STRATEGY FOR CONTROL OF RECIRCULATED EXHAUST GAS TO NULL TURBOCHARGER BOOST ERROR
First Claim
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1. A method for coordinating control of exhaust gas recirculation from a exhaust system of a turbocharged internal combustion engine to an intake system of the engine with control of engine boost, the method comprising:
- developing data representing the mass flow rate of fresh air that is entering the intake system;
calculating data representing the mass flow rate of recirculated exhaust gas that is entraining with the fresh air entering the intake system by calculating data representing mass flow rate through the engine cylinders and calculating the difference between the data representing the calculated mass flow rate through the engine cylinders and the data representing the mass flow rate of fresh air entering the intake system;
calculating data representing expected mass flow rate through the engine cylinders that would occur if boost were equal to a desired set-point;
calculating data representing actual mass flow rate through the engine cylinders using actual boost;
calculating data representing the difference between the data representing actual mass flow rate through the engine cylinders and the data representing the expected mass flow rate through the engine cylinders; and
using the data representing the difference between the data representing actual mass flow rate through the engine cylinders and the data representing the expected mass flow rate through the engine cylinders as a feed-forward adjustment of the mass flow rate of recirculated exhaust gas in a direction of adjustment that seeks to null out the difference between desired boost set point and actual boost.
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Abstract
A method for coordinating control of exhaust gas recirculation (18) in a turbocharged internal combustion engine (10) with control of engine boost. When actual boost deviates from a desired boost set-point developed by a boost control strategy (32), such as during a sudden acceleration or deceleration, the EGR control strategy (34) provides a prompt adjustment of exhaust gas recirculation (EGR) seeking to null out the boost disparity.
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Citations
10 Claims
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1. A method for coordinating control of exhaust gas recirculation from a exhaust system of a turbocharged internal combustion engine to an intake system of the engine with control of engine boost, the method comprising:
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developing data representing the mass flow rate of fresh air that is entering the intake system; calculating data representing the mass flow rate of recirculated exhaust gas that is entraining with the fresh air entering the intake system by calculating data representing mass flow rate through the engine cylinders and calculating the difference between the data representing the calculated mass flow rate through the engine cylinders and the data representing the mass flow rate of fresh air entering the intake system; calculating data representing expected mass flow rate through the engine cylinders that would occur if boost were equal to a desired set-point; calculating data representing actual mass flow rate through the engine cylinders using actual boost; calculating data representing the difference between the data representing actual mass flow rate through the engine cylinders and the data representing the expected mass flow rate through the engine cylinders; and using the data representing the difference between the data representing actual mass flow rate through the engine cylinders and the data representing the expected mass flow rate through the engine cylinders as a feed-forward adjustment of the mass flow rate of recirculated exhaust gas in a direction of adjustment that seeks to null out the difference between desired boost set point and actual boost. - View Dependent Claims (2, 3, 4, 5)
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6. An engine system comprising:
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an engine having cylinders; a turbocharger; an intake system, including a compressor of the turbocharger, for delivering charge air to the engine cylinders; an exhaust system, including a turbine of the turbocharger, for conveying exhaust gas from the engine cylinders; an exhaust gas recirculation system, including an EGR valve, for recirculating exhaust gas from the exhaust system to the intake system; and a control system for coordinating control of exhaust gas recirculation comprising a processor for;
a) developing data representing the mass flow rate of fresh air that is entering the intake system, b) calculating data representing the mass flow rate of recirculated exhaust gas that is entraining with the fresh air entering the intake system by calculating data representing mass flow rate through the engine cylinders and calculating the difference between the data representing the calculated mass flow rate through the engine cylinders and the data representing the mass flow rate of fresh air entering the intake system, c) calculating data representing expected mass flow rate through the engine cylinders that would occur if boost were equal to a desired set-point, d) calculating data representing actual mass flow rate through the engine cylinders using actual boost, e) calculating data representing the difference between the data representing actual mass flow rate through the engine cylinders and the data representing the expected mass flow rate through the engine cylinders, andperforming feed-forward adjustment of the mass flow rate of recirculated exhaust gas in a direction of adjustment that seeks to null out the difference between desired boost set point and actual boost by processing the data representing the difference between the data representing actual mass flow rate through the engine cylinders and the data representing the expected mass flow rate through the engine cylinders to develop a feed-forward adjustment signal that is applied to the EGR valve to cause the adjustment. - View Dependent Claims (7, 8, 9, 10)
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Specification