Methods and systems are provided for adjusting a throttle during deceleration fuel shut off (DFSO). In one example, a method may comprise controlling a position of a throttle in an air inlet of an engine propelling a vehicle, in relation to vehicle operator commands, and during a deceleration fuel shut off mode, increasing opening of said throttle independently of said operator commands when speed of said vehicle is or is expected to fall below a desired speed or desired speed trajectory.

The disclosure relates to internal combustion engines in general, and teaches various methods and apparatus for operating engines with an exhaust-gas turbocharger. Some embodiments include a method for operating an internal combustion engine having a fresh-gas tract for the supply of fresh gas to a cylinder, and an exhaust tract for the discharge of exhaust gas. They may include determining a value of a first operating condition of a catalytic converter arranged in the exhaust tract; determining a value of a second operating condition of the catalytic converter; calculating, as a function of the determined value, a first value for a maximum admissible scavenged-over quantity of fresh gas into the exhaust tract during scavenging operation; and setting the maximum admissible scavenged-over quantity to a second value lower than the first value if the value of the second operating condition reaches a predefined value.

A system including a DFCO module. The DFCO module is configured to operate in a DFCO mode to deactivate fuel to a cylinder of an engine. A first flow rate module is configured to determine a reaction gas flow rate. An offset module is configured to determine a temperature offset value based on the reaction gas flow rate. A first temperature module is configured to estimate a first temperature of a catalyst of an exhaust system of the engine. A summer is configured to sum the temperature offset value and the first temperature to generate a summation value. A second temperature module configured to estimate a second temperature of the catalyst based on the summation value. A comparison module is configured to perform a first comparison between the second temperature and a threshold and generate an inhibit signal to inhibit operation in the DFCO mode based on the first comparison.

An intake and exhaust system includes an engine, an exhaust flow passage, a catalyst, and a control apparatus. The exhaust flow passage is coupled to the engine. The catalyst is disposed in the exhaust flow passage and configured to purify exhaust gas. The control apparatus includes one or more processors, and one or more memories coupled to the one or more processors. The one or more processors are configured to: before the engine is started up, execute scavenging control that causes the exhaust gas remaining in the engine and the exhaust flow passage to flow to pass through the catalyst before being discharged; and before the engine is started up, execute warming control that warms up the catalyst, based on a degree of purification of the exhaust gas by the catalyst during execution of the scavenging control.

Provided is a powertrain control device for a vehicle including an exhaust gas purification apparatus and an automatic transmission, the vehicle traveling by controlling an engine and the automatic transmission. The powertrain control device includes an engine control module (ECM) and a transmission control module (TCM). The ECM performs entire-range stoichiometric air-fuel ratio operation control, and also performs intake air charge amount limit control when an intake air charge amount reaches an upper limit value that is set to prevent a temperature of a three-way catalyst from exceeding an allowable temperature. The TCM performs automatic shift control, and performs forced upshift control of forcibly shifting up the automatic transmission when an engine revolution speed reaches a revolution limit. When the ECM limits the intake air charge amount, the TCM performs revolution limit change control of lowering the revolution limit.

When an accelerator opening degree is lower than a predetermined accelerator determination opening degree, a control device implements a fuel cut that stops fuel supply by an injector; when the control device implements the fuel cut, the control device implements an intake air amount increase control that controls an intake air amount adjustment device when a catalyst temperature is high so that an intake air amount is larger than when the catalyst temperature is low; when the control device ends the fuel cut and resumes fuel supply by the injector, the control device implements a fuel amount increase control that controls the injector so that a fuel amount to be supplied to a combustion chamber is larger than a basic fuel amount; and the control device prohibits the intake air amount increase control for a predetermined period after the control device ends the fuel amount increase control.

When an accelerator opening degree is equal to or less than a predetermined accelerator determination opening degree, a control device implements a fuel cut that stops fuel injection by an injector; and when the fuel cut is implemented while a catalyst temperature is equal to or higher than a predetermined determination temperature, the control device implements an intake air amount increase control that controls an intake air amount adjustment device so that an intake air amount is larger than while the catalyst temperature is lower than the determination temperature, and the control device controls the intake air amount adjustment device so that an increase rate of the intake air amount is decreased as the catalyst temperature increases.

There is provided an engine power generation system control device that reduces emission of a harmful substance contained in an exhaust gas to the outside by performing prompt activation of an exhaust purification catalyst and prompt warmed-up of an engine in a power generation system including an engine enabling an RE fuel and a hydrocarbon-based fuel to be supplied and performing co-combustion. A hydrocarbon-based fuel supply amount or a hydrogen supply amount to the engine is controlled based on a catalyst active state detected by a catalyst active state detecting unit and a warmed-up state of the engine detected by an engine warmed-up state detecting unit.

A control signal is issued to a turbo shaft actuator to rotate a turbine at a first turbine speed in response to an ignition turn on signal. The first turbine speed is different from a default turbine speed. The rotation of the turbine at the default turbine speed results in exhaust gas having a first exhaust gas temperature after the exhaust gas passes through the turbine to a catalyst brick of the vehicle. The rotation of the turbine at the first turbine speed results in the exhaust gas having a second exhaust gas temperature after the exhaust gas passes through the turbine to the catalyst brick. The second exhaust gas temperature is higher than the first exhaust gas temperature. When the catalyst temperature is greater than a catalyst light-off temperature a control signal is issued to the turbo shaft actuator to rotate the turbine at the default speed.