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US 9,957,871 B2Granted
Exhaust heat recovery and hydrocarbon trapping
AssigneeFord Global Technologies, LLC
InventorsMichael James Uhrich, Joseph Norman Ulrey, Giovanni Cavataio, Adam Nathan Banker
Life of this patent
Estimating the term…
Abstract
Methods and systems are provided for exhaust heat recovery and hydrocarbon trapping at an exhaust bypass assembly. Exhaust gas may flow in both directions through an exhaust bypass passage and each of a HC trap and a heat exchanger coupled to the bypass passage. The HC trap may be purged with the hot exhaust and heat from the exhaust may be recovered at the heat exchanger.
Claims14
A method, comprising:
- in a first mode, flowing engine exhaust gas through an exhaust bypass and in a first direction through each of an upstream heat exchanger and then a downstream hydrocarbon trap coupled in the exhaust bypass, and then to an exhaust tailpipe;
- and
- in a second mode at a different time, flowing exhaust gas through an exhaust passage, then in a second, opposite direction through the hydrocarbon trap and then the heat exchanger, and then to an engine intake, the exhaust bypass coupled to the engine intake via an EGR passage from upstream of an inlet of the heat exchanger via an EGR valve, wherein, during the first mode, the EGR valve is closed and wherein, during the second mode, the EGR valve is opened.
A method for an engine, comprising:
- flowing exhaust gas through a heat exchanger and then a hydrocarbon trap in an exhaust bypass when engine temperature is lower than a threshold;
- and
- flowing exhaust gas through the hydrocarbon trap and then the heat exchanger in the exhaust bypass when engine temperature is higher than the threshold, wherein the flowing through the heat exchanger and then the hydrocarbon trap includes storing exhaust hydrocarbons in the hydrocarbon trap and wherein flowing through the hydrocarbon trap and then the heat exchanger includes purging exhaust hydrocarbons from the hydrocarbon trap, the method further comprising flowing the purged exhaust hydrocarbons to an engine intake via an EGR passage coupled to the exhaust bypass, upstream of the heat exchanger, after a hydrocarbon load of the hydrocarbon trap is below a threshold, and in response to a drop in engine coolant temperature, resuming flowing of exhaust gas through the heat exchanger and then the hydrocarbon trap, and transferring heat from the heat exchanger to an engine coolant.
An engine system, comprising:
- an engine intake manifold;
- an engine exhaust manifold including an exhaust catalyst and each of an exhaust passage and an exhaust bypass, the bypass coupled parallel to the exhaust passage;
- each of a heat exchanger and a hydrocarbon (HC) trap coupled in the exhaust bypass;
- a coolant system fluidly coupled to the heat exchanger and to a heater core;
- a diverter valve coupling the exhaust bypass to the exhaust passage downstream of the exhaust catalyst;
- a EGR passage coupling the exhaust bypass, upstream of the heat exchanger, to the intake manifold, the EGR passage including an EGR valve;
- and
- a controller with computer readable instructions stored on non-transitory memory for:
- closing the EGR valve and opening/closing the diverter valve to flow exhaust gas from the catalyst to a tailpipe through the exhaust bypass in a first direction through the heat exchanger and then the HC trap;
- and
- in response to an increase in engine temperature, opening the EGR valve while maintaining the diverter valve open/closed to flow exhaust gas from the catalyst, along the exhaust passage, and then through the exhaust bypass in a second direction through the HC trap and then through the heat exchanger.
8 more elements
Dependencies are inferred from the claim text.