System and method for bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with an internal combustion engine

Abstract

The invention relates to a method for the bio-decontamination of an aqueous solution held in a tank on board a motor vehicle having a combustion engine. According to the invention, this method comprises the following steps: • Obtaining information encoded in a navigation system or GPS system, said information comprising at least a first journey time, tr1; • If the first journey time, tr1, is greater than a first time value, t1, triggering the heating of the aqueous solution held in the holding tank in order to reach a first temperature of the aqueous solution, T1, at least equal to 60°C for a second time value, t2, • Keeping the aqueous solution at at least said first temperature of the aqueous solution, T1, for a third time value, t3.

Description

[0001] The invention relates to the field of internal combustion engine vehicles such as cars. More particularly, the invention relates to a method for the bio-decontamination of an aqueous solution contained in a tank on board an internal combustion engine vehicle, more particularly a turbocharged direct injection gasoline engine, and a system for the bio-decontamination of an aqueous solution contained in a tank on board an internal combustion engine vehicle, more particularly a turbocharged direct injection gasoline engine, capable of implementing said method.

[0002] The invention is intended for use, in particular, in the field of water injection into the air intake circuit of an internal combustion engine. In the case of water injection, this water mixes with the intake gas and makes it possible to reduce combustion temperatures and emissions of pollutants called NOx, but also to increase performance, for example, of a gasoline engine by reducing susceptibility to knocking.

[0003] A known problem with water injection systems is that the water can contain impurities which, in turn, promote the growth of bacteria, algae, fungi, or other microorganisms. This can lead to system malfunctions, even failures, as well as clogging of the filters within the water injection system. To prevent such contamination or to eradicate existing contamination, one might consider using chemicals. However, injecting such chemicals into the combustion chamber can cause other problems.

[0004] It is therefore essential to have a very lightly loaded aqueous solution, preferably free of bacteria, algae, fungi or other microorganisms, within the reservoir.

[0005] Documents EP 3018331 A1 and DE 10 2016 011488 A1 disclose the possibility of decontaminating an aqueous solution by heating it. However, such heat treatment does not guarantee sufficient decontamination of the aqueous solution.

[0006] Another solution is known from document DE 10 2016 011488 A1.

[0007] The invention aims in particular to overcome these drawbacks of the prior art.

[0008] More specifically, an objective of the invention, in at least one of its embodiments, is to implement a bio-decontamination process for an aqueous solution contained in a tank on board a motor vehicle with an internal combustion engine as defined in claim 1, said process being required to allow sufficient bio-decontamination.

[0009] Another objective of the invention, in at least one of its embodiments, is to provide a bio-decontamination system for an aqueous solution contained in a tank on board a motor vehicle with an internal combustion engine capable of implementing said process.

[0010] According to a particular embodiment, the invention relates to a process for the bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with an internal combustion engine.

[0011] According to the invention, such a process comprises the following steps: Encoding of the destination location in a navigation system or GPS system, Obtaining the information calculated by the navigation system or GPS system, said information including at least a first travel time, t r1; If the first travel time, t r1, is greater than a first time value, t 1, activating a heating of the aqueous solution contained in the tank in order to reach a first temperature of the aqueous solution, T 1, at least equal to 60°C during a second time value, t 2, Maintaining the aqueous solution at least said first temperature, T 1, for a third time value, t 3, greater than 20 minutes, preferably greater than 75 minutes, and even more preferably greater than 105 minutes.

[0012] The general principle of the invention is based on the use of the initial travel time, tr1, calculated by the navigation or GPS system. This initial travel time, tr1, determines whether or not the aqueous solution in the tank is heated to perform bio-decontamination by heating. Since bio-decontamination by heating is relatively long, on the order of at least an hour depending on the quantity of aqueous solution in the tank and the type of microorganisms to be eliminated, sufficient travel time is necessary to perform the bio-decontamination by heating the aqueous solution. Furthermore, bio-decontamination by heating the aqueous solution for too short a time could even have the opposite effect and increase bacterial proliferation if the cycle is stopped when the water is at approximately 37°C.Thus, a bio-decontamination cycle is only initiated when the estimated travel time provided by the navigation or GPS system exceeds the time required to kill microorganisms with a lethal temperature in solution of at least 60°C. This duration can also be adjusted based on the initial temperature of the aqueous solution in the tank or on the volume of aqueous solution in the tank, this volume being measured, for example, using a level sensor.

[0013] The term "bio-decontamination" refers to the destruction of at least 90% of the microorganisms present in the aqueous solution, said microorganisms having a lethal temperature of at least 60°C.

[0014] The term "lethal temperature of a microorganism" refers to the temperature at which the aqueous solution must be maintained for a certain period of time to kill the microorganism. This period of time is preferably less than four hours, more preferably less than three hours, and most preferably less than two hours.

[0015] Advantageously, the process of bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with an internal combustion engine is such that it includes a step of measuring the level of the aqueous solution in the tank; if the level of the aqueous solution measured is less than the maximum level of aqueous solution that can be contained in the tank, then the heating time of the aqueous solution contained in the tank, corresponding to the sum of the second time value, t2, and the third time value, t3, is calculated on the basis of the actual volume of aqueous solution, said actual volume of aqueous solution being calculated on the basis of the level value of the aqueous solution measured.

[0016] The expression "actual volume of aqueous solution" refers to the volume of aqueous solution present in the reservoir.

[0017] Thus, such a step of measuring the level of the aqueous solution in the tank makes it possible to optimize the bio-decontamination time, in other words the duration of the heating step of the aqueous solution in the bio-decontamination process by heating, depending on the quantity of aqueous solution to be treated.

[0018] According to an advantageous implementation, the process of bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with an internal combustion engine is such that it includes a step of measuring a second temperature of the aqueous solution, T2, if the second temperature of the aqueous solution, T2, measured is greater than a third temperature, T3, then the heating time of the aqueous solution contained in the tank corresponding to the sum of the second time value, t2, and third time value, t3, is calculated on the basis of the second temperature of the aqueous solution, T2, measured.

[0019] Thus, measuring a second temperature, T2, allows for optimization of the heating time of the aqueous solution based on an initial temperature, T2, of the aqueous solution in the reservoir. When the second temperature, T2, is higher than a predetermined third temperature, T3 (for example, T3 equal to 0 °C), the heating time is calculated based on the measured temperature of the second aqueous solution, T2. This optimizes the heating time of the aqueous solution.

[0020] According to an advantageous implementation, the process of bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with an internal combustion engine is such that the heating of the aqueous solution contained in the tank is restarted after a stop of the vehicle, if the measurement of a fourth temperature, T4, of the aqueous solution taken at the restart of the vehicle and a second travel time, tr2, or remaining travel time, are sufficient and this taking into account the duration of the maintenance of said first temperature of the aqueous solution, T1, before the stop.

[0021] Thus, it is possible to take into account vehicle stops not initially planned during the implementation of the bio-decontamination process.

[0022] According to an advantageous implementation, the process of bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with a thermal engine is such that the heating of the aqueous solution contained in the tank is continued during the stopping of the vehicle for a fourth value of time, t 4.

[0023] Thus, it is possible to continue the bio-decontamination process using the vehicle's available electrical and / or thermal energy, even when the vehicle is switched off. This is particularly true in the case of a plug-in hybrid vehicle.

[0024] According to an advantageous implementation, the process of bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with an internal combustion engine is such that the tank containing the aqueous solution includes a biocide.

[0025] Thus, it is possible, by using a tank containing a biocide, to reduce the number of treatment cycles required.

[0026] According to an advantageous implementation, the process of bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with an internal combustion engine is such that it is repeated at least every six months.

[0027] According to an advantageous implementation, the aqueous solution is heated by means of an electric heater and / or by means of a coolant from a vehicle engine.

[0028] This allows us to choose from several types of heat sources to heat the aqueous solution, making the invention flexible in its implementation.

[0029] According to an advantageous implementation, the heating power supplied by the electric driver is modulated according to the first journey time, t r1.

[0030] Modulating the heating power supplied by the electric heater allows control over the temperature evolution of the aqueous solution during heating. For example, one can begin by applying a high heating power to quickly reach the initial temperature, then reduce the heating power to avoid unnecessarily overheating the aqueous solution during the third time value, t3, which would generate energy losses that are best avoided.

[0031] According to the invention, the third time value, t 3, is greater than 20 minutes, preferably greater than 75 minutes, and even more preferably greater than 105 minutes.

[0032] This ensures the destruction of some, or even all, types of microorganisms that may be found in the aqueous solution, thus guaranteeing the effectiveness of the bio-decontamination.

[0033] The invention also provides a computer-readable storage medium comprising instructions for the bio-decontamination of an aqueous solution contained in a tank on board a vehicle which, when executed by a computer, lead the computer to implement the steps of a process as defined above.

[0034] A bio-decontamination system for an aqueous solution contained in a tank on board a motor vehicle with an internal combustion engine is also provided, said system comprising at least one aqueous solution tank, a heating means and an electronic control unit (ECU) capable of receiving information encoded in the navigation system or GPS system, said information comprising at least a first travel time, t r1, said electronic control unit being capable of controlling the start or stop of the heating means, said heating means being capable of raising the aqueous solution contained in the tank to a temperature of at least 60°C during a third time value, t 3.

[0035] According to an advantageous embodiment of the preceding embodiment, the bio-decontamination system for an aqueous solution contained in a tank on board a motor vehicle with an internal combustion engine is such that it includes at least one temperature sensor capable of measuring the temperature of the aqueous solution contained in the tank.

[0036] According to an advantageous embodiment, the bio-decontamination system for an aqueous solution contained in a tank on board a motor vehicle with an internal combustion engine is such that it includes at least one level sensor for the aqueous solution contained in the tank.

[0037] According to an advantageous embodiment, the bio-decontamination system for an aqueous solution contained in a tank on board a motor vehicle with an internal combustion engine is such that it comprises a tank containing a biocide.

[0038] The bio-decontamination system for an aqueous solution contained in a tank on board a motor vehicle with a thermal engine is obviously capable of implementing the bio-decontamination process for an aqueous solution contained in a tank on board a motor vehicle with a thermal engine as described above.

[0039] Table 1 presents examples of heat treatment time calculations related to the use of the process according to the invention for different types of microorganisms. These treatment times are a function of the initial temperature of the aqueous solution for a volume of aqueous solution contained in the vehicle's tank of 20 L. The specific heat of the aqueous solution was assumed to be equal to that of pure water (4182 J / (K*K)). A 100% heat transfer between the heat source and the aqueous solution to be treated was assumed for these calculations. The heat source consists of a heat exchanger with the engine coolant, having a heat output of 1500 W. Temp. init. Type of microorganisms Lethal temperature Lethal time (min) at Lethal Temp. Time to reach lethal temperature (min) Total time (min) 10 °C Bacterium Escherichia coli 60 °C 105 46 151 10 °C Bacterium Pseudomonas aeruginosa 60 °C 75 46 121 10 °C Bacterium Staphylococcus aureus 63 °C 20 49 69 10 °C Spore Fungal spore 76 °C 22 61 83 20 °C Bacterium Escherichia coli 60 °C 105 37 142 20 °C Bacterium Pseudomonas aeruginosa 60 °C 75 37 112 20 °C Bacterium Staphylococcus aureus 63 °C 20 40 60 20 °C Spore Fungal spore 76 °C 22 52 74 30 °C Bacterium Escherichia coli 60 °C 105 28 133 30 °C Bacterium Pseudomonas aeruginosa 60 °C 75 28 103 30 °C Bacterium Staphylococcus aureus 63 °C 20 31 51 30 °C Spore Fungal spore 76 °C 22 43 65

[0040] Data presented in Table 1 show that the lethal temperature to which the aqueous solution to be treated must be heated and the holding time at this temperature depend on the type of microorganism to be destroyed. A temperature, T1, of at least 60°C ensures effective decontamination for certain bacteria. The total treatment time, or first time value, t1, is equal to the sum of the time to reach the lethal temperature, T1, or second time value, t2, and the lethal time, or third time value, t3. The second time value, t2, depends on the volume of the aqueous solution to be treated and its initial temperature. In the absence of knowledge of the volume of solution in the tank and the temperature of the aqueous solution, it can be assumed by default that the tank contains a maximum volume of aqueous solution, said solution being at a temperature of 0°C.If the travel time calculated by the GPS is at least equal to the total decontamination treatment time, or the first time value, t1, then the bio-decontamination process can be initiated, considering a maximum volume of aqueous solution at a temperature of 0°C. This treatment time can be reduced by knowing the volume of aqueous solution, for example, by measuring the liquid level in the tank, or by measuring the initial temperature.

[0041] Data presented in Table 1 also show that the third time value, t3, must be at least 20 minutes to destroy certain types of microorganisms. In other words, if the aqueous solution is not maintained at a temperature above T1 for a sufficient duration, bio-decontamination will not be effective. Furthermore, the third time value, t3, must be greater than 75 minutes, and preferably greater than 105 minutes, to destroy most or all of the listed types of microorganisms.

[0042] The effectiveness of bio-decontamination by heating an aqueous solution is measured using the spread plate technique. This technique allows for the enumeration of microorganisms, particularly bacteria, in a sample, thus facilitating precise quantification. It provides information on the number of microorganisms present in the sample. The spread plate technique involves taking a 0.1 ml aliquot of the aqueous solution to be analyzed, possibly diluted, using a micropipette and transferring it to a fresh agar plate. This transfer is performed using a spreader, which is a sterilized spreader with a smooth metal or glass surface. A small amount of microorganisms suspended from the solution to be analyzed, possibly diluted, is then applied to the fresh agar plate.A successful spread plate will have a countable number of isolated microorganism colonies uniformly distributed across the plate. Thus, the viability of microorganisms before and after heat treatment can be compared, since only viable microorganisms, particularly viable bacteria, will form a colony on the agar plate. If the heat treatment is effective, no or very few colonies will develop on the gel. The unit of measurement usually used is CFU / ml (or colony-forming units per milliliter). Bio-decontamination is considered sufficient or effective if, under identical operating measurement conditions, a decrease of at least 90% in the number of counted colonies is observed before and after application of the bio-decontamination process according to the invention to the aqueous solution to be treated.

[0043] The spread plate technique involves using a sterilized spreader with a smooth metal or glass surface to apply a small amount of microorganisms, particularly bacteria, suspended in an aqueous solution onto a plate. The plate should be dry and at room temperature so the gel can more easily absorb the microorganisms. A successful spread plate will have a countable number of isolated microorganism colonies evenly distributed across the plate. This spread plate technique procedure includes the following steps: 1. Prepare a series of dilutions from the aqueous solution to be analyzed. 2. Pipette 0.1 mL of the desired dilution series onto the center of an agar plate. 3. Soak the L-shaped glass spreader in alcohol. 4. Heat-sterilize the glass spreader on a Bunsen burner. 5. Spread the sample evenly onto the agar surface using the sterile glass spreader, while simultaneously rotating the Petri dish underneath. 6. Incubate the plate at 37°C for 24 hours. 7. Calculate the CFU value of the analyzed aqueous solution. After counting the colonies, multiply the number of colonies by the appropriate dilution factor to determine the number of CFU / mL in the analyzed aqueous solution.

Claims

1. Method for bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with a combustion engine, said method comprising the following steps: • Obtaining the information encoded in a navigation system or GPS system, said information including at least an initial journey time, tr1; • If the first travel time, tr1, is greater than a first time value, t1, initiating a heating of the aqueous solution contained in the tank in order to reach a first temperature of the aqueous solution, T1, at least equal to 60°C during a second time value, t2, • Maintaining the aqueous solution at at least said first temperature, T1, for a third time value, t3, greater than 20 minutes, preferably greater than 75 minutes, and even more preferable greater than 105 minutes.

2. Method according to claim 1, such that it comprises a step for measuring the level of the aqueous solution in the tank, if the level of the aqueous solution measured is less than the maximum level that can be contained in the tank, then the heating time of the aqueous solution contained in the tank being the sum of the second time value, t2, and third time value, t3, is calculated on the basis of the actual volume of aqueous solution, said actual volume of aqueous solution being calculated on the basis of the measured level value of the aqueous solution.

3. Method according to any of the preceding claims, such that it comprises a step for measuring a second temperature of the aqueous solution, T2, if the second temperature of the aqueous solution, T2, measured is greater than a third temperature, T3, then the heating time of the aqueous solution contained in the tank being the sum of the second time value, t2, and third time value, t3, is calculated on the basis of the second temperature of the aqueous solution, T2, measured.

4. Method according to any of the preceding claims, such that the heating of the aqueous solution contained in the tank is restarted after the vehicle is stopped, if the measurement of a fourth temperature, T4, of the aqueous solution taken at the restart of the vehicle and a second travel time, tr2, or remaining travel time, are sufficient, taking into account the duration of the maintenance of said first temperature of the aqueous solution, T1, before the stop.

5. Method according to any one of claims 1 to 3, such that the heating of the aqueous solution contained in the tank is continued when the vehicle is stopped for a fourth time value, t4.

6. Method according to any of the preceding claims, such that the tank containing the aqueous solution comprises a biocide.

7. Method according to any of the preceding claims, such that it is repeated at least every six months.

8. Method according to any one of the preceding claims, wherein the aqueous solution is heated by means of an electric heater.

9. Method according to any one of the preceding claims, wherein the aqueous solution is heated by means of a coolant of an engine of the vehicle.

10. Method of claim 8, wherein the heating power provided by the electric driver is modulated as a function of the first travel time, tr1.

11. A computer-readable storage medium comprising instructions for bio-decontamination of an aqueous solution contained in a tank on board a vehicle which, when executed by a computer, cause the computer to perform the steps of the method according to any one of claims 1 to 10.