GB808206A - Improvements in fuel injection systems for internal combustion engines - Google Patents

Abstract

808,206. Fuel injection systems. NYLANDS VERKSTED May 11, 1955 [May 11, 1954], No. 13658/55. Class 7(3) A spring-loaded fuel injection valve 4 is opened by fuel from a compressionpressure-operated fuel injection pump supplied through a passage 5 and any increase in the fuel pressure above the normal value required to open the valve 4 opens a spring - loaded needle valve' 25 leading to a pressure accumulator chamber 20, a plunger 18 in which is forced down to increase the spring loading of the valve 4 so that this valve opens later in the compression stroke on the next engine cycle; a bleed 28 permits gradual release of the excess pressure from chamber 20. The plunger 18 is normally held against an adjustable stop 21 by a spring 15 which acts on an abutment rod 13 in contact with the top 8 of the valve 4, which valve is normally loaded by the spring 15 and by a spring 9 in contact with a slidable abutment 10 adjusted by a screw 12. During a normal engine cycle the valve 25 does not open. If abnormal compression pressures in the engine cylinder produce abnormally high fuel pressures in the passage 5 the valve 25 opens and the plunger 18 is forced down to increase the load of the spring 15, whereby a higher fuel pressure is necessary to open the valve 4 on the next cycle and the opening is delayed, producing a lower compression pressure in the engine cylinder and tending to restore the engine compression pressure and hence the fuel pressure back to normal. The pressure in the space 20 is slowly reduced back to normal, permitting the plunger 18 to return to its stop 21, by bleed passage 28 controlled by an adjustable needle 29, which may be manually or automatically adjusted. In a modification the pressure in chamber 20 acts directly on the abutment disc 16 which is sealed to the wall of chamber 20 by a bellows; alternatively the spring 15 may be replaced by a spring-loaded diaphragm closing the chamber 20.