Today's trend in the automotive industry has been a shift from naturally aspirated engine to a turbocharged low volume . Using the turbo allows you to simultaneously solve a number of problems that meet the requirements of time : cardinality and significantly improve engine performance while reducing fuel consumption as compared to the naturally aspirated engine of the same capacity , to achieve high efficiency , together with other technical solutions to reduce emissions.
The obvious way to increase the capacity of any engine is to increase the burning of fuel in it and create optimal conditions for its combustion in various operating modes. Post a lot of fuel in the cylinder-piston engine at any point of his work is not a problem, but not so on the appropriate amount for the combustion air. Air is sucked into the engine during its operation due to the motion of the pistons in the cylinders and the amount can be considered relatively constant and independent of the v
To solve the problem of saturation of the engine with plenty of air used different technical solutions , but the most effective and fundamentally contributing to a significant increase in engine power, it has become turbocharged .
The principle of operation is very simple turbocharging.
- Part of exhaust gas admitted into an exhaust system is applied to the impeller, which spins under their action.
- On the same shaft with the impeller is an impeller of the compressor which compresses air and supplies it to the engine intake manifold.
- One conventional compressed air unit comprises more oxygen molecules than the same volume of air at atmospheric pressure. Consequently, a large number of molecules of oxygen can oxidize ( burn ) a greater amount of fuel in the cylinders and to obtain an increase in engine power .
- The more turns, which develops under the effect of exhaust gas from the impeller rotor, the more compressed air and the greater the amount of oxygen supplied to the cylinders. Turbocharger rotor speed in modern engines can reach 250,000 rpm. Rotating rotor bearings in an oil film. This implies increased requirements for turbocharged engines as a lubricant. It should be only a second to break the lubrication conditions and the instantaneous failure of the costly assembly are guaranteed.
- Another disadvantage is the so -called turbo " turboyamu ". To unleash the turbine rotor necessary engine speed of 1500-2000 rpm . Until the specified quantity turbine hardly works and the difference in engine power between the two modes , usually quite palpable. In modern engines, various auxiliary systems learned to neutralize this effect and make it virtually invisible .
- Due to physical laws during air compression vane turbocharger compressor is its heat. And as is known , it is accompanied by heating of the air expansion , and consequently reducing the amount of oxygen per unit volume of air. To avoid this backlash in some cases resorting to the use of charge air cooling in a special device - intercooler .
- Besides the " classical" turbochargers working on the energy of exhaust gases , in some cases, a similar device is used with a mechanical drive . A significant disadvantage of such solutions is that it must work for a number of selected engine power.