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US 9,175,622 B2Granted
Engine emission control strategy for smoke and NOx
AssigneeInternational Engine Intellectual Property Company, LLC
InventorsMatthew Joseph Seiberlich, Michael James McNulty
Life of this patent
Estimating the term…
Abstract
An engine control system (32) apportions smoke and NOx in engine-out exhaust gas by a strategy (38) that corrects a target percentage for fresh air and a target percentage for exhaust gas to re-calculate a set-point for fresh air mass flow. The target percentage for fresh air mass flow is calculated as a function of engine speed (N) and an engine output torque request (TQI_DRIV).
Claims18
A compression ignition engine comprising:
- engine cylinders within which combustion of fuel occurs to operate the engine;
- an intake system for introducing fresh air into the engine cylinders;
- a fueling system for introducing fuel into the engine cylinders for combustion with the fresh air;
- an exhaust manifold into which the engine cylinders deliver exhaust gas created by combustion of fuel in the engine cylinders;
- an exhaust system for conveying exhaust gas from the exhaust manifold to atmosphere;
- an EGR system for diverting some of the exhaust gas coming from the exhaust manifold to mix with fresh air coming from the intake system and form an air/exhaust mixture that enters the engine cylinders through the intake manifold;
- and
- a control system for processing data to control certain aspects of engine operation and comprising a strategy:
- for calculating the difference between actual mass flow of the air/exhaust mixture that enters the engine cylinders and a set-point for fresh air mass flow calculated by the control system and then dividing the difference by the actual mass flow of the air/exhaust mixture that enters the engine cylinders to yield a target percentage for exhaust gas in the air/exhaust mixture while imposing both a maximum limit and a minimum limit on the target percentage for exhaust gas in the air/exhaust mixture;
- for dividing the multiplication product of an engine output torque request and a minimum air/fuel ratio that is a function of engine speed and the engine output torque request by the actual mass flow of the air/exhaust mixture that enters the engine cylinders to yield a target percentage for fresh air in the air/exhaust mixture;
- for correcting the target percentage for fresh air and the target percentage for exhaust gas to relatively apportion smoke and NOx in exhaust gas entering the exhaust system from the exhaust manifold as a function of the target percentage for fresh air and the target percentage for exhaust gas;
- and for using the corrected target percentage for fresh air to re-calculate the set-point for fresh air mass flow.
9 more elements
A method for apportioning smoke and NOx in engine-out exhaust gas from a compression ignition engine comprising:
- calculating the difference between actual mass flow of an air/exhaust mixture that enters the cylinders of the engine and a calculated set-point for fresh air mass flow into the cylinders and then dividing the difference by the actual mass flow of the air/exhaust mixture that enters the cylinders to yield a target percentage for exhaust gas in the air/exhaust mixture while imposing both a maximum limit and a minimum limit on the target percentage for exhaust gas in the air/exhaust mixture;
- dividing the multiplication product of an engine output torque request and a minimum air/fuel ratio that is a function of engine speed and the engine output torque request by the actual mass flow of the air/exhaust mixture that enters the cylinders to yield a target percentage for fresh air in the air/exhaust mixture;
- correcting the target percentage for fresh air and the target percentage for exhaust gas to relatively apportion smoke and NOx in engine-out exhaust gas as a function of the target percentage for fresh air and the target percentage for exhaust gas;
- and using the corrected target percentage for fresh air to re-calculate the set-point for fresh air mass flow.
1 more element
Dependencies are inferred from the claim text.