ENGINE 1.3 QUADRAJET (75PS) 64 3A.1.5.2 COMPONENTS 3A.1.5.2.1 VACUUM PUMP The CP1 pressure pump (1) is the radialjet type with three radial pistons (tot al capacity 0.567 cc) and is controlled by the camshaft by means of an oldham joint (2); there are no timing positions. STRUCTURE Each pumping unit consists of: Q a piston operated by a cam in one piece with the pump shaft; Q a plate-type intake valve; Q a ball delivery valve. Because the pressure pump must be fed at a pressure of at least 0.7 bar , the fuel system is equipped with an auxiliary fuel pump submerged in the tank. The maximum delivery pressure reaches 1400 bar. The pressure pump is lubricated and cooled by the fuel via special channels. 3A.1.5.2.2 INJECTORS The injectors are fitted on the cylinder head and controlled by the injection control unit. The injector may be divided into two sections: Q actuator/atomizer consisting of pressure rod (1), pin (2) and nozzle (3); Q control solenoid consisting of coil (4) and pilot valve (5). Injector operation is divided into three stages. REST POSTION, the coil (4) is deactivated and the shutter (6) is in the closed position to prevent fuel from being introduced into the cylinder Fc > Fa (Fc: due to line pressure acting on the control area (7) of the rod (1); Fa: due to line pressure acting on the feed volume (8). START OF INJECTION, the coil (4) is energized and causes the shutter (6) to rise. Control volume fuel (9) flows out towards return manifold (10) to bring about a pressure drop on control area (7). Simultaneously, the line pressure flowing through the intake duct (12) exercises a force Fa > Fc in the supply volume (8) to cause the pin (2) to ltif and allow fuel into the cylinders. END OF INJECTION, the coil (4) is deactivated and causes the shutter (6) to return to closed position. This rebalances the forces so that the pin (2) returns to the closed position and the injection ends. 1 2
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