Glow plug duty cycle modulating apparatus
US4312307A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 4, 1980 |
| Grant date | Jan 26, 1982 |
| Priority date | — |
| Expiry date | Feb 4, 2000 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02B3/06
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A control for modulating the duty cycle of diesel engine glow plugs has two heat sensitive, normally closed switches each thermally coupled to a respective positive temperature coefficient (PTC) of resistivity heater in turn thermally coupled to a common heat sink. The heat sensitive switches are serially connected to each other, to an ignition switch and to a glow plug relay. The PTC heaters are connected to a point between the heat sensitive switches and the relay and to ground. A third PTC heater is disposed on the heat sink intermediate the first and second heaters and thermally coupled to the heat sink. The third heater is connected to an alternator and serves to cut off power to the glow plugs after a selected after glow stage. The two heat sensitive switches can be selected to open at approximately the same temperature for a random operating mode or at slightly different temperatures for a sequential operating mode. The common operating mode is a redundant high reliability operating mode whereas the sequential operating mode, using slightly different temperatures allows one switch to control the cycling and the second to be a back up safety control. In one preferred embodime…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.