What Is the Difference Between Supercharged and Turbocharged?

by MOU YONG HONG on December 01, 2021

Both turbocharging and supercharging use forced air to increase the power of the engine, but the working principles of the two are different, and the actual effect is also different.

The turbocharger is called Turbo Supercharger, the mechanical supercharger is called Mechanical Supercharger, and later gradually called Turbocharger and Supercharger, abbreviated "T" and "S".

"T" and "S" are the first difference between turbocharging and supercharging.

Simply put, a supercharger directly uses the power of the engine to drive the supercharger; while turbocharging uses the airflow when the engine discharges exhaust gas to drive the compressor, so turbocharging is often called exhaust gas turbocharger. Pressure.

The difference in drive form is the second difference between turbocharging and supercharging.

The supercharger is more direct in the design concept, so it is much earlier than the turbocharger. The earliest supercharging system appeared in the Grand Prix racing car in the 1920s, and turbocharging did not begin to emerge until the 1970s. Saab in Northern Europe and Sweden was the first company to apply turbochargers to Car manufacturers on car products.

The huge difference in the birth period is the third difference between turbocharging and supercharging.

Because turbocharging uses the exhaust gas of the engine to push the turbine, when the amount of exhaust gas from the engine is small, the turbine rotates slowly, and the effect of the supercharger is not obvious. The method is often referred to as "turbo lag". The supercharger is directly connected to the output end of the engine through a belt. The supercharger starts at the moment the engine rotates. It has the linearity of natural aspiration and the response is also fast.

The difference in power output is the fourth difference between turbocharging and supercharging.

Since the power source of supercharging is the power output by the engine, this will undoubtedly bring a burden to the engine, so small-displacement engines generally do not use supercharging; now turbocharging is mostly installed in small-displacement engines, In order to achieve the purpose of outputting large power with small displacement, it should deal with the taxes and fees levied by various countries according to the row; even some medium-sized cars have used small-displacement turbocharged engines. Of course, high-displacement performance cars will also use turbos or even multi-turbos, this is for power needs.

The difference in the scope of use is the fifth difference between turbocharging and supercharging.

Because of the difference in principle, supercharging and turbocharging are not irreconcilable technologies. They can even be installed on the same engine, such as Volkswagen’s 1.4TSI dual-supercharged engine (but the domestically produced 1.4TSI engine has been canceled. Supercharged and stratified combustion, only turbocharging and direct injection are retained). In this way, the advantages of the two can be combined to solve the problem of turbo lag and the problem of supercharging efficiency.

There is no conflict in nature, which is another feature of turbocharging and supercharging.

Both turbocharging and supercharging increase the air density of the cylinder, so as to burn more fuel without increasing the displacement, so that the horsepower is increased, but the operating principle of the two superchargers is different, and the turbine depends on The combustion exhaust gas drives the operation, and the supercharger relies on the rotation of the engine to drive the operation. The speed of the turbofan of the supercharger is the same as the engine speed. Below I will analyze the differences between the two and their advantages and disadvantages:

Turbocharger: (as shown in the picture) a turbocharger is actually an air compressor, which increases the intake air volume by compressing air. It uses the inertial impulse of exhaust gas discharged from the engine to push the turbine in the turbine chamber, and the turbine drives the coaxial impeller. The impeller presses the air sent from the air filter pipe to pressurize it into the cylinder. When the engine speed increases, the exhaust gas discharge speed, and the turbine speed also increase simultaneously, and the impeller compresses more air into the cylinder. The increase in air pressure and density can burn more fuel, increase the amount of fuel, and adjust the engine's speed accordingly. Speed, you can increase the output power of the engine.

Supercharger: (as shown in the picture) the rotor of the supercharger is connected to the crankshaft of the engine, which means that the supercharger needs the engine speed to drive it. The driving force of the compressor comes from the crankshaft of the engine. Generally, a belt is used to connect the crankshaft pulley to indirectly drive the supercharger with the torque of the crankshaft to achieve the purpose of supercharging. In addition to supercharging at low speeds, the supercharged power output is also proportional to the crankshaft speed. That is, as the speed of a supercharged engine increases, the output of the supercharger will increase accordingly. The operating feeling of a supercharged engine is very similar to that of naturally aspirated, but it can have greater horsepower and torque.

Pros and cons

Turbocharging: Turbocharging uses the exhaust gas produced by the engine to drive the turbofan in the exhaust pipe to drive the turbofan in the intake pipe to rotate, thereby performing indirect supercharging without consuming engine power. The turbocharger has a very high speed, and the increased pressure is several times higher than that of a supercharger. However, due to the inertia of the turbofan, the intermediate bearing also has considerable resistance. When the exhaust gas suddenly increases, the speed of the turbofan will not increase at the same time, which is also turbo lag. (At present, due to the popularity of small turbines, the intervention speed is low, so the problem of hysteresis is basically solved) Because the working environment is at an extremely high temperature, the vitality of the turbine is weakened to a certain extent.

Supercharger: Supercharger uses the power of the engine itself to drive a compressor for supercharging. The supercharger consumes the power of the engine. Its speed changes with the engine speed, and there is no supercharging lag. The effect is excellent when the engine is running at low speed, but it is limited by the engine speed, and the engine will increase at high speed. Underpressure. The supercharger is more linear because the rotor speed is at the same frequency as the engine, but the supercharger is driven by the power of the engine itself, so it requires a higher displacement. This also explains that most supercharged engines also have a minimum of 2.5 The reason for the above displacement is that the power of the engine itself will be weakened if the displacement is not enough.


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