A carburettor is an important part of the Petrol engine. Image credit MediaWiki

A carburettor is an important part of the Petrol engine. Image credit MediaWiki

ZIMSEC O Level Combined Science Notes: The carburetor

  • A carburettor is an essential part of Petrol engines
  • A typical carburettor has the following parts:
  • An air filter- air is drawn into the engine via the air filter which cleams the air by removing dirty particles such as dust
  • Choke/Choke valve-controls the amount of air that is entering the engine
  • Closing the choke gives an air and petrol mixture that is richer in petrol and makes starting the engine easier
  • Petrol is pumped into the engine and enters the carburettor through jets
  • Jets-turns petrol into a fine mist spray in the chamber where air and petrol is mixed
  • Worn jets might be blocked by dirt particles
  • Petrol is filtered using a petrol filter  to remove dirt particles and thus prevent jets from being blocked
  • The air filter and jets must be cleaned, serviced and replaced regularly to allow the engine to function efficiently
  • The air and petrol mixture is introduced into cylinders where it is compressed, ignited by spark plugs and the resulting exhaust fumes expended through the outlet valve
  • Throttle-is controlled by the accelerator, it controls the amount of the petrol, air mixture that passes through into cylinders and in turn the speed of the engine
  • Particles in the air might also block jets
  • Jets have to be cleaned and replaced regularly

To access more topics go to the Combined Science Notes page.


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