RU2456470C2 - Diesel injector spray nozzle for biofuel - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: diesel injector spray nozzle for biofuel includes housing (1) and needle (2). Needle (2) is located in housing (1). Annular groove (3) is made on inner surface of housing (1). There is well (6) and fuel spray holes (5) in lower part of housing (1). Inner part of holes (5) is provided with fuel flow shapers. The latter contribute to carbon formation reduction. Each shaper can be made in the form of insert (7) with screw channels, which is then continued to conical chamber (8) and to nozzle holes (5). Insert (7) is made in the form of a screw with double-threaded winding and turns of rectangular section.

EFFECT: possibility of achieving finer biofuel spray is provided.

5 cl, 4 dwg

Description

The invention relates to engine building, to nodes of diesel engine power supply systems, in particular to fuel injectors injecting oil biofuel.

A device is known for a pinless single-hole nozzle atomizer with fuel swirling (patent for utility model of the Russian Federation No. 42076 U1 dated July 22, 2004, class F02M 61/10), comprising a hollow body with a fuel feed channel and a saddle, a twisting device made in parallel located screw grooves and a twisting chamber, a locking device mounted in a hollow body, and the screw grooves extending into the twisting chamber, the nozzle sleeve is located in the saddle, interacting with the elastic element with the outer shoulder in which akruchivayuschy jet fuel element having parallel helical grooves having at the end facing the seat, the cone cooperating with the nozzle orifice located in the saddle, and the opposite end of the swirl stream of the fuel element goes into the twisting chamber defined by the internal shoulder of the sleeve dispenser.

It is also known a pin nozzle atomizer with fuel swirling (patent for the invention of the Russian Federation No. 2132480 C1 of 05.20.1997, class F02M 61/10, F02M 61/18), containing a hollow body with a fuel feed channel and a saddle, a sock with a well a twisting device made in the form of screw grooves and a twisting chamber sequentially placed under the well, and a locking needle installed in the cavity of the atomizer body to form a sub-needle chamber in communication with the fuel supply channel, moreover, the screw grooves enter the twisting chamber and s with a well, a sprayer provided with a sleeve, screw grooves formed on the outer side surface of the sock, and the sleeve is fixed to the toe to form a twisting chamber and the nozzle orifice between the inner surface of the sleeve and the outer surface of the conical shape of the sock provided with a shoulder.

The disadvantage of these devices is the impossibility of their use on diesel engines with direct fuel injection, but only on engines with separate combustion chambers, since their designs offer pinless single-pin and pin-type, which in their characteristics have worse fuel atomization compared to pinless multi-hole.

Also known is the closest in design device pinless multi-hole sprayers having a housing, a spray needle, an annular groove and spray holes (reference VG Kislov and others. "Fuel equipment of tractor and combine engines", p. 154, M .: Mechanical engineering , 1981). The disadvantages of this device when working on oil biofuels are:

- fuel is not sprayed well enough due to the weak turbulence of the jets leaving the nozzle openings;

- the duration of the fuel supply increases, the uniformity of the structure of the fuel flame decreases, the angle of the opening of the flame decreases, its range increases;

- coking of nozzle channels of the atomizer occurs;

- an increased carbon deposit is formed on the cylinder-piston group of the engine due to incomplete combustion of fuel.

The technical task of the invention is to increase the efficiency of atomization of oil biofuels by creating its twisting.

The technical result from the use of the invention lies in the possibility of achieving a finer atomization of biofuel, which increases the efficiency of diesel operation, reduces the amount of harmful emissions into the atmosphere and reduces carbon formation.

The specified technical result is achieved in that in the sprayer containing the housing, on the inner surface of which an annular groove is made, and in its lower part there are holes for spraying fuel, a needle is located in the housing, the inside of the sprayer holes is provided with fuel flow formers, each former is made in in the form of an insert with screw channels passing into a conical chamber and further into nozzle openings, the insert is made in the form of a screw with two-way winding and turns of rectangular cross section, conic The chamber has a shape that tapers towards the nozzle hole, and the wall has an angle of inclination of 60 °, chamfers are made on the outside of the nozzle openings, and the sectional areas of the nozzle holes are increased by 20%. When passing through the insert, the fuel jet spins and then passes through the conical tapering chamber, increases its angular velocity of rotation as it approaches the nozzle hole and thereby enhances the centrifugal effect, thereby improving the quality of its atomization and at the same time self-cleaning nozzle holes from deposits and soot.

Figure 1 shows the inventive spray nozzle of a diesel engine for biofuel, where 1 is a housing; 2 - a spray needle; 3 - annular groove; 4 - fuel supply channel; 5 - spray holes. An enlarged view of the holes of the sprayer is shown in figure 2, where 6 is the well of the sprayer; 7 - insert. The openings of the atomizer in section and the design of the insert are shown in Figs. 3 and 4, where 8 is a conical chamber.

The presented spray nozzle of a diesel engine for biofuel contains a housing 1, inside of which there is a needle 2 and an annular groove 3, in the lower part there are openings 5 for spraying fuel. In the inner part of the holes 5 from the side of the well of the sprayer 6 are the formers of the fuel flow (not indicated), consisting of an insert 7 and a conical chamber 8.

The insert is made in the form of a screw with two-way winding and rectangular turns, it is pressed into the inlet of the nozzle channel using the fit H7 / s6. The insert is made on standard equipment from the same material as the atomizer body, made of stainless steel 18X2H4VA.

The diameter D of the insert is twice the diameter of the nozzle hole d

D = 2 × d

since for D <2 × d we obtain a lower angular velocity of the swirling fuel flow and, therefore, lower efficiency of the atomizer. At D> 2 × d, the length of the screw channels and their angle of inclination increase, which leads to an increase in the traveling and local losses of the fuel head.

The total cross-sectional area of the screw channels on the insert S ₁ = 2 × (b × h) should be within 1 ... 1.2 of the cross-sectional area of the nozzle hole S

S ₁ = 2 × (b × h) = (1 ... 1,2) × S,

which, in turn, should be 20% larger than the cross-sectional area of the nozzle openings of the finished sprayers. When the ratio of the areas S ₁ <(1 ... 1,2) × S, an increase in the duration of injection occurs, which leads to an increase in fuel pressure and increases the specific fuel consumption for engine power. When the ratio of the areas S ₁ > (1 ... 1,2) × S, the atomization efficiency of the fuel is deteriorated by reducing the centrifugal effect during injection.

The pitch T of the screw surface is equal to the length of the insert and 1/2 of the length of the nozzle opening L

T = 1/2 × L,

since this gives the optimum length of the screw channels, their angle of inclination and the strength characteristics of the walls of the nozzle openings are observed.

The angle of inclination of the walls of the conical chamber is 60 °; a chamfer is made on the outside of the nozzle hole.

The sprayer operates as follows.

When fuel is supplied through channel 4 to the annular groove 3 and the last pressure is equal to the initial injection pressure, the locking needle 2 rises and the fuel enters the well 6 and then, through the screw channels of the insert 7, is twisted in a conical chamber 8, making a helical movement towards the nozzle openings 5. The increased cross-sectional area of the nozzle openings provides optimal throughput for more viscous biofuels.

Due to the tapering conical shape of the chamber 8, the angular velocity of rotation of the flow increases as it approaches the nozzle orifice, and upon exit from the nozzle orifice under the action of centrifugal forces, the fuel is crushed into tiny droplets forming a symmetrical torch with a wide opening angle.

The chamfer allows you to reduce the pressure loss of the fuel flow in the atomizer; at the outlet, the jet flows with the smallest reflection from the channel walls, which reduces the rarefaction zone behind the inlet part 8 of the nozzle channel and thereby eliminates the conditions conducive to cracking of the fuel and coking of the nozzle channel.

The application of the proposed design of a multi-hole atomizer for pinless nozzles gives the following result:

- improves the quality of atomization of oil biofuels, increases the uniformity of the structure of the fuel flame, increases the angle of opening of the flame;

- increases engine life by reducing the coking of the nozzle channels (self-cleaning) and reducing carbon deposits on the cylinder-piston group;

- diesel fuel consumption is reduced and the amount of harmful emissions into the environment is reduced;

- it becomes possible to qualitatively transfer the operation of a diesel engine to oil biofuel when finalizing a standard fuel injector.

Claims (5)

1. A spray nozzle of a diesel engine for biofuel, comprising a housing in which a needle is located, an annular groove is made on its inner surface, and in its lower part there is a well and holes for spraying fuel, characterized in that the inner part of the nozzle openings is provided with fuel flow formers, contributing to the reduction of carbon formation. 2. The spray nozzle of a diesel engine for biofuel according to claim 1, characterized in that each former is made in the form of an insert with screw channels, passing into a conical chamber and then into nozzle openings. 3. The atomizer of the diesel nozzle for biofuel according to claim 1, characterized in that the chamfers are made on the outer part of the holes of the atomizer. 4. The spray nozzle of the diesel engine for biofuel according to claim 2, characterized in that the conical chamber has a shape that tapers towards the nozzle hole and a wall angle of 60 °. 5. The spray nozzle of the diesel engine for biofuel according to claim 2, characterized in that the insert is made in the form of a screw with two-way winding and turns of rectangular cross section.

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