GB812862A - Improved multi-cylinder internal combustion engine - Google Patents

Abstract

812,862. Regulating; spray carburetters. GENERAL MOTORS CORPORATION. Aug. 19, 1957 [Sept. 10, 1956], No. 26083/57. Classes 7(3) and 7(6) In a multicylinder engine which operaates at part load on less than the maximum number of cylinders, the fuel supply is switched from one group of cylinders to another, either repeatedly or on successive operations at part load, so that any one cylinder is not continuously operative. In Fig. 6 two groups of four cylinders are fed with fuel from a metering device 59 with a metering chamber 61 connected through passage 72, 73, to pipes 86, 87 leading to distributers 88, 89, feeding the cylinders in each group, the metering chamber 61 having a by-pass valve 58 which is controlled in accordance with air flow in the induction pipe so that less fuel is by-passed back to the pump inlet 69 as the air flow increases. The passages 72, 73, contain shut-off valves 77, 78 which when pulled down by solenoids 93, 94, bypass the fuel from the pipes 72, 73, back to the pump inlet to put one or other of the cylinder groups out of operation. At idling, Fig. 7a, all cylinders are in operation but when the accelerator pedal 102 is depressed a predetermined amount, Fig. 7b, contacts 112, 113, are closed to energize one of the solenoids, e.g. 93, Figs. 6 and 8, to put one group of cylinders out of operation, and to energize a solenoid 111 which shifts a rod 104, carrying the pivot of a link 99, to the left to further open throttle valve 27 a predetermined amount which increases the air flow and produces an increased fuel supply to the four cylinders in operation. A sequential switch 117, Fig. 8, ensures that the current is supplied alternately to the solenoids 93, 94, so that the engine does not always operate on the same group of cylinders at part load; the frequency of alternation may be rapid or each time the engine changes from eight to four cylinder operation. Further depression of the accelerator pedal opens the throttle valve fully with the contacts 112. 113 still closed so that maximum torque on four cylinder operation is obtained. On still further depression of the pedal 102, contacts 112, 113 are broken, Fig. 7c, so that solenoids 93 and 111 are de-energized, permitting valve 79, Fig. 6, to rise to restore the fuel supply to its associated group of cylinders and releasing-shaft 104 so that the throttle valve 27 closes slightly to give the same torque from eight cylinders as was previously obtained from four. Further movement of the accelerator pedal opens the throttle valve fully for maximum torque from all cylinders. The pivot of link 99, Fig. 7, moves between stops 106, 107, of which the stop 106 may be adjusted by a centrifugal governor. A thermally operated switch prevents the operation of the solenoids 111, 93 and 94 at low temperatures. The metering bypass valve 58 is controlled by a diaphragm 41 controlled by the pressure drop in a venturi 31 in the intake pipe. The fuel from the metering device 59 is delivered to nozzles 26 situated adjacent the air intake valves 21.