A catalytic wall-flow monolith filter having three-way catalytic activity for use in an emission treatment system of a positive ignition internal combustion engine comprising a porous filter substrate having a first face and a second face defining a longitudinal direction there between and first and second pluralities of channels extending in the longitudinal direction, wherein the first plurality of channels is open at the first face and closed at the second face and the channels of the first plurality of channels are defined in part by channel wall surfaces, wherein the second plurality of channels is open at the second face and closed at the first face and the channels of the second plurality of channels are defined in part by channel wall surfaces and wherein channel walls between the channel wall surfaces of the first plurality of channels and the channel wall surfaces of the second plurality of channels are porous, wherein a first on-wall coating comprising catalytic material having a layer thickness is present on at least the channel wall surfaces of the first plurality of channels, wherein the catalytic material on channel wall surfaces of the first plurality of channels comprises one or more platinum group metal selected from the group consisting of (i) rhodium (Rh) only; (ii) palladium (Pd) only; (iii) platinum (Pt) and rhodium (Rh); (iv) palladium (Pd) and rhodium (Rh); and (v) platinum (Pt), palladium (Pd) and rhodium (Rh) and a refractory metal oxide support, wherein: (i) an amount by weight of the one or more platinum group metal, per unit volume of the on-wall coating present on channel wall surfaces of the first plurality of channels varies continually along the longitudinal direction; and/or (ii) the layer thickness of the on-wall coating present on channel wall surfaces of the first plurality of channels varies continually along the longitudinal direction.

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.

A system and method that forwards information concerning the condition of the particulate filter (14) in each fleet vehicle to a remote station (56). This information is sorted (114) and displayed (62) to a human operator, who then makes a decision regarding particulate filter maintenance, on a fleet wide basis (116). The human operator may select a set of vehicles to undergo filter regeneration during a particular time slot, at a facility with a limited capacity to perform filter regeneration during any particular time slot. Typically, this will be overnight, for example for a metropolitan bus service that is busy during the day but has greatly reduced or nonexistent service at nighttime.

Various embodiments include a diesel engine comprising: an exhaust gas line; a diesel particulate filter arranged in the exhaust gas line; a first NO sensor arranged in the exhaust gas line upstream of the diesel particulate filter; and a second NO sensor arranged in the exhaust gas line downstream of the diesel particulate filter.

Provided is a diesel engine capable of regenerating a DPF even during no-load and/or light-load operation. In a DPF regeneration process, opening-degree reduction control S2 for an exhaust-air throttle valve is performed after a start condition S1 of the regeneration process of the DPF in which PM is deposited is satisfied. When exhaust air reaches a temperature equal to or higher than a predetermined after-injection permissible temperature TA, after-injection control is subsequently started S5. Post-injection control is started S7 after the exhaust air reaches a temperature equal to or higher than a predetermined post-injection permissible temperature TP by combustion of after-injection fuel. The PM deposited in the DPF is incinerated by the exhaust air increased in temperature by catalytic combustion of post-injection fuel in a valve downstream-side DOC.

A method of using a radio frequency sensor for determining an estimate of soot load in a diesel particulate filter is disclosed, The method comprises: receiving a first mean attenuation value derived from attenuation values for each of a first plurality of radio frequencies within a first band of radio frequencies detected by the radio frequency sensor; and receiving first standard deviation data for the mean attenuation value relating to the first plurality of radio frequencies within the first band of radio frequencies. The method further comprises: determining whether the standard deviation data exceeds a standard deviation threshold, In the event that the standard deviation data does not exceed a standard deviation threshold, the method uses the first mean attenuation value to infer a value for soot load in the diesel particulate filter, in the event that the standard deviation data exceeds a standard deviation threshold, the method comprises: receiving a second mean attenuation value derived from attenuation values for each of a second plurality of radio frequencies within a. second band of radio frequencies; and receiving second standard deviation data relating to the mean attenuation value for a second plurality of radio frequencies within the second band of radio frequencies detected by the radio frequency sensor, In the event that the second standard deviation data does not exceed the standard deviation threshold, the method uses the second mean attenuation value to infer the value for soot load in the diesel particulate filter.

The exhaust purification system of an internal combustion engine includes a filter trapping particulate matter in exhaust gas flowing through an exhaust passage of the internal combustion engine and supporting a three-way catalyst, and a filter regeneration part configured to perform regeneration processing for oxidizing and removing particulate matter deposited on the filter when predetermined conditions are satisfied. The filter regeneration part is configured to increase an NO concentration in exhaust gas flowing into the filter when the predetermined conditions are satisfied compared to when the predetermined conditions are not satisfied.

A method comprises determining that an aftertreatment system is in a cold-operation mode; initiating a low engine-out NOx (LEON) mode by controlling a component of a vehicle containing the aftertreatment system to decrease an instantaneous engine out NOx (EONOx) amount and to increase exhaust energy relative to a normal operation mode for an engine of the vehicle; receiving information indicative of an operating status of the vehicle during the LEON mode; disengaging the LEON mode; subsequent to disengaging the LEON mode, initiating a thermal management (TM) mode for the aftertreatment system, wherein the TM mode is initiated by controlling a component of the vehicle to increase fueling to the engine for a power level by reducing engine efficiency and directing excess fuel to the aftertreatment system; receiving information indicative of an operating status of the vehicle during the TM mode; and disengaging the TM mode.

When a temperature increasing process is performed, a CPU sets a target temperature of a catalyst to be lower when a coolant temperature is low than when the coolant temperature is high. The CPU decreases an increase coefficient of fuel in the temperature increasing process when a value obtained by subtracting an estimated value of a temperature of the catalyst from the target temperature is equal to or less than a first prescribed value.

A method, system, and apparatus relating to operating an internal combustion engine include steps or features for determining a performance threshold of a particulate filter disposed in an exhaust gas flow of the engine having a set time interval between regeneration events of the particulate filter; determining a rate at which the particulate filter is reaching the performance threshold; and controlling an exhaust gas characteristic to control the rate so that the performance threshold is reached at or just before an end of the time interval. In an embodiment, there are steps or features for interpreting a filter condition of the particulate filter; determining a particulate matter load rate of the filter as a function of the condition; determining a limit of an exhaust gas characteristic based on the load rate; and controlling engine operation to control the exhaust gas characteristic to satisfy the limit.