Abstract: In the control method and apparatus of a direct injection gasoline engine, as for the uniform charge combustion mode performing only the intake stroke injection and the stratified charge combustion mode performing only the compression stroke injection, the injection timing is determined by referring to the injection timing map set for each mode. On the other hand, in the double injection mode performing the intake stroke injection and the compression stroke injection, the injection timing map for the intake stroke injection and the injection timing map for the compression stroke injection are both equipped, and the injection timing in the intake stroke injection is determined by the fuel quantity being injected by the intake stroke, and the injection timing in the compression stroke injection is determined by the fuel quantity being injected by the compression stroke.

Abstract: An internal combustion engine that burns fuel from a fuel source, and an engine including a block assembly with a piston cylinder, a combustion chamber connected to the piston cylinder, and an air/fuel mixing area that communicates with the combustion chamber for delivering an air/fuel mixture to the combustion chamber. A fuel delivery system is connected to the block assembly, and the fuel delivery system is adapted to deliver a selected amount of fuel into the mixing area for mixing with air therein to provide an air/fuel mixture having an air-to-fuel ratio in the range of approximately 20:1 to 45:1, inclusive. A spark plug is connected to the block assembly and positioned to generate a spark in the combustion chamber to detonate the air/fuel mixture. The spark plug has a center electrode and a ground electrode axially spaced apart from each other by a spark gap in the range of approximately 1.8 mm to 3.0 mm.

Abstract: An electronic engine control system for a lean burn engine includes a unit for detecting an amount Qa of intake air fed into a cylinder of the engine, a unit for detecting an engine speed Ne, a unit for calculating a basic fuel injection pulse width TPbas on the basis of the intake air amount Qa and the engine speed Ne, and a unit for determining control parameters containing any of at least an air-fuel ratio, an ignition timing, a fuel injection timing, a throttle opening and an EGR rate in accordance with an operating state of the engine in optimum. A reference TPref having the same dimension as the basic fuel injection pulse width TPbas and which is a function of an accelerator operating amount determined on the basis of the accelerator operating amount is determined as a load parameter used upon determination of the control parameters of the engine in operation with a lean air-fuel ratio.

Abstract: Exact metering of the fuel to be injected into the cylinder of an internal combustion engine takes into account the pressure in a high-pressure common rail, the required injection mass of fuel, and a compression prevailing in the respective cylinder at an injection onset.

Abstract: A method is provided for enriching a fuel to air ratio in an engine during acceleration based on a known fuel multiplier. Initially, the method retrieves the fuel multiplier from a dynamic crankshaft fuel control (DCFC) system. This system uses the fuel multiplier to reduce the amount of fuel delivered to the engine. When acceleration is desired, the method increases the overall acceleration enrichment values as a function of the DCFC fuel multiplier. Thus, when the vehicle is launched via a throttle tip-in while the DCFC system is active, the acceleration enrichment values are increased thereby improving drivability by having combustion taking place in a richer environment.

Abstract: A method of calibrating an injector driver system including an injector driver circuit, a logic device connected to an input line of the injector driver circuit, and an information storage device associated with the logic device, involves testing the injector driver circuit once assembled. A predetermined test is connected to the injector driver circuit. A pulse width modulated signal having a predetermined duty cycle is applied to the input line of the injector driver circuit and the corresponding current level through the test load is measured. A value indicative of the measured current level is stored in the information storage device for later retrieval during operation of the injector driver system.

Abstract: A method for transitioning between a first engine operating mode and a second engine operating mode of an internal combustion engine involves establishing an engine mode transition region between the first engine operating mode and the second engine operating mode, which engine mode transition region is defined by at least one engine operating parameter. The engine operating parameter which defines the engine mode transition region is monitored. When the engine is operating in the transition region a first engine operating mode fuel rate is determined, a second engine operating mode fuel rate is determined, and an engine mode transition region fuel rate is determined which is a function of both the first engine operating mode fuel rate and the second engine operating mode fuel rate.

Abstract: A fuel supply control system for an internal combustion engine has an exhaust gas-purifying device arranged in the exhaust system of the engine. When a predetermined high load condition of the engine is detected, an amount of fuel supplied to the engine is increased. Temperature values indicative of the temperature of the exhaust gas-purifying device are stored and a stored temperature value is read out according to operating conditions of the engine. A correction coefficient for correcting the read-out temperature value is determined, and the temperature of the exhaust gas-purifying device is estimated based on the read-out temperature value and the determined correction coefficient. When the predetermined high load condition is detected and at the same time the estimated temperature is higher than a predetermined temperature value, the amount of fuel supplied to the engine is actually increased.

Abstract: The present invention provides a method for determining ethanol thresholds for a flexible fuel control system for a motor vehicle capable of operating on more than one type of fuel. Preferably, the ethanol threshold is determined from an off-idle purge-free cell from a matrix of fuel adaptive memory cells normally used to compensate for car-to-car variations in required fueling. The ethanol threshold is periodically reduced to compensate for levels of alcohol creep indicated by the amount of purge-free adaptive memory elevation. If the learned value of percent alcohol content of the fuel is less than the ethanol threshold, gasoline operating parameters are implemented for the internal combustion engine. The off-idle purge-free cell also provides a basis for interpolating an on-board diagnostic (OBDII) ethanol threshold. As such, the OBDII monitors are only enabled if the learned value of percent alcohol content of the fuel is less than the OBDII ethanol threshold.

Abstract: In an outboard motor having a fuel-injected two-cycle engine, engine speed, throttle setting, engine temperature and/or other variables are detected and a basic fuel injection volume determined. Fuel is supplied to each of the engine's cylinders according to the detected values. When the engine is operating at a high speed, trim angle and vessel speed are detected. The trim angle and vessel speed are used to correct the basic fuel injection volume determined before high speed operation of the engine is detected.

Abstract: A control system for a fuel injector system for an internal combustion engine is provided with a method by which the magnitude of the start of air point for the injector system is modified according to the barometric pressure measured in a region surrounding the engine. This offset, or modification, of the start of air point adjusts the timing of the fuel injector system to suit different altitudes at which the engine may be operating.

Abstract: An ECU is equipped with multiple microprocessors. Each microprocessor has an erasable ROM. A communication port of a first microprocessor is connected via an external communication line to a memory overwriter while another communication port of the same microprocessor and a communication port of a second microprocessor are connected to each other via an internal communication line. Before overwriting the contents of the ROM, each microprocessor stores its own identification number whose value is obtained by incrementing the identification number received from the memory overwriter and sending the incremented identification number to the next stage microprocessor. In this way, there is no need to store the identification numbers beforehand in nonerasable memory regions inside the microprocessors.

Abstract: A programmable interface which connects to an engine control device and allows convenient entry of engine performance limitation data such as maximum allowable vehicle speed and engine RPM's. Such entered data is stored and processed so as to interface with existing and/or modified engine controllers to produce the desired vehicle performance limitations. Programmable data entry devices include an alphanumeric keypad, a wireless remote keypad, a keychain unit, and an encoded ignition key. Wireless transfer of data can be achieved through RF or light transmitters/receivers, or active and passive transponders/interrogators. Once processed, the data can be used, for instance, to alter or generate pulse trains which control ignition spark, fuel injection, or carburetion.

Abstract: A method for controlling a direct injection internal combustion engine by measuring both the degree of actuation of an accelerator pedal and the engine speed to provide optimal engine tuning parameters. According to the method, a table showing the pressure/air temperature ratio in the intake manifold is established, during engine tune-up, for each degree of actuation/speed pair. The pressure and temperature of the intake air are measured during normal operation, and the measured pressure/temperature ratio is formed. The opening angle of a throttle in the intake manifold is adjusted to make the ratio dependent on a set value read out of the table. Reverse reading of the table is performed to determine a virtual degree of accelerator pedal actuation on the basis of the measured speed and ratio, thereby providing at least one of the optimal engine tuning parameters.

Abstract: A direct injected gas engine system is made more suitable for use with a fuel of natural gas by a fuel control system providing variable gas pressure control to reduce gas pressure compared to that applied at full load, and extend fuel pulse duration for light loads as compared to fuel pulse duration at light loads if applied at the full load gas pressure. The light load fuel pulse duration can now be extended to be at least as long as the ignition delay period of the engine. A variable gas pressure regulator under the control of the engine's electronic control module provides the desired gas pressure control. Engine speed and load parameters are used to monitor engine conditions and provide signals to the electronic control module, which may use them to set the appropriate pressure in a map mode. The apparatus and method of operation improves efficiency and lowers emissions at light loads.

Abstract: A method and apparatus are disclosed for controlling operation of a spark-ignited internal combustion engine by adjusting pulse width of fuel injected into the engine. An initial fuel pulse width is set for respective pairs of engine operating parameters such as engine speed and manifold pressure. The pulse width is adjusted by a control, for each pair of parameters, to obtain maximum performance, for example, as indicated by a torque detector. Each time a pulse width is adjusted, all previously adjusted pulse widths are compared with corresponding pulse widths in stored template fuel maps. The best matched template fuel map is then used in conjunction with all previously adjusted points to create a new operational fuel map to run the engine until a more updated operational fuel map can be created upon additional fuel pulse widths being tuned.

Abstract: A method and system for generating a fuel pulse output signal to control fuel delivery from a fuel injector to a cylinder of an internal combustion engine. A plurality of holding registers asynchronously receive a plurality of fuel pulse data from a processor. The plurality of holding registers are memory-mapped and store the plurality of fuel pulse data until subsequent fuel pulse data is received from the processor. A plurality of match registers are coupled to the plurality of holding registers for comparing the fuel pulse data with a reference signal and generating a fuel pulse output signal based on the comparison between the fuel pulse data and the reference signal.

Abstract: A control apparatus of an internal combustion engine has: an air flow amount determining unit for determining a request intake air flow amount corresponding to a target output of an engine; a fuel flow amount determining unit for determining a request fuel flow amount to be supplied to the engine; an intake air amount limiting unit for outputting a predetermined limit value as an intake gas total amount value when the determined request intake air flow amount exceeds the predetermined limit value under a predetermined control condition; and a correcting unit for correcting the value of the request fuel flow amount so that the engine generates the target output on the basis of the request intake air flow amount and the limit intake air flow amount when the intake air amount of the engine is limited.

Abstract: A method of operating a computer to automatically produce production control software for a natural gas engine controller (104) on a machine is provided. The controller (104) is adapted to control a natural gas engine (106). The method includes the steps of (1) as a function of user input, defining a set of controller (104); and (2) producing control software to operate the controller (104) as defined by the specifications.

Abstract: An engine speed control system for an engine of the type having a throttle position sensor for outputting throttle position data, from which engine control parameters are determined, is disclosed. In accordance with this system, an output value of the throttle position sensor is obtained. If the output value is within a predetermined range, an adjustment value is calculated. If the adjustment value is within a predetermined range, a new throttle position value is calculated based on the output value of the throttle position sensor as adjusted by the adjustment value. Engine control parameters, such as timing and fuel injection volume, are then determined based on the adjusted throttle position value.

Abstract: A method for controlling processes in a motor vehicle is intended, for example, for open-loop/closed-loop control of combustion processes, transmission switching processes or braking processes. An engine characteristics map is formed by operating quantities of the respective process and is represented by a number of support points. In the corresponding control unit, for each support point a piece of information about the value of the map at the position of the support point is provided. In the open-loop/closed-loop control of the process, for a determined working point of the process at least one map value that is decisive for this working point is determined from the map and taking account of this, at least one control quantity for the emission of a control signal is formed. The map is automatically adapted to a changed process behavior. For the adaptation, a correction value is determined for a certain operating phase of the map.

Abstract: Method and device for regulating the NO.sub.x emission of an internal combustion engine. It has been found that the NO.sub.x emission is dependent on the efficiency of the engine. That is to say the NO.sub.x emission can be optimized by determining and controlling the efficiency. This can be performed by making the measured and determined efficiencies equal to one another by altering the air/fuel ratio.

Abstract: An engine power train control method and control apparatus for a vehicle having an engine and an automatic transmission is capable of quickly changing an air-fuel ratio to meet the requirements for exhaust gas without producing shocks and without reducing engine torque. An air-fuel ratio command value is varied stepwise for transition between an air-fuel ratio for lean-burn operation and a stoichiometric air-fuel ratio, and at the same time, the period following the completion of the stepwise variation of the air-fuel ratio command value, a basic fuel amount fed to the engine is varied stepwise from a value determined according to the air amount and an engine speed to a value determined according to a position of an accelerator pedal of the vehicle and the engine speed. In this way, shocks do not occur and the operability is improved, because the engine torque remains substantially constant through the air-fuel ratio transition.

Abstract: A control device and a control method capable of eliminating a torque variation in changing an air/fuel ratio and establishing a compatibility of promotion in fuel economy with promotion in drivability is provided. The device includes an outer environment detector for detecting an outer environment in running a vehicle, a running environment determining device for predicting a current running environment in accordance with the outer environment, a data storage device for storing data for changing a driving characteristic, a selecting device for selecting the data, a control quantity calculator for calculating a control quantity based on the data, and a control actuator for controlling a control object.

Abstract: Described herein is a drive-by-wire vehicle engine output control system. The system permits good-response acceleration by a driver's simple and reasonable operation, i.e., by operating an accelerator pedal and also a prompt response even when a sudden load change occurs. Further, the system permits precise speed control by simple equipment even when the deviation of a vehicle speed from a target vehicle speed is large. Output changes of an engine can be controlled within a permissible output change range by (a) comparing a target autocruise engine output with an acceleration demanding ending output, choosing the larger engine output and then controlling the engine to give the larger engine output, (b) controlling the engine to achieve a target autocruise engine output obtained from a speed correction torque and a running load torque or (c) limiting an engine control quantity on the basis of a permissible output change value.

Abstract: An adaptive closed loop fuel control system generates an index of maturity value which indicates the extent to which parameters which characterize an individual engine have been learned and stored for future use in a non-volatile memory. A timer produces the index of maturity value by measuring the elapsed time during which the fuel control system has successfully operated the engine at or near stoichiometry within a predetermined range of engine speed and load conditions. A backup mechanism counts the number of HEGO sensor state changes as the closed loop controller operates in an adaptive mode, setting the index of maturity to a predetermined value even when the measured adaptation time fails to indicate an adequate amount of adaptive operation.

Abstract: A method and a device for monitoring the functions of a sensor, in particular of a sensor for detecting a measurable value in a motor vehicle. If specified operating states exist, a measurable value is detected and compared to a reference value. Faults are detected when a measured value, held by the sensor, deviates by more than a tolerance value from a reference value. A measured value which had been detected and stored at an earlier instant when a corresponding operating state existed is used as the reference value.

Abstract: A method for retaining and recalling technical data associated with a solenoid-operated fuel injector improves engine emissions. Each fuel injector is tested to generate technical data specifications relating to the fuel injector. The technical data specifications are then transferred to a memory means, such as an EEPROM memory chip, which is attached to the fuel injector. The injector then carries its unique technical data specifications. The technical data specifications can then be read from the fuel injector and the recalled technical data specifications are provided to a vehicle computer. The vehicle computer adjusts for variations between fuel injectors to collapse variability of injectors to a single, centered injector flow.

Abstract: A fuel injection control system suitable for use with internal combustion vehicle engines fueled by compressed natural gas or the like. A conventional liquid-fuel closed-loop injection timing controller establishes the desired fuel delivery rate which is then translated into value which controls the duration of each injection command signal. The rate-to-duration translation is performed by accessing stored values which specify the current operating characteristics of the injectors as determined by sensed fuel pressure, fuel temperature and injector actuation voltage values.

Abstract: A method of controlling the mass of air and fuel delivered to an internal combustion engine per cylinder, per cycle, by utilizing a unique control algorithm.

Abstract: Conventional control modules, such as vehicle control modules, VCM, powertrain control modules, PCM, or engine control modules, ECM, provided with diagnostic and/or emulation ports, or simply with portions of the wiring harnesses which are devoted to diagnostic or emulation functions, are retrofitted with an adapter module which allows the originally manufactured control module to be reconfigured to operate in a dramatically different protocol without any system redesign. The memory within the originally manufactured control module can be disabled, bypassed or rewritten to store a new program contained in one of a plurality of programs in an adapter memory or contained in one of a plurality of memories in the adapter module. One application includes retrofitting conventionally manufactured gasoline or diesel vehicles to run on alternative fuel, such as propane, compressed natural gas or liquefied natural gas and the like.

Abstract: A device and a method for controlling an internal combustion engine, in particular a diesel internal combustion engine, having at least one solenoid valve, are described. On the basis of a desired quantity of fuel, an actuation period is determined for the solenoid valve and a signal for fixing the end of actuation is prescribed on the basis of the actuation period. Depending on the operating state of the internal combustion engine, the actuation period is determined either by means of a pump characteristic table or the desired quantity of fuel is used directly as the actuation period. Moreover, depending on the operating state of the internal combustion engine, either an uncorrected or a corrected signal is used for fixing the end of actuation.

Abstract: A method of storing a correction value of a control variable in an engine control device includes the steps of transferring a correction value stored in a RAM to an E.sup.2 PROM by serial communication immediately after a power supply switch is turned off. The correction value stored in the E.sup.2 PROM is then transferred back to the RAM immediately after the power supply circuit is turned on. In this way, when the engine control device is not in operation, the correction value is retained in the E.sup.2 PROM.

Abstract: A fuel injection control system suitable for use with internal combustion vehicle engines fueled by compressed natural gas or the like. A conventional liquid-fuel closed-loop injection timing controller establishes the duration of each injection command signal by the combination of a P.I.D. controller responsive to the level of exhaust oxygen, an adaptive table which stores previously determined fuel delivery rate values for particular engine speed and load conditions, an injector supply voltage table which stores fuel delivery rate correction values which compensate for variations in injector operating potentials, and a two-dimensional correction table which provides correction values to compensate for variations due to fuel pressure and resistance variations in the injector actuators due to temperature variations.

Abstract: The ability of an automotive computer for controlling an engine is enhanced by allowing the automotive computer to be controlled by an arbitrarily selected one of a plurality of engine control programs according to arbitrary driver discretion. The bus connecting the computer and memory of a conventional automotive computer is connected to a computer controlled operator interactive control module and an expanded memory. The operator interactive control module allows a human operator to select one of a plurality of memories for coupling to the automotive computer to control engine performance. User on-site customization of the engine control program is permitted by allowing direct downloading of an engine control program into the automotive computer through the operator interactive control.

Abstract: A method for diagnosing an engine (102) including the steps of sensing a first set of parameters of the engine (102) and determining a modeled value of a first operating characteristic. A second set of parameters of the engine (102) is sensed and used to determined a modeled value of a second operating characteristic. The modeled values are compared to actual values and the engine is responsively diagnosed.

Abstract: An engine control system is provided which calculates an optimum air/fuel ratio by minimizing the smoke produced by the engine while at the same time maximizing the engine response time for all altitudes over which the engine operates. The control system includes a microprocessor, an ambient pressure sensor, fuel injectors, and storage means. A manual adjustment is provided that allows an operator to manually adjust the air/fuel ratio within certain pre-defined limits of the optimum value.

Abstract: An apparatus for controlling an air-fuel ratio in a lean burn internal combustion engine, such that three different air-fuel ratio zones are set, the three zones being an ultra lean zone with a low load, a medium lean zone with a medium load, and a non-lean zone with a high load. When the engine is under low load conditions, a map FLEANPM is selected to obtain an ultra lean air-fuel ratio based on detected intake pressure PM values and engine speed NE. When the engine is under medium load conditions, a map FLEANTA is selected to obtain a medium lean air-fuel ratio based on a detected throttle opening values TA and engine speed NE. When the engine is under high load, conditions the lean correction control is canceled, thereby obtaining a theoretical air-fuel ratio or an air-fuel ratio smaller than the theoretical air-fuel ratio, and when the engine remains at a point in the medium lean zone, the air-fuel ratio decreases gradually toward the theoretical air-fuel ratio as time elapses.

Abstract: A system for controlling fuel metering in an internal combustion engine using a fluid dynamic model and the cylinder air flow past the throttle is determined therefrom. Based on the observation that the difference between a steady-state engine operating condition and a transient engine operating condition can be described as the difference in the effective throttle opening areas, the amount of fuel injection is determined from the product of the ratio between the areas and a basic fuel injection amount under the steady-state engine operating condition obtained by mapped data retrieval and by subtracting a correction amount corresponding to an air flow filling a chamber between the throttle and the cylinder from the product. Under steady-state engine operation, the correction amount becomes zero.

Abstract: A fuel injection control device controls the calculated fuel injection quantity depending upon the load condition of the engine such that the fuel injection quantity demanded by the engine can be established. This fuel injection quantity is determined based upon engine speed, intake air temperature, engine temperature, the atmospheric pressure of the intake air, and the throttle opening. When the detected intake air temperature is high for a high load condition of the engine, an intake air temperature correction factor is set such that the intake air temperature is less influential upon the establishment of the fuel injection quantity. Moreover, during acceleration, an acceleration incremental fuel injection quantity is calculated based upon different water temperature correction factors. When an engine temperature is low, the fuel injection quantity demanded by the engine is very large.

Abstract: A control apparatus for a marine engine capable of effectively suppressing a great variation in the rotational speed of the engine due to a great variation in an intake air pressure particularly when the engine is trolling. In one form, an air/fuel ratio of a mixture supplied to the engine is made constant to maintain engine output power at a constant level. In another form, the intake air pressure, based on which the engine is controlled, is averaged in such a manner as to reduce a variation in the engine rotational speed by using a greater averaging coefficient during trolling than at other times. In a further form, if a variation in the intake air pressure is less than a predetermined value, the intake air pressure is used for controlling the engine, whereas if otherwise, another engine operating parameter such as an opening degree of a throttle valve is used instead of the intake air pressure.

Abstract: The ability of an automotive computer for controlling an engine is enhanced by allowing the automotive computer to be controlled by an arbitrarily selected one of a plurality of engine control programs according to arbitrary driver discretion. The bus connecting the computer and memory of a conventional automotive computer is connected to a computer controlled operator interactive control module and an expanded memory. The operator interactive control module allows a human operator to select one of a plurality of memories for coupling to the automotive computer to control engine performance. User on-site customization of the engine control program is permitted by allowing direct downloading of an engine control program into the automotive computer through the operator interactive control.

Abstract: A fuel injection device increases an increment value of fuel after cut-off of assist air so that the air/fuel ratio for combustion can be held constant to stabilize the idling rotational speed. The device has control means for controlling, based on various detection signals indicative of an engine cooling water temperature, an engine rotational speed, an amount of intake air, etc., a valve-opening time of a fuel injection valve in accordance with a predetermined control program, and also controlling an on/off control valve for cutting off air supplied to fuel atomizing means. Fuel incrementing means increases an amount of liquid fuel supplied to the fuel injection valve depending on opening/closing of the on/off control valve and the temperature of engine cooling water. When the on/off control valve is closed and an engine is in a state of steady operation, the increment value of the liquid fuel supplied to the fuel injection valve can be gradually increased by the fuel incrementing means.

Abstract: A defect of prior art methods for controlling an internal combustion engine based on families of characteristics depending on pressure and rpm is that an air mass being taken in is a function of an air temperature in a cylinder and thus of heating in an intake section. This defect is corrected according to the invention by multiplying a basic fuel value taken from a basic family of characteristics by a factor having a denominator containing a correction temperature being determinative for heating-up the intake air in the intake section as a function of its temperature and of an air flow and being taken from a corresponding family of temperature characteristics.

Abstract: In a fuel control device for an internal combustion engine wherein an estimated pressure (Pi) in the engine intake manifold is calculated by digital filtering an output signal from a H/W sensor by making use of a difference equation, an air flow rate (Qc) at the engine cylinder port is estimated based upon a detected engine rotating number (N) and the calculated estimated pressure (Pi) by retrieving a value of air flow rate from a map defined by the engine rotating number (N) and the estimated pressure (Pi) in the engine intake manifold. Then, the fuel quantity (Tp) to be injected is calculated based upon a detected engine rotating number (N) and the estimated air flow rate (Qc) at the engine cylinder port. However during the engine starting period, a learned estimated pressure in the engine intake manifold is used instead of the calculated estimate pressure (Pi) in the engine intake manifold to determined the retrieved estimated air flow rate (Qc).

Abstract: The ability of an automotive computer for controlling an engine is enhanced by allowing the automotive computer to be controlled by an arbitrarily selected one of a plurality of engine control programs according to arbitrary driver discretion. The bus connecting the computer and memory of a conventional automotive computer is connected to a computer controlled operator interactive control module and an expanded memory. The operator interactive control module allows a human operator to select one of a plurality of memories for coupling to the automotive computer to control engine performance. User on-site customization of the engine control program is permitted by allowing direct downloading of an engine control program into the automative computer through the oeprator interactive control.

Abstract: A lean burn internal combustion engine has a basic fuel injection amount calculated and multiplied by a lean correction factor, the resulting amount controls the air fuel ratio of the engine. The lean correction multiplied by factor is calculated from a first map based on intake pressure and engine speed. However, when the degree of opening of the throttle valve is larger than a predetermined value, a second correction map based on the degree of opening of the throttle valve and engine speed is used to obtain the lean correction factor. When the second correction map is employed, an ignition timing map based on the degree of opening of the throttle valve and engine speed is used to obtain an ignition timing; instead of the usual ignition timing, based on intake pressure and engine speed.

Abstract: In a method of monitoring the emission of nitrogen oxides NO.sub.x in the exhaust gas of an internal combustion engine, the engine to be monitored incorporates an accelerometer used as a sensor. The signals produced by the accelerometer are analyzed to determine the NO.sub.x concentration in the engine exhaust gas by comparison with data supplied by an accelerometer fitted to a control engine.

Abstract: An air/fuel mixture ratio learning control system for an internal combustion engine using a mixed fuel employs a learnt correction coefficient which is used both in a FEEDBACK mode air/fuel ratio control and in an OPEN LOOP mode air/fuel ratio control. The learnt correction coefficient is derived based on a FEEDBACK air/fuel ratio dependent correction coefficient per one of preselected engine driving ranges and per one of preselected concentration ranges of one fuel component contained in the mixed fuel. The learnt correction coefficient is cyclically derived in a preselected stable engine driving condition during the FEEDBACK mode air/fuel ratio control for updating a previously derived and stored one to minimize a deviation of the FEEDBACK correction coefficient from a reference value.

Abstract: A fuel injection controlling device for a two-cycle engine comprising an air manifold; a throttle valve; a fuel injector; a fuel supply system including a fuel pump; a battery voltage sensor; an air temperature sensor; an engine speed sensor; a timing sensor; a barometric pressure sensor; a throttle position sensor; a first data processor for receiving and processing sensing signals for determining fuel injector duration and timing and fuel pump operating speed; a first data processor temperature sensor for sensing the relative temperature of certain electronic components in the first data processor; a heater operatively associated with the first data processor electronic components for selectively heating the electronic components; and a second data processor operable independently of the first data processor for receiving an electronic component temperature sensing signal and for generating a control signal to the heater responsive thereto for heating the components when the temperature thereof is below a p