Patent GB-632920-A (GB)
Title: Improvements in or relating to internal combustion engines
IPC: F02B43/00
Filed: 1945-10-05
Abstract: 632,920. Starting; engine-turning gear ; regulating; two-stroke engines. TOWNSHEND, E. F. R. Oct. 5, 1945, No. 25958. [Classes 7 (ii), 7 (v) and 7 (vi)] A two-stroke engine, which is capable of starting under a load and may be used directly coupled to the driving wheels of a train locomotive has a valve 86 for introducing compressed air into the cylinder 60 and a fuel injection and igniting valve 61 which may be constructed according to Specification 527,612. From starting to running the engine passes through three conditions viz. starting, boosting and normal running. Considering the engine, which may be using gaseous fuel contained under pressure in the bottle 156, to be at rest with its piston just beyond top dead centre, the valve 163 is opened to permit the flow of fuel to the jet 61, the valves 95 and 96 are opened to permit compressed air from the reservoir 92 to reach the valve 86 and a switch 73 is set to the start position. Current then flows through the switch 90 and cam switch 88 so energising an electro magnetic clutch 98 on the fuel metering motor system 91, 97 and 157 and the solenoid on the hydraulic valve 87, so opening the valve 86 and permitting compressed air to flow to the cylinder. When a predetermined quantity of air has flowed into the cylinder, the projection 99 on the clutch 98 moves the switch arm 100 in a clockwise direction thus breaking the switch 90 which stops the air flow and permits the clutch 98 to return to zero under the influence of a spring, and the switch 74 is made. Current now flows through the solenoid 65 via the timing cam switches 160 and 66 so that the fuel injector 61 is opened and fuel is admitted to and ignited in the cylinder 60. The piston is now in motion and the pressure in the cylinder is controlled by the piston 75 which is acting against the spring 78 and pressure in the container 77 and a connection between the piston 75 and injector 61, hydraulic as shown, reduces the flow of fuel if the pressure in the cylinder exceeds a predetermined value. Injection of fuel continues until the cam switches 66 and 160 are opened. At the end of the stroke the gases exhaust through the ports 111 and non-return valve 114 to the chamber 115 and then through the turbo supercharger 116 thus accelerating it. The pump 122 then scavenges the cylinder to the atmosphere through non-return valve 125 and ports 112 and the next cycle commences. When the locomotive has reached a speed of about 5 to 10 miles per hour, the boosting cycle is brought into operation by changing the switch 73 over to the run position. closing the valve 95 and opening the valve 108. The valve 86 is now timed to open for a short period late in the compression stroke by a cam switch 109 to admit compressed air through a pressure reducing valve 106 any excess air introduced at low speed being displaced by the piston into a pressure-equalising chamber 107. To change over from boosting to normal running, the switch 110 is opened and the switch 139 is closed, causing the valve 86 to remain closed and the air valve 135 to be brought into operation. Normal supercharging now takes place, the charge being supplied by the exhaust turbo blower 116, 133 through the valve 135 and ports 'scavenge air being supplied normally by the pump 122. If the running speed is now decreased, such as by a gradient, supercharging becomes excessive and this is counteracted by water injection through the nozzle 147 which is controlled by the pressure in the chamber 141 opened to the cylinder by the valve 143 at the completion of the supercharging. The pressure in the chamber 141 varies the size of the orifice in the metering device 145 and thus varies the quantity of water injected. The air reservoirs 92 and 105 may be charged during running by opening the valves 131 and 140 and closing the valve 130 so that the turbo supercharger supplies both scavenging and supercharging air and the pumps 122 and 128 act as a two-stage compressor. Reversal of the engine is effected by altering the position of the timing gear brushes 70 and 72. Specification 632,979 also is referred to.