Reducing fluid sprayer

Abstract

Reducing Fluid Sprayer The invention relates to a reducing fluid (R) sprayer (1) for a mixer (2), suitable for mixing the reducing fluid (R) with exhaust gases circulating in the mixer (2), comprising a heating chamber (3), an inlet valve (4) suitable for controlling the quantity of reducing fluid (R) entering the heating chamber (3), an outlet valve (5) suitable for controlling the quantity of reducing fluid (R) exiting the heating chamber (3) and being sprayed into the mixer (2), a thermal means (6) suitable for controlling the temperature of the heating chamber (3), and a controller (7) suitable for determining control parameters (ΔTe, ΔTs, θ) as a function of the desired parameters of the sprayed reducing fluid jet (α, V, δ). Figure for the abstract: 1

Description

Title of the invention: Reducing fluid sprayer technical field

[0001] The invention relates to a reducing fluid sprayer, such as AUS32, for a mixer, suitable for mixing the reducing fluid with exhaust gases circulating in the mixer. Previous technique

[0002] Such a sprayer is designed to spray reducing fluid into a mixer. It comprises a nozzle for spraying the reducing fluid into a mixing chamber of the mixer. The mixer is integrated into an exhaust line. Exhaust gases from an internal combustion engine flow through the mixer into the mixing chamber, where they are mixed with the sprayed reducing fluid.

[0003] The reducing fluid comprises ammonia in gaseous form or any precursor of ammonia in gaseous or liquid form, such as urea. The urea is preferably in the form of an aqueous urea solution, such as FAUS32, also known as DEF or commercially as AdBlue®.

[0004] The characteristics of a sprayer are most often determined by the design parameters of the sprayer and / or mixer. These parameters are the characteristics of the spray nozzle, the spray pressure, the spray time or the quantity of reducing fluid sprayed, and the temperature of the reducing fluid. These parameters, which are generally fixed, determine fixed characteristics of the spray jet.

[0005] This is detrimental because the exhaust gas flow is variable. A fixed spray jet is advantageously suited to an average exhaust gas flow. At low engine speeds, a smaller exhaust gas flow is present. A fixed spray jet is likely to be too strong and may pass through the exhaust gas flow, reach an opposite wall of the mixer, and, detrimentally, deposit there, thus avoiding mixing with the exhaust gas flow. At high engine speeds, a larger exhaust gas flow is present. A fixed spray jet is likely to be too weak and may not penetrate the exhaust gas flow sufficiently and may not mix with it properly. In both cases, low and high engine speeds, a loss of mixer efficiency is observed. Summary of the invention

[0006] The object of the invention is to be able to modify the characteristics of the spray jet, typically in order to be able to adapt them to the operating conditions of the engine and especially its engine speed, which determines the characteristics of the exhaust gas flow.

[0007] For this purpose, the invention relates to a reducing fluid sprayer, for a mixer, suitable for mixing the reducing fluid with exhaust gases circulating in the mixer, comprising a heating chamber, an inlet valve suitable for controlling a quantity of reducing fluid entering the heating chamber, an outlet valve suitable for controlling a quantity of reducing fluid exiting the heating chamber and spraying into the mixer, a thermal means suitable for controlling a temperature of the heating chamber and a controller suitable for determining control parameters as a function of the desired parameters of the sprayed reducing fluid jet.

[0008] Specific features or embodiments, usable alone or in combination, are:

[0009] - the control parameters are an inlet valve opening time, a duration of outlet valve opening and a setpoint temperature of the thermal device,

[0010] - the parameters of the sprayed reducing fluid jet are: an opening angle, a spraying speed and vapor rate,

[0011] - the controller determines the control parameters according to the jet parameters of desired sprayed reducing fluid, using a predetermined lookup table,

[0012] - the lookup table is predetermined by calibration on the test bench and / or in simulation,

[0013] - the desired parameters of the sprayed reducing fluid jet are determined in function of exhaust gas flow rate and temperature.

[0014] According to a second aspect of the invention, a reducing fluid mixer comprising such a sprayer.

[0015] According to a third aspect of the invention, an exhaust line comprising such a mixer. Brief description of the drawings

[0016] The invention will be better understood upon reading the following description, given solely by way of example, and with reference to the figures in the appendix in which:

[0017] [Fig-1] shows, in schematic view, a sprayer, during the 4 phases of a spray cycle,

[0018] [Fig.2] shows a time diagram illustrating the cycle,

[0019] [Fig.3] shows a diagram recalling the characteristics of the jet. Description of the implementation methods

[0020] With reference to Fig. 1, illustrating a sprayer 1 according to the invention, in four successive and recurring states E1-E4 of a spraying cycle, the invention relates to a sprayer 1 of reducing fluid R, such as AUS32, for a mixer 2, capable of mixing the reducing fluid R with exhaust gases circulating in the mixer 2.

[0021] Such a sprayer 1 is designed to spray reducing fluid R into a mixer 2. It comprises a nozzle adapted to spray the reducing fluid R into a mixing chamber of the mixer 2. The mixer 2 is integrated into an exhaust line. Exhaust gases from an internal combustion engine flow through the mixer 2 into the mixing chamber, where they are mixed with the sprayed reducing fluid R.

[0022] The reducing fluid R comprises ammonia in gaseous form or any precursor of ammonia in gaseous or liquid form, such as urea. The urea is preferably in the form of an aqueous urea solution, such as AUS32, also known as DEF or commercially as AdBlue.

[0023] In order to transform the reducing fluid R into ammonia, which is more easily mixed with the exhaust gases during spraying, the reducing fluid R is advantageously heated upstream of its spraying, in order to obtain immediate vaporization during spraying.

[0024] For this purpose, the sprayer 1 is equipped, in a known manner, with a heating chamber 3. Positioned upstream of the nozzle, the heating chamber 3 allows the vapor rate θ and the temperature θ of the reducing fluid R to be varied.

[0025] The sprayer 1 further includes, at the inlet of the heating chamber 3, an inlet valve 4 allowing control of the quantity of reducing fluid R entering the heating chamber 3. The supply line for reducing fluid R to the heating chamber 3 is under positive pressure relative to the heating chamber 3. Therefore, an inlet of reducing fluid R occurs as soon as the inlet valve 4 is opened.

[0026] The sprayer 1 further includes, at the outlet of the heating chamber 3, an outlet valve 5 for controlling the quantity of reducing fluid R exiting the heating chamber 3 and being sprayed into the mixer 2. The heating chamber 3 is under positive pressure relative to the mixer 2. Therefore, an outlet of reducing fluid R and its spraying occur as soon as the outlet valve 5 is opened. The sprayer 1 further includes a thermal means 6 for controlling the temperature of the heating chamber 3 and thus the temperature θ of the reducing fluid R contained in the heating chamber 3.

[0027] As illustrated in [Fig. 2], the spray cycle takes place in four phases. During a first phase T1, only the inlet valve 4 is open in order to fill, at least partially, the heating chamber 3 with reducing fluid R. This corresponds to state El in [Fig. 1]. The duration of phase T1 is the opening time ATe of the inlet valve 4. At the end of phase T2, the inlet valve 4 is closed. This corresponds to state E2 of [Fig. 1]. During phase T3, the heating chamber 3 is heated until it reaches the setpoint temperature 0. This corresponds to state E3 of [Fig. 1]. During phase T3, only the outlet valve 5 is open in order to empty, at least partially, the mixing chamber 2 by spraying the reducing fluid R. The duration of phase T3 is the opening time ATs of the outlet valve 5. This corresponds to state E4 of [Fig. 1]. Phase T4 corresponds to a waiting period before restarting a new spraying cycle, via an initial phase TL

[0028] According to one feature, the sprayer 1 further includes a controller 7. This controller 7 controls the inlet valve 4, the outlet valve 5 and the thermal means 6. The controller 7 is capable of determining control parameters of the inlet valve 4, the outlet valve 5 and the thermal means 6, in order to obtain the desired parameters of the sprayed reducing fluid jet.

[0029] According to another feature, the control parameter of the inlet valve 4 is, for example, a duration ATe for the opening of the inlet valve 4. This duration ATe allows the incoming volume of reducing fluid R to be varied. The control parameter of the outlet valve 5 is, for example, a duration ATs for the opening of the outlet valve 5. This duration ATs allows the outgoing volume of reducing fluid R to be varied, and therefore the volume of reducing fluid R sprayed into the mixing chamber 2. The control parameter of the thermal means 6 is, for example, a setpoint temperature 0 that the reducing fluid R must reach.

[0030] It is obvious to a person skilled in the art that the invention could operate with other control parameters. Thus, the quantity of reducing fluid R could be controlled by one or more volumes or masses. The temperature could be controlled by a quantity of heat, a heating time, a pressure, etc.

[0031] According to another feature, the parameters of the sprayed reducing fluid jet are, for example, the opening angle of the spray cone a, the velocity V of the sprayed jet and the vapor rate ô of the sprayed reducing fluid.

[0032] This is recalled in [Fig.3], showing a downward spray jet, with a its opening angle, V its velocity or the equivalent magnitude its depth of projection, and ô its vapor ratio or density.

[0033] It is obvious to a person skilled in the art that the invention could work with other parameters of the sprayed reducing fluid jet.

[0034] According to another feature, the controller 7 determines the control parameters ATe, ATs, 0, as a function of the desired parameters of the sprayed reducing fluid jet a, V, ô. For this purpose, the controller 7 uses a predetermined lookup table ir. The lookup table ir indicates, for a triplet (a, V, ô) of parameters of the desired sprayed reducing fluid jet, a triplet (ATe, ATs, 0) of control parameters to be applied, (ATe, ATs, 0) = ir (a, V, ô).

[0035] According to another feature, the corresponding ir table is predetermined by calibration on the test bench and / or by simulation. On the test bench, the control parameters are varied, and the jet parameters are observed. The jet parameters are observed, for example, using a high-speed camera or a paternator. The vapor rate θ is indirectly obtained by integrating the mass of injected liquid droplet measured by laser extinction and diffraction.

[0036] The reducing fluid R in the heating chamber 3 is in a two-phase state. It combines liquid and vapor. This depends on the filling time ATe of the inlet valve T4 and the pressure in the heating chamber 3 itself, which is temperature-dependent according to the saturation characteristic. Thus, for example, if the temperature 0 in the heating chamber 3 is regulated at 160°C, the pressure is 7 bar, which corresponds to the saturation temperature.

[0037] As an example, the spray angle α is adjusted using the opening time ATs of the outlet valve 5. The spray velocity V is adjusted using the temperature θ. The quantity of reducing fluid sprayed is adjusted by the opening time ATe of the inlet valve 4. The vapor ratio θ is adjusted by the opening time ATs of the outlet valve 5 and by the temperature θ. There are interactions between the control parameters, and joint adjustment may be necessary. All these relationships are determined on the test bench and / or by simulation of the spraying process. All of this is stored in the lookup table ir.

[0038] The sprayer 1, thus modified according to the invention, is advantageously suited to adapting the parameters a, V, θ of the sprayed reducing fluid jet. The desired parameters of the sprayed reducing fluid jet a, V, θ are then advantageously determined as a function of the exhaust gas flow characteristics, such as its flow rate and temperature. The exhaust gas characteristics are measured, observed, or determined as a function of the engine's operating parameters and history, such as engine speed.

[0039] The invention further relates to a reducing fluid mixer 2 R, comprising such a sprayer 1.

[0040] The invention further relates to an exhaust line, comprising such a mixer 2.

[0041] The invention has been illustrated and described in detail in the drawings and the preceding description. This description is to be considered illustrative and given by way of example and not as limiting the invention to this single description. Numerous embodiments are possible. List of reference signs

[0042] 1: sprayer,

[0043] 2: mixer,

[0044] 3: heating chamber,

[0045] 4: inlet valve,

[0046] 5: outlet valve,

[0047] 6: thermal means,

[0048] 7: controller,

[0049] a: angle of the jet,

[0050] ô: vapor rate,

[0051] ATe: inlet valve opening time,

[0052] ATs: outlet valve opening time,

[0053] R: reducing fluid,

[0054] 0: temperature,

[0055] V: jet velocity,

[0056] jt: lookup table.

Claims

Demands

1. A reducing fluid (R) sprayer (1) for a mixer (2), suitable for mixing the reducing fluid (R) with exhaust gases circulating in the mixer (2), comprising a heating chamber (3), an inlet valve (4) suitable for controlling the quantity of reducing fluid (R) entering the heating chamber (3), an outlet valve (5) suitable for controlling the quantity of reducing fluid (R) exiting the heating chamber (3) and being sprayed into the mixer (2), and a thermal means (6) suitable for controlling the temperature of the heating chamber (3), further characterized in that it comprises a controller (7) suitable for determining control parameters (ATe, ATs, 0) as a function of the desired parameters of the sprayed reducing fluid jet (a, V, θ), the parameters of the sprayed reducing fluid jet (a, V, θ) being an opening angle (a) and a spray velocity. (V) and a vapor rate (δ).

2. Sprayer (1) according to the preceding claim, wherein the control parameters (ATe, ATs, 0) are an opening time (ATe) of the inlet valve (4), an opening time (ATs) of the outlet valve (5) and a setpoint temperature (0) of the thermal means (6).

3. Sprayer (1) according to any one of the preceding claims, wherein the controller (7) determines the control parameters (ATe, ATs, 0), as a function of the desired parameters of the sprayed reducing fluid jet (a, V, ô), by means of a predetermined lookup table (ji).

4. Sprayer (1) according to the preceding claim, wherein the correspondence table (jt) is predetermined by calibration on the test bench and / or in simulation.

5. Sprayer (1) according to any one of the preceding claims, wherein the desired parameters of the sprayed reducing fluid jet (a, V, ô) are determined as a function of an exhaust gas flow rate and temperature.

6. Reducing fluid mixer, characterized in that it comprises a sprayer (1) according to any one of the preceding claims.

7. Exhaust line, characterized in that it comprises a mixer according to the preceding claim.

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