FR3133648A1 - Method for generating functional cooling circuit architectures - Google Patents

Abstract

Title: Method for generating functional cooling circuit architectures Method for generating functional cooling circuit architectures from a list of primary components, comprising: .generation of a set of hydraulic skeletons: - definition of at least one condition for excluding a hydraulic skeleton making it possible to identify hydraulic skeletons to be excluded from all the solutions; - generation of a set of hydraulic skeletons by the construction of a tree representing the set of hydraulic skeleton from a number of connections to be made, the tree comprising vertices representing hydraulic connection points and edges representing fluid branches between two hydraulic connection points; - exclusion of hydraulic skeletons identified as hydraulic skeletons to be excluded, generation of the set of functional architectures of cooling circuits, generation of the set of functional architectures of cooling circuits comprising the following sub-steps: - for each hydraulic skeleton of the set of hydraulic skeletons, generating a set of functional architectures by placing the primary components on fluid branches of the hydraulic skeleton.

Description

Method for generating functional cooling circuit architectures

GENERAL TECHNICAL AREA

The present invention relates to the field of generative design, and more precisely to the development of architectures of cooling circuits of a powertrain of a motor vehicle.

STATE OF THE ART

In order to reduce emissions of pollutants from vehicles (notably CO ₂ and fine particles), it is necessary to optimize engine cooling circuits as best as possible. Indeed, the purpose of the cooling system is to regulate and limit the temperature of a cooling fluid in order to optimize energy consumption and ensure the reliability of the components. The cooling system captures calories through a heat transfer fluid, and transports them to a radiator in order to evacuate them and/or several components requiring calories (for example the cabin heating system or for heating the battery).

Furthermore, the development of hybrid engines has drastically increased the needs in terms of component cooling, with more and more components to be cooled, and their sensitivity to different higher temperatures. The definition of a functional cooling circuit architecture is therefore a crucial step in the development of a new powertrain.

By functional architecture of a cooling circuit, we mean an overall diagram with different branches in which a cooling fluid circulates, and on which components of the cooling circuit are placed such as radiators, pumps, valves, components to be cooled. etc.

Current methods are mainly based on the optimization and hydraulic sizing of already known architectures. However, it has been noted that architectural changes (see for example Torregrosa, AJ, Broatch, A., Olmeda, P., & Romero, C. (2008). Assessment of the influence of different cooling system configurations on engine warm -up, emissions and fuel consumption. International Journal of Automotive Technology, 9(4), 447-458. ) made it possible to greatly reduce the time required for the temperature rise of an internal combustion engine, and therefore to reduce consumption and emissions from said engine. It therefore appears that it would be advantageous to explore the use of new functional cooling circuit architectures in order to meet the needs for energy efficiency and reliability of powertrains.

Furthermore, the available tools dedicated to hydraulic optimization, that is to say the calculation of the sizing of all the components of a hydraulic circuit, do not allow the effective treatment of a large number of functional architectures. . Indeed, the functional architectures being until now developed individually, their modeling into an optimization problem to be solved by an optimization algorithm (in English "solver") is done manually by the designers of the hydraulic circuit, and is not therefore not suitable for processing a large number of functional architectures.

The Applicant, however, realized that to date there was no method allowing an exhaustive study of all possible functional cooling circuit architectures based on a specification of needs in terms of cooling of the different components of the cooling system. a powertrain.

PRESENTATION OF THE INVENTION

An objective of the invention is therefore to allow a systematic study of the possible cooling architectures of a given powertrain based on a specification of the needs in terms of cooling.

For this, according to a first aspect, the present invention proposes a method for generating functional cooling circuit architectures from a list of primary components, the method comprising the following steps:

• generation of a set of hydraulic skeletons (E1) consisting of branches of fluid between hydraulic connection points, the generation of the set of hydraulic skeletons comprising the following sub-steps:
  • definition of at least one exclusion condition (E1.1) of a hydraulic skeleton from the set of hydraulic skeletons, the exclusion condition making it possible to identify hydraulic skeletons to be excluded from the set of solutions;
  • generation of a set of hydraulic skeletons by the construction of a tree (E1.2) representing the set of hydraulic skeleton from a number of connections to be made, the tree comprising vertices representing hydraulic connection points and edges representing branches of fluid between two hydraulic connection points;
  • exclusion (E1.3) from the set of hydraulic skeletons of the hydraulic skeletons identified as hydraulic skeletons to be excluded by at least one exclusion condition,
• generation of the set of functional architectures of cooling circuits (E2), the generation of the set of functional architectures of cooling circuits comprising the following sub-steps:
  • for each hydraulic skeleton of the set of hydraulic skeletons, generation of a set of functional architectures by placing the primary components (E2.1) on fluid branches of the hydraulic skeleton.

The invention is advantageously supplemented by the following characteristics, taken alone or in any of their technically possible combinations:

• the construction of the shaft representing the hydraulic skeleton assembly includes:
  • selecting a first connection point as a root of the tree;
  • the creation of a number of vertices of the tree equal to the number of connections to be made, each of the vertices being connected to the root by an edge representing a branch of fluid between the hydraulic connection point represented by the vertex and the point of hydraulic connection represented by the root of the tree;
  • for each vertex, called the father vertex, created in the previous step, creation of a number of child vertices of the tree equal to the number of connections to be made, each of the vertices being connected to the father vertex by an edge representing a branch of fluid between the hydraulic connection point represented by the child vertex and the hydraulic connection point represented by the father vertex,

the last step being repeated so that the tree created has a depth equal to the number of connections to be made.

• a hydraulic skeleton is represented by a set of couples consisting of labels corresponding to the fluid branches, a first label of the couple being associated with a first hydraulic connection point, and a second label of the couple being associated with a second hydraulic connection point .
• the at least one condition for excluding a hydraulic skeleton from the set of hydraulic skeletons comprises:
  • the number of fluid branches is strictly greater than the number of primary components and/or,
  • the hydraulic skeleton is composed of at least two parts not connected by a branch and/or,
  • the hydraulic skeleton comprises a dead fluid loop and/or,
  • the hydraulic skeleton is an isomorphism of another hydraulic skeleton of the hydraulic skeleton set.
• the step of generating a set of functional architectures by placing the primary components on fluid branches of the hydraulic skeleton comprises, for each hydraulic skeleton, the construction of a tree representing a subset of functional architectures from the hydraulic skeleton and primary component list.
• the construction of the tree representing a functional architecture subset from the hydraulic skeleton and the list of primary components includes:
  • selecting a first component to place on the hydraulic skeleton;
  • creating a number of vertices of the tree equal to the number of fluid branches of the hydraulic circuit, each vertex representing the placement of the first component to be placed on one of the fluid branches of the hydraulic circuit;
  • for each vertex, called the father vertex, created in the previous step, creation of a number of child vertices of the tree equal to the number of fluid branches of the hydraulic circuit, each child vertex representing the placement of a new component to be place on one of the fluid branches of the hydraulic circuit,

the last step being repeated so that the tree created has a depth equal to the number of primary components to be placed.

• a functional architecture is represented by a list of pairs consisting of a numerical value and a list of primary components, each pair being associated with a branch of the hydraulic skeleton, the numerical value of a pair describing the number of primary components present on the associated branch.
• a step of excluding functional architectures identified as being an isomorphism of another functional architecture from all functional architectures.
• the list of primary components is associated with information on the pairs of primary components identified as not being able to be placed on the same branch, the method further comprising a step of excluding functional architectures in which pairs of primary components, identified as cannot be placed on the same branch, are placed on the same branch of the functional architecture, of all functional architectures.
• the method further comprising a step of hydraulic sizing of the functional architectures generated, the hydraulic sizing comprising the calculation of an optimal distribution of the hydraulic fluid flow in the branches of the hydraulic circuit defined by a functional architecture, and/or the calculation of values optimal permeability of the hydraulic fluid branches, and/or the calculation of the optimal diameter of the pipes of the hydraulic circuit defined by a functional architecture, the calculations being carried out for operating points, an operating point including an engine speed, an engine torque , and a temperature of the cooling fluid.
• the step of hydraulic sizing of the generated functional architectures comprises, for each branch of each generated functional architecture, steps of:
  • generation of a set of state equations associated with the branch of functional architecture, the state functions defining constraints of an optimization problem;
  • for each branch, optimization by an optimization algorithm of the optimization problem defined by all of the constraints generated in the previous step, as well as by an objective function dependent on the total hydraulic power of the circuit.
• the step of hydraulic sizing of the generated functional architectures comprises, for each generated functional architecture, steps of:
  • generation of a set of state equations associated with the functional architecture, the state functions defining constraints of an optimization problem;
  • optimization by an optimization algorithm of the optimization problem defined by all of the constraints generated in the previous step, as well as by an objective function dependent on the total hydraulic power of the circuit.
• the set of state equations associated with the generated functional architecture includes:
  • for each mesh of the hydraulic circuit defined by the hydraulic architecture, an equation defining that the sum of the pressure losses in said mesh is zero, the pressure losses of a component being defined by the permeability of the component associated with a flow rate;
  • for each node of the hydraulic circuit defined by the hydraulic architecture, an equation defining that the sum of the incoming and outgoing flow rates of this node is zero,
    these state equations being used in a first optimization for

each branch of each hydraulic circuit defined by a hydraulic architecture.

• the set of state equations associated with the generated functional architecture includes:
  • for each operating point, the flow rate in each component of a branch must be greater than or equal to a predefined flow rate for the component at said operating point;
  • for each operating point, a maximum permeability associated with each component;
  • for each operating point, a minimum permeability associated with each component

these state equations being used in a second optimization for each hydraulic circuit defined by a hydraulic architecture,

• The optimization algorithm used to solve the optimization problem is the DIRECT algorithm.

According to a second and third aspect, the invention proposes a computer program product comprising code instructions for the execution of a method according to the first aspect of generating functional architecture of a cooling circuit, when said program is executed on a computer; and storage means readable by computer equipment on which is recorded a computer program product comprising code instructions for the execution of a method according to the first aspect of generating a functional architecture of a cooling circuit, when said program is executed on a computer.

PRESENTATION OF FIGURES

Other characteristics and advantages of the present invention will appear on reading the following description of a preferred embodiment. This description will be given with reference to the appended drawings in which:

there represents the steps of a preferred embodiment of the method according to the invention;

there is a diagram of an architecture for implementing the method according to the invention.

DETAILED DESCRIPTION

In reference to the , a method is proposed for generating functional architectures of the cooling circuit of a motor vehicle. To generate functional cooling system architectures, the method takes as input a list of primary components required for powertrain operation, as well as powertrain cooling requirements expressed as cooling flow rate. These primary components are the essential components of a hydraulic circuit, that is to say those for which the hydraulic circuit is developed. These components are components requiring either to be cooled or heated for their proper functioning. Furthermore, the radiators allowing the transfer of calories to the outside of the circuit can also be included in these primary components.

The first step E1 consists of generating a set of hydraulic skeletons, these hydraulic skeletons being represented by graphs comprising nodes and edges, and consisting of a hydraulic circuit not yet comprising hydraulic components (radiators, pumps, etc.). This skeleton must therefore be functional from a hydraulic point of view, that is to say it must allow the circulation of a hydraulic fluid throughout the circuit. Thus the circuit must not include a dead loop, that is to say that there must exist for any pair of connection points of the skeleton at least two different paths between these two points in the graph, moreover, the graph must be connected in the sense of graph theory. In order to allow the automatic processing of the notion of hydraulic skeleton, a representation of the hydraulic skeletons must be defined, each skeleton is therefore represented by a set of pairs made up of labels. These pairs of labels then correspond to the fluid branches of the skeleton, the first label of the couple is associated with a first hydraulic connection point, in other words a first end of the branch, and the second label of the couple being associated with a second point hydraulic connection, here the second end of the branch.

This first step is divided into several sub-steps which will be described below.

The first sub-step E1.1 is a definition of the conditions for excluding a hydraulic skeleton from the set of hydraulic skeletons, these exclusion conditions making it possible to identify hydraulic skeletons to be excluded from the set of solutions continued to their generation. These exclusion conditions may include:

• the case where the number of fluid branches is strictly greater than the number of primary components, that is to say that hydraulic fluid branches of the skeletons would be useless (since there are no components to place on them);
• the case where the hydraulic skeleton is composed of at least two parts not connected by a branch (or two if we directly integrate the condition on dead fluid loops here), quite obviously, such a skeleton will not be functional;
• the case where the hydraulic skeleton includes a dead fluid loop as described previously, the dead loops correspond to the case where there do not exist for any pair of connection points of the skeleton at least two different paths between these two points in the graph, in this case, the skeleton is considered to include a dead loop and therefore the skeleton can be excluded;
• the case where the hydraulic skeleton is an isomorphism of another hydraulic skeleton of the set of hydraulic skeleton for this the known methods for identifying isomorphisms between two graphs can be used.

This step of defining the exclusion conditions can obviously be implemented both at the start of the process and just before the exclusion step itself.

Then, a step E1.2 of generating a set of hydraulic skeletons is implemented. To do this, the method proceeds to the construction of a tree representing the entire hydraulic skeleton from the number of connections to be made in this skeleton. More precisely, this tree representing the entire hydraulic skeleton is made up of vertices and edges, one of the vertices being the root. The vertices (except the root) all represent a connection point of the hydraulic skeleton, so each vertex will have a parent vertex, as well as a number of child vertices equal to the maximum number of possible connection points. A path, from the root to an internal node or a leaf of the tree without ever taking an edge more than once then constitutes a hydraulic skeleton, in the sense that this path represents a set of edges and vertex of a graph that can be used as a hydraulic skeleton. The construction of the tree can be carried out using the following process:

• arbitrary selection of a first connection point, this connection point then becomes the root of the tree;
• creation of a number of vertices of the tree equal to the number of connections to be made, each of the vertices being connected to the root by an edge representing a branch of fluid between the hydraulic connection point represented by the vertex and the connection point hydraulic represented by the root of the tree, this operation makes it possible to represent all the possible connection choices;
• then, for each vertex, called the father vertex, created in the previous step, creation of a number of child vertices of the tree equal to the number of connections to be made, each of the vertices being connected to the father vertex by an edge representing a fluid branch between the hydraulic connection point represented by the child vertex and the hydraulic connection point represented by the father vertex, it will be obvious that this step is similar to the previous one if we consider the father vertex as the root of an under tree;
• this last step can then be repeated as many times as necessary so that the tree created has a depth equal to the number of connections to be made.

It will appear to those skilled in the art that this process described above can be implemented as well in the form of a recursive or iterative program, and will give the same result.

Once the tree is generated, it will then be possible to reduce the number of hydraulic skeletons by excluding the skeletons that do not meet the physical constraints described previously. It is then sufficient to evaluate for each hydraulic skeleton, in other words, for each path from the root not passing twice through an edge, whether or not the hydraulic skeleton respects the exclusion conditions listed previously. In the case where at least one of these conditions is verified, therefore the hydraulic skeleton is not feasible from a physical point of view, the skeleton is then excluded in order not to lead to further treatment, and therefore to reduce the calculation time required.

At the end of the steps previously described, we therefore have a list of hydraulic skeletons that are all physically feasible, and on which all the primary components necessary for the proper functioning of the powertrain can be placed. The set of skeletons thus generated has the advantage of being exhaustive given that it includes all the possible hydraulic skeletons based on the constraint of the number of components to be placed. It is therefore appropriate to then study all possible component placements on each of the skeletons thus generated.

The method therefore includes a step E2 of generating the set of functional architectures of cooling circuits. For this, in a sub-step E2.1, all of the placements of primary components on fluid branches of the hydraulic skeleton are listed from each hydraulic skeleton of the set of hydraulic skeletons obtained from the constructed tree . A method similar to that used for the generation of all possible hydraulic skeletons is therefore used, it involves constructing a tree representing all possible component placements. However, it should be noted here that a tree must be built for each possible hydraulic skeleton; the step of checking the exclusion conditions described above is therefore particularly advantageous in that it makes it possible to greatly reduce the number of trees to be built, and therefore reduce the necessary calculation time. The placement of the components on the hydraulic skeleton is therefore based on a list of primary components obtained previously and dependent on the specifications of the powertrain considered.

The construction of the tree can therefore be carried out in the manner described below:

• selection of a first component to be placed on the hydraulic skeleton, this involves arbitrarily choosing a component from the list of components to be placed and associating it with the root of the tree;
• creation of a number of vertices of the tree equal to the number of fluid branches of the hydraulic circuit, each vertex representing the placement of the first component (associated with the root) on one of the fluid branches of the hydraulic circuit;
• then, starting from each of the previously defined vertices, for each vertex, called the father vertex, created in the previous step, creation of a number of child vertices of the tree equal to the number of fluid branches of the hydraulic circuit, each vertex wires representing the placement of a new component to be placed on one of the fluid branches of the hydraulic circuit. We therefore have at each depth of the tree a component which is placed on a branch of the hydraulic skeleton;
• this last step is then repeated until the tree created has a depth equal to the number of primary components to place.

The tree thus constructed also makes it possible to represent all the functional architectures (i.e. the skeletons on which the primary components are placed). Indeed, a path from the root to a leaf and never passing twice through an edge of the tree corresponds to a placement of all the primary components on the hydraulic skeleton. The functional architectures could be represented by a list (that is to say an ordered set) of pairs, each of these pairs being made up of a numerical value and a list of primary components, thus, each of these pairs will represent the placement of primary components on a branch. The numerical value of the torque then describes the number of primary components on the branch considered.

Similar to the construction of all the hydraulic skeletons, certain functional architectures may be excluded in order to reduce processing times, and to avoid retaining solutions that cannot be physically achieved. We can therefore again check whether the hydraulic architectures are isomorphisms from each other and keep only one. In addition, we can previously define for each component the other components near which it cannot be placed on a branch. For example, if two components generate heat and must be cooled, they cannot be placed one after the other on the same branch of fluid without a means of cooling the fluid between them.

Following the generation of functional architecture, hydraulic optimization of functional architectures can also be carried out. This hydraulic optimization thus makes it possible to calculate the optimal distribution of the flow of hydraulic fluid in the branches of the hydraulic circuit, as well as to define the optimal values of permeability of the branches of hydraulic fluid and the optimal diameter of the pipes of the hydraulic circuit according to points of operation, with the aim of minimizing pressure losses in the hydraulic circuit. The operating points being defined as triplets of values including a desired engine speed, an engine torque, as well as a temperature of the cooling fluid, and come from the approval cycles, for example the WLTC cycle (for Worldwide Harmonized Light Vehicles Test Cycle).

For the optimization of hydraulic circuits, two approaches can be used alone or in combination, the first consists of carrying out, for each functional architecture of the set of functional architectures, an optimization at the level of each branch of the hydraulic circuit defined by functional architecture, we thus obtain a first dimensioning of the components of each branch, the second consists of considering an architecture as a whole in order to achieve an overall optimization of the components throughout the circuit.

For the first approach, the optimization problem is modeled from the application of Kirchhoff's laws (law of meshes and law of nodes) to the meshed hydraulic circuit defined by the functional architecture. The law of meshes specifies that the algebraic sum of the pressure losses of each component placed on a mesh is zero, in other words:

,

With a function defining the pressure loss of a permeability component Se for a flow rate Q.

The law of nodes specifies that for each node of the hydraulic circuit, the sum of the flows entering and leaving the node is zero, in other words:

,

With , the flow rate of branch i among the n incoming and outgoing branches of the node studied.

These laws applied to each mesh and each node of the hydraulic architecture therefore make it possible to obtain a system of equations to be solved by an optimization algorithm, the objective function of the optimization problem being able to be defined as the total hydraulic power of the circuit, the optimization variable being the permeability Se of each of the components of the circuit.

We therefore obtain the following problem to optimize:

With,

with , the hydraulic permeability of the component present on the branch considered,

the total hydraulic power,

For the weighting coefficients,

For the flow rate calculated at the level of the branch considered allowing at least the flow rate specified for the operating point k for each component present on the branch,

the load losses at the branch level for each component present on the branch,

For And , the function representing the constraints relating to compliance with the cooling requirements of the components at the operating point (the flow rate in the index component must have at least the flow on point of operation ),

For And , the function representing the maximum permeability of the component of index j at the operating point ,

For And , the function representing the minimum permeability of the component of index j at the operating point .

This formulation of the optimization problems to be solved can then be carried out automatically from a generated functional architecture, the generated functional architectures completely defining the placement of the different components on the branches of the circuit.

The resolution of these optimization problems can then be done using a suitable solver, for example, a DIRECT algorithm can be used to determine the optimal permeabilities making it possible to minimize the hydraulic power necessary for the circuit on each of the points defined operating conditions. Furthermore, each operating point may be associated with a weighting depending on the frequency of use of the operating point in a standard mode of use of the powertrain. These weightings advantageously prevent the cooling circuit from being sized in order to optimize the hydraulic power on an operating point which is used very little, at the expense of the hydraulic power on other much more operating points. used.

Thus, in order to favor the most used operating points over an approval cycle, the weighting coefficients are defined by barycenter coordinates. This method is applied to a cloud of operating points to calculate the weighting coefficients according to the use of an HEV system on the approval cycle. The temporal evolutions of the state variables characterizing the operating points studied come from the definition of the management law of the hybrid vehicle system over the chosen approval cycle. At each time step of the cycle, the values taken by the different state variables make it possible to position a point in the cloud of operating points. From a Delaunay triangulation, used to generate a mesh, the cloud of operating points is meshed. The mesh obtained makes it possible to select at each time step, the points closest to the point previously positioned in the cloud of operating points. Depending on the dimensions of the point cloud, the necessary number of points to select is defined.

For the second approach, the optimization problem to be solved is therefore global to the functional architecture studied. This time, the optimization is therefore done at the level of the permeability of the branches (and not the components of a branch). The objective here is also to minimize the weighted hydraulic power but this time at the level of the complete circuit. The optimization problem is therefore:

With,

with , the hydraulic permeability of branch l of the hydraulic circuit considered,

the total hydraulic power,

For the weighting coefficient associated with the operating point ,

For the flow calculated at the level of the hydraulic circuit considered allowing at least the flow specified for the operating point for each branch of the circuit,

the pressure losses at the circuit level, for each branch of the hydraulic circuit,

For And , the function representing the constraints relating to compliance with the cooling requirements of the branches at the operating point (the flow in the branch with index l must have at least the flow on point of operation ),

For And , the function representing the maximum permeability of the branch of index l at the operating point ,

For And , the function representing the minimum permeability of the branch of index l at the operating point .

Here too, the optimization problem can be solved by a known solver such as the DIRECT algorithm.

The proposed hydraulic optimization method thus makes it possible to determine the flow distribution in the branches and the hydraulic power in order to respect the constraints on the cooling requirements of the components. For each operating point the hydraulic power weighted by its use is calculated. The optimal permeability values of the branches make it possible to translate, like the optimization of permeabilities at the decomposing level, the need for by-pass or nozzle. Optimal permeability of a branch greater than its initial value reflects the need for a by-pass, the opposite requires a nozzle.

The process thus makes it possible, from a simple specification of the cooling needs of a powertrain and the components to be integrated into the cooling circuit, to obtain and compare all possible cooling circuits. The study is therefore exhaustive and no longer limited to modifications of known architectures. It is therefore possible to create much more efficient cooling circuits and compare them according to numerous criteria.

In reference to the , the method can be implemented by a computer 10, comprising data processing means 11 configured to implement the method for generating functional architectures, as well as storage means 12, such as a computer memory, for example a hard disk on which code instructions are recorded for the execution of the process for generating functional architectures.

Claims (17)

Method for generating functional cooling circuit architectures from a list of primary components, the method comprising the following steps:
.generation of a set of hydraulic skeletons (E1) consisting of fluid branches between hydraulic connection points, the generation of the set of hydraulic skeletons comprising the following sub-steps:
- definition of at least one exclusion condition (E1.1) of a hydraulic skeleton from the set of hydraulic skeletons, the exclusion condition making it possible to identify hydraulic skeletons to be excluded from the set of solutions;
- generation of a set of hydraulic skeletons by the construction of a tree (E1.2) representing the set of hydraulic skeleton from a number of connections to be made, the tree comprising vertices representing connection points hydraulics and edges representing branches of fluid between two hydraulic connection points;
- exclusion (E1.3) from the set of hydraulic skeletons of the hydraulic skeletons identified as hydraulic skeletons to be excluded by at least one exclusion condition,
.generation of the set of functional architectures of cooling circuits (E2), the generation of the set of functional architectures of cooling circuits comprising the following sub-steps:
- for each hydraulic skeleton of the set of hydraulic skeletons, generation of a set of functional architectures by placing the primary components (E2.1) on fluid branches of the hydraulic skeleton. A method according to claim 1, wherein the construction of the shaft representing the hydraulic skeleton assembly comprises:
.the selection of a first connection point as a root of the tree;
.the creation of a number of vertices of the tree equal to the number of connections to be made, each of the vertices being connected to the root by an edge representing a branch of fluid between the hydraulic connection point represented by the vertex and the point hydraulic connection represented by the root of the tree;
.for each vertex, called the father vertex, created in the previous step, creation of a number of child vertices of the tree equal to the number of connections to be made, each of the vertices being connected to the father vertex by an edge representing a branch of fluid between the hydraulic connection point represented by the child vertex and the hydraulic connection point represented by the father vertex,
the last step being repeated so that the tree created has a depth equal to the number of connections to be made. Method according to claim 2, in which a hydraulic skeleton is represented by a set of couples consisting of labels corresponding to the fluid branches, a first label of the couple being associated with a first hydraulic connection point, and a second label of the couple being associated with a second hydraulic connection point. Method according to one of claims 1 to 3, in which the at least one condition for excluding a hydraulic skeleton from the set of hydraulic skeletons comprises:
.the number of fluid branches is strictly greater than the number of primary components and/or,
.the hydraulic skeleton is composed of at least two parts not connected by a branch and/or,
.the hydraulic skeleton includes a dead fluid loop and/or,
.the hydraulic skeleton is an isomorphism of another hydraulic skeleton of the hydraulic skeleton set. Method according to one of claims 1 to 4, in which the step of generating a set of functional architectures by placing the primary components on fluid branches of the hydraulic skeleton comprises for each hydraulic skeleton, the construction of a tree representing a subset of functional architecture from the hydraulic skeleton and the list of primary components. Method according to claim 5, in which the construction of the tree representing a functional architecture subset from the hydraulic skeleton and the list of primary components comprises:
.the selection of a first component to be placed on the hydraulic skeleton;
.the creation of a number of vertices of the tree equal to the number of fluid branches of the hydraulic circuit, each vertex representing the placement of the first component to be placed on one of the fluid branches of the hydraulic circuit;
. for each vertex, called the father vertex, created in the previous step, creation of a number of child vertices of the tree equal to the number of fluid branches of the hydraulic circuit, each child vertex representing the placement of a new component to be place on one of the fluid branches of the hydraulic circuit,
the last step being repeated so that the tree created has a depth equal to the number of primary components to be placed. Method according to claim 6, in which, a functional architecture is represented by a list of pairs consisting of a digital value and a list of primary components, each pair being associated with a branch of the hydraulic skeleton, the digital value of a pair describing the number of primary components present on the associated branch.
Method according to one of claims 5 to 7, further comprising a step of excluding functional architectures identified as being an isomorphism of another functional architecture from all of the functional architectures. Method according to one of claims 5 to 8, in which the list of primary components is associated with information on the primary component pairs identified as not being able to be placed on the same branch, the method further comprising an exclusion step functional architectures in which pairs of primary components, identified as not being able to be placed on the same branch, are placed on the same branch of the functional architecture, of all the functional architectures. Method according to one of claims 1 to 9, further comprising a step of hydraulic sizing of the functional architectures generated, the hydraulic sizing comprising the calculation of an optimal distribution of the flow of hydraulic fluid in the branches of the hydraulic circuit defined by an architecture functional, and/or the calculation of optimal values of permeability of the branches of hydraulic fluid, and/or the calculation of the optimal diameter of the pipes of the hydraulic circuit defined by a functional architecture, the calculations being carried out for operating points, a point of operation including engine speed, engine torque, and cooling fluid temperature. Method according to claim 10, in which the step of hydraulically sizing the generated functional architectures comprises, for each branch of each generated functional architecture, steps of:
- generation of a set of state equations associated with the branch of functional architecture, the state functions defining the constraints of an optimization problem;
- for each branch, optimization by an optimization algorithm of the optimization problem defined by all of the constraints generated in the previous step, as well as by an objective function dependent on the total hydraulic power of the circuit. Method according to claim 10, in which the step of hydraulic sizing of the generated functional architectures comprises, for each generated functional architecture, steps of:
- generation of a set of state equations associated with the functional architecture, the state functions defining constraints of an optimization problem;
- optimization by an optimization algorithm of the optimization problem defined by all of the constraints generated in the previous step, as well as by an objective function dependent on the total hydraulic power of the circuit. Method according to claim 11, in which the set of state equations associated with the generated functional architecture comprises:
- for each mesh of the hydraulic circuit defined by the hydraulic architecture, an equation defining that the sum of the pressure losses in said mesh is zero, the pressure losses of a component being defined by the permeability of the component associated with a flow rate;
- for each node of the hydraulic circuit defined by the hydraulic architecture, an equation defining that the sum of the incoming and outgoing flow rates of this node is zero,
these state equations being used in a first optimization for each branch of each hydraulic circuit defined by a hydraulic architecture. Method according to claim 12, in which the set of state equations associated with the generated functional architecture comprises:
- for each operating point, the flow rate in each component of a branch must be greater than or equal to a predefined flow rate for the component at said operating point;
- for each operating point, a maximum permeability associated with each component;
- for each operating point, a minimum permeability associated with each component
these state equations being used in a second optimization for each hydraulic circuit defined by a hydraulic architecture, Method according to one of claims 12 to 14, in which the optimization algorithm used to solve the optimization problem is the DIRECT algorithm. Computer program product comprising code instructions for executing a method according to one of claims 1 to 15 for generating a functional architecture of a cooling circuit, when said program is executed on a computer. Storage means readable by computer equipment on which is recorded a computer program product comprising code instructions for executing a method according to one of claims 1 to 15 for generating a functional architecture of a cooling circuit , when said program is executed on a computer.