Circuit for measuring ionization current in a combustion chamber of an internal combustion engine
US6954074B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 11, 2003 |
| Grant date | Oct 11, 2005 |
| Priority date | — |
| Expiry date | Aug 11, 2023 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02P2017/125
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A circuit for measuring ionization current in a combustion chamber of an internal combustion engine including an ignition coil, having a primary winding and a secondary winding, and an ignition plug. The ignition plug ignites an air/fuel mixture in the combustion chamber and produces an ignition current in response to ignition voltage from the ignition coil. A capacitor, charged by the ignition coil, provides a bias voltage producing an ionization current after ignition of the air/fuel mixture in the combustion chamber. A current mirror circuit produces an isolated current signal proportional to the ionization current. In the present invention, the ignition current and the ionization current flow in the same direction through the secondary winding of the ignition coil. The charged capacitor operates as a power source and, thus, the ignition current flows from the charged capacitor through the current mirror circuit and the ignition coil to the ignition plug.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.