Diagnostics for two-mode variable valve activation devices
US7761217B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 4, 2008 |
| Grant date | Jul 20, 2010 |
| Priority date | — |
| Expiry date | Jan 20, 2029 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A method for detecting a low-lift or zero-lift failure mode in a variable valve activation system of an internal combustion engine includes the steps of positioning a piezo-electric element that acts as a radio frequency transmitter relative to a lost motion spring of a two-mode variable valve activation lost motion device, subjecting the piezo-electric element to a compression load when a load from displacement of a lobe of a camshaft acts on the lost motion spring, broadcasting a radio frequency signal each time the piezo-electric element is subjected to the compression load, and evaluating the presence or absence of the broadcasted radio frequency signal in relation to an expected presence or absence of the radio frequency signal. The direct measurement of the mode of each two-mode device is both more reliable and more efficient in the use of engine controller resources compared to currently existing diagnostic methods.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.