Nippon Soken, Inc.

Ritsu Katsuoka

Hisasi Kawai

Seiji Morino

Kazuo Iwase

Ignition timing control for an internal combustion engine is achieved by sensing engine rotation so as to generate output pulses for predetermined degrees of rotation and to develop a reset pulse at a rotational reference position. A first digital signal representing rotational speed of the engine and a second digital signal representing engine intake vacuum are converted into output date representative of optimum retard angles from the reference position. The output date are added to generate a plural bit binary signal having higher and lower significant bits. Comparison means, responsive to the reset pulse, counts the output pulses representing degrees of engine rotation and generates an output signal when the count reaches the value of the higher significant bits. Additional comparison means, responsive to the output signal from the first mentioned comparison means, counts multiplied output pulses representing degrees of engine rotation and generates an output signal representing optimum ignition time when the count reaches the value of the lower significant bits.

Electronic ignition timing control system for internal combustion engine

A logarithmic function generating system which generates an output signal bearing a logarithmic functional relation to the input signal. The time constant RC of a resistance-capacitance circuit is increased for every unit time elapsed in proportion to the unit time to produce a broken line approximating the logarithmic function. With its simple circuit construction employing no elements whose characteristics vary with ambient temperature changes or which tend to involve variations in characteristics among the elements of the same type, the system is capable of generating the desired logarithmic function output with a high degree of accuracy.

Logarithmic function generating system

There is provided an electronically controlled fuel injection system wherein a constant presetting circuit generates a proportionality constant signal having a frequency corresponding to a proportionality constant, an intake-air amount detecting circuit generates a binary coded signal corresponding to the amount of air drawn into an internal combustion engine, and a multiplier circuit multiplies the proportionality constant signal by this binary coded signal and generates an output signal having a frequency corresponding to the product of the two signals. On the other hand, an engine revolution detecting circuit generates an engine revolution signal having a pulse width inversely proportional to the number of revolutions of the engine, and the number of multiple signals generated from the multiplier circuit during the pulse width of the engine revolution signal is counted to generate a binary coded signal representing the fuel injection quantity required by the engine. A converter circuit generates a pulse signal having a time width corresponding to the binary coded signal representing the required fuel injection quantity and the pulse signal is used to operate fuel injection valves.

Electronically controlled fuel injection system

A digital logarithmic function generator comprising a converter circuit for producing an output signal which is proportional to the number of input signals, a setting circuit the content n of which is changed each time the output voltage of said converter circuit changes by a fixed amount Vo, and a modulator circuit for frequency modulating a clock signal train of a constant frequency with said content n to produce an output signal train the period of which varies proportionally with 2.sup.nVo, the output signal train of said modulator circuit being applied to said converter circuit as the input signal thereto. The present digital logarithmic function generator is useful in various control systems, such as an electronically controlled fuel injection system, in which an electrical signal which is logarithmically related to time is required.

Digital logarithmic function generator

A fuel injection controlling system for an internal combustion engine comprising an oscillator circuit for generating clock pulses having a frequency corresponding to the air-to-fuel ratio of the mixture, a first detecting circuit for generating pulse signals having a time width corresponding to the rate of air flow to the engine, a first multiplier circuit for generating an output corresponding to the product of the air-to-fuel ratio and the rate of air flow in a binary coded form, a second detecting circuit for generating signals having a pulse width proportional to the rotational speed of the engine, a second multiplier circuit for generating an output corresponding to the product of the air-to-fuel ratio and the rate of air flow and the rotational speed of the engine in a binary coded form, and a conversion circuits for generating pulse signals each corresponding to the output of the second multiplier circuit, whereby fuel injection valves are actuated by the output of the conversion circuit.

Fuel injection controlling system for an internal combustion engine

A digital hyperbolic function generator comprises a frequency dividing circuit for frequency dividing first clock signals of a fixed frequency to produce second clock signals for each fixed time interval, a setting circuit for changing the setting thereof in correspondence to the number n of said second clock signals, said setting being produced in a binary code, a modulating circuit for frequency modulating said first clock signals with said setting to produce third clock signals the period of which is proportional to ##EQU1## AND A CONVERTER CIRCUIT FOR PRODUCING A VOLTAGE CORRESPONDING TO THE NUMBER OF SAID THIRD CLOCK SIGNALS. The digital hyperbolic function generator thus constructed generates a hyperbolic function of polygonal line approximation the gradient of which changes for each fixed time interval with a high accuracy, and the operation thereof is stabilized against the change in ambient temperature because the circuits are constructed by digital elements.

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Okazaki, Japan

Ritsu Katsuoka