Systems and methods of preventing thermal spikes at a catalyst in an exhaust system of an engine of a vehicle include detecting whether one of a fuel enrichment event and a fuel cutoff event has been initiated and in response, temporarily disabling the other of the fuel enrichment event and the fuel cutoff event from occurring to prevent an exhaust gas temperature thermal spike that could damage the catalyst, while the other of the fuel enrichment event and the fuel cutoff event is disabled, performing stoichiometric closed-loop fuel control using the one or more oxygen sensors to drive the exhaust gas fuel/air ratio to stoichiometry and an oxygen storage capacity of the catalyst to a balanced state, and when measurements from the one or more oxygen sensors indicate at least one lean-to-rich transition and one rich-to-lean transition in the exhaust gas oxygen level has occurred, re-enabling the other event.

A method for regulating a filling of an exhaust gas component reservoir of a catalytic converter in the exhaust of an internal combustion engine. An actual fill level of the exhaust gas component reservoir is ascertained using a first system model, and in which a baseline lambda setpoint for a first control loop is predefined by a second control loop in which an initial value for the baseline lambda setpoint is converted, by a second system model identical to the first system model, into a fictitious fill level; the fictitious fill level is compared with a setpoint for the fill level; and the baseline lambda setpoint is iteratively modified as a function of the comparison result. At the beginning of a coasting phase, the baseline lambda setpoint is calculated based on signals of sensors and control variables which relate to the delivery of air and/or fuel to combustion chambers.

Sensing combustion events using a resistive based oxygen sensor exposed to exhaust gases of a periodic combustion process in a combustion engine. The oxygen sensor is disposed in the exhaust plenum of the engine and includes a metal oxide semiconductor layer bridging a gap between first and second electrodes. Spikes in the resistance of the metal oxide semiconductor layer, caused by its reaction to transient changes in the oxygen level and exhaust temperature, are indicated in a combustion signal. The combustion signal may be used to monitor for combustion misfire event(s). Further, a combustion misfire event may be detected by comparing the detected spike timing with expected spike timing, with a spike not being present at a time when a spike is expected indicating a combustion misfire event. Related devices and systems are also disclosed.

A system includes a heating element, a signal injector, and a signal receiver. The heating element is coupled between a first node and a second node. The signal injector is communicatively coupled the heating element via the first node. The signal generator is configured to provide a test signal to the heating element. The signal receiver is communicatively coupled to the heating element via the second node. The signal receiver is configured to receive the test signal from the heating element and to determine a capacitance of the heating element based upon the received test signal.

A method is provided for controlling an engine exhaust with an upstream sensor and a downstream sensor. The method comprises adjusting a set-point for the downstream sensor based on a rate of change of air mass flow upstream of the engine and adjusting fuel injection to control exhaust fuel-air ratio (FAR) at the downstream sensor to the adjusted set-point, and to control exhaust FAR at the upstream sensor to an upstream sensor set-point.

An exhaust gas recirculation (EGR) control method includes a valve duty differentiated control including: detecting, by a controller, an engine operation region, a mixer region, and an external factor region as a valve control condition for an EGR valve duty correction variable for controlling an EGR system; applying, by the controller, the EGR valve duty correction variable to an EGR valve duty, which is set by a target air amount to an intake air amount, to calculate a minimum EGR valve duty; and outputting, by the controller, the calculated minimum EGR valve duty to an EGR valve as the EGR valve duty.

Method and apparatus for monitoring and/or detecting combustion misfire events in periodic combustion processes in internal combustion engines, using combustion signals derived from a first oxygen sensor exposed to exhaust gas of a periodic combustion process and a second oxygen sensor exposed to the same exhaust gas. The first oxygen sensor is resistive-based, and responds relatively faster to changes in the temperature and/or composition of the exhaust gas. The second oxygen sensor is voltaic-based or ampometric-based, and responds relatively slower to changes to the temperature and/or composition of the exhaust gas. When the temperature and/or composition of the exhaust changes rapidly but transiently due to a combustion misfire event, the different response rates of the first and second combustion signals allows for the combustion misfire event(s) to be detected. Either and/or both oxygen sensors may be used to control the engine in a conventional fashion.

A method is described for regulating a filling of an exhaust gas component storage of a catalytic converter in the exhaust gas of an internal combustion engine, in which an actual fill level of the exhaust gas component storage is ascertained using a first system model, and in which a base lambda setpoint value for a first control loop is predefined by a second control loop. The method is distinguished by the fact that in the second control loop an initial value for the base lambda setpoint value is converted into a fictitious fill level via a system model identical to the first system model, the fictitious fill level being compared with a setpoint value for the fill level output by a setpoint value generator, and the base lambda setpoint value being iteratively changed as a function of the comparison result, if the comparison result indicates a difference between the setpoint value for the fill level and the fictitious fill level, which is greater than a predefined degree, and the base lambda setpoint value not being changed if the comparison result indicates no difference between the setpoint value for the fill level and the fictitious fill level.

Methods and systems are provided for adjusting a voltage of a heated oxygen sensor (HEGO) so that the heated oxygen sensor is controlled to a desired temperature as the HEGO ages. In one example, a method generates a requested heated oxygen sensor electrode impedance for control and then adjusts the voltage responsive to the requested heated oxygen sensor electrode impedance for control.

Methods and systems are provided for adjusting a voltage of a heated oxygen sensor (HEGO) so that the heated oxygen sensor is controlled to a desired temperature as the HEGO ages. In one example, a method generates a requested heated oxygen sensor electrode impedance for control and then adjusts the voltage responsive to the requested heated oxygen sensor electrode impedance for control.