Carburetors may not have been touched by many people, especially many modern car owners, but they know very little about this kind of thing. In fact, carburetor is a very common thing on motorcycles, on four-wheeled cars. At present, it is relatively rare. In some previous motor vehicles, there will also be the emergence and use of carburetor. It has developed into the current state. The carburetor is mainly used for motorcycles. The carburetor is actually a pipe. The role of the fuel is to atomize the fuel and mix it with the air to improve the efficiency of the fuel, and to form a mixture, so that the internal combustion engine of the engine can work better, so the structure of the carburetor is also Extremely simple, not too complicated, but there are still some counterfeit products in the carburetor. This article will introduce you to the structure of the carburetor in detail, and let everyone know how to distinguish the carburetor.
First, what is the carburetor?A device for forming a combustible mixture of gasoline, kerosene, and the like with a gas in a spark-ignition internal combustion engine (such as a gasoline engine), which is also called a vaporizer. The function of the carburetor is: by the driver stepping on the position of the accelerator pedal, according to the requirements of different working conditions of the internal combustion engine, providing a corresponding amount of fuel; atomizing the fuel and uniformly mixing with the air to obtain a combustible mixture of a certain composition, so as to be good Combustion; ensure a smooth transition between the various operating conditions of the internal combustion engine.
Second, the structure of the carburetor
Most motorcycle carburetor passages are controlled by the damper position rather than the engine speed. There are five main adjustment systems in the motorcycle carburetor. These adjustment systems affect each other. They are idle speed passages, idle speed orifices, main nozzles and oil needles, main orifices, and choke passages. They are described below.
1, the choke system
The choke system is primarily used for cold start and will inject more fuel into the cylinder to compensate for the fuel that is condensing on the cylinder wall. Once the engine is warming, the choke must be closed.
2, the main volume
The main orifice controls the flow of fuel from 3/4 throttle opening to full throttle opening.
3. Oil needle and main nozzle
The oil needle and main nozzle affect the vaporization from the 1/4 to 3/4 throttle opening. The oil needle is a long tapered rod that controls how much fuel can be drawn into the carburetor throat. The top of the oil needle has a plurality of grooves, and the position of the clamp on the needle can be adjusted up and down, and the mixed gas becomes thick and thin. The clamp moves up and becomes thinner, and moves down and becomes thicker.
4, the speed of the hole
The idle speed hole is a component that supplies most of the fuel when the throttle opening is low. It has a small hole in the fuel flow. Both the idle air screw and the idle speed hole affect the vaporization from the idle speed to about 1/4 of the throttle opening.
5, idle speed channel
The idle channel has two adjustable sections. Throttle air screw and idle speed hole. The air screw is usually on the back or front of the carburetor.
On the back side, it adjusts how much air enters the throttle system. At this point, the screwing of the air screw will reduce the amount of air and enrich the mixture; and unscrewing will open more channels into the air to make the mixture thinner. If it is in front, it is to regulate the supply of fuel. The swirling mixture will become thinner and the mixture will become thicker.
Third, the working principle of the carburetor
The carburetor is actually a tube with an adjustable plate called a throttle plate in the middle of the tube. The atmospheric pressure will spread from high pressure to low pressure. When the piston of the two-stroke engine is at top dead center (or the piston of the four-stroke engine is at the bottom dead center), a low pressure is formed under the piston in the crankcase (above the piston of the four-stroke engine). At the same time, this low pressure will also cause low pressure in the carburetor. Because the pressure outside the engine and carburetor is relatively high, the air will rush into the oil and enter the engine until the pressure equalizes. The air flowing through the carburetor will drive the fuel, which in turn will mix with the air.
Air enters the carburetor through the air filter. Based on the fact that the intake resistance cannot be too large and other factors, the filter device should not be too dense, so some tiny impurities in the air will still enter the carburetor through the air filter. If the quality of the filter is defective, it will have a more serious impact.
The components of the carburetor oil passage and air passage, such as the main orifice, the idle orifice, the main air orifice, the idle air orifice, the main foam pipe, etc., have small inner diameter holes (inner diameter is 0.3). Between ~1.5mm), gasoline impurities, colloids and impurities in the air entering the carburetor will often change or block these pore sizes, resulting in carburetor air passages and oil passages, making the carburetor available. Changes in oil properties and even carburetor performance failures.
The carburetor is a mechanical device that mixes a certain proportion of gasoline with air under the vacuum generated by the operation of the engine. The carburetor is a sophisticated mechanical device that uses the kinetic energy of the suction air stream to atomize the gasoline. Its important role in the engine can be called the "heart" of the engine. In order to make the blended mixture more uniform, the carburetor also has the effect of atomizing the fuel for normal operation of the machine. Since the vast majority of imported carburetor in the domestic market is produced in Japan, most of the domestically produced carburetor is also a cottage product that imitates Nissan carburetor. Therefore, this paper mainly introduces the identification method for Nissan carburetor. .
1, pay attention to distinguish the meaning of English
There is a type of fake imported carburetor that makes a fuss in English. For example, some kind of carburetor, "japan" is in the eye, but there is "design in" (the design), which only shows that this carburetor is imitation of Japan, not made in Japan. However, car dealers deceive car buyers do not know English, and they are eager to import goods. For the carburetor with "design in japan", the process is not bad. Some car buyers see the word "in japan", which is believed to be made in Japan. According to the author's understanding, several car manufacturers in China have assembled this carburetor at the time of motorcycle delivery, and buyers must distinguish it.
By the way, if the Japanese original carburetor has the word "made in japan", the assembly is only "japan". For domestic motorcycles with a displacement of 125ml or less, most of the imported carburetor is assembled. Although it is assembled, if it is assembled by a large factory, car buyers can rest assured to buy.
The price of a genuine imported carburetor and counterfeit goods is very different. More importantly, true and false are related to the performance of motorcycles, engine life and fuel consumption. Those who want to buy a car must be treated with caution.
2, carburetor process
Really imported carburetor, the name of the country name, the name of the factory, the logo, the code and so on seem to be exquisitely crafted, at a glance, especially the coding is clearer than the fake. And some fake imported carburetor codes are often unclear and not feasible.
At present, this kind of fake import goods with poor coding process is popular in the market. Unscrupulous dealers replace the imported carburetor with the counterfeit goods and punish the car buyers. Therefore, the first time buyers must be cautious, if conditions permit, you may wish to open a motorcycle equipped with imported carburetor to the point of purchase to compare.
The Japanese original carburetor is the word "MADE IN JAPAN". The imported carburetor used in domestic Mitsubishi Jeep 4G63/64/54 is imported from Japan. There is no domestic carburetor. If it is purchased in Guangzhou or a regular merchant specializing in imported parts from Japan, you can buy it with confidence. There is a fundamental difference between it and fakes. Original imported carburetor and fake goods prices are very different, more importantly, true and false are related to your car performance, engine life, fuel consumption, etc., so the purchase of pure imported carburetor is particularly important.