FR3078742A1 - ELECTRIC DETECTION OF THE CONNECTION OF A FLUID HEATING DEVICE FOR AN INTERNAL COMBUSTION THERMAL MOTOR - Google Patents

Abstract

Apparatus (10) for heating a fluid and for connecting an air intake nozzle (12) to a gas leakage pipe of an internal combustion engine, the device comprising: - a body ( 16) insulated by a thermally conductive tube (18) which defines an internal fluid circulation passage, - electrical means (32) for heating the tube housed in said body, - at least one electrical plug (36) for electrical connection device to a power source, characterized in that it comprises: - means (37, 48) for detecting a correct position of engagement of said tip in said body and / or on said tube, these means detecting circuit comprising an electrical switch (37) having a movable element (37a) configured to cooperate directly or indirectly with said tip, said switch being connected in series with said heating means in a loop (50) extending between terminals (3 6a, 36b) of said electrical plug, and - at least one electrical component (48) having a predetermined impedance value, which is connected in parallel with said loop between the terminals of the electric plug.

Description

Electrical detection of the connection of a fluid heating device for an internal combustion engine

TECHNICAL AREA

The present invention relates in particular to a device for heating a fluid and for connecting an air intake nozzle to a gas leak pipe from an internal combustion engine, in particular for a motor vehicle.

STATE OF THE ART

A gas leakage pipe from an internal combustion engine, for the passage of gases from the combustion chamber to the engine casing, is widely known under the English name "blow-by". In general, the fast connectors of motor vehicles have the function of connecting the fluid transfer pipes to the engine components. In particular, fluid reheating devices are used in pollution control systems in which the gaseous residues of engine combustion which are accumulated in the crankcase and which in particular contain are reinjected into the air intake pipe. some water. In very cold weather, this water can frost and lead to blockage of the hose, which can cause, in the event of total obstruction, an increase in the pressure in the crankcase, leading to the evacuation of the lubricating oil contained in the crankcase. the measurement gauge sockets. This can cause serious damage to the engine.

In the current technique, a reheating device comprises means for heating the fluid based on components with a positive temperature coefficient or "PTC" (or "PTC", acronym for English Positive Temperature Coefficient). The fluid to be heated circulates in a thermally conductive tube, typically aluminum, which is heated by the PTC components. Indeed, a PTC component is relatively small (diameter of approximately 8 mm), which leads to the use of a conductive tube to artificially increase the exchange surface between the fluid and the heating means. There are several ways to thermally connect a PTC component to the tube, generally by welding or by pressing the component on this tube.

The document FR-A1-2 943 718 describes a fluid heating device with PTC components.

Pollution control systems for motor vehicles are subject to strict regulations (OBD standard, acronym for On Board Diagnostic) which was initially implemented by CARB (Californian Air Resources Board) to control polluting emissions from vehicles. . The arrival of electronic engine management computers and associated sensors has enabled vehicles to reduce their polluting emissions. The OBD, as such, stipulates that the vehicle must, throughout its lifetime, continuously monitor the proper functioning of the engine. It specifies that faults on emissions must be indicated by an indicator on the dashboard and that codes corresponding to the faults detected must be recorded by the vehicle. In this context, it is important to ensure the correct connection of the fluid heating device. During an engine maintenance operation requiring the disassembly of the heating device, it is possible that the device is not correctly connected by an operator and this connection fault must be able to be identified and corrected.

The present invention provides an improvement to the technology which makes it possible to meet the needs of the regulations in force.

STATEMENT OF THE INVENTION

According to a first aspect, the invention relates to a device for heating a fluid and for connecting an air intake nozzle to a gas leak pipe from an internal combustion engine, the device comprising:

- an insulating body crossed by a thermally conductive tube which defines an internal passage for circulation of the fluid,

- electrical means for heating the tube housed in said body,

- elastic snap-fastening means carried by said body and configured to cooperate with an external annular rib of said end piece when it is engaged on said tube and / or in said body, and

- At least one electrical plug for the electrical connection of the device to an electrical power source, characterized in that it comprises means for detecting the elastic snap-fitting of said endpiece into said body, these detection means comprising an electric switch, a movable element is actuated by direct cooperation or by means of an intermediate piece with said rib of said tip.

In the current technique, an air intake nozzle comprises an external annular rib intended to cooperate by elastic snap-fastening with a heating device. The invention proposes to detect this latching without modifying the end-piece, which is economical and therefore advantageous. For this, the invention proposes that the detection means cooperate directly or indirectly with the rib of the end piece. In the case of direct cooperation, the mobile element of the electric switch cooperates directly with the rib, in particular by support. In the case of indirect cooperation, an intermediate piece, preferably unique, ensures cooperation between the mobile element of the switch and the rib, preferably by respective supports on the mobile element and the rib.

In the present application, the term "insulator" means a material or a piece that is thermally and / or electrically insulating.

The device according to the invention has a double connection function, fluidic and electrical respectively.

The device according to the invention may include one or more of the following characteristics, taken in isolation from one another or in combination with each other:

- said element is movable along an axis X substantially parallel to an axis Y of revolution or of elongation of said tube,

said intermediate piece is a pivoting blade which is able to bear on said movable element with a view to its movement, and of which a first end is free and intended to cooperate by pressing with said rib,

- said blade is articulated on said switch or close to it by a second opposite end, around an axis Z substantially perpendicular to a plane passing through the axes X and Y,

- said blade has an elongated shape extending in a direction substantially radial with respect to said axis X,

- said body comprises around the tube a cylindrical shoulder for supporting said rib,

said cylindrical shoulder has an internal diameter which is substantially equal to the minimum radial distance between said blade and said axis X,

- the locking means are carried by a ring mounted around a cylindrical portion of said body, the ring being able to be deformed to increase its internal diameter,

the ring is for example split,

- said ring comprises teeth oriented radially inwards and intended to cooperate by elastic snap-fitting with said rib,

said teeth have an internal diameter which is substantially equal to the internal diameter of said shoulder,

- the switch, the heating means and the electrical plug each comprise two electrical terminals, and in which

a first terminal of the plug is connected to a first terminal of said heating means,

- a second terminal of the plug is connected to a first terminal of the switch, and

- a second terminal of the switch is connected to a second terminal of the heating means,

- the first and second terminals of the heating means are connected together by at least one electrical component, such as a resistor, having a predetermined impedance value.

According to a second aspect, the invention relates to a device for heating a fluid and for connecting an air intake nozzle to a gas leak pipe from an internal combustion engine, the device comprising:

- an insulating body crossed by a thermally conductive tube which defines an internal passage for circulation of the fluid,

- electrical means for heating the tube housed in said body,

- at least one electrical plug for electrical connection of the device to an electrical power source, characterized in that it comprises:

- Means for detecting a correct position for engaging said tip in said body and / or on said tube, these detection means comprising an electrical switch, a movable element of which is configured to cooperate directly or indirectly with said tip, said switch being mounted in series with said heating means in a loop extending between terminals of said electrical plug, and

- at least one electrical component having a predetermined impedance value, which is mounted in parallel with said loop between the terminals of the electrical plug.

The device is thus configured so as to facilitate the detection of a correct positioning of the endpiece in the body. It is understood that the device comprises an electrical circuit equivalent to two lines or loops in parallel mounted at the terminals of the electrical plug. A first loop comprises in series the switch and the heating means, and the second loop comprises a predetermined impedance. In the absence of an electrical connection from the plug to the electrical source, this circuit is open and an infinite impedance could therefore be detected in this circuit. When the plug is connected to the electrical source, the impedance value of the circuit depends on the open or closed state of the switch. Furthermore, the resistance or the impedance of the component is advantageously greater than that of the heating means. If the switch is open, the first loop is open and only the second closed loop is conducting. We could then measure an impedance in the circuit which would be substantially equal to the impedance of this second loop. In the case where the switch is closed, the first loop is closed and conducting, which would allow the current to pass preferentially through the first loop, and would make it possible to measure an impedance in the circuit which would be zero or less than the impedance of the second loop.

The device according to the invention may include one or more of the following characteristics, taken in isolation from one another or in combination with each other:

- said component has an impedance value of between 500 and 5000 ohms, and preferably between 1000 and 2000 ohms,

said heating means are of the PTC type,

- said heating means have a lower impedance value than that of said electrical component, and

- Said heating means have an impedance value of less than 100 ohms, preferably less than or equal to 50 ohms, and more preferably less than or equal to 20 ohms.

The invention also relates to a circuit for reheating a fluid for an internal combustion engine, comprising a device as described above and a controller configured to detect one or more of the following states:

- a first state in which the plug of the device is not connected to the power supply, and for which the controller detects an infinite impedance between the terminals of the plug,

- a second state in which the device plug is connected to the electrical power source, and for which the controller detects an impedance whose value corresponds to the impedance value of the electrical component,

- a third state in which the device plug is connected to the electrical power source, and for which the controller detects an impedance substantially zero or less than the impedance value of the electrical component.

The invention also relates to a method of heating a fluid for an internal combustion engine, by means of a circuit as described above, in which it comprises the detection of one or more of said states.

The tube heating means can be activated when the third state is detected.

DESCRIPTION OF THE FIGURES

The invention will be better understood and other details, characteristics and advantages of the invention will appear more clearly on reading the following description given by way of non-limiting example and with reference to the accompanying drawings in which:

FIG. 1 is a schematic perspective view of a heating device according to an embodiment of the invention,

FIG. 2 is an exploded schematic view of the device of FIG. 1,

FIG. 3 is a schematic front view of the device in FIG. 1,

FIG. 4 is a schematic view in axial section of the device of FIG. 1,

FIG. 5 is a view on a larger scale of part of FIG. 4 and illustrates a switch in the open position,

FIG. 6 is a view on a larger scale of part of FIG. 4 and illustrates a switch in the closed position,

FIG. 7 is a partial schematic view on a larger scale of parts of the device in FIG. 1,

FIGS. 8 to 10 are schematic perspective views of electrical connectors of the device in FIG. 1,

FIGS. 11 to 13 are simplified diagrams illustrating an electrical circuit of a device according to the invention,

- Figure 14 is a schematic perspective view of a nozzle,

FIG. 15 is a schematic perspective view of PTC component heating means of a device according to the invention,

FIG. 16 is a schematic cross-sectional view of a device showing the heating means of FIG. 15, and

- Figure 17 is a schematic side view of a device according to an alternative embodiment of the invention.

DETAILED DESCRIPTION

Figures 1 to 10 illustrate an embodiment of a device 10 according to the invention for heating a fluid and connecting a nozzle 12 for air intake to a pipe 14 for gas leakage from a internal combustion engine.

The end piece 12 is schematically represented in dashed lines in FIG. 1 and in more detail in FIG. 14.

The device 10 comprises an insulating body 16 crossed by a thermally conductive tube 18 which defines an internal passage for the circulation of a fluid, preferably in the direction of the arrow in FIG. 1.

The body 16 is for example made of plastic. It can be obtained by injection molding. The body 16 is crossed by the tube 18 which comprises a section 18a covered by the body 16 and a free section 18b and on which the end piece 12 is intended to be engaged.

The tube 18 has a generally cylindrical shape and can be split longitudinally. X denotes its longitudinal or revolution axis, which corresponds to the axis of flow of the fluid in the tube and therefore in the device 10. The section 18a is surrounded by a substantially cylindrical portion 16a of the body 16 which includes an extension 16b, here rear, along the axis X, which has in section a shape of fir or the like in order to retain the pipe 14 intended to be mounted on this extension 16b. The portion 16a is connected on the side of the section 18b to a portion 16c of larger diameter and which extends at a radial distance from the tube 18 in order to define an annular space E for insertion of an end portion of the end piece 12.

The end piece 12 has a generally cylindrical shape which comprises an external cylindrical surface 12a, being at least one external annular rib 12b, the cylindrical surface 12a extending axially between the rib 12b and the free end of the end piece.

As can be seen in FIG. 2, an O-ring seal 26 can be mounted in space E and carried by the portion 16c. This seal 26 is intended to cooperate with the cylindrical surface 12a of the end piece during the engagement of the end piece in the body and in space E (FIGS. 5 and 6), in order to guarantee sealing of the connection.

A ring 28 can also be mounted in space E in order to facilitate centering of the end piece 12 in the body. This ring 28 comprises an internal cylindrical shoulder 28a on which the rib 12b is capable of coming to bear axially. The seal 26 can be interposed axially between the ring 28 and an internal cylindrical shoulder 16d of the body in order to keep it in position. Alternatively, the ring 28 could be formed in one piece with the body, and the seal could be housed in an internal annular groove of the body and in particular of its portion 16c.

The portion 16c of the body is surrounded by an elastic locking ring 30, which is here removable. This ring is of the split type and is elastically deformable so as to increase its internal diameter. The ring comprises teeth 30a oriented radially inwards (relative to the axis X) and able to cooperate by elastic snap-fastening with the rib 12b of the end piece. The teeth 30a are here two in number and diametrically opposite. The circumferential ends of the ring 30, located on either side of its slot, are connected to lugs 30b which can be manipulated by an operator to manually force the spacing of the teeth 30a from each other and increasing the internal diameter of the ring. As seen in FIG. 3, the teeth 30a have their radially internal ends which are situated on a circumference centered on the axis X and having a diameter denoted D. This diameter D is here similar to the internal diameter of the shoulder 28a of the ring 28.

The body 16 also includes a protrusion 16e which extends in a radial direction relative to the axis X, at the level of the portion 16a. This protuberance 16e is hollow and defines an internal housing L for receiving means 32 for heating the tube. These heating means 32 are for example PTC component (s) as described in the previous application cited in the foregoing. An exemplary embodiment of these heating means will be described in the following with reference to FIGS. 15 and 16.

The housing L of the body 16 opens radially outward and is here closed by a cover 34 which is secured to an electrical plug 36 which makes it possible to electrically connect the device 10 to a source of electrical power, via 'an electric cable. This plug 36 extends here in a direction substantially parallel to the axis X and on the side of the extension 16b.

On the side opposite to the plug 36, the cover 34 carries an electrical switch 37, an element 37a of which is movable along an axis Y parallel to the axis X. It can be seen in FIG. 4 that the switch 37 is covered by a cover 38 which is fixed to the cover 34 and / or the body 16. This cover 38 has a general L-shape, a first branch 38a of which extends above the switch 37 and the other branch 38b extends in front of the switch, between the first branch 38a and the portion 16c. The cover and the cover 34 can be fixed to the body by gluing or welding.

The switch 37 is for example of the microswitch type (from the English microswitch). It is here intended to cooperate with the end piece 12, and more particularly with its annular rib 12b. In the example shown, an indirect cooperation between the switch 36 and the rib

12b is made possible by means of an intermediate piece which is here a pivoting blade 40.

The blade 40 has a generally elongated and flat shape in the example shown. It is pivotally mounted at one of its ends, here upper located on the side of the switch 37 (Figures 5 and 6), or in the vicinity of this end (Figure 4), around an axis Z which is substantially perpendicular to the plane passing through the aforementioned axes X and Y, which is the section plane of FIG. 4. The blade 40 has a substantially radial orientation relative to the axis X and its radially internal free end extends as close as possible to the X axis to cooperate with the rib 12b of the nozzle. This end is located at a distance D / 2 from the axis X so that the rib 12b can come to bear axially on the blade 40 and rotate it around the axis Z, during the insertion of the tip 12 in the device.

As can be seen in FIG. 3, the portion 16c and / or the ring 28 may comprise a radial notch 28b for passage of the blade 40. In the case where the ring 28 includes such a notch 28b, it could include latching means intended to cooperate with means complementary to the body 16 so that the notch 28b is correctly positioned around the axis X, with respect to the blade 40. The ring 28 is for example fixed by latching elastic in the body 16.

The branch 38b of the cover 38 extends in front of the blade 40 and protects it, as can be seen in FIG. 3. The radially internal end of the branch 38b comprises a concave rounded peripheral edge (FIG. 3) which is centered on the X axis and whose diameter is greater than the external diameter of the rib 12b so as not to hinder its engagement in the body.

Figures 5 and 6 show the two positions of the movable element 37a of the switch 37. In Figure 5, the blade 40 is in the free state and bears on the element 37a without biasing it. The end piece 12 is engaged in the device 10 but no axial bearing force is exerted by the rib 12b on the blade 40. In FIG. 6, a bearing force has been applied by the rib 12b of the tip 12 on the blade 40, which has pivoted about the Z axis and which has rested on the element 37a and moved it along the Y axis. The radially internal end of the blade 40 is interposed between the shoulder 28a and the rib 12a which bears on this shoulder or is at a short distance from this shoulder. The blade 40 can be moved between the two positions illustrated, over an angular range less than or equal to 10 °.

Figures 7 to 10 show the electrical connection of the switch 37 and the heating means 32, to the plug 36.

The switch 37, the heating means 32 and the electrical plug 36 each comprise at least two electrical terminals. A first terminal 36a of the plug 36 is connected to a first terminal 32a of the heating means 36. A second terminal 36b of the plug 36 is connected to a first terminal 37b of the switch 37. A second terminal 37c of the switch 37 is connected to a second terminal 32b of the heating means 32.

A first electrical conductor 42 shown in FIG. 8 extends between terminals 36b, 37b. A second electrical conductor 44 shown in Figure 9 extends between terminals 36a, 32a and a third electrical conductor 46 shown in Figure 10 extends between terminals 32b, 37c.

Furthermore, a component 48 having a predetermined impedance value, and which is for example a resistor, is connected to the terminals 36a, 36b of the plug 36. The conductors 42-46 as well as the component 48 are here carried by the cover 34 and can be at least partially embedded (by overmolding) in the material of this cover in order to electrically insulate them.

Figures 11 to 13 show in a simplified manner the electrical circuit of the device 10, with the aforementioned references designating the terminals and the various electrical components.

It can be seen in these figures that the switch 37 is mounted in series with the heating means 32 in a loop 50 extending between the terminals 36a, 36b of the plug 36, and that the component 48 is mounted in parallel with the loop 50 between the terminals of plug 36.

These figures show three of the four states that this circuit can adopt.

In a first state shown in Figure 11, the plug 36 of the device 10 is not connected to the power source and is schematically represented by an open switch. In a second state shown in Figure 12, the plug 36 of the device is connected to the power source and is represented by a closed switch. This is also the case in the third state shown in the figure

13. In the second state (FIG. 12), the switch 37 is open, that is to say that the end piece 12 is not fitted into the device and its element 37a is not actuated. In the third state (Figure 13), the switch 37 is closed, that is to say that the end piece 12 is fitted into the device and its element 37a is actuated.

There is a fourth state, not shown, in which the plug 36 is not connected and forms an open switch, while the switch 37 is closed.

Depending on the state of the circuit, the resistor 48 may or may not be conducting, i.e. it may or may not be passing current. In the first and last states, it does not let current flow. In the second state, it lets current flow but not or little in the third state because the current will preferentially flow in the branch of lower impedance.

In the first and last states, due to the non-connection of the plug and therefore of the device to the electrical source, the circuit is completely open and the intensity of the current flowing in this circuit is zero. The equivalent impedance of the circuit is infinite. In the second state, the branch 50 is open and the resistor 48 will allow current to pass between the terminals of the plug. In the third state, the branch is closed and the current will favor a passage in this branch and will supply the heating means 32.

The reference 60 designates a controller or computer associated with this circuit and intended to detect the resistance or impedance value of the circuit to determine on the one hand if the device 10 is correctly connected to the end piece 12 and on the other hand for activate the heating means 32 when this connection is made.

The controller 60 is thus able to identify in what state the circuit is. To do this, it measures the impedance value of the circuit and compares it with one or more predetermined values. When the impedance value is infinite, the circuit is in the first or last state and the device is not operational. When the impedance value is equal to the impedance value of the component 48, which is for example 1.2ΚΩ, the circuit is in the second state, the plug 36 is well connected but the end piece 12 is not not engaged or correctly engaged in the device 10. When the measured impedance value is less than the component 48 impedance value (and is for example a few ohms), or even is zero, the circuit is in the third state , the plug is securely connected and the tip is correctly engaged in the device.

The controller 60 is for example part of the on-board computer of the motor vehicle.

FIGS. 15 and 16 show an exemplary embodiment of the heating means 32 which are mounted in the housing L of the body 16.

The heating means 32 here include a thermistor 62 which is supported on a flat upper face 64a of a block 64 of thermally conductive material (for example aluminum), this block comprising a cylindrical lower face 64b extending around the axis X and surrounding the tube 18 as closely as possible. The block 64 is wedged at the bottom of the housing L, on the side of the tube 18 and the thermistor 62, which is here in the form of a disc, is held on the upper face 64a by intermediate of a helical spring 66 electroconductive mounted constrained between the thermistor and the terminal 32a. Another helical spring 68 electroconductive is mounted constrained between the block 64 and the terminal 32b. The thermistor 62 and the spring 66 are housed in a first cylindrical cavity of a holding member 70 which is mounted in the housing L and which comprises a second cylindrical cavity for holding the spring 68.

FIG. 17 shows an alternative embodiment of the invention in which the device comprises a switch 37 ’whose movable element 37a’ is able to cooperate directly with the rib 12b of the end piece. For this, the switch can be positioned in a direction 10 such that its movable element 37a 'is movable in a direction perpendicular to the axis X of the tube. The switch can be located in the potion 16c of the body and be electrically connected to the electrical plug 36 as described in the above.

The invention therefore makes it possible to detect the physical presence of the end piece 12 in the body of the device 10 in order to diagnose the correct connection of this anti-pollution equipment according to the regulations in force.

Claims (8)

1. A device (10) for reheating a fluid and for connecting a nozzle (12) for admitting air to a gas leak pipe from an internal combustion engine, the device comprising: - an insulating body (16) through which a thermally conductive tube (18) defines an internal passage for circulation of the fluid, - electrical means (32) for heating the tube housed in said body, - at least one electrical plug (36) for electrical connection of the device to an electrical power source, characterized in that it comprises: - Means (37, 48) for detecting a correct position for engaging said tip in said body and / or on said tube, these detection means comprising an electric switch (3, 37 ') including a movable element (37a , 37a ') is configured to cooperate directly or indirectly with said nozzle, said switch being mounted in series with said heating means in a loop (50) extending between terminals (36a, 36b) of said electrical plug, and - at least one electrical component (48) having a predetermined impedance value, which is mounted in parallel with said loop between the terminals of the electrical plug. 2. Device (10) according to the preceding claim, wherein said component (48) has an impedance value of between 500 and 5000 ohms, and preferably between 1000 and 2000 ohms. 3. Device (10) according to claim 1 or 2, wherein said heating means (32) are of the PTC type. 4. Device (10) according to one of the preceding claims, wherein said heating means (32) have a lower impedance value than that of said electrical component (48). 5. Device (10) according to one of the preceding claims, in which said heating means (32) have an impedance value less than 100 ohms, preferably less than or equal to 50 ohms, and more preferably less than or equal to 20 ohms. 6. A circuit for reheating a fluid for an internal combustion engine, comprising a device (10) according to one of the preceding claims and a controller (60) configured to detect one or more of the following states: - a first state in which the plug (36) of the device is not connected to the power supply, and for which the controller (60) detects an infinite impedance between the terminals of the plug, - a second state in which the plug of the device is connected to the electrical power source, and for which the controller detects an impedance whose value corresponds to the impedance value of the electrical component (48), - a third state in which the device plug is connected to the electrical power source, and for which the controller detects an impedance substantially zero or less than the impedance value of the electrical component. 7. A method of reheating a fluid for an internal combustion engine, by means of a circuit according to claim 6, in which it comprises the detection of one or more of said states. 8. The method of claim 7, wherein the heating means (32) of the tube (18) are activated when the third state is detected.