Automotive alternator management method and system

Abstract

A method and management system for an automotive alternator in a vehicle with an internal combustion engine (ICE) is described, wherein the alternator (1) is controlled by an ECU (23), which is capable of facilitating mechanical coupling of the alternator (1) with a toothed belt (5) and electrical coupling of the alternator (1) with a battery (20), and the ECU (23) receives a signal from a battery charge sensor (22) to determine a battery charge level between BC1 (corresponding to a fully charged state), BC2 (corresponding to a serviceable charge level), and BC3 (corresponding to a low charge level). and acting on the alternator so that at level BC1, the alternator (1) is maintained in an electrically and mechanically decoupled state, at level BC3, the alternator (1) is maintained in an electrically and mechanically coupled state, and at level BC2, the alternator (1) is mechanically coupled when the vehicle's travel speed is greater than a given value (VLim) and when the engine (ICE) is disengaged for a gear change, and the alternator (1) is electrically connected when the vehicle is driven in cutoff mode.

Description

[Technical Field]

[0001] The present invention relates to a method and system for managing an alternator for a motor vehicle, and more particularly to a method for managing an alternator that may be electrically and / or mechanically coupled and decoupled to an internal combustion engine (ICE) or the like. More particularly, the present invention is intended to manage the selective coupling or decoupling of the alternator depending on the state of the battery in combination with the operating conditions of the vehicle. [Background technology]

[0002] Systems known in the art for generating electrical energy for vehicles typically include an electric machine, driven by the vehicle's engine via a synchronous belt at the moment of ignition, responsible for generating electrical energy. The alternator powers all electrical devices and charges the battery while the vehicle is in operation, and is named after the type of electrical current it generates. This device works according to the principle of electromagnetic induction: when current flows through the rotor, a magnetic field is generated, which induces the movement of electrons in the stator coils, generating an alternating current. Because automobiles operate on direct current, automotive alternators also include two basic components: a rectifier (or simply a rectifier), which converts alternating current to direct current, and a voltage regulator, which controls the voltage generated.

[0003] However, despite their widespread use in vehicles, these electric machines consume mechanical energy from the crankshaft, thereby contributing to fuel consumption and carbon dioxide (CO2) emissions. Because the engine's mechanical energy is derived from thermal energy from the combustion of fuel, the alternator represents a load on the system, increasing fuel consumption to compensate for the energy used by the alternator when charging the battery. Furthermore, even when the battery is at a sufficient charge level, the alternator continues to consume mechanical energy from the crankshaft to power the vehicle systems. Vehicle systems are becoming more complex and therefore consuming more electrical energy.

[0004] Fuel consumption and carbon dioxide emissions directly represent indicators that constitute the determination of a vehicle's energy efficiency level. The combustion of fuels, especially fossil fuels, generates high concentrations of carbon dioxide (CO2) through combustion. High concentrations of carbon dioxide released into the atmosphere promote adverse environmental effects, such as the greenhouse effect and the resulting global warming, and therefore imply the possibility of natural disasters (e.g., tsunamis) and climate change, which widely affects daily life. Furthermore, fuel consumption is associated with the emission of carbon monoxide (CO) and hydrocarbons (HC), which have been proven to be harmful to human health.

[0005] Several techniques have been devised and implemented to minimize the negative impact of alternators on vehicle fuel consumption. These efforts are usually based on improving the alternator's efficiency (electrical or mechanical) and the possibility of strategically operating it according to the battery's electrical energy demands. Recent developments include so-called "intelligent alternators" (IAs), which are designed to minimize the alternator's mechanical load on the crankshaft based on data collected by the alternator from the vehicle itself (e.g., the ECU). Among alternators with internal control systems, those described in German Patent Application Publication No. DE 19638872 and U.S. Patent No. 7,816,893 are particularly well-known, which describe measures for electrically disconnecting the alternator from the vehicle's electrical load under certain conditions. This electrical disconnection occurs, in particular, when the battery has a sufficient charge level to supply the vehicle's electrical system or when the alternator's operating condition is insufficient. Electrical reconnection occurs when the battery reaches a minimum charge level and requires recharging. In this way, the mechanical load on the crankshaft is minimized during the period of electrical disconnection of the alternator.

[0006] The invention described in U.S. Patent No. 10,247,265, made by the present inventor, relates to an alternator (E / MS) that can be coupled to and / or disengaged from the crankshaft of a vehicle engine (such as an ICE), with the coupling or mechanical disengagement being selectively performed in a separate step from the electrical connection or disconnection. Advantages of the described alternator include reduced fuel consumption and therefore reduced emissions by the vehicle engine, as well as reduced jolts that occur when electrical and mechanical coupling occurs.

[0007] Thus, despite the benefits arising from the use of both the intelligent alternator described above and alternators having unique electrical and mechanical couplings, further research has led to the development of new management strategies for vehicle alternators that can further enhance such benefits. Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, a first object of the present invention is a method for managing an alternator that can be coupled to or decoupled from the crankshaft of a vehicle engine, thereby reducing the load on the crankshaft and, as a result, significantly reducing jolts and, in addition, fuel consumption, carbon dioxide (CO2) emissions, as well as carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NO x ) and other polluting gas emissions.

[0009] Another object of the present invention is to provide a method for managing an alternator designed to facilitate selective coupling and disengagement of the alternator depending on the battery charge level and, in combination therewith, depending on the vehicle's operating mode. [Means for solving the problem]

[0010] These and other objects are provided by a method for managing an alternator for a motor vehicle, the method comprising: - determining a battery charge level between BC1 (corresponding to a fully charged state of the battery), BC2 (corresponding to a practical battery charge level) and BC3 (corresponding to a low battery charge level); - at level BC1, the alternator is kept electrically and mechanically disconnected; - at level BC3, the alternator remains electrically and mechanically coupled, and At level BC2, the alternator is mechanically coupled when the vehicle's speed is greater than a given VLim value and when the ICE engine is disengaged for a gear change, and the alternator is electrically connected when the vehicle is driven in cutoff mode.

[0011] The method further includes the step of mechanically and electrically disengaging the alternator when the engine speed is below a given limit value RLim.

[0012] Likewise, an object of the present invention is an alternator management system for a motor vehicle including a vehicle with an ICE engine, wherein rotation of a crankshaft is transmitted to said alternator via a toothed belt, said vehicle further comprising a battery for supplying an electrical system of the vehicle, and a battery charge sensor, said alternator being controlled by an ECU, said ECU being able to facilitate mechanical coupling of said toothed belt with said alternator by acting on a pulley, and being able to facilitate electrical coupling with said battery, said ECU receiving a signal from said battery charge sensor and - determining the battery charge level between BC1 (corresponding to a fully charged state of the battery), BC2 (corresponding to a practical battery charge level) and BC3 (corresponding to a low battery charge level); to said alternator, - at level BC1, the alternator is maintained in an electrically and mechanically disengaged state; - At level BC3, the alternator remains electrically and mechanically coupled, and At level BC2, it is also achieved and fulfilled by a motor vehicle alternator management system that acts to mechanically couple the alternator when the vehicle's speed is greater than a given VLim value and when the ICE engine is disengaged for a gear change, and to electrically couple the alternator when the vehicle is driven in cutoff mode.

[0013] Furthermore, the system also includes mechanically and electrically disengaging the alternator when the engine speed is below a given limit value RLim. The present invention will be better understood from the detailed description of preferred embodiments thereof, supported and illustrated by the accompanying drawings, which are presented merely for purposes of illustration and guidance, and are not intended to limit the scope of the invention. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 2 is a schematic diagram of the mechanical connection between the alternator pulley and the crankshaft pulley. [Figure 2] FIG. 1 is a schematic diagram of an alternator power supply and control system. [Figure 3] 1 is a chart showing operating parameters of an ICE as a function of driving time for a vehicle with a manual transmission and also showing opportunities to charge the battery. [Figure 4] 1 is a chart showing operating parameters of an ICE as a function of driving time for a vehicle with an automatic or automated transmission, and also showing opportunities to charge the battery. DETAILED DESCRIPTION OF THE INVENTION

[0015] 1 and 2, numeral 1 designates an alternator including, in a known manner, a housing 2, inside which a rotor (not shown) and a stator (not shown) are housed, the relative rotational movement of which results in the generation of an electromagnetic field for the production of electrical energy. In particular, alternator 1 is an alternator with a selective mechanical coupling and electrical connection system (E / MC) (according to U.S. Pat. No. 10,247,265). Broadly speaking, alternator 1 is an alternator that can be coupled and / or decoupled to a vehicle's drive system and electrically connected / disconnected to the vehicle's electrical system, independently of one another. In particular, as will be apparent to those skilled in the art, the advantages of this alternator are realized when the mechanical coupling precedes the electrical connection.

[0016] While the stator is fixedly mounted relative to the frame 2, the rotor occupies a central position in the alternator 1, protruding beyond the space enclosed by the frame 2 and rotatably supported about an axis 3 intended to receive, via a pulley 4, the torque necessary to provide relative rotational movement between the rotor and the stator. As is also known, a belt 5, typically a toothed belt, engages both the pulley 4 and a pulley 6 of a crankshaft 7. As is also known, the belt 5 may engage other mechanical devices, such as, for example, a tensioner 8 intended to keep the belt 5 tensioned within specific usage parameters and a guide pulley such as an idler pulley (not shown). Similarly, the pulley 6 of the crankshaft 7 is also responsible for driving other devices of the vehicle, such as, for example, a power steering pump pulley 28 or an air conditioning system pulley 9, via a belt 29.

[0017] Regarding the electrical connections of the system (see FIG. 2), the alternator 1 is electrically connected in parallel with the battery 20, both of which are connected to power the vehicle's electrical loads 21, such as the air conditioning system, radio, interior and exterior lights, etc.

[0018] In one embodiment, the battery 20 is further connected to a battery state-of-charge sensor 22 capable of assessing the electrical charge stored in the battery cells and providing a signal indicative of this charge to a control unit or ECU 23 via data line 24.

[0019] Generally speaking, the charge of the battery 20 is determined by a system and / or device that determines or detects the charge of the battery. By way of example, but not limitation, the detection or determination of the charge level of the battery 20 may be performed from a device or system such as those described in the applicant's document WO 2017 / 027950 or documents U.S. Pat. No. 8,536,872 or U.S. Pat. No. 6,674,266, among others.

[0020] For the particular case in which alternator 1 is an alternator (E / MC) according to U.S. Pat. No. 10,247,265, the mechanical coupling between shaft 3 and pulley 4 is performed and mediated by an electromagnetic clutch 10, which is able to couple and discouple shaft 3 relative to pulley 4. In this case, ECU 23 is further connected to alternator 1 via data line 25A and to clutch 10 via data line 25B, and is able to command the electrical behavior (engagement or disengagement) of alternator 1 and the mechanical behavior of pulley 4, respectively. More specifically, alternator 1, in addition to its electrical connections with battery 20 and the vehicle's electrical loads 21, also includes a logic connector (not shown) that interconnects a voltage regulator (not shown) of alternator 1 with ECU 23 via line 25A. It should be noted that, depending on the logical communication infrastructure of the vehicle in which the system is installed, lines 24 and / or 25A, 25B may be independent lines or may be part of a CAN network or an Ethernet network or another network already present in the vehicle.

[0021] FIG. 3 is a chart illustrating a method flow according to the present invention, in which the coupling and / or disengagement of the alternator 1 is a function of the charge level of the battery 20 in combination with the vehicle's operating conditions.

[0022] More specifically, the method of the present invention analyzes the battery charge level status and combines it with the vehicle's operation to indicate the favorable moment for engaging or disengaging the alternator. The main objective of the method is to reduce fuel consumption and therefore vehicle emissions. However, based on the described appropriate strategy, it is also possible to improve the vehicle's driving feel by selecting the best moment for engaging and disengaging the vehicle's alternator. In this way, it is possible to control the engagement of the alternator to avoid the "jolt" inherent in a sudden increase in load on the vehicle's internal combustion engine (ICE) crankshaft. Specifically, the jolt can be defined as a sudden decrease in the vehicle's moving speed caused by a sudden increase in crankshaft load.

[0023] Therefore, first it is necessary to set some operating levels of the battery (20): BC1: corresponds to a fully charged state of the battery - for example, such a fully charged level can be defined as a battery charge of more than 99% relative to the total battery charge level, - BC2: Practical battery charge level, i.e., a charge sufficient to drive the vehicle without risk of impairing the functionality of the electrical system, even for vehicles with several active electrical accessories, if the alternator is not available - for example, this practical charge level can be defined from a battery charge level of 99% to 75% relative to the total battery charge level, BC3: corresponds to a low battery charge level, i.e. a battery charge level that is insufficient to maintain normal vehicle operation within the estimated time - for example, this low battery charge level can be defined as a battery charge level below 75% of the total battery charge level.

[0024] It is appropriate to emphasize that the battery charge level percentages defining charge levels BC1, BC2, and BC3 are merely exemplary and not limiting. As one skilled in the art can appreciate, the battery charge level percentage values ​​may vary depending, among other things, on the total battery charge level and the amount and type of equipment that must be supplied by the vehicle's power system.

[0025] Therefore, the system first tests the battery charge level status to define the behavior of Alternator 1 (E / MS) while driving the vehicle.

[0026] Therefore, when sensor 22 detects that the battery charge level status is at the BC1 level, indicating that battery 20 is fully charged, there is no need to operate alternator 1. In this situation, pulley 4 remains mechanically disengaged from alternator 1, thereby reducing the load on crankshaft 7.

[0027] In the exact opposite situation, where battery 20 is nearly depleted (level BC3), the system understands that restoring the battery charge level is essential, and alternator 1 remains mechanically and electrically coupled, regardless of vehicle usage. This behavior is selected to prevent the battery from compromising its ability to power the vehicle's electrical system. This state is maintained until the battery charge level reaches at least the BC2 charge level. Specifically, the chart in FIG. 3B shows that when the battery charge level (red curve) falls below the "utility range" (BC2), the alternator remains mechanically and electrically coupled (level 1, blue line) until the battery charge level returns to that range.

[0028] Finally, when the load sensor 22 indicates a load condition within the BC2 level, this allows the system to appropriately manage the performance of the alternator 1 to match battery recharging with fuel economy and reduced pollutant emissions.

[0029] To this end, it is possible to define operating states of the invention as shown in FIG. 3, which shows an example of parameters controlled by the system depending in particular on the route taken by the vehicle.

[0030] At time t=0, the vehicle is switched off and the alternator 1 is electrically and mechanically disengaged from the crankshaft 7. In this way, the engine is started (the RPM increases according to the grey line on the chart), this starting being facilitated by the fact that a starter motor (not shown) does not need to run the alternator.

[0031] After starting the engine and before shifting into first gear, the alternator remains mechanically disengaged from the crankshaft. The driver starts to drive the vehicle with the alternator still disengaged—see in particular the black line in the chart showing the vehicle's travel speed. As the speed increases, gears are shifted continuously until the vehicle reaches a limit speed VLim, shown in FIG. 3 as, for example, 40 km / h. From that moment on, the system waits for the next gear change, which constitutes an opportunity to mechanically engage alternator 1. During the period in which the driver operates the clutch pedal (vehicle disengagement) and executes a change from the current gear to the successive gear (this period lasts for several seconds), the system detects this state and has the opportunity to mechanically engage alternator 1; the blue line shows the alternator's mechanical engagement state, with level 1 being engaged and level 0 being disengaged.

[0032] It should be noted that the limit speed VLim is preferably a value that varies depending on the battery's "State of Health" (SoH) and / or the battery's state of charge (SoC). Thus, a higher battery charge level value allows for deferred coupling, which is reflected in coupling occurring at a higher speed VLim, while a battery that has already been used for some time (with reduced charge storage capacity) requires more constant coupling, which is reflected in a decrease in the limit speed VLim.

[0033] At this particular moment, which defines in combination with other essential features of the present invention, the driver of the vehicle does not perceive the mechanical coupling, since it occurs with the engine decoupled from the powertrain: the vehicle maintains its regular movement by inertia, and any jolt of the alternator coupling, directed exclusively towards the engine, is not detected by the vehicle or the driver.

[0034] Once this mechanical coupling of the alternator has been performed, the system finally waits for a second opportunity to perform the electrical connection of the alternator. According to the invention, this opportunity is aimed at the moment when the vehicle is driven in cutoff (the internal combustion engine running maintained by the powertrain and without the accelerator pedal), i.e., when the vehicle is moving along a descending path (acceleration defined only by the force component of gravity), the engine is engaged (one of the gears is engaged, the clutch and the accelerator pedal are not activated), and the engine is rotating at a certain speed (rpm) above a certain limit. For example, in the chart of Figure 3, said limit is established as 1200 rpm.

[0035] Thus, when a cut-off condition is detected, the system has the opportunity to perform the electrical connection of alternator 1, i.e., the rotation of the alternator is performed by the movement of the vehicle in gear (wheels, gearbox, engine, alternator, in that order), and therefore the mechanical energy converted into electricity by the alternator comes exclusively from the "inertial" movement of the vehicle.

[0036] As will be apparent to those skilled in the art, such a state allows charging of the battery 20 at "zero cost" in terms of fuel and with zero pollutant emissions, since fuel injection is deactivated in the cutoff state. In the chart of Figure 3, the red lines indicate periods when the alternator is charging the battery (Level 1) and periods when the battery 20 is not charging (Level 0).

[0037] On the other hand, this form of battery charging is maintained as long as the cut-off condition persists. The speed limit (rpm) that defines the cut-off condition depends primarily on the alternator 1, i.e., its minimum rotational speed that results in significant production of electrical energy, and on the characteristics of the ICE that it can maintain operation within a certain rotational speed without fuel injection. In other words, the engine needs to be at a certain speed in order for other vehicle systems to be fully functional (water pump, oil pump, air conditioning system, etc.), and the speed must be maintained in this case by the vehicle moving.

[0038] In this way, when the engine speed falls below this functional limit (RLim), the system provides for mechanical and electrical disengagement of the alternator. In the chart of Figure 3, it is possible to identify the moment when the vehicle speed drops from approximately 50 km / h to a complete stop of the vehicle (where t is approximately 120 seconds). At a certain point on this curve in the chart (approximately 20 km / h), the engine speed falls below the minimum speed (rpm) limit (RLim), thereby prompting the complete disengagement of alternator 1. When the vehicle starts moving again, the alternator will be recoupled first mechanically and then electrically, provided the above conditions are met.

[0039] In the case of a vehicle with an automated transmission, the performance of the proposed system is exactly the same, since each gear change occurs after the driver indicates the need to make a gear change via actuation of the gear lever. Instead, vehicles with automated transmission systems can follow the coupling procedure as described below for vehicles with automatic transmissions, since in these automated systems, clutch actuation is not done by the driver, but by an actuator commanded by the TCU.

[0040] In the case of so-called automatic transmission engines, the engaged and disengaged states follow exactly the same parameters as those mentioned above, the essential difference being that in this case the TCU is the entity that manages each gear change, and therefore there must be communication (not shown) between the proposed system (i.e. the processor in charge of managing the system) and the TCU via a CAN network or similar, so that the system of the invention informs the TCU of the need to perform an engagement and the TCU informs the system that the vehicle has been disengaged.

[0041] 4 shows various possibilities for the operation of the system of the present invention, from mechanical and electrical coupling at successive moments, provided that both mechanical and electrical coupling conditions (as described above) are met, and, if necessary, based on delaying the shift time by the TCU, since automatic gear changes require too short a time, which, as is known, can prevent or damage the alternator's mechanical and / or electrical coupling.

[0042] Alternatively, and even more advantageously for both vehicles with automatic transmissions and automatic transmissions, the mechanical and electrical couplings can be performed consecutively within the cut-off condition, for example with a time interval of a few tenths of a second between each coupling (while checking the alternator coupling condition). In this situation, since the TCU itself controls the clutching of the transmission (opening moment and duration), it is possible to condense the mechanical and electrical couplings within the cut-off condition in time to reduce the rotational load on the alternator crankshaft (7) as much as possible.

[0043] As a result of both the system and the method proposed by the present invention, tests already carried out by the inventors have shown that it is possible to obtain a reduction in fuel consumption and therefore in polluting gas emissions of the order of 3 to 4% compared to vehicles in which the alternator is of the conventional type (always mechanically and electrically coupled to the vehicle).

[0044] This advantage results, inter alia, from the following particularities of the proposed system:

[0045] First, it is possible to start the vehicle engine with the alternator disengaged and also to start the vehicle running with the alternator disengaged, such a scenario reducing the mechanical load on the engine and reducing the need for injected fuel.

[0046] Shifting the battery charging period to the vehicle's cut-off state allows the battery to be charged without consuming fuel, simply by taking advantage of the terrain shape.

[0047] The setting of three battery charge levels (BC1, BC2 and BC3) and their specific operating procedures allow the vehicle to be driven safely without the risk of discharging the battery, which could damage its electrical system. It should be noted that with the system of the present invention, the electrical supply of the vehicle system is primarily provided by the battery and no longer by the alternator as in conventional vehicles.

[0048] Another advantage of the proposed system is the reduction of engine load under conditions of stronger power demand, for example: thus, when the driver indicates an overtaking maneuver (fully depressed accelerator pedal and consequent downshift), the alternator can be fully disengaged.

[0049] During idling (e.g., when the vehicle is stationary or disconnected) and while the battery is being charged in the utility regime, the alternator remains disengaged, which therefore means a significant reduction (30-40%) in fuel consumption in this state.

Claims

1. A method for managing an automotive alternator, comprising: determining the battery charge level between BC1 (corresponding to a fully charged state of the battery), BC2 (corresponding to a practical battery charge level) and BC3 (corresponding to a low battery charge level); - at level BC1, the alternator (1) is kept electrically and mechanically disconnected; At level BC3, the alternator (1) remains electrically and mechanically coupled, and At level BC2, the alternator (1) is mechanically coupled when the vehicle's speed of travel is greater than a given value (VLim) and when the engine (ICE) is disengaged for a gear change, and the alternator (1) is electrically connected when the vehicle is driven in cut-off mode.

2. 2. The method of claim 1, further comprising the step of mechanically and electrically disengaging the alternator (1) if the engine rotation speed is below a given limit value (RLim).

3. The method of claim 1, wherein the given value of vehicle speed (VLim) varies depending on the health state of the battery and / or the charge level of the battery (20).

4. 10. A management system for an alternator for a motor vehicle for carrying out the method according to claim 1, comprising a vehicle with an engine (ICE), the rotation of a crankshaft (7) being transmitted to the alternator (1) via a toothed belt (5), the vehicle also comprising a battery (20) for supplying the vehicle's electrical system, and a battery charge sensor (22), the alternator (1) being controlled by an ECU (23), the ECU being able to act on a pulley (4) to facilitate a mechanical coupling of the alternator (1) with the toothed belt (5) and an electrical coupling with the battery (20), the ECU receiving a signal from the battery charge sensor (22) to: determining the battery charge level between BC1 (corresponding to a fully charged state of said battery), BC2 (corresponding to a practical battery charge level) and BC3 (corresponding to a low battery charge level); For the alternator (1), - at level BC1, the alternator (1) is kept electrically and mechanically decoupled; At level BC3, the alternator (1) remains electrically and mechanically coupled, and - at level BC2, a management system which acts to mechanically couple the alternator (1) when the vehicle's speed of movement is greater than a given value (VLim) and when the engine (ICE) is disengaged for a gear change, and to electrically couple the alternator (1) when the vehicle is driven in cut-off mode.

5. 5. The system of claim 4, wherein the ECU (23) mechanically and electrically disengages the alternator (1) when the engine rotation speed is below a given limit value (RLim).

6. The system described in claim 4, wherein the given value (VLim) of vehicle speed varies depending on the health state of the battery (20) and / or the amount of charge of the battery (20).

Images