Page 208 - 05. Subyek Teknik Mesin - Automobile Mechanical and Electrical Systems Automotive Technology Vehicle Maintenance and Repair (Vehicle Maintenance Repr Nv2) by Tom Denton

2
192 Automobile mechanical and electrical systems

Figure 2.225 Mechanical fuel pump

Figure 2.226 Single-choke (left) and twin-choke (middle and right) carburettors

Figure 2.227 Fixed-choke (left) and variable-choke (right) carburettors

Key fact The function of the carburettor is to meter a quantity of petrol into the air stream
entering the engine cylinders. As the pistons move down in the cylinders on the
The function of the carburettor is to
meter a quantity of petrol into the air induction stroke the pressure in the space above the cylinders falls. On naturally
stream entering the engine cylinders. aspirated engines, that is, those that are not fi tted with pressure chargers,
atmospheric pressure provides the force for the air fl ow into the cylinders.
The greater the difference in pressure, the greater will be the volume of air that
enters the engine and the speed of the air fl ow through the carburettor and inlet