Abstract: An intake air pressure Pm downstream of a throttle valve of an internal combustion engine is estimated by computation from a basic fuel injection quantity Tp set for an intake air flow rate Q and an engine rotational speed Ne, an intake air temperature TA, and an intake air volumetric efficiency .eta., according to the equation Pm=C.multidot.Tp.multidot.TA/.eta.. The estimated intake air pressure Pm is then used in a fuel supply control system wherein the fuel injection pressure from a fuel injection valve is such that a differential pressure relative to atmospheric pressure is constant, to thereby correct the fuel injection period of the fuel injection valve. As a result, there is no requirement for a sensor for detecting intake air pressure. Moreover, since a reference pressure chamber of the pressure regulator can be opened to the atmosphere, piping can be shortened, enabling a more compact unit.

Abstract: A fuel supply mechanism for a gas combustion engine has a tank filled with a gas fuel, a fuel injector having a fuel injection valve mounted on the gas combustion engine, a pipe for supplying the gas fuel from the tank to the fuel injector, a gas fuel cutoff valve in the pipe for cutting off the gas fuel flowing through the pipe, a gas fuel state detector for detecting a state of the gas fuel, and a control unit responsive to a detected signal from the gas fuel state detector for controlling the gas fuel cutoff valve and the fuel injection valve.

Abstract: In order to improve the accuracy in detection of a crank angle position of an internal combustion engine, the crank angle position obtained from signals from a crank angle sensor is corrected by using a cylinder pressure inside an engine cylinder sensed by a cylinder pressure sensor. While the engine is in a predetermined non-firing condition, a control unit determines a crank angular distance (A at steps S1.about.S12) from a reference crank angle position at which the crank angle sensor produces a reference angle signal (REF), to a top dead center indicative position at which the sensed cylinder pressure becomes maximum. The control unit calculates a deviation (.DELTA.REF) of the determined crank angular distance (A) from a predetermined reference angular distance (70.degree., for example), corresponding to a deviation of the mounting position of the crank angle sensor. Then, the control unit determines a corrected crank angle position (CAA) by using the thus-obtained angular deviation (.DELTA.REF).

Abstract: A gas mass flow sensor for sensing a flow of compressed natural gas into an internal combustion engine is disclosed including a main flow passage having an inlet and an outlet forming a flow passage for the flow of compressed natural gas to the internal combustion engine, a secondary flow passage positioned within the main flow passage, a compressed natural gas flow sensor positioned within the secondary flow passage for sensing the flow rate of compressed natural gas through the secondary passage and a compressed natural gas flow conditioner for conditioning the flow of compressed natural gas through at least the secondary flow passage. The compressed natural gas flow conditioner includes a plurality of screening elements positioned substantially transversed to a direction of the flow of compressed natural gas through the flow sensor and a plurality of spacers for spacing each of the adjacent screening elements from one another.

Abstract: An integrated premixture chamber is disclosed, for mixing gaseous fuel and air for delivery to a combustion chamber of an internal combustion engine. The integrated premixture chamber includes a mass air flow sensor, a throttle valve and position sensor, a fuel shut-off valve, a gas flow sensor and a fuel metering valve having discharge outlets downstream of the mass air flow sensor to provide more accurate metering. The integrated premixture chamber is controlled by an electronic unit separate from the engine's control unit.

Abstract: A method of controlling operation of a compressed natural gas vehicle as a function of a predetermined level of methane in the ambient. Vehicle ignition is turned off when a predetermined level of methane is sensed in the ambient.

Abstract: A fuel injection control system accurately determines the amount of fuel to be injected by compensating the measured crankcase pressure in view of various conditions including intake air condition, effects of exhaust gas pressure by other cylinder and others, with use of one pressure sensor. The fuel injection control system includes a pressure sensor installed in a cylinder of the engine for detecting crankcase pressure, a fuel injector for injecting fuel to the engine on the basis of the crankcase pressure detected by the pressure sensor, and a device for compensating the amount of fuel injected from the fuel injector depending on the condition of intake air in the crankcase. Another aspect of the system additionally includes controlling timing for detecting the crankcase pressure by the pressure sensor depending on the rotation rate of the engine.

Abstract: The invention relates to a fuel injection pump for internal combustion engines with a pump plunger (18), a drive shaft (11) for the actuation of the pump plunger (18) and a rotational-angle sensor (30) for detecting the angular position of the drive shaft (11), the pulse generator of which is designed as a generator wheel (32) seated firmly in terms of rotation on the drive shaft (11) and the pulse pick-up (31) of which is held on a carrier ring (35) seated rotatably on the drive shaft (11). For the purpose of narrowly toleranced exact association of the pulse generator wheel (32) and the pulse pick-up (31) both in the radial and in the axial direction, the pulse pick-up (31) is accommodated in a sensor housing (40) and this housing is fixed positively and frictionally on the carrier ring (35) by means of plug-in elements.

Abstract: An electronically controlled fuel-supply system for an internal combustion engine, comprises a fuel tank, a fuel pump mounted in the fuel tank, a fuel-injection valve delivering fuel of a fuel-supply amount, based on its valve opening time period, to an engine cylinder, a pressure regulator mounted in the fuel tank and responsive to a first pressure difference between a fuel pressure of fuel pumped and a reference pressure, for regulating the first pressure difference at a predetermined value, an internal-pressure sensor for detecting an internal pressure in the fuel tank, and a boost-pressure sensor for detecting a boost pressure acting on an open end of a nozzle of the fuel-injection valve. The pressure regulator uses the internal pressure as the reference pressure. A control unit is provided for correcting the valve opening time period in accordance with a second pressure difference between the internal pressure and the boost pressure.

Abstract: Trigger signals are obtained from fuel injection parameters to regulate the energy conversion of an internal combustion engine which has individual injection valves for each of the combustion chambers. The fuel injection parameters are detected by sensors, from which fuel flow rate as a function of time, fuel injection time and other operating characteristics are determined and used to provide trigger signals for controlling fuel injection in a subsequent operation cycle. In this way, the influence of variations resulting from manufacturing tolerance and wear of components of the injection valves can be eliminated.

Abstract: An apparatus and method for determining a characteristic of a fuel actually used in a vehicular internal combustion engine. The characteristic of the fuel actually used in the engine is determined on the basis of a fuel supply quantity (.SIGMA.Ti) to the engine during an engine start until an initial stage of an explosion of an air-fuel mixture in any one of engine cylinders and a time duration measured by a timer (Tr) from a time at which the initial explosion has occurred to a time at which a completion of the explosion has occurred.

Abstract: An internal combustion engine, in particular a Diesel engine, includes an injection pump with a filling ramp and a supply ramp of a cam ring, cam disk or cam shaft, pump pistons traveling on the filling and supply ramps, and a magnet valve controlling the injection pump and having a closure defining a supply onset. An apparatus for ascertaining at least one actual operating state of the injection pump includes a structure-borne-sound transducer ascertaining at least one actual operating state.

Abstract: Dynamic adjustment of the impact of automotive vehicle accelerator pedal position on engine inlet air valve position in which a gain is varied in accord with vehicle speed and a limit varied in accord with vehicle speed, the gain being applied in a transfer function between sensed accelerator pedal position and desired inlet air valve position, and the limit being applied to the desired inlet air valve position, with the transfer function varying in accord with an operator selection from a set of transfer functions.

Abstract: The air meter forming part of the air intake passage of the engine is equipped with an electronic circuit for measuring the rate of intake air and a memory for storing data pertaining to actual air flow rate versus output characteristics of the air meter or correction data for calculation of air flow rate. The engine control unit digitally calculates actual air flow rate to be used for determination of the amount of fuel to be supplied from a signal output from the air meter with reference to the air flow rate versus output characteristics of the air meter or air flow correction data fetched from the memory provided on the air meter body.

Abstract: A fuel supply manifold in a returnless fuel system for supplying fuel to an internal combustion engine has a fuel rail with a first end having a first opening and a second end having a second opening. A one piece end plug, which fits into the first opening to provide closure thereof, has a fuel hose connector with a fuel inlet therethrough to pass fuel to the fuel rail and a fuel temperature sensor in close proximity to the fuel inlet. The one piece end plug also has an electrical connector casing for receiving an electrical connector to conduct the fuel temperature signal to a remote location for processing. A flange on the end plug attaches to the fuel rail with a pair of bolts, and a core with O-rings thereon extends from the flange for locating and sealing the end plug to the fuel rail. The second end is capped so that fuel may not flow therethrough.

Abstract: With an electronic control device for an internal combustion engine using an oxygenated compound mixed fuel, operating conditions of the engine are detected, and are utilized to determine fundamental control data for the engine, while the dielectric constant and the refractive index of an oxygenated compound mixed fuel supplied to the engine are detected, and the oxygenated compound content of the mixed fuel is calculated according to the dielectric constant thus detected. The refractive index, and the oxygenated compound content are utilized to estimate the distillation characteristic of the petroleum refined fuel in the mixed fuel. The fundamental control data are corrected by using first correction data determined from the oxygenated compound content and second correction data determined from the distillation characteristic.

Abstract: A fuel injection pump apparatus has a cam ring angularly adjustable within a housing in which is also mounted a rotary drive shaft having an enlarged piston provided with teeth about its periphery. A transducer is provided to sense the passage of the teeth and this includes a part fixed on the housing and a second part mounted on the cam ring. The first part defines a pair of pole pieces which have opposite magnetic polarity and the second part carries a pair of magnetizable plates which remain in close proximity to the pole pieces, the plates defining projections which are in close proximity to the teeth. A sensing coil is provided in the first component and provides a signal as the reluctance between the projections varies as the teeth move past the projections.

Abstract: To detect the volatility of fuel accurately and speedily, a system for an internal combustion engine is arranged to gradually increase only the fuel supply quantity for a specified cylinder, while monitoring a variation of a combustion pressure in the specified cylinder, until the variation exceeds a predetermined level. The amount of fuel increase (such as AFR) obtained at the time the variation exceeds the predetermined level is used as a parameter representing the volatility of the fuel.

Abstract: An electronic sensor (20) for measuring methanol content in gasoline fuels for automotive engines including a sensing coil (108/108') and a paired capacitance element (42,44/42', 44') that cooperates with the coil to define an oscillating circuit wherein the gasoline methanol fuel mixture is used as a dielectric for the capacitor elements of the sensor, a change in the methanol concentration in the fuel resulting in a change in the dielectric constant of the sensor (20) which results in a change in the resonant frequency of the capacitor elements (108/108', 42/44/42', 44'), and a microprocessor circuit (160) which responds to a change in the oscillating frequency to establish a control signal that may be used by an automotive powertrain controller (24) to effect appropriate adjustments in the air/fuel ratio and ignition timing for the engine (10) to compensate for variations in the methanol content of the fuel.

Abstract: A misfire detection device for a multi-cylinder internal combustion engine detects levels of angular acceleration .beta. of the crankshaft corresponding to predetermined phase intervals of respective cylinders. Further, the differences .DELTA..beta. between the levels of angular acceleration corresponding to successively ignited cylinders are calculated as the combustion condition parameters corresponding to respective cylinders, and when the absolute variance .DELTA..beta.R of the levels of combustion condition parameter (i.e., difference of acceleration .DELTA..beta.) corresponding to cylinders whose ignition timings are separated by 360 degrees of the crank angle is continuously less than a predetermined judgment level, an occurrence of continuous misfires is detected.

Abstract: An air-fuel ratio control device for an internal combustion engine having an intake passage and an exhaust passage with a three way catalytic converter. The device comprises a fuel injector for injecting fuel and an air-fuel ratio detector for detecting an air-fuel ratio in the engine cylinder, which is arranged in the exhaust passage upstream of the three way catalytic converter. A first estimation device estimates an amount of intake air actually fed into the engine cylinder. A first decision device decides a target amount of fuel which must be fed into the engine cylinder to realize the stoichiometric air-fuel ratio, on the basis of the amount of intake air estimated by the first estimation device. A second estimation device estimates an amount of fuel actually fed into the engine cylinder, on the basis of the air-fuel ratio detected by the air-fuel ratio detector, and the amount of intake air estimated by the first estimation device.

Abstract: An altitude determining apparatus for an automotive vehicle includes a calculating part for determining a reference flow rate based on a throttle angle of a throttle valve and an engine speed of an internal combustion engine of the vehicle, the throttle angle being sensed from the throttle valve arranged in an intake passage of the engine and the engine speed being sensed from the engine, a correction part for detecting an operating condition under which additive gas is supplied to the intake passage downstream of the throttle valve and for changing the reference flow rate determined by the calculating part to a second reference flow rate according to the operating condition only when the above mentioned operating condition is detected, and a discriminating part for comparing an intake air flow rate sensed at an inlet portion of the intake passage with a reference flow rate supplied from the correction part and for determining an altitude condition of the vehicle based on the result of the comparison.

Abstract: Pedal mounted sensors are useful in vehicles for delivering an electrical signal correlative to the position of the pedal position. A pulse-width-modulated signals is preferable because it is less susceptible to signal degradation from engine noise or other factors. A pedal mount sensor capable of measuring a plurality of different angle ranges is disclosed. A stationary portion of the potentiometer includes both a mother board and a daughter board to improve manufacturability of the potentiometer. An application specific integrated circuit is substituted for direct pulse-width-modulation circuitry that permits a second, redundant circuit to be included within the potentiometer housing.

Abstract: An engine control system that relies upon throttle valve position and a throttle position detector. However, rather than measuring actual throttle valve detector output signals, a different signal is measured so that accurate positioning of the initial position of the throttle position detector is unnecessary.

Abstract: A fuel supply control system for an automotive engine determines a property of the fuel, such as the fifty percent distillation temperature T.sub.50 thereof, and the fuel injectors of the engine are controlled in accordance with the determined fuel property. When the engine is idling and the coolant water temperature WT of the engine is decreasing, the amplitude X of the feedback correction factor K.sub.2 for proportional-plus-integral control action is measured a number of times, and an average amplitude X.sub.0 thereof is calculated. The property of said fuel is determined on the basis of the thus calculated average amplitude X.sub.0 and the coolant water temperature WT using a two-dimensional map which gives the value of T.sub.50 as a function of the amplitude X of the feedback correction factor K.sub.2 and the coolant water temperature WT. The thus determined index T.sub.50 is stored in a RAM backed up by a battery. When a new fuel is supplied to the fuel tank, the value of index T.sub.

Abstract: A system for controlling the supply of fuel to a multiple cylinder, two cycle, crankcase compression, internal combustion engine wherein air flow is normally measured by a pressure sensor in the crankcase chamber of only one of the cylinders. When an abnormal condition is sensed, the supply of fuel to the cylinder associated with the pressure sensor is discontinued and in some embodiments, the control of the fuel to the other cylinders is accomplished by means other than pressure sensing.

Abstract: An electronic sensor (20) for measuring methanol content in gasoline fuels for automotive engines including a sensing coil (108/108') and a paired capacitance element (42,44/42', 44') that cooperates with the coil to define an oscillating circuit wherein the gasoline methanol fuel mixture is used as a dielectric for the capacitor elements of the sensor, a change in the methanol concentration in the fuel resulting in a change in the dielectric constant of the sensor (20) which results in a change in the resonant frequency of the capacitor elements (108/108', 42/44/42', 44'), and a microprocessor circuit (160) which responds to a change in the oscillating frequency to establish a control signal that may be used by an automotive powertrain controller (24) to effect appropriate adjustments in the air/fuel ratio and ignition timing for the engine (10) to compensate for variations in the methanol content of the fuel.

Abstract: A process for operating a combustion engine which comprises the steps of thermoelectrochemiclly regenerating waste heat rejected by the combustion engine by adding waste heat to an electrolysis cell, generating hydrogen by an amount of electricity that is reduced as a result of additions of waste heat and using the hydrogen as a stratified-charge combustant within each combustion chamber of the engine.

Abstract: A diagnostic method for an internal combustion engine determines airflow using three independent airflow determinations. The three airflow determinations are compared to each other and an error is established if one airflow determination differs significantly from at least one other airflow determination.

Abstract: A fuel vapor handling system for an internal combustion engine uses a calibrated nozzle in a device which determines the mass flow of fuel vapor being drawn into the engine, while controlling the vapor flow in response to commands from a fuel controller, so as to permit finer control of the air/fuel ratio.

Abstract: An evaporative fuel-purging control system for an internal combustion engine includes a mass flowmeter arranged across a purging passage of the engine for measuring a flow rate of a mixture of evaporative fuel and air being purged. A desired flow rate of the mixture is set according to operating conditions of the engine. The desired flow rate of the mixture is compared with a measured flow rate of the mixture obtained by the mass flowmeter, and the opening of a purge control valve arranged across the purging passage is controlled based on results of the comparison.

Abstract: The present invention discloses a method for identifying the concentration of fuels or gases in air, particularly in the intake of motor vehicle motors, with ultrasound measurement, comprising the steps of conducting an air/vapor mixture whose concentration is to be identified through an ultrasound measuring section of known length, directing ultrasound through the mixture in the measuring section, determining the speed of sound through the air/vapor mixture; and identifying the concentration of the mixture on the basis of the speed of sound through the mixture in the measuring section.

Abstract: An electronic fuel injector control is provided for selectively activating fuel injectors for introducing macroscopic liquid fuel droplets into the vacuum chamber of a device for converting fuel into microscopic fuel droplets and fuel vapor. The control has a rotatably mounted rotor shaft, connectable to the rotor in the vacuum chamber and fuel conversion signal device to provide first periodic signal pulses responsive to the angular rotational position of the rotor shaft. Engine sensor electronics is responsive to input signals from engine sensors indicative of engine condition and is further responsive to an output signal pulse from the fuel conversion signal device each time the vane sweeps past the fuel injector. A sensor is provided which is responsive to the desired angular position of the engine crankshaft to provide second periodic signal pulses.

Abstract: In a fuel blending ratio detecting method, a first blending ratio of the methanol in the fuel supplied to an internal combustion engine is detected by a blending ratio sensor; an air/fuel ratio feedback compensation coefficient computed on the basis of an output of an O.sub.2 sensor is used to compute a feedback learned value, and the current blending ratio compensation coefficient is multiplied by this value to compute the next blending ratio compensation coefficient so as to obtain a second blending ratio; the current blending ratio compensation coefficient is multiplied by a peak mean value of the computed feedback compensation coefficient to compute the next blending ratio compensation coefficient so as to obtain a third blending ratio; and the first, second or third blending ratio is selected according to the operating conditions of the internal combustion engine.

Abstract: When or just after an engine (1) is started, a starting switch (9) is turned on and a value is set in a just-after-starting counter in a CPU (114). The starting or just-after-starting state is detected. Fuel temperature and fuel properties are detected by a fuel properties sensor (16). The detected values are calculated in the CPU (114). Fuel temperature detection output is corrected, then a filter value or average value is calculated and stored in RAM (114b) in the CPU (114) and just after the engine is started, based on the stored value, driving of a bypass control valve (6) and an injector (12) is controlled and the fuel amount or air amount is controlled for the engine. Thereby, it is enable optimum fuel amount control when and just after an engine is started regardless of the differences in the fuel properties.

Abstract: A method for accurately determining the measure of mass airflow into an internal combustion engine is implemented with a controller that determines measures of various engine parameters, determines a prediction set including at least one predicted value of a measurable engine parameter and at least one predicted value of mass airflow into the engine, determines an estimation set including at least one estimated value of mass airflow into the engine and controls the engine in response to the estimated value of mass airflow.

Abstract: A method for accurately determining the measure of mass airflow into an internal combustion engine determines measures of various engine parameters and implements the mathematical modeling technique of prediction and estimation.

Abstract: A method includes a step of calculating an estimated blending ratio of a mixed fuel supplied to a combustion chamber of an internal combustion engine and a following equation is effected in this step to derive the estimated blending ratio:B(t)=k*B(t-1)+(1-k)*Bs(t-n)where t is an integer,n is a first delay coefficient set according to an operation parameter and a type of the engine,B(t-1) is an estimated blending ratio derived in the preceding cycle,Bs(t-n) is a blending ratio obtained by use of said blending ratio sensor in a cycle which was effected n cycles before the current cycle, andk is a second delay coefficient set according to a operation parameter and the type of the engine.

Abstract: A knocking device for an internal combustion engine which detects the ionization current through an ignition coil just prior to the time of ignition, and judges whether or not the ionization current is above a predetermined level after a predetermined time or crank angle from the ignition. If the ionization current is above the predetermined level, it is judged that knocking has taken place. Accordingly, knocking can be detected simply and surely.

Abstract: In a fuel blending ratio detecting method, a first blending ratio of the methanol in the fuel supplied to an internal combustion engine is detected by a blending ratio sensor; an air/fuel ratio feedback compensation coefficient computed on the basis of an output of an O.sub.2 sensor is used to compute a feedback learned value, and the current blending ratio compensation coefficient is multiplied by this value to compute the next blending ratio compensation coefficient so as to obtain a second blending ratio; the current blending ratio compensation coefficient is multiplied by a peak mean value of the computed feedback compensation coefficient to compute the next blending ratio compensation coefficient so as to obtain a third blending ratio; and the first, second or third blending ratio is selected according to the operating conditions of the internal combustion engine.

Abstract: The invention relates to a process and a device for determining operating characteristics of a cylinder (1) in a combustion engine in which each cylinder is provided with an intake duct (4) for the air/fuel mixture which is equipped with a member (5) for controlling the flow rate of the said mixture and which opens into the cylinder via an inlet port (6), a pressure sensor (11) being connected to the said intake duct between the control member and the port (6); the pressure sensor (11), which is independent of the components to be monitored, is used to detect in continuous fashion the pressure in the intake duct (4) between the control member (5) and the port (6); this pressure is converted in continuous fashion into an analog electrical signal representative of the pressure and of its variations; and this electrical signal is processed (in 12) in such a way as to obtain at least one desired operating characteristic of the cylinder.

Abstract: A motor vehicle fuel composition sensor is responsive to a dielectric constant of a mixture of two fuels such as gasoline and methanol to indicate the relative concentrations of each. The sensor is fuel temperature dependent at high concentrations of methanol; and a fuel temperature sensor thus provides a fuel temperature signal for fuel composition signal correction. Diagnostic apparatus stores references defining permissible operating ranges for the fuel temperature and fuel composition sensor outputs and compares the sensor outputs with these ranges to detect abnormal sensor operation. The reference defining the end of the fuel composition sensor range at maximum methanol, however, is corrected for fuel temperature if the fuel temperature sensor output is within range. An out of range signal from either sensor causes a default value to be substituted for fuel composition.

Abstract: An electronic sensor (20) for measuring methanol content in gasoline fuels for automotive engines including a sensing coil (108/108') and a paired capacitance element (42,44/42',44') that cooperates with the coil to define an oscillating circuit wherein the gasoline methanol fuel mixture is used as a dielectric for the capacitor elements of the sensor, a change in the methanol concentration in the fuel resulting in a change in the dielectric constant of the sensor (20) which results in a change in the resonant frequency of the capacitor elements (108/108',42,44/42',44'), and a microprocessor circuit (160) which responds to a change in the oscillating frequency to establish a control signal that may be used by an automotive powertrain controller (24) to effect appropriate adjustments in the air/fuel ratio and ignition timing for the engine (10) to compensate for variations in the methanol content of the fuel.

Abstract: An internal combustion engine control device having an exhaust gas recycle system which has an exhaust gas recycle line to an air intake pipe, the engine control device comprises at least pressure detect means as one of driving condition detect means for detecting a pressure for calculating an exhaust gas flow rate while said exhaust gas is recycled. A trouble detect means is provided for detecting a trouble in the exhaust gas recycle system on the basis of the pressure value detected by the pressure detect means. An engine control means is provided for controlling the engine speed based on the detected driving conditions by the driving condition detect means and based on an atmospheric pressure calculated from the pressure value detected by the pressure detect member.

Abstract: A fuel vapor handling system for an internal combustion engine uses a calibrated nozzle in a device which determines the mass flow of fuel vapor being drawn into the engine, so as to permit finer control of the air/fuel ratio.

Abstract: Engine performance is optimized by storing a plurality of engine strategy maps (A, B, etc.), each such map containing desired engine performance characteristics, and selecting one such map by using fuzzy logic techniques to evaluate selected engine sensor output signals. Preferably, a new engine strategy map is not selected unless (1) additional fuel has been added to the vehicle's fuel tank; and (2) selected sensor output signals have experienced at least a minimum deviation from their nominal values, thus indicating that a different blend of fuel is being supplied to the engine.

Abstract: An altitude decision system and engine operating parameter control system using the same for accurately detecting and correcting for altitude uses three signals, viz, the signal from an engine revolution number sensor, the signal from a throttle sensor for detecting the angle of opening of a throttle valve, and a fundamental fuel injection pulse width signal which is computed by engine operational parameter-computer from inputted signals from a mass air flow sensor and the revolution number detection sensor. Having accurately derived the altitude, the fuel injection pulse rate, the intake air flow and the ignition timing are corrected.

Abstract: This invention relates to apparatus for determining the energy content of a fuel and delivering an engine controlling signal responsive to the determined energy content.

Abstract: A line (3) provided between the head space (11) of the fuel tank (10) and the induction tube (1) of the engine contains an absorption element (9) and can be shut off by a signal-actuated servo valve (8) connected to the outlet from the absorption element. The line (3) is provided with a first sensor (4) preceding the absorption element (9) and detecting gas flows. A vacuum actuator (12) following the servo valve (8) is provided with a second sensor (13) which gives a signal when actuated. The first sensor (4) and the second sensor (13) are connected for carrying signals to a diagnosis block (14) which compares them with the signal (17) actuating the servo valve (8) and uses them for fault diagnosis.

Abstract: A compact hot-wire type air flow meter for an internal combustion engine with a high measuring accuracy is provided with a primary flow path forming an intake air passage and an auxiliary flow path incorporating therein a hot-wire element for measuring the intake air. The auxiliary flow path is defined by a flow path in an axial direction of the primary flow path and a flow path in a radial direction of the primary flow path.