Method and system for emissions reduction
AssigneeFord Global Technologies, LLC
InventorXiaogang Zhang
Life of this patent
Estimating the term…
Abstract
Methods and systems are provided for operating a branched exhaust assembly in a vehicle engine in order to increase catalyst efficiency and reduce engine emissions. In one example, a method may include, during a cold-start condition, flowing exhaust first through a three-way catalyst then through an underbody converter and then through a turbine, each exhaust component housed on different branches on the branched exhaust assembly. After catalyst activation, exhaust may flow first through the turbine, then through the underbody converter and then through the three-way catalyst, and during high engine load, exhaust may simultaneously flow through two branches of the branched exhaust assembly, partially bypassing the turbine.
Claims20
A method, comprising:
- during an engine cold-start, flowing exhaust first through a three-way catalyst, then through an underbody converter, and then a turbine;
- after catalyst light-off, flowing exhaust first through the turbine, then through the underbody converter, and then through the three-way catalyst;
- and
- during high load operation, bypassing the turbine at least partially.
An engine method, comprising:
- adjusting a position of a plurality of valves coupled to each of a first, second, and third branch of a branched exhaust system, each branch housing a distinct exhaust component, to vary an order of exhaust flow through the distinct exhaust components while flowing exhaust through each of the distinct exhaust components, wherein the adjusting includes:
- operating in a first mode with a first valve in a first position and a second valve in a first position to flow exhaust first through a three-way catalyst housed on the third branch of the branched exhaust system, then through an underbody converter housed on the second branch of the branched exhaust system, and then through a turbine housed on the first branch of the branched exhaust system;
- operating in a second mode with the first valve in a second position and the second valve in a second position to flow exhaust first through the turbine, then through the underbody converter, and then through the three-way catalyst;
- and
- operating in a third mode with the first valve in a third position and the second valve in the second position to flow a first portion of exhaust first through the turbine, then through the underbody converter, and then through the three-way catalyst, and to flow a second portion of exhaust through the three-way catalyst bypassing the turbine and the underbody converter.
An engine system, comprising:
- an engine intake manifold;
- an exhaust assembly with a first branch, a second branch, a third branch, a first valve, and a second valve;
- a turbocharger with a turbine coupled to the first branch of the exhaust assembly, the turbine connected to a compressor;
- an underbody converter coupled to the second branch of the exhaust assembly;
- and
- a controller with computer readable instructions stored on non-transitory memory for:
- adjusting each of the first valve and the second valve to flow exhaust through each of the turbine, the underbody converter, and a three-way catalyst via each of the first branch, the second branch, and the third branch, wherein an order of flowing exhaust is based on engine temperature and engine load.
Dependencies are inferred from the claim text.