Tachometer without physical connection to internal combustion engine
US3978719A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 30, 1975 |
| Grant date | Sep 7, 1976 |
| Priority date | — |
| Expiry date | Apr 30, 1995 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D2200/1015
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A tachometer includes a transducer for sensing pressure variations at the end of the exhaust pipe, or other easily-accessible point, due to explosions in an internal combustion engine. The transducer produces a corresponding electrical signal having a prominent selected frequency component which varies in frequency in direct proportion with engine speed. As the engine speed is increased and decreased, the electrical signal is passed through an amplifier with automatic gain control, and through a tracking filter to separate the prominent frequency component from other components. The separated component may be applied to a frequency-measuring device calibrated to display the revolutions per minute of the engine, or to a computer which computes and displays the result of an acceleration burst test.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.