FR3043142B1 - METHOD AND DEVICE FOR MANAGING PETROL INJECTION IN A CYLINDER OF A COMBUSTION ENGINE OF A MOTOR VEHICLE - Google Patents

Abstract

The present invention relates to a method for managing the direct injection of gasoline into a cylinder of an internal combustion engine of a motor vehicle. The method comprises the steps of determining the power required for the fuel injection from a predetermined number of injections and a predetermined value of the injector control current intensity, estimate (E2). the power available at the converter from the temperature of the electronic control unit and the voltage of the power supply battery, when the power required is less than the available power, injection (E5) d essence of the predetermined number of injections to the predetermined control current, and when the required power is greater than the available power, reducing (E11) the fuel pressure.

Description

The present invention relates to the automotive field and relates more particularly to a method and a device for managing the direct injection of gasoline into a cylinder of a combustion engine of a motor vehicle.

In a gasoline engine with direct injection of a motor vehicle, it is known to produce in each cylinder a plurality of gasoline injections during the same combustion cycle of the engine in order, in particular, to reduce the emissions of pollutants or prevent self-ignition of gasoline, that is, uncontrolled ignition of fuel.

The fuel injectors of the engine are current-controlled by a computer, called an electronic control unit, via a DC direct current converter, commonly called DC / DC converter ("Direct Current / Direct Current" in English). . This converter is controlled by a computer which determines in known manner the number of injections to be made. The DC / DC converter converts the voltage delivered by the vehicle's battery, a nominal value of 12 V but which in reality can vary between 9 and 14 V depending on the use that is made by the various equipment of the vehicle, in a higher injection voltage, for example of the order of 65 V. This injection voltage corresponds to a control current of the high injector, of the order of 12A to 16A, which is necessary to successfully inject the essence of the injection rail in the cylinder via the injectors, the internal pressure of the fluid in the injection rail being high in operation, for example of the order of 250 bars.

The requirements in terms of the number of injections vary in a known manner according to the type of engine and its operating points, that is to say its speed, the torque requested by the driver via the accelerator pedal, the temperature of the engine. the water and the temperature of the air admitted into the engine to make it work.

Also, in known manner, the electronics of the computer is sized to respond to the injection profile in the worst case, namely a maximum fuel pressure, which corresponds to a maximum injectors control current, a low battery voltage, for example less than 9 V, and an air temperature in the calculator at the usual limits, for example - 40 ° C and + 135 ° C.

The calculator is thus oversized for most "nominal" operating cases. The operation of the computer is not optimized, which is expensive, particularly in terms of dimensioning the components and therefore the size of the electronic control unit, and therefore has significant disadvantages. The invention aims to remedy at least in part these disadvantages by providing a simple, reliable and effective solution for managing the direct injection of fuel in a motor vehicle gasoline engine. To this end, the invention firstly relates to a method for managing the direct injection of gasoline into a cylinder of an internal combustion engine of a motor vehicle, said vehicle comprising an internal combustion engine at least one power supply battery, an electronic control unit and a dc direct current converter, said motor comprising a plurality of cylinders, each of said plurality of cylinders comprising an injector driven by the unit electronic control device via said converter for injecting gasoline into said cylinder, said method being remarkable in that it comprises: a step of determining the power required for fuel injection from a predetermined number of injections and a predetermined value of intensity of the injector control current; the power available at the converter from the temperature of the electronic control unit and the voltage of the battery, • a step of comparing the required power with the available power, • when the power required is less than the available power and when the temperature of the electronic control unit is less than a predetermined maximum temperature value, a fuel injection step of the predetermined number of injections, the predetermined control current and the current voltage of the power supply battery, and reset of a control counter, and • when the required power is greater than the available power and the fuel pressure is greater than a predetermined minimum pressure value, a step of decreasing the fuel pressure to reduce the power required.

Preferably, the method comprises, when the power required is greater than the available power but the fuel pressure is equal to the predetermined minimum pressure value, a fuel injection step of the predetermined number of injections, at the predetermined minimum pressure value and at a nominal voltage of the electric supply battery, and a step of incrementing the control counter.

The function of the control counter is to limit the operating time of the DC direct current converter when the required power is greater than its available power, and therefore it operates at its maximum power. The control counter is defined by a number of passages of the method according to the invention by the fuel injection step of the predetermined number of injections, at the predetermined minimum pressure value and at a nominal voltage of the battery. power supply. The maximum value of the control counter represents the maximum operating time when the computer temperature is above its maximum temperature.

According to one aspect of the invention, the method comprises, when the required power is less than the available power, when the temperature of the electronic control unit is greater than a predetermined maximum temperature value and when the control counter is equal. at a predetermined maximum increment value, a step of reducing the motor torque.

According to one aspect of the invention, the engine torque reduction step is performed in the absence of an alternator configured to adapt the voltage of the power supply battery in the vehicle.

Advantageously, when the power required is less than the available power, when the temperature of the electronic control unit is greater than a predetermined maximum temperature value and when the control counter is different from a predetermined maximum increment value, then the process comprises: • when the fuel pressure is above a predetermined minimum pressure value, a step of decreasing the fuel pressure to reduce the required power, • when the fuel pressure is equal to the minimum value of predetermined pressure, a fuel injection step of the predetermined number of injections at the predetermined minimum pressure value and a nominal voltage of the power supply battery and a step of incrementing the control counter.

In one embodiment, the vehicle comprising an alternator configured to be controlled by the electronic control unit and to adapt the voltage of the battery, the method furthermore comprises, on the one hand, when the power required is greater than the power available or when the control counter is different from a predetermined maximum increment value, and secondly when the voltage of the power supply battery is below a predetermined voltage rating, a step of increasing the voltage of the battery, preferably to reach the required power that is implemented by said alternator.

According to one characteristic of the invention, the predetermined number of injections is determined from the engine speed, its torque and its temperature. The invention also relates to an electronic control unit for managing the direct injection of gasoline into a cylinder of an internal combustion engine of a motor vehicle, said vehicle comprising an internal combustion engine, at least one battery power supply unit and a dc direct current converter, said motor comprising a plurality of cylinders, each of said plurality of cylinders comprising an injector driven by the electronic control unit via said converter for injecting the gasoline in said cylinder, said electronic control unit being remarkable in that it comprises: a determination sub-unit configured to determine the power required for fuel injection from a predetermined number of injections and a predetermined value of intensity of the injector control current, us-unit of estimation configured to estimate the available power at the converter from the temperature of the electronic control unit and the voltage of the power supply battery, • an injection sub-unit configured to injecting gas of the predetermined number of injections, the predetermined control current and the current voltage of the power supply battery, and to zero a control counter, • a decrease subunit configured to decrease the fuel pressure to reduce the power required.

Preferably, the predetermined number of injections is determined from the engine speed, torque and temperature.

Advantageously, the electronic control unit further comprises a reduction subunit configured to reduce the engine torque.

Advantageously, the electronic control unit further comprises a control sub-unit configured to control an increase in the voltage of the battery to reach the required power. The invention finally relates to a motor vehicle comprising an internal combustion engine, at least one power supply battery, an electronic control unit and a DC direct current converter, said motor comprising a plurality of cylinders, each cylinder of said plurality of cylinders comprising an injector current-controlled by the electronic control unit for injecting gasoline into said cylinder, said vehicle being characterized in that it comprises an electronic control unit as presented above. Other features and advantages of the invention will become apparent from the following description given with reference to the appended figures given by way of non-limiting examples and in which identical references are given to similar objects: FIG. 1 schematically illustrates the vehicle according to the invention. FIG. 2 schematically illustrates an example of determining the power required to inject gasoline into the engine cylinders of the vehicle of FIG. 1. FIG. 3 schematically illustrates an embodiment of the method according to the invention. The electronic control unit according to the invention is intended to be mounted in a motor vehicle to allow optimized management of the direct injection of gasoline into the cylinders of the combustion engine of said vehicle.

With reference to FIG. 1, the vehicle 1 comprises an internal combustion engine 10, an electric supply battery 20, an electronic control unit 30 and a DC direct current converter 40 called the DC / DC converter.

In one embodiment, it will be appreciated that the electronic control unit 30 may comprise the converter 40.

The engine 10 comprises a plurality of cylinders 12 and each cylinder 12 of said plurality of cylinders comprises an injector 120 controlled by current by the electronic control unit 30 in order to inject gasoline into said cylinder 12.

In a first embodiment, the vehicle 1 comprises a so-called "steerable" alternator 50 configured to vary the voltage of the battery 20.

In a second embodiment, the vehicle 1 is devoid of an alternator configured to vary the voltage of the battery 20. The electronic control unit 30 according to the invention comprises a subunit of determination 310, a subunit 320, an injection subunit 330, a subunit 340, a subunit 350 and a steering subunit 360. The electronic control unit 30 further comprises a counter CTR control that can be incremented step by step until reaching a predetermined maximum value CTRmax or that can be reset.

Determination subunit 310 is configured to determine the power required for gasoline injection from a predetermined number of injections and a predetermined amount of injector control current 120.

The estimation subunit 320 is configured to estimate the power available at the converter 40 from the temperature of the electronic control unit 30 and the voltage of the power supply battery 20.

The injection subunit 330 is configured to control the converter 40 from the current voltage of the power supply battery 20 to control the injectors 120 for injecting fuel a predetermined number of times. in each cylinder 12 during the same combustion cycle of the engine 10 when the power required to achieve this predetermined number of injections is less than the available power estimated by the estimation subunit 320.

Injection subunit 330 is also configured to zero the CTR control counter.

Decrease subunit 340 is configured to decrease the fuel pressure to reduce the power required.

The reduction subunit 350 is configured to reduce the torque of the motor 10.

The driving sub-unit 360 is configured to control an increase in the voltage of the battery 20 to the required power.

In the first embodiment of the vehicle 1 according to the invention in which the vehicle 1 comprises a controllable alternator 50, the driving sub-unit 360 is configured to control the controllable alternator 50 so that it increases the voltage of the battery 20 to reach the power required to achieve the number of predetermined injections when the required power is greater than the available power.

In the second embodiment of the vehicle 1 according to the invention, in which the vehicle 1 is devoid of a controllable alternator 50, the driving sub-unit 360 is configured to control the reduction of the torque of the engine 10 when the power required is greater than the available power.

For example, the torque requested by the driver may be limited by applying an opening instruction of the air intake flap below that corresponding to the will of the driver. This amounts to limiting the air flow entering the engine and therefore the torque achieved. Thus the engine is found on an operating point no longer requiring a large number of injections and the power required is then reduced. The invention will now be described in its implementation with reference to Figures 2 and 3.

In a preliminary step EOA, the electronic control unit 30 collects or determines, for example via a plurality of sensors, the operating speed of the motor 10, the torque of the motor 10 and the temperature of the motor 10 and determines a predetermined number of Nlreq required fuel injections, to be performed in each cylinder 12 during the same combustion cycle of the engine 10. In parallel, in a preliminary step Ε0Β, the electronic control unit 30 determines the pressure value of the fuel Pcarb at this time and an intensity value of the injector control current Ireq 120 necessary to achieve the predetermined number of fuel injections required Nlreq in the cylinders 12 via the injectors 120.

Once this predetermined number of required fuel injections Nlreq and this control current intensity value Ireq predetermined, the determination subunit 310 determines, in a step E1, from the predetermined number of injections Nlreq and of the predetermined value of the intensity of the control current lreq of the injectors 120, the required power Preq by the converter 40 to inject the gasoline into each cylinder 12.

The estimating subunit 320 then estimates, in a step E2, from the temperature Tecu of the electronic control unit 30 and the voltage VB across the power supply battery 20, the available power PdisP at the converter 40. The electronic control unit 30 then compares the required power Preq and the available power PdisP in a step E3.

When the required power is less than the available power, the electronic control unit 30 determines its temperature Tecu and compares it to a predetermined maximum value Tmax in a step E4.

When the required power Preq is lower than the available power Pdisp and when the temperature Tecu of the electronic control unit 30 is lower than a predetermined maximum temperature value Tmax, the counter CTR is set to zero and the sub-unit of injection 330 controls, in a step E5, the converter 40 so that the latter controls the injectors 120 to the predetermined value of control current intensity Ireq from the current voltage VB of the power supply battery 20 so that they inject gasoline a number of times corresponding to the predetermined number of fuel injections required Nlreq during the same combustion cycle of the engine 10.

When the temperature Tecu of the electronic control unit 30 is greater than or equal to the predetermined maximum temperature value Tmax, it is verified in a step E6A whether the counter CTR of the electronic control unit 30 is equal to the maximum value CTRmax predetermined.

If so, the reduction subunit 350 controls, in a step E6B, the motor 10 to obtain a reduction of its torque in order to reduce the required power Preq.

If not, we go to step E7 which corresponds to the case where the required power Preq determined in step E1 is greater than the available power PdisP determined in step E2.

During step E7, it is determined whether the vehicle comprises a piloted alternator 50 or not.

In the first embodiment corresponding to the presence of a controlled alternator 50, the control sub-unit 340 checks in a step E8 if the voltage VB across the battery 20 is lower than a so-called nominal voltage VBnom, corresponding to a maximum operating value of the battery 20.

If so, the control sub-unit 340 controls the driven alternator 50 so that it increases, in a step E9, the voltage VB across the battery 20 until the converter 40, which is powered by the battery 20, can provide the required power Preq or until a nominal battery voltage VBnom.

If not, the driving subunit 340 determines whether the fuel pressure Pcarb is greater than a predetermined minimum value of pressure Pmin in a step E10.

In the second embodiment corresponding to the absence of controlled alternator 50, it goes directly from step E7 to step E10 described above. In step E10, if the fuel pressure Pcarb is greater than the predetermined minimum pressure value Pmin, the piloting sub-unit 340 decreases, in a step E11, the fuel pressure in order to reduce the required power. The method resumes in step E1 (or E0).

On the other hand, if the pressure of the fuel Pcarb is lower than or equal to the predetermined minimum value of pressure Pmin, the control sub-unit 340 controls the converter 40 in a step E12 so that it realizes the predetermined number of injections. fuel required Nlreq at the minimum fuel pressure Pmin, which requires the lowest required power Preq the lowest possible, and the nominal battery voltage VBnom to provide the maximum power to the converter at minimum fuel pressure.

In this case, a counter CTR is incremented by one unit in a step E13 and then the method is repeated in step E4 making it possible to verify that the temperature Tecu of the electronic control unit 30 is lower than the predetermined maximum temperature Tmax .

Finally, it should be noted that the present invention is not limited to the examples described above and is capable of numerous variants accessible to those skilled in the art.

Claims (5)

A method for managing the direct injection of gasoline into a cylinder (12) of an internal combustion engine (10) of a motor vehicle (1), said vehicle (1) comprising a motor (10) for internal combustion, at least one power supply battery (20), an electronic control unit (30) and a dc direct current converter (40), an alternator (50) configured to be driven by the electronic control (30) and to adapt the voltage of the battery (20), said motor (10) comprising a plurality of cylinders (12), each cylinder (12) of said plurality of cylinders (12) comprising an injector (120) driven by the electronic control unit (30) via said converter (40) to inject gasoline into said cylinder (12), said method being characterized by comprising: • a step (E1 ) determining the power required for fuel injection from a predetermined number of injections and a predetermined value of intensity of the control current of the injectors (120), • a step (E2) for estimating the power available at the converter (40) from the temperature of the electronic control unit (30) and the voltage of the power supply battery (20), • a step (E3) of comparing the required power with the available power, • when the power required is lower than the available power and: - when the temperature of the electronic control unit (30) is lower than a predetermined maximum temperature value, a fuel injection step (E5) of the predetermined number of injections, the predetermined control current and the current voltage of the power supply battery (20), and the reset of a control counter, - when the temperature of the control unit the electronics (30) is greater than a predetermined maximum temperature value and when the control counter is equal to a predetermined maximum increment value, a motor torque reduction step (E6B) (10), and • when the required power is greater than the available power and that: - the fuel pressure is above a predetermined minimum pressure value, a fuel pressure lowering step (E11) to reduce the required power, - the fuel pressure is equal to the predetermined minimum pressure value, a fuel injection step (E12) of the predetermined number of injections, to the predetermined minimum pressure value and to a nominal voltage of the power supply battery (20) , and a step (E13) of incrementing the control counter, the method further comprising, on the one hand, when the power required is greater than the available power or when the control counter is different from a predetermined maximum increment value, and secondly when the voltage of the power supply battery (20) is less than a predetermined voltage rating, a step (E9) for increasing the voltage of the battery (20) until a nominal battery voltage VBnom is reached. Method according to claim 1, when the required power is lower than the available power, when the temperature of the electronic control unit (30) is greater than a predetermined maximum temperature value and when the control counter is different from a predetermined maximum increment value, then the method comprises: • when the fuel pressure is above a predetermined minimum pressure value, a step (E11) of decreasing the fuel pressure to reduce the required power, • when the fuel pressure is equal to the predetermined minimum pressure value, a fuel injection step (E12) of the predetermined number of injections at the predetermined minimum pressure value and at a nominal voltage of the supply battery an electrical step (20) and a step (E13) of incrementing the control counter. 3. Method according to any one of claims 1 and 2, wherein the predetermined number of injections is determined from the engine speed (10), its torque and its temperature. 4. Electronic control unit (30) for managing the direct injection of gasoline into a cylinder (12) of an internal combustion engine (10) of a motor vehicle (1), said vehicle (1) comprising an internal combustion engine (10), at least one power supply battery (20) and a direct current DC converter (40), said motor (10) comprising a plurality of cylinders (12), each cylinder (12) of said plurality of cylinders (12) comprising an injector (120) current-controlled by the electronic control unit (30) via said converter (40) for injecting gasoline into said cylinder (12) , said electronic control unit (30) being characterized in that it comprises: • a determination sub-unit (310) configured to determine the power required for fuel injection from a predetermined number of injections and a predetermined value d intensity of the injector control current (120), • an estimation subunit (320) configured to estimate the power available at the converter (40) from the temperature of the electronic control unit (30) and the voltage of the power supply battery (20), • an injection subunit (330) configured to inject gasoline from the predetermined number of injections, to the predetermined control current and to the current voltage of the power supply battery (20), and to zero a control counter, • a decrementing subunit (340) configured to decrease the fuel pressure to reduce the power requiredv, • a subunit (350) configured to reduce the motor torque (10); • a control subunit (360) configured to control an increase in the battery voltage (20) until a nominal battery voltage is reached; the VBnOm. A motor vehicle (1) comprising an internal combustion engine (10), at least one power supply battery (20), an electronic control unit (30) and a DC direct current converter (40), said motor (10) comprising a plurality of cylinders (12), each cylinder (12) of said plurality of cylinders (12) including an injector (120) driven by the electronic control unit via said converter (40) to injecting gasoline into said cylinder (12), said vehicle (1) being characterized in that it comprises an electronic control unit (30) according to claim 4.