Analog computer, particularly for an ignition system for internal combustion engine

Claim 2

An analog computer, suitable for providing control signals in an internal combustion engine, said computer comprising in combination: a. signal synthesizer circuit means for generating a continuous ignition advance angle signal as a function of engine rotation speed over a predetermined speed range and of air intake pressure in accordance with a predetermined response characteristic, said synthesizer means comprising transconductance amplifier stages for generating signals corresponding with respective segments of said response characteristic and means for summing outputs from said amplifier stages to generate said continuous signal; and b. circuit means for controlling the instant of commencement of a control signal output from said computer with respect to a reference time, as a function of the instantaneous speed of engine rotation and of the instantaneous value of said ignition advance angle signal.

Claim 3

An analog computer according to claim 1, wherein said transconductance amplifier stages comprise: a series of first stages for synthesizing electric current signals corresponding with segments of a curve representing variations of ignition advance angle as a function of said engine speed of rotation within respective predetermined intervals of said engine speed range; and a second stage for generating an electric current signal corresponding with a curve representing variation of said ignition advance angle as a function of said air intake pressure; and said means for summing outputs from said first and second stages to generate said continuous ignition advance angle signal comprising electric current summation means.

Claim 4

An analog computer according to claim 2, further including means for generating, for each of said first stages, a reference voltage corresponding to the mid-point of the said curve segment to be synthesized by the output signal of said stage.

Claim 5

An analog computer according to claim 2, wherein said current summing means includes a current mirror circuit.

Claim 6

An analog computer according to claim 1, wherein said circuit means controlling the instant of commencement of said control signal output comprises current generator means for generating a current proportional to the speed of engine rotation connected to a resistance-capacitance circuit for storing energy necessary for initiating commencement of said control signal output when the energy stored by said resistance-capacitance circuit produces a voltage across the capacitance of said resistance-capacitance circuit corresponding to said ignition advance angle signal.

Claim 7

An analog computer according to claim 6, wherein said circuit for controlling the instant of commencement of said control signal output includes switch means connected to short-circuit said capacitance at a predetermined instant in the operating cycle of said engine corresponding to said reference time.

Claim 8

An analog computer according to claim 1, further including circuit means for inhibiting said control signal output after a predetermined time interval.

Claim 9

In an internal combustion engine including an ignition system operated by control pulses and wherein the ignition angle is dependent upon the instantaneous speed of rotation of said engine and on the instantaneous air intake pressure of said engine, an analog computer circuit for generating said control pulses comprising, in combination: a. signal synthesizer circuit means for generating a continuous ignition advance angle signal as a predetermined function of engine rotation speed over a predetermined engine speed range and of air intake pressure, said synthesizer circuit means comprising a plurality of first transistor transconductance amplifier stages for synthesizing output signals representing variations of ignition advance angle as a function of said engine speed of rotation over predetermined discrete intervals of said engine speed range; a second transistor transconductance amplifier stage for generating an output signal corresponding with variation of said ignition advance angle as a function of said air intake pressure; and a transistor summation circuit for summing said output signals from said first and second stages to generate said continuous ignition advance angle signal; and b. transistor circuit means for controlling the instant of commencement of a control pulse from said computer with respect to a reference time as a function of the instantaneous speed of engine rotation and of the instantaneous value of said ignition advance angle signal, said transistor circuit means comprising current generator means for generating a current proportional to the speed of engine rotation connected to a resistance-capacitance circuit for storing energy necessary for initiating commencement of a said control pulse when the energy stored by said resistance-capacitance circuit produces a voltage across the capacitance of said resistance-capacitance circuit corresponding to said instantaneous ignition advance angle signal.

Claim 10

In an internal combustion engine including an ignition system operated by control pulses and wherein the ignition angle is dependent upon the instantaneous speed of rotation of said engine and on the instantaneous air intake pressure of said engine, an analog computer circuit for generating said control pulses comprising, in combination: a. signal synthesizer circuit means for generating a continuous ignition advance angle signal as a predetermined function of engine rotation speed over a predetermined engine speed range and of air intake pressure, said synthesizer circuit means comprising a plurality of first transistor transconductance amplifier stages for synthesizing output signals representing variations of ignition advance angle as a function of said engine speed of rotation over predetermined discrete intervals of said engine speed range; a second transistor transconductance amplifier stage for generating an output signal corresponding with variation of said ignition advance angle as a function of said air intake pressure; and a transistor summation circuit for summing said output signals from said first and second stages to generate said continuous ignition advance angle signal; and b. transistor circuit means for controlling the instant of commencement of a control pulse from said computer with respect to a reference time as a function of the instantaneous speed of engine rotation and of the instantaneous value of said ignition advance angle signal, said transistor circuit means comprising current generator means for generating a current proportional to the speed of engine rotation connected to a resistance-capacitance circuit for storing energy necessary for initiating commencement of a said control pulse when the energy stored by said resistance-capacitance circuit produces a voltage across the capacitance of said resistance-capacitance circuit corresponding to said instantaneous ignition advance angle signal.

Claim 11

An analog computer according to claim 8, further including means for generating for each of said first and second stages, respective reference voltages, each corresponding to the mid-point of a discrete interval of said engine speed range to be synthesized by the output signal of said stage.

Claim 12

An analog computer according to claim 8, wherein said means for summing outputs from said first and second stages includes a transistor current mirror circuit.

Claim 13

In an internal combustion engine including an ignition system operated by control pulses and wherein the ignition angle is dependent upon speed of rotation of said engine and air intake pressure of said engine, an analog computer circuit comprising in combination: a. signal synthesizer circuit means for generating a continuous ignition advance angle signal as a predetermined function of engine rotation speed over a predetermined engine speed range and of air intake pressure, said synthesizer means comprising transconductance amplifier stages for generating output signals corresponding to respective segments of said engine speed range and means for summing said output signals from said amplifier stages to generate said continuous signal; b. circuit means for controlling the instant of commencement of a control pulse from said computer with respect to a reference time as a function of the instantaneous speed of engine rotation and of the instantaneous value of said ignition advance angle signal, said circuit means comprising current generator means for generating a current proportional to the speed of engine rotation connected to a resistance-capacitance circuit for storing energy to generate a voltage for initiating commencement of a said control pulse when the energy stored by said resistance-capacitance circuit produces a voltage across the capacitance of said resistance-capacitance circuit corresponding to said ignition advance angle signal, and electrical switch means for short-circuiting said capacitance at a predetermined instant in each operating cycle of said engine corresponding to said reference time thereby inhibiting said control pulses such that said computer generates constant duration control pulses.

Claim 14

In an internal combustion engine including an ignition system operated by control pulses and wherein the ignition angle is dependent upon speed of rotation of said engine and air intake pressure of said engine, an analog computer circuit comprising in combination: a. signal synthesizer circuit means for generating a continuous ignition advance angle signal as a predetermined function of engine rotation speed over a predetermined engine speed range and of air intake pressure, said synthesizer means comprising transconductance amplifier stages for generating output signals corresponding to respective segments of said engine speed range and means for summing said output signals from said amplifier stages to generate said continuous signal; b. circuit means for controlling the instant of commencement of a control pulse from said computer with respect to a reference time as a function of the instantaneous speed of engine rotation and of the instantaneous value of said ignition advance angle signal, said circuit means comprising current generator means for generating a current proportional to the speed of engine rotation connected to a resistance-capacitance circuit for storing energy to generate a voltage for initiating commencement of a said control pulse when the energy stored by said resistance-capacitance circuit produces a voltage across the capacitance of said resistance-capacitance circuit corresponding to said ignition advance angle signal, and electrical switch means for short-circuiting said capacitance at a predetermined instant in each operating cycle of said engine corresponding to said reference time thereby inhibiting said control pulses such that said computer generates constant duration control pulses.

Claim 15

An analog computer according to claim 11, wherein said circuit means for controlling the commencement of a said control pulse comprises first and second comparator circuit means for receiving said ignition advance angle signal as a first input and a signal dependent on said current proportional to the speed of engine rotation as a second input, an AND gate having inputs connected to outputs of said first and second comparators such that said AND gate is enabled when said voltage across the capacitance of said resistance-capacitance circuit corresponds to said ignition advance signal thereby causing commencement of a said control pulse; and said electrical switch means connected to short-circuit said capacitance causes disablement of said AND gate and termination of that said control pulse at said predetermined instant in the operating cycle of said engine.

Claim 16

An analog computer as set forth in claim 12, including a resistor connected in series with said capacitor and wherein the duration of said control pulse is determined by the time constant of said series connected resistor and capacitor.

Claim 17

An analog computer as set forth in claim 12, wherein each of said comparators includes a transistor differential amplifier including a current mirror circuit.

Claim 18

An analog computer as set forth in claim 12, wherein said AND gate output is connected to control operation of an output current amplifier.

Claim 19

An analog computer as set forth in claim 11, wherein said signal synthesizer circuit means comprises a plurality of first transistor transconductance amplifier stages for synthesizing output signals representing variations of ignition advance angel as a function of said engine speed of rotation over said respective segments of said engine speed range; a second transistor transconductance amplifier stage for generating an output signal representing variation of said ignition advance angle as a function of said air intake pressure; and transistor means for summing output signal from said first and second stages to generate said continuous ignition advance angle signal.

Claim 20

An analog computer as set forth in claim 16, wherein said means for summing output signals from said first and second stages includes a transistor current mirror circuit.