SU848724A1 - Carburettor for i.c.engine - Google Patents

Description

one

FIELD OF THE INVENTION The invention relates to engine-building, in particular to carburetors.

Carburetors are known for stationary internal combustion engines operating with automatic speed control. These carburetors contain a housing with a device for maintaining a constant fuel level, for example with a float chamber. In the case there is a fuel-air path with large and small diffusers, air and throttle. Selective damper, main metering system of emulsion or non-emulsion type with fuel inlet channels, idle system with fuel and air jets and emulsion channel, communicated with the air-fuel duct by a transition hole in the upper edge of the throttle valve and an adjustable hole in the throttling space. The main metering systems are connected to the float chamber by parallel or serial LlJ methods.

The disadvantage of such carburetors is that the idle system

stroke and main metering system as load increases. At the time of entry into operation of the main metering system, there is a significant unevenness in the fuel supply over time, which causes fluctuations in the composition of the mixture from cycle to cycle and a relatively increased unevenness in the number of engine revolutions.

10 In addition, the formation of optimal. Characteristics of the composition of the mixture according to the load mode of operation under such implementation of fuel-dosing systems require a transition hole in the system of idling, which ensures a smooth transition from idling to the load mode of operation. In order to obtain the required production stability of the characteristics, the transition hole must be performed with great accuracy both in absolute dimensions and in coordinate with respect to the throttle valve edge, the processing frequency of the input and output edges, which provides technologically complex operations. In addition, the degree of atomization of the fuel in the main metering system, especially at low air flow rates, the corresponding moments

When it enters its operation, it is insufficient, which is caused by the presence of a significantly larger diameter than the fuel jet of the jet, the emulsion in the atomizer splits into liquid and gaseous phases, as a result of which the maximum size of fuel droplets at the outlet of the atomizer increases, is observed runoff of fuel along the inner surface of the small diffuser with a periodic disruption of droplets from its lower edge.

Closest to the present are carburetors, in which the simultaneous entry of the main metering system and the idling system into operation is ensured, which allows the idling system to be performed without a vias 2.

However, the advantages of the carburetor are achieved by using a three-diffuser system and adjusting the fuel delivery characteristics in the main metering system with a precision profile needle. This significantly complicates the carburetor design.

The aim of the invention is to improve the mixture formation by increasing the uniformity of fuel supply to the air stream while simplifying the design.

This goal is achieved by the fact that the main dosing system is single-loop and is connected to the float chamber parallel to the idle system, and in the central part of the small diffuser there is a jumper with a fuel feed channel, at the end of which a fuel nozzle is installed. The exit edge of the nozzle protrudes beyond the surface of the web from the throttle side.

FIG. 1 shows a schematic diagram of a carburetor; in fig. 2 is a structural diagram of a small diffuser with a main fuel jet and a stopper installed in it / in FIG. 3 - small diffuser, plan view

In the carburetor body 1 having a float chamber 2, the fuel-air path 3 is installed, in which a large diffuser 4 and a small diffuser 5 are installed, as well as an air damper b and throttle 7 The main metering system includes a fuel inlet channel B and a main fuel jet 9 , installed at the end of the fuel feed channel, the output section of which is located in the jumper 10 of the central part of the small diffuser. The main fuel jet is equipped with a sharp exit edge 11, which is assembled on the surface, with oversides from the side: oi barrier

The fuel supply duct is connected to the float chamber and is provided with a plug 12 with a gasket 13 on the side of the small diffuser. The length of the stopper is determined by the distance from the bearing surface of the gasket to the horizontal section of the fuel duct. The idling system is connected directly to the float chamber parallel to the main dosirkudey system and contains a fuel intake channel 14, a fuel jet 15, an air jet 16 and an emulsion duct 17 connected to the air fuel path with only one outlet 18, extending into the throttle space and equipped with an adjusting screw 19 .

The carburetor works as follows.

Claims (2)

The engine is started with the position of the air damper 6 closed. In all modes, including low idle speeds, both the idle system of the 5th stroke and the main metering system work simultaneously. This early entry of the main metering system is achieved by the following measures: elimination of emulsification in it, removal of the fuel jet 9 to the final section of the hydraulic path, use of a parallel method for switching on the idling system and some decrease in the piezometric height of the main fuel jet 2. The latter is quite acceptable for a carburettor stationary engine, where there is no inertial load on the fuel in the float chamber. The location of the main fuel jet 9 at the exit of the fuel path and its execution with a sharp output edge 11 allows for a continuous discharge of fuel into the air stream, i.e. to ensure uniformity of its distribution along the length of the air charge. When the fuel leaves the main fuel jet 9, the jet is removed under the action of capillary forces, and its diameter in the initial segment before disintegration into separate droplets turns out to be significantly smaller than the diameter of the main fuel jet jet 9. Therefore, in the supra-throttling space of the fuel-air path 3 the stroke is finely sawn. Since both dosing systems operate simultaneously, the carburettor does not require the use of a vias. In this case, it is possible to significantly increase the diameter of the air jet 16 and reduce the requirements for the accuracy of its production. The adjustment of the composition of the mixture with the screw 19 is made only at low idle speeds. In the future, it depends only on the dilution over the carburetum, i.e. with the opening of the throttle valve 7 and the increase in load, the fuel consumption through the idling system is reduced, and through the main dosing system increases. The restriction imposed on the length of the plug 12 excludes the possibility of the formation of a vapor bubble in the fuel feed channel. The most appropriate is the implementation of the design in carburetors with a falling mixture flow, where the direction of the gravitational force helps to maintain the jet nature of the outflow. fuel from the main fuel jet 9, however, it is possible to perform such a scheme in carburetors with a horizontal mixture flow. The test data of the carburettor showed that it provides a close relationship to the adjustment limits on the composition of the mixture, the required slope of the regulatory characteristics, and an improvement in the parameters of the transient process during loading. In addition, it provides a reduction of the specific estimated fuel consumption in comparison with the existing structures by 7–11%. The reduction in bone production is achieved by reducing the number of calibrated dosing elements and the exception of the vias. A carburettor for an internal combustion engine, comprising a housing housing an air path with a large and a small diffuser, throttle and air dampers, a float chamber, a main metering system with a fuel inlet channel, an idling system with a fuel and air jets and an emulsion channel communicated with the fuel-air duct by a single hole located under the throttle valve, characterized in that, in order to improve the mixture formation by increasing the uniformity and the fuel supply to the air flow, the main metering system is made single-jet and connected to the float chamber parallel to the idling system, in the central part of the small diffuser a jumper is installed with a stop-supply channel connected to the main metering system, and a fuel jet is installed at the end of the latter, the output which stands for the surface of the jumper with. side throttle. Sources of information taken into consideration in the examination. 1. Gribanov V.I. and Orlov V.A. Carburetors of internal combustion engines. L., Mechanical Engineering, 1967, p. 191. 2. German patent number 843762, l. 46 from 15/02, 1949.