GB1471537A - Engine valve control - Google Patents

Abstract

1471537 Controlling valve timing in IC engines R E VENARD 6 Dec 1974 [6 Sept 1973] 42001/73 Heading FIB [Also in Division G3] The timing of electromagnetically-actuated inlet or exhaust valves of I.C. engine cylinders is controlled by a programme which is operated according to a signal representing the value of various engine operating parameters e.g. engine speed, engine load, manifold pressure, throttle opening, ignition setting, exhaust gas condition, engine efficiency and engine power. A disc 1 with 360 spaced features 2 is connected to an engine crankshaft to rotate at ¢ crank-shaft speed. A transducer 3 detects the passage of features 2 and supplies a signal via a pulse shaper 9 to a pair of counters 12, 13. A feature 7 is detected by a transducer 5 at position 1, corresponding to top dead centre of one engine cylinder, and triggers a multi-vibrator 15 to signal a 3 millisecond counting time at counter 12 thus to form a 4-bit word indicative of crank-shaft speed. A feature 8, 30 degrees before top dead centre, generates a signal from transducer 6 to update the outputs of counter 12 and to reset counter 12. The counter 13 forms a 9-bit word indicative of instantaneous crank-shaft position and is reset by the signal from the transducer 5, as are outputs 26, 27. These outputs 26, 27 are supplied with data from inputs, 18, 19, 20, 21 concerning the engine operating parameters previously mentioned, which data is processed to form two 3-bit words at outputs 26, 27. These 3-bit words, together with the 4-bit word representing crank-shaft speed are addressed to read-only memories, 28, 29 for respectively generating 9-bit words for triggering opening and closing an engine valve, which are addressed firstly to data selectors 32, 33. Data for starting, braking or cruising is stored at 34 and supplied as 9-bit words to the data selectors 32, 33 which select data depending upon commands 35, 36 either from data store 34 or from read-only memories 28, 29. The selected data passes via outputs 37, 38 to comparators 39, 40 where it is compared with the 9-bit word from counter 13 indicative of instantaneous crank-shaft position. When this 9-bit word is the same as the selected data, a command signal is given to lines 45 or 46 to open or close an engine valve. The valve opening circuit may also include a loop 49, 50, 51, 52, 53, 54 to control the speed at which an inlet valve opens. Valve construction. A poppet valve 74 has a sleeve 72 at the end of its stem 73 into which sleeve protrude two armature ends 70, 71 of a pair of electromagnets 64, 65 having coils 62 to effect opening and coils 63 to effect closing of the valve 74.