Methods and systems for reducing hydrocarbon emissions
AssigneeFord Global Technologies, LLC
InventorsXiaogang Zhang, Daniel Styles
Life of this patent
Estimating the term…
Abstract
Methods and systems for heating an emission control device are provided. In one example, a method for a vehicle comprises during an engine cold start, heating an emission control device of the engine using a dual heat exchanger to heat secondary air and cool exhaust gas, and further heat secondary air with an electric heater. The method further comprises directing the heated secondary air to each exhaust runner of the engine via individual air injectors to mix with exhaust gas. In this way, an improved mixture of air and exhaust reduces catalyst light-off time and increases conversion efficiency, thereby reducing hydrocarbon emissions during engine cold start.
Claims19
A method for a vehicle, comprising:
- during an engine cold start of an engine,
- heating an emission control device coupled downstream of the engine using a dual heat exchanger to simultaneously heat secondary air and cool exhaust gas, and further heating the secondary air with an electric heater, including flowing the secondary air through the dual heat exchanger to the electric heater and from the electric heater to the engine.
A system for a vehicle, comprising:
- an engine having a secondary air injection passage and an EGR passage;
- an emission control device coupled to an exhaust passage of the engine;
- a dual heat exchanger coupled to the secondary air injection passage and to the EGR passage;
- an electric heater coupled to the secondary air injection passage downstream of the dual heat exchanger and upstream of the engine;
- and
- a controller storing instructions in non-transitory memory that, when executed, cause the controller to:
- responsive to a cold start of the engine, heat the emission control device using the dual heat exchanger to heat air flowing through the secondary air injection passage and cool exhaust gas flowing through the EGR passage, and further heat the air by activating the electric heater.
A method for an engine, comprising;
- responsive to a cold start of the engine, opening an EGR valve positioned in an EGR passage to flow exhaust gas from upstream of a turbine through the EGR passage, and activating a PETA air pump positioned in a secondary air injection passage to flow secondary air from downstream of a compressor through the secondary air injection passage;
- simultaneously heating the secondary air and cooling the exhaust gas using a dual heat exchanger, the dual heat exchanger being coupled to the EGR passage and the secondary air injection passage downstream of the EGR valve and the PETA air pump, the dual heat exchanger including a first plurality of passages fluidly coupled to the EGR passage and configured to flow the exhaust gas and a second plurality of passages fluidly coupled to the secondary air injection passage and configured to flow the secondary air, wherein the first plurality of passages and second plurality of passages maintain the exhaust gas in fluidic isolation from the secondary air;
- heating the secondary air further with an electric heater coupled to the secondary air injection passage downstream of the dual heat exchanger;
- and
- selectively directing the secondary air from the electric heater to a plurality of exhaust runners via a plurality of air injectors to mix the secondary air with the exhaust gas, including adjusting each of a plurality of flow control valves to selectively direct the secondary air to the plurality of exhaust runners, each respective flow control valve positioned upstream of a respective air injector.
Dependencies are inferred from the claim text.