RU97446U1 - SMALL DIFFUSER FOR TWO-CHAMBER CARBURETOR - Google Patents

Abstract

 1. A small diffuser made in the form of a tube, the inner cavity of which has a throat, cylindrical and conical parts, and the outside of the side surface of the tube of a small diffuser is connected to the sides of two ribs elongated along the direction of air flow, having rounded front edges and rectangular flanges on opposite sides, in one of the ribs there is an emulsion channel extending into the cylindrical section of the inner cavity of the tube of the small diffuser, the correct part is made in the upper part of the same rib a supply channel providing air to the emulsion channel of the small diffuser, characterized in that the rounded front edge of the rib is conjugated with the middle part of the rib, the side walls of which are mainly parallel and are connected with the tip of the rib having a convex streamlined shape, the cavity of the tube of the small diffuser is made with a minimum the diameter of the inlet neck d1 equal to (7.5 ± 0.5) mm, and its cylindrical section has a diameter d2 equal to (10.1 ± 0.6) mm, the emulsion channel of the small diffuser has a minimum and diameter d3 equal to (3.4 ± 0.4) mm, with a diameter of the correction channel d4 equal to (0.7 ± 0.2) mm. ! 2. The small diffuser according to claim 1, characterized in that the ratio of the thicknesses of the ribs of the small diffuser to each other satisfies the condition! 1.6 <T1 / T2 <2.1 at T1 from 5.5 to 6.2 mm,! where T1 is the thickness of the ribs with emulsion channel,! T2 - rib thickness without emulsion channel. ! 3. The small diffuser according to claim 1, characterized in that the emulsion channel has a variable diameter with a transitional conical section, into which a vertically located correction channel in the rib, made with an input

Description

The utility model relates to the field of engine building, namely to the components of the main air path of two-chamber carburetors, in particular to small diffusers.

The perfection of a modern carburetor is largely determined by how accurately it maintains the necessary composition of the mixture in all operating conditions of the engine. The necessary composition of the combustible mixture is determined by: the design of the carburetor, the parameters of the air-fuel tract, which includes a system of diffusers with the optimal choice of metering elements, which can improve the dosage of the fuel emulsion. To solve this problem, small diffusers are used, which are installed in the body of the two-chamber carburetor along the axis of the main air path and partially go inside the large diffusers, which allows to increase the vacuum inside the small diffuser. Two-chamber carburetors with a diffuser system of this design are designed for engines with a volume of 1 to 3 liters.

Small diffusers are made in the form of a tube, the inner cavity of which has a throat, a cylindrical section and a conical part, outside the small diffusers are equipped with two supporting ribs. In one of the ribs perform an emulsion channel for supplying fuel emulsion to the main air path. In particular (Andreev V.I., Volin S.N., Goryachiy Ya.V., Chernyak B.Ya. Distribution of the mixture in the carburetor engine. M., "MECHANICAL ENGINEERING", 1966, Fig. 50, p. 114 ) a diffuser is proposed, having ribs with a rounded leading edge, a wedge-shaped tip and a sharp trailing edge, the presence of which will lead to the formation of disturbances in the air stream flowing around the fins of the small diffuser, which can lead to additional local braking of the air flow and a violation of the stability of mixture formation in the main air carburetor path, h This will reduce engine filling when the throttle is fully open.

The applicant in patent No. 2173786 proposed a small diffuser with a vertical correcting channel in the upper part of the rib, providing air to the emulsion channel of a small diffuser. The use of a correction channel prevents the pulsating (projectile) flow in the emulsion channel, which is characterized by a strong non-uniformity of fuel supply, at certain carburetor operating modes. An annular ledge in the tube cavity of the small diffuser between the inlet neck and the cylindrical part of the tube allows for turbulence of the air flow when it enters the exit zone of the fuel emulsion in the cylindrical part of the tube cavity, where it is crushed, which is especially important at low air flow velocities when energy is not enough for high-quality atomization of fuel.

However, an analysis of the operating experience of small diffusers and the experimental work on the selection of the geometric parameters of the channels of a small diffuser for the K-151 carburetor showed that the small diffusers used lead to a partial deterioration in the correspondence of the mixture composition to the engine operating mode, which affects its power and economic indicators, and also causes a change in the content of toxic substances in the exhaust gas.

The objective of the proposed utility model is to reduce the energy loss of the air flow in the main air path, increase the degree of regulation of the dual-chamber carburetor, which allows to improve the power and economic performance of the engine, as well as reduce the content of toxic substances in exhaust gases.

A small diffuser made in the form of a tube, the inner cavity of which has a throat, cylindrical and conical parts. Outside, the side surface of the small diffuser tube is connected to the sides of two ribs elongated along the direction of air flow, having rounded front edges and rectangular flanges on opposite sides. An emulsion channel is made in one of the ribs, which extends into a cylindrical section of the inner cavity of the small diffuser tube, and a correction channel is made in the upper part of the same rib, which ensures air to enter the emulsion channel of the small diffuser.

In accordance with the utility model, the rounded front edge of the rib is conjugated with the middle part of the rib, the side walls of which are mainly parallel and are conjugated with the tip of the rib having a convex streamlined shape, the cavity of the small diffuser tube is made with a minimum diameter of the inlet neck d1 of 7.5 ± 0 5 mm, and its cylindrical section has a diameter d2 equal to 10.1 ± 0.6 mm, the emulsion channel of the small diffuser has a minimum diameter d3 equal to 3.4 ± 0.4 mm, with a diameter of the correction channel d4 equal to 0, 7 ± 0.2 mm.

Using the proposed profile of the ribs allows the air flow to more evenly flow around the ribs of the small diffuser, starting from the upper cylindrical edge, then along the parallel walls connected by a convex streamlined tip, without creating disturbances in the region of the bottom edge of the ribs, which, accordingly, reduces the energy loss of the air flow during its passage through the main airway. Using the ribs of the proposed profile allows you to increase the degree of carburetor regulation by increasing the filling of the engine cylinders with fully open carburetor throttles.

An analysis by the Applicant of the operating experience of small diffusers of known design and the results of experimental studies with various versions of the small diffuser made it possible to clarify the boundary values for the diameters of the inlet neck and the cylindrical part of the internal cavity of the small diffuser, as well as the diameters of the openings of the emulsion and correction channels, allowing to improve the degree of carburetor adjustment all engine operating modes.

The results of tests on the engine at partial loads revealed that the implementation of the tube cavity of a small diffuser with a minimum diameter of the inlet neck d1 is less than 7 mm, and its cylindrical section with a diameter of d2 more than 10.6 mm (a large annular step) will lead to a significant increase in air turbine flow, which will increase its braking at high speeds, causing a drop in engine power.

If the cavity of the small diffuser tube is satisfied with a minimum diameter of the inlet neck d1 greater than 8 mm, and its cylindrical section with a diameter d2 less than 9.5 mm (small size of the annular ledge), then turbulization of the air flow will not be effective enough, which will lead to a deterioration in fuel atomization at the beginning of operation main dosing system, and an increase in the content of unburned hydrocarbons in the exhaust gases and a slight decrease in engine power in this mode.

If the diameter d3 of the emulsion channel of the small diffuser is less than 3 mm, this will lead to an insufficient supply of fuel through the emulsion channel at a higher rotational speed of the crankshaft and a large angle of rotation of the throttle valves, which will lead to unstable operation of the engine and loss of its power in the corresponding modes.

If the diameter d3 of the emulsion channel of the small diffuser is more than 3.8 mm, this will lead to an excessive increase in the supply of the fuel emulsion to the main air channel, and over-enrichment of the fuel-air mixture with fuel, an increase in CO and CH emissions, and a decrease in engine power due to deterioration combustion conditions in the engine cylinders.

The choice of the diameter of the correction channel d4 in the specified range can further improve the coupling of the main dosing system and the idle system.

If the correction channel has a diameter of less than 0.5 mm, this will lead to the early entry into operation of the main metering system, which in turn will lead to an increase in the content of carbon monoxide in the exhaust gases at an increased frequency of idling and mass emissions of CO when the car is moving in urban environments.

If the correction channel has a diameter greater than 0.9 mm, this will lead to the late entry into operation of the main metering system, a failure occurs in the engine, the vehicle’s driving performance deteriorates when, when you press the gas pedal, the power set does not correspond to the angle of the gas pedal , and mass emissions of CH increase. In addition, an increase in the diameter of the correction channel will lead to a deterioration in the working conditions of the main air jet, intended for the preparation of a fuel emulsion in an emulsion well.

The choice of the ratio of the thicknesses of the ribs of the small diffuser among themselves satisfying the condition:

1.6 <T1 / T2 <2.1 when T1 is in the range from 5.5 to 6.2 mm, where

T1 is the thickness of the ribs with an emulsion channel,

T2 - rib thickness without emulsion channel;

on the one hand, it allows the emulsion channel of the required cross section to be made with a wall thickness sufficient for long-term use of the product, on the other hand, the selected range limiting the difference between the thickness of the ribs prevents the negative effect associated with the different nature of the flow of ribs around the ribs, which ultimately affects uniformity of fuel atomization in the main air channel of the carburetor.

The emulsion channel of the diffuser can be made of variable diameter, with a transitional conical section, into which a vertically located correction channel in the rib comes out, made with an input chamfer, which makes the flow of the fuel emulsion more uniform.

The most optimal is the relationship between the outer diameter of the tube of the small diffuser and the distance from the tube axis to the center of the correction channel, satisfying the condition:

9.95 <d5 / L1 <1.15, where

d5 is the outer diameter of the tube,

L1 is the distance from the tube axis to the center of the correction channel.

It is possible to design a small diffuser with a lead-in profile made as parts of a circular segment with a sharp lead-in edge, with a ratio of the profile radius to the height of the lead-in neck satisfying the ratio

0.93 <R / H <1.13, where

R is the radius of the profile of the inlet,

H is the height of the inlet cavity of the neck.

The inlet neck of the small diffuser can be manufactured with an additional cylindrical section made in the form of a calibrated hole, which provides more stable rarefaction parameters of air in the small diffuser during mass production.

The implementation of the ribs with a length not exceeding half the length of the tube of the small diffuser allows for reliable installation of the small diffuser in the main air channel of the carburetor and to improve the character of the air flow around the edges of the small diffuser.

It is rational to place the ribs of a small diffuser in the same plane M passing through the axis N of its tube.

The upper edge of the ribs may be spaced from the upper edge of the tube at a distance of 0.10-0.18 from the length of the tube of the small diffuser.

The optimal small diffuser with the ratio of the height H of the inlet neck of the small diffuser to its minimum diameter corresponds to the condition

0.9 <H / d1 <1.1, where

H is the height of the inlet neck of the inner cavity of the tube of the small diffuser.

During the experiments, the optimal ratio of the height of the inlet neck of the small diffuser to the value of its minimum diameter was additionally established. The proposed ratio is optimal, since if the neck is too long, the dimensions of the small diffuser increase and resistance to movement of the air flow in the inlet neck increases, if the neck is too short, the perturbations increase and the air flow stops at the inlet of the inlet.

The utility model is disclosed below with reference to the accompanying drawings, in which:

Fig. 1 shows a small diffuser in longitudinal section along the MM plane;

Fig. 2 shows section AA, which shows the profile of the fin of a small diffuser;

Fig. 3 shows a top view of a small diffuser;

Fig. 4 shows a section BB, which shows the profile of the ribs of a small diffuser with emulsion and correction channels;

Fig. 5 shows a section MM of a small diffuser with the designation of the dimensions of the structural elements;

Fig. 6 shows a section through the body of a two-chamber carburetor with a small diffuser installed in its chamber.

An example of a preferred embodiment of a utility model.

The small diffuser 1 (Fig. 1-5) is made in the form of a tube 2, the inner cavity of which has a throat 3, a cylindrical section 4 and a conical part 5 located on the same axis N. The throat 3 has an additional cylindrical section 6, made in the form of a calibrated holes. Between the neck 3 and the cylindrical part 4 there is an annular ledge 7. The tube 2 of the small diffuser 1 is equipped with two bearing ribs 8, 9 located in one plane M passing through the axis N of the tube 2.

The ribs 8, 9 have a biconvex symmetrical streamlined profile relative to the plane M, elongated along the direction of air flow P. The ribs 8, 9 have in the upper part, in the direction of the air flow, a rounding 10 of a cylindrical shape, conjugated with the middle part of the ribs 8, 9, during which their side walls 11 are predominantly parallel and are connected to the tip 12 of the ribs 8, 9. Rib 9 has a large thickness and in it at an angle to the axis N made emulsion channel 13.

The emulsion channel 13 has an inlet 14 of a larger diameter connected to the outlet 15 of a smaller diameter by means of a transition 16, which is a truncated cone. A vertical correction channel 17 located in the M plane with a chamfer 18 at the entrance enters the transition cavity 16 of the emulsion channel 13.

On the opposite sides of the ribs 8, 9 there are rectangular flanges 19, which serve to install a small diffuser 1 in the main air duct 20 and fasten it in the grooves 21, 22 of the housing 23 of the two-chamber carburetor using a spring 24.

The small diffuser has the following dimensions (Fig. 3, 5): d1 = 7.5 mm, d2 = 10.0 mm. d3 = 3.5 mm, d4 = 0.7 mm, T1 = 6 mm, T2 = 3.2 mm. d5 = 14 mm, L1 = 13.5 mm, R = 7.5 mm, H = 7.3 mm.

A two-chamber carburetor with a small diffuser of the proposed design works as follows (Fig. 6.). When the engine is running, the vacuum through the inlet pipe (not shown) connecting the engine to the carburetor is transferred to the carburetor intake pipe (not shown), where air flow P is formed, flowing in the inlet cavity 25 of the large diffuser 26 of the main air path 20, as through the cavity tube 2 of the small diffuser 1, and around its outer surface, along its ribs 8, 9 and further falling into the large diffuser 26 of the main air path 20 of the carburetor. The exit of the conical part 5 of the tube 2 of the small diffuser 1 is located in the narrow part of the large diffuser 26, which increases the vacuum inside the tube 2 of the small diffuser 1. As a result, due to the resulting pressure difference, the fuel “T” from the float chamber 27 through the fuel nozzle 28 enters emulsion well 29, where, using the emulsion tube 30, it is mixed with air entering through the air jet 31. In the emulsion well 29, the fuel emulsion “E” is formed, which enters the emulsion channel 13, a small diffuser 1, into which a small part of the air flow “P” enters through the correction channel 17, where it mixes with the fuel emulsion, preventing the appearance of a “shell” flow regime in the emulsion channel 13. Next, the fuel emulsion through the outlet 15 of the emulsion channel 13 enters the cylindrical cavity 4 of the small diffuser 1, where it begins to be crushed by the air flow "P", which continues at the outlet of the small diffuser, then in the large diffuser and the mixing chamber (not shown) of the carburetor, from where uniformly dusty air-fuel mixture through the inlet pipe nozzles enters the engine cylinders.

The small diffusers offered in accordance with this utility model have proven themselves in the operation of the K151C, K151Ts and K172 dual-chamber carburetors produced by the applicant, the vehicle’s driving performance has improved, and the content of toxic substances in the exhaust gases has decreased. Statistical studies revealed an increase in the stability of the carburetor parameters when removing the throttle characteristic in accordance with the requirements of the applicant's specifications.

Claims (10)

1. A small diffuser, made in the form of a tube, the inner cavity of which has a throat, cylindrical and conical parts, and on the outside the side surface of the tube of a small diffuser is connected to the sides of two ribs elongated along the direction of air flow, having rounded front edges and rectangular flanges on opposite sides, in one of the ribs there is an emulsion channel extending into the cylindrical section of the inner cavity of the tube of the small diffuser, the correct part is made in the upper part of the same rib a supply channel providing air to the emulsion channel of the small diffuser, characterized in that the rounded front edge of the rib is conjugated with the middle part of the rib, the side walls of which are mainly parallel and paired with the tip of the rib having a convex streamlined shape, the cavity of the tube of the small diffuser is made with a minimum the diameter of the inlet neck d1 equal to (7.5 ± 0.5) mm, and its cylindrical section has a diameter d2 equal to (10.1 ± 0.6) mm, the emulsion channel of the small diffuser has a minimum and diameter d3 equal to (3.4 ± 0.4) mm, with a diameter of the correction channel d4 equal to (0.7 ± 0.2) mm. 2. The small diffuser according to claim 1, characterized in that the ratio of the thicknesses of the ribs of the small diffuser to each other satisfies the condition 1.6 <T1 / T2 <2.1 at T1 from 5.5 to 6.2 mm, where T1 is the thickness of the ribs with an emulsion channel, T2 - rib thickness without emulsion channel. 3. The small diffuser according to claim 1, characterized in that the emulsion channel has a variable diameter with a transitional conical section, into which a vertically located correction channel in the rib comes out, made with an input chamfer. 4. The small diffuser according to claim 1, characterized in that the ratio between the outer diameter of the tube and the distance from the tube axis to the center of the correction channel satisfies the condition 0.95 <d5 / L1 <1.15, where d5 is the outer diameter of the tube, L1 is the distance from the tube axis to the center of the correction channel. 5. The small diffuser according to claim 1, characterized in that the profile of the inlet neck is made as part of a circular segment and has a sharp inlet edge, while the ratio of the radius of the profile to the height of the inlet neck satisfies the ratio 0.93 <R / H <1.13, where R is the radius of the profile of the neck, N is the height of the inlet cavity of the neck. 6. The small diffuser according to claim 1, characterized in that the inlet neck has an additional cylindrical section made in the form of a calibrated hole. 7. Small diffuser according to claim 1, characterized in that the length of the ribs does not exceed half the length of the tube of a small diffuser. 8. The small diffuser according to claim 1, characterized in that the ribs of the small diffuser are located in the same plane M passing through the axis N of its tube. 9. The small diffuser according to claim 1, characterized in that the upper edge of the ribs is spaced from the upper edge of the tube by a distance of 0.10-0.18 of the length of the tube of the small diffuser. 10. The small diffuser according to claim 1, characterized in that the ratio of the height H of the inlet neck of the small diffuser to its minimum diameter corresponds to the condition 0.9 <H / d1 <1.1, where H is the height of the inlet neck of the inner cavity of the tube of a small diffuser,