Liquid reservoir for vehicle and motor vehicle system comprising such a reservoir

The present invention relates to a liquid reservoir for a vehicle that is subjected in service to inclinations in at least two different directions, the reservoir comprising a float well which delimits a bowl containing a float that is able to move depending on the level of liquid in the reservoir. The reservoir is characterized in that the float well comprises at least two retention means positioned successively along a flow path of the liquid as far as the bowl, from the outside toward the inside of the float well, each retention means keeping liquid in the float well if the reservoir is inclined in a set of directions specific to this retention means. The invention also relates to a motor vehicle system comprising such a liquid reservoir and means for binary detection of the level of liquid in the reservoir.

RELATED APPLICATIONS

The present application is a National Phase of International Application Number PCT/US2014/015213 filed Feb. 7, 2014, and claims priority to French Application Number 1351100 filed Feb. 8, 2013.

The present invention relates to a liquid reservoir for a vehicle, in particular a motor vehicle. The invention also relates to a motor vehicle system comprising such a reservoir and means for binary detection of the level of liquid in this reservoir. The field of the invention is that of reservoirs provided with devices for detecting the level of liquid.

In practice, the operation of a motor vehicle requires particular fluids such as the coolant, the brake fluid, the engine oil, the power steering oil and the fuel, each being stored in a specific reservoir. The driver of the vehicle has to be informed of the level of certain fluids in the reservoir, for example for safety reasons for the brake fluid or for the purpose of usefulness for the fuel. The inclinations of the vehicle, in dependence on critical driving conditions (acceleration, braking, bends, slopes, etc.) or at a standstill, cause movements of each liquid in the corresponding reservoir.

Existing motor vehicle systems are equipped with various technologies for detecting the level of liquid. In particular, it is known to provide the reservoir with a float, the position of which varies in dependence on the level of liquid in this reservoir, as described for example in DE-A-195 01 210.

The reservoir having a float may be associated with a device for binary detection, which indicates if a minimum level of liquid has or has not been reached, such as for braking or cooling systems, or with a device for continuous detection, such as for the fuel or engine oil.

In the case of binary detection with a float, this detection should be effective regardless of the inclination of the vehicle, not just when the wheels of the vehicle at a standstill are resting on a horizontal flat surface. The position of the float in the reservoir is not always optimal, for example this position may be off-center, given the space requirements imposed by the constructor. When the level of liquid is low, but above the predetermined minimum level for binary detection, some inclinations may cause false detection and an untimely warning to be sent to the driver.

In order to remedy this, it is known to dispose the float in a well provided with an opening. The well conserves a quantity of liquid necessary for keeping the float in position. The opening allows liquid to flow into the well during an inclination of the vehicle in the direction corresponding to this opening. The height of the opening depends in particular on the predetermined minimum level and on the precision of the detection device associated with the float. This solution is satisfactory when a single inclination direction is the cause of untimely detections.

The aim of the invention is to propose a reservoir having an improved float well.

To this end, the subject of the invention is a liquid reservoir for a vehicle that is subjected in service to inclinations in at least two different directions, the reservoir comprising a float well which delimits a bowl containing a float that is able to move depending on the level of liquid in the reservoir. This reservoir is characterized in that the float well comprises at least two retention means positioned successively along a flow path of the liquid as far as the bowl, from the outside toward the inside of the float well, each retention means keeping liquid in the float well if the reservoir is inclined in a set of directions specific to this retention means.

Thus, the invention allows satisfactory detection of the level of liquid in the reservoir, regardless of the inclination of the vehicle and of the reservoir. In particular, when the reservoir is provided with means for binary detection of the level of liquid, untimely detections can be avoided. The level of liquid in the bowl of the float well depends on the level of liquid in the reservoir. When the level of liquid in the reservoir is greater than a predetermined upper reference level, in other words when the volume of liquid in the reservoir is greater than a predetermined upper reference volume, the arrangement of the flow path and of the retention means is such that the bowl is always filled with a sufficient quantity of liquid, regardless of the inclination of the reservoir. When the level of liquid in the reservoir is below a predetermined lower reference level, in other words when the volume of liquid in the reservoir is less than a predetermined lower reference volume, the bowl no longer receives liquid and the position of the float in the bowl makes it possible to detect this situation. A tolerance relative to the detection exists when the volume of liquid in the reservoir is between the upper and lower reference volumes. The invention makes it possible to reduce the range of uncertainty corresponding to this difference in volumes between reference volumes. Advantageously, the invention can be implemented with any type of liquid, reservoir or vehicle.

According to further advantageous features of the invention, taken individually or in combination:Each retention means keeps liquid in the float well if the reservoir is inclined in a set of directions corresponding to a sector defined about a central axis of the float well.The retention means have increasing heights, with respect to a lower wall of the reservoir, along the flow path as far as the bowl.The flow path is generally concentric with a central axis of the float well.The float well comprises a single retention means that forms the inlet to the flow path in the float well, and a single retention means that forms the outlet from the flow path toward the bowl.At least some retention means are generally located on one and the same circle that is concentric with a central axis of the float well.The float well comprises walls that delimit the flow path, of which an inner wall delimits the bowl accommodating the float, the flow path passing around this inner wall as far as the bowl.The float well comprises four retention means distributed at 90 degrees about a central axis of the float well.

Another subject of the invention is a motor vehicle system, characterized in that it comprises a liquid reservoir as mentioned above and means for binary detection of the level of liquid in the reservoir.

According to a particular embodiment, the reservoir contains liquid flowing in a preferred flow, and the first retention means from the outside toward the inside of the float well along the flow path is positioned outside the preferred flow of liquid in the reservoir. Thus, the flow of liquid in the reservoir is calmed and does not disrupt the position of the float in the well. This makes it possible to maintain optimal precision of detection. A reservoir in which the liquid flows in a preferred flow is for example a degassing reservoir with which a coolant system of the engine is equipped.

FIGS. 1 to 6show a reservoir10in accordance with the invention, which contains a liquid L and is suitable for equipping a motor vehicle.

More specifically, the reservoir10is suitable for equipping a motor vehicle system1, also in accordance with the invention, which is shown partially inFIG. 1for the sake of simplification. For example, the reservoir10maybe a brake liquid reservoir with which a motor vehicle braking system is equipped, or a degassing reservoir with which a cooling system for the engine is equipped. The system1comprises pipes or hoses, such as the pipes2and3shown partially and schematically by way of dotted lines inFIG. 1.

In the context of the invention, the system1also comprises means for binary detection of the level of liquid L in the reservoir10, these means not being shown for the sake of simplification.

To this end, the reservoir10comprises a float well20containing a float60which is able to move in dependence on the level of liquid in the float well20, and thus in dependence on the volume of liquid L in the reservoir10, as explained in detail below. The detection of the volume of liquid L in the reservoir10depends on the position of the float60in a bowl22defined in the float well20.

The reservoir10comprises a shell delimiting an internal volume V10. In the example in the figures, the shell of the reservoir10is formed by four side walls11and12, a lower wall13and an upper wall14, all of which are approximately planar. The side walls11and12are opposite one another in pairs and parallel. The walls11have a first length, while the walls12have a second length which is greater than the first length. The mutually parallel walls12may be known as longitudinal walls, while the mutually parallel walls11may be known as transverse walls. The walls11are perpendicular to the walls12. The walls13and14are likewise mutually parallel and perpendicular to the side walls11and12. In other words, the reservoir10has a generally perpendicular horizontal section and a generally parallelepipedal shape.

Alternatively, the reservoir10may have any shape suitable for the present application, for example a generally spherical, ovoid, cubic or any polyhedral shape.

The upper wall14has a neck15provided for filling the reservoir10and the circuit of the system1. One of the side walls12, for example the wall12closest to the neck15, has at least one inlet orifice (not shown for the sake of simplification), which is provided to connect the pipe2to the reservoir10. The lower wall13has at least one outlet orifice (not shown for the sake of simplification), which is provided to connect the pipe3to the reservoir10.

The lower wall13delimits a reference plane P10, which is horizontal when the wheels of the vehicle at rest are resting on a horizontal flat surface. This plane P10thus corresponds to the lowest level of the reservoir10and of the liquid L in the volume V10when the reservoir10is not inclined. In practice, such a reference plane P10is defined regardless of the shape of the reservoir10and the lower wall13. When the vehicle and thus the reservoir10are inclined, the reference plane P10is also inclined, as shown inFIGS. 5 and 6. The actual position of the float60in the bowl22is not shown in theseFIGS. 5 and 6for the sake of simplification.

Regardless of the inclination of the reservoir10, the liquid L in the volume V10is at a substantially horizontal level, without taking the possible oscillations due to the dynamic behavior of this liquid L into account. The behavior of the liquid L in the volume V10also depends on the geometry of the reservoir10and on the flow rate within the system1. When the reservoir10is at rest, the liquid L is at a level NL0parallel to the plane P10. In the example inFIG. 3, this level NL0is identical both in the bowl22and outside the well20. In the case of an insufficient level of liquid in the reservoir10, corresponding to detection and the sending of a warning, this level NL0may be different in the bowl22and outside the well20. When the reservoir10is inclined, the liquid L is at a level NL2in the bowl22and NL1outside the well20, as shown inFIGS. 5 and 6. By virtue of the invention, the bowl22is not emptied if the reservoir10is inclined and the level NL2remains above the level NL1. By contrast, the inclination of the reservoir10in some directions may cause liquid L to flow as far as the bowl22.

As shown in particular inFIGS. 2 and 4, the float well20includes a flow path21of the liquid L as far as the bowl22containing the float60, and also walls24delimiting the path21and the bowl22. The path21guides the flow of liquid L from the outside toward the inside of the well20, as far as the bowl22. The bowl22has a generally cylindrical shape, centered on a central axis X20of the well20. The axis X20is perpendicular to the plane P10. In other words, the axis X20is vertical when the plane P10is horizontal, regardless of the shape of the reservoir10and of the lower wall13. The path21defines a direction of flow about the axis X20. The walls24extend between the lower wall13and the upper wall14of the reservoir10, about the axis X20. The walls24of the well20include a cylindrical outer wall26and a cylindrical inner wall28which are centered on the axis X20, straight parts31,32,33,34,35a,35c,36a,36cperpendicular to the plane P10, and curved parts35band36bthat are concentric with the axis X20. The parts35a,35band35cform a protrusion35which extends beyond the wall26away from the axis X20. Similarly, the parts36a,36band36cform a protrusion36which extends beyond the wall26away from the axis X20.

In the context of the invention, the float well20comprises retention means41,42,43and44which are positioned successively along the flow path21of the liquid L from the outside toward the inside of the well20, as far as the bowl22. The retention means41-44make it possible, firstly, to retain a certain quantity of liquid L in the well20regardless of the inclination of the reservoir10and, secondly, to discharge this liquid L into the bowl22if the reservoir10is inclined. When the volume of liquid L in the reservoir10is greater than a predetermined upper reference volume, the arrangement of the flow path21and of the retention means41-44is such that the bowl22is always filled with a sufficient quantity of liquid L, regardless of the inclination of the reservoir10. When the volume of liquid L in the reservoir10is less than a predetermined lower reference volume, the position of the float60in the bowl22makes it possible to detect this situation and to send a warning. By virtue of the arrangement of the flow path21and of the retention means41-44, the volume tolerance range between the upper and lower reference volumes is reduced.

The retention means41-44are formed on the lower wall13of the reservoir10. A slot, respectively41a,42a,43aand44a, formed in one of the walls24of the well20, on the lower wall13of the reservoir10, corresponds to each retention means41,42,43and44. Each retention means41,42,43and44has a height, respectively H41, H42, H43and H44, which depends on the dimensions of the corresponding slot41a,42a,43aand44a. The heights H41, H42, H43and H44are defined in a direction perpendicular to the lower wall13and to the plane P10. The heights H41, H42, H43and H44are set in dependence on the upper and lower reference volumes. In a preferred but non-obligatory manner, the heights H41, H42, H43and H44increase along the flow path21so as to facilitate the flow of liquid L as far as the bowl22.

Along the path21, the retention means41,42,43and44allow a flow of liquid, respectively F1, F2, F3and F4, to flow in the direction of the bowl22, or in the opposite direction. The retention means41and the slot41aform the only inlet passage for liquid L into the well20, through the walls24, more specifically through the wall26. The retention means44and the slot44aform the only inlet passage for liquid L into the bowl22, through the walls24, more specifically through the wall28. In other words, the retention means41delimits the inlet to the path21, while the retention means44delimits the outlet from the path21. The retention means42is formed in the region of the protrusion35, between the parts32and35aof walls24. The retention means43is formed in the region of the protrusion36, between the parts33and36aof walls24. A cavity51for storing liquid L is formed between the retention means41and42, the straight parts31and32and the walls26and28. A cavity52for storing liquid L is formed between the retention means42and43, the protrusion35, the straight parts32and33and the walls26and28. A cavity53for storing liquid L is formed between the retention means43and44, the protrusion36, the straight parts33and34and the walls and26and28. In other words, the cavities51,52and53are interposed between the retention means41-44.

In the example inFIGS. 2 and 4, the retention means41,42,43and44are located on one and the same circle that is concentric with the axis X20, continuing the wall26. In other words, the retention means41-44are generally formed in an orthoradial orientation with respect to the axis X20, this making it possible to properly control the discharge of liquid L over these retention means41-44. The wall26extends around the axis X20except for, firstly, in the region of the protrusions35and36and, secondly, between the parts31and34. The wall26thus has a generally cylindrical shape, but without forming a complete cylinder around the axis X20. The wall28extends around the axis X20, on a circle that is concentric with this axis X20and has a smaller radius than the circle associated with the wall26. The wall28defines the bowl22, which is closed except for in the region of the retention means44and the slot44a. The wall28thus has a cylindrical shape, and is only open in the region of the slot44a. Alternatively, the walls24, more specifically the wall26and the wall28, may have a different shape. In practice, these walls26and28have a shape which is adapted to the shape of the float60.

In the embodiment inFIGS. 1 to 6, there are four retention means41-44, each corresponding to a set of inclination directions including a critical inclination direction, in an orthogonal reference system. More specifically, as shown inFIGS. 2 and 4 to 6, four orthogonal directions D1, D2, D3and D4which are opposite one another in pairs are defined. The opposite directions D1and D3correspond to the transverse inclinations, while the opposite directions D2and D4correspond to the longitudinal inclinations. When the reservoir10is inclined in one of the directions D1to D4, the axis X20is inclined in this direction D1to D4above the approximately horizontal level NL2of liquid L in the well20. A particular critical detection condition, linked with the functioning of the vehicle, namely in the case of acceleration, braking or turning to the left or right, corresponds to each direction D1to D4.

One of the critical inclination directions, respectively D1, D2, D3and D4, is associated with each retention means41,42,43and44. Furthermore, a sector S1, S2, S3and S4centered on the axis X20is associated with each retention means41,42,43and44, as shown inFIG. 4. Each sector51, S2, S3and S4corresponds to a set of inclination directions, including respectively the directions D1, D2, D3and D4. Each sector S1-S4delimits an angle of 90 degrees about the axis X20. If the reservoir10is inclined in a direction defined by the sector51, the retention means41is then located at the highest point of all the retention means41-44. The same goes for the other sectors S2, S3, S4and the associated retention means, respectively42,43and44.

The detailed operation of the well20, if the reservoir10is inclined, is described in detail below.

When the reservoir10is inclined in the direction D1or any direction defined by the sector S1, a part of the liquid L present outside the well20flows along the flow F1over the retention means41into the cavity51, then along the flow F2over the retention means42into the cavity52, then along the flow F3over the retention means43into the cavity53. A small quantity of liquid L present in the bowl22flows over the retention means44into the cavity53, going back up the path21. The inclination of the reservoir10in the direction D1or a direction defined by the sector51tends to cause an accumulation of liquid L in the cavities52and53and in the region of the protrusion36. When the volume of liquid L in the reservoir10is greater than the upper reference volume, the bowl22conserves a quantity of liquid L that is sufficient to avoid a false warning, whereas when the volume of liquid L in the reservoir10is less than the lower reference volume, the bowl22includes a quantity of liquid L that triggers a warning.

When the reservoir10is inclined in the direction D2or any direction defined by the sector S2, a part of the liquid L present in the cavity51escapes over the retention means41, going back up the path21. A part of the liquid L present in the bowl22flows over the retention means44into the cavity53, going back up the path21. By contrast, a part of the liquid L present in the cavity52flows along the flow F3over the retention means43, as far as into the cavity53. The inclination of the reservoir10in the direction D2or a direction defined by the sector S2tends to cause an accumulation of liquid L in the cavity53and the bowl22. When the volume of liquid L in the reservoir10is greater than the upper reference volume, the bowl22contains a quantity of liquid L that is sufficient to avoid a false warning, whereas when the volume of liquid L in the reservoir10is less than the lower reference volume, the bowl22includes a quantity of liquid L that triggers a warning.

When the reservoir10is inclined in the direction D3or any direction defined by the sector S3, a part of the liquid L present in the cavity52escapes over the retention means42into the cavity51, then over the retention means41and out of the well20, going back up the path21. On the other hand, a part of the liquid L present in the cavity53flows along the flow F4over the retention means44, as far as into the bowl22. The inclination of the reservoir10in the direction D3or in a direction defined by the sector S3tends to cause an accumulation of liquid L in the bowl22. When the volume of liquid L in the reservoir10is greater than the upper reference volume, the bowl22contains a quantity of liquid L that is sufficient to avoid a false warning, whereas when the volume of liquid L in the reservoir10is less than the lower reference volume, the bowl22includes a quantity of liquid L that triggers a warning.

When the reservoir10is inclined in the direction D4or any direction defined by the sector S4, a part of the liquid L present in the cavity53escapes over the retention means43as far as into the cavity52, going back up the path21. A part of the liquid L present in the cavity51escapes over the retention means42as far as into the cavity52. On the other hand, the liquid L present in the bowl22cannot escape over the retention means44. The inclination of the reservoir10in the direction D4or a direction defined by the sector S4tends, firstly, to cause an accumulation of liquid L in the cavities51and52and in the region of the protrusion35and, secondly, to cause liquid L to be kept in the bowl22. When the volume of liquid L in the reservoir10is greater than the upper reference volume, the bowl22conserves a quantity of liquid L that is sufficient to avoid a false warning, whereas when the volume of liquid L in the reservoir10is less than the lower reference volume, the bowl22includes a quantity of liquid L that triggers a warning.

In practice, each retention means41-44keeps liquid Lin the well20or discharges liquid L into the well20, if the reservoir10is inclined in a set of directions specific to this retention means41,42,43or44, for which this retention means41,42,43or44is located at the highest point of all the retention means41-44. Each retention means41-44with which the well20of the reservoir10according to the invention is equipped corresponds to a set of inclination directions which would be liable to generate an untimely detection in the reservoirs of the prior art. Moreover, the heights H41, H42, H43and H44are provided in order that the different possible inclinations of the reservoir10do not cause the discharge into the bowl22or the escape from the bowl22of a quantity of liquid L that is liable to result in false detection depending on the position of the float60. Thus, the invention makes it possible to avoid any untimely detection.

Furthermore, the motor vehicle system1and the reservoir10may be shaped differently thanFIGS. 1 to 6without departing from the scope of the invention. In particular, the shell of the reservoir10, the float well20and the retention means41-44may have any arrangement or configuration suitable for the present application.

Regardless of the embodiment, the float well20comprises at least two retention means positioned successively along the flow path21of the liquid L as far as the bowl22, from the outside toward the inside of the well20, each retention means keeping liquid L in the float well20if the reservoir10is inclined in a set of distinct directions, specific to each retention means. For this set of inclination directions, the retention means becomes the highest point of all the retention means.

Preferably, the float well20comprises between two and four retention means arranged along the flow path21. Alternatively, the well20may have more than four retention means.

In a variant which is not shown, the retention means41-44may be disposed successively along the path21in an orientation different thanFIGS. 1 to 6. For example, the retention means41-44may be disposed in a generally radial orientation with respect to the axis X20.

According to another variant which is not shown, the flow path21may have any shape, as long as the arrangement of the retention means41-44on this path21makes it possible to keep liquid L in the well20or to discharge liquid L into the well20.

According to another variant which is not shown, the walls24do not extend as far as the upper wall14of the reservoir10.

According to another variant which is not shown, the reservoir10may have a general shape other than a parallelepipedal shape, for example a generally spherical shape, cubic shape or any shape.

According to another variant which is not shown, the reservoir10may have further inlet and outlet orifices for liquid, depending on the motor vehicle system1in which this reservoir10is integrated.

According to another variant which is not shown, the reservoir10may include barriers for guiding the flow of liquid L in the volume V10, in particular with respect to the well20and/or with respect to the inlet and outlet orifices for liquid L.

FIGS. 7 and 8show variants of float wells, respectively120and220, suitable for equipping the reservoir10according to the invention.

Some constituent elements of the wells120and220are identical to those in the first embodiment, described above, and have the same reference numerals. Further constituent elements have a similar function, but a different structure or arrangement than the first embodiment described above, and have reference numerals increased by 100. Only the differences from the well20of the first embodiment are described in detail below.

As shown inFIG. 7, the well120comprises a flow path121, walls124, the retention means41and a retention means142. The walls124comprise the wall31, a wall132, and walls126and128. The retention means142is formed in the wall128and forms the outlet of the flow path121toward the bowl22. The two retention means41and142follow one another along the path121. The two retention means41and142are distributed angularly about the central axis X20of the float well120, being generally spaced apart by 90 degrees along the flow path121. Each sector51and S2delimits an angle of 180 degrees about the axis X20. The sector51includes the two critical detection directions D1and D4, while the sector S2includes the two critical detection directions D2and D3.

As an alternative, the two retention means41and142may be spaced apart by an angle other than 90 degrees about the central axis X20. In this case, each sector S1and S2delimits a different angle about the axis X20.

Although less advantageous than the configuration of the well20inFIGS. 1 to 6, the particular configuration of the well120inFIG. 7is simpler and makes it possible to achieve the aim of the invention.

As shown inFIG. 8, the well220comprises a flow path221, walls224, the retention means41, a retention means242and a retention means243. The walls224comprise the wall28, the wall31, the wall34, a wall226and a protrusion235. The three retention means41,242and243follow one another along the path221, with the retention means242being formed in the region of the protrusion235, while the retention means243equivalent to the retention means44is formed in the wall28and forms the outlet of the flow path221toward the bowl22. The three retention means41,242and243are distributed angularly about the central axis X20of the float well220, being generally spaced apart by 135 degrees along the flow path221. Each sector S1and S3delimits an angle of 112.5 degrees, while the sector S2delimits an angle of 135 degrees, about the axis X20. The sector S1includes the critical detection direction D1, the sector S2includes the two critical detection directions D2and D3, while the sector S3includes the critical detection direction D4. The retention means242positioned in the region of the protrusion235thus corresponds to the two critical detection directions D2and D3.

As an alternative, the retention means41,242and243may be spaced apart along the flow path221at different angles, defined about the central axis X20.

In order that each retention means is predominant for a set of quite distinct inclination directions, the retention means may advantageously be distributed angularly about the central axis X20of the float well20, being spaced apart at angles greater than or equal to 90 degrees along the flow path.

Moreover, all or some of the technical features of the various embodiments may be combined with one another. Thus, the reservoir may be adapted in terms of structure, function, cost and performance.