Methods and systems for operating an engine that includes a catalyst and a particulate filter are described. In one example, release of reductant from an injector may be determined according to a plurality of metrics so that reliability of a release indication may be improved. In addition, operation of an engine may be adjusted responsive to the release indication so that exhaust system temperatures may be maintained.

Methods and systems are provided for fuel post injection for diesel particulate filter (DPF) regeneration. In one example, a method may include, responsive to a request for generating exotherms in an exhaust system of an engine while combustion is discontinued in at least one cylinder of the engine, injecting fuel into a cylinder within a threshold crank angle range around top dead center (TDC) of a compression stroke of the cylinder and also within the threshold crank angle range around top dead center of an exhaust stroke of the cylinder, the threshold crank angle range extending from no more than 40 crank angle degrees before TDC to no more than 40 crank angle degrees after TDC. In this way, fuel post injections may be injected +/−40 crank angle degrees after TDC of the compression and exhaust strokes to increase exhaust temperature while avoiding wall wetting and oil-in-fuel dilution.

A method of starting up a thermoreactor arranged in an exhaust gas flow of an internal combustion engine includes igniting combustion gas by spark ignition in at least one cylinder of the internal combustion engine. The exhaust gas resulting from the combustion of the combustion gas is fed at least partially to the thermoreactor as an exhaust gas flow. The temperature of the exhaust gas resulting from combustion of the combustion gas is increased by the moment in time of the spark ignition being selected later in comparison with a present moment in time.

A heater for use in heating a fluid flow through a passageway is provided that includes a continuous resistive heating element having a predefined shape that is directly exposed to the fluid flow. The predefined shape includes a cross-sectional geometry that provides a required heat distribution, structural strength, and reduced back pressure within the passageway. The predefined shape may include airfoils, while the cross-sectional geometry provides a required heat distribution, structural strength, and reduced back pressure within the passageway.

When a catalytic converter in an exhaust passage is in an un-activated state, an intake air amount is increased, as compared to when the converter is in an activated state under the same engine operation condition, and an ignition timing is retarded beyond a TDC of a compression stroke. The ignition timing is set such that a retard amount thereof from the TDC becomes larger as an external load causing a rotational resistance of an engine becomes lower. A valve opening start timing of an exhaust valve is set such that, when the external load is lower than a given reference load, the valve starts opening, before an in-cylinder pressure reaches a peak, according to combustion of an air-fuel mixture ignited at the above ignition timing, in a subsequent expansion stroke, wherein the in-cylinder pressure is based on an assumption that the valve is maintained in a valve-closed state.

A PCM (60) performs a catalyst early warming control (AWS control) for accelerating warm-up of a catalytic device. When the catalytic device (35) is not in an activated state and a vehicle is traveling, the PCM (60) is configured to perform: a fuel injection control to inject fuel such that a homogeneous fuel-air mixture can be formed in a combustion chamber (11) of an engine (10) so as to generate a homogeneous combustion; an intake air amount control to increase intake air amount; and an ignition control to retard ignition timing from a reference ignition timing. In addition, the PCM (60) is configured to vary ignition timing retard amount corresponding to a difference between the ignition timing retarded by the ignition timing control and the reference ignition timing, in accordance with engine speed and/or engine load.

A method for preheating a catalytic converter which is arranged in the exhaust-gas flow of a motor vehicle and which has an electrically heated catalyst is described. The catalytic converter is preheated with the electrically heated catalyst to a maximum temperature within a period of time before the initial engine starting operation. In the process, the temperature of the electrically heated catalyst and the battery state of the vehicle are monitored. During the preheating, it is checked whether or not the battery state has fallen below a state threshold. If so, the heating of the electrically heated catalyst is stopped, and engine-internal measures are implemented. If not, further heating of the electrically heated catalyst is implemented until the maximum temperature is reached again.

System and methods are described for optimizing exhaust flow rate and temperature during specified operational periods warm-up and keep-warm conditions, by minimizing or maximizing heat flux during those specified operational periods.

Provided is a pre-chamber type diesel engine wherein the fuel system is not complicated, regardless of whether a regeneration function is provided. An injector is employed, which is able to inject fuel at a given timing by means of an electrical signal from a controller, and when a prescribed amount of particles have been trapped in a particle collection filter the injector carries out an additional fuel injection during the expansion stroke of a piston.

Methods and systems are provided for protecting an exhaust catalyst from degradation during a DFSO event. Exit from DFSO due to pedal input received from an operator with a jittery foot is averted by filtering the pedal input differently when operating in a DFSO mode as compared to when operating out of the DFSO mode. Exit from DFSO is confirmed after receiving a higher than threshold pedal position input for a sustained period of time, or when an integrated fuel injection amount exceeds a threshold amount.