Method for preheating an after-treatment device

Abstract

Disclosed is a preheating method for controlling the rise in temperature of an after-treatment device (100) of a motor vehicle that is driven at least partially by an internal combustion engine, characterised in that the preheating method comprises a step (6) of pre-heating the after-treatment device (100) at a threshold heating power level (22, 44) and at least one cycle (40, 42) following the pre-heating step (6), this cycle (40, 42) comprising a step (7, 8) of detecting a user activity included in a list of key activities representing a desire (103) to start up the vehicle and a step (9, 10) of increasing the heating power level to a higher heating power level when a key activity representing a desire (103) to start up the vehicle is detected.

Description

[0001] The present invention relates to the field of pollution control for vehicles powered at least partially by an internal combustion engine, i.e., for example, a hybrid vehicle or a purely combustion engine vehicle. More particularly, the invention relates to a method for preheating a pollution aftertreatment device for such an engine, configured to control the temperature rise of this aftertreatment device.

[0002] Car manufacturers are seeking to reduce polluting emissions from internal combustion engines, including emissions of unburned hydrocarbons (HC), nitrogen oxides (NOx) and nitrogen monoxide (CO), as well as emissions of carbon dioxide (CO2), which is a greenhouse gas, on their ranges of vehicles that are powered at least in part by such internal combustion engines.

[0003] A known way to reduce emissions of pollutants from these engines' exhaust gases into the atmosphere is to add aftertreatment devices to the vehicle's exhaust system. For example, these systems can be exhaust catalytic converters, which treat the exhaust gases. Three-way catalytic converters, particularly in the case of gasoline engines, oxidize unburned hydrocarbons and carbon monoxide, and reduce nitrogen oxides. Catalytic converters currently used in vehicles require a certain temperature, known as the activation temperature, to reach their maximum capacity—that is, to achieve sufficient efficiency in converting pollutants into more harmless molecules. Generally, the temperature required for a catalytic converter to function properly is around 450°C.

[0004] It is therefore necessary to preheat the after-treatment system on a vehicle to ensure that its activation temperature is reached as soon as possible after the vehicle starts. As is known, manufacturers add electrical devices, such as heating grids, to the catalytic converters to perform this preheating operation. These grids allow the catalytic converter to reach the required temperature.

[0005] The electrical energy used to make the pollution control systems efficient via these preheating methods is drawn from a battery, which naturally has a certain storage capacity.

[0006] As mentioned, it is known to perform a preheating operation to ensure the catalytic converter is effective from the moment the vehicle starts, and it is also known to anticipate this preheating operation so that the user does not have to wait unreasonably before starting their vehicle. The preheating operation is initiated at a specific time, which could be, for example, when the user approaches the vehicle.

[0007] Typically, the user is expected to start the vehicle and its combustion engine immediately after this preheating phase of the after-treatment device. Following this, the battery can be recharged by an alternator or a similar system. This system is known from prior art, notably in documents US5155995A and US11085343B2.

[0008] One drawback of such a system is the risk that the after-treatment device may preheat while the vehicle, at least partially powered by an internal combustion engine, is not subsequently started. This can typically occur when the user follows the standard starting steps (unlocking the vehicle, getting into the driver's seat, etc.) but does not actually start the engine. The battery cannot then be recharged as intended in the typical scenario. Repeatedly performing this scenario will tend to drain a significant amount of battery power, leading to a critical decrease in battery level and, ultimately, a reduction in the preheating capacity.

[0009] The present invention aims to provide a solution to the technical problem described above by proposing a preheating method for a post-processing device that allows the temperature rise to be adapted according to the intended operating mode. Such a method optimizes the preheating of a post-processing device.

[0010] The present invention thus aims at a preheating method intended to control the temperature rise of an after-treatment device of a vehicle powered at least in part by an internal combustion engine, characterized in that the preheating method comprises a preheating start step of the after-treatment device to a threshold heating power level, and at least one cycle following the start step, this cycle comprising a step of detecting a user action included in a list of key actions representative of an intention to start the vehicle, and a step of increasing the heating power level to a higher heating power level when a key action representative of an intention to start the vehicle is detected.

[0011] The launch phase is triggered by the detection of a predefined situation indicating an intention to use the vehicle. This predefined situation can be a interaction between the vehicle and the user, for example, when the user approaches the vehicle and their remote key fob or phone is detected, or when the user places their hand near the door handle. Specific sensors for detecting this predefined situation can be used, or sensors already installed in the vehicle. The predefined situation can also be a specific time, for example, if the launch phase is triggered daily. This specific time can be configured in the system or learned through regular vehicle use, for example, if the vehicle is unlocked every day at a certain time.

[0012] It should be noted that the predefined situation reveals a desire to use the vehicle, i.e. for example a desire or action to enter the vehicle or an action of the user sitting in the driver's seat of the vehicle, but that it is not representative of a desire to start.

[0013] Such an action representing a desire to start is considered according to the invention during a cycle following the launch step, and in which there is at least one step of detection of this action and one step of increasing the temperature of the post-processing device.

[0014] The detection stage implements means capable of detecting one or more key actions listed in a list of key actions representative of an intention to start the vehicle. These key actions, representative of an intention to start, are detected by means capable of detecting one or more user actions related to the vehicle. For example, fastening one's seatbelt could be considered a key action representative of an intention to start the vehicle.

[0015] As mentioned, the increase step allows the heating power level to be raised to an intermediate level, approaching, or reaching, the maximum heating power level.

[0016] The process includes at least one cycle following the start-up step, but it should be noted that it can comprise several successive cycles. The end of the ramp-up step of the first cycle corresponds to the triggering of the detection step of the next cycle. Each of these successive cycles includes an intermediate heating power level, with the intermediate heating power level of a cycle being higher than the heating power level of the previous cycle or the threshold heating power level. The succession of these cycles allows the heating power level to reach the maximum heating power level in successive steps.

[0017] The preheating of the post-processing device is achieved by a thermal system, such as an electric heating grid, which is powered by a battery. It is understood that the maximum heating power level corresponds to an operating mode in which the thermal system provides the maximum thermal energy it is capable of delivering.

[0018] Advantageously, the preheating process implements a start-up step and at least one cycle comprising at least one detection step that takes into account a user action and an increase step. This configuration of the preheating process, with an increase in the thermal power level in successive steps, allows for a better understanding of situations where the user deviates from a conventional vehicle start-up pattern and decides not to start or to delay starting the vehicle while inside the passenger compartment. This avoids maximum energy loss by eliminating the need for a complete preheating of the after-treatment system. Energy losses will be limited to the plateau, or intermediate heating power level, reached by the system.In other words, this gradual increase in heating level allows the system to approach maximum power, making the after-treatment system efficient once the vehicle is started. However, it also allows the user to realize that they will delay or cancel starting the vehicle before the preheating level is reached, thus saving energy consumed by the thermal system. This process slows battery wear and reduces energy consumption, since the alternator will have less energy to supply to the battery at startup. Because the alternator draws the energy needed to recharge the battery from the internal combustion engine, this reduces the engine's fuel consumption and therefore its carbon dioxide emissions, a greenhouse gas.

[0019] According to another feature of the invention, at least one cycle is a final cycle with a final detection step and a final increase step at the end of which the heating power level is equal to a maximum heating power level.

[0020] In other words, the final cycle is the last cycle performed by the preheating process, and this final cycle allows the system to reach the maximum heating power level, which represents the maximum thermal energy that the heating system can provide. According to the invention, this final cycle is not triggered immediately but follows at least one start-up step that raises the heating power to a threshold value. Therefore, if the key action indicating the intention to start, which must be detected during the final detection step, is not detected, the maximum heating power is not triggered, and energy savings are achieved.

[0021] According to another feature of the invention, a plurality of successive cycles are implemented after the start-up step, with at least one intermediate cycle occurring between the start-up step and the final cycle. The intermediate cycle comprises an intermediate detection step and an intermediate ramp-up step, enabling the heating power level to be raised from the threshold heating power level to an intermediate heating power level. It is understood that an intermediate heating power level is higher than the threshold heating power level and lower than the maximum heating power level.In the case of a plurality of intermediate cycles, a plurality of intermediate heating power levels can be reached successively during the process, the intermediate heating power levels being distinct from one another to form a stepwise increase in the heating level, with an intermediate heating level reached at the end of an intermediate step that is higher than the intermediate heating level that was reached at the beginning of that intermediate step.

[0022] The number of intermediate cycles and the type of key action representing the will to start which triggers such an intermediate cycle are defined beforehand by the manufacturer, each intermediate cycle having its own level of intermediate heating power.

[0023] In one scenario, the preheating process may not include any intermediate cycles, consisting only of a start-up stage and a final cycle. In this case, where only one cycle occurs after the start-up stage—namely, the final cycle—the ramp-up stage is such that the aforementioned intermediate level is equal to the maximum heating power level.

[0024] In a second scenario, the preheating process may include at least one intermediate cycle. This preheating process then comprises a start-up stage, one or more intermediate cycles, and finally a final cycle. In this case, where several cycles, including the final cycle, follow one another after the start-up stage, the ramp-up stage is such that the aforementioned intermediate level tends to approach the maximum heating power level by successively increasing the heating power level from the threshold heating power level reached after the start-up stage to the maximum heating power level, with multiple successive intermediate heating power levels.

[0025] According to an optional feature of the invention, a predefined situation that can trigger the launch step consists of detecting the proximity of the user to the vehicle.

[0026] According to an optional feature of the invention, a key action representative of a desire to start the vehicle which can be detected in an intermediate cycle consists of an action relating to the positioning of the user in contact with or within the vehicle, such as for example the opening of a vehicle door, or being present in the driver's seat.

[0027] The key actions representing a start-up intent, and whether they represent the initiation of an intermediate or final cycle, are defined by the manufacturer. A database contains all the key actions representing a start-up intent, and this database is linked to a control unit for managing the thermal system. The manufacturer implements these key actions in the database. Each key action is associated with a specific heating power level for the thermal system, linked to the aftertreatment device. This heating power level is chosen based on how closely the associated key action is performed before the vehicle actually starts.More specifically, the heating power levels corresponding to actions assumed to be very close chronologically to the actual start of the vehicle are high and close to the maximum heating power level, while the heating power levels corresponding to actions assumed to be further chronologically from the actual start of the vehicle are low, although still above the threshold heating power level for achieving the stepped increase. An action representative of an intention to start the vehicle considered to be the furthest from the actual start might, for example, be opening the door, while an action representative of an intention to start the vehicle considered to be closest to the actual start might, for example, be detecting a gesture from the user towards a starting device.Ordering the key actions representative of a desire to start allows us to gradually approach the maximum heating power level, while avoiding generating the maximum heating power level for a key action representative of a desire to start that is not the closest to starting, for example opening the driver's door, which helps to limit the number of cases where the maximum heating power is delivered when the user ultimately does not start their vehicle.

[0028] According to another feature of the invention, the key action representative of a desire to start the vehicle which can be detected in the final cycle consists of the position of the hand in the area of ​​a vehicle starting device.

[0029] Alternatively, the last key action indicating an intention to start—that is, the key action detectable in the final cycle—may be distinct from an action associated with the starting device and may consist, for example, of the user operating the clutch or brake before starting. The manufacturer chooses the last key action indicating an intention to start.

[0030] According to another feature of the invention, a verification step is configured to control the effective start-up of the vehicle, for a predetermined period of time and starting when the maximum heating power level is reached.

[0031] In other words, following the final cycle, a verification step is initiated for a period of time predetermined by the manufacturer, which can be adjusted based on the user's learned vehicle starting practices. During this period, if the starting device is activated, the preheating process is interrupted.

[0032] According to another feature of the invention, the verification step includes detecting the temperature of the post-processing device in the event that actual startup is not detected. This determines whether the post-processing device has reached its startup temperature.

[0033] The invention also relates to a preheating system configured to implement a preheating process as previously mentioned, intended to control the temperature rise of an after-treatment device of a vehicle powered at least in part by an internal combustion engine, the preheating system comprising at least a thermal system configured to increase the temperature of the after-treatment device, a detection means configured to detect a key action representative of an intention to start the vehicle, a control unit configured to drive an increase in the heating power level of the thermal system as a function of the detection of said key action.

[0034] The preheating system includes at least one thermal system such as a heating grid configured to provide heat, by means of an appropriate power supply, to the post-processing device.

[0035] The preheating system includes a control unit configured to modify the level of heating power allocated to the thermal system based on start-up intent detection information, the start-up intent detection information being a key action representative of a start intent included in a database of the control unit.

[0036] The after-treatment device may include at least a portion of the vehicle's exhaust.

[0037] According to another feature of the invention, the detection means includes at least one heterodyne sensor configured to detect a presence in an area close to a starting device, by voltage difference across the terminals of the sensor.

[0038] The preheating system includes at least one heterodyne sensor configured to establish a distance between the sensor and the driver's hand. Since the hand's position cannot be known, this detection provides a sphere of possible hand positions. This detection can be used to determine the direction of a hand and thus the driver's intention to perform an action.

[0039] According to another feature of the invention, three heterodyne sensors are positioned at a distance from each other around the area of ​​the starting device.

[0040] The preheating system may include three heterodyne sensors configured to establish a hand position in space. This position is established through triangulation of information regarding the presence of the user's hand within a detection zone common to the sensors.

[0041] Other features, details and advantages of the invention will become clearer upon reading the following description on the one hand, and the illustrative and non-limiting examples of embodiments given with reference to the accompanying drawings on the other hand, in which: [ Fig. 1 ] is the schematic representation of the components of a preheating device necessary for raising the temperature of the post-processing device, according to a preheating method according to the invention; [ Fig. 2 ] is a flowchart representing the preheating process of a post-processing device according to a first embodiment of the invention; [ Fig. 3 ] graphically illustrates the evolution of the heating power as a function of the vehicle's starting attempt in the preheating process represented by the flowchart of the figure 1 ; Fig. 4 ] is a flowchart representing the preheating process of a post-processing device according to a second embodiment of the invention; [ Fig. 5 ] graphically illustrates the evolution of the heating power as a function of the vehicle's starting attempt in the preheating process represented by the flowchart of the figure 3 ; Fig. 6 ] illustrates a variant embodiment of means for detecting the intention to start the vehicle by schematically depicting the interior of a vehicle equipped with a heterodyne sensor configured to detect an intention to start the vehicle and used in the preheating process according to the invention; [ Fig. 7 ] illustrates a variant of the implementation of the means of detecting the intention to start the vehicle by schematically representing the interior of a vehicle equipped with three heterodyne sensors configured to detect the position of an object in space.

[0042] The features, variations, and different embodiments of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, variations of the invention may include only a selection of features, described hereafter in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from prior art.

[0043] The invention relates to a preheating device for an aftertreatment system in a motor vehicle. In order to comply with increasingly stringent anti-pollution standards for vehicles powered at least partially by an internal combustion engine, it is necessary for car manufacturers to find ways to reduce the amount of polluting molecules (HC, CO, NOx, etc.) that their vehicles produce. To this end, aftertreatment devices such as catalytic converters are used in exhaust systems, reducing the release of these pollutants into the atmosphere by filtering the combustion gases emitted by vehicle engines. Furthermore, manufacturers seek to minimize CO2 emissions, a normal product of engine combustion, which is a greenhouse gas.

[0044] The aftertreatment system also includes a thermal system whose function is to increase the temperature of the aftertreatment system, possibly without starting the vehicle, and to perform a preheating operation so that the aftertreatment system is at an optimal operating temperature, for example, around 450°C, as soon as the vehicle starts. The thermal system may be an electrical device, powered by the vehicle's battery, such as a heating grid.

[0045] There figure 1 illustrates a preheating system for a post-processing device according to the invention, configured to implement the preheating process which will be described later.

[0046] The preheating system of a post-processing device 100 includes in particular a thermal system 101 and a control unit 102, in particular configured to control the thermal system 101, and it also includes a detection means 104, capable of detecting a key action AC representative of a desire to start and of communicating with the control unit 102.

[0047] The control unit 102 is configured to control the thermal system 101. More particularly, according to the invention, the control unit 102 is configured to, on the one hand, generate the ignition of the thermal system 101 and thus a step of launching the preheating process of the post-treatment device 100, and on the other hand, to control the level of heating power generated by the thermal system 101.

[0048] An advantage of the invention is to modulate the temperature rise of the after-treatment device 100 during the preheating stage in order to ensure that the after-treatment device 100 is at the correct temperature when the vehicle is started to ensure its efficiency, while avoiding use cases where the thermal system 101 is powered at full power so that it delivers maximum heat to the after-treatment device 100 when the vehicle is ultimately not started.

[0049] The control unit 102 can be specific to the thermal system 101 of the invention and exclusively dedicated to the control of the thermal system 101 enabling the preheating of the after-treatment device 100. Alternatively, the control unit 102 can be integrated into the central computer of the vehicle.

[0050] The control unit 102 includes a database in its memory, in which is implemented a list of key actions representing a start intention 103. This database also includes a heating power level of the thermal system 101 associated with each key action AC representing a start intention. In other words, the control unit generates a command instruction for the thermal system, at a given heating power level, based on the representative key action AC detected and identified by the control unit. The number of key actions representing a start intention in the list implemented in the database is chosen by the manufacturer and can therefore vary from one vehicle application to another.

[0051] Detection means 104 is configured to detect the occurrence of a key action AC indicative of an intention to start the engine. A specific detection means is required for each key action indicative of an intention to start. The detection of key actions indicative of an intention to start can also be implemented by reusing detection means already present on the vehicle, such as seat presence sensors.

[0052] As described below, this type of control unit operation allows for the activation of intermediate heating power levels to progressively increase the temperature of the aftertreatment device 100. Specifically, the heating level progresses from a threshold level reached after a start-up step, enabling an initial temperature increase, to a maximum heating level reached after a final cycle. In one embodiment, the control unit's database contains only one key action representing an intention to start, and the preheating process then comprises only the start-up step and the final cycle initiated by the detection of this single key action. As a non-limiting example, as detailed below, this single key action representing an intention to start could be the presence of the driver's hand near the start-up device 2.In another embodiment, the control unit includes in its database a plurality of key actions representative of an intention to start the engine, which necessitates a plurality of detection methods. The various representative key actions and their associated detection methods are chosen by the manufacturer, depending on the presence of these detection methods on the vehicle and / or on the relevance of the action in question to representing an intention to start the engine. The preheating process then includes the starting stage, the final cycle, which can again be initiated by detecting the presence of the driver's hand near the start button, and at least one intermediate cycle, which can be generated by the detection of other key actions.

[0053] The appearance of a predefined situation initiates the preheating process launch step; this predefined situation can be either an automatic, daily situation for example, or a situation occurring more or less remotely from the vehicle, such as the launch of a preheating by the user via a suitable application.

[0054] Key actions representative of a desire to start may include, but are not limited to, a link between the user and the vehicle when the user is outside the vehicle, such as an action by the user on the vehicle key or the detection of the user's hand in the vehicle handle, or a link between the user and the vehicle such as the opening of a vehicle door, or the presence of the user in one of the vehicle seats.

[0055] The detection methods used to detect these key actions can be methods specifically dedicated to these detections or existing methods, such as an open door detection sensor already present on the majority of current vehicles, a seatbelt buckle detection sensor or a pressure sensor present in the driver's seat.

[0056] It should be noted that each of the actions just given as examples of key actions representative of the will to start could also form the predefined situation as previously mentioned, namely the situation which triggers the start-up step of the preheating process.

[0057] There figure 1 This also illustrates a sequence of steps in the preheating process according to one aspect of the invention, implemented by the preheating device as described above. When a key action AC representing an intention to start is detected by the detection means 104, the detection information is sent to the control unit 102. The control unit 102 analyzes the relevance of the received data, notably by comparing the detection information to the list of representative key actions 103 stored in the database associated with the control unit 102. The control unit then identifies the representative key action and the associated heating power level. After this analysis, the control unit 102 communicates instructions to the thermal system 101 to modify the heating power level, thereby enabling the temperature of the aftertreatment device 100 to be changed.

[0058] THE figures 2 And 3illustrate more particularly a first embodiment of the preheating process in which two main steps take place, including a launch step 6 and a final cycle 40 comprising a final detection step 7 and a final increase step 9 of the heating power level of the thermal system.

[0059] As illustrated in the flowchart shown on the figure 2 The preheating process begins with the launch step 6, initiated by the occurrence of a predefined situation. The launch step brings the heating power level of the thermal system to a threshold power level.

[0060] In this first embodiment of the preheating process, the start-up step is followed by the final cycle 40, which begins with the final detection step 7 as described above. If the key action AC, indicating an intention to start, is not detected 23, then the heating power level remains unchanged and a new final detection step 7 is initiated. If the key action AC, indicating an intention to start, is detected 24, then the final ramp-up step 9 is initiated and the control unit drives the heating system to bring it to a maximum heating power level 26.

[0061] There figure 3 illustrates the evolution of the heating power level of the thermal system 101 during the preheating process, here expressed as a percentage of the maximum heating level, with in particular a threshold heating level 22 and a maximum heating level 26. Curve 20 is representative of the temperature of the post-treatment device 100 as a function of time since the start of the preheating process and the heating power level.

[0062] As can be seen on the figure 3 The launch step 6 is such that the control unit 102 drives the thermal system 101 to operate at a threshold heating level 22, here on the order of 40% of the maximum heating power of the thermal system, so that the temperature of the post-treatment device 100 increases gradually over time, according to an initial increase 28 noticeable on the curve 20. When the key action representing a desire to start is detected during the final detection step 7 initiating the final cycle 40, the final increase step 9 triggers the increase in the heating power level to the maximum level 26. The temperature of the post-treatment device 100 therefore increases more rapidly over time, forming the final increase slope 30 visible on the curve 20, which brings the post-treatment device 100 to the desired temperature.The final cycle 40 in this process is represented by the succession of the final detection step 7 and the final augmentation step 9.

[0063] THE figures 4 And 5 illustrate a second embodiment of the preheating process which here comprises at least 3 major steps including a launch step 6 and a final cycle 40 similar to what has been described, as well as at least one intermediate cycle 42 between the launch step and the final cycle and including an intermediate detection step 8 and an intermediate increase step 10.

[0064] As illustrated in the flowchart shown on the figure 4 The preheating process according to the second embodiment begins, as in the first embodiment, with the start-up step 6, again initiated by the occurrence of a predefined situation. This step brings the heating power level to a threshold power level 22, which constitutes the first stage of increasing heating power. Unlike the first embodiment, the start-up step is not directly followed by the final cycle 40, but by at least one intermediate cycle 42 between the start-up step 6 and the final cycle 40. Each of these intermediate cycles allows the heating power level of the thermal system to be raised in stages, from the threshold power level 22 to the maximum power level, passing through intermediate power levels.

[0065] In this second embodiment of the preheating process, the start-up step is followed by an intermediate cycle 42, which begins with an intermediate detection step 8. If a key action AC indicating an intention to start is not detected 32, then the heating power level remains unchanged and a new intermediate detection step 8 is initiated. If a key action AC indicating an intention to start is detected 34, then the intermediate ramp-up step 10 is initiated and the control unit drives the thermal system to bring it to an intermediate threshold level 44.The succession of the intermediate detection step 8 and the intermediate augmentation step 10 thus forms an intermediate cycle 42 specific to this second embodiment which can be followed either by another intermediate cycle, with a new intermediate detection step which follows said intermediate augmentation step and a new augmentation step.

[0066] One or more of the intermediate cycles 42 is followed by the final cycle 40 when the detection 34 of a key action AC, indicative of an intention to start the vehicle, relates to the key action AC listed in 103 that the manufacturer has deemed closest to an actual vehicle start. As described previously, the final cycle 40 is triggered by bringing the heating power level of the thermal system to its maximum power level 26.

[0067] The second embodiment as just mentioned is also notable in that it includes a verification step 46, which is launched when the maximum heating power level 26 is reached.

[0068] Verification step 46 consists of a control phase during which it is verified that the vehicle has started, for example, by checking that an action is performed on the starting device 2, such as turning the vehicle key, for a defined period of time after the start of the verification step. If it is found that the starting device 2 is engaged, a first operation 48 is generated to stop the preheating process. If, on the other hand, it is detected that the starting device is not engaged, a second operation 50 is generated to check the activation of the aftertreatment device by measuring the temperature of the aftertreatment device.

[0069] When a first result 54 indicates that the aftertreatment device 100 has not reached its start-up temperature, the heating power level remains at its maximum, and the second operation is run in a loop until the start-up temperature is reached. Alternatively, when a second result 56 indicates that the aftertreatment device 100 has reached its start-up temperature, the heating power level is reduced to a lower level, which may be the threshold heating power level 22 or an intermediate heating power level 44. Reducing the heating power to such a lower level maintains the thermal inertia of the aftertreatment device 100 while reducing the electrical consumption of the heating system 101.

[0070] It should be noted that although verification step 46 has only been illustrated in the second embodiment, it can also be implemented, without leaving the context of the invention, in the first embodiment of the preheating process.

[0071] There figure 5 illustrates the evolution of the percentage of the heating level of the thermal system during the preheating process, here expressed as a percentage of the maximum heating level, with in particular a threshold heating level 22, an intermediate heating level 44 and a maximum heating level 26. Curve 60 is representative of the temperature of the post-treatment device 100 as a function of time since the start of the preheating process and the heating power level.

[0072] As can be seen on the figure 5 The start-up step 6 is such that the control unit 102 drives the thermal system 101 to operate at an initial threshold heating level 22, here approximately 30% of the thermal system's maximum heating power. As a result, the temperature of the post-treatment device 100 gradually increases over time, with a noticeable initial increase 62 on the curve 60, bringing the system to this initial temperature level. When a key action indicating a start-up intent is detected during the intermediate detection step 8 of the intermediate cycle 42, the intermediate increase step 10 triggers an increase in the heating power level to an intermediate threshold heating power level 44, here 70%. The first intermediate cycle 42 is then complete.This increase in power results in a faster increase in the temperature of the post-processing device 100, this increase 64 being noticeable on the curve 60 of the . figure 5 The final cycle 40 concludes this preheating process 4 by increasing the heating power level to its maximum heating power level 26, the final increase 30 in the temperature of the post-treatment device 100, visible on curve 60 of the figure 5 , thus being as fast as possible.

[0073] The preheating process can include a plurality of intermediate cycles 42 between the start-up step 6 and the final cycle 40. The second embodiment is not limiting to the number of possible intermediate cycles 42, the number of intermediate cycles 42 between the start-up step 6 and the final cycle 40 being a function of the representative key actions detected and reported to the control unit.

[0074] The power levels allocated to the thermal system 101 during the various stages, which depend on the type of key action AC indicating a start-up, can vary based on learning performed by the control unit. In other words, the system records the last cycles implemented during previous preheating operations and the resulting energy consumption, in order to optimize energy consumption for subsequent preheating operations, and in particular the different heating thresholds associated with the detection of key actions AC.

[0075] We will now describe an example of the implementation of a detection method, with reference to figures 6 et 7 , it being understood that this example implementing at least one heterodyne sensor is to be considered as a non-limiting example of the invention.

[0076] The at least one heterodyne sensor comprises a pair of oscillators, with a variable-frequency oscillator having an antenna and a fixed-frequency oscillator without an antenna. The frequency of the variable-frequency oscillator is capable of being changed depending on the passage of the user's hand through the detection field of the variable-frequency oscillator's antenna.

[0077] When nothing interferes with the antenna's detection field, the frequency of the variable-frequency oscillator remains constant, that is, approximately equal to the frequency of the fixed-frequency oscillator. When a body, particularly the user's hand, enters the antenna's detection field, the body alters the frequency of the variable-frequency oscillator. The frequencies of each oscillator are processed by a dedicated computer, and the resulting output signal varies according to the frequencies of each oscillator, and specifically according to the variation in the frequency of the variable-frequency oscillator. Analysis of the output signal allows the distance between the body and the sensor to be determined, providing a sphere of possible positions for the body relative to the heterodyne sensor.

[0078] There figure 6 represents an embodiment in which a single heterodyne sensor 66 is used. In this embodiment, the heterodyne sensor 66 is located near the starting device 2. When the driver's hand is located in the detection zone 68 of the sensor 66, the heterodyne sensor 66 is therefore able to determine the distance between the hand and the starting device.This results in information about the position of the user's hand relative to the button on the starting device, and the control unit can process this raw information, in particular by triggering an action on the thermal system when the distance between the hand and the starting device is less than a threshold distance, or in a more analytical way by taking into account the evolution of this distance value between the user's hand and the starting device, in particular by triggering an action on the thermal system when the distance, below a certain threshold, tends to decrease.

[0079] There figure 7This represents a variant embodiment in which three heterodyne sensors 70 are used, distributed around the starting device 2. For example, a first heterodyne sensor is positioned approximately in the steering wheel area, and a second and third heterodyne sensors are positioned at a distance from each other on the dashboard. Each heterodyne sensor functions as previously described and sends information back to the control unit when a hand is detected, i.e., when it is within the detection zone 68 around the heterodyne sensor. The use of three heterodyne sensors 70 allows the hand position to be triangulated, thus providing precise information without needing to locate the sensor on the starting button as previously described.

[0080] The invention, as described above, achieves its intended purpose and provides a method for preheating a post-treatment device using successive temperature steps. The heating power level evolves throughout the process, following an initial start-up step and as key actions indicating an attempt to start the vehicle are detected. According to the invention, this preheating method is particularly attractive because it prevents the waste of electrical energy from the battery during false starts and, on a larger scale, reduces CO2 emissions by minimizing the drag on the alternator used to recharge the battery once the vehicle has started.The preheating process is also attractive because it takes into account the thermodynamics of the materials in the post-treatment device, as excessively rapid and repeated heating of the post-treatment device can be detrimental to the materials within it. Variations not described here could be implemented without departing from the scope of the invention, provided that, in accordance with the invention, they employ a preheating process consistent with the invention, with successive steps to increase the heating level.

Claims

1. Method for preheating for controlling the rise in temperature of an after-treatment device (100) of a vehicle motorized at least in part by an internal combustion engine, the method for preheating comprising a launch step (6) for preheating the after-treatment device (100) to a threshold heating power level (22, 44), and at least one cycle (40, 42) following the launch step (6), this cycle (40, 42) comprising a detection step (7, 8) of detecting a user action included in a list of key actions representative of a starting intention (103) of the vehicle, and characterized by a step of increasing (9, 10) the heating power level to a higher heating power level when a key action representative of a starting intention (103) of the vehicle is detected.

2. The method for preheating according to the preceding claim, wherein the at least one cycle is a final cycle (40) with a final detection step (7) and a final increase step (9) at the end of which the heating power level is equal to a maximum heating power level (26).

3. The method for preheating according to the preceding claim, wherein a plurality of successive cycles are implemented after the launch step, with at least one intermediate cycle (42) taking place between the launch step (6) and the final cycle (40), the intermediate cycle (42) comprising an intermediate detection step (8) and an intermediate increase step (10) for changing the heating power level from the threshold heating power level to an intermediate heating power level (22, 44).

4. The method for preheating according to the preceding claim, wherein a key action representative of a starting intention (103) of the vehicle that can be detected in an intermediate cycle (42) consists of an action relating to the positioning of the user in contact with or within the vehicle.

5. The method for preheating according to one of claims 2 to 4, wherein the key action representative of a starting intention (103) of the vehicle that can be detected in the final cycle (40) consists of the position of the hand in the area of a vehicle starting device (2).

6. The method for preheating according to one of the preceding claims, wherein a verification step (46) is configured to detect the actual starting of the vehicle, for a predetermined period of time and beginning when the maximum heating power level (26) is reached.

7. The method for preheating of the preceding claim, wherein the verifying step (46) comprises detecting the temperature (52) of the after-treatment device in the event that the actual start is not detected.

8. Preheating system configured to implement a method for preheating according to one of the preceding claims, intended to control the rise in temperature of an after-treatment device (100) of a vehicle motorized at least in part by an internal combustion engine, the preheating system comprising at least one thermal system (101) configured to increase the temperature of the after-treatment device (100), a detection means (104) configured to detect a starting intention of the vehicle, a control unit (102) configured to control an increase in the heating power level of the thermal system (101) according to the detection of the key action.

9. Preheating system according to the preceding claim, wherein the detection means (104) comprises at least one heterodyne sensor (66) configured to detect a presence in an area close to a starting device, by voltage difference across the sensor.

10. The preheating system according to the preceding claim, wherein three heterodyne sensors (70) are positioned at a distance from one another around the area of the starting device (2).

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