Control of exhaust temperature in lean burn engines
AssigneeFord Global Technologies, LLC
InventorsIlya Vladimir Kolmanovsky, Julia Helen Buckland, Jing Sun
Life of this patent
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Abstract
A method (100) and system for actively controlling the temperature of engine (10) exhaust gas entering an aftertreatment device and thereby controlling undesirable emissions. Through control of the turbine blade position of a variable geometry turbocharger (16), the temperature of the exhaust gas entering the aftertreatment device is maintained within the operating temperature window for the device, and at the same time, achieves the fuel economy benefits associated with turbocharging.
Claims36
An internal combustion engine having an exhaust into an aftertreatment system comprising:
- an intake manifold path;
- a compressor in said intake manifold path;
- an exhaust manifold path;
- a turbine in said exhaust manifold path, said turbine having inlet vanes variable between an open position and a closed position for controlling the temperature of an exhaust gas exiting said turbine and entering the aftertreatment system;
- wherein during periods of stratified combustion in said internal combustion engine, changes in said inlet vane positions does not affect engine torque;
- and
- wherein during periods of homogeneous lean burn in said internal combustion engine, changes in engine operating conditions due to changes in said inlet vane positions are counteracted by altering other engine variables to maintain desired engine operating conditions independent of said inlet vane positions.
An internal combustion engine having an exhaust into an aftertreatment system comprising:
- an intake manifold having a predetermined intake path;
- a throttle positioned in said intake path;
- an exhaust manifold having a predetermined exhaust path;
- a variable geometry turbocharger for controlling temperature of exhaust gas exiting said engine, said variable geometry turbocharger comprising:
- a variable geometry turbine positioned in said exhaust path;
- a compressor positioned in said intake path;
- whereby said turbine inlet vanes are movable between an open position and a closed position, thereby altering the temperature of said exhaust gas exiting the turbine in order to maintain a predetermined temperature of said exhaust gas entering said aftertreatment system;
- wherein during periods of stratified combustion in said internal combustion engine, changes in said inlet vane positions does not affect engine torque;
- and
- wherein during periods of homogeneous lean burn in said internal combustion engine, changes in engine operating conditions due to changes in said inlet vane positions are counteracted by altering other engine variables to maintain desired engine operating conditions independent of said inlet vane positions.
A method for controlling the temperature of exhaust gas exiting a variable geometry turbine in an engine having a set of system operating conditions comprising the steps of:
- sensing a temperature of exhaust gas within an aftertreatment device;
- determining whether said sensed temperature is within a predetermined temperature range;
- using said variable geometry turbine to maintain said exhaust gas temperature within said predetermined temperature range;
- and
- adjusting a plurality of system operating variables in order to maintain said set of system operating conditions.
A method for controlling the temperature of exhaust gas exiting a variable geometry turbine comprising the steps of:
- estimating a temperature of exhaust gas within an aftertreatment device;
- determining whether said estimated temperature is within a predetermined temperature range;
- using said variable geometry turbine to maintain said exhaust gas temperature within said predetermined temperature range;
- and
- adjusting a plurality of engine operating variables in order to maintain said set of system operating conditions.
Dependencies are inferred from the claim text.