US2067461A

US2067461A - Compression ignition engine

Info

Publication number: US2067461A
Application number: US102379A
Authority: US
Inventors: Robert P Ramsey
Original assignee: Nat Supply Co
Current assignee: National Supply Co
Priority date: 1936-09-24
Filing date: 1936-09-24
Publication date: 1937-01-12
Anticipated expiration: 1954-01-12

Description

Jan. 12, 1937. R, R RAMSEY 2,067,461

COMPRESSION IGNITION ENGINE Filed Sept. 24, 1956 2 Sheets-Sheet 1 l/ I I 1 4 10 K14 I 7 F. F 1 3mm 1 9 1 R. P. RAMSEY COMPRESSION IGNITIQN ENGINE Jan. 12, 1937.

Filed Sept. 24, 1936 4 2 Sheets-Sheet 2 Patented Jean, 1931.

UNITED STATES PATENT OFFICE 2.061.461 compssron rcnrrron ENGINE Robert P. Ramsey, Philadelphia, Pa, assignor to. The National Supply Co. of Delaware, Toledo, Ohio, a corporation of Delaware Application September 24, 1936, Serial No. 102,379

2 Claims. (a 123-32) vision ofmeans to accomplish the most advantageous combustion of the fuel injected into a compression ignition engine.

Another object of the invention is the provision of a means for controlling the combustion of fuel, portions of which assume difierent physi-.

cal states upon injection, which consists in providing for each portion air in the conditions most desirable for the advantageous burning of that portion.

Another object of the invention is the provision of an apparatus, wherein main and auxiliary combustion chambers are provided and so. disposed with .relation to a fuel injection nozzle that portions of the fuel spray in different physical conditions are fed to the two chambers, and the air in the respective chambers is in the proper condition of turbulence required to burn advantageously the part of the fuel in that chamber.

More specifically an object of the invention is to inject a, fuel stream through a chamber containing relatively quiescent air, into which the 7 highly atomized envelope of the stream distributes itself, while the dense core of the stream passes into a chamber containing rapidly swirling air with which it is mixed. I

Other objects and advantages of the invention will become apparent as the description proceeds, reference being had to the accompanying drawings, in which- Figure 1 is a fragmentary sectional view with parts in full, of an engine embodying the present invention, the section being taken on line l-l of Fig. 2; Fig. 2 is a section on line 2-2 of. Fig. 1; Fig. 3 is a somewhat diagrammatic sectional view of the combustion chambers showing a longitudinal section through a typical fuel nozzle and spray; Fig. e is an enlarged view of a nozzle tip; Fig. 5 is a cross-sectional view through a typical fuel spray, and Fig. 6 isa typical indicator diagram tak n dinin operation of an engine constructed in accordance with the present invention. Referring to the drawing the present invention is shown in connection withan engine having a cylinder t surrounded ,byjja water jacket 2 substantially its entirejworklng length. A piston 3 works in the bore of the cylinder in the usual manner.

The present invention is particularly directed to the cylinder head part of the engine, which includes a body 4 bolted to the cylinder block and spaced therefrom by suitable gaskets '5. A

fuel injection nozzle 6 is seated in one side of the head and is disposed to discharge fuel directly into a main combustion chamber I. The fuel injection nozzle is preferably of the pintle type and includes a reciprocating plunger 20 having a conical seat 2| adjacent its forward end, which is adapted to cooperate with a congruous conical surface 22 formed in the body of the nozzle. The nozzle opening 23'communicates with the interior of the nozzle and is made slightly larger than the pintle 24, which projects through the opening. The pintle is formed-with reversely

conical surfaces

25 and 25 at its tip which control to a. certain extent the angularity of the spray discharge. The plunger is backed by a spring 21, which controls the pressure required to open the nozzle, so that fuel may discharge into the cylinder head. Fuel is introduced into the nozzle through a passage 18 under a predee termined pressure and this pressure, exerted on the forward end of the plunger 20, lifts the conical valve 2| from its seat so that fuel may pass through the opening 23 around the pintle 24.

The main combustion chamber 1 is open at its bottom to the cylinder and is shaped to present a minimum of surface for the dissipation of .heat and to form a space suited to permit the outer spray envelope of the f l jetfrom the nozzle 6 to distribute itself most oroughly and mingle with the air in the chamber. To this end, the chamber is preferably made to flare from the injection nozzle so that the conical spray discharge will not impinge on the side walls of the chamber. The dimension of this main combustion chamber in the line axially of the fuel injection nozzle 6 is dictated by the consideration that the atomized portion, or spray envelope, of the injected jet of fuel penetrates the compressed gas in the chamber only a certain distance for a given injection and compression pressure, It is desirable that the spray envelope of the jet be confined within the walls of the main combustion chamber for a purpose. which will presently become apparent.

It has been-found that the discharge from a nozzle of the pintle type is divided into two parts 0 which differ widely in their physical character, istics. As shown in Figs. 3 and 4, the spray pattern shows a core C of fuel which is in substan- 'tially solid, coarsely atomized, form surrounded by an envelope 1) of highly atomized fuel partization, penetrates only arelatively small distancev into the heavy compressed atmosphere in'the cylinder head, and also, due to its fine atomization,

is adapted to burn quickly and smoothly in a quiescent volume of air. On the other hand, the substantially liquid central core C of the fuel spray will penetrate a much greater distance in the heavy atmosphere and, before it can be efllciently burned, must be broken up to be intermingled with air particles required for combustion.

While the invention has been disclosed in connection with a nozzle of the pintle type, it should be appreciated that any other nozzle which discharges a spray having similar characteristics of core and envelope may be used.

In order to burn the coarse central core 0 of the fuel stream, an auxiliary combustion chamber 9 is provided at the opposite sideof the main combustion chamber 1 to the injection nozzle. The chamber 9 is cylindrical in form and its axis is preferably parallel to the axis of the working cylinder I. The auxiliary combustion chamber 9 communicates with the main combustion chamber i through a passage l0 which is axially aligned with the fuel injection nozzle 6 and which may be belled, or slightly enlarged at its opening into the combustion chamber i to an extent such that it includes the heavy liquid part of the injected fuel spray. The opening of the passage I0 into the auxiliary combustion chamber 9 is disposed tangentially of the cylindrical wall of the latter, so that a rapid swirl of air in the auxiliary combustion chamber is set up when air is forced into the main chamber and thence into the auxiliary chamber by an upward movement of the piston 3 on the compression stroke of the engine. The swirling will continue during the injection of the heavy central core of the fuel spray into the chamber, and causes the core to be broken up and thoroughly intermingled with the air in the auxiliary chamber.

A suitable air inlet valve I5 is seated in the roof of the main combustion chamber I. Air introduced through this valve scavenges the burned gases from both combustion chambers l and 9 on the intake stroke of the piston and also serves to reduce the temperature of the valve seat and valve head, thus promoting longer life of these parts.

An exhaust valve I6 is seated in the cylinder 3 head immediately overlying the piston space.

While the engine starts rapidly from cold, it may be desirable to provide emergency means to temporarily increase the compression ratio of the engine when it becomes necessary to start under extreme conditions, as when the engine has been standing for some time in extremely cold weather. For this reason a plug valve Id is placed in the passage 40 to interrupt communication between the main and auxiliary combustion chambers during the starting period. The valve may be operated by any suitable means, manual or automatic. It will be appreciated that when this valve is closed the compression ratio of the engine is increased by the extent that the available compression space is diminished. Obviously the increase in compression causes an increase in resulting air temperature which, in turn, promotes rapidcold starting.

The operation of the present engine is such that the division of the fuel spray is made in accordance with its physical conditions. In the example shown, the finely atomized portion remains in the main chamber and the relatively solid core is shot on through the main chamber into the auxiliary chamber. This is advantageous since the physical condition of the spray determines the type of chamber which is best suited to burn the fuel. For a finely atomized body of fuel dispersed in air, quiescence is highly desirable, since the air and fuel particles are in ideal condition for combustion. On the other hand, a body of fuelwhich is in a substantially liquid condition must be mixed with air before it will burn, and requires turbulent air to break it up, mix with it, and produce the proper conditions for eflicient combustion. Also it is highly desirable that there be in each chamber sufilcient air for burning the fuel under the conditions existing in that chamber. If, for example, 70% to 75% of the fuel is finely atomized in the main chamber and a core comprising 30% or 25% of the fuel passes on into the auxiliary chamber,

the amount of air in the respective chambers should be proportioned in approximately the same ratio, although extra air for thorough combustion may be provided where the conditions of combustion require it.

In the quiescent chamber! the highly atomized part of the fuel will burn smoothly and quickly with a very slight ignition lag. The fueisensitivity of the engine is determined largely by the dimensions of the main combustion chamber 1,

since this chamber must have an axial dimension large enough so that the fuel envelope mixes with the air and no appreciable impingement of the atomized fuel occurs on thewall opposite chamber should be adjusted sufficiently to the degree of compression, shape of nozzle tip and injection pressure to prevent any substantial impingement upon the walls of the main combus tion chamber in order to best effect the objects of this invention. This same consideration determines the starting qualities of the engine,.

the air and burns to start the engine. It has been found in practice that in an engine in which the compression pressure is approximately 380 pounds, and fuelis injected from a pintle type nozzle under a pressure of 1600 pounds per square inch that a distance of nearly 3 inches is most advantageous to completely stop the spray envelope of the jet.

The dimension from the nozzle tip to the orifice of the auxiliary chamber also physically establishes a lag between the combustion of the atomized fuel in the quiescent chamber and the combustion of the liquid core, since the latter must travel entirely across the main chamber before it can enter the turbulent chamber, and since it must circulate in the turbulent chamber for a period of time before it can become suiiiciently broken up to be in condition for combustion. The liquid core can actually travel through a burning mass in the main chamber 1 and remain in a substantially liquid condition having only a smailouterlayerburnedduringitspassage. The majorpartof the corewillstillentertheauxiliarychamberasaooarsespray. Intheoperation ofthe engine,ithasbeenfoundthattheflnely atomized fuel envelope burns almost as soon as it is injected into the chamber I, and an indicator card shows a consequent moderate rate of progressive pressure rise. The central heavy core moves across the open combustion space and enters the auxiliary combustion chamber which is at such a distance from the point of injection of the fuel that the core does not burn until later in the cycle after the introduction and bm'ning of the outer spray envelope in the open chamber. The core is taken up in the rotary swirl of air in the auxiiiary'combustlon chamber and is vaporized and burned, setting up a very high pressure inside the auxiliary chamber. This pressure is choked by the passage 2| so that it cannot act directly on the piston, but rather is throttled by the passage 2|, into the open chamber to act on the piston head as it recedes on the pressure stroke of the engine. The dimension of the main combustion chamber between the fuel injection nozzle and the orifice of the passage 2| is so great that as the gases issue from the chamber 8 they will not impinge on and burn the tip of the 4 nozzle.

cationthereof; it will be understood that variations may be made while retaining essential features of this invention.

a As indicated, one of the important features is the provision of a relatively quiescent body of air into which the fuel jet is directed and into which all of the fuel that can be suiiiciently atomized is distributed, so that full advantage is taken of the atomization effected by the injection,

while the relatively solid core of the fuel iet moves on into a turbulent mass of air that eifects its atomization It is preferable that these two bodiesof airshallbeinaboutthe sameproportion to each other as are the two portions of fuel that enter the respective bodies of air.

Other changes within the scope of the appended claims may be made without departing from the I invention.

Having thus described my invention, what I I claim as new, and desire to secure by United States Letters Patent, is:

1. In an internal combustion engine having a 10 cylinder and a piston therein, means providing a main .combustion chamber and an auxiliary combustion chamber communicating with the main chamber, means to inject a jetof fuel across said main chamber toward said auxiliary lo chamber, said iet consisting of a spreading, highly atomized envelope and a coarsely atomized core, said main chamber containing relatively 1 quiescent air and arranged to receive and permit the normal spreading of said highly atomized 20 portion of the fuel within its quiescent air, and said auxiliary combustion chmnber arranged to receive said core, the communication between said main chamber and said auxiliary chamber being suchas to produce a swirl of air in said auxiliary chamber, the volumetric ratio of the main combustion chamber to the auxiliary combustion chamber being substantially equal to the ratio between the parts of the fuel received in the respective chambers.

2. In an internal combustion engine. a cylinder head adapted to overlie a cylinder in which a piston operates and having main and auxiliary combastion chambers, means to inject a jet of fuel across said main chamber toward said auxiliary chamber, said iet consisting of a spreading, highly atomized portion and a coarsely atomized core, said main combustion chamber containing relatively quiescent air and arranged to receive and permit the normal spreading of said highly atomized portion of the fuel within its quiescent air and proportioned to contain that portion of the air charge used in burning said highly atomized portion, and said auxiliary combustion chamber arranged to-receive said core and proportioned to contain that portion of the air charge used in burning said core, and means to produce a swirl of air in said auxiliary combustion chamber.

ROBERT P. RAMSEY. 5o