Abstract: A compact and high-accuracy angular position measuring device is provided which has magnets installed in a rotor core and a magnetic sensor installed in a stator core. The magnetic sensor produces an output indicative of an angular position of the rotor core as a function of a change in density of magnetic flux produced by the magnets. The magnets are so arranged in the rotor core that the same poles are opposed magnetically to produce a repellent force in magnetic fields of the magnets, thereby causing the magnetic flux to go to the magnetic sensor through the rotor core. This eliminates the need for an air gap between the stator core and the poles of the magnets which is formed in a conventional device, thus allowing the device to be reduced in size and an error in output of the device to be decreased.

Abstract: Hall ICs constituting a redundant throttle valve position sensor are used to measure a rotational angle value indicative of a position of a throttle valve and a temperature value indicative of an ambient temperature change, which is continuously monitored, around the Hall ICs. The rotational angle value measured by the Hall ICs is appropriately adjusted based on the measure temperature value of its own, and a throttle valve position is determined in an externally connected ECU based on the adjusted angle value. In addition, the temperature value measured by one Hall IC is inputted to the ECU. In the ECU, various control values, such as a resistance value of an electric motor, can be appropriately adjusted based on the measured temperature value.

Abstract: If outputs of a couple of Hall ICs constituting a throttle valve position sensor are within an operating range of throttle valve position, and if a relationship between the outputs are within a predetermined error range, both the Hall ICs are determined to be normal. In contrast, if the outputs are equal to an upper clamp voltage or a lower clamp voltage, and if a relationship between the outputs is out of the predetermined error range, at least one of the Hall ICs is determined to be abnormal. Furthermore, if the outputs are within a failure reference voltage range, it is determined that there is an abnormality between the throttle valve position sensor and an ECU. In this way, abnormalities in the sensor and abnormalities between the sensor and the ECU can also be detected.

Abstract: In the present invention, Hall ICs are mounted opposite to a permanent magnet fixed onto a rotary shaft of a throttle valve. The rotary shaft is rotated to adjust the throttle valve to a predetermined degree of opening and is fixed temporarily to that throttle opening. An output value corresponding to that throttle opening is written into the Hall ICs from the exterior. That is, writing of the throttle opening output value is done in only the final stage after completion of the mounting of the Hall ICs.