CS199257B2 - Device for fuel mixture admission and exhaust of waste gases for engines - Google Patents

Abstract

1473153 Heating I C engine charge; manifolds HONDA GIKEN KOGYO K K 29 July 1974 [30 July 1973 5 Nov 1973] 33454/74 Heading F1 Intake and exhaust apparatus for an I.C. piston engine of the type wherein the or each cylinder has a main combustion chamber and a precombustion chamber communicating with the main combustion chamber via a flame passage, the apparatus comprising intake means including a main intake chamber and at least one main intake passageway extending from the main intake chamber for delivering an air/fuel mixture to the or each main combustion chamber, the intake means also including an auxiliary intake chamber and at least one auxiliary intake passageway extending from the auxiliary intake chamber for delivering a richer air/fuel mixture to the or each pre-combustion chamber, exhaust means comprising a thin wall liner enveloped by and spaced within a thicker wall outer cover, the liner forming at least one passageway for collecting exhaust gases from the or each main combustion chamber and also forming an exhaust chamber connected to the exhaust passageway(s), the exhaust means having an opening and a heat conductive member forming a part of the intake means and in communication with said opening to transfer heat of the exhaust gases to the intake mixtures in the main and auxiliary intake chambers, the heat conductive member having a first portion adjacent the auxiliary intake chamber and a second portion adjacent the main intake chamber, the first portion having an effective heat conductive area of from “ to <SP>2</SP>/ 3 that of the second portion. The combined intake and exhaust system is shown, Fig. 2, in an engine having pre-combustion chamber 1 communicating with each main combustion chamber 2 through a restricted flow passage 6. A main carburetter assembly supplies a lean air-fuel mixture to the main combustion chambers 2 through the manifold 17 and the auxiliary carburetter supplies a rich air-fuel mixture to the auxiliary combustion chambers 1 through the manifold 16. A main fuel intake chamber 20 and an auxiliary fuel intake chamber 32 are formed adjacent a riser member 84 covering an opening in the housing 42 of the exhaust pipe manifold 15. The housing 42 encloses a liner 44 formed of thin heat resistant material such as stainless steel. The liner 44 extends from the engine head 3 to the exhaust pipe system 56 and comprises an exhaust chamber 62 having-inlets 65 from the combustion chambers and a discharge pipe 66 leading to the exhaust pipe system 56. The liner 44 is bolted to the flange 50 surrounding the opening 48 in the housing 42, and the inlets and discharge pipe are free to expand relative to the housing. A baffle 80 is provided in the exhaust chamber to divert the exhaust gases on to the underside of the main and auxiliary intake chambers 20, 32. The height of the baffle 80 is determined empirically so as to ensure the correct amount of heating of the air/ fuel mixtures and in the present embodiment the top of the baffle is 2À5 cms below the underside of the chamber 20. Ridges 86 prevent buckling of the riser member 84 and the lateral surface area of the member associated with the auxiliary intake chamber 32 should be from “ to <SP>2</SP>/ 3 of the lateral area associated with the main intake chamber 20. The vertical surface between the two lateral surfaces, in the present embodiment, is laterally spaced 3À75 to 4À0 cms from the top centre of the baffle 80. The riser surface below chamber 32 is approximately 1À5 cms below the surface under chamber 20. With a minimum thickness of 4À0 mms for the riser member 84 it is found that its temperature is in the range 160‹C-260‹C which is just suitable to vaporize the fuel. To complete combustion of the fuel the ratio of the exhaust chamber volume to the engine displacement should be within the range 0À5-0À9. The exhaust chanber volume is defined as the interior volume of the liner 44 from a vertical place tangent to the convex inner surfaces of the liner (87), Fig. 4 (not shown) to the inlet opening 89 to the exhaust pipe 66 and the plane co-incident with the under surface of the mounting plate 68. The riser 84 is made of cast aluminium and the outer cover 42 of cast iron cast about the liner 44 after it has been covered with sand a heat shield 54 prevents conduction of heat from the exhaust to the riser and also prevents direct radiation and convection between the exhaust manifold 15 and the carburetter assemblies 12, 13.

Description

In particular, the present invention is directed to such systems wherein the temperature of the exhaust gases passing therethrough is maintained at or above the reaction temperature of hydrocarbons and carbon monoxide with oxygen, and wherein heat from the exhaust system is transferred to the intake system to promote evaporation of the fuel mixture.

Internal combustion engines, comprising a secondary combustion chamber connected to the main combustion chamber by a flame whirl channel, are arranged to obtain relatively little contaminated exhaust gases. These engines use a fuel mixture whose mixing ratio is poorer than the stoichiometric mixing ratio, resulting in more oxygen in the exhaust gas. The rich fuel mixture is fed to the small secondary combustion chambers and the lean fuel mixture is fed to the larger main combustion chambers. After compression, the spark plugs arranged in each secondary combustion chamber ignite the mixture, whose mixture penetrates the flame whirling channel into the adjacent main combustion chamber. The burns are then blown from the engine. The burns contain excess oxygen which remains after burning a lean fuel mixture.

It is known that the combustion of both fuel mixtures can be improved by raising the temperature of the intake mixtures to evaporate the atomized fuel before it is ignited. Improving the quality of the fuel mixtures improves combustion of the gases in the main and secondary combustion chambers. The result is cleaner exhaust gases.

It is a known measure to introduce sufficient air into the hot exhaust gases of internal combustion engines in order to oxidize most of the hydrocarbons to water and carbon dioxide. The disadvantage of this measure is that cold make-up air lowers the temperature of the exhaust gases below an acceptable limit.

SUMMARY OF THE INVENTION The object of the present invention is to provide a device which avoids the disadvantages of the known measure by providing no additional air into the hot exhaust gas, but the desired unburned hydrocarbon reaction is ensured by keeping the exhaust gas temperature above the temperature at which the hydrocarbon reacts with excess oxygen. and ¹ for a longer period of time to convert a larger amount of hydrocarbons into carbon dioxide and water.

According to the invention, it has been solved by providing a fuel intake and exhaust gas apparatus for internal combustion engines with at least two cylinders having an auxiliary combustion chamber connected to each main combustion chamber by means of a flame whirling duct formed. suction means comprising a suction line extending from the main suction chamber for supplying the lean fuel mixture to each main combustion chamber of the engine, further auxiliary. an inlet chamber with at least one intake manifold extending from the auxiliary intake chamber, for supplying a rich fuel mixture to each engine auxiliary combustion chamber and exhaust means constituting an exhaust duct, for exhausting the flue gas from each main engine combustion chamber to the exhaust manifold, the exhaust means comprising a thin-walled inner liner surrounded by a gap with a thick-walled outer casing, the thin-walled inner liner being provided with at least one inlet exhaust pipe and an outlet pipe for evacuating exhaust gases from each main combustion chamber and forming a central exhaust chamber having an opening therethrough an inverted portion of the suction means formed by a ribbed bottom wall of the main suction chamber and a secondary suction chamber, wherein a portion of the ribbed bottom wall of the secondary suction chamber forms up to 2/3 of the effective area of the ribbed part bottom wall of the main suction chamber.

Further, according to the invention, the suction means are formed by the suction line and the exhaust means by the exhaust line.

Also, according to the invention, the thin-walled inner liner is of heat-resistant steel and the thick-walled outer liner is of cast iron.

According to another feature of the invention, the inner liner is made of a refractory sheet.

According to yet another feature of the invention, the opening of the thin-walled exhaust pipe liner and the opening of the thick-walled outer sleeve are opposite the ribbed bottom wall of the main suction chamber and the secondary suction chamber.

Yet another feature of the invention is that the thick-walled outer sleeve has a flange in which an opening is provided and the thin-walled insert is provided with an intermediate lining with an opening coaxial to the opening of the thin-walled insert.

Further, according to the invention, a baffle is provided in the central exhaust chamber towards the ribbed bottom wall of the main suction chamber and the secondary suction chamber.

Also according to the invention, the ribbed bottom wall of the main suction chamber and the secondary suction chamber has two parts forming a common bottom of the main combustion chamber and the secondary combustion chamber.

According to another feature of the invention, the distance of a portion of the ribbed lower wall of the secondary suction chamber from the intermediate liner of the thin-walled liner is less than this distance of a portion of the ribbed lower wall of the main suction chamber.

Furthermore, according to the invention, each inlet exhaust pipe and each outlet pipe of the thin-walled inner liner is housed in a thick-walled outer casing, the thin-walled liner being held against the thick-walled outer casing by fastening screws.

Finally, according to the invention, the volume of the thin-walled inner liner lies within the limits of 0.5 to 0.9 of the motor content.

The device according to the invention makes it possible to obtain an optimum mixture quality and maximum conversion of unburnt hydrocarbons into the exhaust gases. The device according to the invention also provides a clean internal combustion engine without an additional air compressor or catalytic converter and the like. The device directs a rich and clever mixture to the engine and collects exhaust gases. When the fuel mixture passes through the intake manifolds and ducts to the engine during operation, these mixtures are treated in the apparatus by the heat input between the exhaust and intake means. Heat transfer from exhaust to engine intake is used to maintain a constant temperature throughout the intake section so that both fuel - rich and lean - are heated proportionally. The proportion of heating of both fuel mixtures is maintained regardless of changes in operating conditions during engine operation. This treatment of intake fuel. mixtures. is achieved quickly by the arrangement according to the invention after a cold start of the engine, due to the low heat capacity of the system. Further, the total amount of heat transfer between the exhaust and intake means during the entire range of engine operating conditions varies accordingly to provide a constant temperature to which the intake fuel mixtures are heated. Thus, the quality of the treated intake fuel mixtures is maintained throughout the range of operating conditions under which the engine must operate, from cold start to smooth operation at high speeds.

The device according to the invention also improves the treatment of the exhaust gases. The exhaust gases are hot enough to ignite hydrocarbons in the presence of oxygen.

Because the mixing ratio of the fuel mixture is poorer than the stoichiometric, the resulting exhaust gases contain excess oxygen.

The exhaust means retains the heat of the exhaust gases to maintain their temperature at or above the reaction temperature of the hydrocarbons with oxygen. This reaction generates additional heat in the exhaust means.

This results in the use of two separate heat sources. The heat from the exhaust gases fed to the thin-walled liner and the additional heat generated therein in the reaction of excess oxygen with unburned hydrocarbons. The additional heat generated is particularly important at low engine loads, with less exhaust gas flow and hence lower temperatures under these conditions. Heat retention is achieved by reducing heat transfer from the exhaust means at all locations except for the area where heat transfer occurs between the exhaust and intake means. There is a continuous combustion of hydrocarbons and maximum utilization of the heat contained in the exhaust gases. Thermal energy in the exhaust gas is used to maintain the reaction between unburned hydrocarbons and excess oxygen, to oxygenate the carbon monoxide to carbon dioxide, and finally to evaporate the fuel droplets in the fuel mixture in the intake means.

In summary, the device of the invention, an intake and exhaust system for internal combustion engines, wherein the exhaust gases are maintained above the minimum reaction temperature necessary to burn hydrocarbons and oxidize carbon monoxide to carbon dioxide, and which improve the quality of the fuel mixtures entering the engine. These favorable conditions are achieved shortly after the start. The relative temperatures between the fin wall portion associated with the secondary intake chamber and the fin wall between the exhaust and intake manifolds remain the same regardless of engine operating conditions.

When the engine is running, considerably less impurities are released into the atmosphere.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of the intake and exhaust means of the present invention;

1, FIG. 3 is a bottom view of the suction means with a partial section along line 3--3 of FIG.

Fig. 2 is a top plan view of the exhaust means with a partial sectional view taken along line 4--4 of Fig. 2; Fig. 5 is a perspective view of the exhaust means tubes of Fig. 4.

FIG. 2 shows an intake and exhaust assembly of an engine having a secondary combustion chamber 1 in each cylinder connected to each main combustion chamber 2.

In the engine head 3, the secondary suction channels 4 lead to the secondary combustion chambers 1.

A spark plug 5 is provided in each secondary combustion chamber 1 and the flame whirling duct 6 connects each secondary combustion chamber 1 to the main combustion chamber 2, respectively. The main combustion chambers 2 are bounded on one side by a movable wall formed by the face of the piston 7 arranged in the cylinder 8 of the cylinder block 9 of the engine. The main intake ducts 10 and exhaust ducts 11 are connected to each main combustion chamber 2 and are also located in the engine head 3. During the intake stroke of the piston 7, the rich fuel mixture is fed to the secondary combustion chamber 1 and the lean fuel mixture is fed to the main combustion chamber 2. After the compression stroke, the rich fuel mixture in the combustion chamber 1 is ignited by a spark plug. ejected through the flame duct 6 into the main combustion chamber 2 to ignite a lean fuel mixture. During the exhaust stroke, the flue gas is exhausted through the exhaust duct 11. When the exhaust gases leave the main combustion chamber 2, they have a temperature that is higher than the minimum temperature required for the reaction of unburned hydrocarbons and carbon monoxide with oxygen. Furthermore, the air / fuel mixing ratio in the intake fuel mixture is such that there is excess oxygen in the exhaust gas as they leave the main combustion chamber 2. Combustion of hydrocarbons and oxygenation of carbon monoxide continues when the exhaust gases leave the engine and enter the exhaust system .

The carburetor also works in conjunction with the intake and exhaust systems to produce two different fuel mixtures. The main carburetor 12 forms a lean fuel mixture which is led to the main combustion chamber 2 of the engine. The secondary carburetor 13 creates a rich fuel mixture for the secondary combustion chamber 1. The intake and exhaust system is shown in conjunction with the main carburetor 12 and the secondary carburetor 13, the engine head 3, in which the main combustion chamber 2 and the auxiliary combustion chamber 1 and exhaust pipe are located. The intake and exhaust system has two main parts, namely the intake means formed by the intake manifold 14 and the exhaust means formed by the exhaust manifold 15. The intake manifold 14 branches to a main intake manifold 17 and a secondary intake manifold 16. In the illustrated embodiment the main the suction line 17 and the secondary suction line 16 are in the form of a single casting. This design reduces costs and is suitable for mass production. The main intake manifold 17 consists of four main intake pipes 18 connected to the main intake ducts 10 of the engine head 3 opening into the main combustion chambers 2.

The main suction line 17 comprises a main suction chamber 20 from which the main suction tubes 18 extend.

The main suction chamber 20 is limited by a peripheral wall 22, an upper connecting flange 24 and a ribbed lower wall 84. In the peripheral wall 22 of the suction chamber 20 are formed lower openings 26 for connecting the main suction chamber 20 to the main suction tubes 18. the main carburetor 12, the connecting flange 24 is provided with passageways 28 for connecting the main carburetor 12 to the main suction line 20. The height of the main suction chamber 20 is given by the desired diameter of the main suction pipe 18, as shown in FIG. be too high for the intake fuel mixture to pass near its bottom where it is heated.

A secondary suction channel 30 is provided adjacent the main suction chamber 20, which connects the secondary carburetor 13 to the secondary suction chamber 32. The secondary suction chamber 32 forms part of the secondary suction line 16. The secondary suction tube 34 is connected to the secondary suction chamber 32 and the secondary suction channel 4. The secondary suction chamber 32 is smaller than the main suction chamber 20 because a small amount of rich fuel mixture passes through the secondary suction chamber 32 and a large amount of lean fuel mixture flows through the main suction chamber 20. The secondary suction chamber 32 is arranged below and to the side of the main suction chamber 20 as shown in FIG. 2. The secondary suction chamber 32 extends along the entire width of the main suction chamber 20 and is thermally connected thereto. The passages 38 connect the secondary suction chamber 32 to the secondary suction tubes 34.

The intake manifold 16 and main intake manifold 17 lead the rich and lean fuel mixture to the respective intake chambers 32, 20. From the intake chambers 32, 20, the intake pipes and intake ducts lead to the respective combustion chambers 1, 2 located in the engine head 3. The four side suction tubes 34 are connected by respective side combustion chambers 1, in a four-cylinder engine. The intake manifold 14 is connected to the engine head 3 via a gasket 40. The channels 4, 10 in the engine head 3 supply a rich and lean fuel mixture to the respective combustion chambers 1, 2.

The exhaust conduit 15 is disposed below the intake conduit 14. The exhaust conduit 15 is provided with an outer sleeve 42 that surrounds the inner liner 44. The outer sleeve 42 is a cast metal of gray cast iron or other similar material. To form this, an inner liner 44 is first produced on which molding material, such as sand, is applied to form the inner shape of the outer sleeve 42. The outer sleeve 42 is then cast in a conventional manner. To remove sand or other molding material from the space between the inner liner 44 and the outer housing 42, openings 43 are formed in the outer housing 42. The apertures 43 are provided with plugs 45 to close the outer housing 42.

The outer casing 42 is a support portion of the exhaust pipe 15 and at the same time serves to retain the heat of the exhaust gases. The outer sleeve 42 abuts the engine head 3, where it is secured by nuts 49. From the various exhaust ducts 11, the branches 31 of the exhaust manifold 15 extend to the central exhaust chamber 46, arranged directly below the main suction chamber 20 and the secondary suction chamber 32. a flange 50 of the outer casing 42, forming a connection between the central exhaust chamber 46 and the underside of the main suction chamber 20 and the underside of the secondary suction chamber 32. The neck 52 of the suction chambers 20, 32 abuts the flange 50 and is fastened by screws 53. between the flange 50 and the neck 52. The heat shield 54 protects the neck 52 from the heat from the outer housing 42. Furthermore, the heat shield 54 prevents direct radiation and heat flow between the exhaust manifold 15 and the carburetors 12, 13 located directly above it. A portion of the heat shield 54 between the neck 52 and the flange 50 serves as a seal to their connection.

The exhaust line 15 is separated from the suction line 14 to prevent heat transfer therebetween. The large amount of heat supplied to the intake manifold 14 causes the carburetors 12, 13 to overheat and reduces the amount of heat retained in the exhaust manifold 15. The outer housing 42 is extended downwardly from the central exhaust chamber 46 to connect the exhaust exhaust pipe 56. an exhaust manifold 56. The gasket 58 is disposed in a groove 60 between the outer housing 42 and the exhaust manifold 56, the groove 60 being located in the flange 61 of the exhaust manifold 56; the inner liner 44 surrounded by the outer casing 42 is formed of a thin refractory material, such as stainless steel.

The inner liner 44 is made of a material with a maximum thickness of 2 mm to have a low heat capacity. On the other hand, if the inner liner 44 is very thin, it will wear rapidly. In said arrangement according to the invention, the wall thickness of the inner liner 44 is 1.2 mm. The inner liner 44 forms a central exhaust chamber 62, which is disposed between the cylinder head 3 and the end exhaust manifold 56. The inner liner 44 is generally formed of two sheet metal parts of heat-resistant steel joined by a skirt 64. The cylindrical outlet tube 66 is extended downwardly from the central The flanges 64 terminate in the region of the inlet 65 of the inner liner 44 near the engine head 3 for manufacturing and assembly reasons.

The thin-walled inner liner 44 is spaced apart from the thick-walled outer sleeve 42 by a major portion of its surface. This creates an insulating air gap between the inner liner 44 and the outer sleeve 42. The low thermal capacity of the inner liner 44, due to its thin-walled construction, causes rapid heating of the inner liner 44 due to hot exhaust gases, without significant losses to the outer liner 42. On the inside of the flange 50 of the outer housing 42, a bearing surface is provided for attaching the inner liner 44 with the upper liner 68. The upper intermediate liner 68 is attached to the flange 50 by a fastening screw 70. The cover nuts 72 are screwed onto the fastening screws. 73 and serves to protect against corrosion and erosion. The fastening screws 70 are screwed into the cover nuts 72 before the outer sleeve 42 is cast around the inner liner 44. Typically, the fastening screws 70 are permanently fixed in the cover nuts 72 to secure the inner liner 44. The hole 74 in the inner liner 44 and the upper intermediate liner 68 is Thus, a significant portion of the heat transfer takes place between the central exhaust chamber 62 and the underside of the main and auxiliary intake chambers 20, 32.

The inner liner 44 is secured to the flange 50 of the outer casing 42 by the fastening screw 70. The lateral fastening is performed by the inlet 65 and the outlet via the outlet tube 66. The inner liner 44 extends through the exhaust manifold 76 of the outer casing into each of the exhaust ducts. The outer sleeve 42 is tapered to clamp the inner liner 44. There is little play between the inlet 05 and the outer sleeve 42. This allows the inner liner 44 to expand or contract freely through the outer sleeve 42 at different temperatures. When mounting the inner liner 44 in the middle position, the maximum change in position due to thermal expansion relative to the outer sleeve 42 is minimal. The inlet 65 of the inlet exhaust pipe 63 of the inner liner 44 projects somewhat into the engine head 3 (FIG. 2). This protrusion into the engine head 3 improves the seal between the engine head 3 and the exhaust manifold 15 and further provides centering of the inner liner 44 to minimize disturbance of the exhaust stream from the engine head 3 and its introduction into the exhaust manifold 15.

The outlet pipe 66, extended to the exhaust exhaust pipe 56, is not firmly attached to the outer casing 42 or the exhaust outlet pipe 56. The outer casing 42 is clamped around the outlet pipe 66. The first sealing rings 78 are disposed between the outer sleeve 42 and the outlet tube 66 to prevent exhaust gases from entering the gap between the inner liner 44 and the outer sleeve 42. The first sealing rings 78 are positioned to contact the inner wall of the recesses 77 of the outer sleeve 42 A second sealing ring 79 is disposed between the sealing rings 78, which seal with the outer surface of the outlet tube 66 but do not extend to the inner wall of the recess 77 of the outer sleeve 42. This creates considerable play between the outlet tube 66 and the outer sleeve 42. This allows manufacturing tolerance and thermal expansion. A retaining ring 75 is provided to keep the sealing rings 78, 79 in position. The outlet pipe 66 is extended to the end exhaust pipe 56 for greater leakage. This extension also centers the outlet pipe 66 relative to the end exhaust pipe 56.

In the central exhaust chamber 62 ^f is provided baffle 30 in order to direct the exhaust gases flowing upward openings 74, 48 into contact with the underside of the main suction chamber 20 and the auxiliary suction chamber 32. The baffle 80 is bent upwardly from the bottom of the central exhaust chamber 62 to which it is attached by a flange 82, closer to the upper end of the central exhaust chamber 62. The bulkhead 80 is also secured by catches 83 to the side wall of the inner liner 44. The bulkhead 80 is curved to direct the exhaust gases into the center of the aperture 74 as they move upwards. . The baffle 80 ensures that, at any load and engine speed, the exhaust gases pass upward toward the ribbed bottom wall 84 of the intake chambers 20, 32. The existence of the baffle 80 prevents any braking of the flowing exhaust gas. Such braking impedes the upward flow of hot gases for the inlet to the lower part of the intake chambers 29, 32. The height of the partition 80 relative to the lower walls of the intake chambers 20, 32 is determined empirically to guarantee good operation of this arrangement. If the baffle 80 is too low, the exhaust gases do not flow in the right direction up to the bottom wall of the intake chambers 20, 32. In this case, the fuel mixtures passing through the intake chambers 20, 32 are not sufficiently heated. Conversely, if the partition 89 is too high, the exhaust gases will overheat the intake chambers 20, 32 and hence the fuel mixture. Further, the baffle 80 limits exhaust flow through the central exhaust chamber 62. If the baffle 80 is too wide, then the central exhaust chamber 62 is excessively reduced and undesirable back pressure occurs in the system. In the arrangement according to the invention, the upper part of the partition 80 is 2.5 cm below the bottom wall of the main suction chamber 20.

To accommodate the upwardly moving exhaust gases, a wall is provided, which is the bottom wall of the secondary and main intake chambers 32, 20 formed as a fin wall 84. The lower fin wall 84 spatially separates the main intake chambers 20, 32 from the central exhaust chamber 62, is thermally connected between them. This creates a common wall of the intake and exhaust systems. The bottom rib wall 84 is integrally formed with a portion of the intake manifold 14 and of the same material; in the arrangement shown, an aluminum casting. On the underside of the fin wall 84, mutually perpendicular fins 86 are provided that extend along the length and across the lower portions of the suction chambers 20, 32. The fins 86 reinforce the fin wall 84 for considerable thermal stress during operation. The thickness of the wall 84 between the ribs 86 in the present arrangement is constant and is 4 mm. This thickness ensures minimal warm-up time and long service life.

The fin bottom wall 84 is formed from a common bottom wall material of the intake chambers 21, 32 to jointly change the operating portions in each of the intake chambers 20, 32. Typically, if the engine exhaust is cold, the main intake chamber 20 is cold. and, to the auxiliary intake chamber 32, a smaller amount of heat is transmitted through the fin wall 84. Conversely, if the engine exhaust is hot and passes rapidly through the exhaust line 15, both intake chambers 20, 32 will mediate a large heat transfer. As a result, variable variables, for example, the fuel ratio of the fuel mixture, need not be changed to accommodate the change in the range of operating conditions. The conditions of the main intake manifold remain consistent with the conditions of the secondary intake manifold under different modes. The uniform design of the ribbed bottom wall 84 also acts to increase the lifetime of the seal. The use of a single portion reduces recurring thermal shocks, resulting in a longer service life of the ribbed bottom wall 84. Another advantage is that the amount of heat supplied to both suction chambers 29, 32 is not the same. The auxiliary intake system is not dependent on the amount of fuel mixture in the main intake system. Usually, a smaller amount of heat transferred to the secondary suction system is required compared to the amount of heat transferred to the main suction system, while capturing the same effect. The ratio of the lateral ribbed wall regions 84 that are directly associated with the secondary suction chamber 32 and the lateral ribbed wall regions 84 that are associated with the main suction chamber 20 is selected to compensate for the difference in thermal requirements. The side region is defined by the horizontal portions of the ribbed bottom wall 84 and does not include its vertical portions either at its edges or along the sides of the secondary suction chamber 32. It has been found that a portion of the side surface of the ribbed bottom wall 84 associated with the suction chamber 32 lies within limits. 0.2 to 0.4 of the entire side surface of the ribbed bottom wall 84; associated with both suction chambers 20, 32, i.e., the side surface of the ribbed bottom wall 84, associated with the secondary suction chamber 32, should be within 1/4 to 2/3 of the side surface associated with the main suction chamber 20. Thus, the temperature of the ribbed bottom The wall 84 remains constant along the secondary suction chamber 32. and the main suction chamber 20. While maintaining the dimensions of the fin bottom wall 84 at a predetermined size, the thermal conditions of the fin bottom wall 84 between the main and secondary suction chambers 20, 32 remain within the range of the cold start. until the engine is fully loaded. In addition, this ratio of the ribbed bottom wall regions 84 eliminates the need to alter the carburetor adjustment as the operating conditions of the system change.

The location of the secondary suction chamber 32 below the main suction chamber 20 therefore affects the amount of heat transferred to the suction chambers 20, 32. The surface of the ribbed bottom wall. 84, associated with the secondary suction chamber 32, is disposed about 1.5 cm below the surface of the ribbed bottom wall 84 associated with the main suction chamber 20. Also, the location of the top of the partition 80 below the ribbed bottom wall 84 affects the amount of heat transfer to Each suction chamber 20, 32. The arrangement according to the invention has a vertical surface between the two lateral surfaces of the ribbed bottom wall 84 separated from the center of the apex of the baffle 80 by about 3.75 to 4 cm gap. together, the intake chambers 20, 32 together determine constant thermal conditions between the main and the intake chambers 20, 32 even when the exhaust gas temperature and flow rate change. This assembly also together creates stable thermal conditions in. ribbed bottom wall 84. If the pipe system is heated after a cold start, then the ribbed bottom wall 84 has a temperature of about 200 ° C. It is desired to maintain the temperature of the fin bottom wall 84 below the main suction chamber 20 and the secondary suction chamber 32 in the range of from 160 ° C to 260 ° C. In this range, the fuel in the fuel mixture is vaporized prior to ignition in the combustion chamber. Further, if the temperature of the fin bottom wall 84 is too high, then the fuel in the secondary suction tube 34 is prematurely charred. Also, the carburetors 12, 13 overheat due to their connection to the superheated intake manifold 14, which makes it difficult to start a warm engine. By maintaining the temperature of the ribbed bottom wall 84 in a small variation during engine operation, a longer service life of the ribbed bottom wall 84 is achieved.

The specified temperature range is kept constant over a wider range of operating conditions when the engine is warmed up once after a cold start. If the exhaust gases have a higher temperature and flow rate, more heat is transferred to the fin bottom wall 84. At the same time, however, the amount of cold fuel mixture is increasing. Thus, typically, more of the accumulated heat of the exhaust gas is in the finned bottom. wall 84 is removed by the fuel mixture. The described arrangement 'is designed to achieve a balance between the heat accumulated in the fin bottom wall 84' and the heat extracted therefrom, so that this desired ratio can be maintained under a wide range of engine operating conditions.

The central exhaust chamber 62 has another function of controlling the temperature of the exhaust gases. The exhaust gases expelled from the main combustion chamber 2 have a temperature that is higher than the temperature necessary for the continuous combustion of hydrocarbons and the oxidation of carbon monoxide, which form undesirable exhaust gas components. Further, the combined rich fuel mixture and the lean fuel mixture form an overall mixture that is poorer than the stoichiometric ratio. As a result, there is an excess of oxygen in the exhaust gas. Excess oxygen acts in reaction with hydrocarbons and carbon monoxide at a temperature higher than the temperature at which the combustion and oxidation of these components take place by continuously converting the undesirable components into water and carbon dioxide.

For maximum conversion of hydrocarbons and carbon monoxide into water and carbon dioxide, it is desirable to maintain the exhaust gas at elevated temperature as it passes through the exhaust manifold. The air insulation between the outer casing 42 and the inner liner 44 creates conditions in which the temperature of the exhaust gases is not only maintained, but continuously acts on the thermal reactions of their components. It has been found advantageous to control the volume of the central exhaust chamber 62 as a function of engine load, in order to optimize the maximum conversion of polluting hydrocarbons and carbon monoxide into water and carbon dioxide. If the central exhaust chamber 62 is too large, it is difficult to control the temperature in the inner liner 44 on the ribbed bottom wall 84. This further affects the extremely long heating time of the exhaust pipe 15. If the central exhaust chamber 62 is too small, the exhaust gases pass through into the final exhaust manifold 56 before the hydrocarbons and carbon monoxide are burned and oxidized. The volume of the inner liner 44 given by the vertical plane 87 touching the inner convex surface 88 of the inner liner 44 and the inlet opening 89 of the outlet tube 66 determines the size of the central exhaust chamber 62. The contents of the central exhaust chamber 62 is further delimited by the plane of the lower surface of the upper intermediate liner 68. that it is appropriate that the ratio of the central exhaust

Claims (11)

PKEDMĚT An apparatus for fuel mixture intake and flue gas exhaust for internal combustion engines with at least two cylinders, having an auxiliary combustion chamber connected to each main combustion chamber by a flame throat channel, comprising suction means comprising an intake manifold extending from the main intake chamber for supply lean fuel mixture to each engine main combustion chamber, an auxiliary intake chamber with at least one intake manifold extending from the auxiliary intake chamber, for supplying a rich fuel mixture to each engine auxiliary combustion chamber, and exhaust means formed by an exhaust duct for exhausting flue gas from each main combustion an engine chamber into an exhaust pipe, characterized in that the exhaust means comprises a thin-walled inner liner (44) surrounded with a gap silnoutennyin the outer casing (42), the thin-walled inner liner (44) being provided with plaques 62 and engine contents, was 0.5 to 0.9. The conditions in the exhaust pipe 15 can be controlled within this range. The exhaust gases are largely free of hydrocarbons and carbon monoxide. This is important not only so that the exhaust gases are freed of unwanted constituents after the engine has reached stable operating conditions, but also that these steady engine operating conditions are reached quickly. Tests of an engine with such an arrangement have shown that an acceptable emission level was reached in less than 1 minute. after start. This heating time rate can be accomplished by combining some properties that also act to maintain the same output of the exhaust manifold 15. In particular, the exhaust manifold 15 is designed to have minimal thermal uptake of the incoming exhaust gases so that the exhaust manifold 15 is rapidly heated for continuous combustion. hydrocarbons and carbon monoxide. These conditions can be easily realized if the walls of the inner liner 44 are thin and its content is small. Further, the exhaust gases are directed upwardly by the baffle 80 to provide contact of the hot exhaust gas with the fin bottom wall 84. The location of the secondary intake chamber 32, extended toward the exhaust manifold 15, ensures rapid heating of the rich fuel mixture passing therethrough. The ability of the system to maintain a constant temperature in the ribbed bottom wall 84 during operation is not effective. The ribbed bottom wall 84 is aluminum, of optimum wall thickness, to increase the rate of heat transfer. Consequently, the intake manifold 15, after a cold start, operates quickly to provide suitable thermal conditions in the inner liner 44 and the ribbed bottom wall 84 to transfer heat to the fuel mixture. YNALEZU with at least one inlet exhaust pipe (63) and an outlet pipe (66) for evacuating exhaust gases from each main combustion chamber (2) and forms a central exhaust chamber (62) having an opening (74) to which a portion of the suction means formed a ribbed bottom wall (84) of the main suction chamber (20) and a secondary suction chamber (32), wherein a portion of the ribbed bottom wall (84) of the secondary suction chamber (32) forms 1/4 to 2/3 of the effective area of the ribbed bottom wall (84) ) of the main suction chamber (20). Suction and exhaust system according to claim 1, characterized in that the suction means are formed by the suction line (14) and the exhaust means by the exhaust line (15). Intake and exhaust system according to claim 1 or 2, characterized in that the thin-walled inner liner (44) is of heat-resistant steel and the thick-walled outer casing (42) is of cast iron. 4. Intake and exhaust system according to items 1 1 to 3, characterized in that the inner liner (44) is made of a refractory sheet. An intake and exhaust device according to any one of claims 1 to 4, characterized in that the opening (74) of the thin-walled liner (44) of the exhaust pipe (15) and the opening (48) of the thick-walled outer casing (42) lie opposite the ribbed bottom wall (84). ) main suction chambers (20) and secondary suction chambers (32). 6. Intake and exhaust system according to claim 5, characterized in that the thick outer wall (42) has a flange (50) in which an opening (48) is provided and the thin-walled insert (44) is provided with an intermediate lining (68) with an opening (74). ) coaxial to the opening of the thin-walled insert (44), the intermediate insert (68) with the thin-walled insert (44) being connected to the flange (50) by fastening screws (70). Suction and exhaust system according to any one of claims 1 to 6, characterized in that a baffle (80) directed towards the ribbed bottom wall (84) of the main suction chamber (20) and the secondary suction chamber is provided in the central exhaust chamber (62). (32). 8. Intake and exhaust system according to claim 1, characterized in that the ribbed lower wall (84) of the main suction chamber (20) and the secondary suction chamber (32) has two parts forming a common bottom of the main combustion chamber (20) and the lower part. secondary combustion chambers (32). 9. Suction and exhaust system according to claim 1, characterized in that the distance of the portion of the finned bottom wall (84) of the secondary suction chamber (32) from the intermediate lining (68) of the thin-walled insert (44) is less than ) of the main suction chamber (20) from the intermediate liner (68). The intake and exhaust system of claims 1 to 9, wherein each inlet exhaust pipe (63) and each outlet pipe (66) of the thin-walled inner liner (44) is housed in a thick-walled outer casing (42), the thin-walled liner (42). 44) is held against the thick-walled outer housing (42) by fastening screws (70). Intake and exhaust system according to one of Claims 1 to 10, characterized in that the volume of the thin-walled inner liner (44) is between 0.5 and 0.9 of the engine content.