Patent GB-1196312-A (GB)
Title: Improvements in or relating to Engine Analyzer Systems
IPC: G01R13/20
Filed: 1967-06-21
Abstract: 1,196,312. Cathode-ray tube displays. BETA CORP. 21 June, 1967 [28 June, 1966], No. 28753/67. Heading H4T. In a piston engine analyzer system a signal from a transducer responsive to the parameter being investigated e.g. cylinder pressure, vibration and ignition information, is utilized to effect vertical deflection of the beam of a cathode-ray display tube against a time-base which is triggered by the output of a counter, when full count is reached, a count related to the angular position of (the piston in) the cylinder under test relative to the top deadcentre position of a master cylinder being set up initially at the start of each cycle of the engine and the counter then being advanced at a known rate during each engine cycle. Additionally, pulses derived when the counter has reached a predetermined count may be employed to blank (or intensify) the beam or to produce an additional vertical deflection to provide calibration markers indicating a particular angular position relative to top dead-centre. In Fig. 1, which shows the general scheme, a magnetic pulse generator (also Fig. 2, not shown) driven by the engine crank-shaft produces electric pulses, either at the rotational rate of the crank-shaft (terminal 20) or at onehalf this rate (terminal 18) the outputs being selected by switch 16 with the former utilized in the case of two cycle engines and the latter in the case of four cycle engines. The selected output on line 22, consisting of a pulse at each occurrence of the top dead-centre position of the master cylinder, is then utilized via manually adjustable switches SW1, SW2, SW3 (also Fig. 4, not shown) to set-up in a counter 70, initially containing zero count, a count related to the angular position of the (piston in) the cylinder under test relative to the top dead-centre position of the master cylinder. Coincidentally with this operation the counter is advanced by clock pulses from a source 50 comprising an electro-optical pulse generator (Fig. 3, not shown) driven by the engine and producing 360 pulses for each revolution of the crank-shaft, until a full count is reached, at which an output pulse from the counter derived via a diode gate 82 and switch 90, triggers the horizontal time-base via terminal 98a and after shaping in shaper 94, resets the counter to zero. The latter two operations occur either at a count of 360 or of 720, the former control being derived via switch 90 and terminal 92 of the diode gate 82 in the case of a two cycle engine and the latter via terminal 88 in the case of a four cycle engine switch 16 being at contacts 20 or 18 respectively. The time base is thus triggered at the top deadcentre of the cylinder under test and signals indicative of the parameter being investigated which are derived via an appropriate transducer 100 are supplied to the vertical input 98b of the display tube 98 via a mixer 101. For indicating a predetermined angular position relative to top dead-centre switches SW4, SW5, SW6 are set to indicate the desired number of degrees and when the count in counter 70 becomes equal to this number a pulse, produced at terminal 80, is applied to the vertical input 98b via mixer 101 to provide a marker. Alternatively the pulse may be utilized to blank (or intensify) the tube beam. When it is not practicable to employ the electro-optical engine driven clock pulse generator an oscillator of adjustable frequency may be used, the frequency being adjusted until the pip, which application of the pulses on line 22 to the vertical input via line 180 and mixer 101 produces, coincides with the marker pip which the pulse at terminal 80 produces when switches SW4, SW5, SW6 are set to 360, switches SW1, SW2, SW6 at 000 and switches 16 and 90 on contacts 90 and 92 respectively (Fig. 6, not shown).