Vacuum actuated automatic temperature control system with actuator pressure signal feedback
US4147205A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 12, 1977 |
| Grant date | Apr 3, 1979 |
| Priority date | — |
| Expiry date | Sep 12, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05D23/20
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An automatic control system for regulating the temperature of the passenger compartment in automotive vehicles is disclosed of the type in which a vacuum operated actuator is utilized to control the position of a blend air door, the position of the blend air door in turn controlling the temperature of the air circulated into the passenger compartment by proportioning the flow of cooled air circulated through a heater prior to entering the passenger compartment. This air flow is utilized to correct the temperature level in the passenger compartment. The disclosed control system features a nulling pressure signal feedback loop in which the error signal developed by the difference in the temperature selector and sensor signals acts on a vacuum modulator to generate an actuator pressure level which is sensed and a corresponding electrical signal used to null the temperature error signal, to provide a stabilizing feedback loop in the control system. A particular vacuum modulator structure is also disclosed in which a pair of heated bimetal actuator devices are utilized to control communication of a vent port and a source of vacuum pressure with an interior chamber, the resulting pressur…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.