The turbocharger is a core component that boosts the efficiency of excavator engines; in essence, it is an air compressor driven by exhaust gas. By recovering the exhaust energy of the engine, it greatly increases the density of air entering the cylinders, thereby significantly enhancing power without increasing the engine displacement. Its working principle can be summarized into the following four-step cycle:

I. Energy Recovery (Exhaust Gas Driven)

High-temperature, high-velocity exhaust gas discharged by the engine is introduced into the turbocharger’s turbine housing, where it impacts and drives the internal turbine impeller to rotate at a high speed (the rotational speed can reach over 100,000 revolutions per minute (rpm)). This process converts the thermal and kinetic energy of the exhaust gas—which would otherwise be wasted—into mechanical energy that powers the turbine.

II. Forced Intake (Air Compression)

The turbine impeller is rigidly connected to the compressor impeller on the other end via a common shaft. As the turbine rotates at high speed, the compressor impeller spins synchronously, drawing in fresh air from the air intake pipe. The centrifugal force generated by the rotating impeller flings the air out at high speed, compressing it in the narrow passages of the compressor volute. This causes a simultaneous rise in the air’s pressure, density and temperature.

III. Cooling for Efficiency (Intercooling)

The temperature of compressed air rises sharply (can exceed 90℃). High-temperature air undergoes thermal expansion, which in turn reduces its oxygen content. For this reason, the compressed air must pass through an intercooler for cooling. After cooling, the air density is further increased and its oxygen content is higher, creating optimal conditions for complete fuel combustion.

IV. Power Enhancement (Complete Combustion)

The cooled, high-density, oxygen-rich air enters the engine cylinders and mixes with precision-injected diesel fuel. This allows more fuel to burn fully and rapidly, enabling the engine to deliver 20% to 50% more power and torque than a naturally aspirated engine of the same displacement. In particular, it improves the torque response of excavators at low rotational speeds, perfectly adapting to their heavy-duty, intermittent operating characteristics