Patent GB-401260-A (GB)
Title: Improvements in or relating to diesel locomotives having pneumatic transmission systems
IPC: B61C9/22
Filed: 1932-02-05
Abstract: 401,260. Compressing air. SOC. ANON. BREVETTI ZARLATTI, 11, Via Tibullo, Rome. Feb. 5, 1932, No. 3522. Void [Abridged as open to inspection under Sect. 91 of the Acts, Feb. 7, 1932]. [Class 8 (i).] In a Diesel-engine locomotive with pneumatic transmission system the controlling devices for the engine-compressor set are independent of the regulator valve control of the fluid to the locomotive cylinders and are grouped together in a unit so as to be operated by a single handle or the like. Thus the driver has only two controlling handles to operate, and these two may be combined. The engine-compressor controls comprise means for regulating the engine speed, altering the action of the compressor, and the admission of water or steam to the compressed air. In the construction shown a control handle 1 rotates a shaft 2 carrying cams 41 .. 4<1111>, Figs. 2 and 3, for acting on the compressor (not shown) and a cam 17, Figs. 2 and 4, controlling the engine speed. The cam 17 acts by means of a roller 18 on the springs of a centrifugal governor 21, this governor controlling the fuel valve of the engine by means of a lever 23, so that the engine speed varies in accordance with the movements of the roller 18. The cams 41 .. 4<1111> act in succession on valves 8, each of which can admit compressed air from the main tank 10 through a pipe 9<1>, valve-box 9, and pipe 11 to a chamber 12 containing a piston 13 acting on one of the suction valves 16 of the compressor. Only one suction valve and its associated parts are shown, but there are the same number of valves 8, pipes 11, &c., as there are suction valves. The control handle 1 has nine positions, marked in Figs. 3 and 4, and indicated by Roman numerals in Fig. 1. Position II corresponds to full power, all the suction valves being operative and the cam 17 in a position corresponding to full engine speed, say 480 r.p.m. Half-power is obtained in either of positions II and III ; in II the engine is at half-speed but all four suction valves are operative, in III the engine speed is increased to 320 but one suction valve is put out of action by its cam 4<1>. Other powers are obtained i as indicated in Fig. 1. The handle 1 is so operated by the driver as to keep the pressure in the tank 10 as constant as possible, a pressure gauge being provided. The handle may instead be operated automatically in accordance with the pressure in the tank, a servo-motor or relay being provided for this purpose. Admission of water or steam to the compressed air in the tank 10 is controlled by a device similar to the cams 4<1> .. 4<1111> and the valves 8, water or steam being admitted in accordance with the load requirements. The working fluid passes from the tank 10 to the locomotive cylinders through a regulator valve 24 which may be controlled by a separate handle or by the shaft 2. If it is controlled by the shaft 2 the handle 1 has a tenth position X in which the regulator valve is completely closed. If it is desired to move the control handle 1 and the regulator valve through a comparatively small angle (say, 90‹ to 120‹) while rotating the cams 4<1> .. 4<1111> and 17 through 360‹, the cams may be mounted on shafts geared to the control shaft 2 with the necessary gear ratio. Similarly, if desired, the cam 17 may be of helical form and may make more than one revolution. The cams 41 .. 4<1111> and valves 8 may be replaced by a single rotary valve which admits air to the pipes 11 in the required successive order. The cam 17 may be arranged to act directly on the fuel valve of the engine to alter the engine speed, the governor 21 being then simply operative to prevent excessive engine speed. The output of the compressor may be controlled in any other usual way instead of by acting on the suction valves as described above, thus the suction conduits may be throttled, or the delivery valves may be lifted during the suction stroke.