Abstract: An apparatus for detecting a combustion condition, such as knock or misfire, includes an incremental integrator in proximity with an ignition coil and provides a stream of digital pulses to a remote control unit, such as an engine control unit. The incremental integrator includes an integration device, such as a capacitor, a threshold comparator, and a pulse generator. A charging current proportional to an ion current charges the capacitor to a preset level wherein the threshold comparator changes state, causing the pulse generator to generate a pulse. The pulse is provided to the control unit, which may include a counter for counting the stream of pulses. The generated pulse also is fed back to reset the integration device, for example discharge of the capacitor. The process is repeated during a condition window, such as a knock window or a combustion window. The count held in the counter of the control unit is indicative of the level of combustion or knock, as applicable.

Abstract: An impulse noise suppression circuit for an integrator-based ion current signal processing system includes a one-shot circuit activated by a trigger signal that is produced when a noise transient in a bandpass filtered ion current signal exceeds a predetermined threshold. The output pulse of the one-shot circuit is selected to have a pulse width configured to mask a substantial portion of the noise transient without masking the remaining filtered ion current signal during the remainder of a knock window in which knock is detected.

Abstract: An imaging system for producing a panoramic radiograph of a patient's jaw for dental analysis includes an X-ray source (2) carried at one end of an arm (1) and detector means (7) at the other end. The front surface of the detector means (7) carries scintillator material (8) which substantially solely defines the area of the detector means at which the image information is captured. The secondary diaphragm or slot used in conventional panoramic X-ray imaging systems can thus be omitted, giving a less complicated system.

Abstract: An improved method of identifying the cylinder combustion sequence of a four-stroke internal combustion engine accepts of rejects an assumed combustion sequence based on measured ion current combustion quality (CQ) indications. Individual CQ indications for the various engine cylinders are algebraically combined as a function of the assumed combustion sequence so that the combined CQ indication increases in a first polarity if the assumed combustion sequence is correct, and in a second polarity if the assumed combustion sequence is incorrect. When the absolute value of the combined CQ indication exceeds a threshold, the polarity of the combined CQ indication is used to either accept or reject the assumed combustion sequence.

Abstract: In an ignition coil assembly of an ion sensing ignition system having an ignition coil output, a buffered ion-sense current source circuit is provided and includes a current sensing circuit, the current sensing circuit being disposed so as to be communicated with the ignition coil output and an active current source circuit, the active current source circuit being disposed so as to be communicated with the current sensing circuit and a current measuring device.

Abstract: Disclosed is a bias and measuring circuit that improves the ion sense measurement and ignition performance of an Ion Sense Ignition system where the ion current signal processing is implemented remote from the ignition coil. Specifically, the bias and measuring circuit of the invention reduces the effects of secondary harness capacitance on the ion current signal, minimizes the effects of harness electrical leakage and reduces the chances for “spark-on-make” (an ignition firing when the ignition coil primary is initially energized).

Abstract: A device for rejecting noise in an ion-sense ignition knock signal compares an integrated knock signal to a peak knock signal multiplied by a time factor to determine the presence of noise. A bandpass filter coupled to an engine's spark plug through ion-sensing circuitry generates a filtered knock signal. The filtered knock signal is passed through a rectifier to produce a rectified knock signal. The rectified knock signal is then passed through an integrator and a peak detector to produce an integrated knock signal and a peak knock signal, respectively. The peak knock signal is multiplied by a predetermined time factor and the result is compared to the integrated knock signal. If the result is less than the integrated knock signal, then no noise disturbance occurred and the integrated knock signal is passed on to a knock detector.

Abstract: Disclosed is a bias and measuring circuit that improves the ion sense measurement and ignition performance of an Ion Sense Ignition system where the ion current signal processing is implemented remote from the ignition coil. Specifically, the bias and measuring circuit of the invention reduces the effects of secondary harness capacitance on the ion current signal, minimizes the effects of harness electrical leakage and reduces the chances for “spark-on-make” (an ignition firing when the ignition coil primary is initially energized).

Abstract: A plasma processing device is described which is modular and can be scaled up by assembly together with similar devices to provide a capability for large area processing. The device includes a housing which contains an array of RF coils and into which a process gas is fed. The article to be processed is disposed close to the housing and egress of the process gas from the housing to the process region is resisted so as to maintain a positive pressure differential between the housing and the process region.