Modern cars are often equipped with a turbocharger - this way you can significantly increase the power and characteristics of even low-power and low-volume engines. As you know, no engine can work properly without a certain amount of air. To burn one liter of fuel in the combustion chambers, you need at least 11 thousand liters of oxygen. But in order for air to fall into the cylinders, it must pass through the filters, the intake manifold, bypass the throttle and then get into the gap of the seat and the valve itself. The need for a motor in the air is never fully satisfied. The turbocharger gives air acceleration and pumps it into the combustion chambers. During operation, the turbine may make sounds. For many car owners, this is alarming. Let's find out how this unit is arranged, whether the whistle of a turbine on a diesel is dangerous during acceleration, and what this says.
About creating a turbine
Most car owners are seriously convinced that turbo engines are a relatively recent invention. It is believed that they appeared in the second half of the 20th century, when almost all models of the German automobile industry were equipped with turbochargers. But it is not so.
The birth date of the turbo engine is considered to be 1911. It was then that the American engineer Alfred Buchi was able to obtain a patent for the industrial production of a device that allows several times to increase the power and technical characteristics of conventional motors.
But with all the efficiency of these first turbines, they were bulky in size and many times increased the weight of the engine. The development of turbocharging for passenger cars stopped, but turbines were used very actively on trucks. In the United States, carmakers were in no hurry to industrially install a boost system. Then (however, as now) a bet was placed on voluminous atmospheric power units. There is even a proverb “nothing replaces volume”.
In Europe, fuel was treated more economically than in the United States. In addition, in the 20th century, Europe experienced a fuel crisis. Automakers began to reduce the volume of engines, while increasing power. This helped the boost system. The technology has improved, the structural elements have become lighter. However, among the shortcomings was still high fuel consumption - turbocharging among ordinary car owners did not find popularity.
Element in a diesel engine
As you know, a diesel engine was developed in 1893. Over time, its design was finalized, many details were subjected to repeated changes and modifications. Engineers worked on ways to supply the fuel mixture, as well as on its balance itself. Then the engineers developed a turbine designed to increase the productivity and performance of the unit due to a more complete combustion of fuel in the cylinders. This process is based on the compression of air in the internal system - this made it possible to increase the density of the supplied air. So the mixture burned completely, and less harmful emissions were released into the atmosphere.
There are low pressure and high pressure turbines. High-boost devices are more efficient as well as complex in design.
Design
A modern turbocharger is a device consisting of the following components. These are two casings, each of which is equipped with a compressor and a turbine. These casings are made of heat resistant cast iron alloys. The turbine is equipped with a special wheel - it also has resistance to high temperatures.
Also in the design there are special bearings. Their bodies are made by casting from special bronze alloys. A shaft passes through them, which connects the compressor wheel to the turbine rotor. Support and thrust bearings are also available .
The principle of operation of a turbocharger
The algorithm of work is as follows. The combustion products that are discharged from the exhaust manifold go to the exhaust pipe of the turbocharger. Then they pass through the turbine housing - the channel in the housing has a variable cross-section. Exhaust gases as they move along the channel increase their speed and act on the turbine wheel - under this influence it rotates. The number of revolutions of a turbine rotor depends on many factors. The average rotation speed is 1500 rpm.
The air outside, passing through the air filters, is thoroughly cleaned of impurities and in a compressed form will fall into the intake manifold. Then the channel closes. The mixture is further compressed and ignited. Next, the exhaust manifold opens. An intercooler is installed at the entrance to the combustion chambers.
It is needed to cool the hot air coming from the turbocharger. Thus, the density increases and the volume of oxygen decreases. A larger amount of air enters the cylinder, which, after mixing with the fuel, will burn more efficiently. Due to this, power increases significantly and fuel consumption decreases.
If the turbine whistled
In the process, a huge amount of air passes through it, which is then mixed with fuel, increasing the weight of the mixture. Oxygen is pumped under high pressure - under the hood, there may be a whistle both at idle and during movement. One reason is a leak in the system.
These sounds can alert. But do not immediately go to the diagnosis in the service station. You can try to fix the problem yourself. First of all, experts recommend checking each air pipe in the engine for leaks. Often, when a turbine whistles on a diesel engine during acceleration, there is an excess air leak. To fix the problem, it is enough to replace the gaskets, tighten the clamps and fasteners.
In case of wear of the pipes, they are replaced with new ones. They are not subject to repair, and it is not recommended to install the ones that were in use.
If the system is tight and the whistle is still audible, then a deeper diagnosis is necessary, because the turbine is a very important technical element that must work stably. Many do not know, but a small whistle of a turbine on a diesel engine during acceleration is a common thing. But if the device roars, then this is already associated with problems.
How does the turbine whistle?
Often, compressors make these sounds when gaining speed in the range from 1.5 to 2.5 thousand revolutions. It doesn’t matter how abruptly accelerate. Whistling will still occur. Sounds do not stop, even if the speed drops. In this case, the engine characteristics do not change. Just the amount of air passing through the turbocharger passes through special openings, which over time have lost their shape. As a result, the driver hears a nasty whistle of air from the engine compartment during acceleration.
Light whistling sounds can be observed even on new turbines. But it goes fast. And after a while, if the device is working properly, only the sounds of the motor are audible. If the turbine whistles, but the speed drops, replace the hose, which connects it to the intercooler. Sometimes the air heat exchanger itself may be to blame. If a whistle appeared during acceleration, similar to a broken intercooler, you need to conduct an audit - it is easier to repair it than a turbine. The part can be soldered, or in case of serious malfunctions replaced with a new one.
Why is the intercooler breaking through? The fact is that the element is installed in front of the car. Not only is it located in front of the radiator, it is also fixed almost at the bottom of the bumper. Therefore, various stones can fall here.
This is one of the main reasons why the turbine whistles on a diesel engine during acceleration. By the way, the intercooler is not installed on all turbocharged engines. This must be taken into account when diagnosing. In some cases, the compressor is oil-cooled (for example, on a Kammnis diesel engine at GAZelle-Business).
Causes of Whistling
The speed at which the fully operational turbine impeller rotates is more than ten thousand per minute. Certainly, the whistle of a diesel turbine during acceleration is a sign of depressurization in the system connections. The turbine whistles due to the passage of compressed air through the cracks. You can fix these problems yourself. To do this, find the place that is the cause of these sounds.
Also, whistling of the turbine during speed gain may occur due to the passage of air anywhere from the intake manifold to the intercooler. Also, sound will occur if there are gaps between the cylinder head and the intake manifold (loose contact between the surfaces of the unit). If the gasket is broken, then this is also one of the reasons for whistling. Sound can also occur if third-party objects get inside the mechanism.
Other symptoms of malfunctions
Not only a whistle during acceleration can indicate a malfunction of the unit. There are other signs. From them you can determine that the turbine needs repair. We will consider typical unit malfunctions by exhaust color.
Blue smoke
This is the first and most characteristic sign of damage. When speeding up, blue smoke will be emitted from the exhaust pipe. Moreover, if the motor runs at lower speeds, it will not be. The reason is the burning oil that gets into the engine cylinders due to leaks from the turbocharger. A characteristic whistle may also be heard when speeding up.
Black smoke
Smoke of this color indicates that a rich mixture burns in the cylinders due to air leakage in the discharge lines or in the intercooler. Another reason is the electronic control system. She can malfunction. Additionally inspect the condition of the nozzles.
White smoke
The reason for the formation of such smoke must be sought in the clogging of the turbine drain oil line. If oil smudges are found on the unit’s body or if it is on the air duct nozzles, this is caused by a clogged system in the air supply channel. The turbine axis could also be coked. As a result, unnatural color gases come from the exhaust.
Conclusion
We examined why the turbine whistles on a diesel engine during acceleration, the reasons for the appearance of these sounds. In most cases, they are associated with air leaks. You can fix the depressurization with your own hands. But if the breakdown is more serious, then here you can’t cope on your own. Modern turbines have a complex structure, and repairs are best left to professionals. They are able to determine by sound what the turbine is whistling about.