EP4112913A1 - Motor vehicle with internal combustion engine comprising a system for recovering water from the exhaust gas - Google Patents

Abstract

[Motor vehicle (V, V') comprising a system for recovering water in the exhaust gases including a circuit for supplying the engine (32, 35, 350) with recovered water, the said system comprising:- a chamber condensation (30) of an outside air/exhaust gas enthalpy mixture to extract the water therefrom, arranged in the exhaust line downstream of the exhaust gas post-treatment part, - a collection and delivery of outside air (40, 40', 40", 43, 44), having a fluidic connection with the exhaust line downstream of the exhaust gas after-treatment part and upstream of said condensation chamber, and- at least two separate reservoirs (301, 302) for storing recovered water, one constituting a primary reservoir (301) located in or downstream of said condensation chamber and which supplies the water which will supply the motor, and the other constituting a secondary tank (302) located upstream of the condensation chamber, and- circulation means (33) for the recovered water allowing at least one circulation of the water from said primary tank to said secondary tank and from said primary tank to the recovered water engine supply circuit.

Description

[The invention relates to a motor vehicle comprising a system for recovering water from the exhaust gases of an internal combustion engine by enthalpy air/exhaust gas mixing, with storage and management of the extracted water. It also relates to a process for recovering water from the exhaust gases passing through the exhaust line of an internal combustion engine, including supplying the engine with recovered water.

The heat engines of motor vehicles, in particular gasoline-powered ones with high specific power, can be limited on the one hand by the thermal resistance of the constituent parts of the exhaust system evacuating the combustion gases, and on the other hand by the appearance knocking in their combustion chambers.

One of the known ways to solve these problems, while maintaining the pollution control performance, is the injection of water into the air intake. In fact, the injection of water in liquid form does not provide additional energy for combustion. The water injected in liquid form adds specific heat capacity (also called specific heat or specific heat) to the fuel/intake air mixture, and its latent heat of vaporization (also called enthalpy of vaporization). This results in a drop in the combustion temperature, which is positive against knocking, and a drop in the temperature of the exhaust gases, which is favorable to the thermal resistance of the component parts of the exhaust system.

• un compromis taille de réservoir / autonomie acceptable à trouver,
• le besoin d'un système de remplissage dédié,
• le besoin d'eau déminéralisée et la nécessité de faire la recharge du réservoir en eau déminéralisée régulièrement, avec intervention du conducteur ou d'un opérateur pour la recharge,
• le besoin de maintien de la qualité de l'eau dans le temps par un traitement adéquat contre le croupissement,
• le besoin d'un système de dégel, pour un fonctionnement par temps froid.

Existing water injection systems mainly operate by being recharged by supplying water from the trade via filling a dedicated supply circuit.
This embodiment in particular poses the following problems:

• a compromise tank size / acceptable autonomy to be found,
• the need for a dedicated filling system,
• the need for demineralised water and the need to refill the tank with demineralised water regularly, with the intervention of the driver or an operator for refilling,
• the need to maintain water quality over time through adequate treatment against stagnation,
• the need for a defrost system, for cold weather operation.

The disadvantages of this type of injection system with water refill is that it is restrictive for the user of the vehicle because it is not autonomous, and to be relatively expensive (high initial additional cost and an additional cost of use for the refills with demineralized water), and this for a system which in the end will not always be available, which also leads to a loss of engine performance.

As another known solution, the recovery of water by drying the outside air by an air conditioning system has been proposed. Its major drawback is to be dependent on external conditions, for example in a dry atmosphere, this system can be limited or even inoperative.

Another water recovery solution could be envisaged by recovery of rainwater, but it also has the major drawback of a lack of availability of water to condense for a given external condition, in particular in the event of summer drought or in very cold and/or desert climates.

According to another solution, the water injected is water recovered from the exhaust gases emitted by a combustion engine of a motor vehicle, following the combustion of the fuel. In this solution, a heat exchanger, also called a condenser, is used directly in the exhaust gas duct, to condense the water vapor contained in said gases. Such a system has for example been described in the patent application WO2017174254A1 .
This type of system requires that the condenser/cooler itself be supplied with cold fluid. Independently of the high cost of this device, it therefore has the disadvantage of adding cooling needs additional and considerable on calenders already well loaded with coolers (RAS (Supercharged Air Cooler) / Main radiator / Air conditioning system exchanger / aerostat, etc.).

All these systems for injecting water into the combustion circuit have drawbacks, in particular those mentioned above, although these systems have shown interest whatever the place of addition of water, whether directly in the combustion chamber or whether upstream of the combustion chamber in the air intake ducts.

The invention aims to provide a system for injecting water into an engine, whether directly into the combustion chamber or whether upstream of the combustion chamber, in the air intake ducts, which does not have, at least in large part, the drawbacks of the systems of the prior art.

• une chambre de condensation d'un mélange enthalpique air extérieur/gaz d'échappement pour en extraire l'eau , disposée sur la ligne d'échappement en aval de la partie de post-traitement des gaz d'échappement,
• un système de captation et d'acheminement d'air extérieur, ayant une connexion fluidique avec la ligne d'échappement en aval de la partie de post-traitement des gaz d'échappement et en amont de ladite chambre de condensation, et
• au moins deux réservoirs distincts pour le stockage de l'eau récupérée, l'un constituant un réservoir primaire situé dans ou en aval de ladite chambre de condensation et qui fournit l'eau qui alimentera le moteur, et l'autre constituant un réservoir secondaire situé en amont de la chambre de condensation, et
• des moyens de circulation de l'eau récupérée permettant au moins une circulation de l'eau dudit réservoir primaire vers ledit réservoir secondaire et dudit réservoir primaire vers le circuit d'alimentation du moteur en eau récupérée.

To this end, the invention proposes a motor vehicle comprising a powertrain comprising at least one internal combustion engine, an exhaust line with a part comprising means for post-treatment of the exhaust gases produced by the engine, a system for recovering water from the exhaust gases including a circuit for supplying water recovered from the engine,
characterized in that said system for recovering water in the exhaust gases comprises:

• a chamber for condensing an enthalpy outside air/exhaust gas mixture in order to extract the water therefrom, arranged on the exhaust line downstream of the exhaust gas post-treatment part,
• a system for capturing and conveying outside air, having a fluidic connection with the exhaust line downstream of the exhaust gas post-treatment part and upstream of said condensation chamber, and
• at least two separate tanks for storing the recovered water, one constituting a primary tank located in or downstream of said condensation chamber and which supplies the water which will supply the engine, and the other constituting a secondary tank located upstream of the condensation chamber, and
• means for circulating the recovered water allowing at least one circulation of the water from said primary reservoir to said secondary reservoir and from said primary reservoir to the circuit for supplying the engine with recovered water.

The notions of "upstream" and "downstream" relate to the direction of circulation of the exhaust gases in the exhaust line and the condensation chamber, the gases circulating from the outlet of the combustion chamber of the engine towards the open end of the exhaust pipe expelling said gases (generally towards the rear of the vehicle).

The powertrain comprises at least one internal combustion engine, which can be naturally aspirated or turbocharged (supercharged), assisted or not by electric motors. In addition, one or more computers can make it possible to operate the entire powertrain.

The means for post-treatment of the exhaust gases produced by the engine, resulting from the combustion of the fuel/intake air mixture, may comprise a catalytic converter to clean up the exhaust gases and preferably also a particulate filter to treat the fine particles present in the exhaust gases.

The supply of outside air which is at a cool temperature, much lower than that of the exhaust gases which are hot, makes it possible to carry out/control the enthalpy gaseous mixture as explained later in detail when describing the examples. and drawings.

The circuit for supplying the engine with recovered water may comprise means for introducing recovered water into the engine, such as one or more injectors, for example an injector rail.

According to an advantageous embodiment of the invention, said secondary reservoir has a capacity greater than that of the primary reservoir, in order to be able to transfer therein at least all of the water contained in the primary reservoir. Furthermore, it should preferably be insensitive to the solidification of water. In addition, said secondary tank, also called "hot tank", must be in a hot zone so that sufficient temperatures prevail there to allow the liquefaction and evaporation of the water it contains. It is preferably located in a hot part of the exhaust line when driving (of the vehicle). Thus this secondary tank allows at least to drain the water accumulated in said tank primary, also called "cold tank", in particular at the end of driving so as to avoid the problem of managing the frost in said cold tank, and it can also avoid the stagnation of the recovered water.

According to a particular embodiment of the invention, the exhaust line comprises a silencer, and said silencer constitutes said secondary tank.

Preferably according to the invention, said water recovery system comprises a water pump allowing at least the circulation of the water recovered from the primary tank to the secondary tank and also from the primary tank to the engine supply circuit in reclaimed water.

Advantageously according to the invention, said water recovery system comprises means for circulating the recovered water allowing water to circulate in both directions between said primary reservoir and said secondary reservoir. Also advantageously, said system comprises means for circulating the recovered water allowing water to circulate in both directions between said primary tank and the circuit for supplying the engine with recovered water, in order to be able to drain the circuit if necessary. In particular, said means allowing this two-way circulation comprise a self-priming water pump.

The condensation chamber is intended to receive the mixture of exhaust gases and fresh air. This is where the condensation reaction of the mixture thus formed takes place. Preferably according to the invention, said condensation chamber comprises at least one metal condensation support, making it possible to promote the condensation of the water contained in the gases by the formation of droplets on its cold metal walls, for example one or more grids fine mesh metal.

According to a preferred embodiment of the invention, said water recovery system comprises a mixer downstream of the connection of the system for capturing and conveying outside air to the exhaust line and upstream of the chamber condensation, to homogenize the exhaust gases and the outside air forming the enthalpy mixture that will enter the condensation chamber.

According to a particular embodiment of the invention, said system for capturing and conveying outside air comprises means for controlling the flow rate of the flow of outside air mixing with the exhaust gases, for example a controllable valve.

In particular, said system for capturing and conveying outside air comprises a scoop, and if necessary the scoop is equipped with a means for controlling the flow rate of the flow of outside air mixing with the exhaust gases, by example a controllable valve.

According to another particular embodiment of the invention, said system for capturing and conveying outside air comprises an air pump allowing the supply of air and the control of the flow rate of the flow of outside air mixing with the exhaust gas. Advantageously, this air pump can be controlled electrically, in order to be able to generate an enthalpy mixture even if the vehicle is not moving, the engine being running, or is driving at low speeds.

According to a particular embodiment of the invention, said water recovery system comprises means for controlling the flow rate of the flow of exhaust gases mixing with the outside air to form the enthalpy mixture. In other words, said system comprises a bypass, for example a controllable valve.

Preferably, said system comprises means for managing the production of water, making it possible to adjust the quantity of water produced on demand, in particular according to the meteorological conditions (temperature, hygrometry) and/or the type of route of the vehicle. , and/or the formulation of the fuel used, and to supervise the minimum quantity of water to be kept in reserve in the primary tank.

In particular, said system comprises a supervisor of a minimum quantity of water constituting a water reserve in the primary reservoir, in conjunction with a water production model, in particular as a function of parameters relating to meteorological conditions, and /or to the characteristics of the fuel and/or of the intake air and/or of the exhaust gases and/or of the outside air forming the enthalpy mixture, and/or of the road profile through which the vehicle travels

In particular, the water recovery system according to the invention comprises sensors, probes, computers and, where appropriate, means of communication with or without wires necessary for its operation. In particular, the various controllable elements can be controlled by dedicated computers or by those of the powertrain.

• mélanger les gaz d'échappement émis par le moteur à de l'air extérieur pour former un mélange enthalpique, ledit air extérieur étant apporté par un système de captation et d'acheminement d'air extérieur en connexion fluidique avec la ligne d'échappement en aval des éléments de post-traitement (et assez loin pour profiter des échanges thermiques qui ont lieu lors du cheminement des gaz d'échappement dans la ligne), et en amont d'une chambre de condensation, puis
• acheminer et condenser ledit mélange enthalpique air extérieur /gaz d'échappement dans une chambre de condensation pour en extraire l'eau par condensation sur des supports de condensation, ladite chambre étant disposée sur la ligne d'échappement en aval d'une partie chaude de ladite ligne d'échappement, et
• récupérer l'eau ainsi condensée dans un réservoir primaire, situé dans ou en aval de ladite chambre de condensation, reliée au circuit d'alimentation du moteur en eau récupérée afin d'alimenter en eau récupérée ledit moteur (par injection de l'eau dans le moteur),
• vidanger, en particulier par pompage, en fonction d'une réserve d'eau donnée conservée dans le réservoir primaire, ou en totalité si nécessaire, dudit réservoir primaire vers un réservoir secondaire situé en amont de la chambre de condensation, et avant la connexion entre le système de captation et d'acheminement de l'air extérieur et la ligne d'échappement, selon des événements programmés ou détectés, notamment périodiquement lors d'arrêts du moteur ou en fin d'utilisation du moteur, ou lorsque l'eau est restée pendant un temps donné dans le réservoir primaire (contre le risque de croupissement), ou en cas de risque de gel de l'eau dans le réservoir primaire.

The invention also relates to a method for recovering water from the exhaust gases passing through the exhaust line of an internal combustion engine, comprising the following steps:

• mixing the exhaust gases emitted by the engine with outside air to form an enthalpy mixture, said outside air being supplied by a system for capturing and routing outside air in fluid connection with the exhaust line in downstream of the post-treatment elements (and far enough away to take advantage of the heat exchanges that take place during the path of the exhaust gases in the line), and upstream of a condensation chamber, then
• conveying and condensing said outside air/exhaust gas enthalpy mixture in a condensation chamber in order to extract the water therefrom by condensation on condensation supports, said chamber being arranged on the exhaust line downstream of a hot part of the said exhaust line, and
• recover the water thus condensed in a primary tank, located in or downstream of said condensation chamber, connected to the circuit for supplying the engine with recovered water in order to supply the recovered water to said engine (by injecting water into engine),
• emptying, in particular by pumping, depending on a given reserve of water kept in the primary tank, or in total if necessary, from said primary tank to a secondary tank located upstream of the condensation chamber, and before the connection between the outside air capture and delivery system and the exhaust line, according to programmed or detected events, in particular periodically when the engine is stopped or at the end of engine use, or when the water is remained for a given time in the primary tank (against the risk of stagnation), or in the event of a risk of the water freezing in the primary tank.

The fact that the condensation chamber is arranged on the exhaust line downstream of a hot part of said exhaust line is understood to mean that the chamber is located downstream of the gas post-treatment part, and sufficiently away to benefit from "natural" cooling of the exhaust gases.

In particular, said method comprises the following step: checking the quantity of water available in the primary tank previously at or during the starting of the engine, and if the quantity is zero or insufficient in relation to a quantity estimated to be necessary, pumping the water from the secondary tank to the primary tank.

In particular, said method comprises the step: monitoring the rate of renewal of the water in the primary reservoir, and if this rate is lower than a given rate (fixed for example by the manufacturer or a standard, and well before the conditions alteration of the water do not occur), during the next uses of the engine, for example when driving the vehicle comprising said engine, routing the water from the cold tank to the hot tank so that this water vaporizes from again and is vented to the atmosphere and/or recondensed.

In particular, said method comprises the step: managing the production of recovered water by controlling the flow rate of the outside air and/or the flow rate of the exhaust gases before the connection between the system for capturing and conveying the outside air and the exhaust line, for example by controlling controllable valves, or in the case of air by pumping the outside air with a controllable air pump, in particular an electric air pump. In particular, the outside air flow rate set point and the exhaust gas flow rate set point are determined from the desired water flow rate by applying an inverted water production model, and by applying vectors of flow rate couples of the possible exhaust gases / outdoor air flow setpoint, and by minimizing the carbon dioxide cost function

In particular in said method, the production of recovered water is managed according to a water production model by corrective learning, in particular to establish the reserve of water necessary to have in the primary reservoir.

The process for recovering water from the exhaust gases of an internal combustion engine thus described applies in particular to the operation of the motor vehicle comprising the system for recovering water from the exhaust gases described above.

• [Fig. 1] illustre schématiquement un système de récupération d'eau dans les gaz d'échappement d'un moteur à combustion interne alimentant en eau récupérée ledit moteur conformément à l'invention.
• [Fig. 2] illustre schématiquement en vue de dessous, un véhicule automobile comprenant un système de récupération d'eau dans les gaz d'échappement d'un moteur à combustion interne conformément à l'invention.
• [Fig. 3] illustre schématiquement en vue de dessous, un véhicule automobile comprenant un système de récupération d'eau dans les gaz d'échappement d'un moteur à combustion interne conformément à l'invention.
• [Fig. 4] illustre un schéma synoptique d'une stratégie de contrôle de la mise en œuvre du système de récupération d'eau du véhicule illustré en figure 2.

Other features and advantages of the invention will become apparent on reading the description given below of a particular embodiment of the invention, given by way of indication but not limiting, with reference to the appended drawings.

• [ Fig. 1 ] schematically illustrates a system for recovering water from the exhaust gases of an internal combustion engine supplying said engine with recovered water in accordance with the invention.
• [ Fig. 2 ] schematically illustrates, in bottom view, a motor vehicle comprising a system for recovering water from the exhaust gases of an internal combustion engine in accordance with the invention.
• [ Fig. 3 ] schematically illustrates, in bottom view, a motor vehicle comprising a system for recovering water from the exhaust gases of an internal combustion engine in accordance with the invention.
• [ Fig. 4 ] illustrates a block diagram of a control strategy for the implementation of the water recovery system of the vehicle shown in picture 2 .

The orientations expressed in the description of the figures are given with reference to a conventional orthonormal reference XYZ of the vehicle in which X represents the longitudinal front-rear direction of the vehicle, oriented towards the rear, Y the transverse direction of the vehicle, oriented towards the right , and Z the vertical direction oriented towards the top of the vehicle.

Identical references may be used from one figure to another to designate identical or similar elements.

The figure 1 schematically illustrates a system for recovering water from the exhaust gases of an internal combustion engine with storage of the extracted water to supply said engine with recovered water in accordance with the invention.

The figure 2 and 3 schematically illustrate a motor vehicle V, V 'in bottom view whose four wheels R1, R2, R3, R4 are represented, the water recovery system comprising variants on an outside air supply.

A powertrain comprising at least one internal combustion engine 1, which can be naturally aspirated or turbocharged (supercharged), assisted or not by electric motors. According to the example, the engine comprises four cylinders supplied with fresh air by an air intake device comprising an air inlet 100 passing through an air filter 101, a flow meter 102 to mix with the fuel, the mixture being burned in the combustion chamber 10.

At the outlet of the combustion chamber of the fuel/air mixture, a group of exhaust manifolds 2 secured respectively to the cylinder heads of the engine, collect and direct the burnt gases towards the exhaust line. According to the example, the exhaust line 20 comprises an exhaust pipe for conducting the exhaust gases to the outlet 200, the line comprising on the gas path a post-treatment system making it possible to treat the gaseous effluents as well that the particles, produced by the internal combustion engine consisting of an upstream oxygen sensor 203A then a catalytic converter 203 depolluting the effluents of certain compounds, followed by a downstream oxygen sensor 203 B, a particulate filter 204, an exhaust gas temperature sensor 205. The exhaust line also includes a silencer 201 to attenuate the noise generated by the exhaust gases.

In accordance with the invention, a system for recovering water in the exhaust gases is installed on the exhaust line downstream of the gas post-treatment and upstream of the exhaust gas outlet expelling said gases at the rear of the vehicle.

Said water recovery system comprises a device for capturing and conveying outside air, a chamber for condensing an enthalpy air/exhaust gas mixture, means for managing the extracted water comprising reservoirs extracted water storage and extracted water circulation circuits with a water pump.

According to the example, said water recovery system is located between the exhaust gas inlet (arrow G) in the silencer 201 and the exhaust gas outlet 200.

This water recovery system, according to the example illustrated in figure 1 , comprises a scoop 40 forming an air intake for capturing and conveying outside air (arrow A), captured while the vehicle is moving. It is connected to the exhaust pipe, the fluidic junction being located downstream of the gas post-treatment, according to the example at the outlet of the silencer 201, allowing a supply of fresh air (arrow A) which mixes with the exhaust gases. hot exhaust (arrow G). Advantageously, this junction will be made as far as possible from the engine outlet and after the post-treatment of the gases because the mixture must be done with gases already purified of their pollutants and far enough to benefit from a "natural" cooling of the gases. exhaust; in fact, the purified exhaust gases will have already been partially cooled by the heat exchanges between the exhaust line and the outside. In addition, the exhaust backpressure is very low at the end of the line, it is all the more easy to introduce air traveling there from the scoop (capturing air in an overpressure zone when the vehicle is moving ).

Basically, said scoop is a bent tube open at its free end to capture air while driving along a tubular part oriented along the longitudinal axis X of the vehicle, and its other open end, after the bend of the tube, is connected opening into the exhaust pipe, before the mixer.

Alternatively as illustrated by the picture 2 , the scoop 40' has a flap 43 such as a controllable valve to modulate the flow of fresh air to the condensation chamber. The scoop is a tube comprising a straight part (in the direction X) open at each end in which the air enters while driving and a tubular part connecting with the exhaust pipe in which the air circulates (arrow A1) . The flap modulates the incoming air flow (arrow A) into a first air flow (arrow A1) which is directed by the tubular joining part towards the exhaust pipe, before the mixer, to mix with the exhaust gases. exhaust, and in a flow of air (arrow A2) which emerges from the scoop at the end of the right part. The flap has the advantage of minimizing the additional drag (coefficient Cx) due to the scoop when the quantity of water to be produced is low or zero. Indeed, when the scoop flap is open, the drag of the scoop is then reduced to that of a tube, right part, whose axis is in the axis longitudinal X of the vehicle, and then being open at both ends, it generates very low drag.

According to another variant as illustrated in picture 3 , the collection of fresh air can be ensured by an air pump 44, directly taking the outside air (arrow A), and said pumped air A' is routed through a conduit cooperating with the air pump, towards the pipe of exhaust, at a point similar to the junction point as described above for the scoops, before the mixer. This pump can be controlled electrically, which has the advantage of being able to generate an enthalpy mixture even when the vehicle is not moving (with the engine running) or is at low speed. Also in the case of the air pump, the junction should be located as far away from the engine as possible. The exhaust backpressure to be overcome will thus be minimized.

In a particular arrangement as illustrated by the figure 2 or the picture 3 , said water recovery system comprises an exhaust gas by-pass, constituted according to the example of a valve 23 for controlling the flow of exhaust gases (arrow G) leaving the silencer 201. This by- pass is located downstream of the silencer, and upstream of the junction at the point of introduction of fresh air, before the mixer 4, and therefore upstream of the condensation chamber 30. This configuration is intended to facilitate the condensation of the water contained in the enthalpy mixture by taking only part of the exhaust gases (arrow G1) to adapt it to the capacities of the means to condense the water, the other part of the gases (arrow G2) being for example evacuated by a pipe 22 whose outlet 220 opens out at the rear of the vehicle. This can prove advantageous in driving conditions where the flow of fresh air would not be sufficient to bring all the exhaust gases below the dew point. The typical example here in which this bypass can be useful is that of a vehicle on a steep climb, for example the climb of a pass, the engine being very stressed, temperature and exhaust gas flow will be high with a low vehicle speed, which limits the flow of fresh air forced by the scoop ( figure 2 ).

The water recovery system comprises a condensation chamber 30 comprising condensation supports 300, constituted according to the example by fine-mesh metal grids, making it possible to promote the condensation of the water contained in the gases by the formation of droplets on the cold metal walls. These condensation supports must only generate a very low counterpressure so as not to penalize the rated operation of the motor.

The grids are arranged straight or inclined to promote the flow of water droplets.

The outside air entering (arrow A, A') in the outside air capture and delivery device 40, 40'; 40" passes through a mixer 4, located upstream of the condensation chamber 30, with the hot exhaust gases leaving the silencer 201 to homogenize said mixture and form a fresh air/hot gas enthalpy mixture leading to the condensation reaction of the water contained in vapor form in the hot exhaust gases in the condensation chamber.The water droplets thus formed in the condensation chamber flow along the condensation grids and accumulate in said chamber which forms according to this example the primary storage tank 301, also called “cold tank”, to recover in liquid form, the water vapor extracted from the exhaust gases.

In a variant not shown, the primary storage tank can be separate from the condensation chamber, it is located downstream of said chamber.

Furthermore, said water recovery system comprises a system for managing the water extracted in liquid form from said primary storage tank 301. Said management system comprises a circuit connecting said primary tank 301 and a water pump 33, and said pump being connected on the one hand to the circuit for supplying the engine with recovered water 32, and on the other hand to a circuit for returning recovered water 34, also called the end-of-mission circuit, to a secondary storage tank 302 located upstream of the condensation chamber. This secondary tank, called “hot tank”, is constituted according to the example by the silencer, more precisely by the envelope of the silencer.
As illustrated in figure 1 , the circuit for supplying the engine with recovered water 32 ends with an injection rail 35 equipped with injectors 350 in order to inject the water into the air intake circuit at the level of the engine (one injector per cylinder).

As a variant, the injection of water into the engine can take place directly into the combustion chamber.

The secondary storage tank 302 is a tank into which up to all of the water contained in the primary tank can be discharged. In fact, its capacity must be greater than that of the primary reservoir, especially since the water can freeze there. It must be insensitive to the solidification of water, in other words it must not be sensitive to frozen water, it must not crack, tear or even deform on the passage of water from the state liquid to solid. In driving conditions of the vehicle, there must be sufficiently high temperatures to allow the liquefaction and evaporation of the water. Thus, this hot tank makes it possible to drain the water accumulated in the cold tank at the end of driving so as to avoid the problem of managing frost in the cold tank. This emptying of the cold tank, at the end of the mission, makes it possible to make the system operational quickly with the water produced at the start of the mission (no need to wait for the water produced during the previous runs to thaw).

The emptying of the primary tank at the end of the mission must not take place in the immediate vicinity of the vehicle, so as not to risk forming a plate of frost on the roadway. This is why the volume of water stored in the primary tank will be returned upstream of the condensation chamber 30, in the "hot tank", the silencer according to the example, where the water thus discharged can freeze without risk. .

In addition, this transfer of water from the primary tank to the hot secondary tank prevents the water extracted from stagnating, because the water will then be vaporized due to the temperatures prevailing there when the engine is running, and will pass into the exhaust gases. hot exhaust to be condensed and/or expelled.

The water pump 33 makes it possible to supply recovered water to the engine supply circuit by the water thus produced, from the primary tank to its place of introduction into the engine, and also to drain this water accumulated at the end of taxiing, possibly during taxiing, from the primary tank to the secondary tank.

In addition, this pump is preferably self-priming to be able to act in discharge/pumping in order to also be able to drain the supply circuit of the engine to prevent freezing if necessary, and to allow the transit of water in both directions between the secondary tank and the primary tank.

The figure 4 represents a block diagram of a strategy for implementing and controlling a configuration similar to that according to the configuration according to the picture 2 .

In the initial phase (line 50) relating to the events preceding the start of the engine or shortly after the latter, a control of the volume of water required is present in the primary tank (block 501), if not the system verifies whether the water is recoverable in the secondary reservoir (block 502). If yes, the system in the taxiing phase (line 51) checks the status of the system's pump 33 (blocks 512, 513, 516), and if correct, the production supervisor requests the quantity of water required for maintaining water reserve for the primary reservoir (block 518) and the water production model is activated (block 520), and when the required water level is reached (block 522) the injection of water in the engine is possible (block 524). If the required water level is not reached, the system is temporarily unavailable (block 515), and engine performance is limited (block 519).
Similarly, when the volume of recoverable water in the secondary tank (block 502) is not available at the start, if the reserve of water is built up sufficiently while driving (block 511), the system rejoins the control cycle normal (block 512), otherwise it goes to waiting for conformity to the prediction of the water production model (block 513), and if it is positive it returns to block 511, whereas if it is negative a diagnosis of fault is enabled (block 517) and engine performance is limited until repaired (block 521).
At the end of driving or while the vehicle is stopped (line 53), the system checks whether a risk of freezing is detected or whether the water has been stored for longer than required in the primary tank (block 530), and whether yes, the system orders the emptying of the primary tank towards the secondary and the emptying of the pump and the circuit pipes (block 531), if not the computer is authorized to be switched off (block 532).

• de maximiser la production d'eau selon les conditions externes subies (Température des gaz échappement, débit des gaz d'échappement, hygrométrie, vitesse véhicule, température d'air frais),
• de minimiser l'impact du système sur la traînée (Cx) lorsque la récupération d'eau dans l'échappement n'est plus souhaitable (réserve d'eau pleine). En effet la présence d'une écope supplémentaire dans le flux d'air d'écoulement autour du véhicule peut pénaliser la traînée aérodynamique du véhicule,
• de minimiser la consommation électrique du véhicule si l'acheminement d'air est assuré par une pompe électrique ,
• de minimiser la perte de rendement liée à l'augmentation de la contre-pression échappement lorsque la production d'eau n'est pas nécessaire,
• de refroidir la chambre de condensation ainsi que ses éléments constitutifs en ouvrant l'écope et en déviant les gaz d'échappement pour qu'ils ne passent pas dans la chambre de condensation, ceci permettant ponctuellement de refroidir la chambre de condensation afin de favoriser la condensation ultérieurement.

A strategy for adapting the system by controlling the action levers (actuators) is established, depending on the use case, with the aim of:

• to maximize water production according to the external conditions experienced (Exhaust gas temperature, exhaust gas flow, humidity, vehicle speed, fresh air temperature),
• to minimize the impact of the system on the drag (Cx) when the recovery of water in the exhaust is no longer desirable (full water reserve). Indeed the presence of an additional scoop in the flow of air flow around the vehicle can penalize the aerodynamic drag of the vehicle,
• to minimize the electric consumption of the vehicle if the routing of air is ensured by an electric pump,
• to minimize the loss of efficiency linked to the increase in the exhaust back pressure when the production of water is not necessary,
• to cool the condensation chamber as well as its constituent elements by opening the scoop and deflecting the exhaust gases so that they do not pass into the condensation chamber, this allowing the condensation chamber to be cooled occasionally in order to promote the condensation later.

In a particular configuration, a direct measurement of the relative wind; by anemometer, Pitot probe, or indirectly by analysis of the drag force at constant speed, etc., makes it possible to refine the opening setpoint to obtain a target fresh air flow.

In a particular configuration, the direct measurement of the air flow makes it possible to slave the opening of the scoop valve to a target flow of fresh air. This flow measurement can be made by means of a physical flow meter or by a correlation of the flow to the counterpressure measured at the terminals of the pilot valve for example.

A water reserve supervisor issues the water production needs, in mg/s for example, this request is established taking into account the quantity consumed, the stock and possibly a forecast quantity based on the information of the trip, the driver habits etc.

The quantity of water to be extracted is deduced in particular from the following information, temperature and flow rate of the exhaust gases to be mixed (or set point if controlled via a valve), fuel richness, fuel formulation, temperature and air flow outside (or setpoint if controlled via a lifting scoop), hygrometry.

• la formulation du carburant utilisé (Rapport C/H/O),
• la fonction de transfert entre la surface efficace de l'écope et la production d'eau
• la fonction de transfert entre l'ouverture de la vanne des gaz d'échappement et la production d'eau,
• le recalage de la fonction de transfert Hygrométrie de l'air / quantité d'eau produite.

The level of water actually produced can be measured directly by an electronic gauge, or by periodic forced emptying with measurement of the quantity injected by the injectors. Knowledge of the possible difference between the prediction of water produced and the water actually produced makes it possible to learn and readjust the real state of the system by:

• the formulation of the fuel used (C/H/O ratio),
• the transfer function between the effective bailer area and the water production
• the transfer function between the opening of the exhaust gas valve and the production of water,
• the readjustment of the Air humidity / quantity of water produced transfer function.

These readjustments make it possible to make the system robust to the dispersion of water production, changes of environment, change of fuel, etc.

• recaler le paramètre lié à la formulation carburant juste après un remplissage du réservoir d'essence,
• recaler les autres paramètres lorsque l'hygrométrie est à 0 (dans le cas de températures extérieures très froides par exemple),
• fermer le bypass des gaz échappement pour recaler la fonction de transfert Débit de gaz frais = f(Ouverture de vanne écope ; vent relatif).

In order to make the adjustment more precise, it can modify the impact of a particular parameter following a specific event:

• readjust the parameter linked to the fuel formulation just after filling the petrol tank,
• readjust the other parameters when the hygrometry is at 0 (in the case of very cold outside temperatures for example),
• close the exhaust gas bypass to reset the transfer function Fresh gas flow = f (Scoop valve opening; relative wind).

If the difference between water production and the actual state of the system is beyond a threshold, an operating fault can be suspected.

Under normal conditions, the water reserve supervisor operates as explained below.

At the start of the mission, the engine is cold, the "cold" tank is empty. Water forms quickly as soon as the engine is started, condensing on contact with the exhaust line, which is cold at this moment
The water thus accumulated forms a first reserve volume. This is estimated according to the start-up conditions and according to time (external temperature, engine coolant temperature ("coolant"), temperature in the exhaust, Exhaust gas temperature, Exhaust gas mass flow (Qech)), Richness in the diesel engine (for the gasoline engine it is constant, oscillating slightly around 1).

• si la demande d'injection d'eau est nulle, et que le réservoir d'eau injectable a atteint son niveau de consigne, l'écope est fermée ou masquée par une pièce constitutive du véhicule (silencieux, traverse, ou toute autre pièce pouvant faire office de masque ...) afin de ne pas pénaliser le coefficient de traînée du véhicule couramment appelé Cx. Si le by-pass des gaz d'échappement est présent, il sera mis dans sa configuration qui minimise la contre pression échappement.
• si la demande de production d'eau est nécessaire, le superviseur émet la quantité d'eau à produire, les leviers pour atteindre cette consigne sont alors, et/ou :
  • de faire varier la surface efficace de l'écope (celle-ci étant à moduler en fonction de la vitesse du véhicule, de l'hygrométrie de l'air et de la température extérieure),
  • de prélever une partie plus ou moins importante des gaz d'échappement (à moduler en fonction du débit massique des gaz, de leur température),
    Ces leviers sont actionnés par le modèle de production d'eau. Comme évoqué ci-dessus, pour affiner la prédiction du modèle, un bouclage permet de confronter la prévision de production à la production réelle. Le modèle de production est donc recalé par itération corrective. Cette adaptation permet de recaler les paramètres décrits ci-dessus.

After this initial phase, comes the management phase, where the water is produced according to demand in order to keep a stock of water defined so as to avoid a break in the water supply to the engine while driving:

• if the water injection request is zero, and the water injection tank has reached its set level, the scoop is closed or concealed by a constituent part of the vehicle (silencer, crossmember, or any other part that may act as a mask ...) in order not to penalize the drag coefficient of the vehicle commonly called Cx. If the exhaust gas bypass is present, it will be set to its configuration which minimizes the exhaust back pressure.
• if the water production request is necessary, the supervisor issues the quantity of water to be produced, the levers for reaching this instruction are then, and/or:
  • to vary the effective surface of the scoop (this being to be modulated according to the speed of the vehicle, the hygrometry of the air and the outside temperature),
  • to take a more or less significant part of the exhaust gases (to be modulated according to the mass flow of the gases, their temperature),
    These levers are operated by the water production model. As mentioned above, to refine the model's prediction, a loop makes it possible to compare the production forecast with the actual production. The production model is therefore readjusted by corrective iteration. This adaptation makes it possible to readjust the parameters described above.

The water reserve supervisor aims to maintain a buffer water level to deal with the unexpected. This is the level of reserve to be reached, deemed optimal.
Once this prior stock of water has been constituted, the supervisor aims to maintain this level by issuing to the water production model a setpoint making it possible to exactly compensate for the water consumption of the engine. However, the supervisor can also take into account a usage forecasting aspect coupled with knowledge of the driving profile (geographical data by GPS) and of the customer usage profile. This is to respond to case of difficult uses such as the production of water at low speed of a vehicle under heavy load (for example in the case of a mountain pass), or to temporarily minimize production if conditions are more favorable for production of water are imminent (for example in the case of the descent of the pass). This forecast therefore makes it possible to secure the water supply and produce water at a lower environmental cost, in particular in terms of carbon dioxide (CO2) if future driving conditions allow it.

In the case of a configuration having two lever arms (external air, exhaust gas), it is possible to choose the best exhaust gas flow set point/fresh air set point pair allowing the desired quantity of water to be produced by using a function to minimize the CO2 cost.

• lors des prochains roulages, l'eau du réservoir froid sera acheminée vers le réservoir chaud de manière à ce qu'elle se vaporise de nouveau et qu'elle soit évacuée à l'atmosphère ou recondensée. Cette action a donc pour effet de forcer le taux de renouvellement de l'eau, de manière transparente pour l'usager.

Once the rolling is done, the water maintained in liquid form is kept in the cold tank. This is so that the system is ready if the driver returns to his vehicle shortly afterwards.
After a sufficiently long time, or if the risk of frost is felt, the cold tank is drained into the hot tank.
In a particular embodiment, if the conditions allow it (hot outside temperatures (Text >> 0°C) for example or no risk of frost), it will be possible to re-aspirate the water stored in the hot tank to put it back in the cold reservoir used for the injection circuit.
A water quality monitoring strategy makes it possible to prevent cases in which a user very rarely encounters the conditions that require the injection of water into the engine. Indeed, if the water consumption is very low, the latter could never be renewed with the risk of deteriorating, of becoming acidified, or of becoming loaded with metal particles, soot or other carbonaceous materials, which could adversely affect the engine or the water injection system.
In order to prevent this from happening, monitoring of the renewal rate is in place.
If this rate is judged to be too low, and well before the weathering conditions arise, the following action is taken:

• during the next rides, the water from the cold tank will be routed to the hot tank so that it vaporizes again and is vented to atmosphere or recondensed. This action therefore has the effect of forcing the water renewal rate, transparently for the user.

This dynamic management of the quality of the water, possible thanks to the device for emptying the cold tank, is one of the great advantages of this invention; whereas in the case of external water recharge, water purification systems must be provided.

This invention has the advantage of being autonomous (without human intervention) and of having the best availability of the function of injecting water into the engine by eliminating, for example, the risk of non-availability of the system in the event of non refilling the water tank.

Compared to previous solutions with heat exchanger, the system according to the invention has the advantage of being economical (no cost of an exchanger, with significant cooling requirements) and of being easy to implement, in particular because it does not require additional cooling on the front of the vehicle.

The responsiveness of the system according to the invention and its ability to regulate the quantity of water produced makes it possible to facilitate the storage of water. The water production and management management strategy makes it possible to recover only the strictly necessary volume of water in the exhaust line. It thus limits the drag induced by the scoop, or the exhaust counter-pressure necessary to take off the adequate flow.

Water management and in particular the draining system upstream of the condensation chamber at the end of driving protects against non-operation in the case of use of starting in very cold conditions (Text << 0°C) .

Claims (10)

Motor vehicle (V, V') comprising a powertrain comprising at least one internal combustion engine (1), an exhaust line (20) with a part comprising post-treatment means (203, 204, 201) of exhaust gases produced by the engine, a system for recovering water in the exhaust gases including a circuit for supplying the engine with recovered water (32, 35, 350), characterized in that said recovery system water in exhaust gas includes: - a condensation chamber (30) for an enthalpy outside air/exhaust gas mixture to extract the water therefrom, arranged in the exhaust line downstream of the exhaust gas post-treatment part, - an outside air capture and delivery system (40, 40', 40", 43, 44), having a fluidic connection with the exhaust line downstream of the exhaust gas post-treatment part exhaust and upstream of said condensation chamber, and - at least two separate tanks (301, 302) for storing the recovered water, one constituting a primary tank (301) located in or downstream of said condensation chamber and which supplies the water which will supply the motor , and the other constituting a secondary reservoir (302) located upstream of the condensation chamber, and - Circulation means (33) of the recovered water allowing at least one circulation of water from said primary tank to said secondary tank and from said primary tank to the motor supply circuit with recovered water. Motor vehicle according to Claim 1, characterized in that the said secondary tank (302) has a capacity greater than that of the primary tank (301). Motor vehicle according to one of Claims 1 to 2, characterized in that it comprises means (33) for circulating the recovered water allowing at least circulation of the recovered water at double direction between said primary tank (301) and said secondary tank (302), and preferably it also comprises means for circulating the recovered water in both directions between said primary tank (301) and the motor supply circuit in reclaimed water (32, 35, 350). Motor vehicle according to one of Claims 1 to 3, characterized in that the said system for capturing and conveying outside air comprises means (43, 44) for controlling the flow rate of the flow of outside air mixing with the gases exhaust. Motor vehicle according to one of Claims 1 to 4, characterized in that the said water recovery system comprises means (23) for controlling the flow rate of the flow of exhaust gases mixing with the outside air to form the enthalpy mixture. Motor vehicle according to one of Claims 1 to 5, characterized in that it comprises a supervisor of a minimum quantity of water constituting a reserve of water in the primary reservoir, in conjunction with a water production model , in particular as a function of parameters relating to the meteorological conditions, and/or to the characteristics of the fuel and/or of the intake air and/or of the exhaust gases and/or of the outside air forming the enthalpy mixture, and/or the road profile that the vehicle travels. Process for recovering water from the exhaust gases passing through the exhaust line (20) of an internal combustion engine (1), including supplying the engine with recovered water, characterized in that it comprises the following steps: - mixing the exhaust gases emitted by the engine with outside air to form an enthalpy mixture, said outside air being supplied by an outside air capture and delivery system (40, 40', 40", 43, 44) in fluid connection with the exhaust line downstream of the post-treatment elements (203, 204, 201), and upstream of a condensation chamber (30), then - conveying and condensing said outside air/exhaust gas enthalpy mixture in said condensation chamber (30) to extract the water therefrom by condensation on condensation supports (300), said chamber being arranged on the exhaust line downstream of the hot part of said exhaust line, and - recovering the water thus condensed in a primary tank (301), located in or downstream of said condensation chamber, connected to the circuit for supplying the motor with recovered water (32, 35, 350) in order to supply water recovered said engine, - emptying, in particular by pumping, according to a given reserve of water kept in the primary reservoir (301), or entirely if necessary, from said primary reservoir (301) towards a secondary reservoir (302) located upstream of said condensation chamber, and before the connection between the system for capturing and conveying outside air and the exhaust line, according to programmed or detected events, in particular periodically during engine stops or at the end of use of the engine, or when the water has remained for a given time in the primary tank, or when there is a risk of the water freezing in the primary tank. Method according to claim 7, characterized in that it comprises the step: checking the quantity of water available in the primary tank previously at or during the starting of the engine, and if the quantity is zero or insufficient with respect to a quantity estimated necessary, pumping the water from the secondary tank (302) to the primary tank (301). Method according to one of Claims 7 to 8, characterized in that it comprises the step: monitoring the rate of renewal of the water in the primary reservoir (301), and if this rate is lower than a given rate, the next time the engine is used, route the water from the cold tank to the hot tank so that this water vaporizes again and is evacuated to the atmosphere and/or recondensed. Method according to one of Claims 7 to 9, characterized in that it comprises the step: managing the production of recovered water by controlling the flow rate of the outside air and/or the flow rate of the exhaust gases before the connection between the outside air capture and delivery system and the exhaust line. ] ]

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