Figure 2-30.  Cutaway view of airflow measuring section. moves the idle cutoff plunger inward against the release  lever in chamber A. The lever compresses the regulator  diaphragm spring to relieve all tension on the diaphragm  between chambers A and B. This permits fuel pressure plus  poppet valve spring force to close the poppet valve, stopping  the fuel flow. Placing the mixture control lever in idle cutoff  also positions the mixture control needle valve off its seat and  allows metering suction within the carburetor to bleed off. The fuel-injection system has many advantages over a  conventional carburetor system. There is less danger of  induction system icing, since the drop in temperature due  to fuel vaporization takes place in or near the cylinder.  Acceleration is also improved because of the positive action  of the injection system. In addition, fuel injection improves  fuel distribution. This reduces the overheating of individual  cylinders often caused by variation in mixture due to uneven  distribution. The fuel-injection system also gives better fuel  economy than a system in which the mixture to most cylinders  must be richer than necessary so that the cylinder with the  leanest mixture operates properly. Fuel-injection systems vary in their details of construction,  arrangement, and operation. The Bendix and Continental  fuel-injection systems are discussed in this section. They  are described to provide an understanding of the operating  principles involved. For the specific details of any one  system, consult the manufacturer’s instructions for the  equipment involved. section is shown in  Figure 2-30 . Movement of the throttle  valve causes a change in engine air consumption. This  results in a change in the air velocity in the venturi. When  airflow through the engine increases, the pressure on the left  of the diaphragm is lowered due to the drop in pressure at  the venturi throat.  [Figure 2-31]  As a result, the diaphragm  moves to the left, opening the ball valve. Contributing to this  force is the impact pressure that is picked up by the impact  tubes.  [Figure 2-32]  This pressure differential is referred  to as the “air metering force.” This force is accomplished  by channeling the impact and venturi suction pressures to  opposite sides of a diaphragm. The difference between these  two pressures becomes a usable force that is equal to the area  of the diaphragm times the pressure difference. The Bendix inline stem-type regulator injection system  (RSA) series consists of an injector, flow divider, and fuel  discharge nozzle. It is a continuous-flow system which  measures engine air consumption and uses airflow forces to  control fuel flow to the engine. The fuel distribution system  to the individual cylinders is obtained by the use of a fuel  flow divider and air bleed nozzles. The regulator section consists of a fuel diaphragm that  opposes the air metering force. Fuel inlet pressure is applied  to one side of the fuel diaphragm and metered fuel pressure  is applied to the other side. The differential pressure across  the fuel diaphragm is called the fuel metering force. The fuel  pressure shown on the ball side of the fuel diaphragm is the  pressure after the fuel has passed through the fuel strainer  and the manual mixture control rotary plate and is referred to  as metered fuel pressure. Fuel inlet pressure is applied to the  opposite side of the fuel diaphragm. The ball valve attached  to the fuel diaphragm controls the orifice opening and fuel  flow through the forces placed on it.  [Figure 2-33] The fuel injector assembly consists of: The distance the ball valve opens is determined by the  difference between the pressures acting on the diaphragms.  This difference in pressure is proportional to the airflow  through the injector. Thus, the volume of airflow determines  the rate of fuel flow. The airflow consumption of the engine is measured by  sensing impact pressure and venturi throat pressure in the  throttle body. These pressures are vented to the two sides of  an air diaphragm. A cutaway view of the airflow measuring  2-22 1.  An airflow section, 2.  A regulator section, and 3.  A fuel metering section. Some fuel injectors are  equipped with an automatic mixture control unit.  Airflow Section Fuel Injector Bendix/Precision Fuel-Injection System Regulator Section Fuel-Injection Systems