Patent GB-1292628-A (GB)
Title: Fuel injection system
IPC: F04B49/24
Filed: 1969-11-10
Abstract: 1292628 Fuel-injection pumps; regulating IC engine fuel supply; fuel injectors BORG WARNER CORP 10 Nov 1969 [23 Dec 1968 11 Sept 1969] 54887/69 Headings F1A and F1B A reciprocatingor rotary fuel-injection pump for supplying fuel or fuel and lubricating oil mixture, to the air intake manifold of a twostroke IC engine has its output varied in accordance with engine speed by a spring-loaded check valve responsive to the pressure impulses in the pumping chamber to by-pass an increasing amount of fuel with increasing engine speed, thereby lessening the tendency for the fuel-air ratio to increase as engine speed increases due to decrease in engine load conditions. In Fig.8, check valve 163 has its spring-loading adjustable by a shaft 131 which also controls the pump output by rotating piston 130, via gears 83, 84, in its cylinder 129a to control the timing of opening and closing of oil inlet and outlet ports 134, 135 and fuel inlet and outlet ports 136, 137 by piston grooves 138, 139 communicating with oil and fuel pumping chambers 155 and 160, respectively. Control shaft 131 may be rotated by the engine throttle control, Fig.5b (not shown), incorporating a choke control to provide increased fuel for starting. Alternatively, shaft 131 may be automatically controlled by crank-case pressure acting on a diaphragm Fig.3e (not shown). The oil and fuel are delivered via flexible "duckbill" valves 150, 151 and a mixing chamber to the injection nozzle. Check valves may be provided in feed and return lines between an oil tank and oil inlet chamber 128 to keep the oil cool by circulation, and the oil tank may be pressurized by the engine crank-case, Fig.2 (not shown). Also in Fig. 2, the oil pumping chamber may deliver to the fuel pumping chamber through a check valve (76), and the oil piston may control a by-pass port (63) in the fuel pumping chamber, so that if the oil supply fails, fuel delivery is stopped. In Fig.3 (not shown), fuel is circulated between the fuel inlet chamber and the fuel tank for cooling. In Fig.4 (not shown), the pump is mounted on the engine crank-case and the piston is connected to a bearing ring (85) surrounding an eccentric on the crank-shaft. In Fig.8a (not shown), chamber 128 acts as the oil pumping chamber. In the rotary pump of Figs.9a and 9b, a rotary cam 227 comprises two approximately 180 degree portions of different radius, and is engaged by spring-loaded followers 235, 236 defining two pumping chambers between cam 227 and casing 234. During rotation of cam 227, fuel is drawn into and discharged from each chamber via cam inlet passage 228 and outlet passage 230, followers 235, 236 being rocked about their axes at each cam radius transition to engage the cam surface with either edge 235a or 235b. By-pass valve 241 connects outlet passage 230 to inlet 226, and may be sealed so as to be affected by inertia or centrifugal force, thereby regulating the fuel delivery according to engine acceleration or speed. Outlet port 231 sequentially registers with a pluarality of delivery and return ports in plates 225 and 232 engaging end faces of cam 227, Fig.9b, plate 232 being angularly adjustable to vary the delivery. In Fig. 9h (not shown), a by-pass valve (241a), (241b) for each pumping chamber is provided in casing 234, the loading on the valves being controlled by a control member acting through a scissors system to equalize the load on the valves. In Fig. 11 (not shown), a rotary distributer valve plate (370) is provided between cam 227 and control plate 232 and incorporates a by-pass valve loaded by a mass (375), Fig.11a (not shown). In Figs.12a to 12c (not shown), the rotary pump has the cam surfaces of different radius formed in the stationary casing, and the followers mounted in a cylindrical rotor. A fuel-injection nozzle, Fig. 6, comprises a resilient "duckbill" valve 218 connected to delivery pipe 215 and provided with a solid, cylindrical insert 217, e.g. of nylon, to produce a ring-shaped spray pattern, Fig.6a (not shown) For a twin cylinder engine, Fig. 7 (not shown), a single injector is directed at an apex in the air inlet manifold to provide even distribution.