Spark Ignition Engine System and Related Implementation Method

Abstract

The present invention relates to an ignition engine system (1), and the ignition system comprises an internal combustion engine (2), an electric water pump configured to be coupled to the internal combustion engine (2), an electric motor configured to drive the electric water pump, a computer configured to control the speed of the electric water pump to adjust the water flow rate of the electric water pump by applying a water flow rate setting value to the electric motor, an air intake circuit (2) and an exhaust circuit (15) associated with the internal combustion engine (2), and a fuel supply circuit for the internal combustion engine (2), wherein the internal combustion engine (2) is equipped with at least one knock sensor (11) and the air intake circuit (2) is equipped with an intake manifold (10) equipped with a sensor for the intake gas temperature (Tcol), and the computer is configured to apply control logic for the water pump, wherein a preventive knock correction factor of 1 or more is applied to the water flow rate setting value according to the temperature of the coolant of the internal combustion engine (2) and the temperature of the intake gas (Tcol); and a method is for implementing the system (1).

Description

Technology Field

[0001] The present invention relates to a vehicle equipped with a spark ignition internal combustion engine having an electric coolant pump.

[0002] This type of electric water pump gradually replaces conventional mechanical water pumps in automobiles, reducing engine fuel consumption and consequently carbon dioxide emissions.

[0003] In conventional mechanical water pumps, the pump impeller shaft is driven directly by the engine crankshaft via an accessory belt, so the pump's rotational speed, and thus the pump's flow rate, depends only on the engine speed.

[0004] In the case of an electric water pump, the shaft of the pump wheel is driven by an electric motor supplied with a low voltage, typically 12V or 48V, depending on the type of battery available in the vehicle.

[0005] The engine control computer controls the water flow rate according to the speed of the water pump, which is a parameter for reducing or eliminating knocking that may occur in spark ignition engines.

[0006] The object of the present invention is to provide a spark ignition engine system that minimizes fuel consumption by taking into account the possible occurrence of knocking that degrades engine performance. This also relates to a method for implementing such a system. Background Technology

[0007] For example, a spark ignition engine is known from document EP2140122B1, which discloses a variable compression ratio engine equipped with a knock sensor and an electric water pump. In the event of knocking, the engine computer increases the rotational speed of the pump to increase the flow rate of coolant supplied to the area near the surface of the combustion chamber and reduces the compression ratio of the engine.

[0008] Therefore, this document discloses the principle of increasing the flow rate of a water pump in a healing manner in response to knocking, but does not disclose any preventive treatment for the knocking phenomenon or the use of a correction factor for the flow rate of the water pump.

[0009] Because it is necessary to reduce the ignition advance to eliminate this knocking, and because it is necessary to consider possible knocking phenomena that limit the performance of the internal combustion engine and reduce consumption, known control logic intended to therapeutically increase the flow rate of the water pump in response to knocking is insufficient to minimize consumption and maximize the performance of the spark ignition engine system in all usage cases.

[0010] However, increasing the water flow rate beyond what is strictly necessary to prevent overheating makes it possible to increase the heat exchange coefficient and significantly reduce knocking due to more effective cooling of the walls of the combustion chamber.

[0011] Taking the foregoing into consideration, the objective of the present invention is to propose an electric water pump control logic that overcomes at least some of the aforementioned disadvantages and enables consideration of such knocking components and the consumption and performance of the motor.

[0012] Considering the above, the subject of the present invention is a spark ignition engine system, and the spark ignition engine system comprises an internal combustion engine, an electric water pump configured to be coupled to the internal combustion engine, an electric motor configured to drive the electric water pump, a computer configured to control the speed of the electric water pump to control the water flow rate of the electric water pump by controlling the electric motor through a water flow rate setting value, an air intake circuit and an exhaust circuit associated with the internal combustion engine, and a fuel supply circuit for the internal combustion engine, wherein the internal combustion engine is equipped with at least one knock sensor, the air intake circuit is equipped with an intake manifold equipped with an intake gas temperature sensor, and the computer is configured to apply a control logic for the water pump in which a preventive knock correction factor of 1 or more is applied to the water flow rate setting value as a function of the coolant temperature of the internal combustion engine and the temperature of the intake gas.

[0013] Preferably, the computer is further configured to apply control logic for a water pump by taking into account the knock measured by the knock sensor through the application of a correction factor of 1 or more applied to a water flow rate setting value according to the knock level calculated by the computer from the knock sensor located on the internal combustion engine.

[0014] For example, the water flow rate setting value is limited to a threshold value that is less than or equal to the maximum water flow rate achievable by the electric water pump.

[0015] Advantageously, the air intake circuit further comprises: an air filter, a fresh air temperature sensor, a compressor, a supercharged air cooler supplied by the first compressor, and an air intake valve of the intake manifold of the internal combustion engine in the direction of air circulation from upstream to downstream to the internal combustion engine.

[0016] According to one embodiment, the exhaust circuit includes an exhaust manifold, a turbine, and an assembly for decontaminating the combustion gas from an internal combustion engine in the direction of flow of combustion gas from an internal combustion engine from upstream to downstream.

[0017] In one embodiment, an assembly for decontaminating combustion gases from an internal combustion engine includes a three-way catalyst and / or a particulate filter.

[0018] Advantageously, the system includes a turbocharger comprising both a compressor and a turbine, and the internal combustion engine is an inline 3-cylinder engine of the type supercharged by said turbocharger.

[0019] The present invention also relates to a method for implementing a system as defined above, the method comprising: a first step in which a computer applies a mapping of the water flow rate of an electric water pump as a function of the speed and current torque of an internal combustion engine to correct the water flow rate to a water flow rate required to satisfy the cooling needs of the internal combustion engine; a second step in which a modulation coefficient to be applied to the water flow rate is calculated as a function of the temperature of the coolant of the internal combustion engine, performed simultaneously with the first step; a third step in which a water flow rate set value is obtained by multiplying the modulation coefficient calculated during the second step by the water flow rate calculated during the first step; a fourth step in which a computer configured to control the speed of the electric water pump applies the water flow rate set value to an electric motor, followed by a fifth step in which the electric water pump is activated at the water flow rate set value, wherein the method further comprises a sixth step in which a preventive knock correction factor of 1 or more is determined to be applied to the water flow rate set value as a function of the temperature of the coolant of the internal combustion engine and the temperature of the intake gas, and following the sixth step, the preventive correction factor is calculated during the third step The ninth step of multiplying by the water flow rate setting value follows, and the sixth step continues to the fourth step.

[0020] Preferably, the method further comprises a seventh step in which a healing factor is determined as a function of a knock level calculated by a computer from a knock sensor, and the seventh step is followed by an eighth step in which a preventive correction factor is multiplied by the healing correction factor, the eighth step continues to a ninth step, and the ninth step comprises an additional multiplication of this result by a water flow rate setting value.

[0021] The present invention also relates to a method for implementing a system as defined above, and the method further comprises a tenth step after the ninth step in which a water flow rate setting value calculated during the ninth step is compared with a threshold value, and subsequently the method is interrupted if the threshold value exceeds the water flow rate setting value, or the method continues to the fourth step if the water flow rate setting value is less than the threshold value. Brief explanation of the drawing

[0022] The present invention will be better understood by detailed consideration of embodiments taken as non-limiting examples and illustrated by the accompanying drawings: [Fig. 1] is a drawing showing the general architecture of a spark ignition engine system in terms of the air intake and exhaust systems. [Fig. 2] is a diagram showing the engine coolant circuit. [Fig. 3] is a diagram showing the steps of the control logic of a motor cooling pump according to the prior art. [Fig. 4] is a diagram showing the mapping of the water flow rate of an electric water pump as a function of the current speed and rotational force of an internal combustion engine to correct the water flow rate. [Fig. 5] is a diagram showing a control table applied to the water flow rate setting value. [Fig. 6] is a diagram showing the steps of the control logic of an engine cooling pump according to the method of the present invention. [Fig. 7] is a diagram showing the mapping of preventive correction factors applied to a water flow rate set value according to the present invention. [Fig. 8] is a diagram showing a table of healing correction factors applied to a water flow rate setting value according to the present invention. Specific details for implementing the invention

[0023] FIG. 1 illustrates a part of a spark ignition engine system (1) according to the present invention, more specifically, a general architecture of the air intake and exhaust circuits of a spark ignition engine system.

[0024] The system (1) includes an air intake (3) and a gas outlet (4), an internal combustion engine (2), an electric water pump (20) configured to be coupled to the internal combustion engine (2), and an electric motor (23) configured to drive the electric water pump (20) as illustrated in FIG. 2.

[0025] The electric motor (23) is supplied with a low voltage, typically 12V or 48V, depending on the type of battery available in the vehicle, for example.

[0026] The system (1) further includes a computer (not shown), of the type of engine control computer, configured to control the speed of the electric water pump (20) so as to control the water flow rate (Qeau) of the electric water pump (20) by controlling the electric motor (23) by the water flow rate setting value (Qeau_cons).

[0027] The system (1) further includes an air intake circuit (3) and an exhaust circuit (15) associated with an internal combustion engine (2).

[0028] The system (1) additionally includes a fuel supply circuit for an internal combustion engine (2) (not shown).

[0029] The internal combustion engine (2) is equipped with at least one knock sensor (11) on the internal combustion engine (2).

[0030] The knock sensor is located, for example, on the crankcase of the internal combustion engine (2).

[0031] The air intake circuit (3) includes an intake manifold (10) equipped with a sensor for the temperature of the intake gas (Tcol).

[0032] The computer is configured to apply control logic for a water pump (20), wherein a preventive knock correction factor of 1 or more is applied to a water flow rate setting value (Qeau_cons) as a function of the coolant temperature (Tco) and intake gas temperature (Tcol) of the internal combustion engine (2).

[0033] Accordingly, the spark ignition engine system (1) makes it possible to apply electric water pump control to optimize fuel consumption and maximize engine performance in various usage scenarios by reducing or eliminating knocking without requiring a reduction in ignition advance, and by increasing the target water flow rate for more efficient cooling of the combustion chamber walls.

[0034] Advantageously, the system (1) further comprises an air supply circuit for an internal combustion engine (2) including, for example, a butterfly valve in the intake manifold (10) of the internal combustion engine (2), in the direction of air circulation from upstream to downstream to the internal combustion engine (2): an air filter (12), a fresh air temperature sensor placed on the outlet (13) of the air filter (12), a compressor (5), a supercharged air cooler (8) supplied by the first compressor (5), an air intake valve (9), and a butterfly valve in the intake manifold (10) of the internal combustion engine (2).

[0035] The system (1) includes a fuel supply unit for an internal combustion engine (2), which includes a fuel injector for injecting fuel directly, for example, into the combustion chamber of the engine.

[0036] The internal combustion engine (2) is cooled by a cooling circuit (16) illustrated in FIG. 2, which includes a coolant temperature sensor (Tco), an electric water pump (20), and, for example, a radiator (18) which is an air / water type exchanger.

[0037] The radiator (19) receives fresh air passing through the radiator from the air inlet (17), as well as hot water reaching the inlet (21) from the electric water pump (20) and the internal combustion engine (2) according to the water flow rate (Qeau), cools the water by the outlet (19), and then returns this water to the internal combustion engine (2).

[0038] The electric water pump (20) can force the flow circulation of cooling liquid from the internal combustion engine (2) to the pump and discharge this flow to a radiator where the liquid is cooled.

[0039] In this description, the term "water" is used to refer to this coolant uniformly.

[0040] Next, the liquid is returned to the internal combustion engine (2).

[0041] In a manner known in itself, the circuit can adjust the coolant temperature (Tco) to a set value.

[0042] An assembly (24) for decontaminating combustion gases from an internal combustion engine (2) may include a particulate filter (6) and / or a three-way catalyst (7).

[0043] In addition, the internal combustion engine (2) includes an exhaust circuit (15).

[0044] The exhaust circuit (15) is illustrated more specifically in FIG. 2 and includes an exhaust manifold, a turbine (14), and a decontamination assembly (24) for the combustion gas from the internal combustion engine (2) that forms the exhaust circuit (15) from upstream to downstream in the direction of flow of combustion gas from the internal combustion engine (2).

[0045] The turbine (14) is mounted on a shaft that is common to, for example, the compressor (5).

[0046] Advantageously, the system (1) includes a turbocharger comprising both a compressor (5) and a turbine (14), and the internal combustion engine (2) is an inline 3-cylinder engine of the type supercharged by the turbocharger.

[0047] Preferably, the computer is further configured to apply control logic for the water pump (20) by taking into account the knock measured by the knock sensor (11) by applying a healing correction factor of 1 or more as a water flow rate setting value (Qeau_cons) according to the knock level (Knk) calculated by the computer from the knock sensor (11) located on the internal combustion engine (2).

[0048] For example, the water flow rate setting value (Qeau_cons) is limited to a threshold value (Qmax) that is less than or equal to the maximum water flow rate (Qeau) achievable by the electric water pump (20).

[0049] For example, Qmax is about 5 m³ per hour.

[0050] The present invention also relates to a method for implementing the system (1) as described above.

[0051] As with the method of the prior art exemplified in FIG. 3, the method includes the steps described below.

[0052] The method begins with a first step (E1) in which a computer applies a mapping of the water flow rate of an electric water pump (20) as a function of the speed and current rotational force of the internal combustion engine (2) to correct the water flow rate (Qeau) to meet the cooling needs of the internal combustion engine (2).

[0053] Therefore, the "basic" water flow rate setpoint (Qeau) is determined by a two-dimensional mapping according to engine speed and torque, and then adjusted by a factor according to the coolant temperature (Tco) measured by the water temperature sensor to reach the final water flow rate setpoint (Qeau_cons).

[0054] Then, these water flow rate setting values ​​(Qeau_cons) are converted into electrical commands to the electric water pump (20) through the pump control computer.

[0055] As in the method according to the prior art, the method uses a mapping (T1) such as illustrated in FIG. 4, which maps the water flow rate (Qeau) of an electric water pump (20) as a function of the current speed and rotational force of an internal combustion engine to correct the water flow rate (Qeau).

[0056] Figure 4 shows the mapping (T1) of the calibration generally adopted for pump control.

[0057] The basic water flow rate mapping is corrected as needed under high-temperature engine conditions, that is, when the temperature (Tco) reaches at least a given threshold value, for example, 90°C, and there is no overheating of the internal combustion engine (2).

[0058] The water flow requirement (Qeau) increases further as speed and rotational force increase, as the calorific value introduced by the fuel increases.

[0059] According to the maps (T1 and T2) illustrated in FIGS. 4 and 5, since the battery supplying the electric water pump (20) is recharged by an alternator mechanically driven by an internal combustion engine (2), the electric water pump (20) can provide up to 5.5 m³ per hour, so as to limit electricity consumption and thus fuel consumption, the requested maximum value is 3.5 m³ per hour.

[0060] The method includes a second step (E2) which is performed simultaneously with the first step (E1) and in which a control coefficient to be applied to the water flow rate (Qeau) according to the coolant temperature (Tco) of the internal combustion engine is calculated from a control table (T2) such as that illustrated in FIG. 5, for example, through a table (T2) such as that illustrated in FIG. 5.

[0061] The control table (T5) is calibrated so that the water flow rate (Qeau) is very low, i.e., almost zero, as long as the internal combustion engine (2) does not exceed, for example, a water temperature of 50°C, so that the internal combustion engine (2) is heated as quickly as possible, which generates a control table (T5) with a coefficient of 1 / 10.

[0062] Therefore, the basic water flow rate (Qeau) is limited to 10% of its value, which makes it possible to reduce the consumption disadvantage associated with higher engine friction when the internal combustion engine (2) is not hot.

[0063] When the temperature of the internal combustion engine (2) reaches a threshold of 90°C, there is no further control, that is, the control coefficient is 1.

[0064] In the meantime, the coefficient must be an increasing function of temperature.

[0065] The method also includes a third step (E3) of obtaining a water flow rate set value (Qeau_cons) by multiplying the control coefficient calculated during the second step (E2) by the water flow rate (Qeau) calculated during the first step (E1).

[0066] The third step (E3) continues to the fourth step (E4), in which a computer, for example, coupled to the control module of the pump (22) and configured to control the speed of the electric water pump (20), applies a water flow rate setting value (Qeau_cons) to the electric motor (23).

[0067] Following the fourth step, the fifth step (E5) follows, in which the electric water pump (20) is activated by the electric motor (23) at the water flow rate setting value (Qeau_cons).

[0068] Unlike conventional technology, the method further includes a sixth step (E6) preceding the fourth step (E4) in which a preventive knock correction factor of 1 or more is determined to be applied to the water flow rate setting value (Qeau_cons) as a function of the coolant temperature (Tco) and intake gas temperature (Tcol) of the internal combustion engine (2), followed by a ninth step (E9) in which the preventive correction factor is multiplied by the water flow rate setting value (Qeau_cons) calculated during the third step (E3), and the sixth step (E6) continues to the fourth step (E4).

[0069] This method makes it possible to reduce or even eliminate knocking when necessary without significant additional cost by increasing the water flow rate (Qeau) of the electric water pump (20), so that it is not necessary to reduce the ignition advance that lowers the efficiency and performance of the internal combustion engine (2).

[0070] Since this effect is very pronounced at low speeds, the increase in electric consumption associated with the increased flow rate (Qeau) on the side of the electric water pump (20) is largely offset by the lower fuel consumption on the side of the internal combustion engine (2) because there is no need to respond to knocking by lowering the ignition advance.

[0071] For example, the preventive knock correction factor is determined in step (E6) by the correction table (T3) as exemplified in FIG. 7.

[0072] The knocking phenomenon is more likely to occur when the temperature of the combustion chamber of the internal combustion engine (2) is high, and this is transferred by the coolant temperature (Tco) and the intake gas temperature (Tcol) measured by the temperature sensor of the manifold (10).

[0073] The control logic of the water pump (20) managed by the computer takes into account the knocking phenomenon by integrating one or two corrections for the water flow rate, namely, a preventive correction and optionally a healing correction.

[0074] If preventive correction is accurately calibrated, curative correction is not necessary, but it can be advantageously applied to account for other factors adverse to knocking, such as fuel with a very low octane rating, in order to calibrate the engine at rated output.

[0075] Due to healing correction, an additional increase in water flow (Qeau) makes it possible to handle this knocking case.

[0076] Preventive correction is performed in the form of a factor greater than or equal to 1 depending on the water temperature (Tco) and the intake gas temperature (Tcol).

[0077] For hot outdoor conditions with hot water temperature (Tco) and / or gas temperature (Tcol), for example, a gas temperature (Tcol) of the intake manifold inlet of about 80°C, knocking is present, and increasing the water flow rate relative to the basic flow rate reduces or even eliminates the knocking.

[0078] This preventive correction occurs at the nominal correction conditions of the internal combustion engine (2) on the engine bench, namely, a coolant temperature (Tco) of about 90°C and an intake gas temperature (Tcol) of about 40°C, and an intake fresh air temperature of about 25°C.

[0079] The method may further include a seventh step (E7) in which a healing factor is determined as a function of a knock level (Knk) calculated by a computer from a knock sensor (11). Following the seventh step (E7), an eighth step (E8) is followed in which a preventive correction factor is multiplied by the healing correction factor.

[0080] During the following 9th step (E9), the result of step (E8) is multiplied by the water flow rate setting value (Qeau_cons).

[0081] Next, the method returns to step 4 (E4).

[0082] The method may further include a tenth step (E10) following the ninth step (E9), which compares the water flow rate set value (Qeau_cons) calculated during the ninth step (E9) with a threshold value (Qmax).

[0083] The method is stopped when the water flow rate setting value (Qeau_cons) exceeds the threshold value (Qmax).

[0084] The method continues to step 4 (E4) if the above water flow rate setting value (Qeau_cons) is less than the above threshold value (Qmax).

Claims

Claim 1 A spark ignition engine system (1) comprises an internal combustion engine (2), an electric water pump (20) configured to be coupled to the internal combustion engine (2), an electric motor (23) configured to drive the electric water pump (20), a computer configured to control the speed of the electric water pump (20) to control the water flow rate (Qeau) of the electric water pump (20) by controlling the electric motor (23) by a water flow rate setting value (Qeau_cons), an air intake circuit (2) and an exhaust circuit (15) associated with the internal combustion engine (2), and a fuel supply circuit for the internal combustion engine (2), wherein the internal combustion engine (2) is equipped with at least one knock sensor (11) and the air intake circuit (2) is equipped with an intake manifold (10) having an intake gas temperature (Tcol) sensor, and the system (1) comprises, wherein the computer has a preventive knock correction factor of 1 or more for the coolant of the internal combustion engine (2). A spark ignition engine system (1) characterized by being configured to apply control logic of the water pump (20) to the water flow rate setting value (Qeau_cons) as a function of temperature (Tco) and intake gas temperature (Tcol). Claim 2 A spark ignition engine system (1) according to claim 1, wherein the computer is additionally configured to apply control logic of the water pump (20) by applying a healing correction factor of 1 or more applied to the water flow rate setting value (Qeau_cons) as a function of the knock level (Knk) calculated by the computer from the knock sensor (11) located on the internal combustion engine (2). Claim 3 In paragraph 2, the spark ignition engine system (1) is limited to a threshold value (Qmax) that is less than or equal to the maximum water flow rate (Qeau) achievable by the electric water pump (20). Claim 4 In any one of claims 1 to 3, the air intake circuit (3) further comprises: an air filter (12), a fresh air temperature sensor, a compressor (5), a supercharged air cooler (8) supplied by the first compressor (5), and an air intake valve (9) of the intake manifold (10) of the internal combustion engine (2) in the direction of air flow from upstream to downstream, a spark ignition engine system (1). Claim 5 In paragraph 4, the exhaust circuit (15) comprises: an exhaust manifold (15), a turbine (14), and a decontamination assembly (24) for the combustion gas from the internal combustion engine (2) in the direction of flow of the gas combusted from the internal combustion engine (2) from upstream to downstream, a spark ignition engine system (1). Claim 6 In paragraph 5, the exhaust gas decontamination assembly (24) from the internal combustion engine (2) comprises a particulate filter (6) and / or a three-way catalyst (7), in a spark ignition engine system (1). Claim 7 A spark ignition engine system (1) according to claim 5 or 6, further comprising a turbocharger including both the compressor (5) and the turbine (14), wherein the internal combustion engine (2) is an inline 3-cylinder engine of the type supercharged by the turbocharger. Claim 8 A method for implementing a system (1) according to any one of claims 1 to 8, comprising: a first step (E1) in which the computer applies a mapping (T1) of the water flow rate of the electric water pump (20) as a function of the current speed and rotational force of the internal combustion engine (2) to correct the water flow rate (Qeau) to a water flow rate required to satisfy the cooling needs of the internal combustion engine (2); a second step (E2) in which a modulation coefficient to be applied to the water flow rate (Qeau) as a function of the cooling water temperature (Tco) of the internal combustion engine is calculated from a control table (T2) and the modulation coefficient calculated during the second step (E2) is multiplied by the water flow rate (Qeau) calculated during the first step (E1) to obtain a water flow rate setting value (Qeau_cons); and the computer configured to control the speed of the electric water pump (20) obtains the water flow rate setting value (Qeau_cons). A method comprising a fourth step (E4) applied to the electric motor (23), followed by a fifth step (E5) in which the electric water pump (20) is activated at the water flow rate setting value (Qeau_cons), wherein the method further comprises a sixth step (E6) preceding the fourth step (E4) in which a preventive knock correction factor of 1 or more to be applied to the water flow rate setting value (Qeau_cons) is determined as a function of the coolant temperature (Tco) of the internal combustion engine (2) and the intake gas temperature (Tcol), and a ninth step (E9) followed by the sixth step (E6) in which the preventive correction factor is multiplied by the water flow rate setting value (Qeau_cons) calculated during the third step (E3), and the sixth step (E6) continues to the fourth step (E4). Claim 9 A method according to claim 8 for implementing a system (1) according to any one of claims 2 and 3 through 7, further comprising a seventh step (E7) in which a healing factor is determined as a function of the knock level (Knk) calculated by the computer from the knock sensor (11), followed by an eighth step (E8) in which the prevention correction factor is multiplied by the healing correction factor, the eighth step (E8) continues to the ninth step (E9), and the ninth step (E9) comprises additional multiplication of this result by the water flow rate setting value (Qeau_cons). Claim 10 A method according to claim 8 or 9 for implementing a system (1) according to claim 3, further comprising a 10th step (E10) after the 9th step (E9) in which the water flow rate setting value (Qeau_cons) calculated during the 9th step (E9) is compared with the threshold value (Qmax), wherein the method is interrupted when the water flow rate setting value (Qeau_cons) exceeds the threshold value (Qmax), or wherein the method continues to the 4th step (E4) when the water flow rate setting value (Qeau_cons) is less than the threshold value (Qmax).

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