Cummins turbochargers frequently operate at high speeds and temperatures, with exhaust turbine temperatures exceeding 600°C and turbocharger speeds reaching over 12,000 rpm. Therefore, proper use and maintenance are crucial for ensuring the turbocharger's normal operation. The main precautions for using turbocharged gasoline engines are as follows:
After starting the engine, do not immediately accelerate or rev the engine. Generally, allow it to idle for 3 minutes, especially in winter, at least 5 minutes to warm up the engine and improve oil temperature and flow properties. This allows the lubricating oil to fully lubricate the rotor bearings before the turbocharger rotor starts operating at high speed. Also, immediately after starting the engine, the oil temperature is low and viscosity is high; revving the engine immediately after starting can cause excessive oil pressure, damaging the turbocharger oil seals.
Do not immediately shut off the engine when it is hot (for engines without a separate turbocharger cooling system). The turbocharger rotor bearings are lubricated and cooled by pressurized engine oil. If an engine is suddenly shut off while hot, the oil pressure will drop rapidly, causing the temperature of the turbocharger turbine to rise rapidly. Simultaneously, the turbocharger rotor continues to rotate at high speed due to inertia, which can cause the turbocharger rotor shaft and bearings to seize, damaging both the bearings and the shaft.
After the engine is suddenly shut off, the heat from the exhaust manifold is absorbed into the turbocharger housing, causing the oil inside to turn into carbon deposits, clogging the oil inlet and leading to insufficient lubrication of the bearings, accelerating wear between the turbine shaft and bearings. Therefore, the engine should be idled for 3-5 minutes before being shut off to allow the turbocharger temperature and rotor speed to decrease. It is especially important to avoid suddenly shutting off the engine after several sudden accelerations. Furthermore, it is worth noting that turbocharged engines are not suitable for prolonged idling; it should generally be limited to within 10 minutes, otherwise, insufficient lubrication of the rotor bearings due to excessively low oil pressure can cause damage.
The "accelerate-stop-coast in neutral" operation method is strictly prohibited. Sudden engine shutdown under full load and high temperature causes the oil pump to stop working, preventing the lubricating oil from carrying away the heat from the turbocharger components, which can damage the turbocharger.
Use the manufacturer-specified grade of engine oil and change the oil and oil filter regularly. The oil in the turbocharger's lubrication lines is prone to coking under high temperatures and should be cleaned regularly.
Clean or replace the air filter regularly to prevent dust and other impurities from entering the high-speed rotating compressor impeller, causing unstable speed or accelerated wear of the bushings and seals.
Check the turbocharger's operation. Before and after driving, check the engine intake pipe connections to prevent loosening or detachment, which could cause turbocharger failure or air short-circuiting directly into the cylinders. Check the turbocharger for oil and air leaks; check the turbocharger housing for overheating, discoloration, cracks, etc. If any are found, immediately identify and eliminate the cause or replace the affected part. If a turbocharger makes an unusual noise, it must not be used. The cause should be identified and eliminated.
