Abstract: An engine control apparatus has an air flow rate measuring device for measuring an intake air flow rate. A temperature sensing element having a temperature characteristic and constituting the device is arranged in an intake pipe. The device generates an output pulse signal having a pulse width T corresponding to the intake air flow rate. An engine control unit has the one-dimensional map for storing the relationship between the engine speed N and the pulse width to of the signal corresponding to the air flow rate. This data to is read out from the one-dimensional map in accordance with the engine speed N. Subsequently, the data to is subtracted from the data T to calculate a time duration t. The unit also has a two-dimensional map for storing the relationship between each time duration t and the corresponding rate G/N in correspondence with each of the present engine speeds. A corresponding rate G/N is read out from the two-dimensional map in response to the calculated time duration t.

Abstract: A potentiometer chamber on the intake pipe wall of an internal combustion engine for containing an electrical potentiometer. The potentiometer chamber comprises a limiting wall, formed by the intake pipe wall, a sidewall extends thereto from which serves as lateral limits of the chamber. A partition made by injection molding from plastic, into which are embedded electrical contacts extends from the sidewall and a lid is placed on the partition. Therefore the limiting wall, the sidewall, the partition, and the lid form the chamber that encloses a potentiometer.

Abstract: In a diesel engine control system, an intake air density compensation system is provided for compensating the control amounts of a diesel engine in accordance with the variations of intake air density. The variation amount of the intake air density is indicated by the difference between the control input amount obtained in accordance with an ignition timing closed loop control and the control amount obtained in accordance with an ignition open loop control. The various control amounts of the diesel engine is compensated on the basis of the difference so that the diesel engine is ensured to be optimally operated irrespective of the variations of intake air density.

Abstract: A fuel injection detecting system is used with a diesel engine having a fuel injection nozzle, the nozzle including a movable member for effecting fuel injection into the engine when the valve member is displaced from its normal position and interrupting fuel injection when the valve member is returned to its normal position. The detecting system includes a sensor for sensing displacement of the valve member and generating a signal indicative thereof. A comparator is provided to compare the signal from the sensor with a reference signal and to generate a signal indicative of fuel injection via the nozzle. The detecting system also includes a device for preventing the fuel injection signal from including components unrelated to fuel injection via the nozzle. This device may disable the sensor for a predetermined period immediately after the first major displacement of the valve member.

Abstract: The invention is directed to a correcting arrangement for a fuel metering apparatus of an internal combustion engine by means of which permanent offsets of the positioning control loop of the fuel metering apparatus of the internal combustion engine are corrected. This is accomplished in that at a specific load condition of the internal combustion engine, preferably in the overrun mode of operation subsequent to the idle speed control characteristic, the actually injected fuel quantity which is a diesel engine, for example, is preferably measured by means of the movement of the nozzle needle of the injection valve of the fuel metering apparatus, is checked to a known value, in the example cited preferably for zero value, and in that the result of this check is used to influence the control system of the fuel metering apparatus of the internal combustion engine.

Abstract: A system for measuring the air flow into the engine over the full operating range thereof is described employing a pair of air flow measuring concepts selectively enabled dependent upon engine operation so as to accurately achieve a measurement of air flow over the full range of engine operation.

Abstract: A stream of water or a water-methanol mixture is injected into the induction passage of a spark ignition internal combustion engine, and a probe disposed in the induction passage is contacted by the stream to sense when the density of the engine charge can be increased, the air-fuel ratio of the engine charge can be leaned and the timing of ignition of the engine charge can be advanced beyond normal operating ranges.

Abstract: A method for detecting the ignition timing for an engine comprising the steps of detecting the production in a crank angle range outside of the range where ignition can occur of a crank angle signal by a crank angle sensor at a first time point, detecting an ignition signal corresponding to the burning flame within the combustion chamber of the engine at the second time point, calculating the time difference T.sub.o between the first and second time points, and seeking a crank angle displacement from the production of the crank angle signal to the ignition signal detected by the equation of T.sub.o /CSC.times.360, where CSC indicates a time interval between the crank angle signals and its apparatus. According to the present invention, even when the peak of the combustion light or the burning flame is detected twice for one combustion stroke, an accurate ignition timing can be detected by the detection of the first peak of the combustion light.

Abstract: An apparatus for controlling fuel injection timing, for use in a fuel injection pump of a diesel engine, comprises a toothed wheel coaxially and fixedly mounted on a drive shaft of the fuel injection pump, first and second detectors for detecting the rotational position of the tooth wheel, and a control unit, having a microcomputer, for actuating a fuel injection timing changer of the pump according to the phase difference between signals from the first and second rotational position detectors for controlling fuel injection timing. The first rotational position detector is fixedly mounted on a pump housing and the second rotational position detector is fixedly mounted on a member rotatably provided around the drive shaft of the pump. The member is generally used for converting the rotational movement of the drive shaft to the reciprocation of a plunger of the pump which supplies fuel into cylinders of the engine. The phase difference corresponds to the actual injection timing condition.

Abstract: Apparatus for maintaining the correct air/fuel mixture in internal combustion engines. In the preferred embodiment, the density of atmospheric air at concurrent temperature and barometric pressure conditions is sensed by an acoustical transducer whose electric output is electronically correlated with known volumetric flow rate data; thereby obtaining the mass flow rate of engine aspirated air. The acquired air mass flow-rate data, together with other data pertaining to concurrent engine load and condition is utilized to achieve at any throttle position a correct air/fuel ratio. In an alternate embodiment, the mass flow rate of engine aspirated air is obtained by utilizing the basic air density sensing transducer in measuring the suction pressure at the venturi throat within an engine incorporated throttle body device, while simultaneously sensing, and measuring continuously occurring changes in atmospheric conditions.

Abstract: A fuel injection apparatus for internal combustion engines in which beyond a predetermined remaining stroke during the supply stroke of the pump piston, a relief conduit is opened via a control edge. The same control edge closes the relief conduit once again during the intake stroke. During the subsequent effective intake stroke, the quantity of fuel to be injected upon the following compression stroke is metered by means of the electrically actuatable valve. The magnetic valve here is already opened before the closure of the relief conduit by the control edge, so that in the opening phase of the relief conduit, the pump work chamber of the fuel injection apparatus is flushed. In this manner, precise metering of the quantity of fuel to be injected is attained.

Abstract: The invention is directed to an arrangement for controlling the quantity of fuel to be injected into an internal combustion engine. The arrangement includes at least one electrically operated control device determining the beginning and/or the end and/or the duration of the injection of fuel into the internal combustion engine. The electrically operated control device is influenced in dependence on its own control response. The arrangement of the invention thus makes it possible to correct the error resulting from variations in the pickup and dropout times of the electrically operated control device. Embodiments are described which take into account static and dynamic variations of the control response of the electrically operated control device.

Abstract: An engine throttle valve position detector has a throttle switch formed by a rotary detector member rotatable with the engine throttle valve, a single stationary contact and a single movable contact movable by a guide groove in the rotary detector member into and out of electrical contact with the stationary contact. The stationary and movable contacts are contacted together when the throttle valve is in both fully-closed and fully-open positions, to thereby emit electric signals to an electric control unit in which the signals are processed on the basis of engine intake air flow and engine oil temperature to judge one of the throttle valve fully closed and fully-open positions.

Abstract: Disclosed is a fuel injection quantity control system incorporated with a fuel injection pump with a solenoid-operated spill valve wherein a control signal is generated for cutting off a fuel supply to engine cylinders when a rotational phase angle of a drive shaft of the fuel injection pump is coincident with a desired spill phase angle determined in accordance with engine operating conditions. The desired spill phase angle, i.e., the opening timing of the spill valve is controlled in accordance with the rotational variations of the fuel injection pump. The desired spill phase angle is divided by unit angle corresponding to a detection period of rotational angle signals produced in accordance with the rotation of the pump drive shaft, obtaining a quotient and a remainder angle. The remainder angle is converted into a time on the basis of an engine speed.

Abstract: An electric potentiometer used for conversion of a rotating movement into an electrical value. The potentiometer has a wiper passing across a resistance path and, on the other end, the wiper is rotatingly coupled with a bearing shaft. The resistance path is disposed on a mounting plate next to which is disposed on the intake pipe wall an elongated plug, made of plastic by injection molding, in which are embedded contact prongs, which are connected on the other side in an electrically conducting manner with connecting contacts extending generally perpendicular to the contact prongs.

Abstract: The amount of air entering an engine is determined by selecting the more accurate of two airflow determination means. One means measures a parameter characterizing airflow into the engine and has an adaptive correction. Another means calculates airflow into the engine as a function of engine speed and air density and has an adaptive correction.

Abstract: A method for controlling the fuel injection amount and timing for a Diesel engine by use of an electronic control unit having a CPU, a ROM, and a RAM in which the data corresponding to the steps of the method according to present invention have been preliminarily stored in the ROM, the steps Principally comprising: (i) detecting the engine speed, (ii) calculating a basic maximum fuel injection amount in accordance with the engine speed sought in the above step, (iii) detecting the intensity of the burning flame light in the combustion chamber of the engine, (iv) and correcting the basic maximum fuel injection amount calculated in the above step in accordance with the intensity of the burning flame light sought in the previous step. With this construction of the method and apparatus according to the present invention, optimum fuel injection amount and timing control can be realized in accordance with the change in altitude and/or the change in atmospheric pressure, i.e.

Abstract: A method and apparatus for controlling operating conditions of an internal combustion engine based upon sensed operating parameters of the engine expressed in the form of pulse signals, wherein the frequency of the pulses is representative of the sensed parameter. The pulse intervals of the sensed operating parameter signals are measured to the fractional level before being stored and employed by a CPU to calculate data applied to control predetermined operating conditions of the engine, such as the fuel flow rate and the ignition timing. The inventive method and apparatus attain greater operating stability for steady-state operations and excellent response under transient conditions of the engine.

Abstract: A fuel supply of an internal combustion engine is controlled by sampling a vacuum level within an intake pipe of the engine and a value corresponding to the engine rotational speed at predetermined sampling intervals, subsequently correcting a latest sampled value P.sub.BAn of the vacuum level with a latest sampled value M.sub.en of the value corresponding to the engine rotational speed to produce a corrected value P.sub.BA, and then determining fuel supply amount in accordance with the corrected value P.sub.BA. By determining the fuel supply amount in this way, hunting of the engine rotational speed especially during idling operation of the engine is prevented.

Abstract: In a fuel injection valve, a nozzle body having a valve seat, and mounted through an electrically conductive spacer on a nozzle holder, a needle valve and an insulating layer constitute an ON-OFF switch for producing signals indicating the beginning and completion of injection, and an electrical insulation member provided between the rear end surface of the needle valve and the spacer to maintain the insulated state between the needle valve and the nozzle body during the fuel injection operation.

Abstract: A fuel injection apparatus comprises a first storing device for temporarily storing cut-off fuel drained after the termination of a fuel injection, a second storing device of changeable volume for temporarily storing fuel for intake, the second storing device having a movable member which is movable in response to the quantity of fuel introduced therein, a detector for producing a detection signal showing an actural position of the movable member and a clamping device responsive to an electric signal for clamping the movable member. The clamping device is actuated to clamp the movable member in response to the detection signal when the desired amount of fuel is stored therein. The adjusted quantity of fuel stored in the second storing device is supplied to a high pressure chamber together with the cut-off fuel stored in the first storing device during the next fuel intake stroke of a fuel injection pump. As a result, extremely high accuracy control of fuel quantity can be realized.

Abstract: The invention is directed to an apparatus for metering an air-fuel mixture to an internal combustion engine with an extreme-value control arrangement for controlling to a minimal specific consumption of fuel. The extreme-value control arrangement includes a test signal generator for acting upon the fuel metered to the engine. The rotational speed and a fuel metering signal are applied by the extreme-value control arrangement as actual information with respect to the minimal specific fuel consumption. In particular, the quantities of rotational speed change and the change in duration of fuel injection are utilized to determine the minimal consumption in the case of an internal combustion engine equipped with fuel injection. Further, for a minimal consumption control, it has been shown to be advantageous to consider information as to which gear of the transmission of the engine is in place.

Abstract: A method of air-fuel ratio control for automotive internal combustion engine in which the amount of fuel to be supplied to the internal combustion engine is determined in accordance with the amount of air passing through a main air intake path, and the amount of air in a bypass is controlled in a manner to attain a predetermined air-fuel ratio for a lean mixture gas which is determined by a predetermined operating mode of the automobile. The amount of supplied fuel which changes with the amount of air in the bypass is thus corrected to perform the lean mixture gas operation in the predetermined operating mode.

Abstract: A power supply for an acoustic fuel injector (18) comprises a DC to DC converter (14) for supplying a regulated voltage to a frequency-controlled oscillator (16) which drives the injector valve or valves. The converter (14) comprises a flyback oscillator (28) including a switching transistor (32) and a transformer (34, 36) for applying rectified current pulses of variable amplitude and occurrence rate to an output capacitor (42). A variable impedance transistor (50) in the input circuit to the flyback oscillator (28) is controlled by a feedback signal (68) from the output circuit (30) to vary the cycle rate of the flyback oscillator (28) to maintain output voltage at a desired value. Start up of oscillations in flyback oscillator (28) is assisted by a resistive feedback connection (56) and oscillations are maintained by a tertiary transformer winding (38).

Abstract: An engine control system has a heater and a temperature measuring element with a temperature-resistance characteristic. The heater and element are provided in the intake pipe of an engine. Heating, which initiated by a start pulse signal generated by an engine control unit in synchronism with engine rotation is supplied to the heater through a transistor. When the heater temperature has reached a reference temperature preset in accordance with the intake air temperature measured by the element, a comparator generates an output to deenergize the heater. The period of supplying the heating power is represented by a pulse signal from a flip-flop. This pulse signal is supplied as an airflow measurement signal to the engine control unit. The engine control unit calculates the basic fuel injection quantity and determines if the starting of the pulse signal received by the control unit falls within a predetermined period from the starting of the start pulse signal.

Abstract: In order to take into consideration the different response by a hot wire sensor to changes in temperature of air as opposed to changes in temperature of fuel, the circuit configuration of a hot wire sensor for fuel flow detection differs from that for air flow detection in that an additional resistance is connected in series with the flow measuring resistance in the bridge circuit of the fuel flow detector, while the additional resistance is connected in series with the temperature compensating resistance in the bridge circuit of the air flow detector.

Abstract: An improved input circuit for an electronic vehicle speed control unit is disclosed. An ignition current sensor coil is adapted to have a voltage differential signal induced therein each time an ignition pulse is generated by the vehicle engine. Electrical noise signals generated by the vehicle engine appear as common mode signals across the ignition current sensor coil. The ignition current sensor coil is connected at each end to a capacitor, both of which are connected to ground potential. The ends of the ignition current sensor coil are further connected to the inputs of a differential amplifier. The capacitors appear in a series loop with the ignition current sensor coil for the differential voltage signals and, consequently, provide tuning for inductance. However, the capacitors appear in parallel with one another to ground potential with respect to the common mode noise signals, thereby providing high frequency noise rejection for the input circuit.

Abstract: A Karman vortex generator is disposed in the air intake passage of an internal combustion engine. The frequency of the Karman vortex generated by the generator is detected by a Karman vortex frequency detector to measure the flow rate of intake air. The frequency of the Karman vortex is in proportion to the flow rate of intake air with a Strouhal number being the constant of proportionality thereof. However, when the flow rate or the flow velocity of intake air is within a certain range, the Strouhal number fluctuates and the proportionality between the Strouhal number and the flow rate of intake air is broken. This range is shifted when the kinematic viscosity of intake air changes. The kinematic viscosity of intake air depends upon the temperature thereof.

Abstract: An electrically controllable dual fuel system for an internal combustion engine (such as, but not necessarily confined to, a diesel engine) having a liquid fuel injection system incorporating an injector pump for delivering prescribed quantities of a principal liquid fuel (e.g. diesel oil) under pressure to individual injectors for the engine cylinders comprising an electronic control unit, an electrically controllable variable flow regulator arranged to receive a combustible alternative fuel (e.g.

Abstract: A method and apparatus are provided for controlling the torque or fuel quantity limit to an internal combustion engine such as a diesel engine, at least partly as a function of the sensed level of smoke in the exhaust gas stream of the engine. An open-loop preliminary fuel quantity limit signal is provided as a function of engine speed. The actual smoke level is compared with a smoke limit value for the particular operating condition, and an error signal indicates the sense and possibly the magnitude of any difference. The error signal is the basis of a compensating signal which is added to the open-loop preliminary fuel quantity limit signal such that the resulting fuel quantity limit signal provides for maximum torque without exceeding the smoke limit. The smoke level is obtained by a direct measurement of the particulate level or the like in the exhaust gas stream. An alarm may be provided for indicating when the actual smoke level exceeds some threshold relative to the smoke limit.

Abstract: Disclosed is a method and device for regulating the preparation of fuel-and-air mixture in a carburetor, fuel injection system and the like of an internal combustion engine. The device includes an oxygen probe directly communicating with the combustion chamber of the engine. Periodically fluctuating output signal of the probe is applied to an averaging circuit which produces an average output signal over a predetermined number of engine cycles. The shape and length of the averaged output signal is indicative whether the mixture ratio is lean or rich. The averaging can be made by means of a lowpass filter, an integrator or at least one counter counting in response to the angular position of the crankshaft or the predetermined time intervals. When the probe output voltage has the form of a hump or bulge, its length or area is used for determining the actual .lambda. value in the rich range of ratios of the mixture.

Abstract: A system for diagnosing an internal combustion engine having an air-flow meter. The air-flow meter comprises a voltage divider including a variable resistor. A wiper of the variable resistor is operatively connected to a flap in an intake passage so as to produce an output voltage, responsive to the volume of the intake air, a computor is provided for computing the volume of the intake air from the output voltage and a fixed voltage at one end of the variable resistor, a smoothing capacitor is provided for charging the fixed voltage and a diagnosing circuit is provided to respond to the fixed voltage for producing a diagnosis signal when the fixed voltage exceeds a predetermined range.

Abstract: In an air-fuel ratio control method for electronically controlling the air-fuel ratio of a mixture being supplied to an internal combustion engine for a vehicle in response to operating conditions of the engine, a predetermined value of a parameter indicative of loads on the engine is set which corresponds at least to a detected value of a parameter indicative of the gear position of the transmission of the vehicle, and when a detected value of the engine load parameter is smaller than the set predetermined value, leaning of the mixture is effected. As the detected value of the above gear position parameter indicates a lower speed gear position, the above predetermined value of the above engine load parameter is set to a smaller value. Preferably, the predetermined value of the engine load parameter is set to a value also correponding to a detected value of engine temperature and/or a detected value of engine speed, in addition to a detected value of the gear position parameter.

Abstract: Apparatus for measuring fuel consumption in an internal combustion engine having controllable fuel injectors that meter fuel to corresponding cylinders at predetermined delivery rates under throttle control senses the amount of fuel being delivered to each cylinder by a potentiometer that generates a signal which is proportional to the linear displacement of a throttle rack gear. In one embodiment a transducer generates another signal proportional to the rotary speed of the engine and both signals are amplified at a fixed gain corresponding to the number of working engine cylinders to produce a product signal that is applied to an analog meter or a digital display circuit which indicate the rate of engine fuel consumption.

Abstract: A process and device for determining the composition of an alcohol-petrol mixture supplying a combustion engine. According to this process a light beam is emitted through the mixture supplying the engine, the degree to which this beam is absorbed by the mixture is determined in a wave length chosen in the wave length range corresponding to the near infra-red and adjustment of the operating parameters of the engine is controlled as a function of the degree of absorption thus measured.

Abstract: A fuel injection control apparatus for an internal combustion engine using a hot-wire type air flow sensor wherein, even during a low engine speed and in a fully opened condition of the throttle valve of the engine, the output of the air flow sensor is corrected corresponding to the opening of the throttle valve and the engine speed on the basis on a predetermined relationship therebetween, thereby providing a proper A/F ratio.

Abstract: The present invention relates to an engine control device adapted to determine a basic fuel feed rate (Tp) in response to signals from a suction air flow rate sensor (20) and an air-fuel ratio sensor (20), and thereafter a fuel feed rate (Ti). According to the present invention, suction air flow rates (Q.sub.An-1, Q.sub.An-2) are calculated first on the basis of the last and the next to last fuel feed rates (Tin-1, Tin-2). The coefficients (A, B) required to correct the properties of the suction air flow rate sensor (20) are computed on the basis of these suction air flow rates. In the present invention, a fuel feed rate is determined finally on the basis of these coefficients.

Abstract: A fuel injection apparatus is disclosed which includes two intake tubes each having a throttle valve, a fuel injection valve for injecting fuel into each of the intake tubes, a hot-wire type air flowmeter for measuring the quantity of intake air sucked into the intake tubes, and a by-pass passage which accommodates the detection portion of the hot-wire type air flowmeter. The by-pass passage has an inlet portion for introducing the static pressure of flow of the intake air sucked into each intake tube, a central portion for passing en bloc the air introduced from each intake tube and an outlet portion for discharging into each intake tube the air passing through the central portion. The detection portion of the hot-wire type air flowmeter is disposed in the central portion of the by-pass passage. Thus, the air flowmeter is able to obtain an output having reduced pulsations.

Abstract: An apparatus and method for detecting an intake air mass flow rate using a Karman vortex air flow arranged in an intake passage of an internal combustion engine, in accordance with the formula:.gamma.(x)=.gamma.(760).times.V.sub.p (x)/V.sub.p (760)where .gamma.(x) is an intake air density to be obtained; .gamma.(760) is the air density under standard atmospheric pressure, V.sub.p (x) is the amplitude value of the analog signal obtained from the Karman vortex air flow sensor; and V.sub.p (760) is the amplitude value of the analog signal under standard atmospheric pressure.

Abstract: A method is described for monitoring the air/fuel ratio in an internal combustion engine by means of the measurement of pressure variations in the induction duct of the engine and for indicating appropriate changes in the fuel supply, in a closed loop, to return the ratio to the desired value. This method is achieved by means of a device which is characterized in that it includes a pressure sensor, means for processing the signal obtained from the sensor and a microcomputer for checking whether or not the values processed by said means fall within a predetermined, previously stored range found experimentally on a test engine under proper combustion conditions. If the processed values are outside this range, the microcomputer activates an alarm signal and/or operates, directly or indirectly a device which adjusts the air/fuel ratio to return it to normal values.

Abstract: A method and a device for controlling fuel injection in multi-cylinder internal combustion engines, includes means for computing a time shift of a common time point for ignition start in respective cylinders to a new value at which pressure differentials in respective intake pipes are approximately equal and consequently .lambda.-dispersion is minimized.

Abstract: Disclosed is a method of and a device for controlling a burn-off function of a measuring resistor, particularly heated wire or heated film in an air flow sensor of an internal combustion engine. The burn-off operation for fast cleaning the measuring resistor is normally made either periodically or in response to preset operational conditions of the engine. The invention interrupts this burn-off function when detrimental operational condition of the engine depending on the rotary speed has occurred. The stoppage of the burn-off function preferably occurs after a simultaneous detection of a predetermined temperature value detected by a sensor.

Abstract: A first temperature sensor senses the temperature of intake air supplied to an internal combustion engine before the intake air is mixed with fuel supplied thereto. A second temperature sensor senses the temperature of the mixture of the intake air and fuel within the intake air passage. A control unit controls the fuel injection quantity in accordance with the difference between the sensed temperatures, thereby causing the actual air-fuel ratio to coincide with a desired air-fuel ratio. The desired air-fuel ratio is adjusted in accordance with the throttling effect of a throttle valve in the intake air passage and with engine speed.

Abstract: This apparatus measures and detects the air-flow taken into an intake pipe of an internal combustion engine, and includes an air-flow detecting sensor. The air-flow detecting sensor comprises a support frame made of heat-resistant insulation material, a heating line supported by the support frame on the upper side when viewed from the direction in which the air-flows, a heat-controlled heating current, and a resistance line also supported by the support frame on the lower side when viewed from the direction in which the air-flows which has a temperature characteristic. Air-flow detecting signals which represent the condition under which heat is transmitted to the resistance line through the air-flow are picked up from the sensor for every specified timing to set and calculate the transmitting coefficients of heat transmitted from the heating line to the resistance line, which is specified by the sensor and which is set corresponding to the amount of the signal detected by the sensor.

Abstract: A fuel injection system, especially for air-compressing, spontaneous ignition reciprocating piston internal combustion engines. At least one parameter which characterizes the injection process, such as beginning and duration of the injection, is adapted to be regulated by at least one electromagnetic control valve per cylinder unit which can be controlled by an electrically operating data processor as a function of characteristic operating parameters of the internal combustion engine. In order to compensate for transmission deviations of the electromagnetic control valves caused by wear and operation, the control pulses of the data processor are transmitted to each electromagnetic control valve via a suitable circuit in such a way that the control valve opens and/or closes with a constant time delay during each control procedure. The constant time delay of the control valve can be established as a function of the actual speed of the internal combustion engine.

Abstract: A sensor for the variable underpressure in the intake manifold of an engine produces a digital output signal which is sampled at intervals of one half of the period of pressure variation or an odd multiple of such half period, as timed in synchronism with the crankshaft revolution in a phase relation designed to intercept maximum and minimum values of pressure. The two most recent samples are stored in a shift register and their difference is formed by digital subtraction, compensated for changes of sign in successive difference operations to provide an absolute difference value output. The latter is then provided to a threshold stage which provides an output signal if the difference value does not reach a predetermined threshold. The signal of the threshold stage is integrated before it is used to produce an alarm indication or a corrective control function.

Abstract: In a fuel injection advance angle measuring apparatus, in which the advance angle is measured on the basis of an injection timing signal produced from, such as, a needle valve lift sensor and a reference timing signal indicative of the reference timing of the engine rotation, in order to remove the noise signal from the signal from the sensor, a masking signal indicating a predetermined period in which the desired component of the injection timing signal is not to be produced, is generated in response to the injection timing signal and the reference timing signal whereby to eliminate the undesired components of the injection timing signal for the measurement of the fuel injection advance angle and to obtain the fuel injection advance angle with high accuracy in measurement.

Abstract: A method of controlling an internal combustion engine in which the pressure in a cylinder or working chamber of the engine is detected by reading the output signal which is delivered from a pressure sensor when a predetermined time has elapsed from a point of time when the pressure should be detected. Based on this pressure detection, the fuel supply amount or ignition spark timing is controlled.

Abstract: A method for evaluating output signals of a sensor for measuring operational parameters of an internal combustion engine, utilizes characteristic wave forms of signal portions derived from a sensor. Threshold levels for setting the beginning and the end of an injection process are determined from threshold levels of an (n+m)th signal portion which are derived from a fraction of preceding nth signal. The device for carrying out this method includes a store for the peak value of the nth signal and a controlled discharging device which cooperates with a threshold switch and which is controlled by other parameters of the engine such as rotary speed.

Abstract: An internal combustion engine is provided with an ion current sensor in the exhaust conduit. The sensor may be simply a spark plug across which is applied the vehicle battery voltage. The operation of the engine at various values of mixture composition yields characteristic curves for the ion current and for the fluctuations in the ion current as a function of the air number. These characteristic data are used to provide set point values against which the prevailing ion current is compared. If a set point value is exceeded, the fuel-air mixture is adjusted accordingly by an integral controller.