GB1010462A - Engine analyzer - Google Patents

Abstract

1,010,462. Electric tests. SOCONY MOBIL OIL CO Inc. [May 2,1962], No. 16875/62. Heading G1U. [Also in Division H4] Signals indicative of various operating conditions of each cylinder of a multi-cylinder engine are displayed as transverse deflections of respective lines of a horizontal line raster on a cathoderay oscilloscope the horizontal and vertical sweep deflections of which are synchronized with the rotation of the engine crank-shaft. The operating conditions considered are, cylinder pressure, timing of ignition or, when the engine is of the Diesel type, timing of fuel injection. The cylinder pressure indicative signals are produced by pressure operated switches 45 (Fig. 1) the working pressures of which as read on a gauge 49 may be adjusted by a valve 48 controlling a pneumatic or hydraulic supply line. During each piston stroke the associated switch 45 closes for a short interval and thereby generates a rectangular pulse which is supplied to the vertical deflection amplifier (see also Fig. 4) and thence to the vertical deflection plates 14 of the tube 11. Fuel injection indicative signals are generated by vibration sensitive devices (40 of the crystal or ceramic type) clamped to the fuel injection lines for each cylinder and when the engine utilizes sparking plugs signals indicative of ignition timing are derived via probes 81 adjacent the sparking plugs 82. Either of the latter signals may be selected by a switch E and supplied via amplifier 41 to the vertical deflection amplifier 17. The horizontal sweep of the tube 11 which is produced by sweep generator 18 and supplied to the horizontal deflection plates 15 via amplifier 19 is synchronized by pulses produced by an electromagnetic device 21 comprising a rotary member 23 driven by the engine crank-shaft and producing one pulse P2 for each cylinder such pulses occurring when the associated piston is (for a four cylinder engine) 45 degrees in advance of top dead-centre. This allows each raster line to represent 90 degrees of crank angle with the centre of each line corresponding to the top dead-centre position of the associated piston. When the engine has eight cylinders the horizontal synchronizing pulses are produced at instants corresponding to 22. 5 degrees in advance of top dead-centre and each line then represents 45 degrees of crank angle. For synchronizing the vertical sweep generator 16 an electromagnetic device 30 comprising a rotary member 31 driven by the crank-shaft and producing one pulse, coinciding with one of the horizontal synchronizing pulses, for each complete cycle of the latter pulses may be employed. Alternatively, by operation of switch 65 vertical synchronization may be effected by the reset pulses of a counter 67 which divides signals derived from the horizontal deflection amplifier 19 by factors (e.g. 2, 4, 8, 16) appropriate to the number of horizontal raster lines required. Fig. 2, shows the display produced in respect of an eight cylinder engine each line indicating, from left to right, the occurrence of ignition or of fuel injection followed by a rectangular pulse indicative of cylinder pressure. To facilitate visual checking of the alignment of the various lines marker pips which occur for each five degrees of crank rotation are displayed on the first and last lines of the display. These pipes are produced by an electromagnetic device 55 and supplied to the vertical deflection amplifier via amplifier 41. Additionally, by thus identifying the first and last traces the trace corresponding to a particular cylinder may be identified. If the trace corresponding to the first cylinder is not at the top of the raster it may be made to occupy such position by injecting one or more additional pulses into the horizontal synchronizing circuit by operation of a push-button switch 71. When the raster is to be photographed two or more successive engine cycles may be displayed by selecting a suitable stage of the counter 67 by means of switch 69. Specification 730,779 is referred to.