What is a turbocharger?
Turbocharger in English is called Turbocharger. It is a system suitable for diesel engines. Can be on trucks, cars, or any engine, including airplane or boat engines. This is a type of forced induction device that helps increase the power of an internal combustion engine by introducing more compressed air into the combustion chamber. Compared to a naturally aspirated engine, a turbo engine can take in more air.
To put it simply, the purpose of a turbocharger is to increase engine capacity without having to increase the number or capacity of engine cylinders. The normal pressure in air is 1 atm. With turbocharger, compression pressure will increase by about 0.408 – 0.544 atm. So in theory, turbocharger helps increase engine power by about 50%. In fact, although the performance is not perfect, the engine capacity is also increased by 30 – 40%.
History of turbocharger formation
Forced air intake dates back to the late 19th century, when Gottlieb Daimler patented the technique of using a gear-driven pump to push air into an internal combustion engine in 1885.
The 1905 patent of Alfred Büchi, a Swiss engineer working at Gebrüder Sulzer is often considered the birth of the turbocharger. This patent is for a radial engine that combines an axial flow exhaust gas turbine and compressor mounted on a common shaft. The first prototype was completed in 1915 with the aim of overcoming the loss of power experienced by aircraft engines due to reduced air density at high altitudes. However, the prototype was unreliable and did not go into production
Another early patent for turbocharging was registered in 1916 by French steam turbine inventor Auguste Rateau, intended for use on Renault engines used by French fighter aircraft.
The first commercial application of turbocharging was in 1925, when Alfred Büchi successfully installed a turbocharger on a 10-cylinder diesel engine, increasing power from 1,300 to 1,860 kilowatts (1,750 to 2,500 horsepower). . This engine has been used by the German Ministry of Transport for two large passenger ships, “Preussen” and “Hansestadt Danzig”.
Automobile manufacturers began researching turbochargers in the 1950s, but the problems of “turbo lag” and the bulky size of turbochargers could not be solved at the time. there. The first turbocharged cars were the Chevrolet Corvair Monza and Oldsmobile Jetfire, introduced in 1962. After the 1973 oil crisis and the 1977 Clean Air Act amendments, turbocharging became more popular. in automobiles, as a method to reduce fuel consumption and emissions.
Structure and operating principle
Structure of turbocharger
Turbocharger structure is simply understood. It consists of two main parts: the turbine and the compressor.
These are 2 propellers mounted on a shaft. Each fan has one shaft end. The engine’s exhaust is directed to a fan. This is called a turbine whose purpose is to rotate the shaft and rotate the second fan with the opposite effect, called the compressor. This compressor will be responsible for compressing air into the engine’s air intake chamber.
Operating principle of turbocharger
With a simple operating principle, turbocharger Installed on the engine exhaust pipe. The turbocharger’s turbine blade rotates as exhaust gas from the engine flows past it.
And because it is connected on the same shaft, when the turbine blade rotates, the pump impeller in the opposite compartment will rotate and simultaneously suck in clean air, compress it and then feed it into the engine.
As a result, when the car accelerates, the more exhaust gas is released, the faster the turbo’s rotation speed will be, meaning more air is fed into the engine, thereby increasing engine power.
Advantages and disadvantages of Turbocharger
Similar to other types of devices, turbosupercharger has the following advantages and disadvantages:
About advantages
- Turbocharging helps increase engine power, not increasing the number of cylinders or capacity. Thereby, helping to reduce fuel consumption.
For example: In case of using a turbo engine, the engine capacity can increase from 30% – 40% compared to an engine that does not use a turbo.
About disadvantages
- Engines using turbochargers require stronger pistons and crankshafts than engines that do not use turbochargers.
- Turbos generate heat, causing the engine to heat up. Therefore, the radiator cooling system is also required to be larger.
- Because turbines rotate at about 100,000 – 250,000 rpm, turbocharged engines require an abundant supply of oil.
Turbo lag phenomenon (Turbo lag)
Turbocharged engines always have a certain delay (also known as turbo lag phenomenon). For the turbocharger system to work effectively, it needs to rotate faster than a minimum speed so that the air compressor reaches enough pressure to draw more air into the engine. At low engine speeds, the velocity of the exhaust air flow is not fast enough to rotate the air compressor to this minimum number of revolutions. Therefore, there needs to be a certain delay for the turbo to reach its effective working speed and bring perceptible changes to the vehicle’s performance and power.
Currently, the engine with the lowest turbo lag of 0.7 seconds belongs to Ferrari with a 3.9-liter twin-turbo V8 engine codenamed F154.
Current types of turbochargers
There are many types of turbos on the market today, each with its own characteristics and differences. Below, CarOn will introduce the turbo types that are of most interest
Single engine (Single turbo)
Single turbo (single turbocharger) is a turbocharger with traditional structure. Single turbo is currently the most commonly used type today.
Advantage
- Effectively increase engine power. Simple installation and calculation.
- Allows the use of smaller engines to produce power comparable to larger naturally aspirated engines.
Defect:
- Single turbines tend to have a limited RPM range. This makes size an issue, as you will have to choose between torque or power.
- Turbo response may not be as fast compared to other turbo models.
Twin turbocharger (Twin-Turbo or Bi-Turbo)
Twin-turbo or Bi-turbo uses two traditional turbochargers at the same time. The sizes of these two turbochargers may be different. The layout also has many forms such as: each turbocharger is used for each cylinder bank (V6, V8 engines…), one set is used for low rpm – one set is used for high rpm…
Advantage
- For parallel twin turbos on “V” engines, the benefits (and disadvantages) are very similar to the single turbo model.
- For sequential turbos or using a turbo at low RPM and also at high RPM, this allows for a much flatter, wider torque curve. Low-end torque is better, but power won’t drop at high RPM like with a small turbo.
Defect
- High cost and complexity, as the turbo components had to be nearly doubled.
Twin-scroll turbo
Twin-scroll turbo has the same structure as a single turbo but has 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 an exhaust pipe and connect to the first turbine pipe, cylinders 2 and 3 will shares a common exhaust pipe and connection to the second turbine pipe. Because the turbo has two turbine pipes receiving exhaust gas, it is called a dual-scroll exhaust turbocharger.
Advantage
- More energy is sent to the exhaust turbine
- Wider RPM ranges can be increased based on different reel designs.
- More valves can be overlapped (both exhaust valves are open at the same time) without obstruction, allowing for more flexible adjustment.
Defect
- Requirements for specific engine layouts and exhaust designs (e.g. I4 and V8, where 2 cylinders can be included in each scroll of the turbo, at intervals) are more difficult and complex.
- Cost and complexity are higher than traditional single turbines.
Electric turbo engine (Electric turbo)
Full Electric Turbocharger Technology is a new technology that will enable vehicle manufacturers to meet future stringent emissions legislation, while providing excellent response throughout the engine operating range, even at low rpm. low engine and vehicle speed. FETT is the ultimate solution for extreme engine downsizing and improved engine performance using a single-stage turbocharger.
Advantage
- By connecting an electric motor directly to the compressor gear, turbo lag and emissions can be virtually eliminated by turning the compressor using electrical power when needed.
- By connecting an electric motor to the exhaust gas turbine, wasted energy can be recovered.
- Very wide effective RPM range with even torque.
Defect
- High cost and complexity.
- Weight becomes an issue, especially with the addition of an onboard battery, which will be needed to provide enough power to the turbo when needed.
Variable twin-scroll turbo
A variable twin-scroll turbo combines VGT with a twin-scroll setup, so at low revs one of the scrolls is completely closed, forcing all the air into the other. This results in good turbo response and low-end power. As you accelerate, one valve opens to allow air into the other coil (this is a completely variable process, meaning the valve opens in small increments), you get good high-end performance.
Advantage
- Significantly cheaper (in theory) than VGT, thus making an acceptable case for turbocharging petrol engines.
- Allows for a wide, flat torque curve.
- Stronger in design than VGT, depending on material choice.
Defect
- Cost and complexity are higher than using a traditional single or dual scroll turbo.
- This technology has been researched before, but does not seem to have caught on in the manufacturing world due to technological challenges.
Above is the information about the Turbo Booster System that CarOn has compiled. Hopefully this additional knowledge will help readers understand more about Turbo to easily choose the product that best suits their needs.
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