Lucas Industries Limited

Other

John P Southgate

Malcolm Williams

Steven J Russell

Albert R Tingey

William F Hill

Richard G Woodhouse

Christopher J Rainey

Cyril Endfield

Computer apparatus comprising a central computer having a data input port, means connecting two or more remote chord keyboards to the input port, and means for identifying with each respective keyboard alpha-numeric and like character data and command instructions generated by operation thereof and received through the input port; the central computer is programmed to process and combine the character data from the keyboards in accordance with the commands and to output resultant information for display in common by video and/or audio display means. In a preferred embodiment key-operated switches incorporated in each remote chord keyboard are connected in an R-2R resistive ladder network so that operation thereof either singly or in combinations of two to all will produce ratiometric changes in an analog output voltage that uniquely varies as the binary weighting of the operated switch or switch combination. An analog-to-digital converter is connected to the input port of the computer to translate the signals generated at the remote chord keyboard to a form that can be handled by the central processing unit of the central computer.

Computer apparatus and remote keyboards therefor

An electronic fuel injection control includes a main fuel control circuit, a transient enrichment control circuit temporarily increasing fuel flow as a result of increasing of a demand signal, and temperature compensation means non-linearly varying the effect of the enrichment control with engine temperature. The temperature compensation means preferably includes a temperature 'window' detector which acts to increase the effect of the enrichment control whenever the engine temperature is between prescribed limits.

Internal combustion engine

A solenoid drive circuit includes two output transistors in parallel paths of relatively high and low resistance respectively. The low resistance path transistor is controlled by a voltage comparator arranged to compare the voltage across a common current sensing resistor with a reference voltage. When the input to the circuit is low, the high resistance path transistor is biased on, but where the current is below a set level, only the low resistance path transistor conducts. Only when the comparator changes state as the solenoid current exceeds its set level does switching off of the low resistance path transistor permit the other transistor to turn on. A delay circuit is included which operates to prevent the low resistance path transistor turning on if there is a short circuit across the solenoid.

Solenoid drive circuits

An electronic fuel injection control includes a main fuel control circuit which operates to control fuel flow to the engine by controlling the duration of engine-synchronized fuel valve opening pulses in accordance with at least one engine parameter. An auxiliary pulse source is arranged to provide extra unsynchronized pulses to improve the acceleration characteristics of the control, such pulses being produced when the throttle is opened. A muting circuit is provided which operates for a fixed period following closing movement of the throttle, to prevent the auxiliary pulse source responding to throttle opening during said period. The muting circuit prevents excess fuelling during gear changes etc.

Fuel injection systems

An internal combustion engine function control system, for example a spark ignition control system, comprising first and second pulse generating means driven by the engine. The first pulse generating means produces a train of pulses at a first frequency equal to the frequency of the required function and the second pulse generating means produces a train of pulses at a second frequency which is a multiple of the first frequency. Engine parameter sensitive means are provided for varying the phase of the second pulse train relative to that of the first pulse train between limits such that the combined ordinal succession of the pulses is maintained constant. The system further includes function timing means for causing triggering of an output circuit at the end of a delay following a pulse from said first pulse generating means. This delay consists of the sum of a first delay to one of the pulses produced by the second pulse generating means and a second delay, the first and second delays being determined by the frequency and phase of the two pulse trains.

Internal combustion engine function control system

An electronic fuel injection control includes a main control circuit which controls fuel flow to the engine by controlling the duration of pulses applied to fuel valves. In addition there is a transient fuel varying control including a differentiating circuit which differentiates the signal from a throttle position transducer. This differentiator controls a variable frequency clock which forms part of the main fuel control so that the pulse duration is lengthened or shortened for a given value of the engine parameter which controls the main fuel control according to the rate of increase or decrease of the throttle position signal.

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Coventry, United Kingdom

John P Southgate