Nissan Motor Company Limited

Hicachi, Ltd.

Shigeo Aono

Akio Hosaka

Masaharu Asano

Takeshi Fujishiro

Makoto Anzai

Nobuzi Manaka

Mituhiko Ezoe

Kenji Masaki

Kenji Ikeura

Sadao Takase

Yoshitaka Hata

Haruto Tanaka

Kokichi Ochiai

Michiyoshi Yamane

Hiroshige Ozawa

Hiromichi Nakamura

Norio Mizuguchi

Masahara Asano

The present invention features a control system for controlling the combustion process occurring in the combustion chamber of an internal combustion engine, wherein the exact nature of the combustion pressure generation wave form occurring during a compression and subsequent expansion stroke is determined via determining the nature of the motoring pressure wave during the same compression and expansion strokes and discriminating this form from the actual sensed pressure generation characteristics. The system further permits the effect of various operational parameters such as exhaust gas recirculation, ignition timing, air fuel ratio and the like on the combustion process and therefore on the torque output, fuel consumption and noxious emission levels of the engine, to be predicted and compared with predetermined schedules in order to determine the degree to which adjustment of one or more of the above mentioned operational parameters is necessary to bring the engine performance characteristics into agreement with predetermined requirements.

Control arrangement for internal combustion engine

In order to determine the exact nature of the combustion process occuring within the combustion chamber of an internal combustion engine, the timing is retarded to the point where no combustion pressure is produced during the compression stroke of the piston. This allows the compilation of the pressure history of the first half of the motoring pressure wave produced by the movement of the piston, the subsequent mathematical derivation of the essentially symmetrical second half of the wave and the determination of the exact nature of the combustion pressure generation. This of course facilitates combustion process control via indicating the effects of exhaust gas recirculation, ignition timing, air fuel ratio and the like, on the combustion time, heat generation and peak combustion pressure of the combustion phenomenon.

Method for discriminating motor/combustion pressures in an I.C.E.

The present invention features a method of calibrating a pressure sensor disposed in an internal combustion engine which is characterized by delaying the ignition until combustion pressure is not generated during the compression stroke, recording the pressure history and mathematically deriving the essentially symmetrical half of the motoring pressure wave which occurs within the combustion chamber during the expansion stroke thereby obtaining the total motoring pressure history irrespective of the generation of combustion pressure. This data permits the output of the pressure sensor to be frequently compared with predetermined motoring pressure values for the same amount of inducted air and thus the value assigned to the output of the sensor to be adjusted to allow for the physical changes which occur within the sensor with temperature and age.

Method of calibrating pressure sensor

An engine idling speed control system for an internal combustion engine which controls engine idling speed by adjusting the amount of intake air by-passing the throttle valve on the basis of the air-to-fuel ratio, in addition to the difference between the actual idling speed and the optimum idling speed determined on the basis of engine coolant temperature. The system according to the present invention comprises an air-to-fuel ratio determination section and an intake air calculation section for calculating the basic amount of intake air on the basis of the difference between the idling speed and the optimum idling speed and correcting the calculated basic amount of intake air on the basis of the air-to-fuel ratio.

Idling speed control system for internal combustion engine

A method and system for correcting engine ignition timing without the use of any pressure sensor or vibration sensor and depending upon engine knocking is disclosed. The presence or absence of knocking is determined by reference to the rate of change of engine speed. This method is based on the fact that engine speed changes abruptly when engine knocking occurs, as compared with the normal engine condition, because of abrupt changes in pressure within the cylinders. The system of the present invention comprises an crankshaft angle sensor to generate a crankshaft angle pulse signal, a period measuring means to output an interrupt request signal and to determine the presence or absence of engine knocking, a microcomputer, and an ignition signal generator for outputting an ignition signal in accordance with an ignition timing signal and a dwell angle signal.

Method and system for controlling engine ignition timing

Emission control apparatus for a multi-cylinder internal combustion engine has an exhaust composition sensor disposed in a passage in common to the exhaust systems of the engine. The sensed concentration of the exhaust composition is modulated in amplitude by a bipolar pulsating signal at a frequency higher than the frequency of the sensed exhaust concentration. A statistical analysis indicates distribution of the ratios within a narrow stoichiometric window.

Emission control apparatus for internal combustion engines using an

A data gathering system is disclosed for use with an automotive vehicle. The system includes an A/D converter for converting an input analog value into a corresponding digital value, a multiplexor having a number of data channels for transferring vehicle operation variable indicative analog values to the A/D converter when rendered conductive, and a digital computer for selectively rendering the data channel conductive in a predetermined sequence. The digital computer is adapted to correct the converted values according to supply voltage variations and store the corrected values therein.

Data gathering system for automotive vehicles

Mixture ratio control for internal combustion engines supplies a constant current into an exhaust gas sensor to develop a voltage of a substantial magnitude in proportion to the initial high value of the gas sensor internal impedance during low temperature conditions. The voltage so developed decreases as a function of time corresponding to the decrease of the internal impedance with temperature. A voltage detector is provided to trigger the control system to operate in a closed loop mode when the gas sensor voltage is reduced to a level below a first threshold level. Responsive to the output of the voltage detector the supplied current is momentarily interrupted to allow the gas sensor voltage to drop rapidly to a level which is higher or lower than a second threshold level depending on the concentration of the sensed gas in the exhaust system. A second detector senses this voltage drop relative to the second threshold to determine whether the gas sensor output represents rich or lean condition. The reference point of the closed loop is raised or lowered in response to the output of the second detector and further decreased as a function of time such that the reference point lies within the range between maximum and minimum peak values of the gas sensor output signal.

Variable reference mixture control with current supplied exhaust gas

In an electronic fuel injection system for an internal combustion engine, a throttle position sensor provides an output pulse with a duration corresponding to the time interval during which throttle is nearly closed. The output from the throttle position sensor is nullified when the pulse duration is smaller than a predetermined value to prevent fuel cut-off during brief closure of throttle during transmission gear changes. The output from the throttle position sensor is used to cut off fuel only when the throttle closure time extends beyond the predetermined time interval.

Electronic fuel injection with means for preventing fuel cut-off during

A circuit is provided in an electronic closed loop air-fuel ratio control system for starting and terminating the operation of the system at different voltages from an exhaust gas sensor.

Electronic closed loop air-fuel ratio control system for use with

A closed-loop emission control apparatus for internal combustion engines includes an exhaust composition sensor disposed at the upstream side of a catalytic converter which converts the noxious exhaust components into harmless products at the highest efficiency when the air-fuel ratio is controlled at a value in the vicinity of stoichiometry in accordance with a control signal derived from the sensed concentration of the exhaust composition. The output from the exhaust composition sensor is utilized to generate an offset voltage by averaging the instantaneous values of the sensed concentration, the offset voltage being combined with the control signal to cancel an error introduced thereinto during use of the apparatus.

Closed-loop emission control apparatus for internal combustion engine

A closed loop fuel control system for an internal combustion engine having in its exhaust system an exhaust composition sensor generating a signal indicative of air-fuel ratio in gases in the exhaust system and an integral controller providing integration on the generated signal for adjusting the ratio of air and fuel supplied to the engine, and a storage device which stores the output from the controller in response to a sensed particular engine operating parameter. The stored signal is later extracted in response to the sensing of the same engine operating parameter to rapidly vary the controller output.

Closed loop fuel control with sample-hold operative in response to

In a feedback control system for maintaining the air-fuel ratio of a combustible mixture fed to an internal combustion engine at a preset ratio, a fluctuation in the output characteristic of an exhaust sensor due to deterioration or low temperature is compensated for by varying a reference voltage, which serves as a standard of comparison, in response to a change in the mean value of the sensor output voltage.

Compensation for inherent fluctuation in output level of exhaust sensor

Emission control apparatus for internal combustion engines is provided with a sensor for detecting the concentration of a particular exhaust composition in the emissions from the engine. A signal indicating the deviation of the mixture ratio from a controlled point is generated by comparing the output from the sensor with a reference level, the signal being modified in amplitude according to a predetermined control characteristic and used to regulate the air-fuel mixture ratio at the desired control point. The varying magnitude of the sensed concentration is smoothed into a signal of slowly varying magnitude which is used to control the reference level so that error introduced into the deviation indicating signal due to the change with time in the output performance of the exhaust composition sensor is self-compensated. A level sensor is provided to detect when the reference level reaches an end of the control range to change the operating mode of the engine from closed-loop to open-loop mode.

Feedback emission control for internal combustion engines with variable

The spark advance control apparatus of the invention comprises a vacuum advance control mechanism and a speed advance control circuit. The vacuum advance control mechanism senses the vacuum pressure in the intake manifold of an internal combustion engine and generates an electrical pulse in advanced timing in relation to the sensed vacuum. The speed advance control circuit receives the pulse from the vacuum advance control mechanism, converts it into a voltage signal representative of the revolution of the engine crankshaft and generates an output voltage which varies nonlinearly as a function of the voltage signal. A pulse-width generator is provided having a first input connected to receive the pulse from the vacuum advance control mechanism and a second input connected to receive the nonlinear speed related voltage signal to generate a pulse which commences in response to the vacuum advance pulse and ends at a time determined by the speed related voltage signal. The trailing edge of the output from the pulse-width converter is utilized for ignition.

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Seki, Japan

Shigeo Aono