| 摘要 |
<p>A shape memory alloy actuator assembly for a fuel injector, having a small package integral design, wherein the response times of the shape memory alloy element is decreased to less than about 1 millisecond by forced, convective heat transfer from the SMA element or elements. The forced, convective heat transfer is provided by the circulation of fluid across the SMA element by a metering orifice plate, which directs a fluid flow across the SMA element so as to maximize the area of contact between the fuel and the SMA element, regardless of whether the fuel injection valve is opened or closed. Use of forced convective heat transfer in accordance with the present invention allows greater power input levels than previously possible without resulting in an over-temperature condition of the SMA alloy, as well as constant response times. Actuator production costs are reduced by 40%, whereby side fame rails of the actuator are eliminated, and the spacer and the orifice plate are incorporated into a second wafer, which is bonded to the first wafer, which includes SMA material and a valve seal island.</p> |
