Honest Auto Tech

Hello This is Bhushan. I will try to give you AutoGyan (Automotive information)/Honest Automobile Reviews.

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Thursday, January 3, 2019

Automobile Turbochargers

Hello Everyone, Welcome to new Article
Everyone loves to drive car and often we dream to extract more and more juice from our Beast. Some times we do some after market modifications and some ECU remapping but it is not sufficient.
Since the invention of the internal com­bustion engine, automotive engineers, speed freakies and racecar drivers have been searching for ways to boost its power. ­One way to add power is to build a bigger engine. But bigger engines, which weigh more and cost more to build and maintain, are not always better option, above lines were read in my last blog.

In this Article we will read about Turbochargers

When people talk about race cars or high-performance sports cars, the topic of turbochargers usually comes up. Turbochargers also equipped on large diesel engines. Turbocharger can significantly boost an engine's brake horsepower without increasing in its weight, which is the benefit that makes turbocharger so much popular!

We'll see how a turbocharger increases the power output of an engine while working in extreme operating conditions.Turbochargers are a type of forced induction system. (Conventional engines are running on natural induction or circulation). They compress the air goiing into the engine The advantage of compressing the air is that it lets the engine squeeze n compress more air into a cylinder, and more air means that more fuel can be added. Therefore, you get more power from each explosion in each cylinder. A turbocharged engine produces more power overall than the same engine without the charging. This can significantly improve the power-to-weight ratio for the engine In order to achieve this boost, the turbocharger uses the exhaust flow from the engine to spin a turbine, which in turn spins an air pump. The turbine in the turbocharger spins at speeds of up to 150,000 rotations per minute (rpm) that's about 30 times faster than most car engines can go. And since it is attached to the exhaust, the temperatures in the turbine are also very high.
One of the surest ways to get more power out of an engine is to increase the amount of air and fuel that it can burn. One way to do this is to add cylinders or make the current cylinders bigger. Sometimes these changes may not be feasible -- a turbo can be a simpler, more compact way to add power, especially for an aftermarket accessory.

Turbochargers allow an engine to burn more fuel and air into the existing cylinders. Since normal atmospheric pressure is 14.7 psi at sea level, you can see that you are getting about 50 percent more air into the engine. Therefore, you would expect to get 50 percent more power. It's not perfectly efficient, so you might get a 30- to 40-percent improvement instead.

One cause of the inefficiency comes from the fact that the power to spin the turbine is not free. Having a turbine in the exhaust flow increases the restriction in the exhaust. This means that on the exhaust stroke, the engine has to push against a higher back-pressure. This subtracts a little bit of power from the cylinders that are firing at the same time.­
The turbocharger is bolted to the exhaust manifold of the engine. The exhaust from the cylinders spins the turbine, which works like a gas turbine engine. The turbine is connected by a shaft to the compressor, which is located between the air filter and the intake manifold. The compressor pressurizes the air going into the pistons.

The exhaust from the cylinders passes through the turbine blades, causing the turbine to spin. The more exhaust that goes through the blades, the faster they spin.
On the other end of the shaft that the turbine is attached to, the compressor pumps air into the cylinders. The compressor is a type of centrifugal pump -- it draws air in at the center of its blades and flings it outward as it spins.
There are many tradeo ffs involved in designing a turbocharger for an engine. In the next section, we'll look at some of these compromises and see how they affect performance.
A turbocharger also helps at high altitudes, where the air is less dense. Normal engines will experience reduced power at high altitudes because for each stroke of the piston, the engine will get a smaller mass of air. A turbocharged engine may also have reduced power, but the reduction will be less dramatic because the thinner air is easier for the turbocharger to pump.

Older cars with carburetors automatically increase the fuel rate to match the increased airflow going into the cylinders. Modern cars with fuel injection will also do this to a point. The fuel-injection system relies on oxygen sensors in the exhaust to determine if the air-to-fuel ratio is correct, so these systems will automatically increase the fuel flow if a turbo is added.

If a turbocharger with too much boost is added to a fuel-injected car, the system may not provide enough fuel -- either the software programmed into the controller will not allow it, or the pump and injectors are not capable of supplying it. In this case, other modifications will have to be made to get the maximum benefit from the turbocharger.

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