A Fuel Injection System for Internal Combustion Engines

摘要

1,177,334. Fuel injectors; stopping engines. SOC. DES PROCEDES MODERNES D'INJECTION SOPROMI. March 21, 1968 [March 22, 1967], No. 13648/68. Headings F1B and F1K. In a fuel injector having an electromagnetically operated valve or valves 15, 19, in a return flow line 20 controlling the opening of the ejector valve 10, means are provided either in the fuel supply line 1 or in the return flow line 20 which upon faulty operation of the valve 10 either shut off the fuel flow or actuate an alarm means. In Fig. 1 fuel flows from the pipe 1 to the injector space 10 and supplies fuel flow through orifice 11 to chamber 12A and return pipe 20 via the two electromagnetic valves 15, 19, in series. When valves 15, 19, are closed, the valve 10A is held closed by the pressure in chamber 14, opening of the valves 15, 19, releasing said pressure and permitting valve 10 to open. A pressure gauge 27 is connected to the space 26 between valves 15, 19, and is associated with electrical contacts in an alarm system whereby the alarm is operated when the pressure in space 26 is higher or lower than normal caused by the valves 15, 19, sticking open or not opening. A second safety device 3 in the pipe 1 cuts off the flow to the injector if the valve 10 sticks open. The device 3 comprises a piston 4 by-passed by a passage 6 with a calibrated orifice 6a. Upon normal operation of valve 10 the piston 4 moves by less than its full travel on each injection cycle, the fuel for injection flowing through by-pass 6. If valve 10 sticks open the excessive fuel flow moves valve 4 to its extreme right position, blocking by-pass 6 and cutting off the fuel flow. The by-pass 6 may be replaced by an orifice through the piston. Valve 15 may be arranged to open slightly before valve 19, the resultant slight reduction in pressure in chamber 14 permitting valve 10 to open briefly for a pre-injection. In a modification Fig.2 (not shown) the device 3 is replaced by a spring-loaded piston (24) carrying electrical contacts which close upon an abnormal pressure drop in chamber (23) to actuate an alarm and cut off the fuel flow.