Hydraulic control apparatus and hydraulic control method of vehicular automatic transmission
US7481734B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 18, 2006 |
| Grant date | Jan 27, 2009 |
| Priority date | — |
| Expiry date | Jul 25, 2027 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16H2061/1276
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A hydraulic control apparatus of a vehicular automatic transmission has a plurality of hydraulic friction engagement devices that are selectively engaged and released to establish a plurality of forward speed change stages of different speed change ratios. The forward speed change stages are achieved through engagement of predetermined friction engagement devices, of the plurality of friction engagement devices. If it is determined that a predetermined speed change stage corresponding to a predetermined shift output is not established, the hydraulic control apparatus identifies a hydraulic friction engagement device having a bad engagement that is a cause of the non-establishment of the predetermined speed change stage, on the basis of the state of engagement oil pressure of the predetermined friction engagement device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.