Magneti Marelli S.p.a.

Magneti Marelli Powertrain, S.p.a.

Daniele Ceccarini

Luca Poggio

Matteo De Cesare

Marco Secco

Piero Maria Carbonaro

Andrea Gelmetti

Ciro Barberio

Eugenio Pisoni

Marco Berti

Marco Peretti

Alessandro Verdecchia

Chiaffredo Rinaudo

A method for estimating the sulfur content in the fuel of an internal combustion engine equipped with a catalyser capable of storing a quantity of sulfur and NOgroups. The method provides use of a current sulfur concentration value (S) and a correction of the current sulfur concentration value (S) in order to obtain a new sulfur concentration value (S). The method includes the steps of estimating a first value (NO) of the total quantity of NOgroups stored in the catalyser () by means of a model of NOgroup production by the engine, estimating a second value (NO) of the total quantity of NOgroups stored by the catalyser by means of a model of storage of the catalyser, and determining an additive correction coefficient (D) as the difference between the first estimated value (NO) and the second estimated value (NO).

Method for estimating the sulfur content in the fuel of an internal combustion engine

A method for estimating the sulfur content in the fuel of an internal combustion engine equipped with a catalyser, using a current sulfur concentration value (S) and a correction of said current sulfur concentration value (S) in order to obtain a new sulfur concentration value (S). The method includes the steps of measuring a first time interval (t-t) which is actually necessary in order to complete a regeneration process to remove sulfur; determining a quantity (SO) of sulfur stored in the catalyser before the regeneration process to remove sulfur using the current sulfur concentration value (S); estimating a second time interval (t-t) which is theoretically necessary to complete the regeneration process, on the basis of the estimated quantity (SO) of sulfur stored in the catalyser; and determining a multiplicative correction coefficient as a ratio between the first time interval (t-t) and the second time interval (t-t).

A method for estimating the sulfur content in the fuel of an internal combustion engine equipped with a catalyser; the percentage of sulfur present in the fuel supplied during a specific measurement time interval is estimated by dividing the quantity of sulfur stored in the catalyser during the measurement time interval by the product of a fixed conversion constant and the mass of fuel supplied to the cylinder in the measurement time interval.

A method for controlling the titre of the exhaust gases in an internal combustion engine. An oxygen sensor provides a signal indicative of a titre (lambda) of the exhaust gases. The method includes selecting respective values of operating parameters on the basis of an objective lambda value and engine-related parameters, calculating a correction parameter on the basis of the respective values of the operating parameters and the lambda signal and calculating an adjustment quantity of fuel on the basis of the correction parameter and a nominal quantity of fuel. The method further includes selecting respective values of a first and a second of the operating parameters, determining magnitudes as a function of the respective values of the first and the second operating parameters and determining a third of the operating parameters as a function of the first and the second operating parameters and a mean value of the correction parameter.

Method for controlling the titre of the exhaust gases in an internal combustion engine

A circuit for monitoring and diagnosing an oxygen probe provided with a sensitive cell connected between a first and a second signal terminal, and a heating member connected between a battery and a heating terminal; the circuit includes an interface stage and a control unit. The interface stage includes a first resistor connected between a switch which is normally open and a supply line at a known potential and the first signal terminal, a second resistor connected between the first signal terminal and a second signal terminal and a third resistor connected between the second signal terminal and reference potential line. The control unit further includes a first analog-digital converter connected to the first signal terminal and a second analog-digital converter connected to the second signal terminal.

Circuit and a method for monitoring and diagnosing an oxygen probe

A method is described for estimating the temperature of the exhaust gases upstream from a pre-catalyser disposed along an exhaust pipe of an internal-combustion engine, which is provided with a system for controlling the composition of the exhaust gases, comprising an oxygen sensor, which is disposed along the exhaust pipe, upstream from the pre-catalyser, a heater, which is associated with the oxygen sensor, and a control unit, which, inter alia, serves the purpose of piloting the heater. The method comprises the steps of: determining an operative quantity, which is correlated to an electrical power supplied to the heater, in order to keep the operative temperature of the oxygen sensor close to a target temperature; and determining the temperature of the exhaust gases upstream from the pre-catalyser, according to the said operative quantity.

Method for estimating the temperature of the exhaust gases upstream from a pre-catalyser, disposed along an exhaust pipe of an internal-combustion engine

A method for controlling the titre of the air-fuel mixture in an internal combustion engine provided with at least two cylinders, in which the exhaust gas present in a common exhaust manifold is analyzed in order to measure at least two successive values of the overall air-fuel ratio of the cylinders; a value of the air-fuel ratio of a final combusted cylinder being estimated by carrying out a linear composition of the two successive values of the overall air-fuel ratio of the cylinders and the value of the air-fuel ratio of the final combusted cylinder being attributed to a first of the cylinders and being used to correct a titer of the air-fuel mixture introduced into the first cylinder.

Method for controlling the titre of the air-fuel mixture in an internal combustion engine

A method for the diagnosis of an exhaust gas purification system for an internal combustion engine, provided with a pre-catalyst and a main catalyst disposed along an exhaust duct of an internal combustion engine; the method including the stages of determining a real heat supplied to the exhaust gases in the pre-catalyst as a function of a input temperature and an output temperature of the exhaust gases at the input and output respectively of the pre-catalyst; determining a nominal heat supplied during nominal operating conditions of the pre-catalyst; calculating an index representative of the state of wear of the pre-catalyst, as a function of the real heat and the nominal heat; comparing the index with a threshold value.

Method for the diagnosis of an exhaust gas purification system for an internal combustion engine

Control device for a linear oxygen sensor located in an exhaust pipe of an internal combustion engine in contact with exhaust gases in use, the control device including a linear oxygen sensor composed of at least one reference chamber for receiving a specified percentage of oxygen and being one of at least two types which differ in the way in which the at least one reference chamber receives oxygen; controller for exerting a control action on the linear oxygen sensor to generate an output signal (DIP) at an output representing a ratio of the exhaust gases and being composed of a programmable control device; and an operating unit for operating and programming the programmable control device to match the controller to the type of linear oxygen sensor to which it is connected.

Control device for a linear oxygen sensor

A self-adapting control method for an exhaust system for internal combustion engines with controlled ignition, including an engine, a pre-catalyst, a trap for the collection of nitrogen oxides having a maximum initial capacity and a maximum available capacity not greater than this maximum initial capacity and a linear oxygen sensor disposed downstream of the trap for the collection of nitrogen oxides and generating at least a downstream composition signal substantially proportional to a downstream oxygen titer. The method comprises the stages of carrying out at least one regeneration process and carrying out at least one desulphurisation process of the trap for the collection of nitrogen oxides and also the stage of estimating, at least after each regeneration process, the maximum available capacity as a function of the maximum initial capacity and the downstream composition signal.

Self-adapting control method for an exhaust system for internal combustion engines with controlled ignition

A method of controlling and diagnosing the heater of a sensor sensitive to the composition of the exhaust gas of an engine; the sensor having at least an electrolytic cell sensitive to oxygen ions, and supplying information relative to the ratio of the mixture supplied to the engine; the method including the steps of: calculating an internal resistance value of the cell on the basis of detected values of the voltage at the terminals of the cell before and after supplying a reference current to the cell; correcting the calculated internal resistance value as a function of the detected ratio of the mixture supplied to the engine; converting the corrected internal resistance value into a current temperature value of the sensor; feedback controlling the temperature of the sensor by regulating the current supplied to the heater by processing the deviation between the current temperature value and an objective temperature; and diagnosing the efficiency of the heater as of the corrected internal resistance value of the cell.

Method of controlling and diagnosing the heater of an engine exhaust gas composition sensor

The control arrangement comprises an oxygen linear test sensor located along the exhaust duct of an internal combustion engine, the sensor having a chamber able to receive part of the exhaust gas and two electrolytic cells of which one is electrically piloted; the arrangement having a retro-operation test circuit able to adjust the current piloted to the cell to give rise to an oxygen ions draining mechanism from and/or towards the chamber which induces the stoichiometric condition within the chamber itself, and an outlet circuit able to convert the piloted current into a first signal representative of nature of the mixture fed to the engine; the arrangement being provided with a memory circuit which memorises the value of a compensation resistance of the eventual spreads of the piloted current of a correcting circuit receiving the stored value of the compensation resistance and able to ensure a correction for the first signal to recover the spreads of piloted current to the cell; the correcting circuit providing an outlet signal effectively representative of the nature and independent of the variations in compensation resistance.

Oxygen linear sensor test arrangement

Method for controlling the strength of the air/fuel mixture supplied to an internal-combustion engine after the engine has been in a fuel cut-off operating condition during which a catalytic converter arranged along the exhaust pipe of the engine is acted on by a flow of air and stores oxygen; the method comprising the steps of measuring the strength of the mixture supplied to the engine by means of an oxygen sensor arranged along the exhaust pipe upstream of the catalytic converter; estimating the quantity of oxygen stored by the catalytic converter during the fuel cut-off condition on the basis of the measured strength; and, at the end of the fuel cut-off condition, correcting the strength of the mixture with respect to a target value in relation to the quantity of estimated oxygen, so as to ensure controlled enrichment of the mixture which allows rapid disposal of the oxygen stored by the catalytic converter; the correction of the strength allowing minimization of the time interval during which the catalytic converter operates at low efficiency at the end of the fuel cut-off condition.

Method for controlling the strength of the air/fuel mixture supplied to an internal-combustion engine

Control method for an oxygen linear sensor, in which the sensor is located along an exhaust duct of an internal combustion engine to receive into a separate chamber part of the exhaust gas and generate a first signal representative of the swing between the composition of the gases in the chamber and a reference stoichiometric composition; the first signal being processed by a retroactive circuit which pilots an electrical current Ip into the sensor in such a manner as to generate an oxygen ion draining mechanism from and towards the chamber and to cancel the swing; the current being converted into an output signal which saving an error due to current spreads, is proportional to the quantity of oxygen present in the exhaust gases; the method presenting the calculation phase of a correction parameter which is applied to the output signal to make it effectively proportional to the quantity of oxygen present in the exhaust gases; the calculation of the parameter being effected with the sensor located in a controlled atmosphere by means of processing of the output signal and of a nominal voltage defining the theoretical value of the output signal in the presence of the said controlled atmosphere.

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Rimini, Italy

Daniele Ceccarini