fuels that are dimcult to vaporizefor operating injection internal combustion engines, since the quantity of heat requisite for vaporization is already supplied to the fuel before injection.

Such heating has primarily'the following advantages:--

(1) The volume of the liquid is increased by the heating, as a result of which both the fuel pumps and'the holes inthe injection nozzles are enlarged, and the operating, both asregards the accurate functioning of the pump and as regards the choking of the nozzle holes, is improved; I

(2) Owing\to the fact that part of the fuel,

upon being injected into the cylinder, evaporates in consequence of'the fall of pressure occurrin on injection, the atomization is improved;

(3) Owing to'the formation of vapour, .and also owing to the better atomization, the combustion is promoted and the duration of com fbustio'n shortened.

' Bysuch a process the result is also obtained that motors working with fuel injection (Diesel engines) can be operated at a higher speed of revolution than they could without preheating.

The above-mentioned advantages may become still more marked the more highly the fuel to be injected is preheated under pressure. The limit of the liquid.

The formation of vapour can be reliably prefuel itself is employed as the heating medium,

and the latter is at the same or a somewhat vaporization. of t e a ter y b r i b y p elower pressure than the fuel to be heated, the

vented by utilizing the vaporization of the liquid employed as the heating medium-in this case the same liquid as the fuelfor regulating the heater (electrical heater, lamp heater or the like), whereby a further rise of temperature is. guarded against, or the vaporization temperature of the liquid heating medium, and at the same time therefore vthe .somewhat lower temperature of the liquid fuel, is permanently secured, provided the heater yields sumcient heat, that is to say, provided the heater is designed for the maximum load.

The said advantages may however also be utilized to the utmost limit, without the employment of a heat-transmitting medium, by effecting the regulating of the preheating by means of the vapour pressure or. the vapour density, or by the temperature of the fuel (liquid or vapour) to be injected, the various magnitudes being utilized either singly or in any desired combination.

The utilization of the fuel vapour, the vapour density or the temperature of the preheated fuel has the advantage that the desired regulating can be reliably obtained even in the case of those fuels for which, as mostly occurs in practice, the thermal properties (relationship between vapour pressure and temperature'and so on) are unknown. I

If the vapour pressure is to be employed for regulation, the heatingwillaccording to the invention be carried out in such a way that the liquid, during the heating, is warmer at the surface or in the neighbourhood of the surface than at the deeper parts of the liquid. The

vapour that forms in the upper portion of the liquid is then utilized for regulating the heating, while from the lower and cooler portion of the liquid the pump sucks in the fuel to be injected.

Various forms of the process according to the inventionare illustrated by way of example in the accompanying drawings, in which Figurel shows for purposes of comparison the known means for injecting fuel into the working cylinder,

Figures 2 to 9 show diagrammatically in section'al elevation various examples of construction of the invention.

In the known fuel injection device illustrated\ in Figure 1, the liquid fuel is drawn in by suction by a fuel pump I through a suction valve 2, and is sprayed through a delivery valve 3, a pipe 4 and an atomizing aperture 5 into the cylinder 6, in which there moves a piston I.

The injection aperture 5 is controlled by a valve 9, which may be constructed as the delivery valve of the pump. The injection valve may however alternatively be non-mechanically controlled. Substantially the same arrangement may be employed in :the case of preparatory chamber injection. In the example of construction shown in Fig. 2 the pipe 4, which leads from the pump I into the cylinder-and in which the fuel is subjected to pressure, is so strongly preheated, electrically -,fo r example, by means of a heating coil 8, that .iipon the pressure being relaxed by the opening of the injection valve 9, the evaporation of the quid fuel is brought about to an extent depend- Y nt upon the fall of pressure and upon the preheating.

Preferably the arrangement is such that the delivery valve 3 of the pump closes the pipe l at g R the inlet point, and the injection aperture is con-' q trolled. by a separate valve 9. This prevents d s- 'The compressor piston turbances occurring owing to any excessive preheating of the liquid fuel in the fuel pump.

The heating apparatus 8 is adjustably constructed to enable the temperature of preheating to beregulated in accordance with existing requirements. Thus for example if electrical heating from a source of energy 8a is employed, the intensity of the heating may be so connected with the engine governor 8b, operatively connected with a variable resistor 80, that at higher governor positions, that is to say, at low loads, the heating is less efiective than at lower gover-l nor positions, that is, at greater loads, since in the former case less liquid fuel has to be preheated than in the latter case. It is also advantageous to employ a pump I, of which the pressure can be regulated manually or automatically. Between the fuel pump I and the cylinder 6 is arranged a pump, compressor .or the like I2, I3, in which the liquid fuel preheated in the pipe 4 under pressure enters through the valve I as a mixture of liquid andv vapour, while owing to the relaxation of pressure when the valve I0 opens, a portion of the fuel is vaporized. This mixture of liquid and vapour is subjected by the compressor piston I2 to a compression by which so much heat is supplied to the mixture of liquid and vapour that the liquid still contained in the mix ture is wholly, or at least to some further extent, vaporized by the relaxation of pressure. Not only does this operation provide sufflcient heat for the further vaporization of fuel not yet'vaporized but also insures, upon admission of the fuel to the cylinder, a better atomization of the drops of liquid still present after the first atomization. I2 delivers the fuel through the aperture of the valvethat acts as a pressure-relieving aperture into the cylinder 6.

Figure 3 shows a constructional example in which the compression of the liquid already partially vaporized by the heating of the liquid and,

inder in a pre-compnessed condition. In this constructionalform, as the compressor piston I2 descends, at first air flows through the pipe It into the cylinder, and then, when the piston uncovers the connection leading to the valve I0, there flows in a mixture of liquid and vaporizedfuel, which is then compressed by the piston I2, and delivered through the valve II, the pipe connection I I and the injection aperture 5 into the cylinder '6. The valve I1 may even be omitted, its place as a delivery valve for the compressor being taken by the valve 9. Atomization upon relaxation of pressure in,the cylinder is thus promoted by the expansion of the air compressed with the fuel. This form of the process also renders possible a lower liquid pressure on the delivery side of the fuel pump and a lower preheating of the liquid fuel as well as the adoption of smaller injection velocities andpressuresffor the injection of the fuel into the cylinder.

Figure 4 shows a constructional example with I pipe 4 to the injection aperture, but through the medium of a liquid-which is provided in a chamber surrounding the tube 4. This liquid may advantageously be the same liquid asthe fuel employed. Should some other liquid be employed as a heating-medium, the boiling points of this liquid corresponding. more various pressures must be known.'.

The chamber I1 is closed at the top by a piston II or by some other movable member, which is subject to the pressureof a spring |,8a, and by means of a lever l9, which can rotate about a point 20, aotuates a... regulating device 2|, by which the intensity of the heating means '8 is influgnced. At'the bottom of the chamber "'1' is provided a shut-oif member 22, by which any heating liquid that has escaped'by leakage or otherwise can be replaced. The piston I of the fuel pump is so constructed that during the suc- -tion stroke it is moved by the cam Id of a cam disc lo and a lever lb, but during the compression stroke is under the influence ofa spring la, the liquid pressure produced being thereforeunambiguously determined by this spring. This point, there is evolved in the chamber II, at the liquid pressure determined by the pressure of the spring Illa, vapour, which moves the piston l8 and diminishes the intensity of the heating until the temperature. of the .heating medium in the chamber I1 is kept steadily at the level of the vaporization temperature. This temperature is therefore steadily maintained in the chamber 11' independently of whether more fuel or less fuel isiiowing through the tube 4 to the cylinder. This fuel is therefore always heated right up to that temperature which corresponds to the vaporization temperature of the heating. liquid, which may be liquid fuel, at the pressure prevailing in the chamber Figure 5 shows a constructional example in which a superheatingof the fuel ora vaporization thereof is prevented by the fact that the heat transmitted to the liquid heating medium by excess heating generates vapour, which is condensed on a cooled surface 23a. The heating device 8 is h re represented as an electrical device, and by eans of the heating liquid in the chamber l'l'j heat is transmitted to the liquid fuel flowing'through the pipe 4. The pressure in the chamber I1 is adjusted by means of the piston l8 and the spring l8a, as explained in connection with the preceding example, and is harmonized with the spring la. The heat transmitted to the liquid heating medium by overheating is here removed owing to the a fact that the vapour produced by overheating passes through the pipe/Ila into a cooling vessel 23, where the vapour is condensed. There will always heated to one and the same temperature, quite independently of the load.

Figure 6 shows a constructional example in which, when employing the fuel itself as a heating liquid, ,the pressure in the chamber IT is connected with that in the tube 4 throughthe medium of the piston 18 in such a way that upon one side of the piston l8 there acts the pressure in the chamber 4, and on the other side of the piston there act'the pressure in the chamber l1 and the pressure of the spring 18a, whereby the pressure in the chamber H is kept lower than that in the tube 4.

Figure "I shows the solution, in which in the chamber l1 and in the' chamber 4 the same pressure is established by connecting these two chambers with'one another, in which case the pump delivers into a chamber, from which the pipes 4, I11) and 23a branch off. The vapour generated in the chamber I1 is here condensed in the tube I11: and 23. In this case the pump I may be moved positively even during the delivery stroke instead of by a spring.

Figure 8 shows a constructional example of a step-by-step preheating of the fuel, which is regulated by the pressure of the vapour.

The pump. draws fuel by suction out of the tank 3| and delivers it into the first heating vessel 32. This vessel is heated by an electrical heating device 33 on the cylindrical surface. The regulating of the heater is effected by means of a piston 34, which co-operates with the vessel 32, and which, by meansof a lever 36 under the action of a spring 35, actuates electrical regulating means 31.

To the vessel 32-is connected at the bottom'the suction pipe of a pump 38; which draws in fuel from the bottom of the vessel 32 and delivers it into the heating vessel 39, which is heated by an electrical heater 40, this heater being regulated by a piston 4| 'through the medium of a lever 43' acted upon by a spring 42, and an electrical regulating device 44. q To the bottom of the vessel 39 is connected the suction pipe of a pump 45, which'draws the fuel out of the lower portion of the vessel 38 and delivers it directly or through a mechanically con trolled .val e 46 intciv the motor cylinder 41. In

the former case, that is with direct delivery, the valve 46 is omitted, and the pump delivers the fuel through an open nozzle 48 into the cylinder, in which case however the delivery valve of the pump is positively controlled.

'I'he method of operation of the heat-regulating means is as follows:

As soon as the temperature in the heating ves- .sel 32, owing to the action of the heater, has ex-' ceeded' the temperature corresponding to the vapour pressure, which is uniformly determined by spring pressure and by the diameter of the perature corresponding to the pressure established in the vessel by the force of the spring is maintained.

The form of the tank, which is a high vertical cylinder, and the arrangement of the heater in the cylindrical surface, have the result that the liquid in the neighbourhood of the surface will be a few degrees warmer than in the lower portion. The formation of vapour is therefore limited to .the uppenportion of the liquid, while from the lower portion, or infact from the lowest point,

liquid is drawn out by the suction of the pump 38. The pressure in the tank 32 and in the tank 39 can be regulated at will owing to the design of the

springs

35 and 42 respectively.

The pump 45 sucks liquid from the vessel 39 under a lower pressure than that at which the injection is to occur.

It will be obvious that either direct injection or preparatory chamber injection may be employed.

The speed of revolution of the pump 45 is determined by the speed of revolution of the motor 41 and the number of strokes per cycle, while the

pumps

38 and 30 may be operated at any convenient speed of revolution. The pump is thus operated in timed relation with the engine, and in predetermined relation with valve 45 so that such pressure variations as occur in chamber 39, fall within a comparatively limited range. The resultant pressure rises in response to the superadded pressure of generated vapor and causes actuation of the control device 44.

The heating of the fuel may alternatively be carried out in a single stage, by the aid of a single heating vessel." In this case the pump 30 and the heating tank 32, together with the equipment thereof, are omitted and the 'pump 38 sucks directly out of the fuel tank 3|.

If the regulating of the heater or of the fuel preheating is not effected by the vapour pressure but by the vapour density, for the purpose of obtaining a preheating approximating to the critical temperature of the fuel, the regulating of the heater may be obtained with a suitable boiler water level protection apparatus, such for example as that shown in Fig.9. The-heating right to the critical point has the advantage, in addition to those mentioned above, that at, the critical temperature "the liquid volume is a maximum, and at this temperature the liquid and the vapor have the same volume, that is to say, the accurate measuring of the quantity of fuel sucked in by the. pump cannot be disadvantageously affected by the pump sucking in a mixture of vapor and liquid. The regulating of the heating when the critical point is to be reached may be carried out on the basis of the principle that at this temperature the vapor and the liquid are of the same volume and of the same density. Any automatic boiler water level regulating device can therefore be used as described above, the action of these devices in general being based upon the fact that vapor and liquid are of different specific gravities, or

influence the thermoconductivity or the electrical resistance differently.

In Figure 9 is shown as a constructional example a device which acts by electrical means.

In the heating vessel 50, in which the liquid level is secured by means of a discharge pipe 5|, an electrical conductor or an electrical resistance 52 is lodged in the liquid space' and a second electrical resistance 53 in the vapour space of the vessel. Both resistances are made of a material of which the electrical resistance changes according to the nature or density of the medium in delivered by a source of current 59 flows through the heating wire 50 of the vessel 50. As soon as the condition in the heating vessel has reached the critical point of the fuel, the resistances 52 and 53 become equal inmagnitude. The bridge 55 then carries no current, and the relay 51 allows the contact lever 6| to fall, whereby the contact 58, and therefore the heating circuit are interrupted.

What I claim is:--

1. A method of operating internal combustion engines with liquid fuel injection, particularly Diesel engines, comprising supplying liquid fuel to the engine 'under pressure, heating the liquid fuel while on its way to the engine cylinder under pressure through an interposed liquid between the source of; heat and the liquid fuelto be heated, the said liquid forming the means of transmitting heat from the source to the fuel, regulating the heating of the fuel to be injected to maintain the temperature thereof interme- 'diate its vaporizationtemperature under pres-- sure before injection and its vaporization temperature at the lower pressure within the cylinder to thereby maintain the fuel in the liquid state prior to its introduction into the cylinder and to provide "sufficient heat in the fuel so that it is vaporized as a result of the heat contained therein when introduced into the cylinder at said lower pressure, and then injecting the fuel into the engine cylinder. 7

2. A .method of operating internal combustion engines as claimed in claim 1, further comprising interposing some of the fuel-liquid, as a means for transmitting heat, between the source of heat and the liquid fuel to be heated. I

3. A method of operating internal combustion Y 4. A method of operating internal combustion engines as claimed in claim 1, further comprising utilizing the vapour of the heat-transmitting liquid as a means for automatically regulating the heating of the liquid fuel, the said vapour exerting a compensating'action by its condensation.

5. A method of operating internal combustion engines with liquid fuel injection, particularly Diesel engines, comprising supplying liquidfuel to the engine under pressure, heating the liquid fuel while on its way to the engine cylinder under pressure, the heating \of the liquid fuel being eflected in such a manner that the fuel becomes warmer at and near the surface than lower down, and utilizing the vaporization of the liquid at the surface for regulating the heating of the fuel to be injected to maintain the temperature of said fuel intermediate its vaporization temperature under pressure before injection and its vaporization temperature at the lower pressure withinthe cylinder to thereby maintain the fuel in the liquid state prior to its introduction into the cylinder and'to provide sufllcient heat in the fuel so that vaporization results because of the.

heat contained therein when introduced into the cylinder at said lower pressure, and then introducing the fuel into the engine cylinder.

- 6. A method of operating internal combustion engines with liquid fuel injection, particularly Diesel engines, comprising supplying liquid fuel to the engine under pressure, heating the liquid fuel while on its way to the cylinder under pressure to a regulated temperature intermediate its vaporization temperature under pressure and its vaporization temperature at the lower pressure within the cylinder, the heating of the liquid fuel liquid fuel being -withdrawn from the lower part of the said vessel by-a fuel pump, for injection into the engine cylinder,at a temperature that is a few degrees below the saturated vapour teming in the heating vessel. I

perature corresponding to the pressure prevail 7. A method of operating internal combustion engines with liquid fuel injection, particularly Diesel engines, comprising supplying liquid fuel to the engine under pressure, heating the liquid fuelwhile on its way to the cylinder under pressure to a regulated temperature intermediate its vaporization temperature under pressure and its vaporization temperature at the-lower pressure within the cylinder, the heating of the liquid fuel being effectedin such a manner that the fuel becomes warmer at and near the surface than lower down, the vaporization of.the liquid at the surface being utilized for regulating the heating, and .the vapour pressure allowed ,being determined by means .of an adjustable-spring.

8. A method of operating internal combustion engines with liquid fuel injection, particularly Diesel engines, comprising supplying liquid fuel to the engine under pressure, heating the liquidfuel while on its way to the cylinder under pressure to a regulated temperature intermediate its vaporization temperature under pressure and its vaporization temperature at the lower pressure within the cylinder, the preheating of the liquid fuel being effected in successive stages, and in.

each stage to a temperature a few degrees below the saturated vapour temperature corresponding to the pressure prevailing in the said stage, and

the pressure in the last stage being lower than the injection pressure. 1

. 9. A method of operating internal combustion engines with' liquid fuel injection, particularly Diesel engines, comprising supplying liquid fuel tothe engine under pressure, heating the liquid 7 fuel While on its way to'the cylinder under presi sure, regulating the heating of the fuel up to the the fuel into the engine cylinder.

10. A method of operating internal combustion engines with liquid fuel injection particularly Diesel engines, comprising supplying liquid fuel to the engine under pressure, heating the liquid fuel 1while-on its way to the cylinder under pressure,

regulating the heating of the fuelby means of A the difference in physical properties between the vapour and the liquid to maintain the temperature thereof intermediate its vaporization temperature under pressure before injection and its vaporization temperature at the lower pressure within the cylinder tothereby maintain the fuel in the liquid state prior to its introduction into the cylinder and to provide suflicient heat in the fuel so that jvaporizationresults because of the heat contained therein when introduced into the cylinder at said-lower pressure,- and then injecting the fuel into the engine cylinder.

- 11. A method of operating internal combustion engines with liquid fuel injection, particularly Diesel engines, comprising supplying liquid fuel to the engine under pressure, heating the liquid fuel while on its way't'o the cylinder under pressure, regulating theheating of the fuel by utiliz ing the difference-in density between the vapour and liquid fuel to-. maintain the temperature thereof intermediate its vaporization tempera-- ture under pressure before injection and its vaporization temperature at the lower pressure within the cylinder to thereby maintain the fuel in'the liquid state prior to its introduction into the cylinder and to provide, 'sufficient heat in the fuel so that vaporization res ts because of the heat contained therein when introduced into the cylinder at said lower pressure, and-:then injecting the fuel-into the engine cylinder.

12. In an internal combustion engine iof the character described having a source of liquid fuel,

the combination of regulable means for heating'\;, the fuel prior to its injection into the engine to .a ,point such that the fuel will be vaporized through the reduction of'pressure and the heat contained in the liquid itself upon injection into the engine, means cooperating with said heating means for preventing the application of such, quantitiesof heat tothe fuel that it is vaporized prior.to its injection, and means for injecting the heated non-vaporized fuel into the engine.

the engine cylinder, a heating liquid chamber surrounding the fuel chamber and communicating directly therewith, and cooling means for liquid chamber.

14. In an internal combustion engine of the character described having a source of liquid fuel, the combination of regulable means for heating the fuel prior to-its injection into the engine to a point suchs/that the fuel will be vaporized through thereduction of the pressure and the heat contained in the liquid itself upon -injection into the engine,.means cooperating with said heatin means and actuated in accordance with the diffe ence in physical properties between'the vapor and liquid for preventing the application. of such quantities of heat-to the fuel that it is vaporized prior to its injection, and means for injecting the heated non: vaporized fuel intothe engine. I

15. In an internal combustion engine of the character described having a source of liquid fuel, a combination of regulable means for heating the fuel 'prior to its. injection into the engine to a: point such that the fuel will be vaporized through the reduction of the pressure and the heat contained in the liquid itself upon injection into,the engine, means responsive respectively to the densities of the liquid fuel and its vapour, and means cooperating t lith"saidv heating means and controlled by said density responsive means for preventing the application of suchquantities of heat to the fuel that it is vaporized priorto its injection, and means for injecting the heated non-vaporized fuel intothe' engine.

16. In any internal combustion engine of the character described having a source of" liquid liquid fuel, comprising a fuel chamber leading to condensing the vapour generated in the: heating i heating means for preventing the application of such quantities of heat to the fuel that it is vaporized prior'to its injection, said last mentioned means including means responsive to the vapour pressure of the fuel, and means for regulating said heating means to reduce the quantity of heat supplied to the fuel upon increase in vapour pressure thereof, and means for injecting the heated non-vaporized fuel into the engine.

1'1. In an internal combustion engine having a supply of liquid fuel, the combination of means for subjecting the fuel to pressure, means for preheating the liquid fuel to a temperature closely approaching but not exceeding its vaporization temperature corresponding to its pressure, means providing for a preliminary relaxation of pressure with vaporization of a portion of the fuel, compressor means for compressing the mixture of vapor and liquid with the production of a quantity of heat, and means for injecting the fuel into the engine cylinder with further vaporization of theliquid portion thereof.

18. In an internal combustion engine having a supply of liquid fuel, the combination of means for subjecting the fuel to pressure, regulable means; for preheating the liquid fuel to a temperature closely approaching but not exceeding its vaporization temperature corresponding to its a pressure, means providlngfor a preliminary re-