Abstract: Electronic circuitry and control algorithms are described to automatically establish the output voltage of a linear exhaust gas oxygen sensor (e.g., a UEGO sensor) corresponding to an exhaust air-fuel ratio of stoichiometry. The apparatus and control logic herein described may be used to adaptively correct the setpoint of an air-fuel ratio control system in which a UEGO sensor is used in a feedback loop to adjust the fuel injection quantity of an internal combustion engine.

Abstract: Electronic circuitry and control algorithms are described to automatically establish the output voltage of a linear exhaust gas oxygen sensor (e.g., a UEGO sensor) corresponding to an exhaust air-fuel ratio of stoichiometry. The apparatus and control logic herein described may be used to adaptively correct the setpoint of an air-fuel ratio control system in which a UEGO sensor is used in a feedback loop to adjust the fuel injection quantity of an internal combustion engine.

Abstract: A method and system for determining steady state and real time engine oil consumption of an automotive engine which generates exhaust gases containing oil and fuel having a known sulphur content. The system includes an exhaust gas conditioner coupled to the exhaust manifold of the engine for extracting an exhaust gas sample and converting the exhaust sample into a combustion product. The system also includes a high temperature sampler for automatically regulating the amount of the combustion product independent of changes in back pressure of the engine. The system further includes a fluorescent detector for generating a sulphur dioxide content signal having a value corresponding to the sulphur dioxide contained in the regulated combustion product.

Abstract: Exhaust gas constituents of an exhaust gas stream are measured by drawing a proportional sample of exhaust gas through a capillary tube inserted into the exhaust gas stream. The capillary tube is controllably heated to avoid distortion of the reading due to condensation. The mass flowing in the capillary tube is determined by sensing the pressure drop across the length of the capillary tube.

Abstract: A method and associated apparatus for on-line gas analysis of a multicomponent gas emission flow, comprising: continuously withdrawing and regulating the pressure of a first sample flow from the emission flow, continuously withdrawing a second sample flow from the first sample flow, the second flow sample being diluted with mass controlled amounts of diluent (N.sub.

Abstract: A system for measuring an automotive engine exhaust constituent includes a meter for measuring the mass of air flowing through the engine and for generating a flow signal corresponding to the airflow, and a sample handling apparatus for separating a fraction of the exhaust flowing through the engine and for conducting the exhaust fraction to an analyzer. The system further includes diluent adding means for doping the extracted exhaust fraction with a diluent gas upstream of the analyzer and a processor for receiving the mass flow signal from the engine mass flow meter and for operating the diluent adding device in response to the flow signal. The processor operates the diluent valve such that the flow rate of exhaust gas into the analyzer remains a relatively constant fraction of the total exhaust flowing from the engine.

Abstract: Provided is a method and circuit for measuring on a real-time basis trace constituents in vehicle engine exhaust. The control circuit operates to maintain a small, constant concentration of a selected electrolyte constituent reactive with the exhaust constituent sought to be measured. The amount of current necessary to regenerate and maintain the concentration of the selected electrolyte constituent is continuously measured to generate a real-time electrical signal proportional to the mass flow of the exhaust constituent entering the electrochemical cell.

Abstract: A method and apparatus for linearly determining the air/fuel ratio of an internal combustion engine by measuring the oxygen concentration of the exhaust gases provides a linear air/fuel output signal from a single sensor. The sensor is time shared between a current driving or oxygen pumping mode in which a current is applied to the sensor to pump oxygen through the sensor toward one or the other surface, and a voltage sensing mode in which the voltage across the sensor is monitored. A time share circuit switches between the two modes of operation. During the current mode, the oxygen concentration is changed at the sensor surface by the passage of oxygen ion current through the sensor. During the voltage mode, the sensor voltage is measured. Feedback provides necessary current during the current mode to hold the bias voltage substantially constant. The resulting current is a linear measure of the air/fuel ratio of the internal combustion engine as engine operation departs from stoichiometry.

Abstract: A method and apparatus for measuring the electrical conductivity of a liquid comprises an electrically insulating housing through which the liquid flows, and four electrodes inserted into the path of the liquid flowing through the housing. The first and third electrodes are current electrodes and the second and fourth electrodes are voltage electrodes. An AC current is injected into the first current electrode and exits at the second current electrode, with the resulting AC voltage across the voltage electrodes being measured. The first current electrode is driven to maintain a constant value of AC voltage on the voltage electrodes while measuring the current flow in the second current electrode which is representative of the electrical conductivity of the liquid. A DC bias voltage source is provided and is coupled to each of the electrodes by a resistor and a capacitor to prevent coating or plating of the electrodes.

Abstract: A circuit and method for measuring the capacitance of a medium independent of the resistivity of the medium. A triangular voltage is applied to plates immersed in the medium to generate both a resistive current component in phase with the triangular voltage and a capacitive current component in phase with a differential of the triangular voltage. The resistive and capacitive current components are summed with a selectable current which is provided having a phase .pi. radians out of phase with the triangular voltage and having an amplitude related to a control signal. The summed current is sampled over a time period phase shifted from the capacitive current component and then integrated so that the capacitive current component integrates to zero and the integral of the resistive current component minus the selectable current provides the control signal. In response to the control signal, the selectable current is varied until the sum of the selectable current and resistive current component are nulled.

Abstract: A method is disclosed of making an on-line gas analysis of a multicomponent gas emission flow by (a) continuously sequestering a sample flow from the gas emission flow, which sample flow may be filtered to substantially eliminate solid or liquid particles, diluted to lower its dew point to below room temperature, and changed in either temperature and/or pressure to be substantially the same in temperature and pressure as that of gases used to create reference transmission frequency spectral data employed in step (d); (b) continuously irradiating the sample flow with an electromagnetic radiation beam while modulating the amplitude of infrared frequencies in the audio frequency range of the beam, either prior to or immediately subsequent to irradiation of the sample flow, to produce electromagnetic signals having discernible amplitude variations resulting from spectral interference patterns; (c) detecting and collecting the signals at a sufficiently high rate to substantially completely distinguish between adja

Abstract: A method is disclosed of making an on-line gas analysis of a multicomponent gas emission flow by (a) continuously sequestering a sample flow from the gas emission flow, which sample flow has been filtered to substantially eliminate solid or liquid particles, diluted to lower its dew point to below room temperature, and changed in either temperature and/or pressure to be substantially the same in temperature and pressure as that of gases used to create reference transmission frequency spectral data deployed in step (d); (b) continuously irradiating the sample flow with an electromagnetic radiation beam while modulating the amplitude of infrared frequencies in the audio frequency range of the beam, either prior to or immediately subsequent to irradiation of the sample flow, to produce electromagnetic signals having discernible amplitude variations resulting from spectral interference patterns; (c) detecting and collecting the signals at a sufficiently high rate to substantially completely distinguish between ad

Abstract: The invention is directed to an instrument for measuring the absolute electrical conductivity of liquids, which instrument may be employed on-line in a recirculating paint bath to measure the conductivity of the paint. The instrument comprises a four electrode probe and a meter which comprises a device for generating and controlling an AC current connected to the first electrode such that a constant AC voltage is maintained across the second and fourth electrodes and a device for measuring and detecting an AC current connected to the third electrode, wherein the fourth electrode is maintained at the same potential as a nearby ground.

Abstract: A method is disclosed for measuring the air to fuel ratio of an air/fuel mixture being supplied to a combustion process. This method has the following steps. An oxygen sensor station is established at which the sensor senses the difference in oxygen partial pressure from a first reference side thereof to a second oxygen measurement side thereof. The oxygen sensor is maintained at a predetermined temperature and at a pressure below atmospheric pressure. The oxygen sensor is calibrated so that the measurement thereby of an EMF between the first reference side thereof and the second oxygen measurement side thereof is indicative of the oxygen partial pressure in a gas stream passing by the oxygen measurement side thereof. A sample gas stream is drawn into the pressure across the second oxygen measurement side of the oxygen sensor. This pressure is one which allows samples to be drawn at a constant flow rate independent of that pressure. A fixed amount of oxygen is added to the sample gas stream.

Abstract: This specification teaches a basic method of obtaining on a continuous basis an instantaneous indication of the air to fuel ratio of an air/fuel mixture being fed to a combustion process. The process may take place in an internal combustion engine or, for example, in a power plant. Modifications of the method are taught to obtain such information as the hydrogen to carbon ratio of the fuel being burned in the combustion process, the oxygen equivalence of the air/fuel mixture being burned, the air mass flow through the combustion process, the fuel mass flow through the combustion process, instantaneous fuel economy of a vehicle in which a combustion process is being carried out to propel the vehicle, and the oxygen concentration in the exhaust gases from the combustion process.