The turbo is a great invention that has revolutionized the automobile since its inception. Currently 90% of current vehicles equip it, and thanks to it they can be built more powerful and much more efficient motors.
How does a turbo work?
Basically, a turbo uses the passage of exhaust gases to drive a turbine. This is connected by a shaft to a compressor that takes air at atmospheric pressure and compresses it so that it fits more into the combustion chambers. To the increase the amount of fresh air entering the cylinders, more fuel can be injected and thus increase performance in less space.
If this were not done, in order to burn the same amount of fuel with air at atmospheric pressure, larger combustion chambers would have to be used. That is, an engine with more displacement.
The Turbo works up to a certain pressure, expressed in bars, once it exceeds said pressure, it is released by means of a discharge valve, so as not to create an overpressure that could damage the engine.
This is one of the main reasons why the operating speed of a turbo it is usually at low revs and medium speed, not allowing the turbo to act when the engine turns at high revolutions. In fact, many turbocharged gasoline engines usually give their maximum power at around 5.000 or 6.000 rpm, while naturally aspirated engines can safely reach up to 7.000 rpm and some models even 8.000 or 9.000 rpm.
What is the turbo for?
In addition to increasing performance, the turbo can also be used to reducir fuel consumption. This is achieved by placing a turbo in smaller engines to get more performance out of them than a larger naturally aspirated engine. Because they are smaller, they are lighter and have less friction, so there is less performance loss through these routes.
Today, we can find many small displacement engines but with the performance of larger engines. For example, we can talk about the VAG Group's TSI engines or the PSA and BMW Group's THPs.
Advantages of the turbo
Higher performance
However, like many other things, the turbo has a number of advantages and disadvantages. As advantages we can point out those that we have already mentioned about the performance improvement. But not only performance in terms of maximum power, but also in terms of torque delivery. A turbo engine has more thrust at low or medium speeds thanks to the fact that it reaches its maximum torque much sooner than an atmospheric one.
Why does a turbo engine push from lower rpm?
You won't find the answer in theoretical operation of a combustion engine. What not everyone knows is that a naturally aspirated engine gets most of the air into the cylinders when the piston is already going up, not when the piston is sucking it in as it goes down.
This is due to the inertia generated in the air flow when it is sucked in, which tends to continue going in even though the piston is already going up. However, this only occurs to a significant extent when the motor is running at high speed. Hence, a naturally aspirated engine achieves the most efficient explosions at high revolutions. That is, its maximum torque.
in a turbocharged engine, this is not necessary, because air is forced in in the combustion chambers.
Consumption reduction
As we have mentioned before, the turbo can be used to reduce the consumption of a vehicle at the cost of reducing the size of its engine and maintaining power thanks to the turbo.
This is so due to lower weight of the engine and its components, which allow it to be moved with less power loss. In addition to the fact that this smaller size of the cylinders and other parts also translates into less friction, resulting in lower consumption.
Less emissions?
The reduction in consumption is directly related to fewer emissions. Nevertheless, this is not entirely true, as has been shown by removing the downsizing on some models. For example, the passage of 1.4 TSI engines to 1.5 TSI or the suppression of some 1.6 TDI engines in favor of 2.0 TDI.
An example of increased emissions caused by engines that are too small is the excess heat in the combustion chambers. Being smaller, heat dissipation is less and this excess heat generates more emissions of nitrogen oxides (NOx). Which are especially harmful to health.
Disadvantages of the turbo
turbo lag
As for the disadvantages, one of them is lag. That is, the delay that occurs from when we step on the accelerator until we notice that the car starts to spin up. In this period, time is lost that, depending on the situation, can make us eternal.
Today, this problem has been solved thanks to the variable geometry turbo and also to electronic pressure control of the turbo. Although these systems only reduce lag instead of eliminating it and are really effective in sporty and expensive models.
Requires more resistance
Another drawback when mounting a turbo is the engine design of our car. The engine requires a specific design to be damaged by the high pressures at which a turbo works. Although this no longer has to be considered an inconvenience since the generalization of these engines has normalized the creation of engine blocks able to withstand more pressure.
Less reliability?
Formerly, reliability was the Achilles heel of a turbo. The temperature that a turbo can reach is about 900º C or more in the case of a gasoline engine or about 500º C in the case of a diesel engine. If we add to this the speed of rotation of the turbo, about 150.000 rpm, we can say that it is a very delicate piece and that requires great care.
Caring for a turbo engine
Maintaining a turbo is very important. You have to change the oil just when the manufacturer marks it and it is very important use the specific oil for our engine. In the event of a breakdown, we can easily exceed 1.000 euros.
As advice, we can say that it is necessary to avoid, as far as possible, accelerating with the engine cold. It is also important, when parking the car, to wait a minute before turning off the engine. In this way the oil continues to circulate through the turbo, which helps your cooling.
excellent site!, they are very clear in each of the explanations.
Excellent is what I needed to know… Thank you….