Anglicky v odborných předmětech "Support of teaching technical subjects in English “

1. Anglicky v odborných předmětech"Support ofteachingtechnicalsubjects in English“ Tutorial: Physics Topic: Turbosupercharger Prepared by : RNDr. Ondřej Jeřábek Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/04.0002 je spolufinancován Evropským sociálním fondem a státním rozpočtem České republiky.

2. Turbosupercharger

3. Turbosupercharger General information: • Type of pump used to gas pumping • Developed for air craft engines – lack of air in high altitude • Used mainly at combustion engines – increasing efficiency Advantages and disadvantages: • Main advantage is increased efficiency at minimal weight increase • Main disadvantage is increase of compression ratio and susceptibility to self-ignition

4. Turbosuperchargerprinciple • Turbosupercharger is driven by exhaust gases • Supercharger blasts and pushes air inside cylinder • Exhaust and supercharger turbines are fit on the same shaft • Turbosupercharger´s efficiency is about 80% • Turbosupercharger of engine 1.2 TSI works in range of 1500 revolutions/min. - 3500 rev./min. • For increasing of revolutions´ range, there is variable blades´ geometry of turbosuperchargers one by one

6. Cooling • Turbosupercharger cooling • Turbosupercharger is cooled by engine oil • For sufficient turbosupercharger cooling , it is important to provide continuous circuit of engine oil • It is important to let turbosuperchargers cool for 2 minutes before stopping the car • Compressed air cooling • Compressed air heats up on the way to valve • This problem eliminates Intercooler

7. Turbosuperchargerconstruction • Turbosupercharger rotates very quickly – 10 000 to 300 000 rev./min • Such quick revolutions could be the problem for common ball bearings which could explode • That is why there are used fluid bearings in which are moving parts separated and they are cooled by thin cover of engine oil • EGR valve protects turbosupercharger´s damage when braking by engine • Excessive air is blown back to suction

8. Turbosupercharger reliability • Intake air must be clean • Exhaust gases must be without stationary parts • After driving at high power output, engine must go for 2 minutes before switching off at idling and it enables turbosupercharger cooling • If it does not happen and engine is switched off, oil stops circulating and it remains in turbosupercharger where this oil can be burned • Overburnt oil can choke its supply and it can cause turbosupercharger damage

9. Turboeffect • It is the moment between depressing of gas pedal and beginning of engine reaction • Time between increasing of flammable mixture inside the cylinder and pressure increase on turbosupercharger blades • Unpleasant especially for co-driver • Turboeffect prevention • Some producers prefer 2 smaller turbosuperchargers to one big turbosupercharger (each works in different speed range) • At some petrol engines, there are advantages of mechanical compressor and turbosupercharger as well • Small compressor works only at low revolutions, at higher revolutions turbosupercharger takes over

10. Activity I • Explain the meaning of EGR valve

11. Activity II • Describe the meaning of turbosupercharger and focus on its advantage and disadvantage

12. Literature • JAN, Zdeněk; ŽDÁNSKÝ, Bronislav ; ČUPERA, Jiří . Automobily 1. Brno : Avid, 2004. 211 s. • JAN, Zdeněk; ŽDÁNSKÝ, Bronislav ; ČUPERA, Jiří . Automobily 2. Brno : Avid, 2004. 120 s. • JAN, Zdeněk; ŽDÁNSKÝ, Bronislav ; ČUPERA, Jiří . Automobily 3. Brno : Avid, 2004. 220 s. • JAN, Zdeněk; ŽDÁNSKÝ, Bronislav ; ČUPERA, Jiří . Automobily 4. Brno : Avid, 2004. 350 s. Translation: • www.seznam.cz • www.slovnik.cz • JANATA, Petr. Handy slovník technický anglicko-český a česko-anglický. Plzeň: Nakladatelství Fraus, 2000. ISBN 80-7238-075-3 • Lingea LEXIKON 5, Technický slovník anglicko-český a česko-anglický. 2010.