Thermostat setting diagnostics for internal combustion engine
US4069712A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 25, 1977 |
| Grant date | Jan 24, 1978 |
| Priority date | — |
| Expiry date | Mar 25, 1997 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF01P2025/08
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Electronic processing means are utilized in a composite measurement of performance of an engine cooling system thermostat, with diagnostic procedures to ensure viable measurement. The speed of the engine is initially tested to ensure the engine is at high idle speed, so that temperature in the cooling system will increase to that at which the thermostat will normally operate; and during the testing, the speed is continuously monitored to be sure it remains close to the initial test speed (near high idle) to minimize coolant pump pressure variations due to engine speed. Three temperature diagnostics are performed to ensure a viable test: first, if the temperature ever exceeds 15.degree. over the rated thermostat temperature, the test is terminated in a fault since the thermostat is presumed to be stuck in the closed position; second, if the temperature fails to increase by at least 2.degree. for each 2 minutes of operation above rated speed, the test is terminated in a fault since it is assumed that the thermostat is stuck in the open position; third, if the test is not completed within 5 minutes after the temperature reaching 5.degree. less than the rated thermostat temperature, th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.