In exhaust gas turbo charging, part of exhaust gas energy, which would normally be wasted is used to drive a turbine. The turbine shaft is connected to a compressor, which draws in combustion air, compresses it, and then supplies it to the engine. The increased air supply enables more fuel to be burnt; hence the engine develops higher power. Increased air availability improves combustion of fuel, thus leading to lower fuel consumption and less emission.Read less