Method and system for controlling a supercharged controlled ignition internal combustion engine configured to purge an intake air cooler

Description

1 / 15 “METHOD AND SYSTEM FOR CONTROLLING A SUPERCHARGED AND CONFIGURED CONTROLLED IGNITION INTERNAL COMBUSTION ENGINE "TO PURGE AN INTAKE AIR COOLER" FIELD OF THE INVENTION

[001] The present invention relates to the field of spark-ignition internal combustion engines, in particular for motor vehicles, and more particularly to supercharged internal combustion engines, running on gasoline, alcohol or LPG, comprising a partial exhaust gas recirculation system in the engine intake.

[002] More particularly, the invention relates to reducing condensation, or even purging, in an intake air cooler.

[003] As emissions standards for internal combustion engines, such as diesel engines, become increasingly stringent, these engines are generally designed with Exhaust Gas Recirculation (EGR) systems. Such EGR systems typically comprise a recirculation circuit for the high-pressure exhaust duct that collects exhaust gases upstream of the turbocharger turbine, a recirculation circuit for the low-pressure exhaust duct that collects exhaust gases downstream of an exhaust line depollution device, and a heat exchanger to cool the gases present in the low-pressure recirculation circuit and reintroduce them into the engine intake. The low-pressure EGR circuit allows the burnt combustion gases to be drawn back into the intake and reintroduced upstream of the supercharger.

[004] These inert gases allow, in particular, to increase the total mass of gas admitted into the combustion chamber in a gasoline engine, which reduces the need to reduce the intake manifold pressure to manage the air charge. This limits pumping losses and improves combustion, resulting in a reduction in fuel consumption. Petition 870250088325, dated 09 / 29 / 2025, page 8 / 28 2 / 15

[005] More specifically, the present invention relates to gas recirculation systems comprising a Cold Water Charge Air Cooler (WCAC) located downstream of the turbocharger system compressor and upstream of the intake manifold.

[006] To meet emission standards, internal combustion engines may be required to use a low-pressure cold gas recirculation circuit. However, the low-pressure gas recirculation circuit contains burnt gases laden with water. Thus, when the engine is cold, there is a risk of condensation of the water present in the gas recirculation system in the intake air cooler.

[007] The use of a low-pressure EGR circuit therefore leads to problems of water condensation in the engine intake circuit. This water usually originates from the moisture in the fresh air coming from the fresh air intake and / or from water vapor contained in the exhaust gases recirculated by the low-pressure EGR circuit.

[008] This condensed water can then carry: - to the projection of liquid water droplets upstream of the compressor, resulting in premature wear of the compressor wheel; - due to the accumulation of water in low points of the intake circuit, resulting in corrosion problems, for example, of the intake air cooler or the EGR cooler. - to the formation of ice in the intake system under extreme environmental conditions, either during driving or during engine cooling. The slow and progressive accumulation, concomitant with freezing, can lead to ice buildup. When the ambient temperature exceeds 0°C, this ice turns into liquid, which can cause corrosion or premature wear of the compressor wheel. This water can also be sucked into the engine, especially during the cooling phase. Petition 870250088325, dated 09 / 29 / 2025, page 9 / 28 3 / 15 match, and damage it.

[009] Furthermore, during operating phases that promote water condensation, for example, due to environmental conditions such as high ambient humidity and / or low ambient temperature, or due to engine operation, the water vapor contained in the fresh air and EGR gas mixture tends to condense in the intake circuit and, in particular, on the surface of the intake air cooler.

[010] This water accumulates in the cooler and can be desorbed, which can interrupt or even extinguish engine combustion. In fact, the accumulation of water in the intake air cooler can be followed by a sudden release phenomenon, especially during a sharp increase in the flow rate of the air-EGR mixture drawn into the engine, for example, after a full load request when the driver presses the accelerator pedal. This sudden release of liquid water into the combustion chamber can lead to rapid combustion cooling, i.e., the absence of torque generation or misfire, which can, in the long term, damage the engine or some of its associated components such as a catalytic converter.

[011] To avoid this condensation phenomenon, the engine operates with the high-pressure exhaust gas recirculation circuit while waiting for the intake line temperature to reach a limit value to prevent condensation in the intake air cooler.

[012] Document FR 3 064 678 - B1 proposes a solution to estimate the risk of condensation in the intake air cooler in order to control the exhaust gas recirculation system. Thus, in case of water accumulation in the intake air cooler, the EGR valve is closed to await favorable conditions to evacuate the condensed water. However, this solution is not satisfactory, as it requires the EGR valve to remain closed for a long period, which leads to a deterioration in fuel consumption. Petition 870250088325, dated 09 / 29 / 2025, page 10 / 28 4 / 15

[013] There is a need to improve the management of liquid water storage and desorption in the intake circuit and, more particularly, in the intake air cooler of a supercharged spark-ignition internal combustion engine.

[014] Therefore, the objective of the present invention is to provide a method and engine control system configured to manage the storage and desorption of liquid water in the intake air cooler.

[015] The object of the present invention is a method for controlling a spark-ignition internal combustion engine comprising at least one cylinder, a fresh air intake manifold supplied with fresh air through a duct, a turbocharger compressor and a heat exchanger downstream of said compressor and upstream of the intake manifold, the engine further comprising an exhaust circuit comprising, from upstream to downstream in the direction of the flow of the burned gases, an exhaust manifold, a turbocharger turbine and, for example, a system for emitting the combustion gases from the engine.

[016] The engine further comprises a partial recirculation circuit for intake exhaust gases, originating at a point in the exhaust circuit downstream of said turbine, and opening into the fresh air supply duct upstream of the turbocharger compressor, said intake circuit comprising a throttle valve or throttle body mounted between the compressor and the heat exchanger.

[017] According to the method: - to estimate the mass of liquid water stored in real time on the inner walls of the heat exchanger; - to estimate the mass of water compared to a limit value; and - activate the intake air cooler purge when the estimated water mass exceeds the limit value, generating oscillations in the intake airflow entering the exchanger between a nominal flow rate and an increased flow rate, and Petition 870250088325, dated 09 / 29 / 2025, page 11 / 28 5 / 15 oscillations of ignition timing advance between a nominal advance value and a degraded advance value.

[018] These variations in intake airflow allow the accumulated water on the cooler walls to be forced to stop, maintaining a stable engine torque around the torque setpoint.

[019] The heat exchanger can be a Water-Cooled Intake Air Cooler (W-CAC) or an Intake Air Cooler (CAC).

[020] Advantageously, intake airflow oscillations are obtained by controlling the opening of the adjustment valve or throttle body, performing oscillations between a nominal position corresponding to an engine operating point and an increased opening position, i.e., an additional opening greater than the nominal position. In one possible embodiment, the increased opening position may be the maximum opening position, i.e., the fully open position, of the throttle body.

[021] Advantageously, the generation of oscillations in the intake airflow entering the exchanger and the generation of oscillations in the ignition timing advance are performed simultaneously.

[022] For example, oscillations or variations in intake airflow form oscillating steps between the nominal flow rate and the increased flow rate, and the generation of ignition timing advance oscillations forms oscillating steps between the degraded advance value and the nominal advance value, the nominal value of the ignition timing advance corresponding to the nominal position of the intake airflow and, in particular, of the adjustment valve or throttle body. The degraded advance value corresponds to an advance value lower than the nominal advance value, which degrades combustion efficiency.

[023] The oscillating steps can, for example, have an identical time period between the ascent and descent phases, for example, between 1 and 2 s, for example Petition 870250088325, dated 09 / 29 / 2025, page 12 / 28 6 / 15 equals 1.5 seconds.

[024] Advantageously, the purge stage has a duration necessary to evacuate the water from the intake air cooler, between 8 and 12 s, for example, equal to 10 s.

[025] According to a second aspect, the invention relates to an electronic control unit for a spark-ignition internal combustion engine, comprising at least one cylinder, a fresh air intake manifold supplied with fresh air by means of a duct, a turbocharger compressor and a heat exchanger downstream of said compressor and upstream of the intake manifold, the engine further comprising an exhaust circuit comprising, from upstream to downstream in the direction of the flow of the burned gases, an exhaust manifold, a turbocharger turbine and, for example, a system for emitting the combustion gases from the engine.

[026] The engine further comprises a partial recirculation circuit for the intake exhaust gases, originating at a point in the exhaust circuit downstream of said turbine, and opening into the fresh air supply duct upstream of the turbocharger compressor, said intake circuit comprising an adjustment valve or throttle body mounted between the compressor and the heat exchanger.

[027] The electronic control unit comprises an engine control system comprising: - a module to estimate the mass of liquid water stored in real time on the inner walls of the heat exchanger; - a module to compare the estimated mass of water with a limit value; and - a module to activate the purge of the intake air cooler when the estimated mass of water exceeds the limit value, the module being configured to generate oscillations in the intake air flow rate entering the exchanger between a certain flow rate value. Petition 870250088325, dated 09 / 29 / 2025, page 13 / 28 7 / 15 nominal and an increased flow rate value, and oscillations in ignition timing advance between a nominal advance value and a degraded advance value.

[028] Advantageously, the module for activating the intake air cooler purge comprises a module for controlling the adjustment valve or throttle body, performing oscillations between a nominal position corresponding to an engine operating point and an additional open position.

[029] Advantageously, the module for activating the intake air cooler purge comprises a module for modulating the ignition timing advance configured to modulate the ignition timing advance between the nominal advance value and a degraded advance value.

[030] According to another aspect, the invention relates to a motor vehicle comprising an electronic control unit as described above.

[031] Other objectives, features and advantages of the invention will become apparent from reading the following description, given only by way of non-limiting example, and made with reference to the accompanying drawings, in which:

[032] Figure 1 represents, in a very schematic way, an exemplary structure of an internal combustion engine of a motor vehicle comprising a control unit comprising a control system according to the invention.

[033] Figure 2 illustrates square wave curves of the control signals from the control system according to Figure 1.

[034] Figure 3 shows the block diagram of a control method according to the invention, implemented by the control unit of Figure 1.

[035] Figure 1 schematically represents the general structure of an internal combustion engine 10, of the spark ignition type, operating in particular with gasoline, of a motor vehicle. As a variant, it can be an engine powered by alcohol or liquefied gas of the LPG type. Petition 870250088325, dated 09 / 29 / 2025, page 14 / 28 8 / 15

[036] These architectures are presented by way of example and do not limit the invention to the single configuration to which motor control according to the invention can be applied.

[037] In the illustrated example, the internal combustion engine 10 comprises, but is not limited to, three cylinders in line 12, a fresh air intake manifold 14, an exhaust manifold 16 and a turbocharging system or turbocharger 18.

[038] Cylinders 12 are supplied with air through the intake manifold 14, or intake distributor, supplied with air through a duct 20 provided with an air filter 22 and the turbocharger 18b of engine 10.

[039] Each cylinder 12 is supplied with fuel, for example, gasoline.

[040] As is known, the turbocharger 18 essentially comprises a turbine 18a driven by the exhaust gases and a compressor 18b mounted on the same shaft as the turbine 18a, ensuring the compression of the air distributed by the air filter 22, with the aim of increasing the quantity (mass flow rate) of air admitted into the cylinders 12 of the engine 10. The turbine 18a may be of the “variable geometry” type, i.e., the turbine rotor is equipped with vanes of variable inclination to modulate the amount of energy extracted from the exhaust gases and, consequently, the boost pressure.

[041] A heat exchanger 26 is placed after the compressor outlet 18b, equipping the intake manifold 14a duct 14 with fresh air.

[042] The internal combustion engine 10 therefore comprises an intake circuit Ca, an exhaust circuit Ce and a fuel injection circuit (not shown).

[043] The intake circuit Ca comprises, from upstream to downstream, in the direction of air circulation: Petition 870250088325, dated 09 / 29 / 2025, page 15 / 28 9 / 15 - 22 air filter or air box; - compressor 18b of turbocharger 18, configured to compress air collected from the outside atmosphere and, if necessary, recycled exhaust gases at low pressure, as will be described later; - a 24-butterfly housing or a gas intake valve in the engine; - a heat exchanger 26 configured to cool the intake gases corresponding to a mixture of fresh air and recycled gases after they have been compressed in the compressor 18b; and - intake manifold 14.

[044] Heat exchanger 26 is a cooler for so-called “supercharged” intake gases, corresponding here to an air-to-water exchanger, called a “water loaded air cooler” in English. The terms “heat exchanger 26” and “intake air cooler” below refer to the same element. Alternatively, it may be an air-to-air cooler.

[045] The intake circuit Ca may also comprise a flow meter (not shown) disposed in the intake duct 20 downstream of the air filter 22; the flow meter being configured to measure the actual value of the air flow entering the engine 10. The flow meter measures only the fresh air flow.

[046] The exhaust circuit Ce comprises, from upstream to downstream, in the direction of the flow of the burned gases: - 16" exhaust manifold; - turbine 18a of turbocharger 18 configured to extract energy from the exhaust gases passing through it, this expansion energy being transmitted to compressor 18b via the common shaft, for compression of the intake gases; - a combustion gas emission control system 40.

[047] With regard to exhaust manifold 16, this recovers the exhaust gases from combustion and discharges them to the outside through an exhaust duct. Petition 870250088325, dated 09 / 29 / 2025, page 16 / 28 10 / 15 leading to turbine 18a of turbocharger 18 and through an exhaust line 30 mounted downstream of said turbine 18a.

[048] By way of non-limiting example, the engine's combustion gas emission control system 40 comprises a first device 42 comprising a three-way catalyst.

[049] The emission control system 40 further comprises a second device 55, which in this case is a fine particulate filter, and an exhaust pipe 32 mounted at the outlet of the second emission control device 55 and opening outwards.

[050] As illustrated, the engine (10) comprises a partial exhaust gas recirculation (EGR) circuit (50) in the intake, referred to as the “exhaust gas recirculation” circuit in Anglo-Saxon terminology.

[051] This circuit 50, here a low-pressure exhaust gas recirculation circuit, called “EGR BP”, originates at a point in the exhaust line 30, here, in the exhaust pipe 32, downstream of said turbine 18a, and in particular, in the case of Figure 1, downstream of the gas emission control system 40, and returns the exhaust gases to a point in the fresh air supply duct 20, upstream of the compressor 18b of the turbocharger 18, in particular downstream of the air filter 22.

[052] In a variant not shown, the low-pressure exhaust gas recirculation circuit could originate at the turbine outlet 18a, or downstream of only part of the gas emission control system 40, for example, between the first and second emission control devices 42, 55.

[053] As illustrated, this recirculation circuit 50 comprises, in the direction of the recirculated gas flow, a “V EGR BP” regulating valve 52 configured to adjust the exhaust gas flow at low pressure and an EGR gas cooler 54. The “V EGR LP” valve 52 is disposed upstream of the cooler 54 and said cooler 54 is disposed upstream of the compressor 18b. Petition 870250088325, dated 09 / 29 / 2025, page 17 / 28 11 / 15

[054] By way of non-limiting example, the engine is associated with a fuel circuit comprising, for example, fuel injectors (not referenced) that inject gasoline directly into each cylinder from a fuel tank (not shown).

[055] The engine comprises an electronic control unit (ECU) 60 comprising a control system 70 configured to control the various elements of the internal combustion engine and, in particular, the throttle body (24) and the ignition timing advance.

[056] The control system 70 receives data collected by sensors at different locations on the engine or makes estimates.

[057] The control system 70 could receive other data, such as temperatures at different locations in the engine, or other pressures.

[058] The control system 70 comprises a module 71 for estimating the mass M_water of liquid water stored in real time on the inner walls of the exchanger 26.

[059] The estimation of the mass M_water of liquid water stored in real time on the inner walls of the exchanger 26 can be carried out, for example, as a function of the temperature of the fresh air admitted, the air flow rate obtained by the flow meter, and an estimate of the ambient relative humidity, either by means of a humidity sensor located in the intake circuit Ca, for example, in the flow meter, or outside the vehicle, or by a meteorological service, especially if the vehicle is a so-called “connected” vehicle, or by the method described in patent FR 3 064 678-B1.

[060] The control system 70 comprises a module 72 for comparing the estimate of the water mass M_water with a limit value S.

[061] The limit value S may correspond to a maximum mass of liquid water that can be stored in the exchanger 26.

[062] To determine the limit value S, the exchanger 26 can, for example, be Petition 870250088325, dated 09 / 29 / 2025, page 18 / 28 12 / 15 weighed in dry state. The volume normally traversed by the air and EGR gas mixture is completely filled with water. Said exchanger 26 is installed on a test bench and blown with a constant airflow until the water contained therein is mechanically evacuated, without waiting for the water to evaporate. Then, exchanger 26 is weighed to estimate the mass of retained water. This mass corresponds to the limit value S of storable liquid water, for the constant air flow rate considered.

[063] Alternatively, the limit value S could correspond to a critical mass of water corresponding to the mass of water that is at risk of rapidly cooling the combustion if a desorption phenomenon occurs, for example, in the case of a large increase in the airflow admitted by the engine, after an acceleration request, for example.

[064] The critical mass of water can be estimated by means of tests, on a stationary engine bench, injecting an increasing mass of liquid water into the cylinder intake and measuring the internal combustion pressure, which allows estimating the indicated torque produced. Then, the maximum permissible mass of liquid water per combustion cycle and per cylinder, corresponding to a combustion defect, is deduced.

[065] The critical mass of water for the engine can then be deduced by knowing the engine dynamics, i.e. the duration and therefore the number of combustion cycles required to reach a critical stage for the engine.

[066] The control system 70 comprises a module 74 to activate the purge of the cooler 26 when the estimated mass of water M_water is greater than the limit value S.

[067] The purge activation module (74) comprises a throttle body control module (76) configured to generate variations in intake air flow between a nominal flow value (Qaf_name) and an increased flow value (Qaf_+). These variations in intake air flow are obtained by controlling the Petition 870250088325, dated 09 / 29 / 2025, page 19 / 28 13 / 15 throttle body opening (24) with oscillations between a nominal position (%BP_name) corresponding to the relevant engine operating point and an additional opening position (%BP_+). In one embodiment, said increased flow rate value may be equal to the maximum engine flow rate value corresponding to the fully open throttle body position. More generally, it is a flow rate value greater than the nominal flow rate value.

[068] These variations in intake airflow allow the accumulated water on the walls of the refrigerators 26 to stop flowing.

[069] These variations in intake airflow are obtained by means of grooves in the throttle body opening 24, between a nominal position %BP_name of the engine operating point in question and an additional opening position %BP_+.

[070] The purge activation module 74 further comprises a module for modulating the ignition timing advance 78, configured to modulate the ignition timing advance between a nominal advance value AV_name and a degraded advance value AV_-. “Degraded advance” means an advance value lower than the nominal advance value, resulting in a reduction in combustion efficiency.

[071] The values ​​for air flow rate Qaf and ignition timing advance AV are provided by an engine computer (not shown) integrated into the ECU, which comprises pairs of air flow rate / ignition timing advance values ​​for a given engine speed / load operating point.

[072] Modulating the ignition timing advance allows the engine torque to be maintained at a constant level, equal to the engine torque requested by the driver when pressing the accelerator pedal.

[073] In fact, starting from an optimal operation, corresponding to the nominal airflow Qaf_name and the nominal advance Av_name (generally corresponding to the optimal advance or a value close to the optimal advance), and increasing the airflow, Petition 870250088325, dated 09 / 29 / 2025, page 20 / 28 14 / 15 Maintaining normal spark-ignition engine operation at a stoichiometric ratio of 1, an undesirable excess of engine torque would be obtained if the advance were not degraded, since the air-fuel mixture flow rate would be higher while the combustion efficiency remained the same. A controlled degradation of the advance allows, here, the combustion efficiency to be degraded so that the same engine torque is obtained with the nominal air flow rate and nominal advance.

[074] Figure 2 shows, respectively, step-shaped curves of the intake air flow rate Qaf through the heat exchanger 26, the ignition advance AV, the engine torque C and the throttle opening percentage %BP, as a function of time in seconds.

[075] As can be seen in Figure 2, variations in intake air flow form oscillating steps between the nominal flow value Qaf_name and the increased flow value Qaf_+, and the ignition advance modulation forms oscillating steps between the degraded advance value AV_- and the nominal advance value AV_name, the nominal position of the ignition advance corresponding to the nominal position of the throttle body 24 and the intake air flow.

[076] The slots preferably have an identical time period τ between the ascending and descending phases, for example, between 1 and 2 s, for example, equal to 1.5 s.

[077] For example, the duration of the purge phase δt required to evacuate the water from the refrigerator 26 is between 8 and 12 s, for example, equal to 10 s.

[078] As illustrated in detail in Figure 3, the motor control method 100 includes a step 102 to estimate the mass M_water of liquid water stored in real time on the inner walls of the exchanger 26.

[079] Method 100 for controlling the motor also includes a step 104 of comparing the estimate of the water mass M_water with a limit value S.

[080] Method 100 for controlling the motor also includes a step 110 Petition 870250088325, dated 09 / 29 / 2025, page 21 / 28 15 / 15 activate the purge of refrigerator 26 when the estimated mass of water M_water is greater than the limit value S.

[081] Step 110 of activating the purge of the heat exchanger 26 comprises a step 112 of controlling the throttle body 24, during which the opening of the throttle body is generated by performing oscillations between a nominal position %BP_name of the relevant engine operating point and an additional opening position %BP_+, in order to generate variations in the intake air flow rate between a nominal flow rate value Qaf_name and an increased flow rate value Qaf_+.

[082] Step 110 of activating the purge of heat exchanger 26 further comprises a step 114 of modulating the ignition timing advance, configured to modulate the ignition timing advance between a nominal advance value AV_name and a degraded advance value AV_-.

[083] As explained earlier, ignition timing advance modulation allows engine torque to be maintained at a constant level equal to the engine torque requested by the driver when pressing the accelerator pedal.

[084] Step 112 of controlling the throttle body 24 and step 114 of modulating the ignition timing advance are performed simultaneously.

[085] Thanks to the invention, it is possible to purge the air cooler to avoid any risk of desorption and rapid cooling of the engine combustion, keeping the torque generated by the engine constant around a target value. Petition 870250088325, dated 09 / 29 / 2025, page 22 / 28

Claims

1 / 3 CLAIMS 1. Method (100) for controlling a spark-ignition internal combustion engine (10) comprising at least one cylinder (12), a fresh air intake manifold (14) supplied with fresh air through a duct (20), a compressor (18b) of a turbocharger (18) and a heat exchanger (26) downstream of said compressor (18b) and upstream of the intake manifold (14), the engine further comprising an exhaust circuit (Ce) comprising, from upstream to downstream in the direction of the flow of the burned gases, an exhaust manifold (16), a turbine (18a) of the turbocharger (18) and a partial recirculation circuit (50) of the exhaust gases in the intake, originating at a point in the exhaust circuit (Ce), downstream of said turbine (18a), and opening outwards into the fresh air supply duct (20), upstream of the compressor. (18b) of the turbocharger (18),the said intake circuit (Ca) comprising an adjustment valve (24) mounted between the compressor (18b) and the heat exchanger (26), CHARACTERIZED in that it comprises: - estimating the mass (M_water) of liquid water stored in real time on the inner walls of the exchanger (26); - comparing said estimated mass (M_water) with a limit value (S); and - activating the purge of the cooler (26) when the estimated mass of water (M_water) is greater than the limit value (S), generating oscillations in the intake air flow rate (Qaf) entering the exchanger (26) between a nominal flow rate value (Qaf_name) and an increased flow rate value (Qaf_+) and oscillations in the ignition advance (AV) between a nominal advance value (AV_name) and a degraded advance value (AV_-).

2. Method according to claim 1, CHARACTERIZED in that the oscillations of the intake air flow Qaf are obtained by controlling the opening of the adjustment valve (24) by performing oscillations between a nominal position %BP_name corresponding to an engine operating point and an additional opening position %BP_+. Petition 870250088325, dated 09 / 29 / 2025, p. 23 / 28 2 / 3 3. Method, according to claim 1 or 2, CHARACTERIZED in that the generation of oscillations of the intake air flow rate Qaf entering the heat exchanger 26 and the generation of oscillations of the ignition timing advance AV are carried out simultaneously.

4. Method, according to any of the preceding claims, CHARACTERIZED in that the oscillations of the intake air flow form oscillating steps between the nominal flow value (Qaf_name) and the increased flow value (Qaf_+), and the generation of the ignition timing advance oscillations forms oscillating steps between the degraded advance value (AV_-) and the nominal advance value (AV_name), the nominal value of the ignition timing advance corresponding to the nominal position of the intake air flow (Qaf_name) and, in particular, of the adjustment valve or throttle body (24).

5. Method, according to claim 4, CHARACTERIZED in that the grooves have an identical time period (τ) between the ascending and descending phases, for example, between 1 and 2 s, for example, equal to 1.5 s.

6. Method, according to claim 4 or 5, CHARACTERIZED in that the purge step has a duration (δθ) required to evacuate the water from the cooler (26) between 8 and 12 s, preferably equal to 10 s.

7. Electronic control unit (ECU) of a spark-ignition internal combustion engine (10) comprising at least one cylinder (12), a fresh air intake manifold (14) supplied with fresh air through a duct (20), a compressor (18b) of a turbocharger (18) and a heat exchanger (26) downstream of said compressor (18b) and upstream of the intake manifold (14), the engine further comprising an exhaust circuit (Ce) comprising, from upstream to downstream in the direction of the flow of the burned gases, an exhaust manifold (16), a turbine (18a) of the turbocharger (18) and a partial recirculation circuit of the exhaust gases (50) in the intake, originating at a point in the exhaust circuit (Ce) Petition 870250088325, dated 29 / 09 / 2025, page. 24 / 28 3 / 3 downstream of said turbine (18a) and opening into the fresh air supply duct (20) upstream of the compressor (18b) of the turbocharger (18),the said intake circuit (Ca) comprising an adjustment valve (24) mounted between the compressor (18b) and the heat exchanger (26), the electronic control unit (ECU), CHARACTERIZED in that it comprises an engine control system (70) comprising: - a module (71) for estimating the mass (M_water) of liquid water stored in real time on the inner walls of the heat exchanger (26); - a module (72) for comparing the estimated mass of water (M_water) with a limit value (S); and - a module (74) to activate the purge of the heat exchanger (26) when the estimated mass of water (M_water) is greater than the limit value (S), the module being configured to generate oscillations of the intake air flow rate (Qaf) entering the heat exchanger (26) between a nominal flow rate value (Qaf_name) and an increased flow rate value (Qaf_+), and oscillations of the ignition timing advance (AV) between a nominal advance value (AV_name) and a degraded advance value (AV_-).

8. Electronic control unit (ECU), according to claim 7, CHARACTERIZED in that the module for activating the purge (74) of the heat exchanger (26) comprises a module for controlling (76) the adjustment valve (24), performing oscillations between a nominal position (%BP_name) corresponding to an engine operating point and an additional opening position (%BP_+).

9. Electronic control unit (ECU), according to claim 7 or 8, CHARACTERIZED in that the module for activating the purge (74) of the heat exchanger (26) comprises a module for modulating (78) the ignition timing advance, configured to modulate the ignition timing advance between the nominal advance value (AV_name) and a degraded advance value (AV_-).

10. Motor vehicle, CHARACTERIZED in that it comprises an electronic control unit according to any one of claims 7 to 9. Petition 870250088325, dated 09 / 29 / 2025, pp. 25 / 28

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