WO2011001057A2

WO2011001057A2 - System for calibrating the operating range of a supercharged internal combustion engine

Info

Publication number: WO2011001057A2
Application number: PCT/FR2010/051145
Authority: WO
Inventors: Eric Albin; Guillaume Martin; Thomas Peuchant; Vincent Talon
Original assignee: Renault S.A.S.
Priority date: 2009-07-01
Filing date: 2010-06-09
Publication date: 2011-01-06
Also published as: FR2947589A1; WO2011001057A3

Abstract

The invention relates to a calibration system for internal combustion engines supercharged by a turbocharger, including: a human-machine interface (69) for defining a list of values including at least two temperatures, two pressures, one speed of rotation and one dimensionless value, for accessing temperature and pressure maps (36) according to a table of operating points of an engine, and suitable for entering one or more values which make it possible to define an atmospheric temperature, an atmospheric pressure or a back pressure at the exhaust of an engine; an export module (71) suitable for transmitting or displaying a map of an amount of fuel injected according to an engine speed, and a pressure map or a map of valve or blade positions, in accordance with an engine speed.

Description

Calibration system for the operating range of a supercharged internal combustion engine

The invention relates to the field of regulation of internal combustion engines, and more particularly that of turbocharged supercharged engines.

The operating parameters of such engines, in particular the quantity of fuel injected at each engine cycle, and the supercharging pressure, ie the air pressure at the intake manifold at the inlet of the engine, engine cylinder, are established by maps, for example depending on the operating point (torque, speed) of the engine, under standard operating conditions of this engine. These maps are established for an altitude, an outside temperature, and a given loading level of the engine depollution means, for example a certain level of loading of a particulate filter. When the conditions of altitude, therefore of pressure, and of outside temperature vary, or when the backpressure increases between the upstream and the downstream of the depollution device, the use of a standard cartography of the operation of the engine can have a harmful or even destructive influence on a supercharged engine. For example, when climbing at altitude or going to an area warmer than that predicted by the mapping, the density of the air decreases, which has the immediate effect of reducing the air mass. entering the cylinders at each cycle. If we continue to inject the same amount of fuel as that recommended by standard mapping, during the heavy acceleration of the vehicle, the richness of the fuel mixture, that is to say the fuel / air ratio will exceed a critical limit and the engine will emit unsustainable amounts of unburned hydrocarbons. In addition, at high load, that is to say at high engine torque, the turbocharger may pack and exceed a critical speed, which may lead to the lifting of material on the compressor wheel. In order to take into account possible degraded atmospheric conditions, or variations of backpressure at the engine exhaust, several engine reference maps are established for different altitude parameters: outside temperature and exhaust backpressure value. The realization of these maps requires many measurements on suitable altimetry benches, the number of measurements being further multiplied by the different engine versions proposed for each vehicle.

The object of the invention is to propose a calibration system making it possible to determine fuel quantity maps to be injected and supercharging pressure maps, mappings adapted to control a supercharged engine under different conditions of temperature and atmospheric pressure, or to different exhaust backpressure conditions by performing a limited number of physical measurements on the vehicle.

The invention relates to a calibration system for turbocharged turbocharged internal combustion engines, comprising a human-machine interface and an export module.

The human-machine interface makes it possible to define a list of values comprising at least two temperatures, two pressures, a speed of rotation, and an adimensional value. The interface also provides access to temperature and pressure maps according to a table of operating points of an engine, for example by means of an interactive field making it possible to select a computer path to a file containing data. measurement results data on test bench. The interface also allows to enter one or more values from which it is possible to define an atmospheric temperature, an atmospheric pressure, or a counterpressure to the exhaust of an engine.

The export module is capable of transmitting or displaying a map of a quantity of fuel injected as a function of engine speed, and a map of pressures or a map of positions of valve (s) or vane (s). ), according to a scheme engine. The export module can display these maps on a screen, and transmit them simultaneously to a recording medium different from the screen memory.

According to a preferred embodiment, the man-machine interface makes it possible to define a temperature condition and a condition of atmospheric pressure or altitude.

According to an advantageous embodiment which can be combined with the previous one, the man-machine interface makes it possible to define an exhaust backpressure value or a loading value of a means of depollution to the exhaust.

The calibration system may notably include:

a mathematical model with adjustable parameters, capable of calculating a field of quantities listing temperatures and pressures at different points of an air circuit of a supercharged virtual engine, and listing the supply air flow rate of the virtual engine and the rotational speed of a virtual turbocharger of this engine, as a function of atmospheric temperature and pressure, the speed of the virtual engine, a fuel injection pattern, valve positions or control flaps the virtual engine air circuit, the geometrical configuration of a virtual turbocharger, and as a function of an exhaust counterpressure of the virtual engine,

identification means configured to assign values to the parameters of the model, as a function of a map connecting an array of operating points of the engine, and engine operating values, in particular the temperatures and pressures of a circuit of air of a real engine, an air supply flow rate of this circuit, and a rotational speed of a turbocharger of the engine,

a human-machine interface for assigning operating thresholds to certain critical magnitudes of the virtual motor's magnitude field, and for defining an atmospheric pressure test value and an atmospheric temperature test value, and / or a test value; counterpressure at the exhaust, a derating module configured to determine, for the temperature, pressure and / or pressure test values, and for a given speed of the virtual engine, a maximum quantity of fuel injected and a maximum boost pressure that can be impose on the virtual engine, without the critical quantities exceeding their respective operating thresholds,

an export module configured to transmit or display a map of the maximum quantity of fuel injected as a function of the speed of the virtual engine, and a map of the maximum boost pressure or the corresponding geometrical configuration of the virtual turbocharger, as a function of virtual engine schemes.

The mathematical model may also be able to calculate a pollutant species emission value of the virtual engine. In this case, the identification means can also take into account the difference between the emission values calculated by the model, and emission values measured on the actual engine. In this variant embodiment, the human-machine interface makes it possible to access, for example through an interactive tab making it possible to define a computer path to a file, to maps of pollutant thresholds as a function of fuel quantities injected into a motor. The maps thus selected by means of the interactive tab can be maximum emission maps that one wishes to tolerate for the engine.

The export module may also be configured to transmit or display a map according to the speed of the virtual engine, the maximum torque that the virtual engine can develop, or the maximum effective average pressure that can be obtained in an engine cylinder. virtual.

The export module may also be configured to transmit or display maps according to the speed of the virtual engine, the differences of the critical quantities to their respective thresholds, these differences being calculated for the maximum quantities of fuel injected and the supercharging pressures. maximum. According to a preferred embodiment, the derating module comprises an injection optimizer, able to determine a maximum quantity of fuel to be injected into the virtual engine. The injection optimizer is configured to perform a series of iterations for each engine speed of the operating point array, incrementing or decrementing at each iteration the amount of fuel injected, until the emission value of the virtual engine or the temperature of the gases leaving the cylinders of this engine, are greater than a minimum fraction of their respective thresholds, and that the emission value and the temperature of the gases at the cylinder outlet are both below their thresholds respectively.

According to another preferred embodiment, the derating module comprises a supercharging optimizer, able to determine a maximum acceptable gas pressure input of the cylinders of the virtual engine. The boost optimizer is configured to perform a series of iterations for each engine speed of the operating point table, incrementing or decrementing at each iteration the inlet gas pressure of the virtual engine cylinders, until at least one of the critical quantities other than the inlet gas temperature of the cylinders or the emission value, is greater than a minimum fraction of its operating threshold, and all the critical quantities are below their respective thresholds.

Preferably, the injection optimizer and the boost optimizer are configured to each perform an iteration, respectively on the amount of fuel injected and on the pressure of the inlet gases of the cylinders, and then to each perform a test on the a range of quantities calculated by the model with the new values of the amount of fuel injected and the pressure of the gases at the inlet of the cylinders, in order to decide whether the quantity of fuel and the pressure of the gases at the inlet of the cylinders must be incremented or decremented by 'next step. In an alternative embodiment, the man-machine interface may make it possible to define an iteration step of the quantity of fuel injected, and / or may make it possible to define an iteration step of the supercharging pressure.

The identification means may be configured to use, for example, the least squares method for determining the parameters of the model by comparing the map of operating values of the engine, and the fields of quantities calculated by the model for the same operating points as those of cartography.

The identification means may be configured to determine the parameters of the model so as to satisfy the following validity criterion: for at least one reference atmospheric pressure value, a reference atmospheric temperature value and a reference backpressure value, a series of magnitude fields is calculated by the model, each field of magnitudes making it possible to obtain a point of operation of the virtual engine from a list of operating points.

If a minimum proportion of these fields is included in a margin of proximity with respect to size fields acquired from measurements on a real supercharged engine for the same operating points, ie the same regimes and couples of the actual engine, then the model is deemed valid.

Other objects, features and advantages of the invention will become apparent on reading the following description, given by way of non-limiting example and with reference to the appended drawings, in which:

Figure 1 is a schematic view of a supercharged engine which is applied the calibration system according to the invention;

FIG. 2 represents a mathematical model of virtual engine used by the calibration system according to the invention; FIG. 3 illustrates a calibration process of an engine according to the invention;

FIG. 4 is an operating algorithm of an optimization module belonging to the calibration system according to the invention;

FIG. 5 is an operating algorithm of another optimization module belonging to the calibration system according to the invention; and FIG. 6 is an example of a human-machine interface making it possible to use a calibration system according to the invention.

FIG. 1 shows an internal combustion engine 1 with four cylinders, each cylinder being associated with a fuel injection device, referenced 2. One of the cylinders is equipped with an internal pressure sensor 21. The crankshaft (Not shown) is equipped with an angular position sensor 26, in particular to evaluate the speed, or speed of rotation of the engine. The injection devices 2 and the angular position sensor 26 are electronically connected to a first electronic control unit (ECU 1), referenced 9. The electronic control unit

9 conventionally includes a microprocessor or CPU, RAMs, ROMs, analog / digital converters and different input and output interfaces.

Fresh air, taken from the outside, first passes through an air filter 3, then a flow meter 4, before entering the compressor 5a of a turbocharger 5. Compressed air from the compressor 5a passes through a heat exchanger 10 which allows to cool the admitted gases. At the outlet of the exchanger 10, the cooled compressed air is sent through an intake valve 6 into an intake distributor 1 1 connected to the engine cylinders. The flue gases from the cylinders are discharged through an exhaust manifold 12, which sends these gases in particular to a turbine 5b of the turbocharger 5. Upstream of the turbine 5b, the exhaust manifold 12 also communicates with a recycling circuit 13. The recycling circuit 13 returns a portion of the flue gas in the inlet manifold 1 1. It comprises a valve 22 for regulating the flow of recycled gas. Upstream of the regulation valve 22 of the recycling circuit 13 is a heat exchanger 24 for cooling the recycled gases. The compressor

5a and the turbine 5b of the turbocharger 5 are mounted on a common shaft, the turbine driving the compressor in rotation. The turbine 5b is provided with fins (not shown) with a variable position, the position of which is regulated by the ECU 1 through a connection 23, and which makes it possible to adjust the power recovered by the turbine from the kinetic energy of the exhaust gases.

The power provided by the exhaust gas to the turbine could also be modulated by installing bypass valves allowing the gas flow to bypass the turbine partially (wastegate valves) or completely (bypass valves). It is also possible to provide the compressor with adjustable fins. We will designate by geometrical configuration of the turbocharger in order to regulate the flows of gas passing through this turbocharger, the positions of the bypass valves associated with the turbine, or the positions of the adjustable vanes of the turbine and / or the compressor.

The gases from the turbine 5b are returned to the outside atmosphere via an exhaust pipe 18 through a pollution control device 19 comprising, for example, an oxidation catalyst and / or a particulate filter, and then a outlet pipe 20. The set of pipes bringing the air or the recycled gases to the cylinders, or bringing the burnt gases to the outside, constitute the air circuit of the engine.

The electronic control unit 9 receives various signals allowing the operation of the system. In particular, it receives a signal indicating the engine speed, emitted by the sensor 26, and an instantaneous pressure signal in the cylinder equipped with the pressure sensor 21. The electronic control unit 9 emits various signals allowing the management of the operation of the engine. 1. It controls in particular through connections 25 the quantity of fuel injected into the cylinders of the engine at each cycle, and control by the connection 23 the boost pressure, or gas pressure in the inlet manifold 1 1, by varying the position of the blades of the turbine 5b. The amount of fuel injected at each engine cycle, and the timing of this injection, define an injection pattern. The electronic control unit 9 has maps 27 and 28 enabling it to read the quantity of fuel to be injected and the supercharging pressure to be imposed, to obtain an operating point of the engine, defined by a speed N, measured by the sensor. 26, and a torque C, determined from the measurements of the sensor 21. It also has a table 29 of values of operating points of the engine, corresponding to a list of couples of values (N, C) admissible for the engine. The engine 1 is also connected to an electronic control unit 30 (UCE2) which may be confused with, or may be distinct from, the electronic control unit 9. The UCE2 is connected to a group of pressure sensors 31 and a group of temperature sensors 32, arranged at different locations in the air circuit of the engine 1. The UCE2 is connected to the flowmeter 4 which transmits to it the values of the fresh air flow supplying the engine 1. The UCE2 is connected by a connection to a rotational speed sensor (not shown) transmitting thereto the speed of rotation of the turbocharger 5. The UCE2 is also connected to a transmission evaluator device 33, which allows it to record, possibly by reading manual of an operator, a value representative of the emissions (unburned hydrocarbons, soot ...) contained in the gases leaving line 20. This evaluation of the residual quantity of pollutants can be done e for example by taking a given quantity of gas and passing through a paper filter, then measuring the reflectance of the filter thus loaded, according to ISO measurement standard DP 10054 developed by Bosch. This gives a non-dimensional smoke index commonly referred to as FSN (Filter Smoke Number), from which it is known to calculate, by an empirical formula, the mass fraction of particles contained in the gas, in mg / m ³ . The UCE2 receives from the ECU 1, via a connection 34, the current values of the amount of fuel injected, the boost pressure in the manifold 11, and the operating point (speed, torque) of the engine 1.

The ECU 1 can be programmed to vary the quantity of fuel injected and the boost pressure of the engine 1, so that the operating point of this engine 1 passes successively by all the values listed in the table of points. operation 29. The UCE2 is capable of recording, for each of these operating points, a list of the values delivered by the various pressure sensors 31, the temperature sensors 32, the flowmeter 4, the rotational speed sensor of the turbocharger 5, the emission evaluation device 33, as well as the quantity of fuel injected and the supercharging pressure which made it possible to obtain the operating point considered for the engine 1. The UCE2 stores in a database 36, a field of values "data" grouping all the previous values, that is to say all the operating points listed in Table 29, and for each of these points the control values, in particular the quantity of fuel injected and the supercharging pressure, imposed by the ECU 1 to the engine 1, as well as the values measured by TUCE2 on the engine subjected to these control values.

FIG. 2 illustrates a virtual motor model 40 making it possible to represent the operation of the combustion engine 1 of FIG. 1. The virtual motor 40 comprises volumes 41, 42, 43, 44, 45, 46 and 47 representing portions of the pipe. of the air circuit of the engine 1, between the fresh air inlet of this engine and the exhaust of the engine 1. The virtual engine 40 also comprises volumes 48 and 49 representing portions of the recirculation circuit 13 of the engine. Exhaust of the engine 1. Between the different volumes 41 to 49 are interposed restrictions 51, 52, 53, 54 respectively representing the air inlet filter of the air circuit of the engine 1, the heat exchangers 10 and 24 of the engine 1, and its depollution device 19. The model 40 also includes restrictions 55 and 56 respectively representing the intake valve 6 and the valve 22 for regulating the flow of recycled gas from the engine 1.

The virtual engine 40 finally comprises a cylinder group model 60 and a turbocharger model 61 which comprises a compressor model 62 and a turbine model 63. The input and output values of the volume, restriction, group of cylinders, the turbine and the compressor are interconnected so that the virtual engine 40 is representative of the architecture of the real engine 1.

For example, the volume 41 representing a pipe portion upstream of the compressor 5a of the engine 1 is represented by a pressure value PAVC, a temperature value TAVC, a gas flow value Qm a. The volume 42 which represents a portion of pipe between the compressor 5a and the exchanger 10 of the engine

1, is represented by a pressure PAPC and a temperature TAPC and the same gas flow Qm a, since the only volume to flow into the volume 42, through the compressor model 62 is the volume 41. The volumes 44, 45 and 46, represented by their respective pressures PCOL, PAVT and PAPT and their respective temperatures TCOL, TAVT and TAPT model the intake manifold 1 1, the exhaust manifold 12 of the engine 1, and its portion of exhaust pipe 18 located upstream of the means of depollution 19.

The compressor model 62 is defined by relationships connecting a pressure and an upstream temperature, a downstream pressure and temperature, a through flow, and a compressor rotation speed C _T. The flow rate through the virtual compressor 62 is also equal to the value Qm a, the upstream temperature and pressure are respectively equal to the TAVC and PAVC values, and the downstream temperature and pressure are respectively equal to the TAPC and PAPC values.

Similarly, the virtual turbine 63 is characterized by equations connecting the rotational speed ω _τ which is identical to that of the virtual compressor 62, the flow rate of gas Qm passing through the virtual turbine 63, this flow also being the flow rate passing through the volume 46, by an upstream temperature TAVT and an upstream pressure PAVT which are also the temperature and the pressure prevailing in the volume 45, by a downstream temperature TAPT and a downstream pressure TAPT which are the temperature and the pressure prevailing in the volume 46. In general, each of the volumes 41 to 49 may be represented by a temperature, a pressure, a mass of gas that it contains, as well as by inflowing and outgoing gas flows. By writing the equations that reflect the evolutions of the mass and the heat energy of the gases contained in each of the volumes, as well as the relation of the perfect gases connecting pressure, volume, mass and temperature of the contained gases, and the first law of Joule connecting the heat energy, the mass and the temperature of these gases, we obtain a group of equations which is the contribution of the volume considered to the global model constituting the virtual engine 40.

The restrictions 5 1 to 55 are modeled by the Barre de Saint Venant equation connecting a generating pressure Pi, a pressure after restriction P, an upstream temperature Ti and an equivalent section A of the restriction, as well as the polytropic coefficient γ characteristic of the gas. These relationships are different depending on whether the flow regime is subsonic or supersonic, and are summarized in the following table:

Where r is the constant of the perfect gases.

Of course the debiting sections A are variable for the restrictions 55 and 56 representing valves.

The cylinder model 60 makes it possible to connect a flow of upstream gas Qm adm through the volume 44, an outgoing gas flow Qm e which is the flow of gas passing through the volume 45, a flow Qinj corresponding to a quantity of fuel injected and vaporized. in the cylinders, a rotational speed N of the virtual motor 1. The cylinder model 60 is likened to a positive displacement pump which absorbs gas from the volume 44 representing an intake manifold to return it to the volume 45 representing an exhaust manifold, by raising the temperature of the gas due to the combustion. , and spraying the injected fuel.

The gas flow entering the positive displacement pump is for example modeled by a polynomial which is a function of engine speed N and of the density p _adm

gas in volume 44, according to the formula: Qm adm = (X ₁ + X ₂ - N + X ₃ - N ² ) + (x ₄ + X ₅ - N + X ₆ -

p _adm

Where Qm_adm, N and p _adm are respectively the mass flow rate of gas entering the cylinders, the engine speed and the density of the gas in the volume 44 representing the intake manifold. The density p _{adm to} gas is itself a function of the temperature and the gas pressure in the volume 44. X ₁ , X ₂ , X ₃ , X ₄ , X ₅ , X 0 are coefficients of the polynomial, which can be adjustable parameters of the virtual motor model 40.

By writing the conservation of mass, we obtain the relation between the mass flow rate of gas Qm adm entering the cylinders, and the mass flow rate of gas Qm e coming out of the cylinders, and which includes the mass flow Qinj of vaporized fuel:

Qm _e = Qm _ adm + Qinj

The temperature TAVT of the gases leaving the cylinders is for example connected to the temperature Tcol of the gases entering the cylinders by an empirical relation of the following form:

Qinj PCI

TAVT = Tcol + λ ~

C _p - (Qm adm + Qinj)

Where Cp, PCI and λ are respectively the constant pressure heat capacity of the gas, a mass fuel calorific value and a combustion efficiency. This combustion efficiency λ, determined experimentally, depends in particular on the phasing of the injection or the pressure of the fuel supply rail.

The turbocharger model 61 makes it possible to connect the common rotational speed ω _τ of the turbine 63 and of the compressor 62, the mass flow rate Qm of gas passing through the compressor, which is the same, in steady state, as the mass flow rate of gas passing through. the turbine, and the PAVC, PAPC, PAVT and PAPT gas pressures respectively representing the gas pressures upstream and downstream of the compressor, and upstream and downstream of the turbine, by means of mappings of functions f, g, h and k defined as follows:

PAVT PAVT

Qm = h, ω ₇ n _t = k, ω _τ

PAPT PAPT

Thanks to these maps, the virtual motor model 1 can calculate the power Wt taken by the turbine on the kinetic energy of the exhaust gases and the power Wc consumed by the compressor to compress the gases passing through it, according to the formulas:

Where TAVC and TAVT represent the gas temperatures upstream of the compressor 62 and the turbine 63. The rotational speed ω _τ of the turbocharger is then calculated by integrating the difference between the two powers.

The virtual motor model 40 also takes into account the nonlinear behavior of the boost pressure regulation Pcol, representing the pressure in the volume 44. For a desired Boost pressure ConsPcol value, the model 40 searches the positions of the engine. fins that can make it possible to approach the desired supercharging pressure, and delivers, depending on the other input parameters of the model, a pressure

Supercharge pcol that we can actually get. This calculated pressure Pcol can in particular be lower than the setpoint pressure ConsPcol input into the model, if the turbine is already in a geometric configuration of maximum energy recovery and the pressure setpoint goes beyond the boost pressure reached . Figure 3 illustrates the operation of a calibration system according to the invention. FIG. 3 shows elements that are common to FIGS. 1 and 2, the same elements then bearing the same references. We find in particular the heat engine 1 and the database 36 that it has generated by recording lists of measured parameters for each of the operating points of the engine recorded in Table 29 of Figure 1. There is also the model virtual motor 40, which is a parametric model, that is to say that the equations that constitute it comprise variable parameters αl, α2, ... α, which can be modified to change the behavior of this virtual engine , so that the values delivered by this virtual motor model 40 are in adequacy with a field of experimental values, for example values recorded in the database 36. The calibration system according to the invention comprises a human interface referenced 69 which has an input interface 70 and an export module 71. The input interface 70 makes it possible to select data files, for example. file 36, which are then put in communication with an identification module 65.

The identification module 65 is connected to the virtual engine 40, whose input data can be varied (for example the atmospheric conditions, the quantity of fuel injected, the boost pressure control, etc.) and the parameters of the engine. adjustment α1, α2,..., α, (for example coefficients of a polynomial characterizing the flow of air entering the cylinders of the engine). The identification module 65 varies the parameters α1, α2, ... α _j , of the virtual engine model 40 until a certain number of values calculated by this model, such as the temperatures and pressures at the different volumes 41 to 47, the speed of rotation of the turbocharger 61, the air flow to the engine or a richness of the gases burned fractional hydrocarbons, are all sufficiently close to the corresponding values measured on the engine 1 and recorded in the database data 36. To do this, the identification module 65 performs a series of calculations parameterized by the values α1, α2,..., So that the virtual motor 40 passes successively through all the operating points N, C recorded. in Table 29 of Figure 1, these operating points are also recorded in the database 36. The identification module 65 imposes for this the same conditions of temperature and pressure as well as the same exhaust against that those which have made it possible to determine the database 36 using the engine 1. By using, for example, the least squares method, the identification module 65 determines the values of the parameters α 1, α 2,..., Α, for which we obtain, on the virtual motor 40, values of temperatures, pressures, air flow supplying the engine, turbocharger rotation speed and emission of pollutant species sufficiently close to the values recorded in the database 36.

In order to validate the parameters α1, α2,..., Αj of the model, the identification module 65 may for example apply the following criterion.

For each of the temperature, pressure, turbocharger speed, air flow or pollutant emission values, the difference between the corresponding value calculated by the virtual motor model 40 and the corresponding value is examined. measured on the actual engine 1. For each of these quantities, a difference threshold is defined, which may be different depending on the quantity considered, but which is the same whatever the operating point of the motor. Then we look at the percentage of operating points listed in Table 29 for which the differences between actual value and calculated value are in each case within the predefined deviation threshold for the type of magnitude in question. For example, it may be considered that the virtual motor model 40 is satisfactory, if for more than 90% of the operating points listed in Table 29, all the differences between real values and calculated values are less than the expected difference threshold. The validity criterion of the model can then be summarized by the following table:

(*) Dimensional value FSN "Filter smoke Number" varying between 1 and 10, measured according to the ISO DP 10054 standard.

The input interface 70 also makes it possible to send to a calibration module 66 critical value thresholds representing, for example, temperatures and pressures upstream and downstream of a compressor, and a pressure ratio between the upstream and the downstream of a compressor. The input interface 70 also makes it possible to put the calibration module 66 in relation with a map 72 in which, for example, the FSN index threshold values for the gas flows are recorded, depending on a quantity of fuel. injected into an engine. The input interface 70 also makes it possible to put the calibration module 66 in relation with the database 36. The input interface 70 also makes it possible to send values to the calibration module 66 for defining environmental conditions or exhaust backpressure conditions, that is to say for example an external temperature value. an external pressure value or an altitude value, an exhaust backpressure value or a relative value quantifying the loading level of a pollution control means such as a particulate filter.

The calibration module (also known as a decoupling module) 66 comprises an injection optimizer module 67 and a booster optimizer module 68. The calibration module 66 is able to launch simulation calculations by means of the virtual engine 40.

For a given engine speed N, corresponding, for example, to one of the operating points (N, C) (ie (speed, torque)), recorded in the operating point table 29 of FIG. 1, and retranscribed in FIG. In the database 36, the calibration module 66 performs a first calculation using the virtual motor model 40, by imposing on this virtual engine the maximum injected fuel quantity InJ ₀ (N) recommended by the map 27 and the maximum boost pressure Pcol _o (N) recommended by the map 28 for this engine speed. These values are for example retrieved from the database 36, where they have been retranscribed. The values of temperature and atmospheric pressure, as well as the exhaust backpressure value used for this calculation, are those defined by the interface 70.

The injection optimizer module 67 and the booster optimizer module 68 then each perform in turn an incrementation or decrement Δinj the amount of fuel injected, and an incrementation or decrement ΔPcol of the supercharging pressure. The calibration module 66 then restarts a calculation at the level of the virtual engine 40 and compares some of the values calculated by the model 40 with the thresholds of critical values defined by means of the input interface 70, or in the mapping of thresholds. issue 72. According to the result of the comparison, the calibration module 66 performs a new iteration by incrementing and / or decreasing the quantity of fuel injected and the boost pressure, or sends the export module 71 the current values of the quantities of fuel and boost pressure, which are then recorded as the maximum values of injected fuel quantity and boost pressure for the engine speed N considered.

After the calibration module 66 has performed this procedure for each N engine speed value of the operating point array 29, the export module 71 thus has two tables of values. A table of values records the maximum quantity of injected fuel allowed according to the speed of the engine, and a table of values records the maximum boost pressure allowed according to the engine speed. These tables of values are valid for the temperature and atmospheric pressure, and for the exhaust backpressure that have been defined through the input interface 70.

The export module can either display these values on a screen, or send them as calculation files to a database or an external computing unit.

FIG. 4 illustrates the operation of an injection optimizer module 67 of FIG. 3. There are elements that are common to FIG. 3, the same elements then bearing the same references. Following a calculation initiated by the calibration module 66, the injection optimizer 67 receives from the virtual engine 40 an "Emiss" value quantifying the polluting species emitted by the engine 40, and a value TAVT representing the temperature of the gases in the engine. volume 45 of the virtual engine. These two values are sent respectively to the multiplicative branches of two dividers 80 and 81. The optimizer

67 also receives from the interface 70 a threshold value TAVT that the user entered manually in the interface, and that the optimizer 67 sends on a dividing branch of the divider 81. The optimizer 67 reads in the map 72 that it has been designated means of the interface 70 by the user, depending on the amount of injected fuel "Inj" which was used to perform the last simulation calculation of the virtual engine 40, a threshold value Emiss (Inj) which is the maximum value d emission that one wishes to accept for the engine.

The current value of fuel quantity injected Inj is the sum of the value InJ ₀ (N) that the calibration module 66 reads in the database 36, and an increment value Δlnj defined by the optimizer module of injection 67 at the previous computation step.

The optimizer module 67 sends the value ThresholdEmiss (Inj) to a dividing branch of the divider 80. The values calculated by the divisors 80 and 81 are respectively sent to comparator modules 82 and 84 which perform a test to know whether the computed values are strictly greater than 1, that is, if the calculated emission and temperature values before turbine are greater than the desired threshold. The values calculated by divisors 80 and 81 are also sent respectively to comparators 83 and 85 which test whether the calculated ratios are less than or equal to a lower threshold value which is here chosen equal to 0.95.

The results of the comparators 82 and 84 are sent on a logic operator 86 "OR" which delivers a value "1" if one or the other of the two values is strictly greater than 1, and which delivers a value "0" in the opposite case. The operator 86 sends the result on a logic switch 87 which multiplies this result by -1 and sends it on a branch of an adder 89. The results of the comparators 83 and 85 are sent on a logical operator 88 "AND" which delivers a value equal to "1" if the two results are simultaneously less than or equal to 0.95 and which delivers a value "0" otherwise. The result of the operator 88 is sent to another branch of the summator 89. According to the results of the logic tests 86 and 88, the adder 89 delivers an incrementation direction value which can be equal to 0, 1 or -1, and that is sent on a branch of another summator 90, which receives on a second input, a delay function 91 causing it the incrementation direction value calculated during the previous simulation of the virtual engine 40. The result is an updated direction of variation which is sent on a multiplier 92 which multiplies it by a value K1. The value Kl, which represents the maximum amplitude of the iteration steps on the quantity of fuel injected, can be intrinsic to the calibration system, or can be defined by the user through the interface 70.

The result delivered by the multiplier 92 is a value Δlnj that the calibration module 66 adds by a summator 93 to the value InJ ₀ (N) read in the database 36, to obtain the value Inj of the amount of fuel injected used. to perform the following simulation calculation of the virtual engine 40.

The injection optimizer module 67 will therefore decrement the quantity of injected fuel Inj, as long as the two values Emiss and

TAVT, representing the emissions of the virtual engine 40 and the temperature at the exhaust manifold of the engine 40, are greater than the threshold which has been allocated to them by the user by means of the interface 70. The optimizer module 67 goes to the contrary increment the amount of fuel injected Inj if he finds that the two values

Emiss and TAVT are simultaneously below the thresholds and more than 5% apart from the thresholds that have been allocated to them respectively. The incrementation or decrementation iterations therefore stop once the two values are lower than their respective thresholds, and at least one of the two values is included in a margin between 95% and 100% of the threshold allocated to the magnitude in question.

FIG. 5 illustrates the operating principle of the supercharging optimizer module 68. Following a simulation run by the calibration module 66, the optimizer 68 receives from the virtual engine 40 an Nturbo value representing the rotation speed of the virtual turbocharger 61, a PAPC value representing a pressure in the volume 42 of the virtual engine 40, a TAPC value representing a temperature in the same volume 42, a PAVT value representing a pressure in the volume 45 of the virtual engine 40, a value Pcol representing a pressure in the volume 44 of the virtual engine 40, and an Compr value representing a compression ratio obtained by dividing a pressure in the volume 42 of the engine 40, by a pressure in the volume 41 of the engine 40. The volumes 41, 42, 44 and 45 of the virtual engine 40 respectively represent a compressor front zone, an after-compressor zone, an intake manifold and an exhaust manifold of an internal combustion engine of structure similar to that of the engine. 1.

The values Nturbo, PAPC, TAPC Compr, and PAVT are respectively sent on a multiplier branch of divisors 100, 101, 102, 103 and 104. The value Pcol is sent on a dividing branch of a divider 105. The optimizer 68 receives of the threshold value interface 70, namely SeuilNturbo, SeuilPAPC, ThresholdTAPC, ThresholdCompr and ThresholdPAVT, entered manually by the user, and which represent desired maximum values of downstream turbocharger, pressure and temperature rotation speed. compressor, compression ratio between upstream and downstream of a turbocharger, and pressure in an exhaust manifold of an internal combustion engine. SeuilNturbo values,

ThresholdPAPC, ThresholdTAPC, ThresholdCompr and ThresholdPAVT are respectively sent on a dividing branch of divisors 100, 101, 102, 103 and 104. Boost optimizer 68 receives on a multiplicative input of divider 105 a ConsPcol value representing a setpoint pressure at the level of of the volume 44 of the virtual engine 40.

This ConsPcol value is for example a vane position control signal of the virtual turbine 63, expressed as a function of the pressure that is desired to reach at the volume 44 representing the intake manifold of the virtual engine 40.

The results obtained by the divisors 100, 101, 102, 103, 104 and 105 are respectively sent to comparators 106, 107, 108, 109, 110 and 111 which perform a test to know if the values found are strictly greater. to 1. The results of all these tests are sent on a logic operator 124 "OR" which delivers a value "1" as soon as one of the preceding values is strictly greater than 1, and which delivers the value "0" in the opposite case. The result of the logic operator 124 is sent to a logic switch 1 18 which multiplies the result by -1 and sends it to an input of an adder 1 19.

The results of the divisors 100, 101, 102, 103 and 104 are also sent respectively to comparators 1 12, 1 13, 1 14, 1 15 and 1 16, which test whether the values found are less than or equal to a minimum threshold value which is here chosen equal to 0.95. The result of these tests is sent on a logical operator 125 "AND" .The result of the divider 105 is sent on a comparator 1 17 which carries out a test to know if the result found is less than or equal to 1, and also sends it on an input of the logical operator 125. The logical operator 125 delivers a Boolean value which is equal to "1" if all its inputs are true and delivers a Boolean value equal to "0" otherwise, especially if one of the values calculated by the divisors 100, 101, 102, 103, 104 is greater than 0.95.

The result of the logic operator 125 is sent to an input of the adder 1 19, which delivers an incrementation direction value on an input of a summator 120. The adder 120 itself receives, on one of its inputs, the result of a delay function 121, so as to output at its output a sum of the incrementation directions calculated from the first iteration performed for the current regime N of the virtual motor 40. The sum of the incrementation steps, delivered by the summator 120, is sent on a multiplier 122, which multiplies this value by an amplitude K2. The amplitude K2 which represents a step size of incrementation of the boost pressure of the virtual motor 40. The value K2 may be a value intrinsic to the calibration system or may be a value entered by the user by means of a interface 70.

The result of the multiplier 122 is a pressure increment ΔPcol that the calibration module 66 sends on a summator 123 where it is added to the value Pcolo (N) extracted from the database 36. The result delivered by the adder 123 is a ConsPcol value representing a boost pressure setpoint. If this setpoint is different from that calculated at the previous iteration, it is used by the calibration module 66 to start a new calculation of the virtual engine 40. In this case, the ConsPcol value is also returned to a multiplicative input of the divider 105. .

Thus, the boost optimizer module 68 will decrement the ΔPcol value if one of the critical values Nturbo, PAPC, TAPC, Compr or PAVT is greater than the threshold defined by the user. It will also decrement the value ΔPcol if the boost pressure setpoint ConsPcol entered in the model is not finally reached once a simulation has been carried out using the virtual engine 40, which may mean that the control fins of the virtual turbine 63 have reached a limit position. In this case, the module 68 decrements the pressure setpoint in order to return to the achievable setpoint range. On the contrary, the optimizer 68 will increment the boost pressure setpoint ConsPcol as long as at least one of the critical quantities Nturbo, PAPC, TAPC, Compr and PAVT has not reached a certain proximity threshold, by a lower value, the threshold that has been allocated by the user. The proximity threshold is here set at 95% of the threshold value not to be exceeded, but could be set to a different value, or could be set to different values for each of the quantities considered.

FIG. 6 illustrates a human-machine interface 69 of a calibration system according to the invention. The human-machine interface 69 comprises in its left part a data input interface 70 and in its right part, a graphic export module 71 making it possible to visualize, in the form of curves, engine control mappings calculated by the calibration system 66 of FIG. 3. The data entry interface 70 comprises a first interactive field 130 making it possible to select a computer path to a file containing results data. The interface also includes an interactive field 131 for selecting a path to a map, for example the map 72 of FIG. 3, which lists threshold values of pollutant emissions tolerated, depending for example on the amount of fuel injected into the engine. The interface 70 has digital input ranges 132 and 133 for defining an altitude of the vehicle and a temperature outside it. An interface could also be considered for entering outside air pressure and outside air temperature, or entering only one of these values. The interface 70 also comprises a field 134 allowing here the entry of a percentage rate of loading of a particulate filter. One could also consider an interface that would allow to directly enter a value of counterpressure to the exhaust. One would not depart from the scope of the invention if the interface could only enter one or two of the values mentioned above.

The interface may also include an interactive field 135 for selecting a file corresponding to the mathematical model of virtual engine 40 that is to be used.

The interface 70 also includes a series of digital fields

136 which are here six in number, and allow to define a group of quantities deemed critical for the operation of the engine.

These critical quantities include a SeuilNturbo turbocharger rotation speed threshold expressed in revolutions per minute, threshold pressure thresholds PAPC and SeuilPAVT at the output of a turbocharger and at the output of cylinders, expressed in millibars.

(1 millibar worth approximately 100 Pa), and TAPC and TAVT temperature thresholds at the exit of the turbocharger and at the outlet of cylinders, expressed in degrees Celsius.

There is also a dimensionless value SeuilCompr representing the pressure ratio between the inlet and the outlet of the turbocharger. The interface 70 finally includes an activation box

137 to validate the input of the data listed above and to start the calibration operation itself. The export interface 71 displays curves 141, 142, 143 which are a function of a motor speed N which is here typically between 1000 and 5000 revolutions / minute.

Curve 141 shows the maximum injected fuel quantity values Injmax calculated by the calibration module 66, for the temperature and atmospheric pressure conditions defined in cells 132 and 133 and for the exhaust backpressure defined at box 134. The fuel quantity injected values are here displayed in mg / shots, and are for example between 20mg / shot and 80mg / shot.

The curve 142 shows the maximum boost pressure values Pcolmax determined by the calibration module 66, again for the same conditions of temperature and external pressure and for the same exhaust backpressure. These values are for example between 1000 mbar and 3000 mbar.

Curve 143 shows the average effective pressure values PME in the cylinders of the engine 40, for the same operating conditions of the engine as those for obtaining the curves 141 and 142. This value, expressed in bar, can for example be between 5 and 30 bar, ie 500 000 and 3000 000 Pa. The effective mean pressure is obtained by integrating on a cycle of the engine, the pressure of gas in a cylinder on the variations of internal volume of the cylinder. This value is proportional to the torque developed by the motor.

The curves 141 and 142 can be a superposition of the initial operating limit curves of the motor 1 of FIG. 1, namely InJ ₀ (N) and Pcol _o (N), and new calculated curves, Injmax (N) and Pcolmax ( NOT). In the example of Figure 6, the initial curves are represented in solid line, and the new curves are represented by their calculation points. The same representation convention is repeated for the initial effective average pressure curve and the new average effective pressure curve 143. The export interface 71 also includes graphs 144, 145, 146, 147, 148, 149, 150 making it possible to display the percentages of difference to the threshold values defined using the fields 131 and 136 of the interface of FIG. input 70, corresponding magnitudes of the virtual motor 40 under the operating conditions of the curves 141 and

142. For example, each graph displays the report of one of the magnitudes to be monitored, by the threshold that has been allocated to it, limiting the display to values between 80% and 100%. These graphs 144 to 150 make it possible to see, for each speed of the engine, which operating variables of the engine have been decisive for imposing a limitation on the quantity of fuel injected or on the supercharging pressure.

The calibration system according to the invention limits the number of vehicle tests, which saves the price of the tests themselves, and saves time on the development of the vehicle, especially if the quantity maps fuel and boost pressure must be established when the number of available altimetry benches or the number of existing vehicles is reduced.

Claims

A calibration system for turbocharged turbocharged internal combustion engines, comprising:

a human-machine interface (69) for defining a list of values (136) comprising at least two temperatures, two pressures, a speed of rotation, and a dimensionless value, making it possible to access (130) maps (36); ) of temperatures and pressures according to an array (29) of operating points of an engine (1), and making it possible to enter one or more values (132, 133, 134) from which it is possible to define an atmospheric temperature, an atmospheric pressure, or a counterpressure at the exhaust of an engine,

an export module (71) capable of transmitting or displaying a map (141) of a quantity of fuel injected as a function of an engine speed, and a map of pressures (142) or a mapping of valve positions (s) or fin (s), depending on engine speed.

2. Calibration system according to claim 1, wherein the human-machine interface (69) makes it possible to define a temperature condition and a condition of atmospheric pressure or altitude.

Calibration system according to one of the preceding claims, in which the man-machine interface (69) makes it possible to define an exhaust backpressure value or a loading value of an exhaust pollution control means. .

Calibration system according to one of the preceding claims, comprising:

a mathematical model (40) with adjustable parameters, capable of calculating a field of quantities listing temperatures and pressures at different points of an air circuit of a supercharged virtual engine, and listing the supply air flow rate of the virtual engine and the speed of rotation of a virtual turbocharger (61) of this engine, as a function of the atmospheric temperature and pressure, of the engine speed. virtual engine, a fuel injection pattern, valve positions or control flaps (55, 56) of the virtual engine air circuit, the geometrical configuration of a virtual turbocharger (61), and function of an exhaust counterpressure of the virtual engine,

identification means (65) configured to assign values to the parameters of the model, as a function of a map (36) connecting an array (29) of operating points of the engine, and engine operating values, in particular temperatures and pressures of an air circuit of a real engine (1), an air supply rate of this circuit, and a rotational speed of a turbocharger of the engine,

a human-machine interface (69) making it possible to assign operating thresholds (136) to certain critical quantities of the magnitude field of the virtual motor, and making it possible to define an atmospheric pressure test value and an atmospheric temperature test value, and / or an exhaust backpressure test value,

a derating module (66) configured to determine, for the temperature, pressure and / or pressure test values, and for a given speed of the virtual engine, a maximum quantity of fuel injected and a maximum boost pressure that the it is possible to impose on the virtual engine, without the critical quantities exceeding their respective operating thresholds,

an export module (71) configured to transmit or display a map of the maximum quantity of fuel injected as a function of the speed of the virtual engine, and a map of the maximum boost pressure or a map of the corresponding geometrical configuration of the turbocharger virtual, based on virtual engine speeds.

Calibration system according to Claim 2, in which the mathematical model (40) is also able to calculate a pollutant emission value of the virtual engine, in which the identification means (65) take into account the difference between the emission values calculated by the model (40) and emission values measured on the real engine (1), and in which the human-machine interface (69) makes it possible to access (131) mappings ( 72) of emission thresholds according to the quantities of fuel injected into an engine.

6. Calibration system according to one of the preceding claims, wherein the export module (71) is also configured to transmit or display a map (143) according to the speed of the virtual engine, the maximum torque that can develop the virtual motor, or the maximum effective average pressure that can be obtained in a cylinder of the virtual engine.

Calibration system according to one of the preceding claims, in which the export module (71) is also configured to transmit or display mappings (144, 145, 146, 147, 148, 149, 150) as a function of the speed of the virtual engine, deviations of the critical quantities from their respective thresholds, these differences being calculated for the maximum fuel quantities injected and the maximum supercharging pressures.

8. Calibration system according to one of claims 5 to 7, wherein the decoupling module (66) comprises an injection optimizer (67), able to determine a maximum amount of fuel to be injected into the virtual engine, configured for performing a series of iterations for each engine speed of the operating point array (29), incrementing or decrementing at each iteration the amount of fuel injected, until the emission value of the virtual engine or the temperature of the gases leaving the cylinders of this engine, are greater than a minimum fraction of their respective thresholds, and the emission value and the temperature of the gases at the cylinder outlet are both lower than their respective thresholds.

9. Calibration system according to one of the preceding claims, wherein the decoupling module (66) comprises a boost optimizer (68), able to determine an acceptable maximum pressure of the inlet gas cylinders of the virtual engine, configured to perform a series of iterations for each engine speed of the operating point array (29), incrementing or decrementing at each iteration the inlet gas pressure of the virtual engine cylinders, until at least one critical quantities other than the cylinder inlet gas temperature or the emission value, being greater than a minimum fraction of its operating threshold, and that all the critical quantities are below their respective thresholds.

Calibration system according to Claim 8 and 9, in which the injection optimizer (67) and the boost optimizer (68) are each configured to perform an iteration, respectively on the quantity of fuel injected and on the pressure of the gases at the inlet of the cylinders, then to each perform a test on the field of quantities calculated by the model (40) with the new values of the quantity of fuel injected and the pressure of the gases at the inlet of the cylinders, in order to decide whether the amount of fuel and cylinder inlet gas pressure must be incremented or decremented in the next step.