Turbochargers make car engines more powerful, but to prolong turbo life, car users need to note many important things.
There are two main types of turbocharger systems for automobile engines: turbocharger and supercharger. However, because turbochargers cost less, most cars today use turbochargers. In this article we will cover turbocharger type.
Bạn Đang Xem: Turbo tăng áp là gì? Những lưu ý khi đi xe động cơ turbo
What is turbocharger?
A car engine turbocharger (Turbocharger for short) is a type of forced induction device that increases the power of an internal combustion engine by bringing more compressed air into the combustion chamber. Compared to a naturally aspirated engine, an engine with a turbo can take in more air.
In a word, the use of turbochargers is to increase engine power without having to increase the number or capacity. cylinders in the engine. The normal pressure in air is 1 at. With turbochargers, the compression pressure will increase by about 0.408 – 0.544 at. So in theory, turbochargers help increase engine power by about 50%. In fact, although the performance is not perfect, the engine power is also increased by 30-40%.
Engine turbochargers are usually helical in shape. The internal structure includes: turbine impeller, pump impeller, shaft, bearing, turbo shaft lubricating guide.
The turbine impeller and the impeller are located in two separate chambers and are connected by a shaft. The turbine blades are located on the side of the cavity connected to the commutator to receive thrust from the engine exhaust stream. The impeller is located in the opposite compartment.
Working principle of turbocharger
The turbocharger is mounted on the engine exhaust manifold. Exhaust gas from the engine when discharged will rotate the turbine blades of the turbocharger. Due to the connection on the same shaft, when the turbine blade rotates, the opposite cavity pump impeller will rotate. Rotating impeller helps to draw clean air in and into the engine. As a result, the more exhaust gas, the faster the turbo rotates, which means more air is injected into the engine, thereby increasing the engine power.
However, in case the amount of gas is sucked in with too high pressure and temperature, the volume will increase, the oxygen density is not much. Therefore, a cooler is installed in front of the vehicle to cool this intake air.
Another problem, because the turbocharger is located on the exhaust pipe, if the exhaust pressure is too high, it will easily create a pressure back into the combustion chamber, causing engine damage. To overcome this point, a safety valve is installed to help guide excess exhaust gas out.
Why is there turbo lag?
Turbocharged engines always have a certain lag (also known as turbo lag). The reason is that for the turbo to rotate, a large exhaust flow is required, the faster the turbo rotates, the stronger the exhaust flow must be. While this is not possible when the engine is operating at engine rpm short. Therefore, when stepping on the accelerator, the turbo has to wait for the engine rpm to go up before turning quickly, causing turbo lag or turbo lag.
Types of turbochargers
Single turbo (single turbocharger) is a turbocharger with a traditional structure. Single turbo is currently the most commonly used type today.
Advantages: Simple installation, high turbine efficiency, suitable for use in small engines to help generate power equivalent to larger capacity naturally aspirated engines.
Cons: Single turbines tend to have a limited rpm range, so performance is poor at low speeds and in idling engine mode, with a certain lag.
Twin-scroll turbo (double coil turbocharger) has the same structure as a single turbo but has up to two turbine tubes (the traditional type has only one tube). These two pipes will connect to two different exhaust pipes. For example, if the engine has 4 cylinders in line in the order 1-3-4-2, cylinders 1 and 4 will share the same exhaust pipe and connect to the first turbine tube, cylinders 2 and 3 will share a common exhaust pipe and connect to a second turbine tube. Because the turbo has two turbine tubes that receive the exhaust, it is called a dual coil exhaust turbocharger.
Advantages: Making the most of exhaust pressure, good performance at low – medium speeds.
Xem Thêm : Tổng quan về hệ thống điện trên ô tô
Cons: Complicated structure, high cost.
Twin-turbo or Bi-turbo (double turbocharger) uses two traditional turbochargers at the same time. The size of these two turbochargers may be different. The layout also has many forms such as: each turbocharger is used for each cylinder series (V6 engine, V8 …), one set is used for low rpm – one is used for high rpm …
Advantages: Overcoming turbo lag, optimal power at many different rpm ranges.
Xem Thêm : Tổng quan về hệ thống điện trên ô tô
Cons: Complicated structure, high cost.
Besides the above common types, there are many other turbochargers such as: Electric turbo, Variable twin-scroll turbo, Variable Geometry Turbocharger…
Are turbo machines durable?
The life of the turbocharger is quite long. Under ideal working conditions, turbocharger life can be up to 200,000 – 300,000 km or more depending on operating conditions and maintenance.
How to identify a broken turbo?
When the turbocharger has a problem or damage, the car often has the following identification signs:
- Engine makes strange noisesthe engine is noisier than usual, there is a howling noise, especially when accelerating quickly.
- The car is using more oil than usual.
- The car is weak more, the car accelerates sluggishly, no longer as fast and loaded as before.
Common failures in turbo engines
Turbo is leaking oil
The turbo system needs to be lubricated and cooled just like the engine. So there will be a system that directs oil from the engine to the turbo. After many years of work, this oil transmission system, gaskets and seals can be worn and degraded leading to leaks. As a result, the turbo is leaking oil, lacking oil, and even running out of oil. The telltale signs are usually turbo howling, the engine is noisier than usual, not as smooth as before.
Compressed air duct problem
The gas pipeline system from the turbo to the engine combustion chamber is usually made of plastic / rubber or alloy on some high-end cars. To prevent leakage, the pipe end has a sealing ring and a tightening belt. However, after many years, the pipeline can be degraded, the gasket is open, causing compressed air to leak out. At this time, the air intake from the turbo into the engine will not be as much as before, making the engine weaker.
Silver, worn turbo ball
Working for a long time in harsh conditions will cause silver and ball wear. This reduces turbo performance. Common telltale signs are engine buzzing, abnormal oil consumption, significantly reduced engine power…
Notes when riding a turbo
The durability of a turbo car will largely depend on how it is operated and maintained. Therefore, to prolong the life of the turbo engine, users should note a few things as follows:
Limit movement right after starting the engine
Today’s modern car engine uses an electronic fuel injection system, so it will not be necessary to let the car start for too long before moving. However, if you use a turbocharged engine car, many experts recommend that the vehicle be idle for a few minutes before rolling.
The reason is that the turbocharger uses the same lubricating oil as the engine. When the car has just started, the engine oil is still cold (more dense) so it circulates more slowly. And now the oil also needs time to pump up. Therefore, the engine and turbo lubrication effect is not good.
The ideal temperature for the oil to circulate to lubricate the parts is from 80 to 95 degrees Celsius. The time to wait for the oil temperature to rise will depend on the different engine heating mechanism in each vehicle. However, it is usually recommended to let the car start the engine for 2-3 minutes before rolling.
Do not turn off the machine immediately after stopping
With a vehicle using a naturally aspirated engine, turning off the engine immediately after stopping the vehicle is not too affected. However, with vehicles using turbocharged engines, this should be limited. Because with turbocharged engines, the heat generated is very high. Oil acts as both a lubricant and a coolant, so it absorbs heat from the engine.
If the engine is turned off suddenly while the engine is still hot, the oil in the engine will not be circulated, but only locally exposed in some hot locations. This easily causes the oil to degrade in quality, the additives in the oil to decompose faster, and the oil to degrade faster. So when riding a turbo, the driver should pay attention to slow down a few kilometers before the destination. After stopping the car, you should let the engine start for 2-3 minutes, then turn off the engine.
Avoid driving at too low rpm
The turbocharger is driven by the engine exhaust. If the engine is operating at too low a rpm, the turbo will not reach a certain rev threshold. This means that the vehicle’s power will not reach the optimal level. Therefore, driving at too low rpm thinks that it will save fuel, but it is not.
Pay attention when the car turns a corner
Unlike a naturally aspirated engine, a turbocharged engine will have a certain delay when accelerating. So if you don’t pay attention to this delay, turbo riders are prone to understeer or overdrive phenomenon when cornering, leading to the vehicle skidding, losing control, even car lost control. So an important note when riding a turbo is not to step on the accelerator too deeply when driving out of a corner.
Use gasoline with the correct octane rating
In vehicle manuals, manufacturers often recommend very clearly about the gasoline with the right octane rating. Users should adhere to this recommendation. Gasoline with a lower octane rating should not be used. Because it can cause the car to detonate the fuel at the wrong time, affecting the life of the engine and turbocharger.
Note about lubricating oil
Turbochargers use the same lubricant as the engine. In some turbocharged vehicles, there is no significant loss of oil during a change cycle. But in some other cars, the amount of oil loss is higher than usual, so it needs to be replenished periodically. Therefore, it is best for users to consult the car company for instructions on how to properly check and add oil.
Change fuel filter on time
The turbocharger rotates with the exhaust from the engine and is therefore very sensitive to the exhaust quality. If the fuel filter is dirty, contaminated gasoline will enter the combustion chamber, and the ratio of the mixture of gasoline and air will be wrong. This affects the quality of the exhaust gas and directly harms the turbo. Therefore it is necessary to check and change car fuel filter periodically on time.
Maintenance of the cooling system when charging periodically
The supercharged intake air cooling system should be serviced every 160,000 km or sooner depending on operating conditions. Besides, you should also check the cooling system, change the cooling water regularly.
Check the high-pressure gas pipeline system periodically
In many cases, the turbocharger fails due to a malfunction in the high-pressure gas pipeline system, affecting the amount of air intake into the engine. At this point, the turbo has to work harder to compensate. Therefore, it is recommended to check the high-pressure gas pipeline system periodically to promptly handle if a leak occurs.