Methods and systems for heating an emission control device are provided. In one example, a method for a vehicle comprises during an engine cold start, heating an emission control device of the engine using a dual heat exchanger to heat secondary air and cool exhaust gas, and further heat secondary air with an electric heater. The method further comprises directing the heated secondary air to each exhaust runner of the engine via individual air injectors to mix with exhaust gas. In this way, an improved mixture of air and exhaust reduces catalyst light-off time and increases conversion efficiency, thereby reducing hydrocarbon emissions during engine cold start.

A method for controlling a powertrain of a hybrid vehicle includes the following steps performed by a hybrid controller: determining whether an ambient air temperature is lower than a predetermined temperature; driving a motor and operating a heating disc of an electrically heated catalytic converter disposed in an exhaust pipe of an internal combustion engine during a predetermined operating time when an ambient air temperature is lower than a predetermined temperature; supplying ambient air to the heating disc; and varying a flow rate of the ambient air supplied to the heating disc in response to a temperature change of the heating disc.

A method for monitoring a secondary airflow (SAIR) system in an engine includes determining degradation of the SAIR system adding a SAIR to downstream of an engine cylinder exhaust based on a comparison of the SAIR before and after a shutdown of a SAIR pump, the SAIR calculated from a fuel injection amount, an exhaust air-fuel ratio, and an engine intake airflow. In this way, SAIR at the exhaust manifold can be monitored utilizing existing onboard sensors and technology, thereby maintaining OBD and emissions monitoring, reducing engine emissions, and maintaining costs.

A method for monitoring a secondary airflow (SAIR) system in an engine includes determining degradation of the SAIR system adding a SAIR to downstream of an engine cylinder exhaust based on a comparison of the SAIR before and after a shutdown of a SAIR pump, the SAIR calculated from a fuel injection amount, an exhaust air-fuel ratio, and an engine intake airflow. In this way, SAIR at the exhaust manifold can be monitored utilizing existing onboard sensors and technology, thereby maintaining OBD and emissions monitoring, reducing engine emissions, and maintaining costs.

Methods and systems for heating an emission control device are provided. In one example, a method for a vehicle comprises during an engine cold start, heating an emission control device of the engine using a dual heat exchanger to heat secondary air and cool exhaust gas, and further heat secondary air with an electric heater. The method further comprises directing the heated secondary air to each exhaust runner of the engine via individual air injectors to mix with exhaust gas. In this way, an improved mixture of air and exhaust reduces catalyst light-off time and increases conversion efficiency, thereby reducing hydrocarbon emissions during engine cold start.

An exhaust gas aftertreatment system for an internal combustion engine has an exhaust system that can be connected to an outlet of the internal combustion engine. A three-way catalytic converter that is situated close to the engine and, downstream from the three-way catalytic converter that is situated close to the engine, a second catalytic converter and a particle reduction device are arranged in the direction in which an exhaust gas of the internal combustion engine flows through an exhaust gas channel of the exhaust system. A fuel injector is arranged on the exhaust gas channel so as to inject fuel downstream from the three-way catalytic converter that is situated close to the engine and upstream from the second catalytic converter, and the exhaust system comprises a secondary air system with which secondary air can be blown into the exhaust gas channel downstream from the three-way catalytic converter that is situated close to the engine and upstream from the second catalytic converter.

Methods and systems using model based and iterative calculations of mass flow throughout an internal combustion engine system. A secondary air injection valve is provided to selectively allow intake air to pass to the exhaust side of the engine system to aid in exothermic reaction with exhaust gasses exiting the engine for various purposes. The iterative calculations of mass flow include estimation of the mass flow through the secondary air injection valve.

Aspects of the present invention relate to a valve seat (20) for a poppet valve of an internal combustion engine, wherein the poppet valve comprises a head and a stem behind the head, the valve seat comprising: an aperture (21) configured to form a seal with the head of the poppet valve when the poppet valve is in a closed position; and a peripheral body (22) defining, at least in part, one or more ports (23) shaped like e.g. grooves and sized to enable injection of liquid or gas from a cylinder head of the internal combustion engine into a gas stream behind the head of the poppet valve.

In an internal combustion engine system having an emissions control system including an electrically heated catalyst (E-cat) and an E-compressor (either standalone or part of an E-turbocharger), a method for operating the emissions control system includes predicting that a cold start of the engine is imminent, activating the E-cat and the E-compressor in response to the prediction, and monitoring a characteristic parameter Pe of the E-cat as it changes. The E-compressor speed Nc is regulated to change in proportion to the changing Pe while the E-cat is activated. If no engine start occurs, the E-cat is deactivated, and speed Nc is regulated to track the changing Pe.

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.