According to the invention, a method for air path control of a combustion engine is provided, comprising an EGR valve and a VGT turbine. The method comprises providing a cost function of a measured delta pressure between engine intake and exhaust manifold; determining a gradient of the cost function as a function of a delta pressure set point, determining a gradient of a constraint function for estimated NOx emission level, turbine rate; and oxygen level as a function of delta pressure; real time controlling the NOx emission level and delta pressure to respective desired NOx and delta pressure set points by adjusting the EGR valve and/or the VGT turbine, wherein the delta pressure set point is adjusted according to an integration of a selected gradient direction of the cost function selected from the determined one or more of the gradients, wherein the determined gradients are prioritized in the order of turbine rate, oxygen level and NOx emission level; and wherein NOx emission level and or a turbine rate and or oxygen levels are constrained; and wherein the adjusted delta pressure set point is perturbed in an extremum seeking operation on the cost function.

A heater system for an exhaust system is provided. The heater system includes a heater disposed in an exhaust conduit. The heater includes a plurality of heating elements disposed in the exhaust conduit. A heating control module controls the plurality of heating elements differently according to operating conditions specific to each heating element. In other forms, the heater system for an exhaust system has a plurality of heating zones, instead of a plurality of heating elements. The heating control module controls the plurality of heating zones differently according to operating conditions specific to each heating zone.

A method for diagnosing a plurality of lambda sensors which are arranged upstream of an exhaust gas catalytic converter in a plurality of exhaust gas banks of a multi-flow exhaust gas system of an internal combustion engine. An opposite lambda offset of the lambda sensors is identified (54) when a difference (ΔT) between a measured exhaust gas temperature (T.sub.measure) and a modeled exhaust gas temperature (T.sub.mod) downstream of the exhaust gas catalytic converter overshoots a threshold value (S).

A fluid control system is provided that in one form includes a first flow channel, a second flow channel, a heater disposed in the second flow channel, and a fluid control device disposed upstream from the first and second flow channels. When the heater is turned on, the fluid control device changes a fluid flow rate through at least one of the first flow channel and the second flow channel. In another form, the fluid control system includes a bypass conduit, a heater disposed within the bypass conduit, and a fluid control device disposed near the inlet and outlet of the bypass conduit. In still another form, the fluid control system includes a regeneration device disposed downstream from at least one exhaust aftertreatment system and closes an outlet of the exhaust pipe.

Provided are a novel exhaust pipe temperature estimation device and a sensor heater control apparatus for an exhaust gas sensor using the same that accurately estimates an estimation exhaust pipe temperature when an internal combustion engine is stopped and restarted in response to a change of an environmental condition of the internal combustion engine and controls an operation of a sensor heater based on the estimated estimation exhaust pipe temperature. Thus, at least first correction information Tz based on a change of an exhaust pipe temperature and an elapsed time at stop, second correction information Ty based on a change of an internal combustion engine temperature at the stop of the internal combustion engine, and third correction information Tz based on a change of a cooling degree due to outdoor air during stop from the stop to restart are obtained, an estimation exhaust pipe temperature at the stop is corrected using at least one or more pieces of the correction information at restart of the internal combustion engine to estimate an estimation exhaust pipe temperature at the restart, and an estimation exhaust pipe temperature during an operation of the internal combustion engine thereafter is obtained using the estimation exhaust pipe temperature as an initial value, and further, a heating operation of a sensor heater is started when the estimation exhaust pipe temperature becomes equal to or higher than a predetermined value.

A controller for an engine estimates a temperature of the exhaust gas and controls the engine according to the estimated exhaust temperature. The controller changes the air-fuel ratio to a stoichiometric air-fuel ratio or leaner. The controller calculates the progress of combustion on the basis of signals of sensors, and estimates an exhaust temperature. In the case where the air-fuel ratio is the stoichiometric air-fuel ratio, the controller estimates the exhaust temperature on the basis of the progress of the combustion, the engine temperature, and a first relationship that is at least defined between the progress of the combustion and the exhaust temperature, . In the case where the air-fuel ratio is lean, the controller estimates the exhaust temperature on the basis of the progress of the combustion, the engine temperature, and a second relationship that differs from the first relationship.

A system for estimating engine performance is configured to receive, via a cylinder combustion model, a cylinder pressure of a cylinder associated with operation of an internal combustion engine. The system estimates a liner bending moment based at least in part on the cylinder pressure, generates a piston side load associated with the cylinder based at least in part on the liner bending moment, and estimates a piston friction value for a piston associated with the cylinder. The piston friction value may be based at least in part on the cylinder pressure and an engine speed of the internal combustion engine. The system receives, via a convective heat transfer model, an exhaust heat transfer value indicative of a cumulative heat transfer from an exhaust manifold, and estimates an engine torque value based at least in part on the exhaust heat transfer value.

A method of predicting the temperature of a resistive heating element in a heating system is provided. The method includes obtaining resistance characteristics of resistive heating elements and compensating for variations in the resistance characteristics over a temperature regime. The resistance characteristics of the resistive heating element include, but are not limited to, inaccuracies in resistance measurements due to strain-induced resistance variations, variations in resistance due to the rate of cooling, shifts in power output due to exposure to temperature, resistance to temperature relationships, non-monotonic resistance to temperature relationships, system measurement errors, and combinations of resistance characteristics. The method includes interpreting and calibrating resistance characteristics based on a priori measurements and in situ measurements.

The abnormality diagnosis system 1, 1, 1 of an ammonia detection device 46, 71 comprises: an air-fuel ratio detection device 41, 72 arranged in the exhaust passage 22 at the downstream side of the catalyst 20; an air-fuel ratio control part 51 configured to control an air-fuel ratio of exhaust gas; and an abnormality judgment part 52 configured to judge abnormality of the ammonia detection device. The air-fuel ratio control part performs rich control making the air-fuel ratio of the inflowing exhaust gas richer than a stoichiometric air-fuel ratio. The abnormality judgment part judges that the ammonia detection device is abnormal if, after start of the rich control, an output value of the ammonia detection device does not rise to a reference value before the air-fuel ratio detected by the air-fuel ratio detection device falls to a rich judged air-fuel ratio richer than a stoichiometric air-fuel ratio.

When it is determined that there is a likelihood of occurrence of an abnormality in a supercharger, a maximum engine rotation speed and a maximum MG2 rotation speed are changed to a low rotation speed side and operating points of an engine and a rotary machine are controlled such that an engine rotation speed and an MG2 rotation speed are respectively within ranges which do not exceed the changed maximum rotation speeds. Accordingly, even when the supercharger does not operate normally and an abnormal increase in a supercharging pressure occurs, it is possible to curb a high-rotation state of the engine rotation speed and the MG2 rotation speed. As a result, even when an abnormal increase in the supercharging pressure occurs, it is possible to curb a decrease in durability of components.