Types of turbochargers

Types of Turbochargers

Twin, Bi, Single, Triple, Quadro, Hybrid - a lot of seemingly incomprehensible words and questions, but what are they exactly? In this article, we'll explore all types of turbochargers found in both vintage and modern cars, how they work, their differences, and where they're used.

Single Turbo

The most common type of turbocharger is a Single Turbo, also known as free-floating, which gets its name because the exhaust gas flow is not controlled. A single-stage turbocharger is the basic type of boosting used in gasoline and diesel engines. It operates on the principle of using the energy of exhaust gases to drive the turbine wheel, which then drives the compressor wheel. The boost pressure generated by the turbocharger is directly related to the engine's rotational speed and the size of the wheels. It is a simple and proven method of boosting that allows for an increase in engine power while maintaining relatively low production and maintenance costs.

Single turbo controlled with wastegate valve or variable geometry. These are more technologically advanced turbines that offer greater flexibility in terms of boost performance. They are used in both gasoline and diesel engines. In the photo below, we see an 887552-0001 turbocharger from Garrett, designed for Mercedes-Benz Sprinter cars with an OM642DE30LA 3-liter engine, which were produced in 2019.

Twin Turbo

Twin turbo, also known as parallel twin turbo, is an advanced boosting system consisting of two identical turbochargers arranged in parallel. Each turbocharger has its own turbine and compressor wheel, allowing for optimization of performance at different engine speed ranges. Twin turbo is commonly used in large displacement diesel and gasoline engines, where it provides better responsiveness at low engine speeds and high power output at higher engine speeds. The use of two turbochargers allows for increased power output while maintaining the efficiency and performance of the engine. Here is the BMTS 40008485+40008486 twin-turbocharges, mounted in the 6.0-liter W12 Bentley Bentayga engine, with 600 km (447 kW) and were used in models produced from 2015 to 2019.

Bi-turbo

The next turbocharger type we'll explore is Bi-turbo, also known as sequential turbocharging, which is a boosting system based on two turbochargers arranged in sequence. The system consists of a "small" (low pressure) and "large" (high pressure) turbochargers. The smaller turbocharger activates at low engine speeds, as it requires less energy for quick start-up. Once a set boost pressure or engine speed is reached, the larger turbocharger begins to pump, allowing for greater air delivery. The use of such technology allows for low fuel consumption (up to 8l/100 km) with high power output (over 200 HP). It is commonly used in diesel engines, allowing for optimal use of exhaust gases. Each turbocharger is responsible for boosting at certain engine speeds. A good example is the Bi-Turbo 823559-0005+823540-0004 system, which was used in diesel engines in the Opel Astra K 1.6 CDTI model since 2015.

Triple or Quad turbo

As the name suggests, this involves three or four turbochargers on a single engine. The principle of operation is similar to bi-turbo, with the turbochargers working sequentially. This allows for high power output with relatively low fuel consumption. However, the construction is complex and expensive to maintain. Currently, only BMW engineers have implemented similar projects, although the brand has since abandoned the Quad Turbo System due to high production and maintenance costs for cars with this type of turbocharged engine. One of such projects of this brand was a 3-liter BMW N57S Tri-Turbo engine, with direct injection, which was set in BMW M550D, X5 M50D, and X6 M50D cars.

Hybrid boosting technology

This is a general term, often used for modified or tuned turbochargers. With the development of electromobility, turbines are also becoming electrified. Currently, two solutions on the market combine known turbo boosting technology with electric motors.

The first type is electric compressors, which provide a quick boost for engine start-up to operating speeds where the turbochargers become effective. Audi was the first to use this technology in their 4.0TDI, where the twin-turbo setup was supported by an electric compressor from Valeo.

The second type is a true breakthrough in the market - the use of an electric motor in the turbocharger's bearing housing. This design allows the electric motor to spin the turbocharger shaft at low engine speeds, using battery power. Once sufficient boost pressure is reached, the exhaust gases power the turbocharger, which also charges the battery.

Hybrid turbocharger

It is an innovative solution used in motorsport, allowing for increased engine power through modification or replacement of the original turbocharger with a more efficient one. The main goal of hybrid turbochargers is to increase performance without requiring significant changes to the intake and exhaust systems. Larger components and optimized construction in hybrid turbochargers result in higher performance parameters, leading to increased engine power and torque. We present a hybrid turbocharger IS38 ball bearings by IHI Turbo Systems, in which a compressor housing, compressor wheel and shaft and wheel were modified. It is dedicated to a 2-liter Audi TTS Quattro Roadster with a power of 228 kW, produced in 2014-2019.

How to increase turbocharger effectiveness:

1. Mapping optimization: Adjusting the fuel injection and turbocharger control maps to new engine operating parameters, ensuring optimal performance under changed engine conditions. 

2. Control modification: Implementing advanced electronic or vacuum control, allowing for better turbocharger control and optimal performance. 

3. Increasing airflow: By removing restrictions in the intake and exhaust systems and using more efficient air filters and exhausts, airflow and exhaust gases can be increased, improving turbocharger performance. 

4. Mechanical reinforcement: To increase durability, reinforced components such as shafts, bearings, or housings can be used to prevent damage during increased boosting.

Types of compressor wheels

The development of technology and emissions regulations have led to the evolution of turbochargers over time. As the moving elements rotate faster and are exposed to higher temperatures, compressor wheel designs have also evolved to meet the changing demands.

Types of compressor wheels for turbochargers include standard compressor wheel, CNC machined compressor wheel, and tuning compressor wheel.

Types of turbocharger compressor wheels include standard compressor wheel, CNC compressor wheel, and tuning compressor wheel. Here's a brief explanation of the differences and functions of each type of turbocharger compressor wheel:

1. Standard compressor wheel: This is the basic type of compressor wheel used in standard, factory-made turbochargers. It features a typical shape and design, providing basic performance as accepted by the manufacturer.

2. CNC compressor wheel: CNC (Computer Numerical Control) compressor wheels are manufactured using precise CNC machines, allowing for more accurate shaping and optimal fitting of the blade shape. CNC compressor wheels can improve airflow and turbocharger performance, leading to increased engine power and torque.

3. Tuning compressor wheel: Tuning compressor wheels are specifically designed for motorsport enthusiasts who want to achieve even greater power and performance from their turbocharger. They typically have more aggressive blade shapes and are optimized for maximum airflow. These compressor wheels can be used in modified or high-performance applications, providing increased power and responsiveness for the engine.

In short, each type of compressor wheel aims to increase turbocharger performance by optimizing airflow. CNC and tuning compressor wheels are particularly focused on providing better performance compared to standard compressor wheels.

Electric turbos

An electric turbocharger, also known as an e-turbo, uses an electric motor to drive the compressor wheel. This eliminates the delay in delivering air to the engine, improving efficiency and responsiveness. It is primarily used in internal combustion engines, providing maximum power and torque at various engine speeds. Additionally, e-turbos can be used to recover energy from exhaust gases through electrical energy regeneration.

Electric turbochargers are mainly used in internal combustion engines, particularly in racing vehicles and high-performance cars, where achieving maximum power and torque at various engine speed ranges is crucial. Furthermore, e-turbos can be used to recover energy from exhaust gases through electrical energy regeneration. In the photo presented below, there is a new Electric turbocharger 904398-0004 which is dedicated to Mercedes-Benz AMG cars.