RU2242622C2 - Welded manifold of internal combustion engine - Google Patents

Abstract

FIELD: mechanical engineering; internal combustion engines.

SUBSTANCE: invention can be used in exhaust systems of internal combustion engines. Proposed welded exhaust manifold contains connecting flanges connected by several pipes of different length made up of separate branch pipes. Branch pipes of longer pipes are assembled of three telescopic lengths of pipes welded by end faces in tandem relative to each other to form zigzag. Linear expansion coefficient of material of intermediate length of pipe of telescopic connection is less than linear expansion coefficient of material of conjugated lengths of pipes of telescopic connection of corresponding branch pipe.

EFFECT: reduced hydraulic resistances in exhaust duct of engine, improved sealing of manifold-to-engine frame butt joint.

2 cl, 2 dwg

Description

The invention relates to mechanical engineering, in particular engine manufacturing and is related to the design of the elements of the exhaust system of the exhaust gas of an internal combustion engine (hereinafter ICE).

A known exhaust manifold of the internal combustion engine of a VAZ-2108 car (Vershigora V.A. et al. VAZ-2108 car. M .: DOSAAF USSR, 1986, p.27), which is a massive cast part made of cast iron. The exhaust manifold has attachment flanges for fastening, on the one hand, to the cylinder head of the engine, and on the other hand, to the exhaust pipe exhaust pipe. During the operation of the internal combustion engine, the collector is exposed to significant temperature effects from the exhaust valves of the internal combustion engine.

Similar designs of exhaust manifolds are described in US Pat. Nos. 5,347,810, IPC 5 F 01 N 7/10, 1994, 5069036, IPC 5 F 01 N 7/10, 1991, EPO (EP) 0049459, F 02 F 11/00, 1982.

A common drawback of the devices described above is their significant metal consumption and heat capacity, i.e. during the operation of the internal combustion engine, their massive cast-iron structure takes a significant amount of heat, which is necessary if a catalytic converter is provided in the exhaust system, which is caused by modern high requirements for the maximum permissible content of internal combustion engine exhaust gases (products of incomplete combustion of the working mixture )

Known technical solutions to reduce the heat capacity of the described reservoir designs (see, for example, Japanese application No. 63-215809, MKI F 01 N 7/10, 1988). Here, in the inner main part of the collector, with the formation of a gap relative to the inner walls of the collector, a thin-walled pipe is installed. But this technique greatly complicates the design of the collector.

Welded exhaust manifolds of lightweight construction, stamped from a thin heat-resistant metal sheet, with welded connecting flanges (PCT (WO) 90/06207, MKI5 V 23 K 31/02, are widely used in modern ICE designs, in the exhaust route of which catalytic converters are provided, 1990, USA No. 4656830, MKI4 F 01 N 3/18, 1987, France No. 2644207, MKI5 F 01 N 7/10, 1990, Germany No. 4200611, MKI5 F 01 N 7/10, 1993, EPO (EP) 0623739, MKI5 F 01 N 7/10, 1994).

The use of such welded exhaust manifolds in combination with various types of catalytic converters allows the implementation of stringent international toxicity requirements of Euro-3 and Euro-4. The technical difficulties that arise in the manufacture of the described collectors are, first of all, in the fact that it is necessary to observe the optimal, from the point of view of hydraulic resistances, geometric parameters - bending radii of individual pipes, lengths of individual pipes, their specific location in the cramped space of the engine compartment and a number of other parameters. Therefore, as a rule, each of the individual pipes of the collector is made by welding the individual components of the pipe elements. Moreover, the connectors can be either longitudinal (Japanese application No. 3-63644, MKI5 F 01 N 7/10, 1991) (stamped from two halves), or transverse (Germany No. 3720714, MKI4 F 01 N 7/14, 1989) (when each of the pipes is welded from separate pre-shaped pipes). Or in the completed design of the collector, both of the above techniques are applied simultaneously (France No. 2727466, IPC6 F 01 N 7/10, 1996).

As a prototype, a welded exhaust manifold for the internal combustion engine of cars was selected (utility model of Russia No. 14974, MPK7 F 01 N 7/10, publ. In BIPM No. 25, dated 10.09.2000), which contains at least two flow pipes consisting of for example, from nozzles fastened together by welding, the upper ends of which are connected to the intake openings of the internal combustion engine through the holes of at least one flange, and the lower ends of the pipes, at least two, are connected to the collector elements, the lower ends of which are fixed to the lower outlet flange and through his TIFA communicated with the exhaust gas treatment system pipes, said pipes both flow tubes are made of heat resistant sheet material. The collector elements are made in the form of funnels, while the upper ends of both flow tubes are mounted on a solid inlet flange. The lower outlet flange is made of sheet material, mainly of heat-resistant steel, with flanging along its edges and holes and welded beads at the locations of the mounting holes. All nozzles are made of one material.

The disadvantages of the considered welded exhaust manifold, as shown by the practice of its operation on individual models of VAZ automobiles, are, first of all, the fact that, subject to significant temperature changes, the rigid design of the manifold, having different lengths of pipes, the material of which has the same linear expansion coefficient, accumulates significant residual deformations, which ultimately leads to a violation of the tightness in the junction of the collector with the engine housing. In addition, the manufacture of individual manifold pipes from individual nozzles, which in turn are welded from several short or straight pipe sections, followed by welding leads to non-optimal geometric parameters of the collector as a whole, which increases the hydraulic resistance in the exhaust path of the internal combustion engine, reduces its power and torque. In particular, in the prototype, the nozzle of the first cylinder is welded from two curved pipe sections, the nozzles of the second and third cylinders are welded from two pipe sections, and the nozzle of the fourth cylinder is welded from four pipe sections, two of which are straight and two are curved, bent along the radius .

To eliminate this undesirable phenomenon in a known exhaust manifold, it is proposed to provide a flow pipe with smaller linear dimensions with a temperature compensator. In addition, it is proposed that large linear dimensions of the flow pipe nozzles be made integral and their geometric parameters optimized, especially in the bend zone of each individual pipe, in order to achieve minimal water losses in the exhaust system tract.

The essence of the invention lies in the fact that in a welded exhaust manifold containing connecting flanges, at least two flow pipes, one of which (longer) is formed by converging at the outlet pipes of the first and fourth ICE cylinders, and the other (which is shorter than the first) is formed by converging at the outlet with nozzles of the second and third cylinders, the upper ends of which are connected to the intake openings of the internal combustion engine through the openings of at least one flange, and the lower ends of the pipes are fixed to the lower outlet flange and through the holes are in communication with the exhaust pipelines of the gas purification system, the pipes being made of heat-resistant sheet material, the pipes of shorter pipes made of three telescopically mounted pipe segments that are welded at the ends in series with each other, forming a zigzag, while the material from of which an intermediate pipe segment of a telescopic connection is made, has a linear expansion coefficient of a value smaller than the corresponding coefficient of the material mating with it from pipe cutting telescopic connection of the corresponding pipe.

Separate nozzles of longer pipes are made of an integral segment of a thin-walled heat-resistant pipe, while their bending radii are 1.8-2.2 diameters of the corresponding pipe in the place of its bending.

The invention is illustrated in figures 1 and 2.

The welded exhaust manifold contains at least two flow pipes 1 and 2, one of which is formed by converging outlet pipes 3 and 4, respectively, of the first and fourth internal combustion engine cylinders, and the other is formed by converging outlet pipes 5 and 6, respectively, of the second and third cylinders, the upper ends which are connected to the inlet of the internal combustion engine through the openings of at least one flange 7, and the lower ends of the pipes are fixed to the lower outlet flange 8 and are connected through the openings with the exhaust pipes of the cleaning system call, with the tube 1 and 2 are made of heat resistant sheet material. The nozzles 5 and 6 of the shorter pipes 2 are made of prefabricated three telescopically mounted pipe sections 9, 10 and 11, which are welded at the ends 12 in series with each other, forming a zigzag, the material of which the intermediate section of the pipe 10 of the telescopic connection is made has a coefficient of linear expansion smaller than the corresponding material coefficient of the pipe sections 9 and 11 of the telescopic connection of the corresponding pipe 5 or 6 mating with it.

Separate nozzles 3 and 4 of the longer pipes 1 are made of an integral segment of a thin-walled heat-resistant pipe, while their bending radii are 1.8-2.2 diameters of the corresponding pipe 3 and 4 in the place of its bending.

The diagram shown in figure 2 clearly illustrates the processes that occur when the design of the collector is heated. The welded collector is a structure with statically indeterminate deformations in the rods (pipes 3 ... 6) when the temperature of the structure changes. A diagram of the necessary extensions of the rods when heating the entire structure, provided that no force deformations occur, is shown in FIG. 2. The dashed lines show the rods in the position that they occupy after heating. Rod 1 received an increment Δ L ₁ , rod 2 received an increment Δ L ₂ , while the connection point of the rods D moved to position D ₁ .

The ratio of the increments of the rods, based on geometric considerations (similarity triangle ASD and triangle increments of rods D ₁ KD) should be equal

If the linear expansion coefficients (CLC) of the materials of the rods 1 and 2 are equal, given the fact that the temperature deformations of the rods are proportional to their lengths, this ratio cannot be ensured. In order for the strains to be compatible, it is necessary to determine the ratio between the CRC of rods 1 and 2 from dependence (1). Assuming that

Δ L ₁ = α ₁ · L ₁ · Δ t,

Δ L ₂ = α ₂ · L ₂ · Δ t,

we get

From dependence (2) it follows that for the design of the collector with an angle β = 60 °, provided that there are no force strains, it is necessary to select the materials of the rods 1 and 2 with linear expansion coefficients that differ by about two times.

In practice, this means that pipe 1 (Fig. 1), pipe segments 9 and 11 of pipe 2, can be made, for example, of material 12X18H9T with a CLR equal to 19.5 · 10 ^-6 1 / ° С, and the intermediate one in a telescopic connection section 10 is made of material 15X28 with a CRR equal to 11.0 · 10 ^-6 1 / ° С (Marochnik of steels and alloys / V.G. Sorokin, A.V. Volosnikova, S.A. Vyatkin, etc. M .: Engineering, 1989.640 s.).

In addition, with this design, minimal water losses are achieved in the ICE exhaust path, which leads to an increase in power and an increase in the torque of the ICE.

The proposed technical solution is industrially applicable, since it can be used industrially in the automotive industry and other areas of the national economy, workable, feasible and reproducible.

The device works in the usual way.

At the exhaust gas exhaust cycle from the engine cylinders, when the exhaust valve is open, hot exhaust gases are displaced into the exhaust manifold, then they enter the catalytic converter, leak through its active substance and are sufficiently cleaned of harmful substances into the muffler (silencers, if in the tract there are several of them), while losing some of the sound energy, after which they are released into the atmosphere.

Using the claimed technical solution allows you to create an inexpensive and compact design of an efficient, reliable exhaust manifold, increase the competitiveness of domestic cars by complying with their environmental safety to international standards, reduce air pollution in settlements with toxic exhaust components of vehicles, the power unit of which is based on ICE.

Claims (2)

1. A welded manifold of an internal combustion engine containing connecting flanges connected by several pipes of various lengths made up of separate pipes, characterized in that the pipes of shorter pipes are made of prefabricated pipes of three telescopically mounted pipe sections that are welded at the ends in series with each other, thus forming a zigzag, while the material from which the intermediate section of the telescopic pipe is made has a linear expansion coefficient of less than minutes, than the corresponding coefficient of the material of mating with them pipe sections telescoping connection of the corresponding pipe. 2. The welded manifold according to claim 1, characterized in that the individual nozzles of the longer pipes are made of an integral segment of a thin-walled heat-resistant pipe, while their bending radii are 1.8 ... 2.2 diameters of the corresponding pipe in the place of its bending.

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