Abstract: 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.

Abstract: A desmodromic cam driven variable valve timing (VVT) mechanism includes dual rotary opening and closing cams for actuating a rocker mechanism that drives valve actuating oscillating cams. The dual rotary cam drive positively actuates the rocker mechanism in both valve opening and valve closing directions and thus avoids the need to provide return springs as required in prior cam driven mechanisms to bias the mechanisms toward a valve closed position. A variable ratio slide and slot control lever drive as well as a back force limiting worm drive for the control shaft are combined with the desmodromic cam mechanism to provide additional system advantages.

Abstract: A linkless variable valve mechanism includes a rocker arm having a first end and a second end. A rocker roller is carried by the first end of the rocker arm, and engages an input cam lobe disposed upon an input shaft. A frame member having a first end and a second end is pivotally mounted upon the input shaft. The first end of the frame member is pivotally coupled to a control shaft, and the second end is pivotally coupled to the second end of the rocker arm. An output cam is pivotally mounted upon the input shaft. An output cam follower is attached to the output cam, and includes an inside surface. A sliding block is pivotally coupled to the second end of the rocker arm and engages the inside surface of the cam follower.

Abstract: A drive circuit for controlling at least one device having first and second electromagnetically operable actuators, the drive circuit having first and second terminals for connection to a voltage supply and comprising a first controllable switch in connection with one side of the actuators and the first terminal. Each actuator has an associated second controllable switch in connection with the other side of the respective actuator, whereby opening and closing of the first and second switches serves to control selection and actuation of the actuators. The circuit further comprises a sensor arrangement for providing independent sensing of the current flowing through each of the actuators, each actuator having an associated diode in connection with the respective second controllable switch to ensure current flows through the sensor arrangement when the first controllable switch is opened and the second controllable switch is closed.