Methods and systems are provided for reducing blackening of an oxygen sensor due to voltage excursions into an over-potential region. Before transitioning the sensor from a lower voltage to an upper voltage during variable voltage operation, an operating temperature of the sensor is reduced via adjustments to a sensor heater setting. The reduction in temperature increases the range of temperatures available to the sensor before the over-potential region is entered.

Systems and techniques for identifying abnormal exhaust valve performance of an internal combustion engine may include receiving exhaust passage temperature signals from a plurality of exhaust passage temperature sensors, each exhaust passage being fluidly connected to one or more exhaust valves of the internal combustion engine, the exhaust passage temperature signals being indicative of respective exhaust passage temperatures. The method may further include comparing one or more of the exhaust passage temperatures, identifying a caution exhaust passage temperature, from one or more of the exhaust passage temperatures, that deviates from one or more of the other one or more exhaust passage temperatures, and outputting an abnormal exhaust valve performance indication based on identifying the caution exhaust passage temperature.

A method for analyzing a fluid that flows from a chamber, in particular a combustion chamber, of an internal combustion engine into a fluid guide. The internal combustion engine includes at least one element, in particular an injector, for the supply of fuel. The analysis takes place with the aid of a sensor, in particular a lambda sensor, on which the fluid in the fluid guide acts. The analysis takes place during cranking of the internal combustion engine, and the fluid acting on the sensor is not influenced by fuel that is supplied in a controlled manner.

An internal combustion engine comprises an engine body, a filter provided in an exhaust passage of the engine body and trapping particulate matter in the exhaust, and a temperature sensor detecting a temperature of gas flowing cut from the filter. A control device controlling this internal combustion engine comprises a fuel cut control pan configured to perform fuel cut control stopping a supply of fuel to a combustion chamber of the engine body and a forced ending part configured to forcibly make the fuel cut control end even if a condition for performance of fuel cut control had stood based on a trend in change of temperature of the gas temperature detected by the temperature sensor.

The invention relates to a method to heat exhaust gases to a selected specific temperature by fuel injection control in an internal combustion engine (112), which engine comprises a control unit (115) registering the currently requested load and determining a required fuel amount in response to the requested load. The method involves registering low load operation of the internal combustion engine; registering an input from at least one exhaust after-treatment system (121) sensor indicating a detected condition; determining an exhaust temperature requirement for the detected condition and calculating a target exhaust temperature; selecting a group of cylinders to be regulated for achieving the target exhaust temperature; calculating a ratio for desired 1.sup.st and 2.sup.nd fuel amounts to be injected alternately in consecutive induction strokes for the selected group of cylinders to achieve the target exhaust temperature; wherein the ratio defines an offset between an increased 1.sup.st fuel amount to be injected in a cylinder of the selected group of cylinders for every second induction stroke, and a reduced 2.sup.nd fuel amount to be injected for the intermediate induction strokes.

The invention relates to a method to heat exhaust gases to a selected specific temperature by fuel injection control in an internal combustion engine (112), which engine comprises a control unit (115) registering the currently requested load and determining a required fuel amount in response to the requested load. The method involves registering low load operation of the internal combustion engine; registering an input from at least one exhaust after-treatment system (121) sensor indicating a detected condition; determining an exhaust temperature requirement for the detected condition and calculating a target exhaust temperature; selecting a group of cylinders to be regulated for achieving the target exhaust temperature; calculating a ratio for desired 1.sup.st and 2.sup.nd fuel amounts to be injected alternately in consecutive induction strokes for the selected group of cylinders to achieve the target exhaust temperature; wherein the ratio defines an offset between an increased 1.sup.st fuel amount to be injected in a cylinder of the selected group of cylinders for every second induction stroke, and a reduced 2.sup.nd fuel amount to be injected for the intermediate induction strokes.

A two-stroke engine (4) has a throttle motor (22) for driving a throttle valve (20), a fuel injection device (430) disposed in an intake system (18) including a crank chamber (420), and a control unit (24) controlling the throttle motor (22) and the fuel injection device. The two-stroke engine (4) is designed to achieve an engine rotation speed of 4,500 rpm to 7,000 rpm when the throttle valve (20) is fully open. The two-stroke engine (4) is operated with the throttle full open by the control unit (24), and a battery (8) is charged with electric power generated by a generator (6) using the two-stroke engine.

A two-stroke engine (4) has a throttle motor (22) for driving a throttle valve (20), a fuel injection device (430) disposed in an intake system (18) including a crank chamber (420), and a control unit (24) controlling the throttle motor (22) and the fuel injection device. The two-stroke engine (4) is designed to achieve an engine rotation speed of 4,500 rpm to 7,000 rpm when the throttle valve (20) is fully open. The two-stroke engine (4) is operated with the throttle full open by the control unit (24), and a battery (8) is charged with electric power generated by a generator (6) using the two-stroke engine.

An internal combustion engine comprises an engine body, a filter provided in an exhaust passage of the engine body and trapping particulate matter in the exhaust, and a temperature sensor detecting a temperature of gas flowing cut from the filter. A control device controlling this internal combustion engine comprises a fuel cut control pan configured to perform fuel cut control stopping a supply of fuel to a combustion chamber of the engine body and a forced ending part configured to forcibly make the fuel cut control end even if a condition for performance of fuel cut control had stood based on a trend in change of temperature of the gas temperature detected by the temperature sensor.

A method for analyzing a fluid that flows from a chamber, in particular a combustion chamber, of an internal combustion engine into a fluid guide. The internal combustion engine includes at least one element, in particular an injector, for the supply of fuel. The analysis takes place with the aid of a sensor, in particular a lambda sensor, on which the fluid in the fluid guide acts. The analysis takes place during cranking of the internal combustion engine, and the fluid acting on the sensor is not influenced by fuel that is supplied in a controlled manner.