An internal combustion engine-based system includes an internal combustion engine. The internal combustion engine-based system includes an engine interrupt connected to the engine. The engine interrupt is configured to selectively stop the operation of the engine. The internal combustion engine-based system includes a controller in communication with the engine interrupt. The internal combustion engine-based system includes a carbon monoxide detector in communication with the controller. The controller uses the engine interrupt to stop the operation of the engine when the carbon monoxide detector provides the controller with signals that are representative of a carbon monoxide level proximate the internal combustion engine that together form a trend of building carbon monoxide amounts over a set time interval.

A system and method is provided for the use of the ion current signal characteristics for onboard cycle-by-cycle, cylinder-by-cylinder measurement. The system may also control the engine operating parameters based on a predicted NOx emission level, CO emission level, CO.sub.2 emission level, O.sub.2 emission level, unburned hydrocarbon (HC) emission level, cylinder pressure, or a cylinder temperature measurement according to characteristics of the ion current signal.

An internal combustion engine is described, and includes a method for operating that includes determining an observed carbon monoxide (CO) ratio in an exhaust gas feedstream, determining an observed in-cylinder scavenging based upon the observed CO ratio in the exhaust gas feedstream, and controlling, by a controller, control states for the variable cam phasing system to control opening times of engine intake valves in relation to closing times of engine exhaust valves based upon the observed in-cylinder scavenging.

A system for controlling an air/fuel ratio in an engine based on catalyst deactivation includes an NH.sub.3 detector disposed downstream from the three way catalyst, and a subsystem that compares measured values of NH.sub.3 concentration with a nominal value of NH.sub.3 concentration at rich operating conditions. A subsystem adjusts the air/fuel ratio based on the measured value of NH.sub.3 concentration and estimated CO concentration.

A system includes a controller that has a processor. The processor is configured to receive a first signal from a first sensor indicative of a first exhaust measurement, wherein the first sensor is disposed at a catalytic converter system inlet of a catalytic converter system. The processor is further configured to derive one or more of an estimated length, estimated volume, or estimated transport delay of an exhaust conduit based on the first signal, wherein a first end of the exhaust conduit is connected to an engine outlet of a engine, and a second end of the exhaust conduit is connected to the catalytic converter system inlet; and to apply the one or more of estimated length, estimated volume, or estimated transport delay of the exhaust conduit during control of the engine.

An air-fuel ratio control device switches a target air-fuel ratio from a lean set air-fuel ratio to a rich set air-fuel ratio after judging that an air-fuel ratio of an outflowing exhaust gas has become a stoichiometric air-fuel ratio and an oxygen storage amount of an exhaust purification catalyst has become a switching reference storage amount, and makes an average value of the target air-fuel ratio the stoichiometric air-fuel ratio to less than the lean set air-fuel ratio, from after the estimated value of the oxygen storage amount has become the switching reference storage amount or more until judging that the air-fuel ratio of the outflowing exhaust gas has become the stoichiometric air-fuel ratio if the estimated value of the oxygen storage amount becomes the switching reference storage amount or more before judging that the air-fuel ratio of the outflowing exhaust gas has become the stoichiometric air-fuel ratio.

In accordance with example implementations, a vehicle includes a body, an engine within the body, and at least one exhaust tube extending from the engine and having a particulate filter fluidly coupled to the exhaust tube to receive exhaust material from the exhaust tube. The vehicle also has at least one air injection pipe having a first end with an inlet arranged to receive air flow entering the body while the vehicle is moving, wherein the air injection pipe comprises a second end fluidly coupled to the exhaust tube and having an outlet positioned to provide air flow from the injection pipe into the exhaust tube upstream from the particulate filter. Passive soot regeneration with THC and CO reductions is realized by this introduced air flow.

An internal combustion engine-based system includes an internal combustion engine. The internal combustion engine-based system includes an engine interrupt connected to the engine. The engine interrupt is configured to selectively stop the operation of the engine. The internal combustion engine-based system includes a controller in communication with the engine interrupt. The internal combustion engine-based system includes a carbon monoxide detector in communication with the controller. The controller uses the engine interrupt to stop the operation of the engine when the carbon monoxide detector provides the controller with signals that are representative of a carbon monoxide level proximate the internal combustion engine that together form a trend of building carbon monoxide amounts over a set time interval.