# US 9,435,242 B2 · Device and method for purifying exhaust gases for an internal combustion engine

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- Number: US 9,435,242 B2
- Document ID: US9435242B2
- Status: Granted
- Kind: B2
- Application number: 12/674,457
- Filed: 2008-07-11
- Published: 2011-08-04
- Granted: 2016-09-06
- Earliest claimed: 2007-08-22
- Assignees: Audi AG
- Applicants: Andre Kopp
- Inventors: Andre Kopp
- Web page: https://patentgrep.com/patent/US9435242B2

## CPC

- F01N 3/2073: {Means for generating a reducing substance from the exhaust gases}
- B01D 53/9481: {Catalyst preceded by an adsorption device without catalytic function for temporary storage of contaminants, e.g. during cold start}
- F01N 3/0814: {combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts}
- F01N 3/2053: {By-passing catalytic reactors, e.g. to prevent overheating}
- F01N 13/02: having two or more separate silencers in series
- F01N 13/04: having two or more silencers in parallel, e.g. having interconnections for multi-cylinder engines
- F01N 13/107: {More than one exhaust manifold or exhaust collector}
- F02D 41/0082: {per groups or banks (F02D41/0087 takes precedence)}
- F02D 41/0275: {the exhaust gas treating apparatus being a NOx trap or adsorbent}
- B01D 53/9418: {for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas}
- B01D 2251/2062: Ammonia
- B01D 2255/911: NH3-storage component incorporated in the catalyst
- F01N 2240/25: an ammonia generator
- F01N 2240/36: an exhaust flap
- F01N 2560/026: for measuring or detecting NOx
- Y02A 50/20: Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
- Y02T 10/12: Improving ICE efficiencies
- F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W)
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

The invention relates to a device and a method for purifying exhaust gases for an internal combustion engine, with a multi-flow exhaust gas system having, at least in individual regions, several partial exhaust gas lines, and in which a NOx storage catalytic converter device and a SCR catalytic converter device are located. According to the invention, the NOx storage catalytic converter device (7) and the SCR catalytic converter device (9) are arranged distributed on different partial exhaust gas lines (6, 8) such that for a nitrogen oxide-Filled nitrogen oxide store of the NOx storage catalytic converter device (7) for a specified time interval a defined amount of the exhaust gas flow (16) produced by substoichiometric rich operation of the internal combustion engine (2) for production of a reducing agent, in particular for producing ammonia, flows via the NOx storage catalytic converter device (7) to the SCR catalytic converter device (9), in which the produced reducing agent, in particular ammonia, can be stored.

## Claims

### Claim 1

A system for purifying the exhaust gases of an internal combustion engine comprising:
a first exhaust gas line connected to a first set of cylinders of said engine, including a catalytic converter functional to store NOx upon lean operation of said first set of cylinders;
a second exhaust gas line connected to a second set of cylinders of said engine, including a catalytic converter functional to store ammonia, wherein during lean operation of the first set of cylinders, a first partial exhaust gas flows through the first exhaust gas line and a second partial exhaust gas flows through the second exhaust gas line; and
means responsive to a selected storage capacity of NOx in said first mentioned catalytic converter and a substoichiometric rich operation of said first set of cylinders for unilaterally diverting the flow of gases in said first exhaust gas line downstream of said first mentioned catalytic converter through an intermediate cross-connection to said second exhaust line upstream of said second mentioned catalytic converter while simultaneously blocking the first partial exhaust gas flow through the first exhaust gas line downstream of the intermediate cross-connection.

### Claim 2 (depends on 1)

The system according to claim 1 including means for operating said second set of cylinders at a lean stoichiometric ratio during substoichiometric operation of said first set of cylinders.

### Claim 3

A method of purifying the exhaust gases of an internal combustion engine comprising:
conducting a first stream of exhaust gases from a first set of cylinders of said engine along a first exhaust gas line including an NOx storage catalytic converter during a lean operation of the first set of cylinders;
conducting a second stream of exhaust gases from a second set of cylinders of said engine along a second exhaust line including a catalytic converter with ammonia storage capability during the lean operation of the first set of cylinders;
sensing a selected capacity of said NOx storage catalytic converter; and
diverting the flow of said first stream of exhaust gases from said first exhaust gas line downstream of said NOx storage catalytic converter through an intermediate cross-connection to said second exhaust gas line upstream of said catalytic converter with ammonia storage capability while simultaneously blocking the first stream of exhaust gases through the first exhaust gas line downstream of the intermediate cross-connection, and operating said first set of cylinders at a substoichiometric rich ratio, responsive to sensing said selected capacity of said NOx storage catalytic converter.

### Claim 4 (depends on 3)

The method of claim 3 including operating said second set of cylinders at a lean stoichiometric ratio.