Turbochargers are a cost-effective alternative for increasing engine power and efficiency. They operate on the following principles:
Exhaust Gas-Driven
Turbocharger assemblies harness the kinetic energy contained within the high-temperature exhaust gases expelled from the engine during combustion. Instead of allowing this energy to dissipate into the atmosphere, they capture it and convert it into useful work to enhance engine performance.
Turbine and Compressor
Turbos consist of two primary components: the turbine and the compressor. The turbine is placed within the exhaust stream and is driven by the flow of exhaust gases. Meanwhile, the compressor located on the engine’s intake side — is connected to the turbine via a common shaft.
Air Compression
The exhaust gases impart rotational energy to the turbine, forcing it to spin at high speeds. Next, this motion is routed through the shaft to the compressor. The component then pulls ambient air, compresses it, and delivers it to the engine’s intake manifold at high pressure and density levels.
Boost Control
Turbochargers typically incorporate boost control systems to optimize engine performance under varying operating conditions. This regulates the amount of boost pressure the compressor generates, adjusting it based on speed, load, and driver input.
Intercooler (Optional)
Some turbocharged engines feature an intercooler, which is a heat exchanger placed between the compressor outlet and the intake manifold. This component lowers the temperature of the compressed air before it enters the engine, improving its density and increasing the oxygen content.
Enhanced Features
Turbochargers have evolved to become more efficient, incorporating advanced elements and features to optimize performance. Here are some of the most notable turbo types and innovations:
- Wastegate turbochargers: These feature a wastegate mechanism that controls the amount of exhaust gas flow to the turbine, regulating boost pressure and preventing over-boost.
- Turbo compounding turbochargers: These utilize additional turbines connected to the engine crankshaft to recover energy from exhaust gases.
- Two-stage turbochargers:These employ two sets of turbines and compressors, often arranged in series, to provide sequential boosting.
- Variable geometry turbochargers (VGT): These feature adjustable turbine vanes or nozzles, allowing for optimized airflow characteristics.
- Electronic control turbochargers: These have electronic actuators and sensors to control turbocharging operation, optimizing performance and emissions.
- Actuation, sensor turbochargers: These use advanced actuation mechanisms and sensors to monitor and adjust parameters such as boost pressure and turbine speed.
- High-pressure turbochargers: These are designed to withstand higher boost pressures, enabling them to deliver increased air intake.