A method for operating an exhaust gas burner that is situated in an exhaust gas system downstream from an internal combustion engine of a motor vehicle during a start phase of the exhaust gas burner, in which the internal combustion engine is not fired. The method includes an incremental increasing of the air mass flow supplied to the exhaust gas burner and an incremental varying of a fuel mass flow supplied to the exhaust gas burner.

The present invention is applied to an exhaust system provided with a three-way catalyst and a NOx catalyst which are provided in an exhaust passage of an engine and to which sulfur components in exhaust adhere and release the attached sulfur components by rich components in exhaust, and NOx sensors provided downstream of the catalysts. The NOx sensor is a limiting current type sensor. It is determined whether a sulfur release state is present in which a sulfur component is released from the three-way catalyst and the NOx catalyst. When it is determined that it is in the state of sulfur release, reaction suppression processing for suppressing the reaction between oxygen and sulfur components in the pump cell electrodes and the monitor cell electrodes of the NOx sensors is performed.

Systems and methods for controlling a regeneration process of catalyst(s) are disclosed. The method includes receiving, via Kalman filter, initial estimation from a previous instance of time. The initial estimation includes one or more first estimated inside temperature(s) and/or first estimated outlet temperature of A/T catalyst. An output from a simulation model may be generated to calculate a mean and covariance. Sensor measurement covariance may be compared against the mean and covariance of the output to update Kalman filter gain and process covariance. A weighted average may be calculated between sensor measurements and mean of the output to generate a second estimation for the next instance of time, wherein weight is based on Kalman filter gain. The second estimation includes one or more second estimated inside temperature(s) and/or second estimated outlet temperature of A/T catalyst to control the mass flow rate in diesel engine via a closed loop control system.

A control device for an internal combustion engine including an upstream cleaning device and a downstream cleaning device that are provided in an exhaust gas passage and a temperature sensor that detects a temperature of exhaust gas between the upstream cleaning device and the downstream cleaning device is provided. The control device includes a first temperature estimating unit configured to estimate a temperature of the downstream cleaning device from the temperature of exhaust gas detected by the temperature sensor and a second temperature estimating unit configured to estimate a temperature of the downstream cleaning device without using the temperature of exhaust gas detected by the temperature sensor. An abnormality determining process for the upstream cleaning device is performed when at least the temperature of the downstream cleaning device estimated by the second temperature estimating unit is equal to or greater than a predetermined threshold value.

A controller for an internal combustion engine is configured to execute a rich air-fuel ratio control for performing fuel injection while setting a target equivalence ratio such that, at recovery from a fuel cutoff process, an air-fuel ratio of air-fuel mixture is richer than a stoichiometric air-fuel ratio. The controller is configured to execute a target equivalence ratio setting process for setting the target equivalence ratio that is maintained during execution of the rich air-fuel ratio control such that the target equivalence ratio increases as an air excess ratio that is calculated from an output value of a second air-fuel ratio sensor at start of the rich air-fuel ratio control increases.

Provided are an exhaust purification device and an exhaust purification method which can achieve improved fuel efficiency. The exhaust purification device (100) is equipped with: a DOC (5) for occluding hydrocarbons in an exhaust gas; a DPF (6) that is provided downstream from the DOC (5) and is for trapping particulate matter in the exhaust gas; and an ECU (10) for determining, in accordance with the amount of occluded hydrocarbons in the DOC (5), a start time for a regeneration process for removing particulate matter accumulated in the DPF (6).

A vehicle exhaust gas purification system and a control method thereof that may effectively remove nitrogen oxides in an exhaust gas even in a cold state, which is the initial stage of an engine starting, is disclosed. A control method of an exhaust gas purification system of a vehicle may include: a step of performing a rich control for controlling a concentration of non-combusted fuel contained in the exhaust gas flowing into the housing to be a rich fuel directly after the starting of the engine; a step of performing a lean control for controlling the concentration of the non-combusted fuel contained in the exhaust gas flowing into the housing to be a lean fuel; a step of determining whether a temperature of the exhaust gas flowing into the housing is a predetermined temperature or more; and a step of performing a normal control for controlling the concentration of the non-combusted fuel contained in the exhaust gas flowing into the housing so that a lean fuel and a rich fuel are periodically repeated with a regular interval.

A method includes operating an engine system including a plurality of cylinders, a plurality of fuel injectors configured to provide fuel the plurality of cylinders, a compression braking system configured to selectably brake at least a first set of the plurality of cylinders, and an exhaust aftertreatment system including at least one catalyst. The method includes determining a condition for brake-fuel operation and, in response to the act of determining, operating the engine in a brake-fuel mode wherein the compression brake is actuated to provide compression braking of the first set of the plurality of cylinders and a second set of the plurality of cylinders receives and combust fuel provided from respective ones of the plurality of fuel injectors.

A catalyst degradation detection apparatus includes an air-fuel ratio detector disposed downstream of a catalyst and configured to detect an air-fuel ratio of exhaust gas flowing out from the catalyst, and an electronic control unit configured to control an air-fuel ratio of inflow exhaust gas flowing into the catalyst and determine whether the catalyst is degraded. The electronic control unit is configured to execute degradation determination control that brings the air-fuel ratio of the inflow exhaust gas to an air-fuel ratio leaner or richer than a stoichiometric air-fuel ratio. The electronic control unit is configured to determine whether precious metal of the catalyst is degraded based on the air-fuel ratio detected by the air-fuel ratio detector when an oxygen storage amount of the catalyst is varying in the degradation determination control.

When an amount of particulate matter (PM) collected by a gasoline particulate filter (GPF) reaches a predetermined amount, a central processing unit (CPU) executes a regeneration process for regenerating the GPF. That is, the CPU stops supply of fuel to any one of cylinders #1 to #4, while increasing an amount of fuel supplied to remaining cylinders. When a temperature of a three-way catalyst becomes equal to or higher than a first temperature, the CPU increases an injection amount to lower a temperature of exhaust gas. When the temperature of the three-way catalyst becomes equal to or higher than the first temperature during the execution of the regeneration process, the CPU does not increase the injection amount.