Abstract: A circuit configuration wherein a plurality of solenoid driver circuits are all coupled together such that the high voltage supply associated with one driver circuit is connected in parallel with the high voltage supply of another driver circuit. Each driver circuit includes a high voltage select switch, a select switch, and a modulation switch, all of which switches are coupled to and controlled by an electronic controller such that back EMF created by the solenoid coil in each respective driver circuit can be recaptured by charging the high voltage supply associated with that driver circuit. This recaptured energy can then be utilized to not only provide current flow to the solenoid coil associated with that particular driver circuit, but such energy can likewise be utilized to recharge any plurality of the other high voltage supplies associated with the other driver circuits, even while the solenoid coils of such driver circuits are being powered by their respective high voltage supply.

Abstract: An engine controller including programmable interrupt means connected with an engine speed sensor permits the controller to have configurable speed timing interrupts.

Abstract: An apparatus and method for varying the current levels of a fuel injection signal used in connection with an electronically controlled hydraulic actuator unit injector fuel system is disclosed. The apparatus and method varies the current level of the fuel injection signal delivered to the unit injector based on sensed engine parameters, which preferably include a sensed pressure of hydraulic actuating fluid and a sensed temperature of the engine.

Abstract: A solenoid driver circuit is controlled by an electronic control module ("ECM") and eliminates many components required for a high voltage power supply required by the prior art. The solenoid driver circuit includes a high voltage select switch, a select switch and a modulation switch that are controlled by the ECM. The ECM causes the switches to be opened and closed so that the back EMF created by the solenoid coil when the modulation switch is opened can be recaptured by charging a capacitor. That energy can then be used to energize the solenoid coil.

Abstract: A control system for an internal combustion engine having a plurality of cylinders and a rotatable crankshaft. Each cylinder has an electronically actuatable intake valve, exhaust valve and fuel injector. The control system includes a sensor which monitors the rotation of the crankshaft and responsively produces a crankshaft pulsetrain. A computer produces operator parameter signals. The operator parameter signals including one of a plurality of operating modes of the engine. A first microprocessor receives the crankshaft pulsetrain, responsively determines the speed of the engine and produces a signal representative of the determined engine speed. A second microprocessor receives the operator parameter signals and the engine speed signal, responsively determines valve and injection events for each cylinder to responsively achieve the one engine operating mode. The second microprocessor produces signals representative of the determined valve and injection events.