Abstract: Methods and systems are provided for conducting an evaporative emissions test diagnostic on a vehicle fuel system and evaporative emissions control system during engine-on conditions. In one example, a first fuel vapor storage device is separated from a second fuel vapor storage device by a one-way check valve, thus preventing loading of the first fuel vapor storage device during conditions such as refueling operations, diurnal temperature fluctuations, or from running-loss vapors from a vehicle fuel tank. In this way, the evaporative emissions test diagnostic may be conducted during a cold-start event where an exhaust catalyst is below a predetermined threshold temperature required for catalytic oxidation of hydrocarbons in the engine exhaust, without increasing undesired exhaust emissions.

Abstract: Disclosed is an exhaust purification system for an internal combustion engine applied to a hybrid vehicle that performs EV travel after system power is turned on. The exhaust purification system includes: an exhaust purification catalyst; a heating element configured to generate heat with reception of power to heat the exhaust purification catalyst; a battery configured to supply the power to a motor and the heating element; a sensing unit configured to sense riding of an occupant in the hybrid vehicle; and a controller configured to execute first control to control the supply of the power from the battery to the heating element so that the power of electric energy of a prescribed ratio among activation electric energy is supplied to the heating element when the riding of the occupant is sensed by the sensing unit and a storage amount of the battery is larger than a second storage amount.

Abstract: An integrated ignition and electronic auto-choke module for an internal combustion engine and an internal combustion engine including the same. In one aspect, the module includes a housing that is configured to be mounted to an engine block of an internal combustion engine. The housing may contain at least a portion of a first temperature sensor that measures a first temperature indicative of an engine temperature. The housing may also contain a controller and at least a portion of an ignition circuit. The controller may be coupled to the first temperature sensor and configured to determine a starting position of a choke valve based on the first temperature and operate an actuator to move the choke valve into the starting position accordingly.

Abstract: A controller includes an air-fuel ratio control unit that calculates an air-fuel ratio F/B correction value and an air-fuel ratio learning value and corrects an amount of fuel supplied to each cylinder based on the air-fuel ratio F/B correction value FAF and the air-fuel ratio learning value KG. The controller further includes a dither control unit that executes dither control to adjust the amount of fuel supplied to each cylinder, corrected by the air-fuel ratio control unit, so that at least one of the cylinders is set to a rich combustion cylinder and at least a further one of the cylinders is set to a lean combustion cylinder. When the dither control is executed, the air-fuel ratio control unit prohibits execution of air-fuel ratio learning control and executes air-fuel ratio feedback control.

Abstract: Methods and systems are provided for ambient temperature estimation and engine control during sensor initialization. In one example, on vehicle start-up after a period of inactivity, during sensor initialization ambient conditions may be estimated using remotely obtained ambient conditions data. Engine actuators may be adjusted based on ambient conditions determined from remote of the vehicle during sensor initialization and on completion of sensor initialization, the engine actuator may be adjusted based on the ambient conditions determined from the sensor.

Abstract: Systems and methods for electronically controlling the fuel-to-air ratio of a fuel mixture supplied to an internal combustion engines are disclosed. In one aspect, electronic control systems and methods are provided that determine and automatically move a choke valve in accordance with a first ramp having a first characteristic that is dependent on engine temperature and ambient air temperature. In another aspect, an integrated ignition and electronic auto-choke module is provided. In yet another aspect, electronic control systems and methods are provided that dynamically control a movement characteristic of a choke valve using a feedback loop.

Abstract: A water temperature indicated at a startup timing of an engine is stored as a startup-timing water temperature. During an idling state generated after a cold start, a retard amount (S) is calculated based on the startup-timing water temperature. At this time, the retard amount (S) is set at a larger level as the startup-timing water temperature becomes higher. However, in a case that the startup-timing water temperature is higher than a predetermined temperature, the retard amount (S) is set at a smaller level as the startup-timing water temperature becomes higher. A retard amount (R) is calculated based on a current water temperature in the same manner as the retard amount (S). A smaller one is selected from the retard amount (S) and the retard amount (R), as a basic retard amount.

Abstract: Methods and systems for heating an oxygen sensor. One system includes an oxygen sensor and controller. The oxygen sensor includes a heater and an electro-chemical measurement cell and a heater. The controller is coupled to the oxygen sensor and is configured to, for each of a plurality of stages of a regeneration process, determine a predetermined temperature for heating the oxygen sensor to, determine a predetermined internal resistance value of an electro-chemical measurement cell of the oxygen sensor associated with the predetermined temperature, apply a pulse-width-modulated signal to the heater, and monitor an internal resistance of the measurement cell while applying the pulse-width-modulated signal to the heater to determine when the internal resistance of the measurement cell reaches the predetermined internal resistance.

Abstract: Embodiments for indicating fuel rail temperature sensor degradation are provided. In one embodiment, an engine method comprises delivering gaseous fuel to a cylinder based on feedback from a fuel rail temperature sensor, and during select conditions, indicating fuel rail temperature sensor degradation based on a difference between measured fuel rail temperature and an expected temperature. In this way, measured fuel rail temperature may be correlated with other engine temperatures to detect sensor degradation.

Abstract: An embodiment (control apparatus) for an internal combustion engine according to the present invention determines, based on an output value of the downstream air-fuel ratio sensor disposed downstream of a three-way catalyst, determines which air-fuel ratio request, a rich request or a lean request, is occurring. The control apparatus sets a target upstream air-fuel ratio to a target rich air-fuel ratio when the rich request is occurring, and sets the target upstream air-fuel ratio to a target lean air-fuel ratio when the lean request is occurring. Each of the target rich air-fuel ratio and the target lean air-fuel ratio is varied depending on an intake air amount. Further, the control apparatus increases a purge amount of an evaporated fuel as a magnitude (air-fuel ratio change amount ?AF, |afLean?afRich|) of a difference between the target rich air-fuel ratio and the target lean air-fuel ratio becomes larger.

Abstract: A method for controlling a hybrid powertrain system including an internal combustion engine includes controlling operation of the hybrid powertrain system in response to a preferred minimum coolant temperature trajectory for the internal combustion engine.

Abstract: A lubrication torque limit module includes a temperature module that determines a temperature of an engine and generates an engine temperature signal. A limit module generates a torque limit signal based on the temperature signal and a speed of the engine. The torque limit signal identifies an indicated torque maximum limit. A torque arbitration module limits indicated torque of the engine based on the indicated torque maximum limit. The indicated torque of the engine is equal to an unmanaged brake torque of the engine plus an overall friction torque of the engine.

Abstract: The execution operation curve is set by switching from the EGR-off time operation curve to the EGR-on time operation curve when the EGR is started with the cooling water temperature being more than or equal to the first temperature, the execution operation curve is set by switching from the EGR-on time operation curve to the EGR-off time operation curve f when the cooling water temperature becomes smaller than the second temperature that is lower than the first temperature, and controls the engine. Accordingly, frequent changes of the execution operation curve are restricted. As a result, the operation state of the engine with the EGR performed as necessary is effectively prevented from becoming unstable further.

Abstract: In a diesel engine 10 equipped with a fuel injection device 50 having a fuel supply pump 53 for pressingly sending a fuel, a common rail 52 for accumulating the fuel pressingly sent from the fuel supply pump, injectors 51 for injecting the fuel into a cylinder by an electronic control, a coolant water temperature sensor 64 for detecting an engine coolant water temperature and a fuel injection quantity map for calculating a target common rail pressure, total amount of injections, the number of multistage injection, the respective injection quantity and the respective injection quantity timing, the diesel engine 10 comprises a total injection quantity increasing means for increasing the total amount of injections in the injection quantity control arithmetic means and an injection number reduction avoidance means for avoiding that the number of multistage injections are changed by the total injection quantity increasing means when the engine is transferred to a cold state to a warming state.

Abstract: Temperature of an electric power device of a hybrid transmission is managed based upon device temperatures and power flow, ambient temperature, and a cooling circuit flow rate.

Abstract: A method for controlling fueling of an engine, the method comprising during an engine cold start and before the engine is warmed to a predetermined level, transitioning from open-loop fueling to closed-loop fueling, where during closed-loop fueling feedback from an exhaust gas oxygen sensor is utilized and where said closed-loop fueling generates a cycling of delivered fuel in maintaining exhaust air-fuel ratio at a desired level; and providing a fueling adjustment to a subsequent engine start in response to fueling information, said fueling information obtained over at least a complete cycle of closed-loop fueling following said transition from open-loop fueling.

Abstract: An engine ECU executes a program including the steps of: starting an engine by transiently increasing an amount of fuel injection when a start request is detected; prohibiting calculation of a learn value when a condition for stopping transient increase is not satisfied; stopping transient increase when the condition for stopping transient increase is satisfied; steadily increasing the amount of fuel injection in accordance with a coolant temperature TW; and permitting calculation of a learn value during steady increase in accordance with the coolant temperature TW.

Abstract: A feedback correction coeficient used to perform feedback-control of the fuel injection amount based on the air-fuel ratio of exhaust gas is calculated. A concentration updating based value is set based on the deviation of the oscillation center of the feedback correction coefficiect, and a vapor concentration correction coefficient corresponding to the fuel concentration of purge gas is updated using the concentration updating base value. During the period where the fuel concentration of purge gas is expected to sharply decrease, the concentration updating base value is increased.

Abstract: An Engine ECU executes a program including the steps of: calculating (S100) a wall deposit correction quantity fmw, a DI reference injection quantity taudb of an in-cylinder injector, and a PFI reference injection quantity taupb of an intake manifold injector; sensing (S200) an engine coolant temperature THW; if THW is higher than a THW threshold value (YES in S300) and DI ratio r is not 100% (NO in S400), making a correction (S600) with wall deposit correction quantity fmw using the intake manifold injector; if THW is at most THW threshold value (NO in S300), making a correction (S500) with wall deposit correction quantity fmw using the in-cylinder injector.

Abstract: In an internal combustion engine where an in-cylinder injector and an intake manifold injector can both be used, initial setting of a fuel injection ratio (DI ratio) in accordance with a condition of the engine is basically carried out in response to power-up of an engine ECU. Further, it is sensed that an engine start request is made after a prescribed period has elapsed since the power-up. In such a case, an initial setting value of the fuel injection ratio is updated in accordance with the condition of the engine at that time point. Thus, the fuel injection ratio between both injectors can appropriately be set in starting the engine, so that the engine is smoothly started.

Abstract: To prevent RPM decrease, misfire, and engine stall by refraining from correcting, the amount of fuel to shift an air-fuel ratio toward a lean side to the extent of exceeding a combustion limit when the internal combustion engine operates at a low load, a control apparatus is provided for controlling operation of an internal combustion engine. The apparatus includes an air-fuel ratio state determiner, a characteristic retainer and a fuel correction amount calculator, in which a coolant temperature coefficient of a coolant temperature coefficient characteristic is set to be smaller than a constant value in a region where a coolant temperature is lower than a constant temperature.

Abstract: Methods and apparatus are provided for controlling the heating of an oxygen sensor in a motor vehicle. The apparatus comprises an oxygen sensor for measuring oxygen levels in exhaust gases of a motor vehicle. The oxygen sensor comprising a heater rod, an outer electrode surrounding the heater rod, and a shell surrounding the outer electrode and configured for mounting the oxygen sensor in the motor vehicle. A first electrical connection coupled to the outer electrode and a second electrical connection coupled to the shell are configured to facilitate measurement of capacitance between the outer electrode and the shell during operation of the motor vehicle.

Abstract: The aim of the inventive method is to improve the emission values of an internal combustion engine during idling following a cold start. Said aim is achieved by inferring an adaptive value for the required fuel quantity from a characteristic curve in accordance with the temperature of the internal combustion engine and verifying during continuous lambda regulation whether predetermined adaptation conditions are met. If so, an adaptive value is determined from the parameters of the lambda regulator and the characteristic curve is adjusted according the newly determined adaptive value and the measured temperature of the internal combustion engine.

Abstract: A control apparatus for an internal combustion engine can avoid overcorrection at a lean side of air fuel ratio learning correction by unburnt fuel in a blowby gas, and prevent rotational speed reduction and engine stall during air fuel ratio open-loop control after restarting of the engine. A temperature detecting section detects the temperature of the engine based on signals of various sensors, and an air fuel ratio learning correction value changing section updates an air fuel ratio learning correction value in accordance with the engine operating condition. When the engine is stopped with its temperature having not yet reached a predetermined value after started from a cold state thereof, an amount of update of the air fuel ratio learning correction value at a lean side is set in such a manner that the lower a temperature parameter immediately before engine starting, the smaller does the amount of update become.

Abstract: A system for diagnosing operation of a cooling system for an internal combustion engine includes a coolant temperature sensor producing a temperature signal corresponding to coolant fluid temperature, means for determining either an engine load or a throttle percentage, and a control computer configured to diagnose operation of the cooling system as a function of the temperature signal, either the engine load or throttle percentage, and a fuel delivery command for controllably supplying fuel to the engine. After expiration of a diagnostic period, the control computer diagnoses the cooling system as normally operating if the diagnostic period ended by the temperature signal meeting or exceeding a predefined temperature and if a total energy used by the engine during the diagnostic period is less than an estimated energy, and diagnoses the cooling system as failing if the total energy used during the diagnostic period otherwise meets or exceeds the estimated energy.

Abstract: An engine system includes an engine having an intake manifold, a cylinder and an intake mixture motion system. The intake mixture motion system includes a plate disposed upstream of the cylinder and an actuator that moves the plate between an open position and a closed position to direct cylinder air flow. The plate is in the closed position for a predetermined period after engine start-up. A fuel system communicates with the engine and supplies a first quantity of liquid fuel to the engine at a first A/F ratio. The fuel system supplies a second quantity of vapor fuel to the engine at a second A/F ratio to provide a fuel mixture having a third A/F ratio during the predetermined period.

Abstract: An engine system includes an engine, a fuel system that communicates with the engine, and a controller that communicates with the fuel system. The controller controls a first quantity of liquid fuel to the engine at a first A/F ratio and a second quantity of vapor fuel to the engine at a second A/F ratio during a predetermined period after start-up. The liquid and vapor fuel mixture has a third A/F ratio. The controller determines an available A/F ratio of vapor fuel within the fuel tank and performs a comparison with a target A/F ratio range. The second quantity is set to zero if the A/F ratio of the vapor fuel is outside of the target A/F ratio range. The controller adjusts the first and second quantities based on a comparison between an exhaust A/F ratio and a target exhaust A/F ratio.

Abstract: A method providing solution of both of the problem of black smoke during the engine startup period and the problem of undershooting and hunting at the settling time. By adding at least an integral term QI to a basic injection quantity, feedback control of a fuel injection quantity of an engine is carried out. An initial integral term QI0, which is used during the engine startup, is predetermined. During the engine startup period, the integral term QI is set as “0” until an engine revolution number Ne reaches a predetermined startup revolution number Nes. When the Ne reaches the Nes, the initial integral term QI0 is used as the QI. The QI0 is preferably determined on the basis of one of, or both of, a water temperature and an atmospheric temperature. The Nes is preferably a value close to, or equal to, an idling revolution number Nei.

Abstract: An improved engine fuel control detects combustion instability due to the use of high driveability index (DI) fuel during cold start and warm-up and compensates the fuel control for detected combustion instability through temporary enrichment of the delivered air/fuel ratio. The usage of high DI fuel is detected during engine cranking by measuring the time required for the engine speed to increase from a lower reference speed to an upper reference speed, provided the engine run time is less than a calibrated value. A timer is started when the lower reference speed is achieved, and the timer value is compared to a crank time threshold determined as a function of the initial engine coolant temperature. If the timer value exceeds the crank time threshold before the engine speed reaches the upper reference speed, the presence of high DI fuel is indicated, and the air/fuel ratio is temporarily enriched.

Abstract: An internal combustion engine, especially of a motor vehicle, is described wherein fuel can be injected into an intake manifold or into a combustion chamber during warm up. A control apparatus is provided for determining a warm-up factor (fWL) for increasing the injected fuel quantity below an operating temperature of the engine. With the control apparatus, the warm-up factor (fWL) is determined from a base factor (fG) and a load-dependent factor (fLA).

Abstract: An improved engine fuel control detects combustion instability due to the use of high DI fuel during cold start and warm-up and compensates the fuel control for detected combustion instability through temporary enrichment of the delivered air/fuel ratio. The usage of high DI fuel is detected during engine cranking by measuring the time required for the engine speed to increase from a lower reference speed to an upper reference speed, provided the engine run time is less than a calibrated value. A timer is started when the lower reference speed is achieved, and the timer value is compared to a crank time threshold determined as a function of the initial engine coolant temperature.

Abstract: An engine fuel injection control device for performing prescribed pilot injection and main injection on the basis of the operating state of the engine. The control device includes a pilot injection correction unit for correcting a pilot injection quantity (PQ) on the basis of an ambient temperature (TA). Therefore, the pilot injection quantity (PQ) can be selected in accordance with the ambient temperature (TA). Noise and white smoke can be kept within prescribed limits when the ambient temperature is low.

Abstract: An engine combustion controller for an engine having a fuel supply system selects an engine combustion mode from one of lean combustion, in which an air fuel mixture leaner than a stoichiometric mixture is burned, and stoichiometric combustion, in which a stoichiometric mixture is burned, in accordance with an operating state of the engine and controls, via feedback, the air fuel ratio of the air fuel mixture when the stoichiometric combustion is performed using air-fuel ratio compensating value that are based on the composition of the engine exhaust gas. A preliminary tester checks the fuel supply system and determines that the fuel supply system is in a normal state when certain preliminary test conditions are satisfied, which includes checking the feedback compensating value. A prohibiter prevents lean combustion when the preliminary tester determines that the state of the fuel supply system is ambiguous.

Abstract: A sensor unit is described, in particular an air quality sensor, having a first support element, on which are arranged a first sensor element and a first heat source, assigned to the latter, and having at least one further, second support element, on which are arranged a second sensor element and a second heat source, assigned to the latter. The two support elements are configured as a common support unit and, between them, have a heat barrier for thermal isolation.

Abstract: A start-up strategy for engine feedback control that utilizes a combustion condition sensor associated with only one cylinder. On starting and warm-up, only that one cylinder is feedback-controlled at all times. Under these conditions, the amount of corrected fuel supplied to the feedback cylinder is added to a fixed incremental amount of fuel that will be supplied to the remaining cylinders. This promotes smooth warm-up without backfiring or stalling and a quicker transition to all cylinder feedback control.

Abstract: A method is provided for controlling the combustion parameters of an internal combustion engine without a PCV solenoid during a boil-off condition. The methodology records the temperature of the engine when the vehicle is turned off. When the vehicle is restarted, the methodology determines the amount the engine has cooled since it was shut down. Based on the difference in engine temperature and the current engine temperature, the methodology determines the amount of boil-off corruption remaining. The methodology then determines a new boil-off corruption fuel multiplier based on the amount of boil-off corruption remaining. The new boil-off corruption fuel multiplier is used to modify fuel control until the boil-off condition ceases.

Abstract: When feedback control of air/fuel ratio is not being performed in an engine and the engine is idling, the fuel supply amount is increased according to the engine coolant temperature. When feedback control of air/fuel ratio is not being performed and the engine is not idling, the fuel supply amount is decreased according to the engine coolant temperature. Due to this decrease correction, during the time period from when idling operation is terminated directly after starting the engine to when the feedback control of the air/fuel ratio is started, the air/fuel ratio is made lean at an early stage, and the oxygen concentration in the engine exhaust gas is increased, so that the conversion of HC by the catalyst is quickly started.

Abstract: An air-fuel ratio detecting device and a method capable of correctly and very precisely detecting the air-fuel ratio of an internal combustion engine. The air-fuel ratio detecting device comprises an air-fuel ratio sensor disposed in the exhaust system of an internal combustion engine, an air-fuel ratio sensor circuit which applies a voltage to the air-fuel ratio sensor, detects the current through the air-fuel ratio sensor and produces an output that varies in proportion to the magnitude of the current that is detected, and a storage means for storing the data of a conversion map which is used for calculating the air-fuel ratio of the internal combustion engine in response to the output of the air-fuel ratio sensor circuit.

Abstract: The present invention provides a method of controlling combustion parameters of an internal combustion engine without a PCV solenoid during a boil-off condition. The methodology detects a boil-off condition and implements one of two modes of boil-off compensation depending on the active status of an inferred alcohol content multiplier update system. The methodology also determines the nature of the air-flow through the internal combustion engine and determines the level of boil-off corruption present and the time when the corruption is complete. After the boil-off condition is determined to be complete, control of the combustion parameters are returned to a normal regime of a flexible fuel compensation system using the inferred alcohol content from the employed mode of boil-off compensation.

Abstract: The present invention provides a flexible fuel compensation system for controlling operating parameters of an internal combustion engine based on a learned value of the percent alcohol content of the fuel using an oxygen feedback system. The methodology determines a fuel composition multiplier based on the percent alcohol content and implements gasoline operating parameters for the internal combustion engine if the fuel composition multiplier is less than a first threshold value, mixed gasoline/alcohol operating parameters if the fuel composition multiplier is greater than the first threshold value, and high concentration alcohol operating parameters if the fuel composition multiplier is greater than a second threshold value for a number of comparison checks. After a predetermined period, the fuel composition multiplier is updated and re-compared to the first and second thresholds and the appropriate one of the aforementioned operating parameters is implemented.

Abstract: There is provided an air-fuel ratio control system for an internal combustion engine installed on an automotive vehicle. The control system controls the air-fuel ratio of a mixture supplied to the engine to a value leaner than a stoichiometric air-fuel ratio immediately after the start of the engine. Operating conditions of the engine and/or operating conditions of the automotive vehicle is detected. Starting of the vehicle is predicted based on the detected operating conditions of the engine and/or the detected operating conditions of the automotive vehicle. The air-fuel ratio of the mixture supplied to the engine is changed to a richer value than the leaner value when the starting of the vehicle is predicted.

Abstract: The device for detecting the air-fuel ratio in an internal combustion engine comprising an air-fuel ratio sensor arranged in an exhaust system of the engine and passes an electric current when an electric voltage is applied thereto, an air-fuel ratio sensor circuit that applies the electric voltage to the sensor, detects the current and outputs a signal proportional to the magnitude of the detected current, and a memory for storing a conversion map for calculating the air-fuel ratio in the engine corresponding to the output of the air-fuel ratio sensor circuit by the use of a reference air-fuel ratio sensor and the reference air-fuel ratio sensor circuit.

Abstract: A heater control apparatus for an air-fuel ratio sensor that is capable of supplying optimum power, regardless of the coolant temperature of an internal combustion engine at the engine start-up, is provided. When the internal combustion engine is started, a switching element 122 is continuously held at ON state, to continuously supply power to a heater 112 of the air-fuel ratio sensor 11. The duty cycle of the switching element is controlled so that the heater temperature is maintained at 1100.degree. C., after the heater resistance, which is calculated from the voltage applied to the heater and the current flowing through the heater, has reached a predetermined value, and so that a sensing element 111 is maintained at a temperature of 710.degree. C., after the air-fuel ratio sensor was activated.

Abstract: An evaporative fuel-processing system for an internal combustion engine is comprised of an evaporative emission control system including a canister, a charging passage extending between the canister and the fuel tank, a purging passage extending between the canister and the intake system of the engine, a purge control valve, and a vent shut valve. A pressure sensor detects the pressure within the evaporative emission control system. The interior of the evaporative emission control system is negatively pressurized into a predetermined negatively pressurized state, by opening the purge control valve and closing the vent shut valve. Then, the purge control valve is closed, and leakage from the evaporative emission control system is checked based on the rate of decrease in negative pressure within the evaporative emission control system over a first predetermined time period.

Abstract: A fuel metering control system for an internal combustion engine, having a feedback loop. In the system, the quantity of fuel injection (Tim) to be supplied to the engine (plant) is determined outside of the feedback loop. A first feedback correction coefficient (KSTR) is calculated using an adaptive law, while a second feedback correction coefficient (KLAF), whose control response is inferior to that of the first feedback correction coefficient, is calculated using a PID control law. The feedback correction coefficients are calculated such that the plant output (air/fuel ratio) is brought to a desired value (desired air/fuel ratio). The coefficients are calculated at least in parallel and either of them is selected to be multiplied by the quantity of fuel injection (Ti).

Abstract: A method for pulse width modulating a resistance element of an oxygen sensor. The method quickly heats the resistance element of the oxygen sensor soon after start of the engine with a relatively high duty cycle yielding wide pulse widths. During a mid oxygen sensor temperature range, the method decreasing the duty cycle and thereby the pulse width modulation. And, upon the oxygen sensor reaching peak operating temperature range, the method decreases the pulse width modulated voltage signal supplied to the oxygen sensor to relatively short duty cycled pulses.

Abstract: Provided is an apparatus for early detecting a volatility of fuel supplied to an engine after engine start, in order to more precisely provide various increasing corrections during air-fuel-ratio control. During increasing-correction (S4) after engine start, a fuel-injection amount delivered to pre-selected one of cylinders is forcibly changed in a stepped manner (S6). Measured (S10) is an elapsed time T from a time (S7) when the injection-amount is changed in a stepped manner to a time (S9) when the integral Pi of a cylinder internal-pressure reflects its variation based on the stepped change in the injection amount. Since a response to a change in an air-fuel ratio is low in case of a heavy-gravity fuel and high in case of a light-gravity fuel, a fuel volatility such as a heavy gravity or a light gravity can be measured (S11) based on a time interval of said elapsed time T.

Abstract: This fuel injection control apparatus consists of a calculating device for calculating an air-fuel ratio correction factor FAF, a learning device for learning an air-fuel ratio learning factor KG in accordance with the deviation of FAF from the reference value, and a controller for controlling the amount of injected fuel in accordance with FAF and KG. When the start enrichment FASE and the warm-up enrichment FWL are added, KG is learned in accordance with the corrected deviation which is the deviation of FAF corrected by the correction factor f(FASE+FWL) which is concerned with FASE and FWL. The learning accuracy is improved because KG is learned at each region of FWL which is divided into plural regions in accordance with the engine driving conditions.

Abstract: A lean air/fuel ratio control device is provided for feeding the engine with a mixture of a desired lean air/fuel ratio for a given time from the time on which the engine is started. A stoichiometric air/fuel ratio control device is provided for feeding the engine with a mixture of a substantially stoichiometric air/fuel ratio once the given time passes. A temperature sensor is provided for sensing the temperature of cooling water of the engine at the time when the engine is just started. A control unit is provided for varying the given time in accordance with the temperature sensed by the temperature sensor. The given time may be varied in accordance with the activity of the oxygen sensor or the temperature of exhaust gas from the engine.

Abstract: The invention is directed to a method of metering fuel to the engine during warm-up operation which precedes normal operation of the engine during which a first amount of fuel is metered to the engine. The engine is equipped with a lambda control and a device for detecting a variable suitable for distinguishing warm-up operation and normal operation of the engine. A predetermined corrective factor (FWL) is provided in dependence upon the variable. A second amount of fuel is metered to the engine during the warm-up operation which is increased by the corrective factor (FWL) so that the second amount is greater than the first amount. Lambda control is engaged during the warm-up operation and provides a desired lambda value (.lambda..sub.des). A quantity is formed indicative of the mean deviation of the actual lambda value (.lambda..sub.act) from the desired lambda value (.lambda..sub.des) when the lambda control is engaged.