Variable camshaft timing for internal combustion engine
US5107804A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 11, 1991 |
| Grant date | Apr 28, 1992 |
| Priority date | — |
| Expiry date | Jun 11, 2011 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02B2075/027
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A camshaft (426) has a vane (460) secured to an end thereof for non-osciling rotation therewith. The camshaft also carries a sprocket (432) which can rotate with the camshaft but which is oscillatable with respect to the camshaft. The vane has opposed lobes (460a, 460b) which are received in opposed recesses (432a, 432b), respectively, of the sprocket. The recesses have greater circumferential extent than the lobes to permit the vane and sprocket to oscillate with respect to one another, and thereby permit the camshaft to change in phase relative to a crankshaft whose phase relative to the sprocket is fixed by virtue of a chain drive extending therebetween. The camshaft tends to change in reaction to pulses which it experiences during its normal operation, and it is permitted to change only in a given direction, either to advance or retard, by selectively blocking or permitting the flow of hydraulic fluid, preferably engine oil, through the return lines (494, 496) from the recesses by controlling the position of a spool (500) within a valve body (498) of a control valve in response to a signal indicative of an engine operating condition from an engine control unit (508).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.