WO2022180069A1

WO2022180069A1 - System and method for the bio-decontamination of an aqueous solution held in a tank on board a motor vehicle having a combustion engine

Info

Publication number: WO2022180069A1
Application number: PCT/EP2022/054475
Authority: WO
Inventors: Stéphane Leonard; Laurent Duez
Original assignee: Plastic Omnium Advanced Innovation And Research
Priority date: 2021-02-26
Filing date: 2022-02-23
Publication date: 2022-09-01
Also published as: EP4298334A1; LU102580B1

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, t_r1; • If the first journey time, t_r1, 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

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

The invention relates to the field of motor vehicles with heat engines such as cars for example. The invention relates more particularly to a process for the bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with a combustion engine, more particularly a turbocharged gasoline engine with direct injection, and a system for the bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with a combustion engine, more particularly a turbocharged gasoline engine with direct injection, capable of implementing said method. The invention is intended to be used in particular in the field of the injection of water into the air intake circuit of the engine of a vehicle with a 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 NO _x , but also to increase performance, for example, of a gasoline engine by reducing knock sensitivity.

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 a malfunction of the system which can go as far as breakdown as well as to a clogging of the filters arranged in the water injection system. To avoid such contamination or to eradicate contamination already present, one could think of using chemicals. However, injecting such chemicals into the combustion chamber can cause other problems. It is therefore essential to have an aqueous solution with very little charge, preferably free of bacteria, algae, fungi or other microorganisms within the tank.

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

The aim of the invention is in particular to overcome these drawbacks of the prior art. More specifically, one objective of the invention, in at least one of its embodiments, is to implement a process for the bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with a heat engine by heating, said method having to allow bio-decontamination which is sufficient. Another objective of the invention, in at least one of its embodiments, is to provide a system for the bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with a heat engine capable of implements said process.

In accordance with a particular mode of implementation, the invention relates to a process for the bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with a heat engine.

According to the invention, such a method comprises the following steps:

Encoding of the place of destination in a navigation system or GPS system, • Obtaining information calculated by the navigation system or GPS system, said information comprising at least a first journey time, t _ri ;

• If the first travel time, t _ri , is greater than a first time value, ti, triggering heating of the aqueous solution contained in the tank in order to reach a first temperature of the aqueous solution, T i, at least equal to 60°C during a second time value, h

• Maintaining the aqueous solution at at least said first temperature, Ti, for a third time value, Î _3.

The general principle of the invention is based on the use of the first travel time, t _ri , calculated by the navigation system or GPS system, said first travel time, t _ri , conditioning the start of heating or not of the aqueous solution contained in the tank in order to perform bio-decontamination by heating the aqueous solution. Bio decontamination times by heating being relatively long, of the order of an hour at least depending on the quantity of aqueous solution present in the tank and the type of microorganisms to be eliminated, it is therefore necessary to have a sufficient rolling time to carry out the bio-decontamination by heating the aqueous solution. Furthermore, a bio-decontamination by heating the aqueous solution being carried out for too short a time could even have the opposite effect and increase the proliferation of bacteria if the cycle is stopped when the water is at around 37°C. , a bio-decontamination cycle is carried out only when the travel time estimated by the navigation system or GPS system exceeds the time necessary to kill the microorganisms having a lethal temperature in solution of at least 60°C. This duration can also be adjusted according to the initial temperature of the aqueous solution contained in the tank or according to the volume of aqueous solution contained in the tank, said volume being measured for example using a level sensor.

The term "bio-decontamination" is intended to denote the fact that Ton destroys at least 90% of the microorganisms present in the aqueous solution, said microorganisms having a lethal temperature of at least 60°C.

The expression "lethal temperature of a microorganism" is intended to designate the temperature to which the aqueous solution must be brought for a certain period of time to kill said microorganism. Said time period is preferably less than four hours, more preferably less than three hours, most preferably less than two hours.

Advantageously, the process for the bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with a heat engine is such that it comprises a step of measuring the level of the aqueous solution in the tank, if the level of the measured aqueous solution is less than the maximum level of aqueous solution that can be contained in the reservoir, then the duration of the heating of the aqueous solution contained in the reservoir corresponding to the sum of the second time value, h and third time value , t ₃ , 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 measured aqueous solution.

The expression "actual volume of the aqueous solution" is intended to designate the volume of aqueous solution present in the reservoir.

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 step of heating the aqueous solution of the method of bio-decontamination by heating as a function of the quantity of aqueous solution to be treated. According to an advantageous implementation, the process for the bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with a thermal engine is such that it comprises a step of measuring a second temperature of the aqueous solution , T ₂ , if the second temperature of the aqueous solution, T ₂ , measured is greater than a third temperature, T ₃ , then the duration of the heating of the aqueous solution contained in the reservoir corresponding to the sum of the second time values , t ₂ , and third time value, t3, is calculated on the basis of the second temperature of the aqueous solution, T ₂ , measured.

Thus, the measurement of a second temperature, T ₂ , allows an optimization of the duration of the heating of the aqueous solution as a function of a starting temperature, T ₂ , of the aqueous solution contained in the tank. Thus when the second temperature, T ₂ , is greater than a third predetermined temperature, T ₃ , for example T ₃ equal to 0°C, the duration of the heating time is calculated on the basis of the second temperature of the aqueous solution, T ₂ , measured. This makes it possible to optimize the heating time of the aqueous solution.

According to an advantageous implementation, the process for the bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with a combustion engine is such that the heating of the aqueous solution contained in the tank is restarted after a stoppage of the vehicle, if the measurement of a fourth temperature, T ₄ , of the aqueous solution taken when the vehicle is restarted and a second journey time, t _r2 , or remaining journey time, are sufficient, taking into account the duration of the maintaining said first temperature of the aqueous solution, Ti, before stopping.

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

According to an advantageous implementation, the process for the bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with a combustion engine is such that the heating of the solution aqueous contained in the reservoir is continued when the vehicle is stopped for a fourth time value,

Thus, it is possible to continue the bio-decontamination process on the basis of the electric and/or caloric energy available from the vehicle despite the shutdown of the latter. And this more particularly in the case of a plug-in hybrid vehicle.

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

Thus, it is possible by using a tank comprising a biocide to reduce the number of treatment cycles required.

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

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. It is thus possible to choose from among several types of heat sources for heating the aqueous solution, which makes the invention flexible in its implementation.

According to an advantageous implementation, a heating power supplied by the electric heater is modulated as a function of the first travel time, t _ri . The modulation of the heating power provided by the electric heater makes it possible to control the evolution of the temperature of the aqueous solution during its heating. It is thus possible, for example, to begin by imposing a high heating power in order to quickly reach the first temperature, then to lower the heating power so as not to heat the aqueous solution unnecessarily too much during the third time value, t ₃ , this which would generate energy losses which it is better to avoid.

According to an advantageous implementation, the third time value, Î _3, is greater than 20 minutes, preferably greater than 75 minutes, and even more preferably greater than 105 minutes.

This ensures the destruction of some of the types of microorganisms that may be found in the aqueous solution, or even all types of microorganisms, which guarantees the effectiveness of bio-decontamination.

There is also provided according to the invention 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 it to implement the steps of a method as defined in the foregoing.

Provision is also made for a system for the bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with a heat engine, said system comprising at least one tank of aqueous solution, 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 journey time, t _ri , said electronic control unit being capable of controlling the starting or stopping of the means of heating, said heating means being capable of bringing the aqueous solution contained in the reservoir to a temperature of at least 60° C. for a third time value, t ₃ . According to an advantageous embodiment of the previous embodiment, the system for bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with a heat engine is such that it comprises at least one temperature sensor capable of measuring the temperature of the aqueous solution contained in the reservoir.

According to an advantageous embodiment, the system for the bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with a heat engine is such that it comprises at least one level sensor for the aqueous solution contained in the tank . According to an advantageous embodiment, the system for the bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with a combustion engine is such that it comprises a tank comprising a biocide.

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

Table 1 presents examples of calculations of heat treatment times linked to the use of the method 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 tank of the vehicle of 20L. The specific heat of the aqueous solution was considered to be equal to that of pure water (4182 J/(K*Kg)). A heat transfer of 100% between the heat source and the aqueous solution to be treated was considered for the realization of these calculations. The heat source consists of an exchanger with the engine coolant having a heat output of 1500 W.

It is observed from the data presented in Table 1 that the lethal temperature to which the aqueous solution to be treated must be brought and the holding time at this temperature depend on the type of microorganism to be destroyed. A temperature, Ti, of at least 60° C. makes it possible to obtain effective decontamination for certain bacteria. The total treatment time or first time value, ti, is equal to the sum of the time to reach the lethal temperature, Ti, or second time value, h and the lethal time or third time value, t _3. The second time value, h is a function of the volume of the aqueous solution to be treated and of the initial temperature of the latter. In the absence of knowledge of the volume of solution in the reservoir and of the temperature of the aqueous solution, it can be considered by default that the reservoir 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 time of the decontamination treatment or first time value, ti, then the bio-decontamination process can be initiated by 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 by measuring the level of liquid present in the reservoir, for example, but also by measuring the initial temperature. It is also observed from the data presented in Table 1 that the third time value, t ₃ , must be at least greater than 20 minutes to destroy certain types of microorganisms. In other words, if the aqueous solution is not maintained at a temperature above Ti for a sufficiently long time, the bio-decontamination will not be effective. We also observe that the third time value, t ₃ , must be greater than 75 minutes, and even preferably greater than 105 minutes, to destroy most or all of the types of microorganisms listed.

The measurement of G efficiency of the bio-decontamination by heating the aqueous solution is carried out by the so-called spread plate technique. This technique makes it possible to count the microorganisms, more particularly the bacteria, in a sample and therefore facilitates the precise quantification of the microorganisms. It provides information on the number of microorganisms present in the sample. This spread plate technique consists of 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 operation is carried out using a spreader and consists of using a sterilized spreader with a smooth metal or glass surface to apply a small quantity of microorganisms in suspension from the solution to be analyzed, possibly diluted, on the fresh agar plate. A successful streak plate will have a countable number of isolated microorganism colonies evenly distributed across the plate. Thus the viability of the microorganisms before and after heat treatment can be compared since only the viable microorganisms, more particularly the viable bacteria, will form a colony on the agar plate. If the heat treatment is effective, no or very few colonies will grow on the gel. The unit of measurement usually used is cfu/ml (or colony forming units per milliliter). It is considered that a bio-decontamination is sufficient or effective if, with equal operating conditions of measurement, a reduction in the number of colonies counted by at least 90% is observed before and after application of the bio-decontamination method according to the invention to the aqueous solution to be treated.

The spread plate technique involves using a sterilized spreader with a smooth metal or glass surface to apply a small amount of microorganisms, specifically bacteria, suspended in an aqueous solution onto a plate. The plate must be dry and at room temperature so that 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. Make a series of dilutions from the aqueous solution to be analyzed. 2. Pipette 0.1 ml of the desired dilution series onto the center surface of an agar plate.

3. Dip the L-shaped glass spreader in alcohol.

4. Heat sterilize the glass spreader over a Bunsen burner.

5. Spread the sample evenly over the surface of the agar using the sterile glass spreader, carefully rotating the Petri disk underneath at the same time.

6. Incubate the plate at 37°C for 24 hours.

7. Calculate the CFU value of the analyzed aqueous solution. Once the colonies have been counted, multiply the number of colonies by the appropriate dilution factor to determine the number of cfu/ml in the aqueous solution being analyzed.

Claims

1. Process for the bio-decontamination of an aqueous solution contained in a tank on board a motor vehicle with a heat engine, said process comprising the following steps:

• Obtaining information encoded in a navigation system or GPS system, said information comprising at least a first journey time, t _ri ;

• If the first travel time, t _ri, is greater than a first time value, ti, triggering a heating of the aqueous solution contained in the tank in order to reach a first temperature of the aqueous solution, Ti, at the least equal to 60°C during a second time value, h,

2. Method according to claim 1, such that it comprises a step of measuring the level of the aqueous solution in the reservoir, if the level of the measured aqueous solution is lower than the maximum level that can be contained in the reservoir, then the duration of the heating of the aqueous solution contained in the reservoir corresponding to the sum of the second time value, h, and third time value, t ₃ , is calculated on the basis of the actual volume of aqueous solution, said actual volume of aqueous solution being calculated based on the level value of the measured aqueous solution.

3. Method according to any one of the preceding claims, such that it comprises 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 duration of the heating of the aqueous solution contained in the tank corresponding to the sum of the second time value, h and third time value, t ₃ , is calculated on the basis of the second temperature of the aqueous solution, T2, measured.

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

5. Method according to any one of claims 1 to 3, such that the heating of the aqueous solution contained in the reservoir is continued when the vehicle is stopped for a fourth time value, t _4.

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

7. Process according to any one of the preceding claims, as repeated at least every six months.

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

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

10. Method according to claim 8, in which a heating power supplied by the electric heater is modulated as a function of the first travel time, t _{ri .}

11. Method according to any one of the claims above, in which the third time value, t ₃ is greater than 20 minutes, preferably greater than 75 minutes, and even more preferably greater than 105 minutes.

12. 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, leads the computer to implement the steps of the method according to any one of the preceding claims.