A heavy duty truck includes a diesel engine that generates an exhaust gas flow and an exhaust after-treatment system for treatment of the exhaust gas flow. The exhaust after-treatment system includes at least one temperature sensor at an underbody SCR system within the exhaust after-treatment system and a DEF injector upstream of a close-coupled SCR system within the exhaust after-treatment system. The DEF injector is operated to inject DEF into the exhaust gas flow at a rate that varies as a function of a temperature measured by the temperature sensor.

An exhaust purification system may include at least one catalyst in an exhaust flow path of an internal combustion engine to decrease gaseous pollutants from an exhaust gas, a first particulate filter downstream of the catalyst, and a second particulate filter with a porosity lower and a lower mean pore size than the first particulate filter and in a bypass flow line downstream of the first particulate filter, the bypass flow line being configured to open and close based on at least one condition of the exhaust purification system or conditions of the exhaust gas. The second particulate filter may be configured to be removed and replaced when full. A method of purifying an exhaust gas through the exhaust purification system is also described.

An apparatus for a gas turbine power plant that uniquely configures emission control equipment such that the plant can extend the emissions compliant operational range, the apparatus including a plurality of oxidation (CO) catalysts arranged in series.

An exhaust aftertreatment unit for cleaning exhaust gases. The exhaust aftertreatment unit includes an emission reducing module being a diesel particulate filter, DPF, and/or a diesel oxidation catalyst, DOC, a selective catalyst reduction, SCR, catalyst, an electrical heating element arranged upstream of the SCR catalyst, a casing housing at least the emission reducing module, and a service lid removably arranged to cover a service opening of the casing through which the emission reducing module may be accessed. The electrical heating element is removably arranged relative the casing and is arranged accessible upon removal of the service lid.

An exhaust system that includes a catalytic converter, selective catalytic reduction system, a muffler and, for certain applications, a diesel particulate filter that each include at least one filter that has an electric heating element, a metallic coating and a plurality of metal rods extending therethrough. The combination of elements are configured to heat the internal housings of the exhaust system and disrupt the direction of flow of exhaust gases which contain harmful toxic gases and pollutants and aid in removing and/or reducing said toxic gases and pollutants.

Methods, apparatuses, and systems for managing a multiple, and particularly a dual-selective catalyst reduction (SCR), exhaust aftertreatment system according to one or more determined reductant dosing strategies are disclosed. A method includes: receiving, by a controller, data indicative of a catalyst of an aftertreatment system; determining, by the controller, a reductant dosing strategy based on a comparison of the data indicative of the catalyst to a respective threshold; and commanding, by the controller, an amount of reductant dosing based on the determined reductant dosing strategy.

In a method and a device for monitoring the operability of an emission control system of an internal combustion engine, at least two catalytic converters are situated in succession in an exhaust duct. For tracking control, breakthrough detection for diagnosing the first catalytic converter, and for a second balancing for the storage capacity of oxygen or rich gas of the second catalytic converter, a two-point lambda probe be used and, for the latter, tolerance and aging effects are compensated. This results in particular in cost advantages in emission control systems for fulfilling stricter emission and diagnostic requirements.

An exhaust system includes a selective catalytic reduction (SCR) catalyst, a diesel oxidation catalyst, and an ammonia slip catalyst. The SCR catalyst is configured to reduce nitrogen oxide in exhaust gas produced by a diesel engine. The diesel oxidation catalyst is configured to reduce particulate matter, hydrocarbon, and carbon monoxide in the exhaust gas. The diesel oxidation catalyst is disposed downstream of the first SCR catalyst. The ammonia slip catalyst is configured to reduce ammonia in the exhaust gas. The ammonia slip catalyst is disposed downstream of the first SCR catalyst and upstream of the first diesel oxidation catalyst.

A SCR device includes a substrate having a first portion, and a second portion disposed downstream of the first portion. The first portion of the substrate includes a volume that is between 15% and 25% of a total volume of the substrate. A first selective catalytic reduction compound is disposed on the first portion of the substrate, and includes an iron zeolite (Fe-Zeolite) compound. A second selective catalytic reduction compound is disposed on the second portion of the substrate, and includes a copper (Cu) SAPO-34 compound. The copper SAPO-34 compound includes a catalyst density of less than 2.74 mg copper per cubic centimeter of copper SAPO-34 compound. The copper SAPO-34 compound is applied onto the second portion of the substrate at a compound density of less than 110 g of copper SAPO-34 compound per liter of volume of the second portion of the substrate.

A method for controlling an exhaust gas aftertreatment system, wherein the system includes a first selective catalytic reduction (SCR) device, a catalytic particulate filter arrangement arranged downstream of the first SCR device, and a second selective catalytic reduction (SCR) device arranged downstream of the catalytic particulate filter arrangement. The method includes estimating future exhaust conditions based upon predicted vehicle operating conditions (s403); —estimating a future NOx conversion demand based on the estimated future exhaust conditions (s405); —dosing a reducing agent from a first reducing agent dosing device at a rate based at least on the estimated future NOx conversion demand (s406).