Abstract: A vehicular communication device includes a plurality of request switches, a request signal generator means, a transmitter, a receiver and a display. The request switches respectively designate a plurality of services which a user may request. The request signal generating means checks the operational conditions of all request switches in order to enable the user to operate at least two of the request switches substantially simultaneously. The request signal generator then generates a request signal on the basis of the checking. The transmitter transmits the request signal to a remote service facility. The receiver receives an acknowledgment signal received signal transmitted from the service facility. The display displays a message in accordance with the acknowledgment signal for assuring the user that the request signal has been received by the service facility.

Abstract: A brake apparatus for use in a motor vehicle having at least one front wheel and at least one rear wheel. The brake apparatus includes a diagonal braking pressure supply system provided between a master cylinder and wheel braking cylinders for applying braking forces to the front and rear wheels. A proportioning valve is provided in the braking pressure supply system for controlling the braking pressure to be applied to the rear-wheel braking cylinder in accordance with a control signal so as to vary the ratio of the braking pressure to the rear-wheel braking cylinder with respect to the braking pressure to be applied to the front-wheel braking cylinder. Also included is an electronic control unit which produces the control signal to the proportioning valve.

Abstract: In a braking apparatus for use in a motor vehicle which supplies hydraulic pressure from a master cylinder to wheel braking cylinders for front-side and rear-side wheels, a braking force adjusting device is provided in common between the master cylinder and the front-side and rear-side wheel braking cylinders to adjust the hydraulic pressure to be applied to the front-side and rear-side wheel cylinders. A proportioning valve controls the hydraulic pressure to the rear-side wheel braking cylinder to become lower than the hydraulic pressure from the braking force adjusting device by a predetermined ratio. The proportioning valve is adapted to change the predetermined ratio in accordance with a control signal to prevent the rear-side wheel from locking. The control signal to the proportioning valve is determined on the basis of information representing an excessive degreee of braking force obtained in accordance with the states of the front-side and rear-side wheels during the braking operation.

Abstract: A speed control system for a motor vehicle automatically controls a throttle valve so as to allow the vehicle to run at a desired velocity at all times. The system includes a laser radar for detecting a preceding vehicle and measuring the distance therefrom, and a control computer in which a proper distance responsive to a vehicle velocity is set. The control computer discriminates proximity to the preceding vehicle through change in the distance at a certain interval. When the distance exceeds the proper distance, the control computer reduces the desired velocity in case proximity to the preceding vehicle is discriminated at a plurality of times continuously and increases the desired velocity in case no such proximity is discriminated, and when the distance is below the proper distance, the computer decelerates the vehicle by directly controlling the throttle valve in the closing direction, allowing tracing running with the proper distance from the preceding vehicle.

Abstract: A speaker changeover device has a plurality of audio equipments for outputting ready condition signals when the power source is turned on; a speaker which is used by the audio equipments in common, a changeover control circuit which starts its operation by turning a cycle start switch, cyclically monitors the ready condition signals from the audio equipments simultaneously with the input of clock signals and generates a changeover signal to the audio equipment which first outputs the ready condition signal to stop its operation, and an electromagnetic relay operated by the changeover signal to connect the audio equipment which first outputs the ready condition signal, to the speaker.

Abstract: An obstacle monitoring device for the rear of a vehicle comprising a plurality of ultrasonic obstacle detectors which are operated sequentially at a predetermined time interval, and an electronic monitor for supplying the obstacle detectors with their operational timing sequences at the predetermined time intervals and for determining distance information for each detector based on the changing pulse width of electric currents for each of the obstacle detectors within a particular time interval, which pulse widths correspond to the distance between an obstacle and the rear of the vehicle. A single transmission line connects the obstacle detectors with the monitor so that the number of wires in a wire-harness is reduced between the obstacle detectors (outside the vehicle) and the monitor (inside the vehicle).

Abstract: An overdrive control apparatus is provided with a gradient sensor unit for sensing a gradient of a vehicle running road. The overdrive control apparatus releases an overdrive mode of an automatic change gear device which is set up for a level drive of the vehicle in accordance with a sensing signal from the gradient sensing unit.

Abstract: An automotive rear safety checking apparatus which comprises a plurality of obstacle detectors mounted on the rear part of the automobile for radiating ultrasonic wave on the watching areas smaller in width than the width of the automobile respectively and detecting the ultrasonic wave reflected from an obstacle. The ultrasonic wave is radiated from the obstacle detectors in time division. Pulse signals in the number associated with the distance between the obstacle detector and the obstacle are generated in response to the detection of the ultrasonic wave reflected from the obstacle, so that the relative positions of the automobile and the obstacle, are indicated two-dimensionally in accordance with the pulse signal.

Abstract: A rear obstacle detecting system for automotive vehicles includes an ultrasonic transmitter/receiver unit, distance detecting unit and an indicator for measuring distance to an obstacle while a vehicle is in backward movement. The ultrasonic transmitter/receiver unit having a ultrasonic vibrator is always energized as long as the vehicle is in an operating condition irrespective of whether the vehicle is in a backward movement or not, in order to maintain the ultrasonic vibrator being vibrated to achieve a self-cleaning function. The indicator is energized only when the vehicle is in backward movement.

Abstract: Two hermetically sealed chambers alternately hold the atmospheric pressure in response to a timing pulse generated each time a vehicle travels a predetermined distance. The difference between the atmospheric pressures held in the sealed chambers is detected by a semiconductor pressure sensor disposed between the sealed chambers. Two sample and hold circuits alternately sample and holds the detection output of the semiconductor pressure sensor in response to the timing pulse. A comparison circuit compares the hold outputs of the sample and hold circuits to generate an output corresponding to the difference or the grade of the vehicle. If necessary, the output of the comparison circuit is converted to a pulse signal having a pulse time width corresponding to the output.

Abstract: An apparatus measures and indicates the speeds of a vehicle at the beginning and end of braking of the vehicle by counting as many vehicle speed representative pulse signals as indicative of the speed per hour of the vehicle which are gated during the time that the desired number of clock pulses are counted in response to the beginning and end of braking of the vehicle, respectively.

Abstract: An altitude difference measuring apparatus for measuring the difference between the altitudes at a first and second points on the basis of the barometric difference between the points, having an air pressure holding section with an electromagnetic valve for hermetrically containing an amount of air. At the first place an amount of the ambient air is held hermetrically in the air pressure holding section, and at the second place the barometric difference between the air pressure in the air pressure holding section and the ambient air pressure is converted into an electric signal, and in accordance with the electric signal the difference between the altitudes at the first and second points is indicated.

Abstract: First and second sample-hold circuits sample and hold the atmospheric pressure alternately every time when a vehicle travels a predetermined distance. A signal representing a difference between the holding values of the first and second sample-hold circuits, that is, a signal representing a slope of the road on which the vehicle is travelling is displayed through a latch circuit.