Cylinder pressure based air-fuel ratio and engine control
US5878717A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 20, 1998 |
| Grant date | Mar 9, 1999 |
| Priority date | — |
| Expiry date | Mar 20, 2018 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D41/1475
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A system and method for controlling an air-fuel ratio of an internal combustion engine using a ratio of cylinder pressures measured within at least one cylinder. The air-fuel ratio control system includes an electronic control module (ECM) which computes a measured cylinder pressure ratio of the cylinder pressure measured at a predetermined crank angle before top dead center and the cylinder pressure measured at a predetermined crank angle after top dead center. The measured cylinder pressure ratio is compared with an optimal cylinder pressure ratio. Based upon the results of this comparison, the ECM then determines an adjusted air-fuel ratio which would modify the measured pressure ratio to equal the optimal pressure ratio. This system controls the air-fuel ratio by measuring the quality of combustion without the need to measure the amount of air or fuel actually delivered to the engine. The measured pressure ratio corresponds to an excess air ratio of the internal combustion engine at those operating conditions, wherein a measured excess air ratio of the engine may be obtained from the computed pressure ratio. The measured excess air ratio may be compared with an optimal excess a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.