Idle air control system diagnostic
US5408871A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 27, 1994 |
| Grant date | Apr 25, 1995 |
| Priority date | — |
| Expiry date | Jan 27, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/40
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An idle air control system diagnostic for an internal combustion engine which utilizes RPM, engine timing and intake airflow measurements to detect the presence of idle RPM faults and eliminate or verify the idle air control system as the fault source. Engine idle RPM is measured and compared with a commanded idle RPM, and if within a predetermined range, an idle RPM fault exists and one of two additional tests (non-intrusive and intrusive) is conducted to determine whether the idle air control system is the source of the fault. In the non-intrusive test, intake airflow is measured and compared to a predetermined intake airflow value, and if not within a predetermined range, the idle air control system is determined to be the fault source. In the intrusive test, variations in intake airflow (or intake manifold pressure) are measured in response to variations in the movement of the engine throttle-bypass airway pintle. If no intake airflow variations are detected, the idle air control system is determined to be the fault source.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.