RU2651925C1 - Atomizer of valve injector for internal combustion engine and method of its assembly - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: invention can be used in internal combustion engines (ICE) fuel injection systems. Atomizer of valve jet of internal combustion engine, consisting of cylindrical body 1 of atomizer with channels 2 of fuel supply is proposed. Body has through central cylindrical hole 3, end of which is made in form of seating 4. In hole 3 of body 1 of atomizer with the possibility of axial movement rod 5 of valve, one end of which is made in form of valve 6 and the other end is rigidly connected to valve-stem guide 7, spring load with respect to the body of atomizer by means of valve spring 8. Surfaces of the valve 6 and seating 4 of valve are formed as rotation bodies about axis of valve assembly, and their generators are curves of variable radius, angle between tangents to which and axis of valve assembly varies in any range from 0° up to 90°. Method for assembling the atomizer of valve injector is also provided.

EFFECT: improving quality of spraying and accuracy of dosing of injected fuel.

3 cl, 4 dwg

Description

The invention relates to fuel supply systems of internal combustion engines (ICE), and in particular to electrically controlled nozzles for injecting fuel supplied to them under high pressure into the combustion chamber of an internal combustion engine.

In most cases, the supply and atomization of fuel in the internal combustion engine are carried out using modern, electronically controlled fuel-supply equipment of the battery type, the actuating device of which is electrically controlled nozzles, including nozzles with valve atomizers, which ensure proper atomization of the fuel (Schmid Andreas, Experimental characterization of the two phase flow of a Modern, piezo activated hollow cone injector / Andreas Schmid: diss. eth NO. 20852, the degree of Doctor of Sciences. - Zurich. - 2012 .-- 166 p.), (Beatrice, C., Migliaccio, M ., Montanaro, A., Fraioli, V. et al., "Experimental and Numerical Analysis of a High-Press ure Outwardly Opening Hollow Cone Spray Injector for Automotive Engines, "SAE Technical Paper 2017-01-0840, 2017, doi: 10.4271 / 2017-01-0840).

In connection with the tendency to increase the fuel injection pressure, the requirements for the quality of fuel atomization in the combustion chamber of the internal combustion engine increase, namely, it must be ensured: firstly, the formation of high-consumption short-term fuel injection pulses; secondly, fineness of fuel atomization; thirdly, the accuracy of dosing cyclic feed. The latter is especially important for controlling the engine idling, when a minimum fuel supply should be ensured, the same for each of the ICE cylinders.

Known nozzles with valve sprays (US Pat. RU 2439362 C2, DE 19534445 C2, US Pat. RU 2244151 C2, US Pat. RU 2191284 C2, US Pat. RU 2538146 and US Pat. RU 2540347 C2), in which the valve opens in the direction of flow of fuel in the process its injection. They use the conical shape of the valve and its seat, so the throttle section is an annular gap between the cones of the housing and the spray valve. Consumption characteristics of valve sprayers are largely determined by the value of the fuel consumption coefficient μ (Fuel systems and diesel efficiency / I.V. Atakhov, L.N. Golubkov, V.I. Trusov, etc. - M .: Mashinostroenie, 1990. - P. 91-103), which depends not only on the area of the passage section of the valve slit, but also on the rotation of the flow in it, and with relatively small valve lift values, the flow rotation factor is more pronounced. It is also known that the expansion of the fuel flow throttled in the valve slit improves the quality of fuel atomization.

However, in the known valve sprayers, the expansion of the fuel flow throttled in the valve slot is not fully used, the flow rotation in it is not used, and the possibilities of ensuring the accuracy of its manufacture are far from exhausted. Thus, in order to ensure the greatest fineness of fuel atomization and precision dosing of the cyclic feed, it is necessary to use the available reserves of atomizers of this type. Since the conical shape of the surface of the saddle and drip, characteristic of the above sprayer options, does not provide additional expansion of the fuel flow in the valve gap and its rotation in it, the shape of the surfaces of the saddle and drip should be changed.

For example, in the design of a nozzle with a valve spray RU 2191285 C2 an attempt was made to form a fuel flame specifically for each load-speed operation mode of an internal combustion engine. However, the fuel flames provided by this valve sprayer are similar to those produced by jet sprayers, which are much simpler in design but also do not achieve the required degree of atomization of the fuel to produce a homogeneous mixture.

Additional expansion of the fuel flow can be achieved in a vertical section if the surfaces of the valve and valve seats are made as bodies of revolution, the generators of which are curved lines of variable radius, tangent to which form an angle α with the axis of rotation, varying in any range (for example, from 30 ° to 75 °) ranging from 0 ° to 90 °. In this case, when the valve stem is moved toward the valve opening, the size of the valve slit changes by a different amount: in the upper part it is smaller than in the lower part, where the maximum size is the valve displacement at α = 90 °.

As a prototype of the design of the proposed sprayer closest to it is the design of the sprayer, which is equipped with a nozzle according to US Pat. RU 2540347 C2. The assembly dimensional chain, which includes an annular gap between the cone of the housing and the spray valve as the closing link, contains elements of not only the spray gun, but also nozzles, and since the manufacturing tolerance for each of them automatically enters the tolerance on the closing link, its accuracy is obtained low. However, the accuracy of the dosing of the cyclic fuel supply depends on the accuracy of the production of the bore, so much so that deviations within the tolerance lead to uneven fuel supply through the internal combustion engine cylinders and, as a result, to instability of the crankshaft rotation speed, especially at the idle speed. The idea of the invention in terms of improving the accuracy of the size of the annular gap is that in the assembly dimension chain, the annular gap between the surfaces of the valve seat and the atomizer valve itself is a constituent link, and use the other as a closing link.

Based on this, the aim of the invention is to improve the quality of atomization of fuel and the accuracy of dosing of cyclic feed using a valve atomizer by special profiling of the annular gap between the surfaces of the housing and valve of the atomizer and increase its accuracy, achieved by a combination of structural and technological methods.

In this regard, an ICE valve nozzle atomizer is proposed, consisting of a cylindrical atomizer body with fuel supply channels inside it, having a through central cylindrical hole, the end of which is made in the form of a saddle, and installed in the central hole of the atomizer body with axial movement of the valve stem inside it , one end of which is made in the form of a valve and is exposed outside the atomizer body in such a way that, together with the seat, forms a valve assembly, and the other Heff, the valve rod is fixedly connected with the valve, installed coaxially to the central hole and the spring-loaded relative to the gun body via the valve spring. The central cylindrical hole is made in the form of three steps, one of which is the largest diameter, the other is middle, and the third is the smallest diameter, and the valve seat is located on the side of the step of the smallest diameter, the valve guide is made in the form of a sleeve, and the surfaces of the valve and valve seat are made in the form of bodies of revolution around the axis of the valve assembly, and their generators are curves of variable radius, the angle between the tangents to which and the axis of the valve assembly varies in any range within t 0 ° to 90 °.

The inventive step of the proposed spray consists in the fact that the surfaces of the valve and valve seats are made in the form of bodies of revolution around the axis of the valve assembly, and their generators are curves of variable radius, the angle between the tangents to which and the axis of the valve assembly varies in any range from 0 ° to 90 °, which allows to achieve additional expansion of the fuel flow not only in the horizontal section, but also in the vertical, as well as to ensure the rotation of the fuel flow, contributing to the achievement of shallow STI atomization of fuel.

To achieve the necessary accuracy of the nominal size of the annular gap of the valve sprayers, only constructional measures are not enough. This may be facilitated by the original atomizer assembly method.

So, in order to ensure a complete fuel cycle even for a short pulse, the nominal size of the annular gap of the atomizer should be small, i.e. no more than 0.1 mm. Structurally ensuring accuracy of this size should be such that the spread between the magnitude of the cyclic feed at the same duration of the control pulse satisfies the conditions for controlling the idle speed of the engine, ensuring its stability. However, as an assembly unit, it is necessary to consider not only the sprayer, but the entire nozzle, therefore, one of the drawbacks of valve sprayers is that the assembly dimensional chain, the closing link of which is just the annular gap between the cones of the housing and the spray valve, includes a large number of links , and, as you know, the tolerance on the size of the closing link is equal to the sum of the tolerances of all the component links (Soloviev S.N. Fundamentals of ship engineering technology. - L .: Sudostroenie, 1977, p. 119), which leads to an increase admission to the annular gap. This means that in order to increase the accuracy of the size of the annular gap, it is necessary to tighten the tolerances on the component links, and this, in turn, leads to a significant increase in the cost of the structure.

To ensure the accuracy of the valve slit, expansion joints are usually introduced into the assembly dimensional chain, such as, for example, the X ₂ link in the nozzle design according to US Pat. RU 2540347. However, it is not possible to adjust the stroke of the core of the drive electromagnet integrated in the nozzle design so precisely, without being able to directly measure the adjustable throttling section. In addition, the design of a nozzle with a valve atomizer usually provides a method of fastening the valve stem inside the atomizer body, since during assembly it is inserted from the outside and, being loose in it, will be carried out by the fuel stream into the combustion chamber. To this end, the valve stem is additionally equipped with some element rigidly connected to it (in the design according to US Pat. RU 2540347, this element is a valve guide), and this fixed connection is made during assembly either by one of the pressing methods, or one of the welding methods . Obviously, the pressing of the valve guide onto the valve stem in this example is carried out until the end of the valve stem abuts against the valve guide. More complex is the assembly of the nozzle atomizer according to US Pat. RU 2191284, and also according to US Pat. RU 2244151 and others. Thus, none of the considered methods of assembly does not provide the necessary accuracy. In this regard, the technological route of assembly of the sprayer must be changed.

Known electrically controlled high-pressure nozzles for fuel injection in diesel power systems with direct fuel injection and with valves opening outward along the fuel flow during injection, which are driven by piezoelectric actuators (US Pat. RU 2439362 C2). Their device allows you to control not only the duration of injection, but also the amount of valve lift from the seat to any arbitrarily small value, since control is carried out by changing the magnitude of the magnetic flux through a packet of elements with a piezoelectric effect. With this control principle, the size of the valve gap does not depend on the length of the assembly dimensional chain, but is carried out by software and due to output electrical stages. However, to ensure the necessary highly dynamic response, their design is unreasonably complex. High requirements for the quality of materials used for the manufacture of individual elements of such fuel injectors, and for tolerances for their manufacture, lead to the high complexity of processing and control and, as a result, to the high cost of manufacturing. Therefore, such high-pressure fuel nozzles do not meet the requirements of the manufacturability of their serial production.

The method of assembly of the atomizer valve nozzle of an internal combustion engine according to US Pat. RU 2540347 (prototype) consists of the sequence of the following production operations: a valve stem is inserted into the central hole of the spray gun housing from the step of the smaller diameter hole so that the valve surface coincides with the surface of the valve seat, then a spring is put on the valve stem from the opposite side and press on the valve guide.

However, in order to increase the accuracy of dosing of the cyclic feed using a valve sprayer, it is necessary to ensure strictly regulated (precision) valve travel. This is achieved by the accuracy of the gap between the valve guide and the ledge of the spray housing in the locked position, which can be achieved by a new assembly method, characterized in that a ring insert of low-melting material is applied to the valve seat before inserting the valve stem, nominal size which is equal to the size of the annular slit of the valve assembly in the open state, then, on the opposite side of the spray gun body, the valve valve until its end comes into contact with the ledge of the atomizer body and in this position the valve stem is pressed into the valve guide until the valve surface comes into contact with the annular insert of fusible material, after which the valve assembly is heated to the melting temperature of the fusible material of the insert, melt it and blow it out with air, pumped through the openings of the fuel channel.

Instead of pressing the valve stem into the hole of the valve guide (which ensures their immobility with respect to each other), one of the welding methods can be used. Therefore, after a spring is put on the valve stem, the valve guide is put on until its end contacts the ledge of the atomizer body, and on the other hand, the valve surface of the valve stem is pressed against the ring insert of fusible material and in this position the valve stem is welded to the valve guide with one from welding methods, after which the valve assembly is heated to the melting temperature of the fusible material of the insert, melt it and blow it out with air pumped through the openings of the fuel channel but.

In FIG. 1 is a sketch of a nozzle of a valve nozzle of an internal combustion engine; in FIG. 2 is a variant of the valve assembly, with the shape of the valve surface and the valve seat in the form of curves of variable radius, the angle between the tangents to which and the axis of the valve assembly varies in the range from 30 ° to 75 °; in FIG. 3 shows a method for connecting a valve guide and a valve stem by welding; in FIG. 4 is a sketch of a valve assembly with a fusible insert.

The atomizer of the valve nozzle (Fig. 1) consists of a cylindrical housing 1 of the atomizer with fuel supply channels 2 inside it, having a through central cylindrical three-stage hole 3, the end of which is made in the form of a valve seat 4, and mounted with the possibility of axial movement inside the central hole 3 of the rod 5 valve, one end of which is made in the form of valve 6 and exposed outside the housing 1 of the atomizer so that, together with the seat 4, forms a valve assembly, and the other end of the valve stem 5 is rigidly connected to the valve guide 7, coaxially mounted in the central hole 3 of the atomizer housing 1 and spring-loaded relative to it by means of the valve spring 8. The clearance h between the end face of the spring-loaded valve guide 7 and the step of the largest diameter hole is equal to the valve stroke.

The surfaces of the valve 6 and the seat 4 are made in the form of curves of variable radius, the angle between the tangents to which and the axis of the valve assembly varies in any range from 0 ° to 90 ° (Fig. 2). The mating surfaces of the valve assembly are equidistant.

The immobility of the connection (Fig. 3) of the valve guide 7 and the valve stem 5 relative to each other is provided by one of the welding methods using the weld 9.

This sprayer is intended for use in shock-type nozzles, where it works as follows.

When a control pulse from the electronic control unit exerts an influence on the nozzle electromagnet, its core acts on the valve stem 5 through the hammer (not shown), which moves down by the gap value h until the valve guide 7 stops against the ledge of the atomizer body 1. Fuel under pressure enters from the accumulator through the fuel supply channels 2 into the central three-stage hole 3 and through the atomizer valve assembly formed by valve 6 and seat 4, is sprayed into the combustion chamber of the internal combustion engine.

Fuel injection stops when the control pulse disappears upon the command of the electronic control unit to the nozzle electromagnet, and the electromagnetic force holding the core of the electromagnet disappears, so it returns to its original position with the hammer. The valve guide 7 together with the valve stem 5 under the action of the force caused by the fuel pressure also returns to its original position, and the valve assembly closes.

A new method of assembly is as follows (Fig. 1).

A valve stem 5 is inserted into the atomizer housing 1 so that the surface of the valve 6 coincides with the surface of the valve seat 4, then a spring 8 is put on the valve stem 5 on the central hole 3, and an annular insert 10 is applied to the saddle 4 (Fig. 4 ) from a fusible material, the nominal size of which is equal to the size X of the annular slit of the valve assembly in working condition, then the valve guide 7 is inserted into the central hole 3 until its end comes into contact with the ledge of the atomizer body 1 and in such a way dix rod 5 is pressed in the valve guide of the valve 7 to its valve contact surface with the annular insert of fusible material 10, after which the valve assembly is heated to the melting temperature fusible material paste, it is melted and blown air being blown through the fuel inlet channels 2.

Instead of pressing the valve stem 5 into the valve guide 7 (as an option), it is placed in the central hole 3 and pressed against the ledge of the atomizer body 1, and in this position, from the opposite side of the housing 1, the valve stem 5 is pushed into the hole of the valve guide 7 until its valve surface comes into contact with an annular insert 10 of fusible material, and the valve guide 7 is welded to the valve stem 5.

The present invention is relevant, because its implementation will improve the atomization of fuel in the combustion chamber of the internal combustion engine, which will positively affect the combustion process and will increase its fuel efficiency and reduce harmful emissions. Valve nozzles are more technologically advanced than multi-nozzle ones, and controlling a valve that opens in the direction of travel of the fuel is simpler than a valve that opens toward the movement of fuel.

For the manufacture of such atomizers, equipment of the same accuracy class can be used as for atomizers commercially available for modern fuel supply equipment.

Claims (3)

1. The atomizer valve nozzle of an internal combustion engine, consisting of a cylindrical body of the atomizer with fuel supply channels inside it, having a through central cylindrical hole, the end of which is made in the form of a saddle, and installed in the central hole of the atomizer body with the possibility of axial movement of the valve stem inside it, one end of which is made in the form of a valve and is exposed outside the atomizer body in such a way that, together with the saddle, forms a valve assembly, and the other the end of the valve stem is rigidly connected to a valve guide coaxially mounted in the central hole and spring-loaded relative to the atomizer body by means of a valve spring, characterized in that the central cylindrical hole is made in the form of three steps, one of which is the largest diameter, the other is the middle and the third is the smallest diameter and the valve seat is located on the step side of the smallest diameter, the valve guide is made in the form of a sleeve, and the surfaces of the valve and valve seat are made in the form bodies of revolution around the axis of the valve assembly, and their generators are curves of variable radius, the angle between the tangents to which and the axis of the valve assembly varies in any range from 0 ° to 90 °. 2. A method of assembling a spray nozzle for a valve nozzle of an internal combustion engine, consisting of the following operations: a valve stem is inserted into the central hole of the spray gun housing from the side of the step of the smaller diameter so that the surface of the valve coincides with the surface of the valve seat, then from the opposite side to the central a spring is put on the valve stem and a valve guide is pressed in, characterized in that it is sprayed onto the valve seat in the housing Before inserting the valve stem, an annular insert of fusible material is applied, the nominal size of which is equal to the size of the annular slit of the valve assembly in the open state, then on the opposite side of the atomizer body, the valve guide is inserted into the step of the central hole of the largest diameter until its end contacts the ledge the sprayer body and in this position, press the valve stem into the valve guide until its valve surface comes into contact with the annular insert from fusible material, after which the valve assembly is heated to the melting temperature of the fusible material of the insert, it is melted and blown out by air pumped through the openings of the fuel channel. 3. The method of assembly of the atomizer of the valve nozzle of the internal combustion engine according to claim 2, characterized in that after the valve spring is put on the valve stem, the valve guide is put on until its end contacts the shoulder of the atomizer body, and on the other hand the valve surface of the rod the valve is pressed to the annular insert of fusible material and in this position, the valve stem is welded to the valve guide using one of the welding methods, after which the valve assembly is heated to the melting temperature easily inserting fusible material, it is melted and blown air being blown through the fuel passage openings.

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