The present invention relates to a method of taking-in input data for controlling a motorcar and particularly to a method of taking-in input data in which a plurality of input data for a plurality of controls are taken in by commonly using an analog-to-digital (A/D) converter.
Recently, a microcomputer has been used in order to improve various kinds of control functions in a motorcar or automobile (hereinafter simply referred to as "car"). In a system using a microcomputer, however, it has been required to provide numbers of input devices corresponding to the various kinds of control functions in accordance with the various kinds and various uses of the cars.
As known well, the car control is attained by taking-in various measurement values from sensors mounted at various portions in the car. As such sensors, there are provided, for example, a water temperature sensor (TW), an atmosphere temperature sensor (TA1), a car room temperature sensor (TA2), a humidity sensor (VW), a suction amount sensor (QA), an exhaust gas sensor (V.lambda.), a throttle angle sensor (VT), a battery voltage sensor (VB), an AC generator output voltage sensor (VG), etc. The parenthesized letters represent the respective output values of the sensors. The measurement result of each of these sensors is produced with an analog value. Further to these sensors, there may be provided adjusting voltage terminals (V.sub.1, V.sub.2), checking points (V.sub.3, V.sub.4), etc. which are supplied with analog values, while they are not analog sensors. Further, there are provided an engine speed sensor (RPM), a wheel speed sensor (WS), a vehicle speed sensor (VS), a torque sensor (TR), etc. which output digital values.
The respective output of the previously-mentioned analog sensors are A/D converted for each of the kinds of controls to be used for controlling. That is, for example, since the output of the water temperature sensor (TW) is used for engine control as well as for car-cooler control, it has been necessary to provide two A/D converters for the respective controls.
Thus, in a conventional electronic car-control system, there have been provided individual input processing devices for the respective controls with a drawback that the circuit of the system becomes excessively large and large number of circuit elements are required.