Abstract: An on-road driving test system includes a determination condition storing unit, a vehicle speed storing unit, a predicted vehicle speed distribution calculating unit, and a determining unit. The determination condition storing unit stores a determination condition including at least a vehicle speed distribution condition for determining whether an on-road driving test is valid. The vehicle speed storing unit stores an actual measured vehicle speed actually measured at each geographical point by one or more vehicles. The predicted vehicle speed distribution calculating unit calculates a predicted vehicle speed distribution based on the actual measured vehicle speed, the predicted vehicle speed distribution being a vehicle speed distribution predicted to be obtained if a vehicle is driven on a set driving route. The determining unit determines whether the predicted vehicle speed distribution satisfies the vehicle speed distribution condition.

Abstract: The present invention provides a method for easily measuring nitrogen oxide concentration of an engine vehicle emission. The method can measure vehicle emission from an engine of a vehicle in travel with high precision even in regions other than the lean region, that is, regions from the stoichiometrical region to the rich region by using a NOx sensor exclusively used for the lean region. The present invention has an arrangement in which a NOx sensor that is exclusively used for the lean region is installed in an exhaust pipe 3 connected to the engine 2. Air (secondary air) A is introduced into the exhaust pipe 3 on the upstream side of the NOx sensor 6 so that the NOx sensor 6 is allowed to measure the concentration of NOx in the engine vehicle emission diluted by air A. Thus, the NOx concentration in the engine vehicle emission before dilution G is obtained by using the measured value of the NOx concentration after dilution and by using a dilution ratio.

Abstract: The present invention provides a method for easily measuring a brake mean effective pressure of a running vehicle. An air flow sensor, a ? sensor and a data collecting apparatus are mounted to the vehicle. A running speed and engine speed from the vehicle while actually running on a road surface, and output of the air flow sensor an the ? sensor are inputted to the data collecting apparatus. Specific fuel consumption is obtained from an intake air amount and ratio of excessive air in exhaust gas. Output of an engine is obtained from a relation between the specific fuel consumption and the engine speed.

Abstract: The present invention provides a simple method of measuring NOx in a running vehicle. While running on an actual road surface, the weight of NOx emitted from an engine of the running vehicle can be found more simply and accurately. The present invention comprises mounting a NOx analyzer, an air-fuel ratio sensor, and a data collection device on a vehicle, allowing the vehicle to run on the actual road surface, introducing the exhaust gas emitted while running on the actual road surface to a NOx analyzer to determine the concentration of NOx contained in the exhaust gas, determining a flow rate of the exhaust gas by using a fuel injection quantity based on a fuel injection pulse output from an electronic control unit mounted on the vehicle and an output from the air-fuel ratio sensor, and determining the weight of NOx emitted from the engine from the flow rate of the exhaust gas and the concentration of NOx.

Abstract: The present invention provides a method for easily measuring a brake mean effective pressure of a running vehicle. An air flow sensor, a &lgr; sensor and a data collecting apparatus are mounted to the vehicle. A running speed and engine speed from the vehicle while actually running on a road surface, and output of the air flow sensor an the &lgr; sensor are inputted to the data collecting apparatus. Specific fuel consumption is obtained from an intake air amount and ratio of excessive air in exhaust gas. Output of an engine is obtained from a relation between the specific fuel consumption and the engine speed.

Abstract: The present invention provides a method for easily measuring a brake mean effective pressure of a running vehicle. An air flow sensor, a &lgr; sensor and a data collecting apparatus are mounted to the vehicle. A running speed and engine speed from the vehicle while actually running on a road surface, and output of the air flow sensor an the &lgr; sensor are inputted to the data collecting apparatus. Specific fuel consumption is obtained from an intake air amount and ratio of excessive air in exhaust gas. Output of an engine is obtained from a relation between the specific fuel consumption and the engine speed.

Abstract: The present invention provides a method for easily measuring nitrogen oxide concentration of an engine vehicle emission. The method can measure vehicle emission from an engine of a vehicle in travel with high precision even in regions other than the lean region, that is, regions from the stoichiometrical region to the rich region by using a NOx sensor exclusively used for the lean region. The present invention has an arrangement in which a NOx sensor that is exclusively used for the lean region is installed in an exhaust pipe 3 connected to the engine 2. Air (secondary air) A is introduced into the exhaust pipe 3 on the upstream side of the NOx sensor 6 so that the NOx sensor 6 is allowed to measure the concentration of NOx in the engine vehicle emission diluted by air A. Thus, the NOx concentration in the engine vehicle emission before dilution G is obtained by using the measured value of the NOx concentration after dilution and by using a dilution ratio.

Abstract: A method and apparatus for analyzing fluid by a multi-fluid modulation mode is characterized by subjecting a plurality of sample fluids (which may be different or a single sample fluid divided into a plurality of systems) to a fluid modulation by reference fluids at various frequencies, respectively. An analytical portion provided with only one sensor is simultaneously and continuously supplied with the respective sample fluids. An output signal from the sensor in the analytical portion is divided into signal components of the respective modulation frequencies for the respective sample fluids to rectify and level, whereby obtaining analyzed values about the respective sample fluids is achieved.

Abstract: A method for analyzing fluid by a multi-fluid modulation mode is characterized by subjecting a plurality of sample fluids (which may be different or a single sample fluid divided into a plurality of systems) to a fluid modulation by reference fluids at various frequencies, respectively. An analytical portion provided with only one sensor is simultaneously and continuously supplied with the respective sample fluids. An output signal from the sensor in the analytical portion is divided into signal components of the respective modulation frequencies for the respective sample fluids to rectify and level, whereby obtaining analyzed values about the respective sample fluids is achieved.

Abstract: A temperature compensating circuit designed in two parts, a temperature-pulse width conversion circuit (X) and a temperature compensating circuit (Y.sub.N) permit the sharing of the temperature-pulse width conversion circuit by a plurality of temperature compensating circuits. Each temperature conversion circuit is relatively uncomplicated in construction, utilizing only resistors and a switch means. The temperature-pulse width conversion circuit utilizes a temperature sensitive element, like a thermistor, in a circuit with an operational amplifier. The output of the operational amplifier is supplied to a pulse width converter for generating the pulse width signal that carries the temperature compensation factor to be used in temperatures compensating the signal received by the temperature compensating circuit.

Abstract: A sensitivity calibration circuit for use in an absorption analyzer provided with a check-signal generator for easily checking the sensitivity, includes a temperature compensating circuit for use in an optical system for compensating for a temperature draft due to said optical system and a temperature compensation circuit for use in a sample system for compensating for a temperature draft due to the sample system.

Abstract: A sensitivity-calibration circuit for an HC analyzer includes a scale factor adjuster for setting a scale factor in the analyzer for determining an n-hexane reduced gas concentration value of propane gas used during sensitivity-calibration of the analyzer and a sensitivity adjuster for adjusting the sensitivity of the analyzer and a switching means for switching the circuit between a first calibration state and a second measurement state.