WO2024108283A1

WO2024108283A1 - Method for managing an internal combustion engine (ice) and water level sensor system

Info

Publication number: WO2024108283A1
Application number: PCT/BR2023/050397
Authority: WO
Inventors: Toshizaemon NOCE
Original assignee: FCA Fiat Chrysler Automoveis Brasil Ltda
Current assignee: FCA Fiat Chrysler Automoveis Brasil Ltda
Priority date: 2022-11-21
Filing date: 2023-11-17
Publication date: 2024-05-30
Anticipated expiration: 2025-05-21

Abstract

A method of managing an internal combustion engine (2) of a vehicle (1) in transit through a flooded region is described. The method comprising the steps of: to activate the pressure sensor (PS); to compare the instantaneous pressures (PSi) measured by the pressure sensor (PS) with an average pressure value (PSm), being the average pressure value (PSm) calculated by the engine control unit (ECU) using an arithmetic average between the pressure readings previously registered; to identify a negative pressure peak of an instantaneous pressure (PSi) in relation to the average pressure value (PSm); and to define by the engine control unit (ECU) a second limit (L2rpm) for the engine (2) rotation speed. The engine (2) rotation speed remains limited to the second rotation speed limit (L2rpm) as long as the instantaneous pressure (PSi) is lower than the average pressure value (PSm). A sensor system for carrying out the method is also described, which combines a sensor (WS) that defines an alert level for the water depth of a flooded region with the pressure sensor (PS) of the engine intake, enabled by the sensor (WS) to define a critical level of the water depth.

Description

METHOD FOR MANAGING AN INTERNAL COMBUSTION ENGINE (ICE) AND WATER LEVEL SENSOR SYSTEM

[001] The present invention relates to a method for managing an internal combustion engine (ICE) of a vehicle in conditions of traffic through a flooded region, as well as a water level sensor system of the flooded region, in particular, at risk from the so-called hydraulic lock.

State of art

[002] The so-called hydraulic lock, or Hydrolock, is a phenomenon of entering water or another incompressible fluid inside the cylinders of an internal combustion engine (ICE). In the most common cases, this phenomenon occurs when a vehicle crosses a flooded region, for example, during an intense rain. If the level of accumulated water on the ground is very high in relation to the height of the vehicle, it is possible that a certain amount of water unduly enters in the intake manifold and then into the cylinders through the intake valve, sucked in during the engine's suction phase. In the next compression phase, the piston should compress the air/fuel mixture but, due to the presence of non- compressible water, the piston is mechanically prevented from rising, totally or partially, leading to catastrophic damage to the piston, connecting rod and crankshaft, when not on other engine's mechanical components.

[003] For the hydraulic lock phenomenon to occur, the amount of water entering the cylinder must be greater than the internal volume of the cylinder with the piston at its top dead center, that is, the amount of water must be sufficient to prevent the piston from fully ascending. In the case of a smaller amount of water entering, the burning of the air/fuel mixture and the consequent temperature increase inside the cylinder leads to the vaporization of water and the exit of this water vapor from the inside of the cylinder, during the exhaust phase of gases. In this case, combustion may not be ideal but there is no severe and potentially irreparable compromise to the internal combustion engine (ICE).

[004] Usually, when a driver finds himself in a risky situation in which the water level in the streets or roads is higher than a certain level, the driver's intuitive reaction is to drive the vehicle as quickly as possible so as to avoid this risky situation. In these cases, this leads the internal combustion engine (ICE) to work at high speed or high rpm, resulting in the aspiration of large quantities of air and water and, thus, a catastrophic failure of the internal combustion engine (ICE) due to the so-called hydraulic lock, with consequent locking and loss of the engine.

[005] Some devices and methods intended to avoid hydraulic lock are already known in the art by detecting, via sensor, the water level in a flooded region through which the vehicle travels. [006] Document US 10255782 teaches a device and a method for detecting flooding region by a vehicle. The vehicle includes an engine, a humidity sensor, a GPS receiver for determining the vehicle's location, a communication module and a control module. The control module is able to collect, via the humidity sensor, a measurement of the humidity inside the engine and collect the humidity level at the location of the vehicle. The control module is also able to identify a flooding event when the humidity measurement exceeds a certain threshold in the humidity level at a predetermined threshold and records the flooding event on a remote server via the communication module. Although this document identifies that the vehicle is/was in a flooded region, it does not propose any way to avoid damage to the vehicle, limiting itself to recording the fact.

[007] Document US 9975499 teaches a motor vehicle that includes an imaging device comprising at least one camera. The device is operable to provide a wide image to the driver of the vehicle, this image being of at least a portion of the exterior surface of the vehicle that is exposed to liquid during flooding. The wide image is taken to allow the driver to determine whether the liquid level is below a defined level. As proposed, this solution simply indicates to the driver that the vehicle is moving or is about to move through a flooded region whose water depth is above a safe level for the vehicle. This solution does not offer any form of operational assistance to the driver nor does it provide a more precise parameter regarding the critical situation of the liquid level around the vehicle.

[008] Document EP 2341368 teaches a recognition system based on ultrasound sensors for detecting distance in relation to objects in a longitudinal direction and/or in a transverse direction in relation to the vehicle. The sensors are arranged in a position partially above the flooding for recognizing it (the flooding). The control units evaluate the sensor signals in relation to flooding (via signal response time). The control units recognize whether the sensors are in air or water depending on the response and evaluate the signal characteristics, echo duration, number of echoes and the occurrence of acoustic short circuits (submerged sensors). An independent object comprises a method for recognizing flooding in a vehicle. The sensors are preferably part of the vehicle's parking system, with up to four sensors provided in the front bumper and up to 4 in the rear bumper. This system is limited to indicating the vehicle's traffic condition in a flooded region only.

[009] Document US 2018348753 teaches a system for detecting the level of a flooding. This includes at least one sensor and one interface. The sensor detects the depth of an area with accumulated water in the vicinity of the vehicle and then communicates the depth of the area with accumulated water to the interface. The sensor, in one embodiment, is a laser sensor but, in other embodiments, the sensor may be a LIDAR sensor, a LADAR sensor, a radar or a sonar-type sensor. [0010] Document GB 2564204 teaches a vehicle computer that includes a processor programmed to execute instructions which include receiving a first measurement from a tire pressure sensor at a first time, receiving a second measurement from a tire pressure sensor in a second moment and determine the road waterlogging based on the differences between pressure measurements. The water depth is determined and an alert is issued if the vehicle is not operating autonomously. Preferably, data from an exhaust gas temperature sensor, images from a camera showing highway characteristics and a remote server are also received. The ground clearance of a suspension system can be increased when water is detected or a new route can be recommended.

[0011] Document GB 2486458 teaches a vehicle that includes a hydrostatic pressure sensor for measuring water depth. The sensor can communicate wirelessly with the vehicle via a tire pressure measurement protocol and it can be positioned in the engine bay. The orientation of the vehicle can also be calculated. The hydrostatic pressure sensor can be activated upon detection of a water level detected from the parking sensor positioned on the front and/or rear bumpers of the vehicle. The solution as proposed fails to link the activation of the crossing detection system, through a flooded region, with the parking sensor, which is only activated in low-speed driving conditions.

[0012] Document GB 2529459 describes a method for automatically controlling the speed of a vehicle crossing a water flooding. The method comprises in detect the vehicle entering a in water flooding obstacle. The method further comprises to determine the depth of water near the vehicle based on readings and information received from, for example, one or more sensors or other components of the vehicle. Thus, when the depth exceeds a predetermined depth, the method further comprises automatically reducing the speed of the vehicle such that the bow wave created in the water by the vehicle, which propagates in front of the vehicle and in a direction of travel of the vehicle. Vehicle speed can still be controlled automatically in relation to the progress of the bow wave. A method for implementing this methodology is also described.

[0013] Despite the control of the vehicle's travel speed and, more in particular due to the bow wave generated by the vehicle's displacement, allowing a reduction in the risk of hydraulic lock, the solution proposed in document GB 2529459 is not free from disadvantages. In fact, this vehicle speed control solution only applies to situations in which the water flooding to be crossed is in extremely calm conditions, that is, without waves, without current or without other interference in the bow wave, in addition to the displacement of the vehicle itself (which generates the bow wave) through the flooded region. Furthermore, the speed control solution can be effective, but it is limited to these absolutely particular conditions of the flooded region through which the vehicle travels, being technically unfeasible in adverse conditions. [0014] In general, the solutions of the art are not able to properly manage the movement of a vehicle through a flooded region, especially when the water depth is dynamically irregular for geographical environmental reasons and/or due to traffic of competing vehicles, among others.

[0015] Therefore, an object of the present invention constitutes a system for detecting and managing the risk of hydraulic lock when a vehicle moves through a flooded region.

[0016] More in particular, an object of the invention is a system for detecting and managing the risk of hydraulic lock when a vehicle moves through a flooded region, in particular when the water depth of the flooded region is dynamically irregular.

[0017] Another object of the invention is a system that is easy to implement in vehicles, preferably using previously existing components and devices.

[0018] Another object of the invention is a method aimed at managing an internal combustion engine when the vehicle moves through a flooded region and, particularly, when the water flooding is irregular.

Synthesis of the Invention

[0019] The present invention comprises a method...

[0020] The present invention comprises a system...

Brief Description of Figures

[0021] The invention will be better understood from the detailed description of a preferred and non-limiting form of embodiment, which is made with the support of the attached figures, brought for illustrative and non-limiting purposes, in which:

- figure 1 is a schematic view of a motor vehicle, according to the invention and

- figure 2 is a diagram illustrating the steps of the method of the invention.

Preferred Embodiment of the Invention

[0022] In accordance with the attached figures, with 1 a vehicle is schematically indicated as a whole. In a very simplified way, the vehicle 1 comprises an internal combustion engine 2 which, in a known way, receives fuel from a reservoir (not illustrated) and injects it, in defined quantities, into each cylinder (not illustrated) according to the power demand established by the driver and according to the amount of fresh air admitted/sucked into the intake manifold (not illustrated). The air intake system, as also known, draws in a quantity of fresh air as each of the cylinders moves from the top dead center (TDC) position to the bottom dead center (BDC) position, in the intake stage of the cycle motor. As the maximum and minimum volumes of each cylinder are fixed, the amount of fresh air drawn in or air demand, varies, depending on the engine speed (RPM). Furthermore, the amount of air sucked in also varies depending on the position of the butterfly valve 3, located in the air intake duct, downstream of the air filter (not illustrated).

[0023] In electronically controlled vehicles, the amount of fuel is controlled by an electronic control unit (ECU) (not illustrated) intended to result in the most complete combustion possible and, therefore, aimed at obtaining the greatest possible amount of energy from burning with the least amount possible from polluting residues. In addition to the electronic control unit (ECU), said vehicles comprise other sensing and processing devices, among which can be mentioned the pressure sensor (PS) usually installed adjacent to said butterfly valve 3, preferably downstream of said butterfly valve 3, which allows the electronic control unit (ECU) to control more accurate on the amount of fresh air admitted into each cylinder of the engine 2, complementing and/or replacing the mass airflow sensor (MAF) which quantifies the flow and eventually the temperature of the air admitted into the engine. In some embodiments, a second pressure sensor is also provided, but installed upstream of said butterfly valve. In vehicles equipped with an automatic or semi-automatic transmission, the transmission control unit (TCU) is responsible for gears changing, depending on the power demand required by the driver as well as depending on the vehicle's operating conditions, such as engine rotation speed (rpm), pressure on the accelerator pedal, instantaneous speed, among other parameters known by the technicians in the sector.

[0024] As noted by the inventors, the presence of water in the inlet nozzle 5 of the air filter housing 4 (illustratively shown, for clarity, in figure 1 outside the engine compartment) causes a pressure reading peak measured by the pressure sensor (PS). More in particular, the presence of water causes a negative pressure peak in relation to an average value of the previously measured pressures. In practice, it is not possible to define just one origin for the aforementioned pressure peak, but a combination of several factors, which result from the local conditions of the vehicle's movement.

[0025] A first justification for the aforementioned pressure peak/variation detected by the pressure sensor (PS) is the change of what is being sucked in by engine 2. Under normal traffic conditions, the pressure sensor (PS) only detects a low pressure (in relation to local atmospheric pressure) generated by air intake by the engine. In the case of traffic through a flooded region, what is sucked in by the engine becomes a mixture of air and water, whose apparent density is greater, or potentially much greater, than the density of air. Therefore, this change in what is aspirated leads to reductions in the pressures detected - absolute and/or relative - by the pressure sensor (PS). A second justification, which arises from the first one, is the loss of performance of the air filter mesh, making it difficult for atmospheric air to pass through it. Since the external surface of the filter element is normally already contaminated by previously filtered impurities and dirt, said impurities mix with the water that enters the system further clogging the filter mesh. This effect is even more relevant when the vehicle usually travels through large cities and industrial centers, where the air carries particles of all kinds.

[0026] Another further justification for the pressure variation detectable by the pressure sensor is an instantaneous reduction, or possibly a total occlusion, in the area of the inlet nozzle 5 capable of admitting fresh external air. Since flooded regions in urban centers are generally the result of intense rain, the possibility of a specific flood presenting a flat and a good water depth is almost zero. The movement of other vehicles through the same flooded region, as well as the displacement of water across the local embossment, leads to the formation of waves, peaks and valleys that can temporarily obstruct, totally or partially, the inlet nozzle 5, causing negative pressure peaks in the sensor pressure (PS).

[0027] Once the electronic control unit (ECU) detects a peak in the pressures measured downstream of the butterfly valve 3, among others, the electronic control unit (ECU) understands that such a pressure peak is resulting from the presence of water in the inlet nozzle 5 of the air filter housing 4 and said water presence can damage the engine 2. More specifically, the pressure sensor (PS), arranged adjacent to the butterfly valve 3, is able to define a critical level of the water depth in relation to the inlet nozzle 5 of the air filter housing 4 as long as it is previously enabled by the sensor (WS) as well as informing the electronic control unit (ECU) about the occurrence of a negative pressure peak, indicating the presence of water.

[0028] Therefore, and in order to prevent the occurrence of hydraulic lock, the electronic control unit (ECU) immediately commands a reduction in the rotational speed (rpm) of engine 2 in order to reduce the demand for fresh air. In this way, by reducing the demand for fresh air by engine 2, any unwanted entry of water into the cylinders, in a potentially harmful volume, is automatically reduced. This way and even if a small volume of water enters the cylinders, as mentioned, the internal operating conditions of the cylinders allow this volume of water to be eliminated, in the form of water vapor through the exhaust of the engine 2, without causing any damage of greater intensity, as in the case of hydraulic lock.

[0029] In a particularly efficient form of carrying out the invention, the vehicle is also equipped with a sensor capable of determining the level of the water depth through which the vehicle moves or travels. Preferably, said sensor is a WS inductive sensor, indicating its physical contact with a water body, which is positioned close to the engine 2 of vehicle 1, that is, at the rear of the vehicle in the case of vehicles with rear engines or at the front of the vehicle in the case of vehicles with front engines. Regarding the WS sensor's position in relation to the ground, this vertical distance must be estimated/calculated depending on the particular characteristics of the vehicle 1, the arrangement of the inlet nozzle 5 of the air filter housing 4 inside the engine compartment, among others. In particular, the height of the WS sensor in relation to the ground must indicate a safe height, from which it becomes possible for a wave in the level of the water depth to reach said inlet nozzle 5 of the air filter housing 4.

[0030] Operationally, the WS sensor has a dual function, the first to identify that vehicle 1 is moving through a flooded region (alert level), thus activating the electronic control unit (ECU) to identify a pressure peak via the pressure sensor (PS) (critical level) and to carry out a first limitation on the rotational speed of engine 2, as well as to disable these controls by the electronic control unit (ECU) in the event that the indication of the water depth at the WS sensor level ceases. In other words, the sensor (WS) is able to define an alert level of the water depth of the flooded region in relation to the inlet nozzle (5) of the air filter housing (4) and is able to disable the alert level of the flooded region once contact of the water with the sensor (WS) ceases.

[0031] More specifically, the method of the present invention comprises, from the ignition of engine 2 of vehicle 1 (step SO), the capture and monitoring of the WS sensor signal (step S10) up to an indication of positive consistency in the signal generated by the WS sensor. Therefore, considering the assumptions of the invention regarding the irregularity of the water depth of a flooded region, specifically an urban region, it is possible to define a positive consistency in the WS sensor signal (step S20) as long as the WS sensor signal indicates the positive presence of water depth as a function of time (steps S201-S203).

[0032] To this end, the calculation subroutine (SR200) provides for starting a timer (step S201) with a pre-programmed measurement time, during which the time Tw is stored (step S202), during which the signal from the WS sensor indicates physical contact with water and the time Tnw, during which the WS sensor emits no signal or emits a signal merely indicative of being surrounded by air, i.e., not under water. In the next step (S203), if the time stored for the Tw signal is greater than the time stored for the Tnw signal, then it is considered that the WS sensor signal has positive consistency (see step S20) in relation to the presence of water above a level corresponding to the WS sensor quota. Otherwise, a negative indication from the WS sensor is considered, causing the main routine to continue collecting signals from the WS sensor but without any measure or action being taken by the electronic control unit (ECU).

[0033] Once subroutine SR200 has finished, the Tw and Tnw values are reset and it waits to be processed until the WS sensor emits any physical contact signal, according to step (S10).

[0034] When the processed WS signal is considered as indicative of positive consistency, that is, indicating that the WS sensor is under a water flooding during most the measurement time (see timer in S201), the electronic control unit (ECU) is informed of this potentially damaging condition for the engine 2 (step S30). Once the electronic control unit (ECU) receives a signal indicating that the vehicle is traveling through a flooded region (S20), the electronic control unit (ECU) makes a first reduction in the maximum engine 2 rpm Llrpm (step S40), for example limiting the engine rotation speed at a value below around 2000 rpms. In this way, the method of the invention provides a first protection against a possible hydraulic lock resulting from a greater height wave that may occur in the flooded traffic region.

[0035] Next, the electronic control unit (ECU) starts to capture (step S50) the instantaneous pressures (PSi) measured by the PS pressure sensor adjacent to butterfly valve 3 of engine 2 and to compare (step S60) such instantaneous pressures (PSi) collected with an average pressure value (PSm), calculated from an arithmetic average between previously recorded pressure readings. In other words, the comparison between a captured instantaneous pressure value (PSi) and the average pressure value (PSm) - calculated from the pressures measured prior to the positive indication of the WS sensor (S20) in order to detect a negative peak (pressure reduction) - provides an indication of the presence of water at the level of the inlet nozzle 5 of the air filter housing 4, that is, indicating a high risk of hydraulic lock. Once instantaneous pressure values (PSi) are detected that are lower, or much lower, than the average pressure values, prior to the event indicated by the WS sensor, the electronic control unit (ECU) makes a second limitation (step S70) on the maximum rotations (L2rpm) of the engine 2, since the current risk of hydraulic lock is absolutely concrete and real, thus demanding extreme engine protection measures. In practice, the second limit L2rpm of engine rotation speed is maintained as long as the condition of PSi < PSm (S60) remains, indicating that an undesirable and unacceptable quantity of water remains in the region close to the inlet nozzle 5 of the air filter housing 4, contaminating and/or obstructing the intake of fresh dry air to the engine 2.

[0036] In particular, the second engine rotation speed limit L2rpm is lower than the first engine rotation speed limit Llrpm and preferably about 1500 RPMs.

[0037] It must be noted that the limit values of the engine rotation speed, indicated by Llrpm and L2rpm, should not be considered absolute but should vary depending on the particular characteristics of each engine 2, such as number of cylinders and volume of each cylinder, presence of blowers, turbochargers, superchargers and similar devices to increase the supply of fresh air to the engine intake and the like. Furthermore, when determining the rotation speed limit values Llrpm and L2rpm, the torque corresponding to each of these rotation speed limit values must also be considered.

[0038] The logical loop of steps S50-S70 continues until the logical comparator of step S60 indicates a sequence of negative responses, which are counted by a counter C (step S80). As long as the sum of negative responses from the comparator in step S50 does not exceed a reference value V, pre-programmed and stored in counter C, the electronic control unit (ECU) continues operating according to the first limitation (step S40) at the maximum engine speeds (Llrpm), and counting the number of sequentially negative check loops as reported by the logic comparator. In other words, a sequence of negative responses from the logical comparator indicates that the vehicle is traveling through a flooded region, but without the mass of water reaching or interfering with the intake of fresh air, pointing to an alert situation (Llrpm), but not critical situation (L2rpm).

[0039] Once counter C counts a sequence of negative indications, the routine is diverted again to step S10, in which the signal from the WS sensor (S10) is captured again, right after the electronic control unit (ECU) eliminates the rpm control of the engine 2. Considering that each S40-S60 control loop requires a certain processing time, the quantity of V of negative loops must be understood as the non-occurrence of the presence of water close to or specifically interfering with the admission of fresh air by the engine, in a given period of time (time = V * nr loops S40-S60). On the other hand, and considering that no type of regularity can be defined in flooded regions, especially in urban centers, the inventive system remains activated and detects any new indication of the presence of water, by the WS sensor.

[0040] As can be appreciated by technicians in the sector, the system and method of the invention allow effective and much more precise control of possibility of hydraulic lock in conventional vehicles (i.e. not off-road) when in transit through urban centers during floodings, inundations and the like. Moreover, the inventive system can also be used in off-road vehicles.

[0041] The great difference of the present invention is the engine rotations control and not the vehicle speed, as previously known in the art. This type of control proved to be much more effective in practice, especially considering ordinary drivers who are less qualified than off-road drivers to use safety procedures for crossing rivers and lakes as well as using appropriate equipment for this kind of sport.

[0042] Although the system basically uses the native hardware originally embedded in vehicle 1, only including a WS sensor in the form of an inductive sensor, it is clear to technicians in the sector that the inductive sensor can be replaced by other sensors, such as the parking sensor, in the case of vehicles with this type of assistance feature, among others of those mentioned above in the state of art.

Claims

1. Method of managing an internal combustion engine (2) of a vehicle (1) in transit through a flooded region, said vehicle (1) comprising an engine control unit (ECU), a butterfly valve (3) capable of controlling the admission of a flow of fresh air, a pressure sensor (PS) adjacent to the butterfly valve (3) and an air filter housing (4) provided with an inlet (5) through which the fresh air drawn in is filtered and directed to the butterfly valve (3), whereas the method comprises the steps of:

- to activate the pressure sensor (PS),

- to compare the instantaneous pressures (PSi) measured by the pressure sensor (PS) with an average pressure value (PSm), with the average pressure value (PSm) being calculated by the engine control unit (ECU) using an arithmetic average between the pressure readings previously recorded,

- to identify a negative pressure peak of an instantaneous pressure (PSi) in relation to the mean pressure value (PSm), and

- to define a second limit (L2rpm) of engine (2) rotation speed by the engine control unit (ECU), and the rotational speed of the engine (2) remains limited to the second limit (L2rpm) of rotational speed as long as the instantaneous pressure (PSi) is lower than the average pressure value (PSm).

2. Method, according to claim 1, whereas the step of activating the pressure sensor (PS) comprises:

- to detect the signal from a sensor (WS), indicating water contact with the sensor (WS),

- to identify a positive consistency of the sensor signal (WS) as a function of time, and

- to define a first limit (Llrpm) of engine (2) rotation speed by the engine control unit (ECU) the engine (2) rotation speed remains limited to the first limit (Llrpm) of rotational speed as long as the positive consistency of the sensor signal (WS) remains as a function of time.

3. Method, according to claim 2, whereas the step of identifying a positive consistency comprises, during a determined period of measurement time:

- to store the time (Tw) during which the sensor signal (WS) indicates physical contact with water and the time (Tnw) during which the sensor (WS) does not emit a physical contact signal with water,

- to compare times (Tw) and (Tnw), and - to define the positive consistency of the sensor signal (WS) when the time (Tw) of contact with water is greater than the time (Tnw) of non-contact with water.

4. Method according to any of the preceding claims, whereas the second limit (L2rpm) of engine (2) rotation speed is lower than the first limit (Llrpm) of engine (2) rotation speed and, preferably, the first limit (Llrpm) is 1500 RPMs and the second limit (L2rpm) is 2000 RPMs.

5. Water level sensor system for implementing a method of managing an internal combustion engine (2), as defined in claim 1, for a vehicle (1) when in transit through a flooded region, said vehicle (1) comprising an engine (2) controlled by an engine control unit (ECU), a butterfly valve (3) capable of controlling the intake of flow of fresh air, a pressure sensor (PS) adjacent to the butterfly valve (3) and an air filter housing (4) provided with an inlet (5) through which the fresh air drawn in is filtered and directed to the butterfly valve (3), whereas the system comprise a sensor (WS) capable of defining an alert level of the water depth of the flooded region in relation to the inlet (5) of the air filter housing (4) and capable of disabling the water depth alert level once contact of the water with the sensor (WS); and a pressure sensor (PS) arranged adjacent to the butterfly valve (3) and able to define a critical level of the water depth in relation to the inlet (5) of the air filter housing (4) as long as previously enabled by the sensor (WS).

6. System, according to claim 5, whereas the sensor (WS) is an inductive sensor.

7. System, according to claim 5, whereas the sensor (WS) is a parking sensor.