Common superchargers for the most popular automobi

2022-08-09
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Common superchargers for automobile refitting

Abstract: the double screw supercharger, also known as roots blower, is very similar to the Roux supercharger. The double screw supercharger sucks air through two meshing flange rotors similar to a group of turbine drive, and the air in the booster is also sucked through the rotor flange

Hello! hello everyone! Last week, we learned and understood the advantages and disadvantages of supercharging, but many people responded that superchargers also have many classifications. Due to different functions and principles, the advantages and disadvantages of supercharging cannot be generalized, so we will focus on the classification of superchargers in this issue. There have been many types of superchargers,

including roots, double screw and centrifugal. The main difference between them is the way in which air is drawn into the engine intake manifold. Lu and double screw superchargers use different types of meshing flanges, while centrifugal superchargers use the rotation of the impeller to suck in air. Let's have a detailed look

roots supercharger

roots supercharger is the first design in the supercharger family. It was invented and patented by philander and Francis roots as early as 1860. Its first purpose is to ventilate the internal channel of the mine. After the invention of the internal combustion engine, gottleib Daimler first installed the Roux supercharger in the automobile engine in 1900

▲ working principle of Lu's supercharger

there are two flange rotors in Lu's compressor, which mesh with each other. When the driving shaft engages with the flange of the driven shaft and rotates, a vacuum or negative pressure is generated between the flanges, so that the air will be sucked in and then transmitted between the air inlet and the exhaust port of the supercharger. A large amount of air will enter the intake manifold and accumulate to produce positive pressure. However, the supercharger of this design does not inhale air continuously, but intermittently (although the intermittence is very short, it cannot be ignored). Moreover, the rotor flange body is bulky, needs to consume more crankshaft torque, and the efficiency is not high. Moreover, the compressed air of this kind of supercharger will emit a roar when it is discharged from the compressor. Generally, noise reduction devices need to be installed to reduce the noise

▲ Eaton Lu's supercharger on Saturn's 2006 ion under GM but with the same performance

Lu's supercharger is usually large and installed on the top of the engine. Because they can be installed outside the engine cover, they are very popular in high-power cars. However, it is the most efficient supercharger for two reasons: on the one hand, it is heavy, which increases the weight of the car; on the other hand, it can only inhale air intermittently, but not smoothly and continuously

double screw supercharger

double screw supercharger, also known as roots blower, is very similar to Roux supercharger. The double screw supercharger sucks air through two meshing flange rotors similar to a group of turbine drive, and the air in the supercharger is also sucked together through the rotor flange. Different from Lu's supercharger, the double screw supercharger will continuously compress the air in the rotor housing because of the low recycling rate of waste plastics in China at present, rather than intermittently sucking air like Lu's supercharger. The reason is that these rotors have a certain taper, which means that as the air flows from the supercharger inlet to the exhaust port, the airway will become smaller. With the contraction of the airway, the air is pressed into a smaller space, so that the compression of the air can be carried out continuously, which not only improves the compression efficiency of the supercharger, but also makes the supercharger unnecessary to be made very large

▲ the working principle of the double screw supercharger can be selected according to your own requirements.

due to the shape of the rotor flange, precision machining is required in the manufacturing process, which increases the manufacturing cost of this supercharger. Like Lu's supercharger, the double screw supercharger is generally installed above the engine, and some will choose to be installed on the side of the engine. Because its working principle is very similar to that of the Lu supercharger, the compressed air discharged from the exhaust port will emit a roar like the Lu supercharger. Generally, noise reduction devices must be used to eliminate these sounds

centrifugal supercharger

centrifugal supercharger draws air into the narrow compressor shell at high speed by using the rotation of the impeller. The shape of its impeller is very similar to that of the rotor of the turbocharger compressor. Its speed can reach 50000-60000 revolutions per minute through the amplification of the input shaft transmission. The air is sucked in at the impeller hub, and the centrifugal force generated by the rotation of the impeller will cause the air to diffuse outward. This air will make the impeller in a high-speed low-pressure state. The diffuser is a set of fixed blades surrounding the impeller, which will convert high-speed and low-pressure air into low-speed and high-pressure air. When air molecules touch these blades, they slow down, reducing the air flow speed and increasing pressure. Like any centrifugal supercharger, it provides a small range of supercharging to assist the engine in working at low engine speed, and the air will bypass when the engine decelerates. One thing is the same as Lu's and twin-screw, that is, it can provide effective supercharging value at any working speed of the engine. However, gasoline engines require fuel and oxygen to be compressed into a mixture and burned in a relatively small proportion, so it has become a hot spot for many people to pay attention to in the working state of low speed for 20 years. In fact, centrifugal superchargers can not provide enough oxygen to provide combustion in the low speed range as roux and double screw superchargers, so centrifugal superchargers are considered to be used in large displacement engines, And in the start-up phase, there is no need to match the engine with too much forced air intake, which can also avoid the tire slipping in the engine start-up phase

▲ working principle of centrifugal supercharger

▲ centrifugal turbo supercharger in guangben Odyssey engine compartment

the supercharging efficiency of centrifugal supercharger is the highest of the above three superchargers. At the same time, the temperature of the air after supercharging is generally higher than the first two. It is often necessary to add an intercooler to reduce the temperature of compressed air. Because of its small size and light weight, this supercharger can be installed in front of the engine rather than on the top. Like other superchargers, it will also produce a distinctive roar when working. If necessary, noise reduction devices should also be installed. Because this supercharger is highly similar to the turbocharger, many people will think it is a turbocharger. But in terms of the driving mode of the compressor, it is a supercharger to the letter

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