A control system includes a supercharged engine and an electronic control unit. The supercharged engine including: a combustion chamber; an exhaust passage; a turbine; and an exhaust catalyst. The turbine includes a turbine wheel, and a turbine control valve. The electronic control unit is configured to calculate a first exhaust gas temperature and a second exhaust gas temperature that are temperatures of exhaust gas flowing into the exhaust catalyst. The electronic control unit is configured to control the turbine control valve such that: the turbine control valve is set to the first valve opening degree when the first exhaust gas temperature is higher than the second exhaust gas temperature; and that the turbine control valve is set to the second valve opening degree when the second exhaust gas temperature is higher than the first exhaust gas temperature.

Methods and systems for operating an engine with an electrically driven compressor are described. In one example, output of the electrically driven compressor is adjusted to increase a temperature of an engine so that the engine may be started without glow plugs or with glow plugs that have a lower heat capacity output. Additionally, a position of a recirculation valve may be adjusted to increase the temperature of the engine.

A control apparatus of an engine including an intake valve, an exhaust valve, and a variable valve timing mechanism for varying open and close timings of at least one of the intake and exhaust valves, is provided. The control apparatus includes a processor configured to execute a valve controlling module for performing, via the variable valve timing mechanism, a valve overlap in which the intake and exhaust valves are both opened on intake stroke of the engine, and a temperature estimating module for estimating a temperature of exhaust gas at a given location in the exhaust system by estimating a temperature increase of the exhaust gas caused by afterburn and accounting for the temperature increase, the afterburn occurring due to fresh air blowing through a cylinder of the engine to an exhaust system during the valve overlap.

A control apparatus for an internal combustion engine configured to perform control to remove a combustible residue adhered to an exhaust path of the internal combustion engine includes one or more processors and one or more memories communicatively coupled to the one or more processors. The one or more processors are configured to: obtain information on an exhaust temperature at a predetermined position in the exhaust path during operation of the internal combustion engine; determine whether the exhaust temperature or a predetermined reference temperature obtained based on the exhaust temperature has exceeded a threshold; and, when the exhaust temperature or the reference temperature has exceeded the threshold, increase an amount of oxygen to be supplied to the exhaust path to forcibly combust the combustible residue.

Methods and systems are provided for accurately inferring an exhaust temperature during steady-state and transient vehicle operation based on the duty cycle of an exhaust gas sensor heating element. A steady-state temperature is inferred based on an inverse of the duty cycle, and then adjusted with a transfer function that compensates for transients resulting from changes in vehicle speed, and load, and for the occurrence of tip-in and tip-out events. The inferred temperature can also be compared to a modeled temperature to identify exhaust temperature overheating conditions, so that mitigating actions can be promptly performed.

An air flowmeter is arranged in an intake passage. An air-fuel ratio sensor is arranged downstream of an addition valve in an exhaust passage. An estimated air-fuel ratio is calculated based on an intake air amount detected by the air flowmeter and the sum of a fuel amount injected by a fuel injection valve and a fuel amount added by the addition valve. It is determined that there is a stuck-closed anomaly in the addition valve if the logical conjunction is true of a condition that a detected value of the air-fuel ratio sensor is greater than the estimated air-fuel ratio by a margin greater than or equal to a specified amount and a condition that a detected value of the exhaust temperature sensor in a period in which the addition valve adds fuel is smaller than a reference value in the period by a margin greater than or equal to a predetermined amount.

An air flowmeter is arranged in an intake passage. An air-fuel ratio sensor is arranged downstream of an addition valve in an exhaust passage. An exhaust temperature sensor is arranged downstream of a catalyst. An air amount estimating process calculates an estimated air amount based on the air-fuel ratio detected by the air-fuel ratio sensor and the fuel amount injected by a fuel injection valve. An upward displacement anomaly determining process determines that there is an anomaly in which a detected value of the air flowmeter is greater than an actual value if a logical conjunction is true of the condition that the detected value of the air flowmeter is greater than the estimated air amount by a margin greater than or equal to a specified amount and the condition that an amount by which a detected value of the exhaust temperature sensor exceeds a reference value is smaller than or equal to a predetermined amount.

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.

An estimation device includes: a memory and a processor, wherein the processor is configured to execute a process including: determining a point of a burning having a higher peak in a predetermined range of a heat release rate based on a peak of a burning having a smaller peak, in a heat release rate waveform in an internal combustion engine that performs a multiple-stage fuel injection; calculating a tangential line of the heat release rate waveform at the point; setting a predetermined point on the tangential line as an initial value for identifying a model parameter of a heat release rate model; identifying the model parameter so that a difference between a calculation value of the heat release rate model and the heat release rate waveform is reduced with use of the initial value; and estimating a heat release rate with a result of an identification of the identifying.

In a method for avoiding a runaway condition of an internal combustion engine that includes a cylinder, an operational characteristic of the engine, presumed to be caused by an unrequested introduction of hydrocarbon into the cylinder, is detected and the engine is derated in dependence of the detection, and, while the engine is derated, a test procedure is performed to detect an unrequested introduction of hydrocarbon into the cylinder.