GB750954A - Improvements in or relating to a method of starting a reciprocating piston internal combustion engine - Google Patents

Abstract

750,954. Fuel injection; starting; regulating. TEXACO DEVELOPMENT CORPORATION. Feb. 3, 1954 [Feb. 12, 1953], No. 3208/54. Classes 7(3), 7(5) and 7(6) General. In a method of starting an engine wherein a cyclically inducted air charge of constant size is caused to swirl about the combustion space 34, Fig. 2, and fuel is injected into a localized portion of the air at a given rate and period to form successive increments of fuelvapour-air mixture, and positive ignition is timed to occur in the first increment to produce a flame front 72 for progressive combustion of remaining mixture, the ratio of vaporized fuel to air is temporarily increased in the mixture increment which is initially subject to positive ignition. The inlet and exhaust valves 28 and 30 respectively are of the overhead type, the inlet valve having a semi-cylindrical shroud 36, Fig. 1. that causes the incoming air to swirl within the disc-shaped combustion space 34 at between four to eight times the engine speed. The compression ratio may be 10-12:1. Fuel injection. The fuel injection nozzle 40 is directed tangentially of the chamber 34 and sprays a conical fuel-jet downstream of the swirling air, the spray being generally perpendicular to the cylinder axis and on a chord of the chamber 34; the nozzle 40 which is of the pressure-actuated type is supplied with fuel by a jerk pump 44 operated in timed relation to the engine by a driving connection 52, the pump having a cam-driven plunger 46 with a by-pass helix 48 which determines the duration of the injection through rotation of the plunger 46 by a rack 50. The pump 44 supplies fuel to the nozzle from 70 degrees - 20 degrees crank angle degrees before T.D.C. and the rate of injection is co-ordinated with the air swirl rate to provide for impregnation of successive increments of air at a fuel-air weight-ratio of 0.06 - 0.08. Ignition system. The sparking plug 56, Fig. 2, is located 30 degrees - 60 degrees downstream of the nozzle 40 with the electrodes close to the' upper side of the fuel spray so that they are out of the direct path of the fuel particles; the plug is energized from a coil 58, Fig. 1, by operation of a circuit breaker 60, the rotor 62 of which is driven from the engine in timed relation thereto by a connection 64. The spark timing, which is altered by rotating the casing 68, is adjusted so that it is synchronized with the initiation of fuel injection, in order to ignite the first increment of mixture, the engine subsequently operating as disclosed in Specification 596,846. Starting and regulating. In order to ensure reliable starting when using fuels of low volatility or high viscosity, partcularly in low ambient-temperature conditions, any one of the following methods may be adopted. (1) Delaying the energization of the sparking plug relative to the commencement of fuel injection by rotating the casing 68; this may be effected by joining the casing to the fuel-pump rack 50 through a mechanical connection 74 so that the duration of fuel injection is increased as the ignition is retarded. (2) Delaying the energization of the sparking plug long enough to permit the air to complete at least one swirl and to begin another and, at the same time the duration of fuel injection may be increased to allow in the overlapped portion of the air stream another injection so that the overlapped portion is twice impregnated with fuel. (3) Increasing the fuel injected relative to the quantity of air supplied by means of a throttle valve 32 in the outlet pipe 26. Specification 596,846 is referred to.