Abstract: Analog circuit of a thermal type intake air flow sensor for detecting a quantity of air drawn into an automotive engine is formed as a part of the input hardware of a microcomputer for control of the engine, and the analog circuit is used for operations which need to be performed at high speed, while adjustment, an output process, etc. are executed under the same operating system as is used for engine control.

Abstract: An electrical control unit having a microprocessor and a network of counters for governing the electrical operation of a fuel control valve of a fuel injection pump. Four subtraction counters are preset by the processor; one is used as a time counter indexed by time pulses and three are used as pump angle counters indexed by pump clock pulses generated for each predetermined increment of pump rotation. Two of the pump angle counters are employed to precisely open and close the valve for regulating the fuel injection timing and quantity--the total quantity in a normal mode of operation and a pilot quantity in a pilot injection mode. In the pilot mode, the third pump angle counter regulates the main injection quantity and the time counter regulates the time delay between the pilot and main injections.

Abstract: An internal combustion engine is provided having a luminosity detector and an arrangement for measuring and controlling combustion phasing based on the location of particular gain independent parameters of the luminosity signal. The gain independent luminosity parameters are used to provide a basis for adjusting various parameters of the engine like fuel injection timing so that at least one gain independent parameter is located at a desired timing point in the combustion cycle to control combustion phasing. Alternatively, these gain independent luminosity parameters are used to determine the time in the combustion cycle at which certain combustion conditions occur. In this embodiment, the determined time of a combustion condition provides a basis for adjusting engine parameters so that the combustion condition occurs at a desired time in the combustion cycle to control combustion phasing.

Abstract: A digital fuel control system for a small internal combustion engine having a pressure sensor for detecting the instantaneous pressure in the air intake manifold of the engine to generate air pressure data. A microprocessor responsive to the air pressure data generates a fuel quantity output signal indicative of the quantity of fuel to be delivered to the engine. A fuel metering apparatus responsive to the fuel quantity output signal generated by the microprocessor meters the fuel being delivered to a fuel delivery mechanism which delivers the fuel into the air intake manifold of the engine. The microprocessor in response to the air pressure data generated by the pressure sensor determines the engine's speed and the average pressure of the air inhaled by the engine. The engine speed data and air pressure data address a look-up table to extract data indicative of the fuel requirements of the engine.

Abstract: An electronic injection system for Otto engines with injection nozzle (4) has a displaceable throttle body disposed in the intake air flow (2), and includes intake air mass measurement. In order to assure optimal measurement and dosaging of the mass flow of air at minimum structural expense and within a minimum space, particularly in the case of rapidly varying engine loads and speeds of rotation, the injection system has a convergent/divergent nozzle (12) with narrowest cross section adjustable by the nozzle body. The system includes a position indicator (18) for the throttle body, measurement devices for the pressure p.sub.O in front of the nozzle, and the pressure p.sub.L at the narrowest point of the nozzle and the air temperature T.sub.O in front of the nozzle. Also included is an electronic controller device (19) operative with at least the input variables p.sub.O, p.sub.L, T.sub.O and position (x) of the throttle body to provide an output variable opening time t.sub.O of the injection nozzle.

Abstract: A fuel delivery control apparatus for use with an engine operable on either of gasoline fuel and gasoline/alcohol fuel blend. The amount of fuel metered to the engine is controlled based upon engine operating conditions. A first correction factor is set at a value calculated based upon a signal from an alcohol concentration sensor to correct the amount of fuel metered to the engine. A second correction factor is set based upon a signal from an oxygen sensor to correct the amount of fuel metered to the engine so as to provide an air/fuel ratio feedback control. In the event of failure of the alcohol concentration sensor, the first correction factor is estimated by modifying it based upon the signal from the oxygen sensor and a difference between the calculated and estimated values of the first correction factor is calculated.

Abstract: An evaporated fuel gas purging system comprises a chamber having a case and a cap, the chamber being divided into a plurality of sub-chambers by partitioning plates each having through holes; a pair of electrodes provided in one of the sub-chambers, the one of sub-chambers being filled with an adsorbent and communicating with the other sub-chambers having an inlet port, an outlet port and a purge port, respectively; and a control circuit for detecting changes in electrical characteristics between the electrodes so that the amount of a fuel gas adsorbed by the adsorbent is detected. An evaporated fuel gas purging system further comprises a purging unit for purging the adsorbed gas, a control unit for controlling the purging unit, and a display unit operating in response to quantitative changes in the amount of the adsorbed gas.

Abstract: A method of processing a signal of a thermal flow-rate sensor, provides a temperature monitor for monitoring a temperature at a representative point on a substrate support member; obtains the temperature at the representative point corresponding to the flow rate by use of the temperature monitor; and corrects an output of the sensor in accordance with a value corresponding to the temperature as well as a value corresponding to the temperature at the representative point when the flow rate is in a steady state.

Abstract: A fuel control system for an engine has a fuel injector which injects fuel into an intake passage communicating with a combustion chamber. The quantity of a direct delivery part of fuel injected from the fuel injector which is directly fed to the combustion chamber is estimated, the quantity of a drawn part of fuel which has been on a wall surface of the intake passage and is vaporized and fed to the combustion chamber together with the direct delivery part is estimated, and the quantity of fuel to be injected from the fuel injection means is dcetermined on the basis of the estimated quantities of the direct delivery part and the drawn part so that the sum of them provides a desired quantity of fuel to be fed to the combustion chamber. The estimated quantity of at least one of the direct delivery part and the drawn part is increased as a factor which governs the degree of evaporation of the fuel on the wall surface changes in such a direction as to promote evaporation of the fuel on the wall surface.

Abstract: A fuel injection system for internal combustion engines having a fuel injection pump and a relief conduit in which a control throttle is disposed for measuring the quantity of fuel flowing out, and wherein the differential pressure effected by the throttle is measured by a differential pressure measuring unit and converted into an electrical variable, in order then to be fed to an electronic control unit by which the fuel injection system is regulated.

Abstract: A fuel control apparatus for an internal combustion engine comprises, an air intake quantity detector to detect a parameter related to an air intake quantity for the engine, a filter for filtering an output from the air intake quantity detector, a switch for changing the filter coefficient of the filter on the basis of operational conditions of the engine, a controller to control a fuel supply quantity to the engine on the basis of the output of the filter, and a corrector to correct the fuel supply quantity depending on an error between an output from the filter and another output from the same at a predetermined crank angle when the error exceeds a predetermined value, wherein the predetermined value is changed depending on the filter coefficient which is changed by the switch.

Abstract: A means and method for measuring and controlling smoke emissions from an internal combustion engine using a luminosity probe which measures the luminosity of soot in a combustion chamber of the engine. The luminosity signals generated by the probe are then used to measure smoke emissions based on an equation developed by the inventors which correlates the actual smoke being emitted from the exhaust with a predicted smoke emission value resulting from the luminosity signals. This smoke emission measurement can, in turn, be used in an engine control loop to control smoke emissions.

Abstract: A method for estimating and correcting bias errors in a vehicle system which implements iterative prediction and estimation to determine a measure of at least one determinable vehicle engine parameter determines if the vehicle engine is in a substantially steady state condition, determines a measure of error between the predicted and measured values of a control parameter while the vehicle is in the steady state condition, estimates a system bias in response to the determined error, and offsets the system bias in subsequent predictions, thereby reducing the error between the predicted and measured values of the control parameter and increasing the accuracy of the estimations of the determinable vehicle parameter.

Abstract: A fuel supply control system for an internal combustion engine having an intake pipe, and a throttle valve arranged in the intake pipe. A basic value of a fuel amount to be supplied to the engine is determined based on a load on the engine. The determined basic value of the fuel amount is corrected by a correction value for increasing the fuel amount during and/or after acceleration of the engine. The correction value is determined based on a change in the opening degree of the throttle valve. The correction valve is further determined based on a change in the magnitude of the load on the engine.

Abstract: An internal combustion engine is provided having a luminosity detector and an arrangement for measuring certain parameters and running conditions of the engine such as air/fuel ratio in response to sensed combustion conditions within the combustion chamber based on particular gain independent parameters of the luminosity signal and selected engine parameters such as speed. The gain independent luminosity parameters can also be used in an engine control loop to ajust the various parameters of the engine like air/fuel ratio so as to obtain the desired luminosity characteristics and to obtain better running of the engine.

Abstract: A system for measuring a flow rate of intake air introduced into an internal combustion engine for an automotive vehicle, includes a hot-wire type air flow meter which comprises a sensor portion having a ceramic bobbin and a heating member wound onto the ceramic bobbin, and a control circuit for controlling current passing through the heating element so as to a hold temperature of the heating element constant. The hot-wire type air flow meter monitors the flow rate of the intake air to produce a sensor signal representative of the flow rate. The system also includes a control unit which receives the sensor signal to compensate a response time lag of the sensor signal, particularly when the engine operates in a transient state, such as acceleration and deceleration.

Abstract: The invention relates to a method and arrangement for controlling the fuel metered to an engine and especially to a diesel engine. The engine includes a fuel pump drive by a shaft for which injection start and injection end is fixed by a corresponding control of the electromagnetically actuated valve. The drive pulses for pump-delivery start and pump-delivery end are generated in dependence upon the analog signal of an angle sensor.

Abstract: A fuel concentration monitoring unit includes a fuel temperature dependent error correction circuit in the unit. A fuel concentration indicative voltage signal variation rate set with taking a specific fuel concentration as reference point. The output incorporated in the unit.

Abstract: A fuel control apparatus for an internal combustion engine comprises an intake air quantity detecting means for detecting an intake air quantity for the engine, a crank angle detecting means for detecting a crank angle of the engine, a sampling means for sampling the intake air quantity every predetermined time, a first calculating manes for calculating the means value of the sampled values every predetermined crank angle, a switching means for changing the crank angle value in accordance with the revolution speed of the engine, and a second calculating means for calculating a fuel injection quantity on the basis of the calculated means value, and a fuel injection means for injecting fuel to the engine at the fuel injection quantity obtained by the calculation.

Abstract: In a method for calculating the quantity of fuel to be supplied to an internal combustion engine during a dynamic transitional mode, the quantity of fuel is calculated from a corrected intake pressure value pkorr and from the speed n. The corrected intake pressure values pkorr derive from a measured intake pressure value pm taking into consideration the ambient pressure, the ambient temperature, and the time delays between the measured intake pressure pm and the intake pressure actually present in the intake pipe during the dynamic transitional mode. The method guarantees an extremely exact metering of the fuel quantity during the dynamic transitional mode.

Abstract: In an apparatus for driving a piezoelectric element to close and open a valve member by expanding and contracting a volume of a pressure chamber, at an initial stage of a closing state of the valve member, a higher voltage than a conventional charging voltage or a lower voltage than a conventional discharging voltage is applied to the piezoelectric element, to thus create an initial large closing force at the valve member.

Abstract: A setting system (14) for setting the quantity of fuel delivered to an internal combustion engine has a first setting unit (10.1.1) and a second control unit (10.2.1). The first control unit emits, as a function of signals which are supplied to it from a first sensor arrangement (11.1), a first manipulated variable to the fuel injection pump (12.1). The second setting unit determines, as a function of signals from a second sensor arrangement (11.2), a second manipulated variable, which likewise would be directly suitable for actuating the fuel injection pump, but which is used to calibrate the first setting unit. The setting system thus set up is used whenever a sensor arrangement is used as second sensor arrangement which is slower, but measures more accurately than the first sensor arrangement. Then, the second manipulated variable corresponds more accurately to a value necessary for achieving a desired lambda value than the first manipulated variable.

Abstract: An airflow meter detects an amount of intake air flowing through an intake passage of the engine, and a fuel injector injects fuel in an amount which is determined according to the amount of intake air detected by the airflow meter. A controller calculates moving averages of outputs of the airflow meter, and the ratio of the difference between each output of the airflow meter and the moving average to a value derived from the moving average. The controller causes the fuel injector to increase the amount of fuel to be fed to the engine when the ratio is not smaller than a predetermined reference threshold value.

Abstract: A crankcase temperature sensor is provided for detecting temperature of a crankcase. A low speed basic injection pulse width is provided based on the detected crankcase temperature for low engine speed. An ordinary fuel injection pulse width is provided in accordance with engine operating conditions for ordinary engine operating condition. A comparator is provided for comparing the low speed injection pulse width and the ordinary fuel injection pulse width with each other. A larger injection pulse width is determined for injecting fuel.

Abstract: A control system for an internal combustion engine has an ignition timing control device and a combustion duration control device such as a mixture controller. Sensors detect the start and end of combustion which are compared with a look-up table of target values for the engine speed and load to provide error signals. The processed error signals provide corrections which are added to base values from look-up tables of ignition timing and mixture and supplied to the control devices so as to tend to eliminate the error signals, so that the engine runs with its designed start of combustion and combustion duration values.

Abstract: A fuel delivery system for an internal combustion engine that includes a fuel supply with a fuel pump responsive to application of electrical power for supplying fuel under pressure to fuel injectors mounted on the engine. A pressure sensor is coupled to the pump/injector fuel delivery line for measuring fuel delivery pressure. A second sensor is positioned within the fuel tank and is responsive to fuel alcohol concentration. The pump motor is energized by a pulsed d.c. signal having a duty cycle that varies as a combined function of the pressure and alcohol-concentration sensor output signals so as to maintain constant fuel pressure at the injectors while automatically compensating quantity of fuel delivered by the injectors for differing fuel alcohol concentrations.

Abstract: An apparatus for detecting the degree of opening of a throttle valve of an engine. A first value indicating the degree of opening of the throttle valve and a second value indicating the opening of the throttle valve in an idling position are detected and stored. Whether the first value is kept unchanged for a fixed interval is decided when the throttle valve is in an idling position. A stable value of the first values is provided when the first value is kept unchanged for a fixed interval and the throttle valve is in an idling position. Then the second value is updated to the stable value. A value indicating the difference between the stored first and second values is calculated. The calculated value is used to control the amount of fuel supplied to the engine.

Abstract: Disclosed is a system for controlling the fuel injection quantity at the start of a two-cycle engine, in which a predetermined amount of a fuel is preliminarily injected when a key switch of the engine is turned on, the revolution speed of the engine is smaller than a reference value and the opening degree of a throttle valve takes a predetermined change pattern.

Abstract: An engine control system comprises a circuit for selecting a first engine controlled variable or a second engine controlled variable according to engine condition, changeover value for introducing to a pressure sensor the atmospheric pressure when the circuit selects the first engine controlled variable and the negative suction pressure when the circuit selects the second engine controlled variable, an engine control circuit for controlling the engine on the basis of a selected engine controlled variable and the atmospheric pressure and a delay circuit for making the selecting circuit to select the second engine controlled variable after a predetermined time period from the time when the pressure to be introduced to the pressure sensor is changed over from the atmospheric pressure to the negative suction pressure.

Abstract: A mass airflow based control system is provided for an internal combustion engine including a throttle body and an air bypass valve. The system comprises a processor for determining a first value equal to predicted air charge inducted into the engine through the throttle valve, and includes memory for storing an initial value of a ratio of predicted current air charge inducted into the engine to predicted peak air charge capable of being inducted into the engine. The processor determines a second value equal to predicted air charge inducted into the engine through the air bypass valve based on the initial value, and determines a third value equal to predicted peak air charge capable of being inducted into the engine. The processor further determines an actual value of the ratio of predicted current air charge inducted into the engine to predicted peak air charge capable of being inducted into the engine based on the first, second and third values.

Abstract: A fuel injection system for internal combustion engines, which has a fuel injection pump and an additional device for varying the injection quantity pumped to the injection nozzle from a pump work chamber; the additional device has a blocking piston acted upon from the pump work chamber, the deflection stroke of which is controlled by an electrically controlled valve by means of which the injection duration or the injection quantity can be controlled. The operative face on the blocking piston facing the pump work chamber is smaller than the face facing the control valve and the control valve is embodied as an ON/OFF valve.

Abstract: A fuel injection control apparatus for an internal combustion engine includes a fuel injection valve, a throttle valve positioned in an inlet passage, a bypass passage communicating with the inlet passage downstream of the throttle valve, an arrangement for admitting ambient air into the bypass passage, and means for calculating a normally desired amount of fuel to be injected into the inlet passage by the fuel injection valve based on the air pressure in the bypass passage. In order to compensate for differences between the respective air pressures in the bypass passage and the downstream part of the inlet passage, means are provided for calculating an adjusted amount of fuel to be injected which is different from the normally desired amount of fuel.

Abstract: In order to accomplish aforementioned and other objects, a spark ignition timing control system, according to the present invention employs means for monitoring maximum pressure point in an engine revolution cycle, where the internal pressure in an engine cylinder becomes maximum for deriving period required for fully propagating combustion in the engine cylinder on the basis of angular difference between spark ignition initiating point and the maximum, pressure point. The means predicts concentration of one of fuels in a mixture fuel on the basis of the derived propagating period. The system compares the predicted concentration with an actually measured concentration of the relevant fuel by means of a sensor to detect failure of the sensor. When failure of the sensor is detected, fail-safe operation is performed by setting the concentration data at a predetermined fixed value.

Abstract: In an alcohol sensor failure detection system for an internal combustion engine, a failure of an alcohol sensor is detected utilizing an air/fuel ratio dependent correction coefficient during a FEEDBACK control being executed to maintain an air/fuel ratio of an air/fuel mixture at a target value with a fuel supply amount which is corrected by the correction coefficient. The correction coefficient is variable between predetermined maximum and minimum values depending on a monitored air/fuel ratio of the air/fuel mixture. When the correction coefficient is retained to the maximum or minimum value for no less than a predetermined time, the failure of the alcohol sensor is determined.

Abstract: When there is observed a tendency that the proportion of the correction by an air-fuel ratio correction value for the feedback control of an air-fuel ratio in an air-fuel mixture sucked into an engine to a target air-fuel ratio is increased in the air-fuel ratio-enriching direction in a region of a smaller sucked air flow quantity, it is judged that the leakage of air into a suction system of the engine occurs. The quantity of the correction of the sucked air flow quantity corresponding to the quantity of leaking air is set based on the relation between the air-fuel ratio correction value and the corresponding sucked air flow quantity, and the detection value of an air flow meter is corrected based on this correction quantity.

Abstract: In a multi-fuel engine which is operated on gasoline, alcohol or a mixture of the two, upon an alcohol sensor being diagnosed as being out of order, an alcohol correction factor in the injection pulse width calculation is clamped at an arbitrary value and in the case of high load operation a carburetion correction factor is incrementally increased instead of being set to a pre-recorded value for the instant load.

Abstract: An air-fuel ratio control system for an internal combustion engine is disclosed. A basic fuel injection quantity is determined by using a cylinder pressure at a predetermined crank angle, and a signal provided by an intake air temperature sensor as parameters. A compensation fuel injection quantity for an accelerating mode or a decelerating mode is determined on the basis of a predetermined cylinder pressure variation corresponding to the variation of the output of a throttle opening sensor and an engine speed. The air-fuel ratio control system does not need an expensive air flow meter.

Abstract: In controlling fuel injection and ignition timing in an internal combustion engine operating on a fuel mixture, such as gasoline and methanol, consideration must be given to the mixture ratio of the fuel mixture in determining air/fuel ratio and ignition timing, as well as in controlling the atomizing of the injected fuel. Fuel injection time is determined in accordance with air/fuel ratio, which is calculated in accordance with the expressionA/F=14.8-0.0853Pfor a fuel mixture of gasoline and methanol, where P is the mixture ratio of methanol. In addition, to enhance cold start performance, a droplet size of injected fuel below 100.mu. is desired, and this may be achieved using a heating element whose surface temperature is controlled in accordance with the mixture ratio P or by injecting compressed air with the injected fuel in an amount determined by the mixture ratio P, or both.

Abstract: A hot-wire air flow meter for detecting air flow intake has a main passage (21) and a generally parallel sub-passage (31) for bypassing said main passage, and located in the sub-passage is a hot-wire element (2a) for detecting air flow intake. A dished member (34) is located upstream from an inlet (31a) of the sub-passage, the dished member having a base portion adjacent the sub-passage inlet and an upstream projecting edge (30a) extending from said base portion. The upstream extending edge (30a) at least partially surrounds the inlet (31a) and is located between the sub-passage inlet and the main passage, the effect of the dished member tending to stabilize air flow entering the sub-passage so that the air flow is less affected by bends in pipework upstream from the air flow meter.

Abstract: A fail-detection system is designed for detecting failure of a fuel concentration sensor for monitoring concentration of one of a plurality of different types of fuels which are blended to be supplied to an internal combustion engine, which fuel concentration sensor varies output signal level depending upon the monitored fuel concentration in the blended fuels. The system comprises first means for receiving the output signal from the fuel concentration sensor for providing a monitored data associated with monitored fuel concentration, second means for providing a reference data representative of normal range of the value of the monitored data, and third means for comparing the monitored data with the reference data for detecting abnormality of the fuel concentration sensor when the monitored data is out of a predetermined relationship with the reference data.

Abstract: A method and apparatus for detecting an intake air state quantity in an internal combustion engine, where a detected value of an intake air state quantity participating in the quantity of air sucked in the engine, are dislosed. The method and apparatus are constructed so that a random number is generated, the frequency time of the above-mentioned sampling is variably set based on this random number, and the sampling frequency of the detected value of the intake air state quantity is randomly changed.

Abstract: A fuel control apparatus for an internal combustion engine which comprises a pressure detecting means for detecting a pressure in a bypass air passage which bypasses a throttle valve in an air intake system for an internal combustion engine, a first estimating means for estimating a value corresponding to the effective cross-sectional area of the bypass air passage, a second estimating means for estimating a pressure in an intake air pipe of the air intake system on the basis of a pressure value detected by the pressure detecting means and an estimated value of effective cross-sectional area obtained by the first estimating means, and an operating means for calculating a fuel injection quantity on the basis of an estimated value of pressure in the intake air pipe which is obtained by the second estimating means.

Abstract: A two-cycle engine has a scavenge pump provided in an intake passage, and a fuel injector provided for injecting fuel directly into a cylinder of the engine with compressed assist air. The quantity of intake air supplied by the scavenge pump and the quantity of the assist air are calculated in accordance with engine operating conditions. The quantity of fuel injected by the fuel injector is calculated based on the calculated quantities of the intake air and the assist air.

Abstract: Herein disclosed is a method of processing a malfunction of an accelerator pedal sensor of an automobile. An output voltage is outputted according to changes in a resistance depending upon depression of an accelerator pedal. A malfunction of the accelerator pedal sensor is shot to process and determine an acceleration value for controlling the run of the automobile in accordance with said output voltage. The acceleration value is set at a predetermined value in accordance with the malfunction of either of an idle switch for generating a signal indicating the idle position of the accelerator pedal and a wide-open switch for generating a signal indicating the wide open position of the accelerator pedal when the malfunction of the accelerator pedal sensor is judged. This judgement is conducted by detecting a plurality of times that said output voltage is outside of the predetermined voltage range.

Abstract: An engine control system for operating an internal combustion engine with any mixture of alcohol and gasoline. The control system includes an air/fuel ratio control system providing a desired fuel charge in relation to the alcohol and gasoline content of the fuel which is indicated by an optical sensor. In one embodiment, the optical sensor includes a hemispherical lens having hemispherical recesses formed through the lens base equidistant from the lens plane of symmetry. A light emitting diode positioned in one recess irradiates substantially the entire 2 .pi. steradian outer surface of the hemispherical lens. A portion of the transmitted light is reflected from substantially the entire hemispherical lens and substantially focused on a photodetector positioned in the other recess. Emitter and detector are substantially positioned at conjugate focii of the lens which provides substantially a 2 .pi. steradian collection aperture.

Abstract: A fuel injection pump for an internal combustion engine comprising a cylinder defining a pump working space, a plunger displaceable in the cylinder, and a bypass valve for bypassing fuel from the pump working space; and a method of controlling flow of fuel from the fuel injection pump to the internal combustion engine by controling the time interval between opening and closing of the bypass valve in accordance with load parameters of the internal combustion engine.

Abstract: An engine controller comprising a means for estimating an amount of the air flowing into the cylinder of the engine. The estimation means calculates the intake air amount mc(k+1) in the following equation determined from the physical model describing the law of conservation of mass for the intake air:mc(k+1)=.alpha..multidot.Q/.omega.+.beta..multidot.mc(k)where .alpha. and .beta. are constants, mc(k) is the last estimated value, Q is the flux of the detected air, and is the engine speed. The estimation is executed synchronously with the intake stroke so as to control the fuel injection amount synchronously with the intake stroke. To further improve the accuracy of the fuel injection even when the running condition of the engine changes after the estimation of the intake air amount, the fuel should be injected asynchronously with the intake stroke. We also disclose the engine controller that controls the amount of such an asynchronous injection.

Abstract: A fuel control apparatus for an internal combustion engine comprises a pressure sensor for detecting the pressure in a combination chamber and a crank angle sensor for detecting a crank angle. During compression stroke, a microcomputer calculates the difference in pressure in the combustion chamber between two crank angles, or differentiates the pressure in the combustion chamber with respect to the crank angle at an arbitrary crank angle. Then, the microcomputer normalizes the pressure difference between the two crank angles by the pressure difference between the two crank angles when the engine is in an arbitrary reference condition, for example, its start condition, or normalizes the differentiated pressure at the arbitrary crank angle by the differentiated pressure at the arbitrary crank angle when the engine is in the arbitrary reference condition, for example, its start condition.

Abstract: A fuel control is provided having a metering means for metering a weight flow of fuel, a control for controlling the metering means, a valve for determining a change in fluid pressure of the weight flow of fuel downstream of the metering means, the valve having; a pressure reaction surface disposed in the weight flow downstream of the metering means, the surface controlling an area of a window passing the weight flow of fuel therethrough, a spring attaching to the pressure reaction surface for balancing the change in fluid pressure of the weight flow of fuel against the pressure reaction surface, and a position sensor for continuously determining a position of the pressure reaction surface and continuously sending a signal of the position to the control means, wherein the control means determines the weight flow of fuel through the valve means according to the equation: ##EQU1## whereby K is a constant, F(X) is equal to an area of the window as a function of X, X is equal to a position of the reaction surface

Abstract: A combustion engine has apparatus effective to provide a fuel mixture of one or more liquid fuels such as gasoline of variable aromatic content, normal alcohols, cosolvents, octane improvers and hydrocarbons having different energy contents in an unknown combination and combine it with air in a controlled A/F ratio with an input from a fuel mixture dielectric constant sensor. The sensor comprises a capacitor in the fuel line near the engine so that the dielectric constant of the fuel mixture about to enter the engine determines the capacitance, a resistor in series with the capacitor, an oscillator providing an oscillating voltage across the resistor and capacitor at a high frequency of at least 1 MHz but less than a frequency requiring microwave components, and an electric circuit responsive to a capacitively determined electrical parameter of the capacitor such as the voltage thereacross to determine the capacitance thereof and therefore the dielectric constant of the fuel mixture.