Abstract: A drive circuit is provided in a full H-bridge and half H-bridge configuration for controlling one or more piezoelectric fuel injectors. The drive circuit includes a voltage input for receiving a voltage signal, an energy storage device coupled to the voltage input for storing an electrical charge, a bidirectional current path coupled to one or more piezoelectric injectors, an inductor coupled in series with the piezoelectric injector(s) in the bidirectional current path, and switching circuitry for controlling current flow through the piezoelectric injector(s) and the inductor to open and close the piezoelectric injector(s). The switching circuitry is controlled to provide a recirculation current to recover energy stored in the piezoelectric injector(s) for storage in the energy storage device.

Abstract: A control system for an electric heater, e.g., an electric catalyst heater (ECH), includes a current sensor, a voltage sensor, a switching element, and a control circuit. The control circuit is coupled to the current sensor, the voltage sensor and a control terminal of the switching element and varies a control signal on the control terminal to maintain the temperature of the heating element within a predetermined temperature range.

Abstract: Certain glycerides are effective flow-promoting agents in powdered acrylic coating formulations. As a powdered acrylic resin coating material is applied by electrostatic sprayer means to a substrate, a rough layer of discrete particles is formed. To produce a commercially acceptable coating, this layer must be fused into a continuous film and induced to flow into a smooth, glossy finish. The subject glycerides, which may be acetylated, promote such flow and produce a surface finish equivalent to that of the conventional acrylic paints which employ an organic solvent vehicle.