Abstract: A safety system for detecting an obstruction approaching closing doors includes a transmitter stack and a detector stack. Each transmitter stack includes a plurality of transmitter three-dimensional lenses. Each detector stack includes a plurality of detector three-dimensional lenses. The three-dimensional lenses are offset from the corresponding optical devices to angle an outgoing or incoming signal. The present invention results in more compact packaging for the safety system and in reduced cost of the assembly therefor.

Abstract: A safety system for detecting small objects that approach closing doors comprising a transmitter stack, a detector stack, and a controller including instructions to detect small objects as the doors are closing. A transmitter or a group of transmitters from the transmitter stack are powered sequentially resulting in an output from the detector stack. The controller compares each output from the detector stack with an average of all the outputs plus a threshold value. The outputs that exceed the average plus threshold value trigger the safety system to reverse closing operation of the doors.

Abstract: A safety system for detecting objects or persons that approach closing doors includes a plurality of detectors on one door and a plurality of transmitters on an opposite door. The plurality of transmitters emit a signal at an angle into a hallway. The intensity of the signal emitted from the transmitters is progressively reduced as the distance between the closing doors is decreasing. The reduction in intensity of the transmitted signal allows discrimination between actual targets and false targets.

Abstract: A serial signal communications system includes a central station unit connected through a balanced impedance signal communication bus to one or more remote station units.

Abstract: The exhaust back-pressure of an internal combustion (IC) engine is used to provide an indication of the relative combustion efficiency of the engine's cylinders. The instantaneous values of back-pressure are sensed at selected, sub-cyclic crankshaft angular intervals, within a full engine cycle, each angle interval being substantially less than that associated with a cylinder sub-cycle, each sensed value of back-pressure being identified by the sensed angle position to provide an indication of the sub-cyclic fluctuation in back-pressure as they occur at known cylinder exhaust stroke cycles within the engine cycle, thereby providing identification of each sub-cyclic back-pressure pulse as being associated with a particular engine cylinder, the relative magnitudes of the back-pressure pulses being compared with each other to provide indices of the relative combustion efficiency of each cylinder.

Abstract: Measurement of the operation of the accelerator pump of an internal combustion (IC) engine is provided while the engine is running under load by snapping the engine throttle from a steady state throttle position to a full throttle position and back within a time interval less than the response time of the engine power valve (enrichment valve), and comparing the relative magnitudes of the carbon monoxide (CO) and hydrocarbon (HC) constituents of the engine exhaust gas measured before and after the snap acceleration to provide an indication of the performance of the accelerator pump.

Abstract: The relative power contribution of each cylinder in an internal combustion (IC) engine which is connected through a common drive shaft to an engine load and which is running at a selected speed, is provided as the relative magnitudes of each cylinder's contribution to the fluctuations in a sub-cyclic net torque signal provided as the difference torque value between an instantaneous sub-cyclic engine torque signal and an instantaneous sub-cyclic load torque signal.

Abstract: The instantaneous values of intake manifold vacuum in an internal combustion (IC) engine running under load are measured to provide an indication of the relative performance and relative suction ability of each cylinder in the engine. The instantaneous values of manifold vacuum are sensed at selected, sub-cyclic crankshaft angle intervals within a full engine cycle, each angle interval being substantial less than that associated with a cylinder sub-cycle, each sensed value of manifold vacuum being identified by the sensed angle position to provide an indication of the sub-cyclic fluctuations in manifold vacuum as they occur at known cylinder intake strokes within the engine cycle, thereby providing identification of each sub-cyclic fluctuation in manifold vacuum as being associated with a particular cylinder, the relative magnitudes of the manifold vacuum fluctuations providing a relative indication of each cylinder's performance and suction ability within a common engine cycle.

Abstract: The spark voltage waveform at the secondary of the ignition coil of an internal combustion (IC) engine is sensed over a plurality of successive engine cycles. The instantaneous sub-cyclic position of the engine crankshaft is measured at successive crankshaft angle increments within each engine cycle and each sensed spark voltage signal is identified by the instantaneous value of crankshaft position at which it appears, thereby providing identification of each spark voltage signal with an associated cylinder of the engine. The number of samples for each cylinder together with the peak KV voltage magnitude and time duration of each are measured and the maximum, minimum and mean values of peak KV and spark duration for the spark signals associated with each cylinder together with the number of samples obtained are compared with the values obtained for each other cylinder to provide an indication of the relative sub-cyclic ignition efficiency of the ignition secondary circuit and the individual cylinders.