DE202014004965U1 - Electronic control unit for an internal combustion engine - Google Patents

Abstract

An electronic control unit (450) for an internal combustion engine (110) configured to cyclically: - control a value (ES (i)) of engine speed, - control a value (RT (i)) of engine requested torque, To determine a target value (SOI_T (i)) of an injection start on the basis of the engine speed value (ES (i)) and the value of the requested torque (RT (i)), the injection start target value (SOI_T (i)) thereto use to determine an injection start operating value (SOI_O (i)), - operate the engine (110) to perform a main injection using the injection start operating value (SOI_O (i)), the electronic control unit (450) configured to determine the start of injection operating value (SOI_O (i)) by: - checking whether a cylinder protection strategy is activated or deactivated, - equating the start of injection operating value (SOI_O (i)) with the start of injection Z iel value (SOI_T (i)) when the cylinder protection strategy is deactivated - the setting of the start of injection operating value (SOI_O (i)) as a smaller value of start of injection target value (SOI_T (i)) and a start of injection maximum value (SOI_Max (i)) which is calculated by adding a specified injection start increment (ΔSOI (i)) to the injection start operating value (SOI_O (i-1)) detected at the previous cycle when the cylinder protection strategy is activated.

Description

TECHNICAL AREA

The present invention generally relates to an electronic control unit (ECU) for controlling an internal combustion engine, such as a diesel engine or a gasoline engine. In particular, the present invention relates to a strategy provided to the electronic control unit to control the fuel injections of the internal combustion engine during release maneuvers.

STATE OF THE ART

It is known that an internal combustion engine of an automotive system conventionally includes an engine block having at least one cylinder. Each cylinder includes a piston which, cooperating with a cylinder head, defines a combustion chamber. In the combustion chamber, an air / fuel mixture is cyclically introduced and ignited, whereby rapidly expanding exhaust gases are generated, which trigger linear movements of the piston. The piston is coupled to a crankshaft via a connecting rod, which converts the linear movements of the piston into a rotation of the crankshaft.

The cylinder has at least two valves including an intake valve and an exhaust valve actuated by at least one camshaft that rotates in time with the crankshaft. The inlet valve serves to selectively introduce air into the combustion chamber. The air may be distributed into the intake valve via an intake manifold receiving the air from an intake passage in fluid communication with the environment. The exhaust valve serves to selectively exhaust the exhaust gases from the combustion chamber. The exhaust gas from the exhaust valve may be collected in an exhaust manifold that discharges the exhaust gases into the exhaust passage in fluid communication with the environment.

The internal combustion engine may also be equipped with a turbocharger which essentially comprises a compressor rotationally coupled to a turbine. The turbine is located in the exhaust passage and is rotated by the exhaust gases coming from the exhaust manifold. The compressor is located in the intake passage to increase the pressure of the air in the intake manifold.

The delivery of the fuel to the combustion chamber is generally by a fuel injector that may be in fluid communication with a fuel pipe.

Normally, a fuel pump is provided, which draws the fuel from a fuel tank and conveys under pressure into the fuel pipe. The fuel injector is essentially implemented as a type of electro-mechanical valve with a needle normally held in a closed position by a spring and an electromagnetic actuator (for example a solenoid) which selectively moves the needle to an open position in response to a field current emotional. In this way, a certain amount of fuel from the fuel pipe is introduced under pressure into the combustion chamber and thus triggered a so-called fuel injection pulse.

The excitation current is provided by an electronic control unit (ECU) generally configured to actuate the fuel injector to perform a plurality of injection pulses per engine cycle in accordance with a multiple injection scheme. The multiple injection scheme usually includes a main injection, which is generally performed immediately before top dead center (TDC) of the piston to maximize the torque generated at the crankshaft, and a plurality of small injections that occur prior to the main injection (e.g. Pilot injections or pilot injections) and / or after the main injection (eg as post-injections). Each of these injection pulses is determined by the electronic control unit by means of the determination of the start of injection (SOI), ie the moment in which the excitation current is to be applied to open the fuel injector, and the excitation time (ET), ie the time duration. during which the excitation current is applied to keep the fuel injector open, controlled.

With particular reference to the main injection, the electronic control unit is generally configured to determine the SOI based on engine speed and engine load. The engine speed is the rotational speed of the crankshaft and can be measured by means of a speed sensor and a position sensor associated therewith. The engine load may be defined as the torque required on the crankshaft and is linked to the position of an accelerator pedal. The actual values of these two key parameters are used as inputs to an SOI calibration panel, which gives as output a corresponding SOI value for the main injection. Conventionally, the main injection SOI is a parameter indicating the angular position of the crankshaft at the time of the start of the main injection. This parameter is expressed as the ignition angle with respect to the angular position of the crankshaft that corresponds to the top dead center of the piston. It follows that the main injection SOI is zero when the main injection is to start exactly when the piston is in TDC and that it is progressively increasing, as far as it is concerned the beginning of the injection with respect to the TDC must be anticipated. In general, the efficiency of fuel combustion, and thus the torque generated at the crankshaft, are greater at high values of main injection SOI (ie well before TDC), while decreasing at lower values of main injection SOI (closer to TDC).

In order to prevent any damage to the internal combustion engine, the maximum pressure in the combustion chamber must always be below a specified limit, which is generally dependent on the construction of the engine components, in particular their dimensions and the materials used. The maximum pressure in the combustion chamber is primarily dependent on the air pressure in the intake manifold when the intake valve opens before the start of the compression stroke of the piston and the expansion of the exhaust gases during fuel combustion prior to the exhaust valve opening.

As in the left part of 6 1, the internal pressure of the intake manifold (curve B) progressively increases under the influence of the turbocharger as the demanded engine torque increases towards a full load condition (curve A), for example because the driver is deeply depressing the accelerator pedal, causing the combustion chamber maximum pressure (curve C) to decrease ) to potentially exceed the pressure limit (line D). In order to prevent this side effect, in the prior art the main injection SOI (curve E) is simultaneously reduced (ie brought closer to the TDC) in order to reduce the efficiency of the fuel combustion and thus the pressure contribution due to the expansion of the exhaust gases. This SOI reduction is achieved by using injection calibrators, such as those in 7 1, wherein the requested engine torque exceeds a critical value (indicated by F) that is a limit between part loads and full or near full loads for the specific engine.

However, this strategy produces another side effect that occurs when, as explained above, starting from a full load or near full load condition, the demanded engine torque (curve A) abruptly decreases as in the right part of FIG 6 represented, for example, because the driver lets go of the gas pedal. Such release, in fact, causes an extremely rapid increase in the main injection SOI (curve E), accompanied by a rather slow decrease in intake manifold pressure (curve B). It follows that the internal combustion chamber pressure (curve C) reaches a peak value during the very first engine cycles after release, which far exceeds the pressure limit (curve D) and can have an extremely stressful effect on the engine components.

SUMMARY

An object of the present invention is to prevent an uncontrolled increase in combustor internal pressure that could exceed the corresponding pressure limit.

In particular, another object is to eliminate or at least positively reduce the pressure peak that normally occurs in the combustion chamber during release maneuvers from a full or near full load condition.

Another objective is to achieve these goals without compromising the performance and efficiency of the internal combustion engine under normal conditions.

These and other objects are achieved with the embodiments of the invention having the features described in the independent claims. In the dependent claims, secondary aspects of the invention are set forth.

• – Kontrolle eines Werts einer Motorgeschwindigkeit,
• – Kontrolle eines Werts eines vom Motor geforderten Drehmoments,
• – Bestimmen eines Einspritzbeginn-Zielwerts auf der Grundlage des Motorgeschwindigkeitswerts und des Werts des geforderten Drehmoments,
• – Anwenden des Einspritzbeginn-Zielwerts zur Bestimmung eines Einspritzbeginn-Betriebswerts,
• – Betätigen des Motors zur Ausführung einer Haupteinspritzung unter Anwendung des Einspritzbeginn-Betriebswerts,

wobei das elektronische Steuergerät für den Einspritzbeginn-Betriebswert konfiguriert wird durch:

• – die Prüfung, ob eine Zylinderschutzstrategie aktiviert oder deaktiviert ist,
• – die Gleichsetzung des Einspritzbeginn-Betriebswerts mit dem Einspritzbeginn-Zielwert, wenn die Zylinderschutzstrategie deaktiviert ist,
• – die Festlegung des Einspritzbeginn-Betriebswerts als kleineren Wert von Einspritzbeginn-Zielwert und einem Einspritzbeginn-Maximalwert, der durch die Hinzufügung eines festgelegten Einspritzbeginn-Inkrements zu dem beim vorangehenden Zyklus festgestellten Einspritzbeginn-Betriebswert berechnet wird, wenn die Zylinderschutzstrategie aktiviert ist.

Explained in more detail, an embodiment of the invention provides an electronic control unit for an internal combustion engine that is configured for the following cyclic activities:

• Control of a value of a motor speed,
• Control of a value of a torque required by the engine,
• Determining an injection start target value on the basis of the engine speed value and the value of the requested torque,
• Applying the start of injection target value for determining an injection start operating value,
• Actuating the engine to perform a main injection using the start of injection value,

wherein the start-of-injection electronic control unit is configured by:

• - checking whether a cylinder protection strategy is activated or deactivated,
• Equating the start of injection operating value with the start of injection target value when the cylinder protection strategy is deactivated,
• The determination of the start of injection operating value as a smaller value of start of injection target value and a start of injection maximum value, which is calculated by the addition of a specified start of injection increment to the injection start operating value established in the previous cycle when the cylinder protection strategy is activated.

When the cylinder protection strategy is deactivated, this solution determines the main injection SOI according to the conventional strategy to guarantee the performance and efficiency of the internal combustion engine under normal operating conditions. However, regardless of how fast the requested engine torque changes, if the cylinder protection strategy is activated, the main injection SOI can not increase faster than a set limit, thereby avoiding any uncontrolled increase in internal combustion chamber pressure.

According to one aspect of the invention, the electronic control unit may be configured to activate the cylinder protection strategies when the requested torque is greater than a predetermined critical value thereof and less than the requested torque observed in the previous cycle.

The effect of this aspect of the invention is that the cylinder protection strategy is activated only when the demanded engine torque actually decreases within a value bandwidth corresponding to high engine load conditions, for example, during a release maneuver, that is, from combustion chamber internal pressure for reasons inherent in In the introduction of this disclosure, an uncontrolled peak is expected.

In accordance with another aspect of the invention, the electronic controller may be configured to disable the engine protection strategy when the start of injection value corresponds to the start of injection target value.

Thanks to this solution, the cylinder protection strategy, once activated, remains active until the main injection SOI reaches the target value currently corresponding to the requested engine torque, thereby causing abrupt variations in the main injection SOI during the switching between the cylinder protection strategy and the default strategy be avoided.

• – Bestimmen eines maximalen Anstiegsgradienten für den Einspritzbeginn,
• – Multiplizieren des maximalen Einspritzbeginn-Anstiegsgradienten mit einem Zeitintervall, das seit dem vorangehenden Steuerzyklus verstrichen ist.

According to another aspect of the invention, the electronic control unit may be configured to determine the start of injection increment by the following measures:

• Determining a maximum increase gradient for the start of injection,
• Multiplying the maximum injection start increase gradient by a time interval elapsed from the previous control cycle.

This aspect of the invention means a simple and reliable solution for determining the main injection SOI increment in each control cycle while directly limiting the SOI rise gradient.

According to one aspect of the invention, the electronic control unit may be configured to determine the maximum injection startup increase gradient based on the engine speed value and the requested torque value.

In this way, it is possible to adjust, cycle by cycle, the threshold of the SOI slew rate based on the engine operating conditions.

• – die Nutzung des Motorgeschwindigkeitswerts und des Werts des geforderten Drehmoments zur Bestimmung eines nominalen Anstiegsgradienten,
• – die Berechnung eines Werts einer Ableitung des geforderten Motordrehmoments,
• – die Berechnung des maximalen Anstiegsgradienten durch Hinzufügen eines Korrektur-Addendums zum nominalen Anstiegsgradienten, wenn der Wert der geforderten Drehmoment-Ableitung (RTD(i)) positiv oder größer ist als der Wert der Ableitung des geforderten Motordrehmoments (RTD(i – 1)) im vorangehenden Zyklus,
• – die Gleichsetzung des maximalen Anstiegsgradienten mit dem nominalen Anstiegsgradienten, wenn der Wert der geforderten Drehmoment-Ableitung (RTD(i)) negativ und kleiner ist als der Wert der Ableitung des geforderten Motordrehmoments (RTD(i – 1)) im vorangehenden Zyklus.

According to another aspect of the invention, the electronic control unit may be configured to determine the maximum injection start increase gradient by:

• The use of the engine speed value and the value of the required torque to determine a nominal gradient of increase,
• The calculation of a value of a derivative of the required engine torque,
• The calculation of the maximum rise gradient by adding a correction addendum to the nominal increase gradient when the value of the requested torque derivative (RTD (i)) is positive or greater than the value of the derivative of the requested engine torque (RTD (i-1)) in the previous cycle,
• - equating the maximum gradient of rise with the nominal increase gradient when the value of the requested torque derivative (RTD (i)) is negative and less than the value of the derivative of the requested motor torque (RTD (i-1)) in the previous cycle.

This aspect of the invention has the effect that the main injection SOI can increase faster when the derivative of the requested engine torque is positive or at least increasing, namely, when the required engine torque does not abruptly decrease after being released. Having intervened with the cylinder protection strategy to prevent pressure spikes during the first post-release engine cycles, the cylinder protection strategy is accelerated to shorten its overall duration and quickly restore the standard strategy.

In accordance with another aspect of the invention, the electronic control unit may be configured to determine the nominal increase gradient by using the engine speed value and the requested torque value as inputs of a first calculation that gives as output a corresponding nominal slope gradient.

This aspect of the invention has the effect of providing a simple solution for determining the nominal increase gradient with little computational effort.

Another aspect of the invention contemplates that the electronic controller may be configured to determine the nominal increase gradient correction addend based on the value of the requested torque derivative, the engine speed value, and the requested torque value.

In this way, it is possible to adjust the correction addendum cycle by cycle based on the engine operating conditions.

• – die Verwendung des Motorgeschwindigkeitswerts und des Werts des geforderten Drehmoments als Eingang einer zweiten Kalkulierung, die als Ausgang einen entsprechenden Korrekturkoeffizienten ergibt,
• – die Verwendung des Werts der geforderten Drehmoment-Ableitung als Eingang einer dritten Kalkulierung, die als Ausgang einen weiteren Korrekturkoeffizienten ergibt,
• – die Berechnung des Korrektur-Addendums als Funktion beider Korrekturkoeffizienten.

According to another aspect of the invention, the electronic control unit may be configured to determine the correction addendum by:

• The use of the engine speed value and the value of the required torque as the input of a second calculation which gives as output a corresponding correction coefficient,
• The use of the value of the required torque derivative as input of a third calculation which gives as output a further correction coefficient,
• The calculation of the correction addendum as a function of both correction coefficients.

This aspect of the invention has the effect of providing a simple solution for determining the nominal slope gradient correction addendum with little computational effort.

• – Kontrolle eines Werts einer Motorgeschwindigkeit,
• – Kontrolle eines Werts eines vom Motor geforderten Drehmoments,
• – Bestimmen eines Einspritzbeginn-Zielwerts auf der Grundlage des Motorgeschwindigkeitswerts und des Werts des geforderten Drehmoments,
• – Verwenden des Einspritzbeginn-Zielwerts zur Bestimmung eines Einspritzbeginn-Betriebswerts,
• – Betätigen des Motors zur Ausführung einer Haupteinspritzung unter Anwendung des Einspritzbeginn-Betriebswerts,

wobei die Bestimmung des Einspritzbeginn-Betriebswerts folgende weitere Schritte umfasst:

• – die Prüfung, ob eine Zylinderschutzstrategie aktiviert oder deaktiviert ist,
• – die Gleichsetzung des Einspritzbeginn-Betriebswerts mit dem Einspritzbeginn-Zielwert, wenn die Zylinderschutzstrategie deaktiviert ist,
• – die Einstellung des Einspritzbeginn-Betriebswerts als kleineren Wert von Einspritzbeginn-Zielwert und einem Einspritzbeginn-Maximalwerts, der durch die Hinzufügung eines festgelegten Einspritzbeginn-Inkrements zu dem beim vorangehenden Zyklus festgestellten Einspritzbeginn-Betriebswert berechnet wird, wenn die Zylinderschutzstrategie aktiviert ist.

A further embodiment of the invention provides a method for controlling the operation of an internal combustion engine, which provides the cyclic repetition of the following steps:

• Control of a value of a motor speed,
• Control of a value of a torque required by the engine,
• Determining an injection start target value on the basis of the engine speed value and the value of the requested torque,
• Using the start of injection target value to determine an injection start operating value,
• Actuating the engine to perform a main injection using the start of injection value,

wherein the determination of the start of injection value comprises the following further steps:

• - checking whether a cylinder protection strategy is activated or deactivated,
• Equating the start of injection operating value with the start of injection target value when the cylinder protection strategy is deactivated,
• Setting the injection start operation value as a smaller value of start of injection target value and a start of injection maximum value calculated by adding a specified start of injection increment to the injection start operating value detected in the previous cycle when the cylinder protection strategy is activated.

This embodiment of the invention basically has the same effects as the above-disclosed electronic control apparatus, particularly those of preventing uncontrolled and excessive pressure rise in the combustion chamber (s) of the internal combustion engine.

According to one aspect of the invention, the method may include the step of activating the cylinder protection strategy when the value of the requested torque is greater than a predetermined critical value thereof and less than the value of the required torque observed in the previous control cycle.

The effect of this aspect of the invention is that the cylinder protection strategy is activated only when the required engine torque actually decreases within a range of values that corresponds to high engine load conditions.

According to another aspect of the invention, the method may include the step of disabling the engine protection strategy when the start of injection value is equal to the start of injection target value.

Thanks to this solution, once the cylinder protection strategy has been activated, it remains active until the main injection SOI reaches the target value that currently corresponds to the required engine torque.

• – Bestimmen eines maximalen Anstiegsgradienten für den Einspritzbeginn,
• – Multiplizieren des maximalen Einspritzbeginn-Anstiegsgradienten mit einem Zeitintervall, das seit dem vorangehenden Steuerzyklus verstrichen ist.

According to another aspect of the invention, the determination of the start of injection increment may comprise the following further steps:

• Determining a maximum increase gradient for the start of injection,
• Multiplying the maximum injection start increase gradient by a time interval elapsed from the previous control cycle.

This aspect of the invention allows a direct limitation of the SOI rise gradient.

According to one aspect of the invention, the maximum injection start gradient may be determined based on the engine speed value and the requested torque value.

In this way, the SOI slew rate limit may be adjusted cycle by cycle based on engine operating conditions.

• – Verwendung des Motorgeschwindigkeitswerts und des Werts des geforderten Drehmoments zur Bestimmung eines nominalen Anstiegsgradienten,
• – Berechnen eines Werts einer Ableitung des geforderten Motordrehmoments,
• – Berechnen des maximalen Anstiegsgradienten durch Hinzufügen eines Korrektur-Addendums zum nominalen Anstiegsgradienten, wenn der Wert der geforderten Drehmoment-Ableitung positiv oder größer ist als der Wert der Ableitung des geforderten Motordrehmoments im vorangehenden Zyklus,
• – Gleichsetzen des maximalen Anstiegsgradienten mit dem nominalen Anstiegsgradienten, wenn der Wert der geforderten Drehmoment-Ableitung (RTD(i)) negativ und kleiner ist als der Wert der Ableitung des geforderten Motordrehmoments (RTD(i – 1)) im vorangehenden Zyklus.

According to another aspect of the invention, the determination of the maximum injection start increase gradient may further comprise the steps of:

• Use of the engine speed value and the value of the requested torque to determine a nominal gradient of increase,
• Calculating a value of a derivative of the required engine torque,
• Calculating the maximum increase gradient by adding a correction addendum to the nominal increase gradient if the value of the requested torque derivative is positive or greater than the value of the derivative of the required engine torque in the preceding cycle,
• - equating the maximum gradient of rise with the nominal increase gradient, if the value of the requested torque derivative (RTD (i)) is negative and less than the value of the derivative of the requested motor torque (RTD (i-1)) in the previous cycle.

This aspect of the invention has the effect that the main injection SOI can increase faster when the derivative of the requested engine torque is positive or at least increasing, namely, when the required engine torque does not abruptly decrease after being released.

In accordance with another aspect of the invention, the nominal slope gradient may be determined using the engine speed value and the requested torque value as inputs of a first calculation that gives as output a corresponding nominal slope gradient.

This aspect of the invention has the effect of providing a simple solution for determining the nominal increase gradient with little computational effort.

A further aspect of the invention provides that the nominal slope gradient correction addendum may be determined based on the value of the requested torque derivative, the engine speed value, and the requested torque value.

In this way, the correction addendum may be adjusted cycle by cycle based on the engine operating conditions.

• – Verwendung des Motorgeschwindigkeitswerts und des Werts des geforderten Drehmoments als Eingang einer zweiten Kalkulierung, die als Ausgang einen entsprechenden Korrekturkoeffizienten ergibt,
• – Verwendung des Werts der geforderten Drehmoment-Ableitung als Eingang einer dritten Kalkulierung, die als Ausgang einen weiteren Korrekturkoeffizienten ergibt,
• – Berechnen des Korrektur-Addendums als Funktion beider Korrekturkoeffizienten.

According to another aspect of the invention, the determination of the correction addendum may further comprise the steps of:

• Use of the engine speed value and the value of the required torque as input of a second calculation, which gives as output a corresponding correction coefficient,
• Use of the value of the required torque derivative as input of a third calculation, which gives as output a further correction coefficient,
• Calculate the correction addendum as a function of both correction coefficients.

This aspect of the invention has the effect of providing a simple solution for determining the nominal slope gradient correction addendum with little computational effort.

The method according to all embodiments of the invention may be performed by means of a computer program comprising a program code for performing all the steps of the method described above, and in the form of a computer program product comprising the computer program. The method may also be implemented as an electromagnetic signal, wherein the signal is modulated to carry a data bit sequence representing a computer program for performing all steps of the method.

• – Mittel zur Kontrolle eines Werts einer Motorgeschwindigkeitswerts,
• – Mittel zur Kontrolle eines Werts eines vom Motor geforderten Drehmoments,
• – Mittel zur Bestimmung eines Zielwert eines Einspritzbeginns auf der Grundlage des Motorgeschwindigkeitswerts und des Werts des geforderten Drehmoments,
• – Mittel zur Verwendung des Einspritzbeginn-Zielwerts zur Bestimmung eines Einspritzbeginn-Betriebswerts,
• – Mittel zum Betrieb des Motors zur Durchführung einer Haupteinspritzung unter Verwendung des Einspritzbeginn-Betriebswerts,

wobei die Mittel zur Bestimmung des Einspritzbeginn-Betriebswerts Folgendes umfassen:

• – Mittel zur Prüfung, ob eine Zylinderschutzstrategie aktiviert oder deaktiviert ist,
• – Mittel zur Gleichsetzung des Einspritzbeginn-Betriebswerts mit dem Einspritzbeginn-Zielwert, wenn die Zylinderschutzstrategie deaktiviert ist,
• – Mittel zur Festlegung des Einspritzbeginn-Betriebswert als kleineren Wert von Einspritzbeginn-Zielwert und einem Einspritzbeginn-Maximalwert, der durch Hinzufügen eines festgelegten Einspritzbeginn-Inkrements zu dem im vorangehenden Zyklus bestimmten Einspritzbeginn-Betriebswert berechnet wird, wenn die Zylinderschutzstrategie aktiviert ist.

A further embodiment of the invention provides an apparatus for controlling the operation of an internal combustion engine, comprising the following cyclically operating means:

• Means for controlling a value of a motor speed value,
• Means for controlling a value of a torque required by the engine,
• Means for determining a target value of an injection start on the basis of the engine speed value and the value of the requested torque,
• Means for using the start of injection target value for determining an injection start operating value,
• Means for operating the engine to perform a main injection using the injection start operating value,

wherein the means for determining the start of injection value comprises:

• Means for checking whether a cylinder protection strategy is activated or deactivated,
• Means for equating the start of injection operating value with the start of injection target value when the cylinder protection strategy is deactivated,
• - means for determining the start of injection operating value as a smaller value of start of injection target value and a start of injection maximum value, which is calculated by adding a specified start of injection increment to the determined in the previous cycle injection start operating value when the cylinder protection strategy is activated.

This embodiment of the invention basically has the same effects of the electronic control device disclosed above, particularly those of avoiding uncontrolled and excessive pressure rise in the combustion chamber (s) of the internal combustion engine.

According to one aspect of the invention, the device may include means for activating the cylinder protection strategy when the value of the requested torque is greater than a predetermined critical value thereof and less than the value of the required torque observed in the previous control cycle.

The effect of this aspect of the invention is that the cylinder protection strategy is activated only when the requested engine torque actually decreases within a value bandwidth that corresponds to high engine load conditions.

According to a further aspect of the invention, the device may comprise means for deactivating the engine protection strategy when the start of injection operating value is equal to the start of injection target value.

Thanks to this solution, once the cylinder protection strategy has been activated, it remains active until the main injection SOI reaches the target value that currently corresponds to the required engine torque.

• – Mittel zur Bestimmung eines maximalen Anstiegsgradienten für den Einspritzbeginn,
• – Mittel zum Multiplizieren des maximalen Anstiegsgradienten des Einspritzbeginns mit einem Zeitintervall, das seit dem vorangehenden Steuerzyklus verstrichen ist.

According to another aspect of the invention, the means for determining the start of injection increment may include:

• Means for determining a maximum increase gradient for the start of injection,
• - Means for multiplying the maximum increase gradient of the start of injection with a time interval that has elapsed since the previous control cycle.

This aspect of the invention allows a direct limitation of the SOI rise gradient.

According to one aspect of the invention, the maximum injection start slope gradient determination means may be configured to perform its task based on the engine speed value and the requested torque value.

In this way, the SOI slew rate limit may be adjusted cycle by cycle based on engine operating conditions.

• – Mittel zur Verwendung des Motorgeschwindigkeitswerts und des Werts des geforderten Drehmoments zur Bestimmung eines nominalen Anstiegsgradienten,
• – Mittel zum berechnen eines Werts einer Ableitung des geforderten Motordrehmoments,
• – Mittel zum Berechnen des maximalen Anstiegsgradienten durch Hinzufügen eines Korrektur-Addendums zum nominalen Anstiegsgradienten, wenn der Wert der geforderten Drehmoment-Ableitung (RTD(i)) positiv oder größer ist als der Wert der Ableitung des geforderten Motordrehmoments (RTD(i – 1)) im vorangehenden Zyklus,
• – Mittel zur Gleichsetzung des maximalen Anstiegsgradienten mit dem nominalen Anstiegsgradienten, wenn der Wert der geforderten Drehmoment-Ableitung (RTD(i)) negativ und kleiner ist als der Wert der Ableitung des geforderten Motordrehmoments (RTD(i – 1)) im vorangehenden Zyklus.

According to a further aspect of the invention, the means for determining the maximum injection start increase gradient may comprise:

• Means for using the engine speed value and the value of the requested torque to determine a nominal gradient of increase,
• Means for calculating a value of a derivative of the required engine torque,
• - means for calculating the maximum rise gradient by adding a correction addendum to the nominal rise gradient when the value of the requested torque derivative (RTD (i)) is positive or greater than the value of the derivative of the requested engine torque (RTD (i-1) ) in the previous cycle,
• - means for equalizing the maximum gradient of rise with the nominal increase gradient, when the value of the requested torque derivative (RTD (i)) is negative and less than the value of the derivation of the required engine torque (RTD (i-1)) in the previous cycle.

This aspect of the invention has the effect that the main injection SOI can increase faster when the derivative of the requested engine torque is positive or at least increasing, namely, when the required engine torque does not abruptly decrease after being released.

According to a further aspect of the invention, the means for determining the nominal increase gradient may comprise means for using the engine speed value and the value of the requested torque as inputs of a first calculation which gives as output a corresponding nominal gradient of increase.

This aspect of the invention has the effect of providing a simple solution for determining the nominal increase gradient with little computational effort.

A further aspect of the invention provides that the means for determining the nominal rise gradient correction addendum can be configured to perform its task on the Satisfy the basis of the value of the requested torque derivative, the engine speed value and the value of the requested torque.

In this way, the correction addendum may be adjusted cycle by cycle based on the engine operating conditions.

• – Mittel zur Verwendung des Motorgeschwindigkeitswerts und des Werts des geforderten Drehmoments als Eingang einer zweiten Kalkulierung, die als Ausgang einen entsprechenden Korrekturkoeffizienten ergibt,
• – Mittel zur Verwendung des Werts der geforderten Drehmoment-Ableitung als Eingang einer dritten Kalkulierung, die als Ausgang einen weiteren Korrekturkoeffizienten ergibt,
• – Mittel zum Berechnen des Korrektur-Addendums als Funktion beider Korrekturkoeffizienten.

According to another aspect of the invention, the means for determining the correction addendum may further comprise:

• Means for using the engine speed value and the value of the required torque as the input of a second calculation which gives as output a corresponding correction coefficient,
• Means for using the value of the required torque derivative as the input of a third calculation which gives as output a further correction coefficient,
• - means for calculating the correction addendum as a function of both correction coefficients.

This aspect of the invention has the effect of providing a simple solution for determining the nominal slope gradient correction addendum with little computational effort.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described by way of example with reference to the accompanying drawings.

1 is a schematic representation of an automotive system according to an embodiment of the invention.

2 FIG. 12 is a cross-sectional view AA of an automobile system of FIG 1 belonging internal combustion engine.

3 FIG. 10 is a flowchart illustrating a control cycle according to an embodiment of the invention. FIG.

4 is a flowchart in which one in the control cycle of 3 contained subroutine is shown.

5 FIG. 15 is a graph showing the changes in the time required engine torque, the main injection SOI, and the internal combustion chamber pressure changes in accordance with the control cycle of FIG 3 powered engine off 2 during a release maneuver from a full load condition.

6 is the diagram of 5 for the internal combustion engine operated with a standard strategy.

7 shows an example of an SOI calibration board.

8th FIG. 14 is a graph illustrating the changes over time of the requested engine torque and its derivative during a release-off maneuver from a full load condition. FIG.

9 FIG. 15 is a graph showing the changes over time of the requested engine torque, the required engine torque dissipation, and the main injection SOI for the engine of the engine 2 , according to the 10 modified control cycle is operated during a release condition based on a full load condition maneuver.

10 is a flowchart of a modified part of the control cycle of 3 ,

DETAILED DESCRIPTION

Some embodiments may be an automotive system 100 include that in the 1 and 2 is shown, and that an internal combustion engine (ICE) 110 with an engine block 120 owns at least one cylinder 125 with a piston 140 defined, wherein the piston 140 having a coupling with which the crankshaft 145 is turned. A cylinder head 130 works with the piston 140 together around a combustion chamber 150 define. An air-fuel mixture (not shown) is placed in the combustion chamber 150 introduced and ignited, resulting in hot expanding combustion gases, leading to a reciprocation of the piston 140 to lead. The fuel is from at least one fuel injector 160 provided and the air through at least one inlet 210 , The fuel is under high pressure from a fuel pipe 170 , the fluid zueitend with a high-pressure pump 180 that the pressure of a fuel source 190 increased fuel, is connected to the inlet 210 guided. Each of the cylinders 125 has at least two valves 215 coming from a camshaft 135 operated at the same time as the crankshaft 145 rotates. The valves 215 selectively release air from the inlet 210 into the combustion chamber 150 and alternately allow the outlet of the exhaust gases through the outlet 220 , In some embodiments, a camshaft phasing system 155 used to selectively the timing between the camshaft 135 and the crankshaft 145 to change.

The air can be the air inlets 210 via an intake manifold 200 be supplied. A line 205 leads the intake manifold 200 Ambient air too. In other embodiments, a throttle 330 be selected to control the air flow to the intake manifold 200 to regulate. In other embodiments, a compressed air system such as a turbocharger is used 230 with a compressor 240 used together with a turbine, used. The rotation of the compressor 240 increases the pressure and the temperature of the air in the pipe 205 and the intake manifold 200 , One in the lead 205 containing intercooler 260 can reduce the temperature of the air. The turbine 250 turns when flowing from an exhaust manifold 225 coming exhaust gases, the exhaust gas from the outlet 220 passes through a series of vanes before passing through the turbine 250 is expanded. The exhaust gases leave the turbine 250 and become an exhaust system 270 guided. This example shows a variable geometry turbine (VGT) with a VGT actuator 290 formed to move the vanes to allow the vanes to flow the exhaust gas through the turbine 250 to change. In other embodiments, the turbocharger 230 have a fixed geometry and / or have a wastegate.

The exhaust system 270 can be an exhaust pipe 275 comprising one or more exhaust aftertreatment devices 280 Has. Exhaust aftertreatment systems may be any devices that allow the composition of the exhaust gases to be changed. Some examples of exhaust aftertreatment systems include catalytic (two- and three-way) converters, oxidation catalysts, lean NOx traps, hydrocarbon adsorbers, selective catalytic reduction (SCR) systems, and particulate filters. Other embodiments include an exhaust gas recirculation (EGR) system. 300 that with the exhaust manifold 225 and the intake manifold 200 connected is. The EGR 300 can be an EGR cooler 310 indicate the temperature of the exhaust gases in the EGR 300 to reduce. An EGR valve 320 regulates the flow of exhaust gases in the EGR system 300 ,

The automobile system 100 can still use an electronic control unit (ECM) 450 configured to receive signals from or to various, with the ICE 100 to send or receive connected devices. The ECM 450 can input signals from different, with the ICE 110 receive coupled sensors, such as a mass flow and temperature sensor 340 , a pressure and temperature sensor 350 for the manifold, a sensor 360 for the pressure in the combustion chamber, sensors 380 for the coolant and oil temperature and / or the associated fill level, a pressure sensor 400 for the fuel, a camshaft position sensor 410 , a crankshaft position sensor 420 , Sensors 430 for the pressure and the temperature of the exhaust gases, an EGR temperature sensor 440 as well as a position sensor 445 for the gas pedal. Furthermore, the ECU 450 to output various signals to control the operation of the ICE 110 to control, for example, to fuel injectors 160 , to the throttle 330 , to the EGR valve 320 , to the VGT actuator 290 and to the camshaft adjusting system 155 , It should be noted that dashed lines are used to indicate various connections between the various sensors, devices and the ECM 450 but others have been omitted for purposes of clarity.

The control unit 450 may have a digital microprocessor unit (CPU) data-connected to a memory system and a bus system. The CPU is adapted to execute instructions executed as a program stored in a memory system, to detect input signals from the data bus, and to output signals to the data bus. The storage system may have various storage media such as optical, magnetic, solid state and other non-volatile media. The program may be arranged to be capable of embodying the methods described herein so that the CPU may perform the steps of such methods, and hence the ICE 110 can control.

The stored program in the storage medium is the control unit from the outside wired or supplied by radio. Outside the automobile system 100 it occurs regularly on a computer program product, which is also referred to as a computer or machine readable medium, and which is to be understood as a computer program code on a carrier. The wearer may be volatile or non-volatile with the result that one can also speak of a volatile or non-volatile nature of the computer program product.

An example of a volatile computer program product is a signal, e.g. B. an electromagnetic signal such as an optical signal, which is a carrier for the computer program code. The carrying of the computer program code may be achieved by modulating the signal with a conventional modulation technique such as QPSK for digital data so that binary data representing the computer program code is impressed on the volatile electromagnetic signal. Such signals are used, for example, when a computer program code is wirelessly transmitted to a laptop over a WiFi connection.

In the case of a non-transitory computer program product, computer program code is embodied in a substrate-bound storage medium. The storage medium is then the one above said non-volatile carrier, so that the computer program code permanently or permanently stored in or on the storage medium. The storage medium may be of a conventional type, as known in the computer technology field, for example a flash memory, an asic, a CD and the like.

Instead of an engine control unit 450 can the automobile system 100 have a different type of processor to provide the electronic logic, such as an embedded controller, an on-board computer, or any other type of processor that can be used in a vehicle.

One of the main tasks of the ECU 450 consists in the operation of the fuel injectors 160 , Every fuel injector 160 is basically designed as an electromechanical valve with a needle normally held by a spring and an electromagnetic actuator (for example a solenoid) in a closed position which selectively moves the needle to an open position in response to an excitation current, and thus a so-called Injection pulse triggers. The excitation current is supplied by the ECU 450 provided generally configured to the fuel injector 160 to operate to perform a plurality of injection pulses per engine cycle in accordance with a multiple injection scheme. The multiple injection scheme usually includes a main injection, which is primarily responsible for that at the crankshaft 145 generated torque, and several small injections that are performed before the main injection (pilot injections or pilot injections) and / or after the main injection (post-injections). Each of these injection pulses is generally from the ECU 450 by means of the determination of the start of injection (SOI), ie the moment in which the excitation current is to be applied for opening the fuel injector, and the injection time (ET), ie the time duration during which the excitation current is applied, about the fuel injector 160 to keep it open.

With particular reference to the main injection, the ECU 450 be configured to use the main injection SOI by means of the in 3 shown control cycle during the operation of the ICE 110 is repeated periodically. The time period between each repetition of the control cycle can be extremely short, for example, at an interval between 5 and 15 milliseconds.

The main injection SOI can be expressed as an ignition angle with respect to the angular position of the crankshaft, that of the top dead center position of the piston 140 equivalent. This implies that the main injection SOI is zero when the main injection must start just when the piston is at the TDC and progressively increases as far as the beginning of the injection with respect to the TDC needs to be anticipated.

In very general terms, the control cycle causes the ECU 450 to determine an operating value SOI_O (i) for the main injection SOI and then the injector 160 of the internal combustion engine 110 to perform a main injection using the operating value SOI_O (i).

In more detail, the control cycle causes the ECU 450 in addition, a value ES (i) of the engine speed and a value RT (i) of the ICE 110 required torque to determine the operating value SOI_O (i). The engine speed is the rotational speed of the crankshaft 145 , so that the value ES (i) with the position sensor 420 can be measured. The value ET (i) of the requested torque may be based on the position of the accelerator pedal 446 be determined by the accelerator pedal position sensor 445 can be controlled.

The values RT (i) and ES (i) are determined by the ECU 450 as inputs to an SOI calibration board 600 which gives as output a corresponding target value SOI_T (i) of the main injection SOI. The SOI calibration board 610 can from the in 7 of the type shown, which comprises a plurality of curves, each corresponding to a specific engine speed value or level, each of these curves correlating a value of the requested torque with an associated value of the main injection SOI. The SOI calibration board 600 can be determined by experimental measures taken on a test engine of exactly the same type as the engine 110 and then in the storage system 460 be filed.

At the same time, the control cycle causes the ECU 450 to check if a cylinder protection strategy is enabled or disabled (block 605 ), for example, whether a marker representative of the cylinder protection strategy is currently enabled or disabled. When the cylinder protection strategy is disabled (Block 610 ), the operating value SOI_O (i) for the main injection SOI is set equal to the target value SOI_T (i). Conversely, when the cylinder protection strategy is activated, the operating value SOI_O for the main injection SOI becomes equal to the output SOI_M (i) of a gradient limiter 615 set.

The gradient limiter 615 receives as inputs the target value SOI_T (i) and a maximum increase gradient MRG (i) for the main injection SOI. The maximum gradient of gradient MRG (i), at which may be a monotonically increasing function, may be provided by the ECU 450 on the basis of the motor speed value ES (i) and the value RT (i) of the required torque. In particular, these two values may be inputs to a gradient calibration board 620 are used, which gives as output a corresponding maximum increase gradient MRG (i). The gradient calibration board 620 can in the storage system 460 be filed.

The gradient calibration board 620 can be determined by experimental measures taken on a test engine of exactly the same type as the engine 110 be made. During these experiments, the test engine may be operated to produce abrupt increases in main injection SOI under varying conditions of engine speed and torque demand while measuring the pressure in the combustion chamber. In this way, for each pair of engine speed value and requested torque values, the maximum slope gradient of the SOI may be determined which does not cause the combustion chamber pressure to exceed a predetermined pressure limit (such as that indicated by line D in FIG 6 displayed), thereby avoiding excessive loading of the cylinder and / or other engine components.

Upon receipt of the target value SOI_T (i) and a maximum increase gradient MRG (i), the gradient limiter sets 615 in the current control cycle i, an output value SOI_M (i) which may change with respect to the output value SOI_M (i-1) in the preceding cycle i-1, but not faster than the set maximum increase gradient MRG (i).

wobei gilt: SOI_T(i) ist der Zielwert des im aktuellen Steuerzyklus i als Eingang empfangenen SOI, SOI_M(i – 1) ist der Ausgang des Gradientenbegrenzers 615 im vorangehenden Steuerzyklus i – 1, und Δt ist die Zeit, die seit vom vorangehenden Steuerzyklus i – 1 bis zum aktuellen Steuerzyklus i verstrichen ist. Es ist zu beachten, dass aufgrund der Tatsache, dass der Gradientenbegrenzer 615 nur dann verwendet wird, wenn der Zylinderschutz aktiviert worden ist, der Ausgang SOI_M(i – 1) mit dem SOI-Betriebswert SOI_O(i – 1), der für den vorangehenden Steuerzyklus i – 1 bestimmt wurde, zusammenfällt.As an example, the gradient limiter 615 calculate a required slope gradient RRG (i) using the following equation:

where: SOI_T (i) is the target value of the SOI received as input in the current control cycle i, SOI_M (i-1) is the output of the gradient limiter 615 in the preceding control cycle i-1, and Δt is the time elapsed from the previous control cycle i-1 to the current control cycle i. It should be noted that due to the fact that the gradient limiter 615 is used only when the cylinder protection has been activated, the output SOI_M (i-1) coincides with the SOI operating value SOI_O (i-1) determined for the preceding control cycle i-1.

If the required increase gradient RRG (i) is less than the maximum increase gradient MRG (i), the output SOI_M (i) is set equal to the target value SOI_T (i). Conversely, if the required slope gradient RRG (i) is greater than the maximum slope gradient MRG (i), the output SOI_M (i) is calculated using the following equation: SOI_M (i) = SOI_Max (i) = ΔSOI (i) + SOI_M (i-1) where: SOI_Max (i) is a start of injection maximum value for the current control cycle i, SOI_M (i-1) is the output of the gradient limiter 615 in the preceding control cycle i-1, and ΔSOI (i) is a fixed SOI increment, which can be calculated from the following equation: ΔSOI (i) = MRG (i) · Δt

In fact, the output SOI_M (i) is the gradient limiter 615 the smaller value of injection start target value SOI_T (i) and injection start maximum value SOI_Max (i) for the current control cycle.

What now the activation / deactivation block 605 concerns, the control cycle may be the ECU 450 cause the cylinder protection strategies according to the in 4 to enable / disable the illustrated subroutine. This subroutine causes the ECU 450 to check whether the requested torque actually decreases, for example, by checking whether the current value RT (i) of the requested torque is smaller than the value RT (i-1) in the preceding control cycle. The subroutine causes the ECU 450 Further, to check whether the required torque is within a critical range, for example, by checking whether the current value RT (i) of the required torque exceeds a specified critical value RT_C. Specifically, the critical range may be defined as the range corresponding to full or almost full load conditions, and accordingly, the critical torque value ET_C of the requested torque may be the same as in 7 value corresponding to F, namely the value beyond which the SOI calibration curves for the ICE 110 lose weight. If both tests are positive (Block 625 ), the subroutine causes the activation of the protection strategy (Block 630 ) and the unrestricted maintenance of this activation (thanks to block 635 ).

Every time the required torque falls into the critical range, for example because the driver is accelerating 446 Thus, the cylinder protection strategy is immediately activated, thereby limiting the rate of increase of the main injection SOI and thus uncontrolled and excessive increases in the pressure in the combustion chamber 150 of the internal combustion engine 110 be avoided.

This effect can be compared by comparing 5 and 6 where it can be seen that the SOI (curve E) controlled by the cylinder protection strategy increases significantly more slowly during an abrupt reduction of the required engine torque as a result of the release (curve A) than with the standard strategy (FIG. 6 ) controlled SOI, whereby the peak value of the combustion chamber internal pressure (curve C) is eliminated.

After the cylinder protection strategy has been activated, the subroutine causes deactivation of the cylinder protection strategy (block 630 ) only if the operating value SOI_O (i) for the main injection SOI during a subsequent control cycle is equal to the target value SOI_T (i) thereof (block 640 ).

In this way, the cylinder protection strategy is kept active until the SOI has stopped increasing, thereby preventing the deactivation of the cylinder protection strategy from causing abrupt variations in the main injection SOI.

After deactivation, the cylinder protection strategy of Block 635 held inactive until another activation condition is detected, as discussed above.

It may be desirable in this context that the cylinder protection strategy remain activated for as short a time as possible in order to maximize the performance and efficiency of the ICE 110 not too bad. For this reason, with the cylinder protection strategy still active, the control strategy may be the ECU 450 cause the increase in main injection SOI to accelerate when the requested engine torque no longer abruptly decreases, for example, at the end of the release maneuver. To determine this condition, the derivative of the required torque can be used. How out 8th to see, the required torque derivative (curve G) has a minimum Q, when the falling ramp (curve A) of the required torque is almost over.

Based on this observation, the control cycle can be as well as in 10 4, wherein the only differences concern the determination of the maximum increase gradient MRG (i) for the main injection SOI. In this case, the control cycle causes the ECU 450 in general, to calculate the maximum increase gradient MRG (i) as the sum of a nominal increase gradient NRG (i) and a correction addendum CA (i) thereof (Block 645 ).

The nominal increase gradient NRG (i), which may be a monotonically increasing function, may be derived from the ECU 450 on the basis of the motor speed value ES (i) and the value RT (i) of the required torque. In particular, these two values may be inputs to a gradient calibration board 650 which gives as output a corresponding nominal increase gradient MRG (i). The gradient calibration board 650 can in the storage system 460 can be stored and can be the same board that in 3 with the sign 620 is marked.

At the same time, the control cycle causes the ECU 450 for calculating a current value RTD (i) of the required torque derivative. The required torque derivative RTD (i) can be filtered to remove noise. If the value RTD (i) of the requested torque derivative, calculated in the current control cycle i, is greater than the value RTD (i-1) of the requested torque derivative calculated in the preceding control cycle i-1 (blocks 655 . 660 and 665 ), or when the value RTD (i) of the requested torque derivative is positive (block 690 ), that gets through the block 670 certain correction addendum CA, otherwise the correction addendum CA, simply set to zero (Block 675 ).

In other words, as long as the required engine torque is negative and decreasing (curve G in FIG 8th , to the left of the minimum Q), the maximum increase gradient MRG (i) is set equal to the nominal increase gradient NRG (i). If, on the other hand, the required motor torque derivative increases (curve G in FIG 8th , to the right of the minimum Q), for example, because the demanded torque has almost reached a steady state after a decrease, or when the required engine torque has a positive value, for example, because the driver is depressing the accelerator pedal 426 to express a higher torque, the maximum increase gradient MRG (i) is calculated as the sum of the nominal increase gradient NRG (i) and the positive correction addendum CA (i), as in block 670 established.

In this regard, the block 670 calculate the correction addendum CA (i) using the following equation: CA (i) = K1 * K2 where K1 and K2 are two positive coefficients.

The coefficient K1 can be used with the ECU 450 can be determined on the basis of the motor speed value ES (i) and the value of the required torque (RT (i) two values as inputs of a calibration table 680 be used, which gives as output a corresponding coefficient K1. The calibration board 680 can be determined by experimental measures taken on a test engine of exactly the same type as the engine 110 and then in the storage system 460 be filed.

The coefficient K2 can be determined by the ECU 450 be determined on the basis of the required torque derivative RTD (i). In particular, this parameter can be used as the input of another calibration table 685 can be used, which gives as output a corresponding coefficient K2. The calibration board 685 can also be determined by experimental measures taken on a test engine of exactly the same type as the engine 110 and then in the storage system 460 be filed.

The effect of this solution is in 9 can be seen where, after the end of the release maneuver (curve A), the SOI controlled by the cylinder protection strategy increases faster at a higher rate and thereby shortens the overall duration of the cylinder protection strategy.

Although at least one exemplary embodiment has been presented in the foregoing summary and detailed description, it should be understood that a large number of variations exist. It should also be noted that the exemplary embodiment (s) are merely exemplary in nature and are not intended to limit the scope, applicability, or configuration in any way whatsoever. Rather, the foregoing summary and detailed description provide those skilled in the art with practical guidance for implementing at least one example embodiment, it being understood that various changes may be made to the function and arrangement of the elements described in an exemplary embodiment without to depart from the scope as set forth in the appended claims and their legal equivalents.

LIST OF REFERENCE NUMBERS

100

Automotive System

110

Internal combustion engine (ICE)

120

block

125

cylinder

130

cylinder head

135

camshaft

140

piston

145

crankshaft

150

combustion chamber

155

Cam Phaser System

160

fuel injector

170

Fuel pipe

180

high pressure pump

190

Fuel source

200

intake manifold

205

air line

210

inlet

215

valves

220

outlet

225

exhaust manifold

230

turbocharger

240

compressor

250

turbine

260

Intercooler

270

exhaust system

275

exhaust pipe

280

exhaust aftertreatment device

290

VGT actuator

300

Exhaust gas recirculation system (EGR)

310

EGR cooler

320

EGR valve

330

throttle

340

Mass flow and temperature sensor

350

Manifold temperature and pressure sensor

360

Combustion pressure sensor

380

sensors 380 for the coolant and the oil temperature and / or the associated fill level

400

Fuel rail pressure sensor

410

Camshaft position sensor

420

Crankshaft position sensor

430

Exhaust pressure and temperature sensor

440

EGR temperature sensor

445

Accelerator position sensor

450

Electronic control unit (ECM)

460

storage system

600

SOI calibration board

605

block

610

block

615

gradient limiter

620

Gradient calibration board

625

block

630

block

635

block

640

block

645

block

650

Gradient calibration board

655

block

660

block

665

block

670

block

675

block

680

calibration board

685

calibration board

Claims (9)

Electronic control unit ( 450 ) for an internal combustion engine ( 110 ) configured to cyclically: - control a value (ES (i)) of a motor speed, - control a value (RT (i)) of a motor requested torque, - a target value (SOI_T (i)) of a To determine the start of injection on the basis of the engine speed value (ES (i)) and the demanded torque value (RT (i)), - use the start of injection target value (SOI_T (i)), an injection start operation value (SOI_O (i )), - the engine ( 110 ) to perform a main injection and to use the injection start operating value (SOI_O (i)), the electronic control unit ( 450 ) is configured to determine the start of injection operating value (SOI_O (i)) by: - checking whether a cylinder protection strategy is activated or deactivated, - equating the start of injection operating value (SOI_O (i)) with the start of injection target value ( SOI_T (i)), when the cylinder protection strategy is deactivated - set the injection start operating value setting (SOI_O (i)) as a smaller injection start target value (SOI_T (i)) and an injection start maximum value (SOI_Max (i)); calculated by adding a specified injection start increment (ΔSOI (i)) to the injection start operating value (SOI_O (i-1)) detected at the previous cycle when the cylinder protection strategy is activated. Electronic control unit ( 450 ) according to claim 1, configured to activate the cylinder protection strategy when the value of the requested torque (RT (i)) is greater than a predetermined critical value thereof (RT_C) and less than the value of the required torque (RT (i - 1)). Electronic control unit ( 450 ) according to claim 1 or 2, configured to disable the engine protection strategy when the injection start operation value (SOI_O (i)) is equal to the injection start target value (SOI_T (i)). Electronic control unit ( 450 ) according to one of the preceding claims, configured to determine the start of injection increment (ΔSOI (i)) by: - determining a maximum rise gradient (MRG (i)) for the start of injection, - multiplying the maximum injection start increase gradient (MRG (i)) with a time interval (Δt) elapsed from the previous control cycle. Electronic control unit ( 450 ) is configured to determine the maximum injection start slope gradient (MRG (i)) based on the engine speed value (ES (i)) and the requested torque value (RT (i)). Electronic control unit ( 450 ) according to claim 5, configured to determine the maximum injection start increase gradient (MRG (i)) by: using the engine speed value (ES (i)) and the value of the requested torque (RT (i)) to determine a nominal increase gradient (NRG (i)), - calculating a value (RTD (i)) of a derivative of the demanded engine torque, - calculating the maximum increase gradient (MRG (i)) by adding a correction addendum (CA (i)) to the nominal increase gradient ( NRG (i)) if the value of the requested torque derivative (RTD (i)) is positive or greater than the value of the derivative of the requested engine torque (RTD (i-1)) in the previous cycle, - equating the maximum increase gradient ( MRG (i)) with the nominal increase gradient (NRG (i)) when the requested torque derivative value (RTD (i)) is negative and less than the requested engine torque derivative value (RTD (i-1)) in the previous cycle. Electronic control unit ( 450 ) according to claim 6, configured to derive the nominal increase gradient (NRG (i)) by using the engine speed value (ES (i)) and the value of the requested torque (RT (i)) as inputs of a first calculation ( 650 ), which gives as output a corresponding nominal increase gradient (NRG (i)). Electronic control unit ( 450 ) according to claim 6 or 7, configured to apply the nominal increase gradient correction addendum (CE (i)) (NRG (i)) based on the value of the requested torque derivative (RTD (i)), the engine speed value ( ES (i)) and the value of the required torque (RT (i)). Electronic control unit ( 450 ) according to claim 8, configured to determine the correction addendum by: using the engine speed value and the requested torque value as inputs of a second calculation giving as output a corresponding first correction coefficient, using the value of the requested engine torque derivative as the input of a third Calculation which gives as output a second correction coefficient, - calculation of the correction addendums as a function of the first and the second correction coefficients.

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