| 摘要 |
1,254,486. Electrical speedometers. DR-ING H.C.F. PORSCHE K.G, April 8, 1969 [April 6, 1968], No. 17835/69. Heading G1N. An electrical speedometer for an I.C. engine, energized by pulses picked up from the ignition unit, incorporates a maximum speed indicator. As shown, Fig. 1, pulses derived from the ignition coil 7 at a frequency proportional to the engine speed, are shaped at 2, integrated at 3 and fed via amplifier 9 to servomotor 8 which drives a pointer 11 through gearing 10 to indicate the speed. The battery voltage is fed to a converter 4 to give a stabilized output voltage which is tapped by servomotor 8 to provide a feedback voltage to amplifier 9. The motor 8 also drives a maximum speed indicator 24 through a ratchet arrangement, releasable by a spring-loaded button. The speed voltage signal at 3 is compared at 29 with a predetermined limiting value to switch off the engine at 30, if this speed is exceeded. |
