Hydraulic fluid change indicating device for automatic transmission
US7433770B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 3, 2004 |
| Grant date | Oct 7, 2008 |
| Priority date | — |
| Expiry date | Nov 22, 2026 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16H57/0405
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A hydraulic fluid change indicating device for an automatic transmission includes a first deterioration rate calculating unit; a deterioration acceleration coefficient calculating unit; and a thermal hydraulic fluid deterioration calculating unit for calculating a thermal hydraulic fluid deterioration according to the first deterioration rate and the deterioration acceleration coefficient. The device further includes a second deterioration rate calculating unit according to an engine speed, input shaft speed, and output shaft speed; a mechanical hydraulic fluid deterioration calculating unit for calculating a mechanical fluid deterioration according to the second deterioration rate; and a determining unit for determining whether or not the thermal hydraulic fluid deterioration or the mechanical hydraulic fluid deterioration is greater than a predetermined hydraulic fluid change threshold.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.