How does a turbocharger work in a car?



Also, how is it different from a supercharger?

In: Engineering

Both force extra air into the engine. A turbo uses exhaust gas to spin a turbine which in turn spins another turbine that sucks in air. More air means you can add more fuel and more fuel means MORE POWER. superchargers do the same thing but instead of using exhaust gas they have a pulley hooked up to the engine that spins a turbine/roots style corkscrew to pull in more air.

Both are essentially a fan that forces air inside the engine, the more air you can fit in an engine the more power you can make

The only difference between the two is how the fan is powered, in a turbocharger it’s powered by a turbine (which is where you get the turbo part) that runs off the exhaust, a supercharger is spun directly by the engine

A turbo and a supercharger force more air into your engine, allowing more fuel in too (you get the same fuel:air ratio, just at a higher pressure), thus increasing the power you can get out of a set volume cylinder.

A supercharger runs off a physical belt attached to the engine, whereas a turbo is powered by exhaust gasses passing through a turbine. Because of this, a supercharger essentially saps some energy from your engine because it has to move the belt, and a turbo will experience a ‘lag’ because it takes time for the exhaust gases to spin the turbine faster as you put your foot down.

Both turbocharger and supercharger are trying to compress air to fit more in the cylinders so you can spray more gas in and get more power out of the same volume of engine.

Supercharges are fed by a belt on the engine so they work at full capacity even at idle. Turbochargers are fed by the exhaust so they hurt a bit at idle and only really help at high RPMs

A standard [turbocharger]( is two axial flow turbines bolted together. For the hot side on the left, the hot exhaust is forced in around the edge of the fan which forces the fan to spin and the gas escapes through the middle on the axis(axial fan afterall) that the fan is spinning around. This fan is on the same shaft as one on the air intake that works the exact opposite by taking in air in the center and flinging it out to the sides. Now when the piston opens the intake valve the air rushes in because its at pressure instead of being pulled in by the piston alone.

Superchargers come in a lot more varieties. Screw superchargers are basically two intertwined screws with a tiny gap between them. The threads on the screws grab the air and force it down between them into a higher pressure area.

Superchargers are nice in that they give you boost at low revs which is good for performance, but also eat up a good chunk of horsepower which hurts fuel economy.

Turbochargers extract wasted energy from the exhaust and use that instead of useful energy the pistons extracted so they can be used to improve the fuel economy of engines and let you use a much smaller engine for the same power/torque (see Ford EcoBoosts). Their main downside is not working across the power band but that has been resolved with a lot of modern designs that can move parts on the fly to change the turbo between a low resistance mode for efficient cruising and a high boost mode for high boost when needed

Why not just look it up on YouTube or something? I’m sure you can get a better picture of how these things work with a video.

A “charge” in an internal combustion engine is the mix of air and fuel that’s placed into the cylinder. The more charge you have, the more energy you can produce.

If the engine is “naturally aspirated” the only thing drawing in air is the movement of the cylinder downward. The “charge” is whatever air flows into the cylinder due to the slightly lower pressure of the cylinder with respect to the atmosphere. For such engines, the “charge” can be around 0.6-0.7 atmospheres at idle, and >0.9 atmospheres when running at full power. But it’s never going to be greater than (or even equal to) the pressure of the air outside the car.

Supercharging is the act of putting more charge than that into an engine. This is done by using an air compressor to suck up and squeeze air into the engine, making the pressure in the cylinders much more than the pressure outside. More pressure means more mass of air, and if you add more fuel to that mass, you get more power per stroke.

In the first superchargers, the energy to run that air compressor was originally from a belt that ran off the engine crankshaft. This causes the engine to work harder, but the extra power it can produce from having more air and fuel in the cylinder more than makes up for it. Superchargers using belts were invented really early into the development of the automobile, so they were around for a long time, and it became common vernacular that a “supercharger” was specifically a supercharger that got power via a belt on the crankshaft, because that was the only type of supercharger there was.

Starting in the 1960s, a completely new type of automotive supercharger became popular. Instead of using a belt, the power for the compressor comes from a turbine that the exhaust gas blows over. This turbo-supercharger had some benefits and drawbacks. It was generally more efficient and had fewer moving parts, but it was also subject to extreme temperatures and chemicals from the exhaust.

After a while, the turbo-supercharger was just called a turbocharger. Meanwhile, the belt-driven supercharger was never called a “belt-supercharger.” So belt-driven superchargers are called “superchargers” and exhaust-driven superchargers called “turbochargers.”

There are benefits and drawbacks to both types. Generally, turbochargers get less practical the larger the engine, so you’ll usually see turbochargers in passenger cars and superchargers in heavy duty trucks.

Both are pumps. They force more air into the engine by increasing air pressure to the intake.

Turbochargers are turbine driven centrifugal pumps driven by engine exhaust gasses.

Superchargers are are engine driven pumps. Both positive displacement screw/vane type and centrifugal types exist.