Abstract: A vehicle exhaust gas collection probe assembly for the collection of two independent exhaust gas samples from a tailpipe system of a vehicle exhaust system comprises a first collector for collecting an undiluted exhaust gas sample from within the exhaust system and second collection means for collecting the entirety of exhaust gas exiting from an end of the tailpipe system. The second collection means comprises a conical collector having a first open end of a diameter greater than that of the tailpipe system positioned adjacent the end of the tailpipe system and a second end of small diameter coupled to a collection conduit. The first collector comprises a hollow probe having a flexible portion for insertion into the tailpipe system coupled to a conduit positioned along a main longitudinal axis of the conical collector, extending into the conical collector, and being supported by the conical collector.

Abstract: A method and apparatus for improving the integrity of a vehicle test procedure insures that the vehicle to which a varying test parameter is applied is the same as the vehicle whose response is required. A random variation to the test parameter is introduced, and the response of a chosen vehicle characteristic to the variation is monitored and correlated with the variations. A high correlation confirms that the vehicle whose response is being monitored is in fact the vehicle to which the parameter is applied. The method may advantageously be used in connection with EPA-sanctioned exhaust emission test protocols.

Abstract: A universal sensor includes a dielectric substrate, a curved surface capacitive plate mounted to the substrate and responsive to the electromagnetic field (EMF) of an integral coil ignition system, and a rotatable lever arm mounted to the substrate and having wire holders for receiving the EMF of spark plug wires of a distributorless ignition system (DIS)ignition, the arm operable in a closed position to conduct the DIS EMF to the plate, and operable in an open position for securing a standard ignition coil secondary wire between the arm and the plate allowing the standard wire EMF to be coupled to the capacitive plate.

Abstract: Engine timing measurement apparatus receives the engine gear tooth signal, sensed combustion, and a crankshaft index (CI) of top dead center (TDC). The apparatus includes a whole tooth interval counter for providing a whole number count of each complete tooth interval, and partial tooth counters for counting incomplete tooth intervals as the ratio of clock pulses counted in a present incomplete tooth interval divided by clock pulses counted in a preceding complete tooth interval, the partial count added to the whole count to provide a decimal value indicative of engine timing.

Abstract: Compression is measured in an internal combustion engine by sensing the deceleration in sub-cyclic engine speed resulting from each cylinder's compression stroke while the engine is decelerating without fuel to the cylinders and without engine load.

Abstract: A solid state power switch includes a gated switch for connecting electrical power to a load whenever the actual load current is less than selected current reference values.

Abstract: Relative compression in an asymmetric internal combustion (IC) engine is determined by measuring the change in speed of the engine crankshaft while the engine is cranked without ignition during each cylinder sub-cycle; the actual change in speed from a maximum to a minimum is measured during the compression stroke of each cylinder of the cylinder bank which is first to fire in the alternating left bank/right bank firing order of the engine, and the change in speed from a minimum to a maximum is measured during the expansion stroke of each cylinder of the second bank, such that the changes in engine speed over one engine cycle is provided as a sequence of delta speed signals associated alternately with a compression stroke and next with an expansion stroke for succeeding left bank and right bank cylinder displacements in accordance with the firing order; the delta speed signal magnitude associated with each cylinder, i.e.

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 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 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.

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: Indications of speed of an internal combustion engine are derived from an engine member rotating directly with the crankshaft, such as the teeth on the flywheel, so as to provide indications for speed measurements on a sub-cycle basis (that is, many times during each revolution), a timer is started after a threshold speed is reached as determined by comparison with the sub-cyclic speed indications, and a measurement of speed is made contemporaneously with starting the counter; after an elapsed time interval which may be on the order of several cycles, which is determined by the acceleration of the engine, the timer is stopped and the speed is once again measured. In one embodiment, the timer is allowed to run through a known large angle of revolution of the engine, such as several cycles, as is determined by counting successive signals indicating a particular cyclic angular position of the engine, after which the timer is stopped and the speed is measured contemporaneously therewith.