WO2018220316A1

WO2018220316A1 - Supply system for an internal combustion engine

Info

Publication number: WO2018220316A1
Application number: PCT/FR2018/051231
Authority: WO
Inventors: Sébastien Potteau; Thomas COPPIN
Original assignee: Valeo Systemes De Controle Moteur
Priority date: 2017-05-31
Filing date: 2018-05-25
Publication date: 2018-12-06
Also published as: FR3067061B1; FR3067061A1

Abstract

The invention relates to a system for supplying an internal combustion engine (1), comprising at least one gas intake pipe (4) into the internal combustion engine and an electric supercharger (12) arranged on the gas intake pipe and configured to raise the pressure of the intake gases. The system further comprises an injection device (14) for injecting a liquid for cooling the intake gases, associated with the electric supercharger (12).

Description

SUPPLY SYSTEM FOR AN INTERNAL COMBUSTION ENGINE

The invention relates to the field of internal combustion engines for vehicles, and it relates more particularly to engines whose gas intake circuit is equipped with an electric supercharger.

It is known to have an electric supercharger in an intake circuit of a motor vehicle combustion engine, the electric compressor being configured to increase the pressure of the intake gas. The electric supercharging compressor conventionally comprises a wheel for compressing the air entering the compressor and an associated electrical machine which is driven in particular to drive the wheel in rotation when it is desired to raise the pressure of the intake gases. Unlike turbochargers, driven by the exhaust gas, the electric supercharger has a very short response time because it works with an electric machine. This makes it possible to increase the torque of the internal combustion engine at low speed, to compensate the response time of the turbocharger and to improve the acceleration of the motor vehicle on which the internal combustion engine equipped with the electric supercharger is mounted.

The control of the electric machine is automatic, that is to say controlled via the engine control system of the vehicle, and in particular by a control module configured to receive information relating to the operation of the vehicle and to trigger control instructions of the electrical machine of the electric supercharger as soon as a defined action is performed. For example, the actuation of an accelerator pedal can be defined as an automatic trigger condition by the control module of the electric machine of the electric supercharger.

The implementation of an overcompression of the intake gases, whether via an electric compressor, a mechanical compressor or a turbocharger, involves an increase in the temperature of the gases at the intake of the engine, which generates a particular sensitivity to the knocking phenomenon for spark ignition engines, and which can generate, for diesel engines, an increase in nitrogen oxide (NOx) emissions during the supercharging phases . Recently, car market players, faced with these temperature problems following over-compression via a turbocharger, have considered carrying out an injection of water to achieve the cooling of the intake gases. Injectors are thus arranged in the intake manifold of the engine, just upstream of the intake valves, in the immediate vicinity of the combustion chambers.

The injected water participates, by heat exchange, in the cooling of the inlet gases. In this way, the aim is to reduce the problems resulting from a potential overheating of the gases, namely the sensitivity to rattling for gasoline engines and NOx emissions for diesel engines. The invention is part of this dual context of implementing an electric supercharging compressor and a device for injecting a gas coolant, and it aims at providing an alternative to existing systems for the supply of internal combustion engines.

The invention proposes a feed system for an internal combustion engine comprising at least one gas intake pipe in the internal combustion engine and an electric supercharging compressor arranged on this gas intake pipe and configured to raising the inlet gas pressure, said system further comprising a device for injecting an intake gas coolant associated with said electric compressor. Thus, according to the invention, an injection of coolant, and in particular water, is combined with the injection of compressed air via the electric compressor. According to the invention, it is possible, particularly when the electric compressor is in operation, to drive the pump of the coolant injection device and to perform an injection of coolant, in order to cool the temperature of the coolant gases. admission and increase the density of these.

According to one characteristic of the invention, the injection device comprises at least one pump and the electric supercharging compressor comprises at least one electric machine configured to drive in rotation a compressor wheel arranged in the intake pipe, the pump being configured to be mechanically driven by the electric machine. In this way, a function integration is performed by using the electric machine of the electric supercharger to drive the pump of the injection device. The resulting decrease in the number of components is of interest in terms of cost and space. It should be noted that the function integration as just presented can be effective regardless of the form taken by the electric machine when it is configured to drive the compressor wheel in rotation and the pump is connected to this electrical machine, that the pump of the injection device consists of a centrifugal pump or a displacement pump, with fixed or variable displacement.

The objective is to increase the engine power during the activation of the electric supercharger, improve its efficiency and reduce the amount of emissions, with an injection of coolant during a given period, and for example during phases of heavy loads, or more generally during each of the activation phases of the electric compressor, this injection of coolant also making it possible to reduce the knocking sensitivity for gasoline engines and to reduce NOx in the engine. case of diesel engines.

It is particularly advantageous to combine the operation of these two systems, which find their interest in similar operating areas, that is to say at high engine loads. The electric supercharging compressor increases the gas inlet pressure and the injection device can lower the temperatures of these gases. The use of these two systems is self-regulating. The electric compressor induces a pressure difference between the inlet and the exhaust limiting the residual gases in the combustion chamber, which tends to limit the rattling, so that the coolant requirements are reduced. Similarly, for a given torque, the injection of coolant reduces rattling and increases the density of the admitted gases, which helps to lower the power that must provide the electric compressor.

According to various features of the invention, taken alone or in combination, provision may be made for:

the injection device comprises, in addition to the pump, a coolant storage tank, an injection nozzle opening on the intake pipe to form a zone for injecting the cooling liquid, and a cooling circuit; injection capable of transporting the coolant from the storage tank to the injection nozzle, via the pump; the pump is a reversible volumetric pump; such a pump makes it possible to drain the remaining coolant inside the injection circuit to the storage tank, especially when the vehicle is stopped;

- The injection device comprises a return circuit to the storage tank, optionally associated with a pressure regulator;

the device comprises at least one pressure regulating valve arranged on the injection circuit; the pressure control valve may in particular be positioned on the injection circuit downstream of the pump, which allows a return to the storage tank of the coolant which is not used; the injection zone of the injection device is offset with respect to the electric supercharging compressor;

the injection zone is downstream of the electric supercharger;

- The injection zone of the injection device may be distributed in several regions distant from each other, if necessary upstream and downstream of the electric supercharger;

the injection zone is integrated in the electric supercharger; the injection zone may in particular be carried out in the volute of the electric supercharger;

According to a series of features of the invention, taken alone or in combination, it is expected that the connections between the electric machine, the pump and the electric compressor wheel are rigid connections, and that, if appropriate:

the electric machine, the pump and the wheel of the electric compressor are arranged in a coaxial configuration;

the pump is interposed between the electric machine and the electric compressor wheel;

the pump is disposed opposite to the wheel of the electric compressor with respect to the electric machine; the pump is arranged so that the wheel of the electric compressor is interposed between the electric machine and the pump;

the electric machine, the pump and the electric compressor wheel are arranged in a non-coaxial configuration; non-coaxial configuration means a configuration of the components relative to each other using at least one belt, a chain or a gear stage; the gear stage can in particular be configured to form a speed reduction means arranged between the electric machine and the pump.

According to another series of features of the invention, taken alone or in combination, at least one of the connections between the electric machine, the pump and the wheel of the electric compressor comprises a clutch, and that if appropriate:

- The electric machine is rigidly connected to the pump and the pump is connected to the compressor wheel via a clutch; such an arrangement offers the possibility, by adjusting the state of the clutch in particular, to inject a given amount of coolant without using the electric supercharger; this may especially be useful in cases where it is detected a temperature of the intake gases going beyond a threshold temperature value;

- The electric machine is rigidly connected to the wheel of the electric compressor and the pump is connected to the electric machine via a clutch; such an arrangement offers the possibility, by playing on the condition of the clutch in particular, to use the electric compressor without injecting coolant, and therefore to take advantage of the full power deliverable by the electric machine to compress the gases when the temperature of these gases makes superfluous the injection of coolant, or when a failure of the injection device is detected, this failure may be a mechanical defect of the pump for example or in a lack of coolant in the tank;

the electric machine is linked to the pump by a first clutch and to the compressor wheel by a second clutch; it is understood that such an arrangement, more complex to control, allows to control the compression of the inlet gases and the cooling thereof by compiling the previously described advantages. The fuel system may comprise a turbocharger arranged between a gas exhaust pipe of the internal combustion engine and the gas intake pipe of the engine. The injection nozzle may be disposed upstream of the electric supercharger, between the electric compressor and the turbocharger. In the case of an electric supercharging compressor arranged downstream of a turbocharger, an injection of coolant upstream of the electric compressor makes it possible to cool the air arriving on the wheel of the electric compressor and thus makes it possible to protect the electric compressor high temperatures and slightly lower the power required for a given compression rate and flow, without the need to add a heat exchanger, and therefore with a smaller footprint. The lifespan of the electric compressor is increased accordingly. It is understood that in this case, it can provide a protection of the electric compressor vis-à-vis the coolant droplets, and for example by providing a particular coating of the compressor wheel.

The invention also relates to a method for controlling the power supply of an internal combustion engine of a vehicle during which a first control command of an electric supercharger and a second control command of a supercharger are generated. device for injecting a coolant into the intake duct of the internal combustion engine.

In the case where the pump of the injection device is rigidly mounted on the output shaft of the electric machine rotating the wheel of the electric compressor, the first control instruction may consist of an activation command of the electric machine and the second control command may consist of an activation command of a pressure regulating valve controlling the circulation of the coolant between the pump and a storage tank or an injection nozzle. In the case where a clutch is provided between the electric machine and the pump or the wheel of the electric compressor, each control command may consist of an activation command of the same electrical machine and at least one control command may consist of in addition to an activation command of a clutch arranged between said electric machine and a specific component of the electric supercharger, for example the wheel, or the coolant injection device, for example the pump. According to a characteristic of a method according to one aspect of the invention, it is possible to consider an intake gas temperature value with respect to a threshold value, beyond which a control command consisting of a control command is generated. activation of the electric machine, and a control command consisting of a control of the pressure regulating valve controlling the circulation of coolant or a clutch arranged between the electric machine and a specific component of the injection device. cooling liquid.

Other variables could be considered for the activation of the coolant injection, such as, for example, the inlet pressure, the engine load reference or the measured knock level.

Other characteristics, details and advantages of the invention will emerge more clearly on reading the description given below as an indication in relation to drawings in which:

FIG. 1 illustrates an exemplary embodiment of an internal combustion engine equipped on its intake circuit with an electric supercharging compressor, disposed downstream of a turbocharger, and with an injection device of a cooling liquid ;

FIG. 2 is a detail of the gas intake circuit of an internal combustion engine, schematically illustrating the electric compressor and the device for injecting a cooling liquid according to a first arrangement, in which the coolant is injected downstream of the electric compressor;

FIG. 3 is a detail of the gas intake circuit of an internal combustion engine, schematically illustrating the electric compressor and the device for injecting a cooling liquid according to a second arrangement, in which the coolant is injected upstream of the electric compressor; FIG. 4 is a detail of the gas intake circuit of an internal combustion engine, schematically illustrating the electric compressor and the device for injecting a cooling liquid according to a third arrangement, in which the coolant is injected into the electric compressor;

- Figures 5 to 7 illustrate different arrangements of a pump of the injection device, with respect to the electric machine and the wheel of the electric compressor; and FIG. 8 is a flowchart illustrating an embodiment of a method for controlling the power supply of the heat engine, in the case of the arrangement illustrated in FIG. 7, in which the pump is linked to the electric machine via a clutch and in which the compressor wheel is linked to the electric machine also by a clutch.

As a reminder, the invention relates to a supply system for an internal combustion engine in which an electric supercharging compressor and a device for injecting an intake gas coolant of this engine are associated.

By way of example, FIG. 1 shows an internal combustion engine 1 on which a supply system according to one embodiment of the invention is applied. The internal combustion engine 1 comprises a motor unit 2 defining combustion chambers provided with pistons which rotate an output shaft. The combustion chambers of the engine block 2 are connected via an intake manifold 3 to a gas intake pipe 4, in particular fresh air taken from outside the vehicle, and via an exhaust manifold 5 an exhaust pipe 6 of the flue gases during combustion, or exhaust gas.

In the example illustrated in FIG. 1, the internal combustion engine 1 is a turbocharged engine in which a turbocharger 7 is formed by the cooperation of a compressor 8, arranged on the intake pipe 4, and a turbine 10, placed on the exhaust pipe 6 so as to recover a portion of the energy of the exhaust gas and to rotate the compressor 8. In particular, the compressor 8 and the turbine 10 can be mounted on a common shaft 810 .

Heat exchangers, not shown here, can be arranged on the intake pipe and a gas after-treatment system 9 can be arranged on the exhaust pipe.

According to the invention, the feed system of the internal combustion engine comprises an electric supercharging compressor 12 arranged on the gas intake pipe 4 and configured to raise the pressure of the intake gases, and this electric supercharging compressor is associated with an injection device 14 of an intake gas coolant. As will be detailed below, the injection device is configured to allow an injection of coolant combined with the production of compressed air via the electric compressor.

The electric compressor 12 comprises at least one electric machine 16 configured to rotate a compressor wheel 18 arranged in the intake pipe 4. It is understood that the control of the electric machine 16 allows the rotation of the wheel to the the interior of the intake pipe 4 and the compression as a result of the gases flowing in the intake pipe 4.

The intake pipe 4 comprises a bypass circuit 20 on which is disposed a control valve 22, for modulating the proportion of admitted gas to be compressed via the electric supercharger.

The injection device 14 comprises a pump 24, a storage tank 26 of coolant, an injection nozzle 28 opening on the intake pipe 4 to form a coolant injection zone, and a circuit injection 30 capable of transporting the cooling liquid from the storage tank 26 to the injection nozzle 28 via the pump 24.

It is understood that according to the invention, the coolant injection device 14 is associated with the operation of the electric supercharging compressor 12. In the illustrated examples, a mechanical connection is arranged between the electric machine, the pump and the wheel of the electric compressor. The pump 24 of the injection device 14 is thus configured to be driven mechanically by the electric machine 16 of the electric compressor 12, via at least one drive arm. Different arrangements will be described below illustrating this combination characteristic of the injection device and the electric supercharging compressor. The injection device 14 is capable of injecting into the intake pipe 4 a cooling liquid, which may in particular consist of water, it being understood that a particular mixture could be injected in that it makes it possible to reduce rattling, and for example a mixture of water and methanol. In the following, the term coolant will be used to cover these different possibilities and other variants having equivalent effects. The pump 24 of the injection device 14 consists of a centrifugal pump or a displacement pump, with fixed or variable displacement. In particular, it can be provided that the injection device comprises a reversible volumetric pump.

Furthermore, the injection device 14 comprises at least one pressure regulating valve 32 arranged on the injection circuit 30, here downstream of the pump without this being limiting to this aspect of the invention, and which allows to control the supply of coolant, in particular according to the state of operation of the electric supercharger.

The injection device 14 may further comprise a tank return circuit, not shown here, associated optionally with the pressure regulating valve 32.

FIGS. 2 to 4 show several different arrangements which differ in the position of the injection nozzle 28 of the injection device on the intake pipe 4 and therefore in the position of the liquid injection zone. cooling.

In FIGS. 2 and 3, the injection zone is offset with respect to the electric compressor 12, and the injection nozzle 28 opens onto the inlet pipe 4 downstream (FIG. 2) or upstream (FIG. electric supercharger 12.

In the case illustrated in FIG. 1, where a turbocharger 7 is disposed on the gas intake pipe 4, the coolant injection nozzle 28 may in particular be arranged upstream of the electric compressor 12, between the electric compressor and the turbocharger 7 · This allows to cool the air arriving on the wheel 18 of the electric compressor without the need to add a heat exchanger, and therefore with a smaller footprint.

The system may comprise a protection device, not shown in the figures, of the electric compressor vis-à-vis the coolant droplets, and for example by providing a particular coating of the compressor wheel.

In FIG. 4, the injection zone is integrated in the electric compressor, the coolant injection nozzle 28 opening into the volute 34 of the electric compressor 12. As previously, it is possible to provide in this case a particular coating of the components of the electric compressor to prevent their potential deterioration by the projection of drops of coolant. In variant not shown, it can be provided that the injection zone of the injection device can be distributed in several regions distant from each other, possibly upstream and downstream of the electric compressor, with a plurality of injection nozzles fed by different injection circuits connected to the pump. As has been mentioned above, the feed system according to the invention comprises a coolant injection device 14 associated with the operation of the electric supercharging compressor 12. In the illustrated examples, a mechanical connection is arranged between the electric machine, pump and electric compressor wheel.

In particular, it is possible to provide between these components rigid connections, that is to say having one or more arms secured to each of their ends of one of the components, so that the activation of the electrical machine 16 generates the simultaneous driving of the pump 24 and the wheel 18 of the electric compressor or provide disengageable connections, allowing the drive by the electric machine of one and / or the other of the pump and the wheel of the electric compressor according to the operating situations encountered.

FIGS. 1 to 5 show a first particular arrangement in that the electric machine, the pump and the wheel of the electric compressor are arranged in a coaxial configuration. More particularly, in FIGS. 2 to 5, the pump 24 of the injection device 14 is mounted on a drive arm 36 arranged between the machine and the wheel of the electric compressor so that the pump 24 is interposed between the electric machine 16 and the wheel 18 of the electric compressor. It is possible to provide, as shown diagrammatically in FIG. 1, a variant in this first coaxial configuration according to which the pump 24 is disposed opposite the wheel 18 of the electric compressor with respect to the electric machine 16, so that that the electric machine, the pump and the wheel of the electric compressor are arranged in a coaxial configuration, with the electric machine 16 interposed between the pump 24 and the wheel 18 of the electric compressor. In this variant, one can provide two separate drive arms driven simultaneously by the electric machine and respectively carrying the pump of the injection device and the wheel of the electric compressor. As illustrated in FIG. 5, the first arrangement according to which the electric machine, the pump and the wheel of the electric compressor are arranged in a coaxial configuration can be implemented with at least one clutch 40 placed between two of these components, to allow the drive by the electric machine of one of the components of the electric compressor wheel or the pump without the other component being driven. By way of example illustrated in FIG. 5, it is understood that the start-up of the electrical machine systematically drives the pump, and therefore the injection of coolant into the intake circuit if at the same time the Pressure regulation is controlled accordingly, while it can be decorrelated from the drive of the electric compressor wheel. By cons, in this particular arrangement, the drive of the electric compressor wheel systematically drives the pump of the injection device, and therefore the injection of coolant in the intake circuit if in the same time the pressure regulating valve is controlled accordingly. Such an arrangement thus makes it possible, by adjusting the condition of the clutch in particular, to inject a given quantity of coolant without using the electric supercharging compressor, which can be useful in cases of occasional cooling to the occasion of the detection of a temperature of the intake gases exceeding a threshold temperature value, it being understood that the mention of this criterion is not limiting of the invention and that any other value testifying to a condition requiring water injection could be monitored and measured.

In FIGS. 6 and 7, there are illustrated other possible arrangements of the invention, in which it is notable that, contrary to what has been described above, the components that are the pump, the electric machine and the compressor wheel electrical devices are arranged in a non-coaxial configuration, that is to say a configuration of the components relative to each other using at least one belt, a chain or a gear stage. In the illustrated examples, a gear stage 42 is shown, and it should be noted that this arrangement can in particular allow the formation of a speed reducing means arranged between the electric machine and the pump. In FIG. 6, the electric machine 16 is rigidly connected to the wheel 18 of the electric compressor via a first drive arm 44 and the pump 24 is connected to the electric machine 16 on the one hand by a stage gear 42 allowing a reduction in speed, and secondly via a clutch 40. Such an arrangement offers the possibility, by adjusting the state of the clutch in particular, to use the electric compressor without injecting coolant.

In FIG. 7, the electrical machine 16 is connected to the pump 24 on the one hand by a gear stage 42 allowing a speed reduction, and on the other hand by a first clutch 46, and this electrical machine 16 is linked at wheel 18 of the compressor by a second clutch 48. It is understood that such an arrangement, more complex to control, allows to control the compression of the inlet gases and the cooling thereof by compiling the advantages described above.

It is understood from the foregoing that other arrangements could be envisaged, combining axial or non-coaxial configurations with rigid links or having clutches.

An example of a driving method 100 of the supply of an internal combustion engine according to the invention will now be described, with reference to the particular arrangement of a feed system according to one aspect of the invention illustrated. in Figure 7 · It will be understood that what will be described later can be applied to other arrangements of supply systems according to the invention without particular difficulty.

The method for controlling the supply of an internal combustion engine according to the invention is carried out when it is desired to inject a cooling liquid into an intake pipe of this engine, which is also equipped with an electric compressor. during a defined period, for example during the activation phases of the electric compressor.

The control method 100 starts with a request for the injection of coolant 101 and / or with a request for activation of the electric supercharger 102. The request can notably come from a control instruction of a control module. of the vehicle, depending on the exceeding of defined threshold values.

By way of non-limiting example, it is possible, for example, to consider a temperature value of the intake gases and to compare it with respect to a threshold value, beyond which a control instruction is generated simultaneously or at least one consisting of an activation command of the electric machine and a control command consisting of a control of the pressure regulating valve controlling the circulation of the coolant and / or a clutch arranged between the electric machine and a specific component of the coolant injection device.

With regard to the request for the injection of coolant 101, it is first decided, following a state verification step 103 of the coolant injection device 14, if a defined quantity of coolant can be projected into the intake duct. In the case of a negative response ("N"), a control instruction relating to an opening step 104 of the first clutch 46 arranged between the pump 24 and the electrical machine 16 is generated, so that the electric machine is cut off. and the pump, and therefore the coolant injection device 14 of the electric machine of the supercharging electric compressor 12. The electric machine 16 can be activated to drive the wheel 18 of the electric compressor independently of the liquid injection device cooling.

In the case of a positive response ("0"), a control instruction relating to a closing step 105 of this first clutch 46 arranged between the pump 24 and the electrical machine 16 is generated, so that the electrical machine is coupled and the pump, and therefore the coolant injection device 14 with the electric machine of the supercharging electric compressor 12. The projection of coolant is therefore possible as soon as it is activated. electric machine 16.

At the end of this closing step 105 of the first clutch 46, an activation request control step 106 of the electric supercharger 12 is performed, during which it is checked whether the activation conditions of the compressor are met.

If this is the case ("O"), we find ourselves in the case of a control command of a vehicle control module for a request for activation of the electric supercharger 102 as it has been mentioned above and will be discussed in more detail below in this part of the process.

If this is not the case ("N"), that is to say if the compressor activation conditions are not fulfilled, the control module generates a command instruction relating to a control step 107. of the electric machine 16 at the speed required by the injection of cooling liquid. Since the electric supercharger is not intended in this case to be activated, the electric machine is supplied at a level just enough to turn the pump 24.

This piloting step ends when a request to stop the injection of coolant is generated by the control module or is performed by the user of the vehicle for example. A test step 108 is thus performed in real time or at regular intervals as soon as the driving step 107 of the electrical machine is implemented, to ensure the existence ("O") or not ( "N") of a request to stop the injection of coolant. If such a request does not exist, the driving step continues in a loop, while that if such a request exists, a command instruction relating to an opening step 104 of the first clutch 46 arranged between the pump 24 and the electric machine 16 is generated, so that, as it may have been previously described in the in the case where the injection of coolant is not operational, the electric machine and the pump, and therefore the coolant injection device 14 of the electric machine of the electric supercharger 12, are decoupled.

Furthermore, when a request for activation of the electric supercharger 102 is identified, or when the conditions of this activation are considered fulfilled following the activation request control step 106 of the electric supercharger 12, a control instruction relating to a closing step 109 of the second clutch 48 arranged between the wheel 18 of the compressor and the electric machine 16 is generated, so that the electric machine and the wheel of the electric compressor are coupled.

In this case, the control module generates a control instruction relating to a driving step 110 of the electric machine 16 at the speed required by the operation of the electric supercharger. In order to ensure the compression of the gases flowing in the intake duct, the electric machine can be activated at full load to rotate the compressor wheel. In this state, the load of the electric machine is sufficient to simultaneously rotate the pump 24 if the first clutch 46 is closed simultaneously with the second clutch 48.

This control step 110 ends when a request to stop operation of the electric supercharger is generated by the control module or is performed by the user of the vehicle for example. A test step 111 is thus performed in real time or at regular intervals when the driving step 110 of the electrical machine is implemented, to ensure the existence ("O") or not ( "N") of a request to stop the operation of the electric supercharger. If such a request does not exist, the driving step 110 continues in a loop, whereas if such a request exists, a command instruction relating to an opening step 112 of the second clutch 48 arranged between the wheel 18 and the electrical machine 16 is generated, so that the electric machine and the wheel of the electric compressor are decoupled. Only the pump 24 is then activated by the rotation of the electric machine, since the first clutch 46 is always closed. It follows from the foregoing that a method of controlling the supply of an internal combustion engine of a vehicle according to the invention comprises a step during which a first control command lCi of a compressor is generated. an electric supercharger and a second control command IC2 of a device for injecting a coolant into the intake duct of the internal combustion engine.

In the practical case just described, where a clutch is provided between the electric machine and the pump or the wheel of the electric compressor, it is understood that each control instruction IC 1, IC 2 comprises an activation command of the electric machine. at a specific operating speed of the compressor pump or wheel and at least one control instruction may further consist of a clutch activation control arranged between said electric machine and a specific component of the electric supercharger for example the wheel, or the coolant injection device, for example the pump.

It is understood that in arrangements in which the compressor wheel and / or the pump of the injection device is rigidly mounted on the output shaft of the electric machine, without an intermediate clutch, the first control command lCi and / or the second control command IC2 may consist of an activation command identical to that described above with the opening and closing phases of the clutches that are deleted. Moreover, in each case where the pump rotates, the second control command IC2 may be associated with an activation command of the pressure regulating valve controlling the circulation of the coolant between the pump and the storage tank or between the pump and the injection nozzle, since the valve is controllable and not purely massive. It will be understood from the foregoing that the feed system according to the invention is advantageous in that it comprises a coolant injection device associated with an electric supercharger, in order to combine the projection of liquid for cooling the gases in the intake pipe and the compression of these gases before their admission into the engine block. According to the invention, it is possible, especially when the electric compressor is in operation, to drive the pump of the coolant injection device and to perform an injection of coolant, to cool the temperature of the inlet gas and increase the density thereof.

This advantage is all the more interesting in arrangements in which components of the coolant injection device and the electric supercharger are driven by a common actuator. However, as has been previously described, it should be noted that the present invention also covers arrangements without mechanical connection between the electric machine of the supercharger and the pump, which is then driven by a separate actuator, since the coolant injection device is controlled according to the control of the electric compressor.

Of course, various modifications can be made by those skilled in the art to the power system without departing from the context of the invention, it being understood that the invention can not be limited to the embodiment specifically described in this document, and that it extends in particular to all equivalent means and to any technically operating combination of these means, since a fuel system of an internal combustion engine comprises an electric supercharger arranged on an intake pipe of gas and a device for injecting an intake gas coolant associated with this electric compressor.

Claims

A fuel system of an internal combustion engine (1) comprising at least one gas intake pipe (4) in the internal combustion engine and an electric supercharger (12) arranged on said intake pipe of gas and configured to raise the intake gas pressure, said system further comprising an injection gas coolant (14) associated with said electric compressor (12).

Supply system according to claim 1, wherein the injection device (14) comprises at least one pump (24) and wherein the electric supercharger (12) comprises at least one electric machine (16) configured to drive in rotation a compressor wheel (18) arranged in the intake duct (4), the pump being configured to be driven mechanically by the electric machine.

Feeding system according to claim 2, characterized in that the pump (24) is a reversible displacement pump.

Supply system according to Claim 2 or 3, characterized in that the injection device (14) comprises, in addition to the pump (24), a storage tank (26) for cooling liquid, an injection nozzle ( 28) opening on the intake pipe (4) to form a coolant injection zone, and an injection circuit (30) capable of transporting the coolant from the storage tank to the nozzle injection, via the pump.

Supply system according to claim 4, characterized in that the injection device (14) comprises at least one pressure regulating valve (32) arranged on the injection circuit (30).

Fuel system according to claim 4 or 5, characterized in that the injection zone of the injection device (14) is offset relative to the electric supercharger (12).

Fuel system according to claim 4 or 5, characterized in that injection is integrated in the electric supercharger (12).

8. Fuel system according to one of claims 2 to 7, characterized in that the connections between the electric machine (16), the pump (24) and the wheel (18) of the electric compressor are rigid connections.

9. Fuel system according to one of claims 2 to 7, characterized in that at least one of the connections between the electric machine (16), the pump (24) and the wheel (18) of the electric compressor comprises a clutch (40, 46, 48).

10. Fuel system according to the preceding claim, characterized in that the electric machine (16) is connected to the pump (24) by a first clutch (46) and the wheel (18) of the compressor by a second clutch ( 48).

11. Fuel system according to one of the preceding claims, characterized in that it comprises a turbocharger (7) arranged between an exhaust pipe (6) of the internal combustion engine gas (1) and the fuel pipe. admission (4) of the gases of this engine.

12. Fuel system according to the preceding claim, in combination with claim 4, characterized in that the injection nozzle (28) is disposed upstream of the electric supercharger (12), between the electric supercharger and the supercharger. the turbocharger (7).

13- A method for controlling the supply of an internal combustion engine of a vehicle during which a first control command (lCi) of an electric supercharging compressor (12) and a second control command ( IC2) of a device (14) for injecting a cooling liquid into the intake pipe (4) of the internal combustion engine (1), a pump (24) of the injection device being mounted rigidly on a drive shaft of the electric machine (16) further rotating the wheel (18) of the electric compressor, the first control command (1Ci) consisting of an activation command of the electric machine (16) and the second control command (IC2) consisting of an activation command of a pressure regulating valve (32) controlling the circulation of coolant between the pump and a storage tank (26) or between the pump and a nozzle injection (28).

14- A method for controlling the supply of an internal combustion engine of a vehicle during which a first control instruction (lCi) of a electric supercharger (12) and a second control command (IC2) of an injection device (14) for a coolant in the intake pipe (4) of the internal combustion engine, each control (IC1, IC2) consisting of an activation command of the same electrical machine (16) and at least one control command further comprising an activation control of a clutch (40, 46, 48) arranged between said electric machine and a specific component of the electric supercharger or the coolant injection device.