How are turbochargers lubricated and cooled?
The oil from the main oil passage of the engine lubrication system enters the supercharger through the oil inlet on the intermediate body of the supercharger to lubricate and cool the supercharger shaft and bearings. The oil then returns to the engine oil sump through the oil outlet on the intermediate body. An oil seal is installed on the supercharger shaft to prevent oil from escaping into the compressor or turbine volute. If the oil seal is damaged, it will lead to increased oil consumption and blue smoke from the exhaust.
Due to the large heat load of the gasoline engine supercharger, a cooling water jacket is installed on the turbine side of the intermediate body of the supercharger, and a hose is connected to the cooling system of the engine. The coolant flows from the coolant inlet on the intermediate body into the cooling water jacket in the intermediate body, and flows back to the engine cooling system from the coolant outlet. The coolant is continuously circulated in the cooling water jacket of the intermediate body to cool the supercharger shaft and bearings.
Some turbochargers do not have a cooling water jacket in the intermediate body, and only rely on oil and air to cool them. If the engine is stopped immediately after working under heavy load or high speed, the oil may burn in the bearing due to the bearing temperature being too high. Therefore, such turbocharged engines should be run at idle for at least 1 minute before shutting down.
