US2356627A - Interruption injection pump - Google Patents

Description

Aug. 22, 1944. N. N. SKAREDOFF I INTERRUP'IION INJECTION PUMP Original Filed June 27, 1940 or EXPANSION a COMPRESSION POSITION OF PISTON POSITION OF PISTON I N VEN TOR.

Patented Aug. 22, 1944 i Original application June 27, 1940, Serial No." and this appllcation'November I 125, 1942, Serial No.: 466,848 4 Claims. (o1. 103 -41 I:

on United 342,638. Divided TillS,'iS a divisional application States patent application, Serial No. 342,638,.filed H i June 27.119510, under the. title-of Interruption injection pump and method to apply thesame.

This, invention relatesto a new method and new devices for elimination in toto or in part of c the so-called detonation in internal combustion engines operating on a two or-four-st'roke Diesel cycle, and. on the'Ottoj cycle using. fuel-injection pumps. 9 i

Thisinvention also is' designed-to improve the controlcof the combustion of -trial inside of a cylinder of an intern al combustion engine.

For theconvenience'ofthe description; this specification will refer to .a' single' cycle occurring duringthe operationoL-the engine. The word injection will indicate the individual injection occurring during the said cycle; The amount-of" quantity injected during-each cycle' will be re ferred to as the total his] charge or charge.-'-

ew York, N. Y., assignoroi" v, one -halfto George A Rubiss ow, New, York UNITED STATES "PATENT? This invention refers to an "interrupted inje'cthe. working cylinder. I

In the drawing, wherei-nli-ke reference char-= views, Figurel is a diagrammatical view of themessure variation in the cylinder during compression and powerstroke. v Figure 2 is a diagrammatical representation'of 1 the fuel pressure; during injection usingnormai injection cycle. 7 v

Figure 3 is a diagrammatical representation of I J fuel pressure duri-nginlection using interrupted 1 injectioncyclaw V l H V Figure 4 is a itudinalcross sectional'view' The total fuel charge, according to this invention, is to be divideddnto' two parts -the initial I injection and the"main:injeotion"; the initial injection beinga fraction of the totalfuel charge;-

comprising-the "remainder of the: fuel I and the main injection or the remainder of injection charge. i The interval :of time between the termination of the initialinjection and the beginning of the main injection, willbe referred to in this specification as the-interruption of the injection, or-the injection interruption."

In'engines'operatingon a compression fuel injection self-ignitionDiesel cycle, also called Diesel petrol) injection self-ignition the ballistic exhaust of burned gases known under Kadenacy system as more fully described in U. S. A. Patents, Nos. 2,147,200;"2,281,585; 2,134.920; 2.102.559; the injection is preferably to be divided intotwo parts, comprising a small initial injection followed by an interruption, after type cycle, or on a compression fuel (or two cycle using a the HQ (interrupted injection'cycl'e), and the-'- acters refer to like parts throughout these'veral' of an injection pump'piston withparts broken- FieureS is across-sectionalview-'5 5' of IFigure 4. I 1 I Figures-6,7 and 8arecross-sectional-views with parts broken, out showing various positions of:

valve'of the'pum'pr the groove on the rotary Figure -1diagrammatically-'represents -one of the main points of this inventiomwherein the during part of one cycle is demonstrated. ''The sequence of eventssinslde the'workingcylinder .curve AC represents an air cycleof an engine with the. top dead center of the piston marked .TDC... The curve IIG represents-the pressure;

variation inside of the working cylinder during curve of the normal injection cycle, hereinafter designated as NIC represents the variation pressure inside of the working cylinder operating on v a normal injection cycle;

which interruption the main fuel charge is in- 1 jected. Forengines operatingon a four or twov stroke. spark-ignition cycle, the injection of the fuel charge may also be dividedinto an initial charge followed by the interruption, whereafter the main charge may be injected.

The initial charge may be equal to, smaller,

or larger than the main injection. The period t of interruption may be timed in accordance with the kind' and/or amount of fuel employed, .One or more interruptions may be used, dividing the fuel charge accordingly into corresponding fractions. This applies to Diesel engines as well as to Otto cycle engine's. J

In a normal injection cycle, theinjection begins at a point marked BNI (beginning of'normal injection), and steadily continues until the point I ENI (end of normal injectionl'is'reached. Due

.to the lag ofignition, the combustion startsto occur onlyat point BIC (beginning of internal ll combustion) able portion'of fuel has already entered the com- During that interval, a considerbustion space, and when the ignition occurs, the

entire quantity of the fuel already present in the I engine to knock or detonate.

combustion space, starts to burn at once atan' uncontrollable".- rate of speech thus producing an excessively rapid pressure rise which causes the occurs near the top dead centerposition of the piston, in which region it can move only very slowly, the magnitude of pressure-attained is also I Inasmuch as i this 1 considerably in excess of what the engine was originally designed to produce. When the piston begins to move on its expansion stroke, the injection is practically completed, and the pressure drops rapidly.

When interrupted injection cycle (IIC) 'is applied, instead of normal injection cycle (NIC), the fuel injection starts at a point BII (beginning of interruption injection), and continues until the entire initial amount of fuel is injected, and stops at a point marked EII. The piston continues on its compression stroke and when the period of the lag of ignition has elapsed, this initial quantity of fuel begins to burn at a point marked BE on the diagram. As this point, the main, injection commences substantially at a point marked BMI and continues until the total amount of fuel required is injected.

It is to be noted that one of the main aspects of this invention isthe providing of the said interruption, i. the interval during which theinitial fuel chargebeginsto, burn and'produces an open flame, into which the remainder of the fuel charge is then injected.

It is also to be noted that such an interruption can be chosen in accordance with the characteristics of the engine; and the fuel used. Due to the fact that the main fuel charge, according to this invention, is injected into the open flame, the time required to ignite (lag of ignition) is reduced to such an extent, that no appreciable quantity of fuel can accumulate in the combus-' =tigii-rspace without being burned as fast as it The rateiof injection can be easily controlled by injection mechanism to inject only so much fuel into the combustion space as is necessary to maintain a certain pressure behind the receding piston during the expansion stroke. In this way. all undue stresses on an engine are eliminated,

and a-useful even working mechanism with smooth torque is obtained.

Since the pressure rise inside of the combustion spaceis, very slow and limited in magnitude, no detonation can be produced. The injection is' terminated at'a point EII after which the con- --ventional expansion follows.

The quantities of fuel injected are represented by the shaded areas, as follows: KKINNI represents the amount of fuel injected 50 showing the amount of fuel delivered to the cylinder, and similarly represented by KKiNNi shown in Figure 1.

Figure 3 diagrammatically shows the IIC with shaded area 5| representin the initial injection similar to KK1LL1 as shown in Figure 1, and area 53 represents the main injection similar to MMIOOI, shown in Figure 1. The interruption is represented by interval 52 between the areas 5| and 53.

Lines 54, 55 and 58 on Figures 2 and 3, represent diagrammatically the rise and fall of fuel pressure in the compression chamber of the pump before discharge pressure is reached, and after delivery valve is closed.

It is to be noted that Figures 1, 2 and 3 are diagrammatical views, and do not limit the relation between the quantities of fuel injected initially, and the timing employed for the termination of such initial injection and the interval of the main injection, and also do not limit the relation between the time of the injection and the position of the piston at which the injection occurs. By way of example:

(1) The initial quantity, instead of being smaller than the main injection, as shown in Figures 1 and 3, can be equal to, larger or smaller than the main injection.

(2) The relations between the three time-intervals necessary for (l) the initial injection, (2) the interruption, and (3) the main injection, are not limited by the ratio shown diagrammatically in Figures 1 and 3, and can be varied according to the type of engine and fuel employed,

Presuming, for instance, that the magnitude of the interruption interval is governed by the speed of the engine and the ignition characteristics of fuel used, then the interruption interval should be so approximately equal to, or slightly smaller than the ignition lag of the fuel used. This, however, 'does not limit the invention to any other arrangements.

Another example of arrangement of the said three timeintervals, may, for instance, be as follows:

" For a Diesel engine having a total injection period of about 20 degrees, and operating on a fuel with ignition lag amounting to 10 degrees of crankshaft rotation at operating-speed, the initial injection will start about 14 degrees before top dead center TDC and then continue until about 10 degrees before TDC. It will'then be interrupted for' about 9 or 10 degrees with the main injection commencing about 1 degree before TDC and continued until the full amount of fuel is delivered into the cylinder, depending upon the load of the engine. This is given by way of ex "ample. only, and does not limit the invention thereto.

The timing at which the initial and main in- ,jections are designed to occur is also not limited Ito that shown on Figures 1 and 3 and can be varied to produce the best results in accordance 'j with the type of engineand fuel employed.

= This new-method is not limited to a single in- -terruption as shown in Figures 1 to '7 inclusive.

More than one interruption during a single cycle can be used. If several interruptions are used, the

'sifirst intervalmaxflfor instance, be longer than the i s'econdJonef the-first initial charge equal to, greater or smaller than thesecond charge; and the remaining fuel charge equal to. greater or smaller than the initial charge.

The open flame created by the initial interruption injection reduces the lag of ignition of the main fuel charge when it begins to arrive in the combustion space, to such adegree that no appreciable amount of fuel can accumulate in the combustion space without being ignited. The fuel is burned as fast as it enters the combustion space, giving accurate control of the pressure inside the cylinder, and thereby offering a smooth and efficient operation of the engine.

One of the advantages of the interruption in- .jection consists in that it offers the possibility of using a cheap fuel of a low cetane number in high-speed engines without detonation or other harmful effects taking place. By way of example: a modern high-speed Diesel engine will not satisfactorily operate on a fuel having a cetane number below 60. The interrupted injection properly designed for fuel with a cetane number of around 20, for instance, will operate with equal efliciency and no detonation, as if a high-grade fuel were being used, a fuel, for instance, with a cetane number around 80. It must be pointed out that if a high-grade fuel is employed such as cetane number 80, the interrupted injection may not showany considerable improvement of performance, inasmuch as it is designed preferably to permit the operation of the engine on a low-grade fuel.

A practical realization of this invention is 11- lustrated in Figures 4, 5, 6, 7 and 8, representing schematically a rotary-valve type pump such as known, for instance, under the trade-mark X- Cell-O the X-Cell-O pump, converted to produce the interrupted injection.

For this purpose a groove 14 is provided parallel or at an angle to the leading edge 15 in the raised portion or land of the rotary valve 16, as shown in Figure 4. It is to be noted that groove 14 divides the land of the rotary valve into the sections Ti and 18, whereby when section 11 of the rotating valve 16 covers the suction port 19 of the given piston P, the fuel is prevented from flowing back to the suction chamber 80 and is displaced to the injector via, the spring loaded discharge valve 83,'by the advancing piston P in the cylinder 8 I.

As soon as the groove" begins to register with the suction port 19 an open passage is established between the pressure chamber 82 and the supply chamber 80 by means of suction port 19 and groove 14. During the time that groove 14 is in register with the port 19, the fuel is displaced back into the supply chamber 80, i. e. the interruption in the delivery of fuel is produced as shown by Figure 7. Thereafter, as shown on Figure 8, with the rotary valve continuing to rotate, section 18 of the land covers the suction port 19, the fuel in the pressure chamber 82 is again forced to the injector, thus beginning the main injection.

Having now particularly described and ascertained the nature of the said invention and the manner in which it is to be used, I declare that what I claim is:

1. A fuel injection pump for internal combustion engine comprising a number of pistons each reciprocating in its respective cylinder provided therefor, a plurality of spring-loaded check valves, said valves provided to control each said cylinder, port provided in each said cylinder to control the inlet of the fuel, at least one rotary valve having a cylindrical body with at least two lands, said rotary valve being located in the fuel supply chamber and controlling the inlet of the said fuel through each said port, each said land being separated from the other by a groove open on the side leading to the said fuel supply chamber, each said groove registering each said port one at a time and for a predetermined length of time, thereby establishing an interrupted fuel injection controlled by the size and shape of each said land and each said groove.

2. A fuel injection pump for internal combustion engine comprising a number of pistons each reciprocating in its respective cylinder provided therefor, a plurality of spring-loaded check valves provided to control each said cylinder, a port provided in each said cylinder to control the inlet of the fuel, at least one rotary valve having a cylindrical body with at least two lands, said rotary valve being located in the fuel supply chamber and controlling the inlet of the said fuel through each said port, each .said land being separated from the other by a groove open on the side leading to the said fuel supply chamber, said grooveregistering each said port one at a time and for a predetermined length of time, thereby establishing an interrupted fuel injection controlled by the size and shape of each said land and said groove, said groove being parallel to the edge of the leading land.

3. A fuel injection pump for internal combustion engine comprising a number of pistons each reciprocating in its respective cylinder provided therefor, a plurality of spring-loaded check valves, said valves provided to control each said cylinder, port provided in each said cylinder to control the inlet of the fuel, at least one rotary valve having a cylindrical body with at least two lands, said 'rotary valve being located in the fuel supply chamber and controlling the inlet of the said fuel through each said port, each said land being separated from the other by a groove open on the side leading to the said .fuel supply chamber, said groove registering each said port one at a time and for a predetermined length of time, thereby establishing an interrupted fuel injection controlled by the size and shape of each said land and said groove,

said groove being at an angle to the edge of the leading land.

4. A fuel injection pump comprising a body in which are provided several cylinders each having a spring-loaded reciprocating piston, at least one fuel cylinder provided with a rotating control-valve, a suitable part of said rotating control-valve being provided with at least one land divided into two parts by a slot provided in said land; said slot being open only on the end leading to the fuel chamber provided in the area of the displacement of said land, a plurality of ports interconnecting each of said cylinders with the said fuel cylinder whereby when the said land and the said slot register each of the said ports, an interrupted injection of the character described is established.

-NIKOLAI N. SKAREDOFF.

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