A dual fuel system includes a liquid pilot fuel supply, a liquid main fuel supply, and a fuel injection apparatus. The dual fuel system further includes a fueling control unit coupled with a cylinder pressure sensor and a NOx sensor, and structured to vary, via outputting a fueling control command to a main fuel injection control valve, fuel delivery parameters each on the basis of at least one of a cylinder pressure parameter or a NOx parameter. The fueling control unit compensates via the varying fuel delivery parameters for a change to a liquid main fuel composition such as a change from a first alcohol fuel or blend to a second alcohol fuel or blend.

A system includes an aftertreatment system heater of an exhaust aftertreatment system coupled to an engine A controller coupled to the aftertreatment system heater is configured to determine a condition of an exhaust gas from an engine and compare the condition to a predefined threshold. If the condition of the exhaust gas does not meet the predefined threshold, the controller is configured to determine whether an engine operating condition is met for activating a cylinder deactivation operating mode for the engine. If the engine operating condition is met, the controller is configured to operate the engine in the cylinder deactivation operating mode by deactivating a cylinder of a plurality of cylinders. If the engine operating condition is not met, the controller is configured to activate the aftertreatment system heater to heat the exhaust gas.

A system and approach for catalyst model parameter identification with modeling accomplished by an identification procedure that may incorporate a catalyst parameter identification procedure which may include determination of parameters for a catalyst device, specification of values for parameters and component level identification. Component level identification may be of a thermal model, adsorption and desorption, and chemistry. There may then be system level identification to get a final estimate of catalyst parameters.

A three-way catalyst and an NO.sub.x adsorption catalyst are disposed in an engine exhaust passage. In a predetermined low-load engine operation area, combustion in a combustion chamber is carried out at a lean base air-fuel ratio and an air-fuel ratio in the combustion chamber is changed to a rich range at the time of discharging NO.sub.x from the NO.sub.x adsorption catalyst. In a predetermined high-load engine operation area, the air-fuel ratio in the combustion chamber is controlled to a theoretical air-fuel ratio in a feedback manner. In a predetermined middle-load engine operation area, the combustion in the combustion chamber is carried out at the base air-fuel ratio lower than the base air-fuel ratio in the low-load engine operation area and the air-fuel ratio in the combustion chamber is changed to the rich range with a period shorter than a rich period of the air-fuel ratio for discharging NO.sub.x in the low-load engine operation area.

This disclosure provides a system and method for controlling internal combustion engine system to reduce operation variations among plural engines. The system and method utilizes single-input-single-output (SISO) control in which a single operating parameter lever is selected from among exhaust gas recirculation (EGR) fraction and charge air mass flow (MCF), and a stored reference value associated with the selected lever is adjusted for an operating point in accordance with a difference between a measured emissions characteristic and a pre-calibrated reference value of the emissions characteristic for that operating point. Adjusting the selected operating parameter lever towards the theoretical pre-calibrated reference value of the operating parameter lever for each of plural operating points can reduce engine-to-engine variations in engine out emissions.

A system and method of integrating an engine having dynamic skip fire control with an exhaust gas recirculation system in a turbocharged internal combustion engine is described. An engine control system determines an appropriate firing pattern based at least in part on a desired exhaust gas recirculation flow rate. Signals from sensors in the intake manifold and exhaust system may also be used as part of a feedback loop to determine a desired exhaust gas recirculation flow rate.

A method for operating an internal combustion engine having a motor and an exhaust gas aftertreatment system having an exhaust gas aftertreatment component, wherein exhaust gas formed in the motor during combustion of fuel is guided via the exhaust gas aftertreatment system for cleaning, includes: determining an exhaust gas actual value that depends upon an actual value of a nitrogen dioxide fraction in the exhaust gas upstream of the exhaust gas aftertreatment component; and changing at least one operating parameter for the motor such that the actual value of the nitrogen dioxide fraction is brought closer to a corresponding reference value for the nitrogen dioxide fraction.

A gas engine heat pump and a method of operating the same are provided. According to an embodiment of the present disclosure, the gas engine heat pump includes: an engine for burning a mixture of air and fuel; an exhaust gas compressor for compressing exhaust gases coming from the engine; a buffer tank for storing the exhaust gases compressed by the exhaust gas compressor; an exhaust gas valve disposed between the buffer tank and an intake manifold of the engine; an exhaust gas spray nozzle for spraying the exhaust gases stored in the buffer tank into a cylinder of the engine; an exhaust gas sensor for acquiring information on the exhaust gases coming from the engine; and a controller, wherein the controller controls the operation of at least one of the exhaust gas valve and the exhaust gas spray nozzle, based on the information on the exhaust gases acquired by the exhaust gas sensor. Other various embodiments are possible.

The present disclosure relates to a gas engine heat pump including: an engine which burns a mixed air of air and fuel; a first charger which compresses the mixed air and supplies to the engine; a first exhaust flow path which is connected to the engine, and through which exhaust gas discharged from the engine flows; and a second charger which is driven by the exhaust gas branched from the first exhaust flow path to a second exhaust flow path, and compresses the exhaust gas discharged from the engine and supplies the compressed exhaust gas to the engine, thereby reducing the emission of nitrogen oxide by recirculating the exhaust gas without additional power consumption.

Various methods and systems are provided for controlling emissions. In one example, a controller is configured to respond to a sensed exhaust oxygen concentration by changing a fuel injection timing to maintain particulate matter (PM) within a range, and then adjusting an exhaust gas recirculation (EGR) amount based on NOx sensor output and based on the change in fuel injection timing.