Modulating flow through an exhaust gas recirculation cooler to maintain gas flow velocities conducive to reducing deposit build-ups
AssigneeGM Global Technology Operations LLC
InventorsAlexander Knafl, Patrick G. Szymkowicz
Life of this patent
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Abstract
A heat exchanger of motor vehicle processes a gas flow including combustion exhaust gas. Combustion by-product deposit build-up within the heat exchanger is reduced by maintaining a minimum gas flow velocity within the heat exchanger by reducing heat exchanger total gas flow cross section to locally increase a gas flow velocity.
Claims18
Method to reduce combustion by-product deposit build-up within a heat exchanger of a motor vehicle, wherein said heat exchanger processes a gas flow including exhaust gas, by maintaining a minimum exhaust gas recirculation flow velocity within the heat exchanger, the method comprising:
- determining the minimum exhaust gas recirculation flow velocity selected based on avoiding excessive fouling rates;
- reducing a heat exchanger total gas flow cross section to locally increase an exhaust gas recirculation flow velocity, the locally increased exhaust gas recirculation flow velocity maintains the minimum exhaust gas recirculation flow velocity by offsetting decreases in exhaust gas recirculation flow velocity resulting from cooling of the exhaust gas recirculation flow through the length of the heat exchanger;
- and
- wherein the exhaust gas recirculation flow comprises a diverted portion of an exhaust gas flow utilized for controlling combustion within a combustion chamber.
Apparatus for reducing combustion by-product deposit build-up within a heat exchanger of a motor vehicle, wherein said heat exchanger processes an exhaust gas recirculation flow including exhaust gas, comprising:
- a plurality of gas flow passages within said heat exchanger, said gas flow passages comprise tapered gas flow passages with gradually reducing cross sections in the direction of gas flow increasing the resulting exhaust gas recirculation flow velocity within said heat exchanger;
- a flow control door operating in close proximity to said heat exchanger and selectively blocking a portion of said heat exchanger, such that exhaust gas recirculation flow is blocked from flowing through said portion in a substantially binary manner thereby reducing the cross section of the heat exchanger through which the exhaust as recirculation flow passes within said heat exchanger and increasing the resulting exhaust gas recirculation flow velocity within said heat exchanger;
- an actuator for controlling said flow control door;
- and
- wherein increasing the resulting exhaust gas recirculation flow velocity within said heat exchanger maintains a minimum exhaust gas recirculation flow velocity selected based on avoiding excessive fouling rates and said tapered gas flow passages with gradually reducing cross sections offsets decreases in exhaust gas recirculation flow velocity resulting from cooling of the exhaust gas recirculation flow through the length of said plurality of gas flow passages within said heat exchanger;
- wherein the exhaust gas recirculation flow comprises a diverted portion of an exhaust gas flow utilized for controlling combustion within a combustion chamber.
Apparatus for reducing combustion by-product deposit build-up within a heat exchanger of a motor vehicle, wherein said heat exchanger processes a gas flow including exhaust gas, comprising:
- said heat exchanger including a plurality of gas flow passages, wherein said gas flow passages comprise tapered gas flow passages with gradually reducing cross sections in the direction of gas flow, said tapered gas flow passages each comprising a gas flow entrance wider than a respective gas flow exit.
Dependencies are inferred from the claim text.