Apparatus and method for optimizing exhaust temperature control in a vehicle during particulate filter regneration
First Claim
1. A method for controlling a temperature of an exhaust gas from a vehicle engine during regeneration of a particulate filter (PF) in a vehicle having an oxidation catalyst (OC), a selective catalytic reduction catalyst (SCR), and the PF, the method comprising:
- adjusting a concentration of hydrocarbons in the exhaust gas to thereby achieve a first temperature set point;
determining a second temperature set point corresponding to a PF inlet temperature;
subtracting the second temperature set point from a measured PF inlet temperature to thereby calculate an error term;
adding the error term to the first temperature set point to thereby determine a target OC outlet temperature; and
executing a control action during the regeneration of the PF to thereby ensure that a final OC temperature does not exceed a maximum of the target OC outlet temperature and a calibrated maximum OC outlet temperature.
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Accused Products
Abstract
A method controls an exhaust gas temperature from a vehicle engine during regeneration of particulate filter (PF) in a vehicle having an oxidation catalyst (OC) and a selective catalytic reduction catalyst (SCR). The method ensures that a final OC temperature does not exceed a maximum of the target OC outlet temperature and a calibrated maximum OC outlet temperature. An apparatus for controlling a temperature of the exhaust gas includes sensors for measuring a temperature within the exhaust system and a controller having an algorithm, an OC temperature lookup table, and a PF temperature lookup table. The algorithm calculates a target OC outlet temperature using the lookup tables and a delayed error value that compensates for a thermal mass of the SCR. Actual OC outlet temperature is limited during regeneration of the PF to the lesser of the target OC outlet temperature and a calibrated maximum OC outlet temperature.
14 Citations
14 Claims
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1. A method for controlling a temperature of an exhaust gas from a vehicle engine during regeneration of a particulate filter (PF) in a vehicle having an oxidation catalyst (OC), a selective catalytic reduction catalyst (SCR), and the PF, the method comprising:
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adjusting a concentration of hydrocarbons in the exhaust gas to thereby achieve a first temperature set point; determining a second temperature set point corresponding to a PF inlet temperature; subtracting the second temperature set point from a measured PF inlet temperature to thereby calculate an error term; adding the error term to the first temperature set point to thereby determine a target OC outlet temperature; and executing a control action during the regeneration of the PF to thereby ensure that a final OC temperature does not exceed a maximum of the target OC outlet temperature and a calibrated maximum OC outlet temperature. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for controlling a temperature of an exhaust gas from an engine during regeneration of a particulate filter (PF) in a vehicle having an oxidation catalyst (OC), a selective catalytic reduction catalyst (SCR), and the PF, the method comprising:
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selecting a first temperature set point from a first lookup table, the first temperature set point corresponding to an OC outlet temperature; selecting a second temperature set point from a second lookup table, the second temperature set point corresponding to a PF inlet temperature; measuring an actual PF inlet temperature; subtracting the second temperature set point from the actual PF inlet temperature to calculate an error term; filtering the error term to thereby compensate for a known thermal mass of the SCR; adding the error term to the first temperature set point to determine a target OC outlet temperature; and controlling an actual OC outlet temperature during the regeneration of the PF such that the actual OC outlet temperature does not exceed a maximum of the target OC outlet temperature and a calibrated maximum OC outlet temperature. - View Dependent Claims (10, 11)
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12. An apparatus for controlling a temperature of an exhaust gas within an exhaust system of a vehicle engine during regeneration of a particulate filter (PF), the exhaust system having an oxidation catalyst (OC), a selective catalytic reduction catalyst (SCR), and the PF, the apparatus comprising:
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a plurality of sensors each operable for measuring a temperature within a different portion of the exhaust system; and a controller having an algorithm, a OC outlet temperature lookup table, and a PF inlet temperature lookup table, each of the lookup tables being indexed by a plurality of engine operating values; wherein the algorithm is adapted to calculate a target OC outlet temperature using data from each lookup table, the target OC outlet temperature compensating for a thermal mass of the SCR; and wherein the algorithm limits an actual OC outlet temperature during regeneration of the PF to the lesser of the target OC outlet temperature and a calibrated maximum OC outlet temperature. - View Dependent Claims (13, 14)
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Specification