Misfire detection in automobile engine
US5369989A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Jul 7, 1993 |
| Grant date | Dec 6, 1994 |
| Priority date | — |
| Expiry date | Jul 7, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01M15/09
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A simple, reliable, compact and inexpensive automobile engine misfiring detection system includes a basic capacitive pressure transducer, attached to a bleeder pipeline equidistantly from each point where the exhaust manifold is attached to the engine, and made of two closely spaced insulating plates whose opposed faces contain conductive layers, and one of which plates is a flexible diaphragm of low mechanical hysteresis. The transducer is thus coupled to a variable exhaust gas pressure source which under normal operating conditions remains at a substantially constant pressure level. The output signal from the transducer has its high-frequency AC component attenuated by a low-pass filter, whose output in turn has its DC component substantially removed by capacitive blocking, after which the remaining AC output is then amplified by a circuit including an operational amplifier. This AC-amplified signal is then compared with a "reduced-magnitude average" reference signal (produced by an AC-to-DC conversion side-circuit followed by magnitude-level adjustment). The comparator output triggers a one-shot monostable multivibrator used to produce an on-off switching signal which operates a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.