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US 8,036,813 B2Granted
EGR control system
AssigneeC.R.F. Societa Consortile per Azioni
InventorsMarco Tonetti, Enrico Lanfranco
Life of this patent
Estimating the term…
Abstract
In an internal-combustion engine with exhaust-gas-recirculation system, electronic control means are provided designed to process an analytical model of the quantities “effective lambda” and “effective EGR percentage”, which is constructed on the basis of the physical laws that regulate the fluid-dynamic conditions in the intake pipe, in the exhaust pipe, and in the recirculation pipe of the engine. On the basis of the deviation between the values of said quantities estimated by the model and the reference values of said quantities associated to the conditions of operation of the engine, an operation of correction on the control of the valve that governs the recirculation circuit is implemented.
Claims24
An internal-combustion engine comprising:
- a main air pipe;
- an intake pipe downstream of said main pipe which can be traversed by a gaseous mass greater than the amount that traverses said main pipe;
- at least one cylinder with at least one intake valve and at least one exhaust valve, which control, respectively, said intake pipe and an exhaust pipe;
- at least one recirculation pipe for exhaust-gas recirculation, controlled by a respective exhaust-gas recirculation valve, for supplying at least part of the exhaust gases that flow in the exhaust pipe again into the intake pipe, or, alternatively, means for obtaining the recirculation of the exhaust gases directly within the combustion chamber of the cylinder, with the aid of a system for variable actuation of the valves;
- a sensor of the airflow rate traversing said main pipe;
- first sensor means for detecting the operating conditions of the engine;
- second sensor means for detecting fluid-dynamic conditions in said intake and exhaust pipes;
- electronic control means designed to control said recirculation valve of said at least one recirculation pipe, or else said system for variable actuation of the valves, via an output signal, said electronic control means comprising a control block designed to process a first signal indicating the mass flow rate of exhaust gases recirculating in said at least one recirculation pipe, or else directly within the combustion chamber of the cylinder, on the basis of the measurement of said sensor of the airflow rate traversing said main pipe and of said first sensor means;
- said engine being characterized in that said electronic control means comprise a second control block (18) designed to attribute to at least one quantity representing the conditions of the gaseous mass circulating in said intake pipe a reference value of said quantity in steady-state conditions, on the basis of the data transmitted by said first sensor means and said second sensor means,
- said electronic control means moreover comprising a third correction block designed to process an analytical model of said quantity constituted by physical laws that regulate the fluid-dynamic conditions in one or more from among said intake pipe, said exhaust pipe, and said recirculation pipe, said analytical model generating, on the basis of the data transmitted by said first sensor means, said second sensor means, and said flow-rate sensor, an estimate of the real value of said quantity, wherein said correction block envisaging an
- operation of correction of the deviation between said reference value and said estimated value so that a second signal is produced indicating a corrective flow rate of exhaust gases, which, added to said first signal is able to generate an output signal of said electronic means that is such as to give rise to a corrected flow rate of exhaust gases recirculating within said at least one recirculation pipe, or else directly within the combustion chamber of the cylinder, to which there correspond equal values between said reference value and said estimated value.
8 more elements
A method for controlling the exhaust-gas-recirculation system in an internal-combustion engine of the type comprising:
- a main air pipe;
- an intake pipe downstream of said main pipe which can be traversed by a gaseous mass greater than the amount that traverses said main pipe;
- at least one cylinder with at least one intake valve and at least one exhaust valve that control, respectively, said intake pipe and an exhaust pipe;
- at least one recirculation pipe for exhaust-gas recirculation, controlled by a respective exhaust-gas recirculation valve, for supplying at least part of the exhaust gases that flow in the exhaust pipe again into the intake pipe, or, alternatively means for obtaining the recirculation of the exhaust gases directly within the combustion chamber of the cylinder, with the aid of a system for variable actuation of the valves;
- a sensor of the airflow rate traversing said main pipe;
- first sensor means for detecting the operating conditions of the cylinder;
- second sensor means for detecting fluid-dynamic conditions in said intake and exhaust pipes;
- electronic control means designed to control said recirculation valve of said at least one recirculation pipe, or else said system for variable actuation of the valves, via an output signal,
- in which the processing of a first signal is provided indicating the mass flow rate of recirculating exhaust gases in said at least one recirculation pipe, or else directly in the combustion chamber of the cylinder, on the basis of said first sensor means,
- said method being characterized in that it envisages control of at least one quantity representing the conditions of the gaseous mass circulating in said intake pipe,
- in which attributed to said quantity is a reference value of said quantity in steady-state conditions on the basis of the data transmitted by said first sensor means,
- and in which an analytical model of said quantity is processed that is constructed on physical laws that regulate the fluid-dynamic conditions in one or more from among said intake pipe, said exhaust pipe and said recirculation pipe, said analytical model generating, on the basis of the data transmitted by said first sensor means, said second sensor means, and said flow-rate sensor, an estimate of the real value of said quantity, and in which there is envisaged an operation of correction of the deviation between said reference value and said estimated value so that:
- a second signal is produced indicating a corrective mass flow rate of exhaust gases, which, added to said first signal, is able to generate an output signal that is such as to regulate a corrected flow rate of exhaust gases recirculating in said at least one recirculation pipe, or else directly in the combustion chamber of the cylinder, to which there correspond equal values between said reference value and said estimated value.
10 more elements
Dependencies are inferred from the claim text.