Methods and systems are provided for adjusting a substitution ratio based on water in a combustion mixture of a multi-fuel engine. In one example, a method includes adjusting a substitution ratio in response to an amount of water provided to a multi-fuel engine configured to combust a first fuel and a second fuel, the second fuel different than the first fuel.

A method for operating an exhaust gas sensor in an exhaust system of an internal combustion engine of a vehicle. The exhaust gas sensor includes a ceramic sensor element having at least one measuring electrode and a heating device. A binary dewpoint end signal is calculated, based on data which relate to the internal combustion engine and the exhaust gas sensor, which indicates whether or not the occurrence of liquid water in the exhaust system is still to be expected. Whenever the vehicle is turned off and the dewpoint end signal simultaneously has the value which signals that the occurrence of liquid water in the exhaust system is still to be expected, the sensor element is heated by its heating device to a temperature for a certain period of time in such a way that the sensor element dries.

The invention relates to a method for operating an internal combustion engine comprising: determining a first set point value of a volume of air to be taken into the combustion chamber of the internal combustion engine within one working cycle thereof by retrieving the first set point value from a first characteristic map stored in a memory device of an electronic computing device as a function of a current engine speed of the internal combustion engine and as a function of a torque to be provided by the internal combustion engine; and determining a second set point value by retrieving the second set point value from a second characteristic map stored in the memory device of the electronic computing device as a function of a current engine speed of the internal combustion engine and as a function of a current volume of air supplied to the combustion chamber.

The present disclosure provides a method for controlling EGR rate of a low pressure EGR system, a system and a vehicle. The method calculates a molar concentration of water molecules of exhaust gas processed by EGR cooler, calculates a molar concentration of water molecules, obtains coefficient as to excess air, and calculates a molar volume ratio of air according to the coefficient. Under a maximum limit of humidity, an allowable EGR rate of the exhaust gas processed by the EGR cooler is determined and an allowable EGR rate of the mixed gas before entry into supercharger and/or compressor is also determined, a lower EGR rate between the two allowable rates is set as a maximum for application actual working conditions. The present disclosure solves a problem of condensation caused by an introduction of exhaust gas from the existing gasoline engine.

A control device of an exhaust sensor comprises a heater control part configured to set a target temperature of an electrochemical cell and control a heater so that a temperature of the electrochemical cell becomes the target temperature, and a judging part configured to judge whether a water repellency of a protective layer is falling when the heater control part sets the target temperature to a temperature of a lowest temperature at which a Leidenfrost phenomenon occurs at an outer surface of the protective layer or more. The heater control part is configured to rise the target temperature when the judging part judges that the water repellency of the protective layer is falling.

Methods and systems are provided for adjusting the amount of secondary fluid being injected into an engine. In one example, a method may include adjusting an amount of secondary fluid injected at an engine cylinder based on a secondary fluid injection amount estimated from outputs of an exhaust oxygen sensor. For example, the secondary fluid injection amount may be estimated based on a first change in pumping current of the exhaust oxygen sensor between a first and second reference voltage when only fuel is injected into the engine cylinder and a second change in pumping current of the exhaust oxygen sensor between the first and second reference voltage when fuel and the secondary fluid are injected into the engine cylinder.

Embodiments for diagnosing a humidity sensor are provided. One example method comprises, responsive to a humidity sensor test cycle, pumping air conditioning and windshield washer gas flows past a humidity sensor, and indicating humidity sensor degradation based on a response of the humidity sensor to the air conditioning and windshield washer gas flows. In this way, degradation of the humidity sensor may be indicated if the humidity sensed by the humidity sensor does not change responsive to the humidity sensor test cycle being initiated.

Methods and systems are provided for estimating a PCV flow to an engine based on the output of an exhaust gas oxygen sensor. During DFSO conditions, a reference voltage of the sensor is modulated initially with an intake throttle open and then with the intake throttle closed. PCV flow leaking past the piston valves in an aging engine, as well as an ambient humidity estimate, are inferred based on the outputs of the sensor during the modulating with the intake throttle open and closed.

A method comprising adjusting a fuel injection amount based on a fractional oxidation state of a catalyst, the fractional oxidation state based on reaction rates of grouped oxidant and reductant exhaust gas species throughout a catalyst and a low-dimensional physics-based model derived from a detailed two-dimensional model to obtain a one-dimensional model averaged over time and space that accounts for diffusion limitations in the washcoat and accurately predicts emissions during cold start.

The condensed water treatment device increases the EGR quantity (S16, S17) so as to be larger than the EGR quantity (Qe) calculated based on the operating state, when within a specific time period (S13) from a moment when execution of filter regeneration control is started to a moment after predetermined time has elapsed following the end of the execution, and also in a case where (S15) the storage water quantity (Qw) of a condensed water tank storing condensed water generated in an EGR cooler is smaller than a normative water quantity (Qwt).