Method and arrangement for checking the operability of an electric heater in a motor vehicle
US5218946A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 28, 1992 |
| Grant date | Jun 15, 1993 |
| Priority date | — |
| Expiry date | Sep 28, 2012 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D41/1494
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
The invention relates to a method and an arrangement for checking the operability of an electric heater in motor vehicles and especially the heater of an oxygen probe which is mounted in the exhaust gas channel of an internal combustion engine. It is necessary to determine the temperature-dependent electrical resistance and the temperature of the oxygen probe heater for a precise evaluation of the operational state of the oxygen probe heater. The basic principle of the invention is based upon the consideration that the measurement of the electrical resistance of the oxygen probe heater is then carried out when the oxygen probe heater has cooled down to the ambient temperature. Whether this cool down has taken place can be determined in various ways in accordance with the invention, for example, from the cool down of the engine block or by a comparison of the engine block temperature to the intake-air temperature. The operating state of the oxygen probe heater so determined is displayed to the driver by the activation of a corresponding control device and/or, if required, read into a fault memory.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.