RU96183U1 - CARBURETTOR FOR ICE WITH A SLIT OUTLET IN THE MIXING CHAMBER - Google Patents

Abstract

 1. A carburetor for an internal combustion engine containing at least one mixing chamber with a throttle valve, a diffuser installed in the main air channel of the carburetor, having a spray gun in communication with the float chamber through the main metering system, and an idle system, the channel of which has a vertical outlet a slot hole located in the wall of the mixing chamber, characterized in that the slot hole in the wall of the channel of the mixing chamber is made from 4 to 5 mm long and is positioned in this way m, that with a fully closed throttle valve with a thickness of 0.8 to 1.2 mm until the edge stops in the wall of the mixing chamber, the throttle valve divides the exit slot in the wall of the mixing chamber into two unequal parts located above and below the valve, with the ratio between the length of the part of the slit located above the fully closed throttle to the entire length of the slit, which is in the range of 0.62-0.78. ! 2. A carburetor for an internal combustion engine according to claim 1, characterized in that the lower edge of the slotted hole is at a distance of not more than 0.5 mm from the lower edge of the fully closed throttle. ! 3. The carburetor for the internal combustion engine of claim 1, characterized in that the installation angle of the fully closed throttle valve relative to the plane perpendicular to the axis of the main air path is 7-13 degrees.

Description

The invention relates to mechanical engineering, in particular to carburetors for internal combustion engines.

A known carburetor for an internal combustion engine [1], comprising at least one mixing chamber with a throttle valve, an atomizer of the main metering system located in the diffuser and in communication with the float chamber, and a channel of the idle system with two outlet openings located in the wall of the mixing chamber in which at least one longitudinal recess is made. Both openings of the idle system are located above the closed throttle. The outlet openings of the idle system of the carburetor intensively work at engine operating conditions corresponding to the movement of the car in urban conditions at speeds up to 60 km / h with constant stops and acceleration. The disadvantages of this carburetor is the presence of a longitudinal recess (or recesses) which complicates the design of the carburetor and its manufacturing technology. The presence of two outlet openings does not allow to achieve a smooth transition from the idle system to the main dosing system due to a jump-like change in the area of the passage section of the idle system outlet openings as the throttle opens.

A K88A type carburetor is also known for ZIL - 130 (2) car engines with idle systems with throttle mixture formation, which have an outlet made in the form of a narrow vertical slot located above the edge of the closed throttle valve. Such an arrangement of the outlet of the idling system does not guarantee the absence of failures in the engine at minimum opening angles of the throttle valves and impairs the driving performance of the car when starting. This disadvantage is usually compensated by the enrichment of the air-fuel mixture by changing the diameter of the nozzles of idle systems, which leads to an increase in fuel consumption and mass emissions of harmful substances, especially unacceptable for passenger car engines.

The closest to this utility model are carburetors manufactured by OJSC DAAZ. There are known designs of SOLEX carburetors (2108, 21083, etc.) that use the classic idle system with throttle mixture formation (3). These carburetors contain at least one mixing chamber with a throttle and a diffuser mounted in the main air channel of the carburetor. The carburetor diffuser has a spray gun in communication with the float chamber through the main metering system and the idle system. The idle system channel has an outlet vertical slotted hole located in the wall of the mixing chamber in the throttle zone. The throttle valve, as it opens, depending on the carburetor operating mode, changes the ratio between the air coming from the main air channel to the idle channel through the part of the vertical outlet slot located above the throttle valve and the fuel emulsion flowing from the part of the vertical outlet slot located under the throttle. A significant drawback of this carburetor design is the non-optimal choice of the geometrical dimensions of the slit and the location of the outlet slit hole relative to the throttle edge, which leads to a deterioration in the interaction of the idle system and the main carburetor system, causing a deterioration in the ride quality of the car, increased emission of harmful substances in the form of carbon monoxide and unburned hydrocarbons and increased operating costs of fuel when driving in urban conditions.

The objective of the utility model is to improve driving performance, reduce operating fuel consumption and mass emissions of harmful substances with engine exhaust when the car is moving in urban conditions by improving the interaction of carburetor dosing systems in transient engine and car operation.

Known carburetor for an internal combustion engine containing at least one mixing chamber with a throttle and a diffuser installed in the main air channel of the carburetor. The diffuser has a spray gun in communication with the float chamber through the main metering system and the idle system, the channel of which has an outlet slot located in the wall of the mixing chamber. In accordance with the utility model, the slotted hole in the wall of the channel of the mixing chamber is made from 4 to 5 mm long and is located in such a way that when the throttle is completely closed, with a thickness of 0.8 to 1.2 mm, until its edge abuts against the mixing wall chamber, the throttle valve divides the output slit hole in the wall of the mixing chamber into two unequal parts located above and below the valve. In this case, the ratio between the length of the part of the slit located above the completely closed throttle valve to the entire length of the slit is in the range of 0.62-0.78.

The most optimal start of carburetor operation is achieved provided that the lower edge of the slotted hole is at a distance of no more than 0.5 mm from the lower edge of the fully closed throttle. If the slit hole extends under the throttle by more than 0.5 mm, then this makes it impossible to adjust the carbon monoxide (CO) content in the exhaust gases at a minimum idle speed in accordance with legislative standards or the requirements of the manufacturer.

The most optimal angle between a fully closed throttle and a plane perpendicular to the axis of the main air path is in the range from 7 to 13 degrees. If the installation angle of the throttle valve is less than 7 degrees, then when assembling the carburetor, the probability of jamming of the valve significantly increases due to the stop of its edge against the wall of the mixing chamber. With an initial throttle angle of more than 13 degrees, the interaction of the carburetor dosing systems will deteriorate due to the narrowing of the range of the valve’s stroke from the partially blocked slot to the position where the slot is completely under the upper edge of the butterfly valve, which will require a significant increase in the length of the slot and will negatively affect the work idle systems.

The utility model provides a smooth entry into operation of the main dosing system during operation of the idle system and obtaining the optimal dosing characteristics (optimal fuel consumption) at the beginning of the throttle characteristic. This is ensured by the manufacture of a carburetor with the following conditions:

- the length of the slit in the wall of the channel of the mixing chamber is 4-5 mm;

- Throttle thickness 0.8-1.2 mm;

- a completely closed throttle valve divides the output slot in the wall of the mixing chamber into two unequal parts;

- the ratio of the length of the part of the slit located above the damper to the length of the entire slit is in the range of 0.62-0.78.

If the slit hole does not partially extend under the fully closed throttle, this will lead to an unacceptable deterioration in the ride quality of the vehicle when starting from a place in the form of a deep failure until the engine stops.

Filling the gap with an improper length and / or violating the location of the gap relative to the closed throttle (i.e., not complying with a ratio of 0.62-0.78) can lead to a change in fuel consumption (re-enrichment or over-depletion) at the established air flow rates up to permissible norms, which was confirmed during experiments on the selection of optimal ratios between the long slit and its location relative to the throttle, the results of which are given below.

If the thickness of the throttle is less than 0.8 mm, then this causes technological difficulties in performing it in production and maintaining the required rigidity of the shape of the throttle, which can be deformed during long-term operation of the carburetor with a flap of smaller thickness.

If the thickness of the throttle valve is more than 1.2 mm, then the height of its end increases, which reduces the effective length of the slit with an adjustable flow of fuel and air.

Figure 1. Schematic illustration of a carburetor.

Figure 2. Schematic representation of a cross section of a mixing chamber of a carburetor with an exit slot in an idle system.

In figure 3. and FIG. 4. presents the throttle characteristics of the carburetor at different lengths of the slotted hole in the mixing chamber and different positions of the slotted hole relative to the initial position of the throttle in the mixing chamber.

The carburetor (see Fig. 1) contains a mixing chamber 1 with a throttle valve 2, above the mixing chamber 1 there is a large diffuser 3 of the main air channel with an inlet neck, inside which a small diffuser 4 with a spray 5 connected through the emulsion channel 6 and emulsion is installed well 7 of the main dosing system with a float chamber 8.

The carburetor is equipped with an idle system, the channel of which 9 has an outlet slot 10 in the wall of the mixing chamber 1, located in the area of the throttle 2 perpendicular to its axis.

The slit hole 10 (see Fig. 2.) has a length L of 4.5 mm and is designed so that when the throttle valve 2 is completely closed until it stops against the wall of the mixing chamber 1, the length l of the slot located above the closed throttle valve, equal to 3.25 mm, with a thickness of the throttle 2 equal to 1.0 mm Below the throttle valve 2 is a circular hole 11 designed to supply fuel at idle.

The carburetor works as follows.

At idle, throttle 2 is slightly ajar, and its position is determined by the adjusting screw (not shown) of the amount of mixture. Moreover, due to the low air flow in this mode, the vacuum in the diffuser 4 is not enough for the fuel to flow through the channels of the main metering system and the carburetor operates in idle mode. In this mode, the fuel from the float chamber 8 through the fuel nozzle 12 enters the emulsion well 7, from where the fuel passes through the idle system channel 9 through the idle system fuel nozzle 13 at the outlet of which the fuel is mixed with air entering through the idle system air nozzle 14 . Further, the air-fuel mixture passing through the channel 9 is additionally depleted due to air entering the channel 9 through the upper part of the slot 10 located above the throttle valve. At the same time, through the lower part of the gap under the throttle valve 2, a small part of the fuel-air mixture enters the throttle space. The main part of the fuel-air mixture from channel 9 enters the cavity of the quality adjusting screw 15, which controls the total amount of fuel at the minimum engine speed at idle, and then the air-fuel mixture enters the throttle space through a circular hole 11 in the wall of the mixing chamber 1.

With the further opening of the throttle valve 2 of the primary chamber (relative to the initial position at idle) in the low and medium engine load modes, a rarefaction zone forms under the throttle valve 2, while the upper part of the slot 10 located above the throttle valve starts to work as an air jet , and its lower part is like an emulsion jet. As you move the edge of the throttle 2 upwards, the lower part of the gap increases, falling into the high vacuum zone. In this case, the vacuum at the fuel idle nozzle 13 increases accordingly and the fuel consumption through it increases in proportion to the increase in the amount of air entering the throttle space. In this case, the fuel consumption through the slotted hole 10 increases, and through the round hole 11 idle stops, providing a smooth transition between idle and light loads.

Further opening of the throttle valve 2 leads to an increase in vacuum in the area of the outlet of the emulsion channel 6 of the spray gun 5 of the diffuser 4 of the main metering system, and when the damper reaches the position when the upper edge of the throttle valve 2 reaches the upper edge of the slot 10, this vacuum is sufficient to start the outflow fuel through the main metering system. The increase in fuel consumption through the slot 10 occurs until it is completely under the throttle 2. The subsequent opening of the throttle 2 leads to a gradual, until complete cessation, decrease in fuel consumption through the slot 10, which is compensated by an increase in fuel consumption through the main dosing system, which provides a smooth transition between the mode of small and medium loads.

At high loads and, accordingly, large opening angles of the throttle valve 2, the vacuum in the zone of the outlet of the emulsion channel 6 of the diffuser 5 of the diffuser 4 of the main metering system becomes larger than the vacuum in the mixing chamber of the idle outlet 11 and the slot 10. In this case, The so-called self-compensation phenomenon, in which there is a reverse movement of air from the main air path through the slotted hole 10 channel 9 of the idle system to the emulsion deck n 7 main dosing system. Thus, the slit hole 10 continues to participate in the mixture formation process, and the idle fuel nozzle 13 becomes an additional air nozzle of the main metering system, improving the composition of the air-fuel mixture.

Figure 3 and figure 4. presents the throttle characteristics of the carburetor at different lengths of the slotted hole in the mixing chamber and various positions of the slotted hole relative to the initial position of the throttle in the mixing chamber, where:

GT - basic throttle characteristic with a valid range;

GT (4; 0.78) - Throttle characteristic of the carburetor, L = 4 mm, l / L = 0.78;

GT (5; 0.78) - Throttle characteristic of the carburetor, L = 5 mm, l / L = 0.78;

GT (4; 0.62) - Throttle characteristic of the carburetor, L = 4 mm, l / L = 0.62;

GT (5; 0.62) - Throttle characteristic of the carburetor, L = 5 mm, l // L = 0.62.

When choosing the parameters of the slot hole in the mixing chamber L = 4 mm, l / L = 0.78, the throttle characteristic GT (4; 0.78) showed a decrease in fuel consumption over the entire range of the slot hole 10, which leads to a deterioration in vehicle driving performance starting and low speeds, a drop in engine power due to overpopulation of the mixture, a significant increase in mass emissions of unburned particles of hydrocarbons (see Fig. 3.).

When choosing the parameters of the slotted hole in the mixing chamber L = 5 mm, l / L = 0.78, the throttle characteristic GT (5; 0.78) showed a decrease in fuel consumption from the initial position of the throttle valve 2 until the main dosing system is switched on, after which there was an excess of fuel consumption by the throttle characteristic until the end of the operation of the slot 10, which leads to a deterioration in the ride quality of the car when starting and to an unacceptable increase in the content of carbon monoxide in the exhaust gases at an increased frequency x Lost travel. (See figure 3.).

When choosing the parameters of the slotted hole in the mixing chamber L = 4 mm, l / L = 0.62, the throttle characteristic GT (4; 0.62) showed an increase in fuel consumption from the initial position of the throttle valve 2 until the main dosing system is switched on, after which there was a decrease in fuel consumption until the end of the operation of the slit hole 10, which leads to a deterioration in the rideability of the car at low speeds (dips, pokes), an increase in fuel consumption, and an increase in mass emissions of carbon monoxide and hydrocarbons. (See figure 4.).

When choosing the parameters of the slit hole in the mixing chamber L = 5 mm, l / L = 0.62, the throttle characteristic GT (5; 0.62) showed an increase in fuel consumption over the entire range of operation of the slit hole 10, which leads to an increase in operational fuel consumption, mass emissions of carbon monoxide, an unacceptable increase in the content of carbon monoxide in the exhaust gases at an increased frequency of idling. (See figure 4.).

The experimental results confirmed that the manufacture of a carburetor with a slit outlet in the mixing chamber in accordance with this utility model provides improved interaction between the main dosing system and the idle system.

The application of the utility model allowed to improve the interaction of dosing systems of K-178 carburetors in transient engine operation, to reduce operating costs of fuel and mass emissions of harmful substances with engine exhaust when the car is moving in urban conditions.

List of literature

1. CARBURETTOR FOR THE INTERNAL COMBUSTION ENGINE.

Copyright certificate, SU 1275106 dated 12/07/86.

2. Orlov V.A., Losev V.E. Car carburetors. L., "Engineering", 1997

3. Solex carburetors. Service and repair. Illustrated Guide. M. LLC "Publishing House" Behind the Wheel ", 2005. (Series" On their own ").

Claims (3)

1. A carburetor for an internal combustion engine containing at least one mixing chamber with a throttle valve, a diffuser installed in the main air channel of the carburetor, having a spray gun in communication with the float chamber through the main metering system, and an idle system, the channel of which has a vertical outlet a slotted hole located in the wall of the mixing chamber, characterized in that the slotted hole in the wall of the channel of the mixing chamber is made from 4 to 5 mm long and is positioned in this way m, that with a fully closed throttle valve with a thickness of 0.8 to 1.2 mm until the edge stops against the wall of the mixing chamber, the throttle valve divides the exit slot in the wall of the mixing chamber into two unequal parts located above and below the valve, with the ratio between the length of the part of the slit located above the fully closed throttle to the entire length of the slit, which is in the range of 0.62-0.78. 2. A carburetor for an internal combustion engine according to claim 1, characterized in that the lower edge of the slotted hole is at a distance of not more than 0.5 mm from the lower edge of the fully closed throttle. 3. The carburetor for the internal combustion engine of claim 1, characterized in that the installation angle of the fully closed throttle valve relative to the plane perpendicular to the axis of the main air path is 7-13 degrees.