GB1295973A - - Google Patents

Abstract

1295973 Determining timing angle SCANS ASSOCIATES Inc 30 July 1970 [2 Sept 1969] 37030/70 Headings G1U and U12A6 [Also in Divisions Fl and G3] The timing angle of an internal-combustion engine is determined by measuring digitally the time interval between the moment when the sparkplug of a selected cylinder fires and a predetermined position in the piston cycle of that cylinder. This is effected by counting pulses from an encoder 25, Fig. 6, driven by the engine crankshaft for the time between a pulse when a high voltage probe 21 detects the spark and a pulse on a magnetic pick-up 20 sensing a notch 18 in a crank-shaft vibration damper. The notch position is such that the pulse is produced when number 1 cylinder is at its top dead centre. The count may be compared with upper and lower pre-set limits either in digital comparators 40, 41 or after conversion to analogue form, in analogue comparators (42, 43,) Fig. 7, (not shown) to control delays 51, 52 via the contacts 54, 55 of which a servomechanism is operated to move a distributer adjustment lever 35 to correct the time angle. Conveyers bring engines to and from a loading and unloading bay to separate test stands Fig. 1, (not shown).