The concept of increasing the fuel efficiency of a petrol engine in this project, is to pre-heat the intake air which is flowing through the carburetor.  The humidity in the atmospheric air affects the petrol vapourisation in the carburettor.  Therefore, by pre-heating the inlet air to the carburettor for a considerable amount, the vapourisation can be ease and in turn complete combustion is achieved.  Moreover by reducing the water vapour to the engine, the steam formation in the engine can be reduced pitting of the engine cylinder, piston and exhaust pipe.


The pre-heating of inlet air to the engine can be achieved by fixing a heat exchanger inside the exhaust pipe.  The atmospheric air is sucked through the heat exchanger to the carburettor.  The air which is flowing though the heat exchanger gets heated by the engine exhaust gas.




An air preheater (APH) is a general term to describe any device designed to exhaust heat air before another process (for example, combustionin a petrol engine ) with the primary objective of increasing the thermal efficiency of the process. They may be used alone or to replace arecuperative heat system or to replace aexhast pipe..


The purpose of the air preheater is to recover the heat from the exhast which increases the thermal efficiency of the petrol engine  by reducing the useful heat lost in the exhaust   gas. As a consequence, the exhaust  gases are also conveyed to exhaust pipe


The heat exchanger is located in the engine exhaust pipe.  The exhaust pipe consists of a muffler and stay plates etc.  The heat exchanger is made up of 18 Gauge  EN8. plate. The inner tube is inserted tightly on the muffler tube.  A baffle plate pipe  arrangement is made in between the two conic tubes so as to make a spiral path to the incoming air.  So that the heat transfer to the air can be increased.  Moreover the air is flowing in counter direction to the exhaust gas; thereby effective heat transfer can be achieved.


The heat exchanger inlet is fitted with a pre-filter.  The outlet is connected to a by-pass mechanism through a hose pipe.  The by-pass mechanism is connected to the carburettor intake. The temperature of the air entering to the carburettor can be maintained constant for a particular degree centigrade.  allows the atmospheric air to mix with the heater air from the heat exchanger.  So the hot air is diluted with atmospheric air and reducing the temperature. So increasing fuel efficiency of the petrol enigine system





  • Getting more power to the vehicle
  • Easy to fitting and removing
  • Low cast



Fitting on two wheeler take more space




  • It applicable in all automobile vehicles