Abstract: In order to determine the contents of a tank fitted with liquid level sensors and metering equipment, a microprocessor is programmed with an algorithm employing a mathematical expression for initially computing data value based on liquid level sensor outputs and tank dimensions, which data values are compared with actual volumetric amounts of liquid in the tank derived from the metering equipment so as to determine errors in a calibration characteristic for converting the sensor outputs into volumetric amounts. The calibration characteristic is refined by an iterative technique where constants in the mathematical expresson are varied, in accordance with the program so as to make the computed data values closer to the actual volumetric amounts derived from the metering equipment for respective liquid levels in the tank.

Abstract: A tachograph comprises a casing (1,2) which houses a speed indicator (4), an odometer (6) and styli (8a, 8b) for respectively recording speed and distance travelled. A stepper motor (22) drives the speed indicator (4) and speed recording stylus (8a). A stepper motor (23) drives the odometer (6) and distance recording stylus (8b). A pulse generator (25) provides an input, proportional to vehicle speed, to a microprocessor (16) which computes speed and distance on the basis of the pulse input and a correction factor (26) relating to vehicle characteristics in order to drive the stepper motors (22,23). The microprocessor (16) is also responsive to a preset maximum top speed reference (27) and a driver selected top speed reference (28) to provide an output to an actuator (30) in order to control the vehicle speed.

Abstract: A tachograph includes stylus recorder (4,5,6) responsive to a signal related to engine speed for recording an indication of the engine speed on a chart (1). The stylus recorder is conditioned to provide a bar trace having different and readily distinguishable levels. Each level represents a threshold of engine speed which indicates that the engine speed is at or below the respective threshold and within a predetermined range. Threshold selector (8 or 9) are provided for adjusting the relationship between the levels and the predetermined thresholds so that the bar trace levels stay substantially the same but represent engine speed thresholds which are adjustably predetermined by the threshold selector.

Abstract: The speed control actuator can be used to modify a control linkage fitted between an accelerator pedal and a carburetor or fuel injection pump on a vehicle engine. The actuator includes a forked lever which is mounted for rotation on the shaft of the fuel regulator, and a pulley which is mounted for rotation relative to the forked lever. The accelerator pedal is connected by means of a cable to the forked lever. Another cable passes over the pulley and is connected to a microprocessor controlled cable drive. The cable is advanced and retracted, in accordance with a vehicle speed related signal, to adjust the fuel regulator independently of the accelerator pedal. A preferred form of drive means is also described which employs a microprocessor producing a speed-related output in the form of a pulsating current of one polarity or another, and having a variable mark-to-space ratio, for driving a dc motor coupled to the actuator.