Systems and methods for improving operation of a vehicle are presented. In one example, a controller may respond to a temperature of a catalyst to permit or temporarily inhibit a vehicle from moving. Engine load and engine emissions may be reduced by limiting vehicle motion until a catalyst temperature exceeds a threshold temperature.

A management device 100 includes: a data acquisition unit 122 configured to acquire cumulative data for each parameter related to stress acting on a DOC 33 configured to purify exhaust gas of an engine and an exhaust gas temperature of the exhaust gas raised for purification; a damage degree identification unit 123 configured to identify a degree of damage to the DOC 33 based on the acquired cumulative data; a relationship identification unit 124 configured to identify a relational expression indicating a relationship between the identified degree of damage and the exhaust gas temperature; an target information acquisition unit 125 configured to acquire an exhaust gas temperature of exhaust gas raised for purification performed by the DOC 33; and a diagnosis unit 126 configured to estimate a degree of damage to the DOC 33 based on the acquired exhaust gas temperature and the identified relational expression.

A control device and a control method for a multi-cylinder internal combustion engine including a post-processing device are provided. The control device includes an electronic control unit executing a temperature raising process of raising the temperature of the post-processing device and a recovery-time process. The temperature raising process includes a stopping process and a rich process. In the stopping process, supply of fuel to several of cylinders is stopped. In the rich process, the air-fuel ratio of an air-fuel mixture for different ones of the cylinders other than the several cylinders is made lower than the stoichiometric air-fuel ratio. In the recovery-time process, the concentration of unburned fuel in exhaust gas discharged to the exhaust passage is made higher than an equivalent concentration, when the temperature raising process is stopped. The equivalent concentration is the concentration of unburned fuel being just enough to react with oxygen in the exhaust gas.

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.

In the exhaust gas control system, the electronic control unit is configured to execute first air-fuel ratio control for controlling an air-fuel ratio of an air-fuel mixture in a part of cylinders to a lean air-fuel ratio and controlling an air-fuel ratio of an air-fuel mixture in the other part of the cylinders to a rich air-fuel ratio is executed. The electronic control unit is configured to execute second air-fuel ratio control to perform malfunction diagnosis. The electronic control unit is configured to execute second air-fuel ratio control when the execution of the first air-fuel ratio control is interrupted after the temperature of the three-way catalyst becomes equal to or higher than the diagnosis temperature.

In an internal combustion engine that includes: an EGR channel that connects a portion of an exhaust channel on the upstream side of a downstream-side catalyst and a portion of an intake channel on the downstream side of both of a compressor and a throttle valve; and an EGR valve configured to open and close the EGR channel, a control apparatus is programmed, where an occurrence of a blow-through air that flows from the intake channel to the exhaust channel via the EGR channel is detected, to limit a throttle downstream pressure to reduce the overheating of the downstream-side catalyst.

An internal combustion engine (ICE) and method of control are provided to determine a value of a catalyst temperature and a value of a quantity of a reducing agent stored in the catalyst. The quantity of gas recirculated by an exhaust gas recirculation (EGR) system of the ICE is calculated on the basis of the value of the catalyst temperature and of the value of the quantity of the reducing agent stored in the catalyst. This solution makes it possible to adjust the quantity of gas recirculated by the EGR system on the basis of parameters linked to an efficiency of a selective catalytic reduction (SCR) system associated with the ICE, in order to reduce the global quantity of pollutants produced by the ICE and released in the environment.

Methods and systems are provided for an exhaust system. In one example, the exhaust system includes an aftertreatment device and a recirculation passage. A recirculation valve is positioned in the recirculation passage and configured to control an amount of recirculated exhaust gas flowing through the recirculation passage to the aftertreatment device. The exhaust system further includes a diverter valve configured to control a flow of engine exhaust gases to different portions of a catalyst of the aftertreatment device.

Methods and systems are provided for improving the performance of a variable displacement engine. Split injection and spark retard may be used in active cylinder during a VDE mode to heat an exhaust catalyst and extend the duration of VDE mode operation. Split injection and spark retard may also be used in reactivated cylinders at a time of cylinder reactivation to improve restart combustion stability.

A skip fire engine controller and method of control is described wherein during transitions from a first firing density to a second firing density, a firing density and a pumping density are separately set so as to balance the conflicting demands of (a) torque control, (b) Noise, Vibration and Harshness (NVH), (c) air flow through the engine and (d) air-fuel ratio.