| 摘要 |
1,106,200. Digital engine indicator. H. LIST. 21 Dec., 1965 [25 Jan., 1965], No. 54194/65. Heading G4H. The area of the pressure/travel curve of an internal-combustion engine is measured by apparatus including a pressure transducer 1 applying a proportional signal to a comparator 3 an electromagnetic pick-up 7 actuated at intervals proportional to piston travel to trigger a sawtooth generator 13 giving a second input to the comparator, pulses being gated into a counter 14 for the period before equality is reached. The head 7 senses magnetic marks on a disc 5 rotating with the engine shaft. The duration signal from comparator 3 represents the pressure in that particular strip of the curve. Pulses from an oscillator 16 are gated 15 to counter 14. The engine shaft also carries deadcentre marks 17 sensed by a second head 18 to produce four stroke pulses in each cycle. These pass to a 5- stage shift register 21, the first four stages of which control the counter 14 so that the counts produced during the first and third strokes are added and those produced in the second and fourth strokes are subtracted. The final contents of the counter give the area of the indicator diagram. Instead of using a reversible counter, two counters may be used, the values being subtracted afterwards. The apparatus may be designed to integrate more than one cycle. |
