Abstract: An injection control device for a fuel injection valve includes: a current detection unit of the fuel injection valve; a current area correction control unit that performs current area correction for an area correction amount of an energization time to equalize the integrated current value of the energization current profile and an integrated current value of the detected current; and an information correction unit that learns and stores a reference attainment time, from a start of energization to an attainment of each of the plurality of reference currents, in a storage unit, and corrects information related to the current area correction based on a difference between the reference attainment time and an actual attainment time from the start of energization to the attainment of each reference current.

Abstract: A system may include at least one processor configured to receive a fuel signal indicative of an amount of fuel supplied to a cylinder of an internal combustion engine, receive an air signal indicative of a quantity of air supplied to the cylinder, and estimate a mean effective pressure in the cylinder based at least in part on the fuel signal and the air signal. The system may estimate an exhaust gas temperature for exhaust gas entering an exhaust manifold associated with the internal combustion engine, generate a rate of temperature change value for the exhaust manifold based at least in part on the exhaust gas temperature, generate an estimated exhaust manifold temperature based at least in part on the rate of temperature change value for the exhaust manifold, and estimate an exhaust gas temperature for exhaust gas exiting the exhaust manifold and entering a turbine of a turbocharger.

Abstract: In a diesel engine, displacement of an amount of fuel injection is calculated on the basis of a reference amount of heat production and an actual amount of heat production, and an amount of fuel injection from an injector is corrected on the basis of the displacement of an amount of fuel injection. Displacement of a heat production rate gradient is calculated by subtracting an actual heat production rate gradient from a reference heat production rate gradient, displacement of an amount of intake air on the basis of the displacement of heat production rate gradient and the displacement of the amount of fuel injection, and the amount of intake air is corrected by adjusting a supercharging pressure of a turbocharger on the basis of the displacement of the amount of intake air. Accordingly, it is possible to adjust the amount of fuel injection and the amount of intake air.

Abstract: When a catalyst of an internal combustion engine is not activated, a control apparatus retards the ignition timing of a spark plug, and thereby, executes a rapid warm-up control of the catalyst. However, on this occasion, when alcohol concentration Ca is high, the control apparatus sets the ignition timing to a more advanced side than when the alcohol concentration Ca is low. When the ignition timing is set to an advanced side, opening angle ? of a throttle valve is manipulated such that command value qsjc for the quantity of the air that is filled into a combustion chamber is increased. Thereby, compared with when the command value qsjc is not increased, the quantity of the fuel that is injected from a cylinder injection valve increases, and the thermal energy of exhaust gas increases.

Abstract: A method of operating an engine is provided. The method includes determining a temperature and a pressure of intake air, and a temperature and a pressure of exhaust generated by the engine. The method includes determining a work performed by the engine based at least on an engine speed of the engine, and determining heating losses of the engine. The method includes determining an enthalpy of the intake air based at least on the work, the heating losses, a heating value of a fuel used for combustion within the engine, and the temperature and the pressure of the exhaust. The method includes determining a humidity value of the intake air based on the enthalpy, temperature and pressure of the intake air and determining an amount of NOx based on the humidity value. The method further includes controlling an operation of the engine based on the determined amount of NOx.

Abstract: A fuel system that in at least some implementations includes a carburetor having a fluid passage, a solenoid, a valve, a driver circuit and a control circuit. The valve may be moved by the solenoid between an open position permitting fluid flow through the fluid passage and a closed position at least partially inhibiting fluid flow through the fluid passage. The driver circuit and control circuit are communicated with the solenoid to contribute to providing power to the solenoid and controlling actuation of the solenoid. The driver circuit and control circuit provide a first magnitude of power to the solenoid to initially change the solenoid from its closed position to its open position and a second magnitude of power to maintain the solenoid in its open position wherein the second magnitude of power is less than the first magnitude.

Abstract: An object of the invention is to provide a technology pertaining to a control system for an internal combustion engine using CNG to allow an internal combustion engine to operate appropriately even when properties of CNG change. To achieve the object, in the control system for an internal combustion engine using compressed natural gas according to the invention, when air-fuel ratio feedback control that corrects the fuel injection quantity in such a way as to make the air-fuel ratio of the air-fuel mixture burned in the internal combustion engine substantially equal to a target air-fuel ratio, a control parameter relating to a condition of combustion of the air-fuel mixture is corrected based on the magnitude of the correction value in the air-fuel ratio feedback control.

Abstract: A method of monitoring a particulate filter of an exhaust aftertreatment device includes sensing a first pressure drop across the particulate filter at a first instant in time, and sensing a second pressure drop across the particulate filter at a second instant in time. A controller may then calculate a rate-of-change of the pressure drop between the first instant in time and the second instant in time while sensing a flow rate of an exhaust gas flowing through the exhaust aftertreatment device. Using the sensed exhaust flow rate, the controller may determine a rate-of-change threshold, and subsequently compare the calculated rate-of-change to the rate-of-change threshold. The method further includes updating a soot model using the sensed second pressure drop if the calculated rate-of-change is less than the rate-of-change threshold.

Abstract: A control system for an engine includes a spark module and a fuel module. The spark module advances spark timing of a cylinder R degrees past a spark limit for N consecutive cylinder firing events, and retards spark timing of the cylinder past the spark limit for M consecutive cylinder firing events after the N consecutive cylinder firing events. The fuel module supplies a rich fuel-air charge to the cylinder for the M consecutive cylinder firing events. According to the system, R is a real number greater than zero, N and M are integers greater than zero, and the spark limit is a control value used to limit an amount of spark advance to prevent spark-knock. A method for controlling an engine is also provided.

Abstract: Various methods and arrangements for controlling catalytic converter temperature are described. In one aspect, an engine controller includes a catalytic monitor and a firing timing determination unit. The catalytic monitor obtains data relating to a temperature of a catalytic converter. Based at least partly on this data, the firing timing determination unit generates a firing sequence for operating the engine in a skip fire manner. Another aspect of the invention relates to an engine exhaust system that can help expedite the heating of a catalytic converter.

Abstract: A control apparatus for an internal combustion engine having a throttle valve disposed in an intake passage of the engine is provided. A wide-open intake air amount, which is an intake air amount corresponding to a state where the throttle valve is fully opened, is calculated, and a theoretical intake air amount, which is an intake air amount corresponding to a state where no exhaust gas of the engine is recirculated to a combustion chamber of the engine, is calculated according to the wide-open intake air amount and the intake pressure. An air-fuel ratio correction amount and a learning value thereof are calculated according to the detected air-fuel ratio, and a reference intake air amount is calculated using the intake pressure, the engine rotational speed, the air-fuel ratio correction amount, and the learning value.

Abstract: The disclosure provides a method of detecting and inhibiting an abnormal combustion event in an internal combustion engine, comprising operating the internal combustion engine to produce exhaust gas from the cylinder at a break mean effective pressure greater than or equal to 10 bars at a speed less than or equal to 2,000 revolutions per minute; monitoring the exhaust gas from the cylinder with an oxygen sensor while the internal combustion engine undergoes a pre-ignition combustion event; obtaining an output from the oxygen sensor, the output from the oxygen sensor providing an indicator of the pre-ignition combustion event; and adjusting at least one operating parameter of the internal combustion engine in response to the output of the oxygen sensor, wherein the at least one operating parameter is adjusted to inhibit an occurrence of a subsequent pre-ignition combustion event.

Abstract: A method for controlling a multi-cylinder direct-injection internal combustion engine includes establishing an external exhaust gas recirculation valve from a present position to a target position to achieve a target exhaust gas recirculation, and synchronizing combustion initiation timing with actual exhaust gas recirculation as actual exhaust gas recirculation changes from a first exhaust gas recirculation value corresponding to the present position of the external exhaust gas recirculation valve to a second exhaust gas recirculation value corresponding to the target position of the external exhaust gas recirculation valve.

Abstract: An internal combustion engine control device is provided which can accurately estimate intake pipe temperature behavior during transient time even in an internal combustion engine embedded with a variable valve or a turbocharger. The internal combustion engine control device estimates transient behavior of the intake pipe temperature, on the basis of a flow rate (dGafs/dt) of gas flowing into the intake pipe, a flow rate (dGcyl/dt) of gas flowing from the intake pipe, an intake pipe pressure Pin, and a temporal changing rate (dPin/dt) of the intake pipe pressure. The device performs knocking control during transient time, on the basis of the estimated transient behavior of the intake pipe temperature.

Abstract: Disclosed is a control device that is used for an internal combustion engine and capable of periodically varying an air-fuel ratio while keeping torque generated by the internal combustion engine at a target torque. The control device can periodically vary a target air-fuel ratio and controls a fuel injection amount in accordance with the target air-fuel ratio which periodically varies. Further, the control device sets an air amount control torque in accordance with the target torque and calculates a target air amount for achieving the air amount control torque at a predetermined virtual air-fuel ratio. The control device then provides air amount control in accordance with the target air amount and calculates an air amount that is estimated to be achieved by the air amount control.

Abstract: An accumulating portion suspends the accumulation of an airflow meter output and a timer suspends the time count when a clutch semi-engagement detection signal is being output from a clutch semi-engagement detection portion. Thus, the airflow meter output obtained while the clutch semi-engagement detection signal was being output is excluded from the calculation of a total intake air amount. A comparing portion compares the calculated total intake air amount with a reference value obtained from a reference value setting portion. If the total intake air amount is smaller than the reference value, the Cold Start Strategy (CSS) control is determined as being abnormal and a CSS-abnormality signal is output.

Abstract: A system for filtering and oxidizing particulate matter produced by a gasoline direct injection engine is disclosed. In one embodiment, engine spark is controlled such that soot held by a particulate filter may be oxidized even during low engine loads.

Abstract: An engine control apparatus which may be employed in automotive vehicles. The engine control apparatus is equipped with a controlled variable arithmetic expression which defines correlations between combustion parameters associated with combustion conditions of an engine and controlled variables actuators for an operation of the engine. This eliminates the need for finding relations of optimum values of the controlled variables to the combustion parameters through adaptability tests, which results in a decrease in burden of an adaptability test work and a map-making work on manufacturers. The engine control apparatus also works to learn or optimize the controlled variable arithmetic expression based on actual values of the combustion parameters, thereby avoiding undesirable changes in correlations, as defined by the controlled variable arithmetic expression, due to a change in environmental condition.

Abstract: A system and method for operating an engine having ionization signal sensing include detecting plug fouling and controlling the engine using progressively more aggressive control strategies if the fouling condition persists. A first control strategy may be used when the number of engine starts or running time are below corresponding thresholds and a second strategy otherwise. The first strategy may employ progressively more aggressive control procedures to eliminate spark plug deposits that may include repetitive sparking, exhaust cycle sparking, increasing engine loading, advancing spark timing, increasing air/fuel ratio, and increasing idle speed, for example. The second strategy may include similar corrective actions employed in a different order and/or to a lesser degree in an attempt to eliminate plug fouling without any noticeable change in engine operation or performance as perceived by the vehicle operator.

Abstract: A control method of a spark ignition engine and a spark ignition engine capable of warming up an engine more promptly while promptly activating a catalyst are provided. Implemented is the control of igniting a mixture at an ignition timing that is set on a more lag side than an MBT, which is an ignition timing in which an output torque of the engine becomes maximum until the catalyst 62 is activated after the engine is started. After the catalyst 62 is activated, until the engine is warmed up control of increasing a ratio of burned gas contained in the mixture within the combustion chamber 14 to be more than the ratio of the burned gas in the mixture during a first period, and control of igniting the mixture containing more burned gas than the burned gas in the first period are implemented.

Abstract: An engine control apparatus which may be employed in automotive vehicles. The engine control apparatus is equipped with at least one of a combustion parameter or a controlled variable arithmetic expression. The combustion parameter arithmetic expression defines combustion conditions of the engine needed to achieve required values of engine output-related values such as exhaust emissions. The controlled variable arithmetic expression defines how to operate actuators for an operation of the engine to meet desired combustion conditions of the engine. The use of the combustion parameter or controlled variable arithmetic expression achieves simultaneous agreement of the engine output-related values with required values without mutual interference between combustion parameters associated with the combustion conditions.

Abstract: A system for filtering and oxidizing particulate matter produced by a gasoline direct injection engine is disclosed. In one embodiment, engine spark is controlled such that soot held by a particulate filter may be oxidized even during low engine loads.

Abstract: A system for filtering and oxidizing particulate matter produced by a gasoline direct injection engine is disclosed. In one embodiment, engine spark is controlled such that soot held by a particulate filter may be oxidized even during low engine loads.

Abstract: A system and method for operating an engine having ionization signal sensing include detecting plug fouling and controlling the engine using progressively more aggressive control strategies if the fouling condition persists. A first control strategy may be used when the number of engine starts or running time are below corresponding thresholds and a second strategy otherwise. The first strategy may employ progressively more aggressive control procedures to eliminate spark plug deposits that may include repetitive sparking, exhaust cycle sparking, increasing engine loading, advancing spark timing, increasing air/fuel ratio, and increasing idle speed, for example. The second strategy may include similar corrective actions employed in a different order and/or to a lesser degree in an attempt to eliminate plug fouling without any noticeable change in engine operation or performance as perceived by the vehicle operator.

Abstract: A control system includes: a detecting device that detects the transition in the cumulative amount of heat generated in a combustion chamber based on the pressure in the combustion chamber in an expansion stroke; and a controller that controls the amount of exhaust gas contained in an air-fuel mixture in the combustion chamber such that the amount of change in the cumulative amount of heat generated in the combustion chamber through a predetermined crank angle range will become a predetermined value.

Abstract: An engine control system comprises an actuator control module and a tertiary injection module. The actuator control module provides secondary air to an exhaust system when a catalyst light-off mode is enabled and provides first and second injections of fuel to a cylinder during each engine cycle while the catalyst light-off mode is enabled. The tertiary injection module selectively provides a third injection of fuel to the cylinder during an exhaust phase of each engine cycle while the catalyst light-off mode is enabled. The first, second, and third injections are each separated by a period of time.

Abstract: An engine control system includes an air control module, a spark control module, a torque control module, a transient detection module, and a launch torque module. The air control module controls a throttle valve of an engine based on a commanded predicted torque. The spark control module controls spark advance of the engine based on a commanded immediate torque. The torque control module increases the commanded predicted torque when a catalyst light-off (CLO) mode is active, and increases the commanded immediate torque when a driver actuates an accelerator input. The transient detection module generates a lean transient signal when an air per cylinder increase is detected while the CLO mode is active. The launch torque module generates a torque offset signal based on the lean transient signal. The torque control module increases the commanded immediate torque based on the torque offset signal.

Abstract: Multi-cylinder internal combustion engine wherein the intake valves, the injector means and the ignition means are controlled so as to adjust the enthalpy value of the exhaust gases produced by each cylinder independently from the other cylinders.

Abstract: A control device of an internal combustion engine calculates ignition delays in lean combustion and rich combustion, standardizes the ignition delays based on ignition timing, and further standardizes the ignition delays based on injection quantity and injection timing of pilot injection respectively. The control device calculates a present ignition delay by linear interpolation of the standardized ignition delays in the lean combustion and the rich combustion. Moreover, the control device corrects the present ignition delay with the ignition timing and further corrects the present ignition delay with the injection quantity and the injection timing of the pilot injection. The control device calculates a command value of the injection timing by subtracting the corrected present ignition delay from target ignition timing.

Abstract: A controller of an engine that can use a blended fuel with alcohol blended therein, the controller includes: an ignition timing controller, operable to control an ignition timing of the engine; an exhaust air-fuel ratio detector, operable to detect an exhaust air-fuel ratio of the engine; a concentration detector, operable to detect concentration of the alcohol in the blended fuel; an operation state detector, operable to detect an operation state of the engine; and a corrector, when the operation state which is detected by the operation state detector is a high-speed, high-load operation state, as the concentration of the alcohol which is detected by the concentration detector is higher, operable to control an injection amount which is injected from a fuel injection valve to correct a target equivalence ratio more in a lean direction, and operable to correct the ignition timing which is controlled by the ignition timing controller more to a spark advance side.

Abstract: A control system includes: a detecting device that detects the transition in the cumulative amount of heat generated in a combustion chamber based on the pressure in the combustion chamber in an expansion stroke; and a controller that controls the amount of exhaust gas contained in an air-fuel mixture in the combustion chamber such that the amount of change in the cumulative amount of heat generated in the combustion chamber through a predetermined crank angle range will become a predetermined value.

Abstract: A hybrid vehicle propulsion system is disclosed comprising an engine having at least one combustion cylinder configured to operate in a first and a second combustion mode, wherein the first combustion mode is a spark ignition mode and the second combustion mode is a compression ignition mode, wherein the engine is configured to supply an engine output; a motor configured to selectively supply or absorb a secondary output; an energy storage device configured to selectively store at least a portion of the engine output and selectively supply energy to the vehicle; a lean NOx trap configured to store NOx produced by the engine; and a controller configured to control at least the engine, the motor, and the energy storage device, wherein the controller is configured to selectively operate said at least one combustion cylinder in one of the spark ignition mode and the compression ignition mode based on a condition of the lean NOx trap.

Abstract: A control apparatus retards ignition timing of the engine, and increases an amount of a fuel supplied to the engine based on a retard amount of the ignition timing, by calculating a maximum engine intake air amount at which an exhaust system temperature can be maintained at or below a predetermined upper limit temperature by increasing the amount of the fuel supplied to the engine without causing a misfire of the engine, and limiting an engine intake air amount to a value no greater than the maximum engine intake air amount.

Abstract: A compression ignition internal combustion engine includes injectors, each of which injects fuel into a corresponding cylinder. An ECU determines target ignition timing based on engine operational information and adjusts fuel injection start timing and a fuel injection quantity of each injector based on the target ignition timing. The engine further includes an air/fuel ratio sensor, which senses an oxygen concentration of exhaust gas. The ECU corrects the target ignition timing based on the oxygen concentration, which is sensed with the air/fuel ratio sensor, with reference to a predefined relationship between the oxygen concentration and ignition timing for achieving a generally equal constant torque of the engine.

Abstract: Super retard combustion is performed in which an ignition timing is set to be after a compression top dead center and fuel is injected before the ignition timing and after the compression top dead center, at cold start or the like which requires early warming-up of a catalyst. During an idle operation without the super retard combustion, a first ISC control is executed in which a feedback control is provided for the degree of opening of a throttle and the ignition timing so that an engine speed corresponds to a target idle speed (S14). On the other hand, during the super retard combustion, a second ISC control is executed in which the control of the degree of opening of the throttle is inhibited, but the ignition timing is advanced because a catalyst may be thermally damaged when the amount of intake air is increased in accordance with an increase in load of an auxiliary device and the like (S15).

Abstract: A compression ignition internal combustion engine includes injectors, each of which injects fuel into a corresponding cylinder. An ECU determines target ignition timing based on engine operational information and adjusts fuel injection start timing and a fuel injection quantity of each injector based on the target ignition timing. The engine further includes an air/fuel ratio sensor, which senses an oxygen concentration of exhaust gas. The ECU corrects the target ignition timing based on the oxygen concentration, which is sensed with the air/fuel ratio sensor, with reference to a predefined relationship between the oxygen concentration and ignition timing for achieving a generally equal constant torque of the engine.

Abstract: An engine control strategy that ensures that NOx emissions from the engine will be maintained at an acceptable level. The control strategy is based on a two-dimensional fuel-air curve, in which air manifold pressure (AMP) is a function of fuel header pressure and engine speed. The control strategy provides for closed loop NOx adjustment to a base AMP value derived from the fuel-air curve.

Abstract: This feature of the present invention comprises a method and apparatus to retard the spark time. As a result, the catalyst heats up quickly during the cold start. The retard spark control method of the present invention uses a closed loop to adjust the engine retard limit during an engine cold start to retard the engine spark as much as possible without engine misfire and with minimum partial burn. The increased exhaust temperature heats up the catalyst more quickly than conventional open loop approaches, which as a result, reduces hydrocarbon emissions. The closed loop retard spark control using ionization current feedback consists of four major components or functions, an error and gain generator, a proportional and integration control processing block, a default spark timing processor, and an adaptive learning apparatus.

Abstract: A method for improving engine performance, by increasing fuel efficiency and/or power output, and/or by decreasing the output of pollutants. When the temperature of the engine's exhaust system is lower than a target temperature, the ignition position of the cylinders of the engine is changed such that fuel and air propagate from the cylinders into the exhaust system while undergoing combustion. The heat from the combustion of the fuel and air in the exhaust system increases the temperature of the exhaust system. The ignition position may be retarded from the normal operating ignition position by up to 40 degrees or more, or to 10 to 20 degrees after top dead center. The ignition position may be changed manually or automatically. The exhaust temperature may be sensed and displayed. An engine control system for improving engine performance includes an ignition changing mechanism to change the ignition position of the cylinders, and an activating mechanism for activating the ignition changing mechanism.

Abstract: A system and method for controlling ignition timing of an engine is provided. The method includes determining a change in a combustion temperature rise within an engine based on a change in at least one engine operating parameter. The method further includes adjusting the ignition timing of the engine based on the change of combustion temperature rise.

Abstract: A method for improving engine performance, by increasing fuel efficiency and/or power output, and/or by decreasing the output of pollutants. When the temperature of the engine's exhaust system is lower than a target temperature, the ignition position of the cylinders of the engine is changed such that fuel and air propagate from the cylinders into the exhaust system while undergoing combustion. The heat from the combustion of the fuel and air in the exhaust system increases the temperature of the exhaust system. The ignition position may be retarded from the normal operating ignition position by up to 40 degrees or more, or to 10 to 20 degrees after top dead center. The ignition position may be changed manually or automatically. The exhaust temperature may be sensed and displayed. An engine control system for improving engine performance includes an ignition changing mechanism to change the ignition position of the cylinders, and an activating mechanism for activating the ignition changing mechanism.

Abstract: The temperature protection method for a motor vehicle exhaust pipe comprises steps of determining a minimum ignition angle from several possible values, including a stalling-speed angle, on the basis of predetermined logic and of engine operating parameters.

Abstract: An arrangement for regulating a spark-ignition internal combustion engine, in particular a stationary boosted gas Otto-cycle engine, comprising a power regulating device acting on at least one power setting member, wherein an ignition time regulating device (8, 9, 10) adjusts the ignition time (ZZP) in dependence on the position of the power setting member (2).

Abstract: The invention concerns a temperature protection method for a motor vehicle engine exhaust pipe, comprising steps which consist in determining an ignition advance angle among several possible values including a stall speed angle, based on a predetermined logic and operational parameters of the engine.

Abstract: A system and method for controlling ignition timing of an engine is provided. The method includes determining a change in a combustion temperature rise within an engine based on a change in at least one engine operating parameter. The method further includes adjusting the ignition timing of the engine based on the change of combustion temperature rise.

Abstract: A method for rapidly heating an emission control device in an engine exhaust uses excess air added to the exhaust via an air introduction device. After an engine cold start, the engine is operated to raise exhaust manifold temperature to a first predetermined value by operating the engine with a lean air-fuel ratio and retarded ignition timing. Once the exhaust manifold reaches the predetermined temperature value, the engine is switched to operate rich and air is added via the air introduction device. The added air and rich exhaust gas burn in the exhaust, thereby generating heat and raising catalyst temperature even more rapidly. The rich operation and excess air are continued until either engine airflow increases beyond a pre-selected value, or the emission control device reaches a desired temperature value. After the emission control device reaches the desired temperature, the engine is operated substantially around stoichiometry.

Abstract: A process for determining an operating parameter of an internal combustion engine as a function of three control parameters (N, P, &lgr;) of this motor, comprises: a) establishing a first map of the operating parameter as a function of two control parameters, the third control parameter being fixed at a first value; b) establishing a second map of the operating parameter as a function of the two same control parameters, the third control parameter being fixed at a second value; c) establishing a relationship between the operating parameter and the third control parameter over all the range of variation of this parameter at at least one specific operating point; and d) using this relationship to determine the operating parameter as a function of the three control parameters at all points of operation of the motor.

Abstract: A method and an apparatus for protecting the catalytic converter in the exhaust system of an internal combustion engine from overheating in the case of retarded ignition angles, in which a characteristic map (10) provides an engine-speed- and/or load-dependent ignition angle (Zu) that can be specified without time restriction. The ignition angle (Zu) is compared in a comparison device (12) with an optimum ignition angle (OZ) calculated in a parameter-dependent manner and, in the case of an optimum ignition angle (OZ) that is more retarded than the unrestricted specifiable ignition angle (Zu), this optimum ignition angle (OZ) is used for ignition of the internal combustion engine during specifiable time periods in alternation with the ignition angle (Zu), which can be specified without time restriction, while, in the opposite case, only the optimum ignition angle (OZ) is used for this purpose.

Abstract: A system and method of controlling an engine includes sensing a concentration of NOx in exhaust gases produced by the engine and generating a sensed NOx value representative thereof, and controlling an engine control set point as a function of the sensed NOx value. The system also calculates a NOx difference value by subtracting a base NOx value from the sensed NOx value, and if an absolute value of the difference value exceeds a threshold, modifying the set point as a function of the NOx difference value. The method also includes sensing engine RPM, sensing engine manifold absolute pressure (MAP), determining the NOx value as a function of sensed engine RPM and MAP.

Abstract: A two-cycle internal combustion engine has an ignition timing that varies with engine speed. A plurality of ignition patterns (the relationship between ignition timing and engine speed) are used. The engine exhaust gas temperature is sensed and is used to determine the particular ignition pattern used at a particular time.