The Packard Diesel Engine: An Important Series of British Patents Covering Details of the Design
Aircraft Engineering and Aerospace Technology
Article publication date: 1 October 1932
In a nine‐cylinder radial compression‐ignition engine, a single venturi passage 15 which serves for the admission of air and the exhaust of each cylinder is controlled by a valve 17 opened through a pushrod 19, and fuel is discharged through a nozzle, Fig. 8, controlled by a spring‐loaded valve 30 held off its seat by a stop 33. Fuel for all the cylinders is circulated through a manifold 40 and is delivered to the pumps through ports 41. Fuel is trapped by a plunger 39 and forced past a pair of non‐return valves 38 and a passage 34 to its appropriate fuel nozzle. The plunger is withdrawn by a spring 42, its forcing stroke being effected by a link 44 which bears on a camactuated lever 50, 51, 52. The stroke of the plunger is adjusted by toothed gearing 47, 48 which rotates a ring 46 carrying links 45 pivoted to the links 44. The fuel‐pump actuating cam 54 has four lobes and is driven through gearing 59 . . 62 at one‐eighth the speed of the crank shaft; this cam also operates the cylinder valves 17. The pumps may also be driven by a cam 73 having a single lobe and rotating at the speed of the crank shaft to which it is keyed. The high‐speed single‐lobe cam is operative when starting and times the fuel injection to occur just before top dead‐centre whereas the cam 54 times the injection so that it occurs 40 deg. to 20 deg. before the top dead‐centre. The starting gear comprises a motor 24 having a sliding dog clutch 25 which engages jaws 77 on a sleeve 76 mounted in a second sleeve 75. The sleeves are held against relative axial movement, but are each provided with diametrically opposed inclined slots 78, 79, Fig. 7, which impart to them a relative rotational movement. A pin 80 projects through the two slots into grooves 81 at the end of the crank shaft, and a spring 82 in the hollow portion of the crank shaft bears against a carrier 83 through which the pin 80 projects. During normal running, when the cam 54 actuates the plungers, the spring 82 forces the carrier 83 and the pin 80 to extend the sleeves 75, 76 to their rearmost position. The lobes on the cams 73, 54 are so arranged relatively that the one which is effective will shield the other from the levers 50, 51, 52. At starting, the jaw 25 is moved into engagement with the jaw 77 and the pin SO moves in its axial groove 81 to rotate the sleeves 75, 76 without imparting rotation to the crank shaft. The rotation of the sleeve 75 places the cam 54 in a retarded position so that its cam lobes are ineffective and pass under the lobe on the cam 73. As a consequence the speed of the fuel injection is increased, and as the engine starts the crank shaft overruns the jaw 25 and the spring 82 forces the sleeves 75, 76 and the pin SO to their rearmost position to establish normal running. The shifting of the cam 54 retards the actuating cam lobe 70 of the air inlet valve so that at starting the closing of the air inlet valve is delayed to allow part of the air charge to escape.
(1932), "The Packard Diesel Engine: An Important Series of British Patents Covering Details of the Design", Aircraft Engineering and Aerospace Technology, Vol. 4 No. 10, pp. 267-267. https://doi.org/10.1108/eb029608
MCB UP Ltd
Copyright © 1932, MCB UP Limited