Patent GB-363891-A (GB)
Title: Improvements relating to fuel injection in oil engines
IPC: F02D1/00
Filed: 1931-02-16
Abstract: 363,891. Oil engines. PACKARD MOTOR CAR CO., Detroit, Michigan, U.S.A. Feb. 16, 1931, No. 4896. Convention date, April 2, 1930. [Classes 7 (ii), 7 (iii), 7 (v), and 7 (vi).] The plunger of a fuel-injection pump is operated at different speeds relative to the speed of rotation of the crank shaft by a pair of cams, the cam in use at the lower speed operating the pump plunger during normal running of the engine, and the cam in use at the higher speed operating the plunger during slow running of the engine. In a radial-cylinder four-stroke engine, fuel is fed by a low-pressure pump from a reservoir into a manifold 34 which is connected to fuel pumps associated with each cylinder. An overflow conduit 35 connected to the uppermost cylinder conducts excess fuel back to the reservoir. Fuel is drawn into pump barrels 30 when an inlet port 32 is uncovered by the plunger 31, and is forced by the plunger through a nozzle A after the plunger has closed the port 32. Each nozzle A and pump B are formed as an integral structure. To vary the length of the plunger stroke, each plunger bears on a spring-pressed member 36 and is actuated from a curved face 43 of a rocker lever 41 through a link 40 and a plungeractuating-rod 39. The link 40 is adjusted on the face 43 by turning a ring 44 to which is fixed a link 45 joined to the link 40. The ring 44 is moved by a rack and pinion 48 operated by a lever 49. The levers 41 are provided with lateral extensions 67, Fig. 2, so that they can be operated either by a single lobe 64 or by four lobes 59 on a cam 56. The lobe 64 is carried at one end of an arm 54 pivoted at 55 and carrying at the other end a weight 65 held against a casing 51 by a spring 66. The lobe 64 extends through a peripheral opening in a cam structure consisting of members 51, 52 attached to the crank shaft, and between which the arm 54 is pivoted. The cam 56 is rotatably mounted on an extension of the member 52 and is driven through reduction gearing 60 .. 63 at one-eighth crank shaft speed in the opposite direction to the crank shaft. During slow running (i.e. below 1400 r.p.m.), the cam lobe 64 is in the position shown in the full lines in Fig. 3, and actuates the levers 41. As this lobe 64 is rotated at crank shaft speed, it gives a faster injection stroke to the pump plunger than that given by the slow moving lobes 59. As the speed of revolution increases, the lobe 64 becomes ineffective,. centrifugal force withdrawing it into the cam structure, as shown by the dotted lines in Fig. 3, and then the cam lobes 59 actuate the levers 41. The lobe 64 is fixed on the crank shaft to lift the rocker levers before they contact with the lobes 59, thus causing the lobes 59 to pass under the levers ineffectively, and the lobes 59 are made so long that the levers ride on them after being raised by the lobe 64 so that the lobe 64 operates only every other rocker in each revolution. Between injection strokes, the rockers contact with a base circle 56 to allow the pumps to fill with oil. The cam lobe 64 has a gradually rising face to reduce shocks caused by the contact of the lobe with the rocker levers. Starting; valve gear; cylinder passages.- At starting, the engine is slowly rotated by applying an inertia starter to the crank shaft jaw 151. Four lobes 57 on the cam 56 actuate rocker levers 58 which, through valve rods 25, operate valves 21 in the cylinder head. These valves 21 control single passages 20 which serve for both air inlet and exhaust. The passages 20 are in the form of a Venturi tube and extend tangentially of the internal wall of the cylinder and at an angle to the axis thereof. Crank casings. -A partition 12 in a barrel crank case 11 separates the compartment 13 containing the connecting-rods from a compartment 14 containing the accessories. A rear cover 15 provided with apertures 16 enables the engine to be fixed to a suitable support.