The principle and use of modern turbochargers
The principle and use of modern turbochargers
The turbocharger consists of a turbine, a compressor, a rotor assembly, a bearing mechanism, an intermediate and a sealing device. The principle of operation is to use the high temperature and high pressure exhaust gas from the engine to drive the exhaust gas turbine rotation, the exhaust gas turbine drives the same shaft of the compressor to rotate together, the compressor compresses the air filtered by the air filter, so that the air is compressed and pressurised into the engine cylinder, to improve the engine air intake device, to reduce the emission of harmful substances such as CO, HC, CL particles in exhaust gas. The exhaust gas turbine and compressor are usually fitted as one unit.
Turbocharger is divided into exhaust gas turbocharger, compound exhaust gas turbocharger and combined turbocharger according to the way of boosting. Their respective roles are as follows.
1. Exhaust gas turbocharger is the use of engine exhaust with a certain amount of energy into the turbine and expand to do work, the full power of the exhaust gas turbine for driving and turbine coaxial rotation of the compressor work impeller, in the compressor will be fresh air compression and then sent to the cylinder. The exhaust gas turbine and the compressor are usually mounted as one, it is called exhaust gas turbocharger. Its simple structure, reliable work, general diesel engine reasonably add exhaust gas turbocharging system, can improve power 30% to 50%, reduce than fuel consumption of about 5%, is conducive to improving the engine power performance, economic performance and emission quality, and thus widely used.
2. Composite exhaust gas turbocharger. Exhaust gas turbocharger is the exhaust gas power turbine and exhaust gas turbocharger working in series, known as a composite exhaust gas turbocharger. In some higher boost degree of diesel engines, exhaust gas energy in addition to drive the exhaust gas turbocharger, there is still excess energy for driving low-pressure exhaust gas power turbine, the power turbine through the gear transmission and hydraulic coupling and engine output shaft coupling. In this way, the exhaust gas turbocharger achieves the purpose of boosting pressure, while the exhaust gas power turbine converts the exhaust gas energy directly into power for the crankshaft. Composite exhaust gas turbocharger can make full use of exhaust gas energy, so that the power performance, economic performance greatly improved, but the structure is complex, high cost and technical difficulties.
3. Combined turbocharger. Combined turbocharger by the exhaust gas turbocharging and inertia boost combination. In the turbocharging system, in addition to the exhaust gas turbocharger, there is a stabilizer, resonance tube, resonance chamber and other components of the inertia boosting system, the use of pressure peaks can further improve the intake pressure after boosting. The system makes the diesel engine acceleration performance better and is beneficial to improve the low-speed torque of the diesel engine.
