Engine diagnosis from frequency components in exhaust
US3977239A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 2, 1976 |
| Grant date | Aug 31, 1976 |
| Priority date | — |
| Expiry date | Jan 2, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01M15/106
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An engine diagnostic apparatus includes a transducer for translating an exhaust pressure waveform emitted by an engine to a corresponding complex electrical signal having a prominent fundamental frequency component which represents the cylinder firing frequency and varies in direct proportion with engine speed, and having a subharmonic frequency component at a frequency which is a submultiple of the fundamental frequency. The subharmonic frequency component and the fundamental frequency component are separated from the complex electrical signal and from each other. A comparator compares the amplitude of the subharmonic frequency component with the amplitude of the fundamental frequency component to provide a measure of the unevenness of power strokes from individual cylinders of the engine.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.