Structural principle of Changzhou marine turbocharger

Firstly, let's talk about the general structural principle of a turbocharger. The exhaust gas turbocharger is mainly composed of a pump wheel and a turbine, as well as other control components. The pump wheel and turbine are connected by a shaft, which is the rotor. The exhaust gas from the engine drives the pump wheel, which drives the turbine to rotate. After the turbine rotates, it pressurizes the intake system. The turbocharger is installed on the exhaust side of the engine, so the working temperature of the turbocharger is very high. Moreover, the rotor speed of the turbocharger during operation is very high, reaching tens of thousands of revolutions per minute. Such high speed and temperature make common mechanical needle or ball bearings unable to work for the rotor. Therefore, turbochargers generally use fully floating bearings, lubricated by oil, and cooled by coolant. Previously, turbochargers were mostly used in diesel engines because the combustion methods of gasoline and diesel were different, so the form of turbochargers used in engines was also different.

A gasoline engine is different from a diesel engine in that it enters the cylinder not with air, but with a mixture of gasoline and air. Excessive pressure can easily cause detonation. Therefore, when installing a turbocharger, it is necessary to avoid detonation, which involves two related issues: high temperature control and ignition time control.

After mandatory turbocharging, the temperature and pressure during compression and combustion of gasoline engines will increase, leading to an increased tendency for detonation. In addition, the exhaust temperature of gasoline engines is higher than that of diesel engines, and it is not advisable to increase the valve overlap angle (the time when the intake and exhaust valves open simultaneously) to enhance the cooling of the exhaust. Reducing the compression ratio can also cause incomplete combustion. Moreover, gasoline engines have higher engine speeds than diesel engines, resulting in significant changes in air flow rate, which can easily cause delayed turbocharger reactions. Engineers have made targeted improvements to address a series of issues with the use of turbochargers in gasoline engines, enabling them to also use exhaust gas turbochargers.