A study of turbocharger and its applications

Abstract

Now that we're in the midst of another kind of energy crisis, the turbocharger is back. In the 1980s, it was difficult to escape the turbocharger. The twin energy crises of the 1970s forced automakers to produce cars that delivered better fuel economy. And that meant downsizing engines. By the 1980s, turbo technology was evolving and automakers installed them to boost the power of these smaller engines. But turbos promised more than just power—they promised fuel economy benefits too. They Increased power for an engine of the same size OR reduction in size for an engine with the same power output. Reduced specific fuel oil consumption - mechanical, thermal and scavenge efficiencies are improved due to less cylinders, greater air supply and use of exhaust gasses. Thermal loading is reduced due to shorter more efficient burning period for the fuel leading to less exacting cylinder conditions. The high-altitude performance of a turbocharged engine is significantly better. Because of the lower air pressure at high altitudes, the power loss of a naturally aspirated engine is considerable. In contrast, the performance of the turbine improves at altitude as a result of the greater pressure difference between the virtually constant pressure upstream of the turbine and the lower ambient pressure at outlet. The lower air density at the compressor inlet is largely equalized. Hence, the engine has barely any power loss. Because of reduced overall size, the sound-radiating outer surface of a turbo engine is smaller, it is therefore less noisy than a naturally aspirated engine with identical output. The turbocharger itself acts as an additional silencer.