Proposed is a gas heat-pump system capable of supplying recirculation exhaust gas using a motor-driven turbocharger and thus actively controlling an amount of flowing recirculation exhaust gas and pressure thereof.

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.

An apparatus includes an engine module, an in-cylinder content module, and an engine out NOx module. The engine module is structured to interpret engine in-cylinder data regarding an operating condition within a cylinder of an engine, wherein the engine in-cylinder data includes an engine torque, an engine speed, a rail pressure, and a start-of-injection. The in-cylinder content module is structured to interpret at least one additional in-cylinder data point regarding the operating condition within the cylinder of the engine. The engine out NOx module is structured to determine an engine out NOx amount responsive to the engine in-cylinder data and the at least one additional in-cylinder data point.

A method for operating an internal combustion engine of a motor vehicle, which has an exhaust gas system that exhaust gas from at least one combustion chamber of the internal combustion chamber can flow through and includes at least one nitrogen oxide storage catalyst, at least one particulate filter, and at least one selective catalytic reduction (SCR) catalyst.

An exhaust gas after-treatment system for an internal combustion engine includes a selective catalyst reduction on filter (SCRF) exhaust gas after-treatment device in communication with exhaust gases from the internal combustion engine and having treated exhaust gas output. An oxides of nitrogen (NOx) sensor is coupled to treated exhaust gases and has a NOx sensor output signal that is NOx and ammonia (NH.sub.3) cross-sensitive. A closed loop observer (CLO) is operatively coupled to receive the NOx sensor output signal and provides a NOx concentration signal to an electronic control unit operatively associated with the exhaust gas after-treatment system and the internal combustion engine. CLO output at least includes an exhaust gas NOx concentration estimate and the ECU is arranged to be operable upon the NOx concentration estimate to control exhaust gas after-treatment system and internal combustion engine to effect an overall reduction in actual NOx concentration with the exhaust gases.

An engine control device is provided, which includes an engine body where a cylinder is formed, an exhaust passage through which exhaust gas discharged from the engine body circulates, a NO.sub.x sensor disposed in the exhaust passage and configured to detect a concentration of NO.sub.x in the exhaust gas, an injector configured to change an air-fuel ratio inside the cylinder, an in-cylinder temperature changer configured to change a temperature inside the cylinder, and a controller configured to control the injector and the exhaust shutter valve. The controller controls the injector based on a detection value of the NO.sub.x sensor to variably set the air-fuel ratio inside the cylinder, and when a particular condition that the air-fuel ratio inside the cylinder is leaner than a preset upper limit is satisfied, and causes the in-cylinder temperature changer to raise the temperature inside the cylinder.

Diagnostics for inadequate performance and/or degradation of an exhaust aftertreatment system are disclosed. A performance degradation analysis of the exhaust aftertreatment system includes a determination of a long term brake specific NOx value over a time period and a comparison of the long term brake specific NOx value to a threshold value.

A method for operating a nitrogen oxide sensor of a vehicle having a first nitrogen oxide sensor, a second nitrogen oxide sensor and a catalytic converter, one of the first and second nitrogen oxide sensors being arranged upstream of the catalytic converter with respect to the exhaust gas flow direction, and the other of the first and second nitrogen oxide sensors being arranged downstream of the catalytic converter, includes: determining a first characteristic value of the first nitrogen oxide sensor; determining a second characteristic value of the second nitrogen oxide sensor determining a ratio of the first characteristic value to the second characteristic value; and adapting a sensor or measured value of the second nitrogen oxide sensor in accordance with the ratio of the first characteristic value to the second characteristic value.

A method for operating an internal combustion engine, involving the following steps: determining a target lambda value and measuring an actual lambda value for combustion in a combustion chamber of an internal combustion engine; establishing, in accordance with the target lambda value and the actual lambda value, a point in time for an intake valve associated with the combustion chamber to open; and opening the intake valve at the established point in time.

An engine includes an air intake system, an exhaust system, a single-cylinder-sourced EGR system, an exhaust sensor that is disposed to monitor exhaust gas from the single one of the cylinders, and a diverter valve. A controller includes an instruction set that executable to determine operation of the engine in a fuel cut-off mode, discontinue fuel flow to the single one of the cylinders, divert exhaust gas from the single one of the cylinders to the air intake system, determine an airflow, temperature, and an equivalence ratio of the diverted exhaust gas from the single one of the cylinders, determine a mass flowrate of oxygen in the diverted exhaust gas, integrate the mass flowrate of oxygen in the diverted exhaust gas, and discontinue the diverting of the exhaust gas from the single one of the cylinders when the integrated mass flowrate of oxygen is greater than a threshold value.