Patent GB-776552-A (GB)
Title: Improvements in and relating to dual fuel internal combustion engines
Inventor: MITCHELL ROBERT WESLEY STUART
IPC: F02D19/10
Filed: 1954-07-23
Abstract: 776,552. Regulating. ENGLISH ELECTRIC CO., Ltd. July 22, 1955 [July 23, 1954], No. 21566/54. Class 7 (6). In a control system for a dual fuel engine, the liquid fuel control and the gas supply control are resiliently coupled with the engine speed governor, with one another, and with the air supply control, the air supply being adjusted according to the fuel supply and the total supply of gaseous and liquid fuel being limited to prevent any excessive overloading of the engine. The governor G is connected to a floating lever 30 connected at one end 31 by a resilient link 33 to a lever 1 controlling the liquid fuel control means 24 and at the other end by a link 29, lever 28, resilient link 6 and lever 7 to a rotatable shaft 8 which controls the gas supply control means 18. The shaft 8 is also resiliently coupled to a lever 9 controlling the air supply control means 13 through a link 10 and floating lever 11 pivoted at 5" on a link 5 which is adjusted conjointly with the liquid fuel control lever 1 through a link 2 connected to a lever 3 on a sleeve 14 surrounding the shaft 8 and carrying a lever 4 connected to the link 5. A manual control lever 20, moving over a sector 23 and held in position by a spring catch 22, is coupled with lost motion to the liquid fuel control means 24 and carries a pin 25 engaging in a cam slot in a stop plate 26 which limits the movement of the lever 28. In moving from the lowest "stop" position of lever 20 to a mid-position on sector 23, the pin 25 moves over the lower position of the slot in plate 26 to hold the plate in a position in which the lever 28 is prevented from moving and the gas control valve is closed so that the engine operates on liquid fuel alone. On an increase in load the governor G moves the lever 30 about its connection to the link 29 causing the link 33 to move the lever 1 to increase the liquid fuel supply and, through the linkage 2, 3, 4 and 5, to open the air throttle valve. When the lever 20 is raised beyond the mid-position, for operation on gas, the pin 25, moving in the upper part of the cam slot, rotates the plate 26 to permit movement of the lever 28. The link 33 and liquid fuel control lever 1 are automatically moved by a resilient means similar to that described in Specification 712,365 to a position permitting only pilot injection of liquid fuel and the governor G on increase in load causes the lever 30 to rotate about its pivot point 31 to increase the gas supply through the linkage 29, 28, 6, 7 and 8 up to the limit permitted by the plate 26, the air supply being correspondingly controlled from the shaft 8 through the linkage 9 ... 13. If the increase of the gas supply to the maximum permitted for a given position of lever 20 is insufficient to deal with the increase in load, the lever 30 pivots about the link 29 and moves the liquid fuel control lever 1 to increase the fuel supply to supplement the gas supply, the linkage 2 ... 5 causing a corresponding opening of the air throttle valve 13. At the maximum permitted load the lever 28 is held against a stop C and the air throttle valve 13 is held against its wide open stop; any further increase in load causes the lever 30 to move the lever 1 to increase the liquid fuel supply, the linkage 2 ... 5 simultaneously moving the linkage 11 ... 8 to reduce the gas supply to prevent an overload. If it is desired to operate as a diesel engine on liquid fuel only the lever 20 is moved into its full-load position to open the air throttle valve fully, the gas supply being cut off by independent control means.