Fluid handling – Processes
Patent
1998-10-26
2000-02-01
Ferensic, Denise L.
Fluid handling
Processes
251 11, 25112901, 60527, F16K 3100, F16K 3102, E03B 100
Patent
active
060191139
ABSTRACT:
An improved method and apparatus for opening and closing a high performance shape memory alloy (SMA) fuel injector that minimizes performance variations due to changes in ambient temperature. When opening the injector to commence fuel injection, a relatively high voltage is applied to an SMA element of the injector to quickly heat the element to its high temperature state, quickly opening the valve. The current level is monitored as a measure of the element resistivity, and when the determined resistivity indicates that the high temperature state transition is complete, the voltage is reduced to a hold value, sufficient to continue resistivity measurement. When the determined resistivity indicates that the element is beginning to transition back to the ambient temperature state, the high voltage is re-applied to begin a new control cycle. To close the injector, the electric heating is discontinued, and fuel circulating through the injector cools the element to its ambient temperature state. The variability in opening response is reduced because the high voltage is significantly higher than a voltage that would thermally damage the SMA element if sustained, and the resistivity feedback during application of the high voltage is used to control the timing of the current reduction. The variability in closing response is reduced by the repeated switching between high and low voltage control, which controls the temperature of the element, and thereby maintains the element in a state of readiness to return to the ambient temperature state. Additionally, the repeated switching between high and low voltage control limits the peak temperature of the SMA element, and prevents damage to the element if the circulating fuel fails to adequately cool the element. Finally, the use of current measurement in the control circuit permits reliable determination of the resistivity of the SMA element without requiring external thermal sensors.
REFERENCES:
patent: 3229956 (1966-01-01), White
patent: 3400906 (1968-09-01), Stocklin
patent: 3613732 (1971-10-01), Willson et al.
patent: 3974844 (1976-08-01), Pimentel
patent: 4551974 (1985-11-01), Yaeger et al.
patent: 4736587 (1988-04-01), Suzuki
patent: 4747887 (1988-05-01), Honma
patent: 4973024 (1990-11-01), Homma
patent: 5211371 (1993-05-01), Coffee
patent: 5325880 (1994-07-01), Johnson et al.
patent: 5619177 (1997-04-01), Johnson et al.
Allston Brian Keith
Knebel Albert Martin
Salemi Michael Raymond
Cichosz Vincent A.
Ferensic Denise L.
General Motors Corporation
Kim Joanne Y.
LandOfFree
Method and apparatus for controlling a shape memory alloy fuel i does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for controlling a shape memory alloy fuel i, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for controlling a shape memory alloy fuel i will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-930464