A catalyst control system includes a stop and start module that, during a period that the vehicle is ON between (i) a first time when the vehicle is turned ON and (i) a second time when the vehicle is next turned OFF, selectively shuts down and starts a spark ignition engine of the vehicle. A catalyst light off (CLO) control module initiates a first CLO event for a first engine startup during the period and, when a temperature of a catalyst that receives exhaust output by the engine is less than a predetermined temperature, selectively initiates a second CLO event for a second engine startup during the period. A fuel control module richens fueling of the engine during the first and second CLO events of the period. A spark control module retards spark timing of the engine during the first and second CLO events of the period.

A method for operating an internal combustion engine of a drivetrain of a vehicle during launching. The vehicle has an exhaust-gas aftertreatment system for purifying exhaust gas of the engine. After a starting operation of the engine, the drivetrain is operated in a first operating state. In this first operating state, the engine is operated at idle, the exhaust-gas aftertreatment system is heated by the internal combustion engine, and a launch prohibition is active. The launch prohibition that is active in the first operating state prevents launching using the internal combustion engine. After a predefined state of the exhaust-gas aftertreatment system has been attained, the drivetrain is operated in a second operating state. The launch prohibition is inactive in the second operating state, such that launching using the engine is possible in the second operating state.

A method for heating a catalytic converter in an exhaust system of an internal combustion engine, in which an exhaust gas burner for heating the catalytic converter is arranged, upstream of the catalytic converter. A lambda probe for controlling the combustion air ratio of the exhaust gas burner is arranged immediately downstream of the exhaust gas burner and upstream of the catalytic converter. The method includes operating the internal combustion engine with a stoichiometric combustion air ratio (λ.sub.E=1), activating the exhaust gas burner, which is operated alternately with a substoichiometric combustion air ratio (λ.sub.B<1) and a superstoichiometric combustion air ratio (λ.sub.B>1), wherein from the substoichiometric combustion air ratio (λ.sub.B<1) to the superstoichiometric combustion air ratio (λ.sub.B>1) as soon as a rich breakthrough is detected by the second lambda probe (34), and wherein a switchover from the superstoichiometric combustion air ratio (λ.sub.B>1) to the substoichiometric combustion air ratio (λ.sub.B<1) takes place as soon as a lean breakthrough is detected by the second lambda probe.

Methods and systems are provided for controlling hybrid vehicle engine operation, where the vehicle engine comprises one or more cylinders dedicated to recirculating exhaust to an intake manifold. In one example, during an engine cold-start event or other event where temperature of one or more exhaust catalysts are below a temperature needed for catalytic activity, fuel injection to the dedicated exhaust gas recirculation cylinder(s) is maintained shut off, while its intake and exhaust valves are maintained activated, thus enabling the dedicated exhaust gas recirculation cylinder(s) to route air to the intake manifold of the engine, resulting in exhaust gas lean of stoichiometry that may serve to heat the catalyst. In this way, during cold start events and other events where temperature of one or more exhaust catalysts are below a temperature for catalytic activity, combustion stability issues may be avoided, and exhaust catalyst(s) rapidly heated, thereby reducing undesired tailpipe emissions.

A control apparatus for an internal combustion engine is provided. The control apparatus includes a turbocharger, a bypass passage, a wastegate valve, a catalyst device and a controller. The controller sets the wastegate valve to a closed state in a case where a warm-up execution condition is established, and performs A/F oscillation for increasing or decreasing the fuel injection amount so that lean combustion and rich combustion are alternately performed in a case where the temperature in the exhaust passage upstream of the turbocharger is beyond a predetermined reference value.

An object is to supply fresh air and EGR gas into a cylinder in good balance according to the required load in a naturally aspirated gasoline engine. When the operation state of the engine falls in a low load range, a control apparatus adjusts the degree of opening of the second throttle while keeping the first throttle fully open and controls EGR gas quantity by adjusting the degree of opening of the EGR valve. When the operation state falls in a middle load range, the apparatus controls EGR gas quantity by adjusting the degree of opening of the first throttle while keeping the EGR valve fully open. When the operation state falls in a high load range, the apparatus adjusts the degree of opening of the first throttle while keeping the second throttle fully open and controls EGR gas quantity by adjusting the degree of opening of the EGR valve.

Methods and systems are provided for operating a cylinder of an engine including a pre-chamber ignition system during a cold start condition. In one example, a method may include performing a post-injection in the cylinder, and then performing a pre-chamber combustion during an exhaust stroke of the cylinder. In this way, a temperature of a catalyst of the engine may be increased, which may decrease vehicle emissions during the cold start condition.

A method for injecting gaseous fuel directly into a combustion chamber of an internal combustion engine in order to heat a catalytic converter, the method including: carrying out a main injection of gaseous fuel directly into the combustion chamber; carrying out a first post-injection following the main injection but prior to an ignition, and following the ignition and preferably following the end of combustion in the combustion chamber, carrying out a second post-injection of gaseous fuel into the combustion chamber.

Methods and systems are provided for operating a branched exhaust assembly in a vehicle engine in order to increase catalyst efficiency and reduce engine emissions. In one example, a method may include, during a cold-start condition, flowing exhaust first through a three-way catalyst then through an underbody converter and then through a turbine, each exhaust component housed on different branches on the branched exhaust assembly. After catalyst activation, exhaust may flow first through the turbine, then through the underbody converter and then through the three-way catalyst, and during high engine load, exhaust may simultaneously flow through two branches of the branched exhaust assembly, partially bypassing the turbine.

A control apparatus for a gasoline engine having a fuel injection means including an in-cylinder injection valve. The control apparatus comprises a controller configured to, when warming up an exhaust gas purification catalyst provided in an exhaust passage provided of the gasoline engine, control the fuel injection means to conduct one or more main injections, control the in-cylinder injection valve to conduct a post injection, perform a retard correction of an ignition timing at which fuel injected by the one or more main injections is ignited, determine an injection quantity by the one or more main injections and an injection quantity by the post injection such that an air-fuel mixture formed in the cylinder by gasoline fuel injected by the one or more main injections has a predetermined lean air-fuel ratio at which a difference between an actual output torque and a required torque is within a predetermined allowable range.