System for controlling regeneration in a hybrid-powered vehicle

Abstract

Regeneration control system for a hybrid-powered motor vehicle (1) which is powered by an internal combustion engine (2) and / or an electric motor (4), wherein the regeneration control system comprises the following: a control (9) for implementing a control plan for regenerative braking, in which, after it is determined that an operator brake input is greater than a predetermined value, the amount of regeneration by the electric motor (4) is reduced in HEV mode, in which both the combustion engine (2) and the electric motor (4) supply power to drive the hybrid-powered vehicle (1), more than in EV mode, in which only the electric motor (4) supplies power to drive the hybrid-powered vehicle (1). where the control unit (9) executes the control plan for regenerative braking, in which the size of the regeneration by the electric motor (4) is reduced more in HEV mode than in EV mode, after it is determined that a vehicle speed is lower than a predetermined vehicle speed, and whereby the control (9) executes the control plan for regenerative braking if a time derivative of an internal combustion engine speed is greater than a predetermined threshold.

Description

[Technical field]

[0001] The present invention relates to a regeneration control system for a hybrid-powered motor vehicle. [Background of the technology]

[0002] JP 2017 - 136 885 A discloses a control system for a hybrid-powered motor vehicle (also called a "hybrid electric vehicle") that is capable of improving fuel efficiency by determining a target braking force for decelerating drive wheels based on operator braking input, vehicle speed and body weight, and by ensuring that, in a case where the determined target braking force is not greater than the maximum regenerative braking force of the motor generator, a maximum magnitude of regeneration achieved by a motor generator and resulting from a braking operation is achieved solely through regenerative braking by the motor generator. [State of the art][Patent literature]

[0003] Patent literature 1: JP 2017 - 136 885 A [Summary of the invention][Technical problem]

[0004] However, JP 2017 - 136 885 A does not take into account the characteristics of the electric vehicle mode (EV mode), in which only the motor generator provides power to drive a vehicle, nor the characteristics of the hybrid electric vehicle mode (HEV mode), in which both the internal combustion engine and the motor generator provide power to drive a vehicle.

[0005] If the regeneration size is too large in HEV mode, the load on the combustion engine increases, thus preventing an excessive increase in engine speed, which can lead to the combustion engine stalling. Conversely, if the regeneration size is too small, sufficient regeneration cannot be guaranteed.

[0006] DE 697 00 639 T2 discloses a control system for hybrid vehicles with an internal combustion engine and a traction motor as primary drives, which is suitable for controlling the regeneration of electrical energy. Rapid deceleration of the vehicle is detected based on the vehicle's operating conditions. Using the control system, when rapid deceleration is detected, the power output of the traction motor can be controlled to a predetermined positive value.

[0007] WO 2012 / 070 105 A1 discloses an electric vehicle comprising a battery, an electric motor, and a motor control unit. The motor control unit comprises a regeneration control device for initiating a regeneration process to supply the regeneration current generated by the electric motor to the battery when a predetermined accelerator pedal actuation is detected, as well as means for setting a maximum regenerative current to a first fixed value when the predetermined accelerator pedal actuation is detected, and for setting the maximum regenerative current to a second fixed value when the actuation of a brake actuator is detected.

[0008] US Patent 2005 / 0184529A1 discloses a drive system for a hybrid electric vehicle comprising a motor, a first motor / generator, a second motor / generator, and a battery electrically connected to both the first and second motors / generators. If a failure of the first or second motor / generator is detected, a control system limits the rotation of the second motor / generator via a clutch, thus ensuring the vehicle's operation and battery charging through motor power.

[0009] DE 10 2013 224 379 A1 discloses a method for controlling a hybrid vehicle comprising an internal combustion engine, an electric motor, a transmission with a starting element, and a coupling element for coupling the internal combustion engine to the electric motor. In recuperation mode, where the electric motor is operated as a generator, if a determined rotational speed of the internal combustion engine is less than or equal to a minimum rotational speed of the internal combustion engine, the coupling element is controlled such that the internal combustion engine is at least partially decoupled from the electric motor.

[0010] DE 100 49 550 A1 discloses a system for regeneration control of a hybrid vehicle which is driven by a (combustion engine) engine and an electric motor, and in particular a system which prevents the engine from stalling due to a sudden decrease in engine speed during deceleration regeneration.

[0011] The object of the present invention is to provide a regeneration control system for a hybrid-powered motor vehicle that is capable of increasing the total amount of regeneration without stalling the combustion engine in HEV mode. [Solution to the task]

[0012] A regeneration control system is provided for a hybrid-powered vehicle driven by an internal combustion engine and / or an electric motor. The regeneration control system comprises: a controller for executing a regeneration control plan, in which, after it has been determined that an operator brake input is greater than a predetermined value, the amount of regeneration by the electric motor is reduced more in HEV mode, where both the internal combustion engine and the electric motor supply power to drive the hybrid-powered vehicle, than in EV mode, where only the electric motor supplies power to drive the hybrid-powered vehicle; and the controller executes the regenerative braking control plan, in which the amount of regeneration by the electric motor is reduced more in HEV mode than in EV mode, after it has been determined that...that a vehicle speed is lower than a predetermined vehicle speed, and wherein the control system executes the regenerative braking control plan if a time derivative of the internal combustion engine speed is greater than a predetermined threshold. [Advantageous effect of the invention]

[0013] As previously described, the regeneration control system is capable of increasing the total amount of regeneration without stalling the combustion engine in HEV mode. [Brief description of the drawings] Fig. Figure 1 is a block diagram representing a regeneration control system for a hybrid-powered vehicle. Fig. Figure 2 is a flowchart of a regeneration control plan. [Detailed description]

[0014] A regeneration control system is provided for a hybrid-powered vehicle driven by an internal combustion engine and / or an electric motor. The regeneration control system includes: a controller for executing a regeneration control plan, whereby, after it has been determined that an operator brake input is greater than a predetermined value, the amount of regeneration by the electric motor is reduced in HEV mode, where both the internal combustion engine and the electric motor supply power to drive the hybrid-powered vehicle, more so than in EV mode, where only the electric motor supplies power to drive the hybrid-powered vehicle.The control system is configured to execute the regenerative braking control plan, in which the size of the regeneration by the electric motor is reduced more in HEV mode than in EV mode, after it is determined that a vehicle speed is lower than a predetermined vehicle speed, and to execute the regenerative braking control plan if a time derivative of the combustion engine speed is greater than a predetermined threshold.

[0015] For this reason, the regeneration control system is able to increase the total amount of regeneration without stalling the combustion engine in HEV mode. [Version(s)]

[0016] With reference to the attached drawings, the present embodiment of a regeneration control system according to the invention for a hybrid-powered motor vehicle is described below.

[0017] Referring to the Fig. 1 comprises a hybrid-powered motor vehicle 1 in which the regeneration control system is installed: an internal combustion engine 2; a transmission 3; an electric motor 4; an inverter 5; a battery 6; an engine control module (ECM) 7 for the internal combustion engine 2; a transmission control module (TCM) 8 for the transmission 3; and a control unit 9 for controlling the entire motor vehicle 1.

[0018] The internal combustion engine 2 is designed with a plurality of cylinders. In this example, the piston in each of the cylinders performs four separate strokes during the rotation of the crankshaft, i.e., an intake stroke, a compression stroke, a combustion stroke, and an exhaust stroke.

[0019] The transmission 3 receives the rotation of the internal combustion engine 2, changes gears, and drives the drive wheels 10 via drive axles 11. The transmission 3 includes a shifting mechanism (not shown) in the form of a continuously meshing spur gear system.

[0020] A single-disc dry clutch 31 is provided between the internal combustion engine 2 and the transmission 3. The clutch 31 is located in the power transmission path between the internal combustion engine 2 and the transmission 3 and engages or disengages the power transmission path.

[0021] The transmission 3 is an automated manual transmission (AMT) in which the shifting of gears in the shifting mechanism and the disengagement of the clutch 31 are carried out by actuators.

[0022] A differential gear 32 is arranged between the gearbox 3 and the drive wheels 10. Drive axles 11 connect the differential gear 32 to the drive wheels 10.

[0023] The electric motor 4 is connected to the differential gear 32 via a reduction gearbox 41 comprising a chain drive. The electric motor 4 serves as a power source. The electric motor 4, which also serves as a generator, produces electric current while the motor vehicle 1 is in motion.

[0024] The inverter 5 is controlled by the controller 9 to convert a three-phase alternating current generated by the electric motor 4 into a direct current used, for example, to charge the battery 6.

[0025] In this example, battery 6 is a lithium-ion battery. Battery 6 supplies inverter 5 with electrical power.

[0026] A battery sensor 6a is provided for battery 6. The battery sensor 6a detects an electrical current, voltage, and temperature during the discharge or charging of battery 6. The battery sensor 6a is connected to the controller 9. The controller 9 can detect the state of charge (SOC) of battery 6 in response to an output provided by the battery sensor 6a.

[0027] As previously described, the motor vehicle 1 comprises a parallel hybrid powertrain in which power from the internal combustion engine 2 and power from the electric motor 4 can be used to drive the motor vehicle 1, so that the internal combustion engine 2 and / or the electric motor 4 can drive the motor vehicle 1.

[0028] The connection of the electric motor 4 with the differential gear 32 is not always necessary, because a connection of the electric motor 4 with any point of the power transmission path between the internal combustion engine 2 and the drive wheels 10 also works.

[0029] The ECM 7, the TCM 8 and the controller 9 are each a computing unit that includes a central processing unit (CPU), a working memory (RAM), a read-only memory (ROM), a flash memory for data backup, input ports and output ports.

[0030] The ROM of each of the computer units stores, along with various constants and different characteristic maps, computer-readable programs, which enable the computer units to operate as ECM 7, TCM 8 and control 9.

[0031] When the CPU executes the programs stored in the ROM using the RAM as a workspace, these computing units thus operate as ECM 7, TCM 8 and control 9.

[0032] In the hybrid-powered motor vehicle 1, a CAN communication line 12 is used to form a local area network (LAN) that meets the standard of a CAN network (Controller Area Network).

[0033] The ECM 7, the TCM 8, and the control unit 9 are interconnected via CAN communication line 12. The ECM 7, the TCM 8, and the control unit 9 send and / or receive signals, such as control signals, to each other via CAN communication line 12.

[0034] Various sensors, including an internal combustion engine speed (or RPM) sensor 93 (not shown), are connected to the input ports of the ECM 7. The internal combustion engine speed sensor 93 detects the internal combustion engine speed of the internal combustion engine 2, i.e., the internal combustion engine RPM.

[0035] Various devices or units to be controlled, including the fuel injectors (not shown), are connected to the output ports of the ECM 7. The fuel injectors are arranged for injecting fuel into the internal combustion engine 2.

[0036] The output ports of the TCM 8 are connected to various devices or units to be controlled, including the actuators for the transmission 3. The TCM 8 performs gear-changing operations in the shifting mechanism of the transmission 3 and engages and disengages the clutch 31 by controlling the actuators for the transmission 3.

[0037] The input ports of the controller 9 are connected to various sensors, which, in addition to the previously mentioned battery sensor 6a, include a brake stroke sensor 91, a vehicle speed sensor 92 and an accelerator pedal position sensor (not shown).

[0038] The brake stroke sensor 91 detects an operator brake input BR input or a brake pedal actuation level to which an operator presses on a brake pedal (not shown) and outputs a signal for the control unit 9, which represents the operator's brake input BR input or represents the degree of brake pedal actuation.

[0039] The vehicle speed sensor 92 detects a vehicle speed VS of the motor vehicle 1 and outputs a signal representing the vehicle speed to the control unit 9.

[0040] The accelerator pedal position sensor detects the position of an accelerator pedal (not shown) and outputs a signal representing the accelerator pedal position to the control unit 9.

[0041] The output ports of the controller 9 are connected to various devices or units to be controlled, including the inverter 5 mentioned above.

[0042] In the present embodiment, the control unit 9 determines a torque requested by an operator based on the accelerator pedal position and the vehicle speed. Depending on the requested torque, the control unit 9 determines a target drive axle torque, i.e., a torque exerted on the drive axles 11, so that the requested torque is applied to the drive wheels 10. The control unit 9 regulates the internal combustion engine 2 and the electric motor 4 such that the specified target drive axle torque is exerted on the drive axles 11.

[0043] The control unit 9 transmits a torque command to the ECM 7. The ECM 7 causes the internal combustion engine 2, as output, to generate a torque that is as high as the torque value specified in the torque command.

[0044] The control unit 9 determines a torque to be generated by the combustion engine 2 and a torque to be generated by the electric motor 4 based on the target drive axle torque and the state of charge (SOC) of the battery 6.

[0045] The control unit 9 switches between HEV and EV modes based on the state of charge (SOC) of the battery 6 and the requested torque. In HEV mode, both the combustion engine 2 and the electric motor 4 supply power to the drive axles 11 to propel the vehicle 1. In EV mode, only the electric motor 4 supplies power to the drive axles 11 to propel the vehicle 1.

[0046] Control unit 9 disengages clutch 31 to prevent the internal combustion engine from stalling if the engine speed drops below a predetermined speed during deceleration of the vehicle 1. The predetermined speed is the internal combustion engine's idle speed (RPM). idle .

[0047] The control unit 9 causes the electric motor 4 to generate a generator torque in order to produce electrical power to charge the battery 6 during the deceleration of the motor vehicle 1.

[0048] The controller 9 executes a control plan for regenerative braking in which the size of the regeneration by the electric motor 4 is reduced more in HEV mode than in EV mode, after it has been determined that the operator brake input BR input during the deceleration of motor vehicle 1, the value BR is greater than a predetermined value. predThe regeneration quantity is the magnitude of the generator torque to be produced by the electric motor. The regeneration quantity can be controlled by changing the field current in the electric motor 4.

[0049] The control unit 9 executes the control plan for regenerative braking, in which the size of the regeneration by the electric motor is reduced more in HEV mode than in EV mode, after it has been determined that the vehicle speed VS during the deceleration of the vehicle 1 is lower than a predetermined vehicle speed VS pred is.

[0050] Control unit 9 executes the control plan for regenerative braking, in which the size of the regeneration by the electric motor is reduced more in HEV mode than in EV mode, after it has been determined that the combustion engine speed RPM during the deceleration of vehicle 1 is lower than a combustion engine idle speed RPM idle The control unit 9 can execute the control plan for regenerative braking, in which the size of the regeneration by the electric motor is reduced more in HEV mode than in EV mode, if the time derivative of the combustion engine speed is greater than a predetermined threshold.

[0051] Control unit 9 executes the control plan for regenerative braking with the setting that, after it is determined that the vehicle speed VS during the deceleration of motor vehicle 1 is lower than the predetermined vehicle speed VS predThe lower the vehicle speed, the smaller the regeneration size.

[0052] Implementing such a control plan for regenerative braking can prevent the combustion engine from stalling in HEV mode. Furthermore, the total amount of regeneration in EV mode can be increased by extending the operating range in which regeneration takes place.

[0053] The control unit 9 can use a map retrievable by a computer, which specifies varying regeneration sizes with different vehicle speeds, in order to determine the appropriate regeneration size during the deceleration of the vehicle 1.

[0054] The control unit 9 can use an initial map, which specifies varying regeneration parameters at different vehicle speeds, to determine the appropriate regeneration parameters, for example, after it has been determined that during the deceleration of the vehicle 1 in EV mode, the operator brake input BR input greater than the predetermined value BR pred and the vehicle speed VS is lower than the predetermined vehicle speed VS pred are.

[0055] The control unit 9 can use a second map, which specifies varying regeneration sizes at different vehicle speeds, to determine the appropriate regeneration size, for example, after it has been determined that during the deceleration of vehicle 1 in HEV mode, the operator brake input BR input greater than the predetermined value BR pred, the vehicle speed VS is lower than the predetermined vehicle speed VS pred , and the internal combustion engine speed (RPM) is lower than the internal combustion engine idle speed (RPM). idle are.

[0056] The control unit 9 can use the aforementioned first map, which specifies varying regeneration sizes at different vehicle speeds, to determine the appropriate regeneration size, for example, after it has been determined that during deceleration of vehicle 1 in HEV mode, the operator applies brake input BR. input greater than the predetermined value BR pred , the vehicle speed VS is lower than the predetermined vehicle speed VS pred , and the internal combustion engine speed (RPM) is not lower than the internal combustion engine idle speed (RPM). idle are.

[0057] Control unit 9 uses the second map instead of the first map to stop regeneration at high vehicle speeds by setting the second map to specify a lower regeneration value than any other regeneration value specified in the first map, at the same vehicle speed.

[0058] The occurrence of the combustion engine stalling in HEV mode can be prevented by using the first and second maps.

[0059] Furthermore, the total amount of regeneration in EV mode can be increased by extending the operating range in which regeneration is performed.

[0060] The control unit 9 can use a third characteristic map during the deceleration of the motor vehicle 1, after it has been determined, for example, that the operator brake input BR input not greater than the predetermined value BR predAt the same vehicle speed, the third map indicates a regeneration value that is lower than another regeneration value specified in the second map.

[0061] If the time derivative of the combustion engine speed is greater than the predetermined threshold, the control unit 9 can execute the regenerative braking control plan.

[0062] When clutch 31 is disengaged to prevent the internal combustion engine from stalling, special attention must be paid to how long it takes to disengage the internal combustion engine 2. The problem is that if the internal combustion engine speed (RPM) drops rapidly, the internal combustion engine 2 may stall before clutch 31 is fully disengaged.

[0063] To solve the problem mentioned above, the regeneration size is reduced to prevent the combustion engine from stalling after it is determined that the reduction rate of the combustion engine speed RPM is lower than the predetermined threshold.

[0064] Referring to the Fig. Section 2 describes the control plan for regenerative braking implemented by the regeneration control system according to the invention for a hybrid-powered motor vehicle. This regeneration control plan is executed by the controller 9, begins when the deceleration of the motor vehicle 1 starts, and ends when the deceleration subsequently ends. The following steps are repeated at regular intervals.

[0065] In step S1, it is determined whether the operator brake input BR input greater than the predetermined value BR pred is. If the operator brake input BRinput not greater than the predetermined value BR pred If the condition is met, the control system proceeds to step S7 and then terminates the process. In step S7, the third characteristic map is retrieved with the vehicle speed VS to determine the regeneration size.

[0066] If in step S1 the operator brake input BR input greater than the predetermined value BR pred If so, the control system proceeds to step S2. In step S2, it is determined whether the vehicle speed VS of vehicle 1 is lower than the predetermined vehicle speed VS. pred is or is not. If the vehicle speed VS is lower than the predetermined vehicle speed VS pred If the control system is not functioning correctly, it proceeds to step S3. In step S3, it is determined whether the vehicle 1 is in EV mode or not.

[0067] If vehicle 1 is not in EV mode, but rather in HEV mode, the control system proceeds to step S4. In step S4, it is determined whether the combustion engine speed (RPM) is lower than the combustion engine idle speed (RPM). idle This is the case if the internal combustion engine speed (RPM) is lower than the internal combustion engine idle speed (RPM). idle If the condition is met, the control system proceeds to step S6 and then exits the process. In step S6, the second characteristic map is retrieved with the vehicle speed VS to determine the regeneration size.

[0068] If in step S2 the vehicle speed VS is not lower than the predetermined vehicle speed VS pred is or the vehicle 1 is in EV mode in step S3 or the combustion engine speed RPM in step S4 is not lower than the combustion engine idle speed RPM idleIf the condition is met, the control system proceeds to step S5 and then exits the process. In step S5, the first characteristic map is retrieved with the vehicle speed VS to determine the regeneration parameter.

[0069] As described, the occurrence of the combustion engine stalling in HEV mode can be avoided if the amount of regeneration by the electric motor is reduced more in HEV mode than in EV mode. Furthermore, the total amount of regeneration can be increased in EV mode by extending the operating range in which regeneration takes place.

[0070] Although the present disclosure focuses on an example of the present embodiment in which the controller 9 performs various determinations and calculations based on information from different sensors, the present embodiment is not limited to this example. For example, the motor vehicle 1 can include a communication unit capable of sending detection results from various sensors to an external unit, such as a server, which performs various determinations, and receiving the results of the determinations and calculations performed by the external unit. Based on the results of the determinations and calculations received by the communication unit, the present embodiment can perform various control actions. [Description of reference symbols] 1 hybrid powered motor vehicle or hybrid electric vehicle; 2 Internal combustion engine; 4 electric motors; 5 inverters; 6 batteries; 6a Battery sensor 7 Engine Control Module (ECM) 8 Transmission Control Module (TCM) 9 Control; 10 drive wheels 11 drive axles 12 Communications line 31 Clutch 32 Differential gears 41 Reduction gearbox 91 Brake stroke sensor; 92 Vehicle speed sensor; 93 Internal combustion engine speed sensor.

Claims

[1] Regeneration control system for a hybrid-powered motor vehicle (1) driven by an internal combustion engine (2) and / or an electric motor (4), the regeneration control system comprising: a controller (9) for executing a regenerative braking control plan in which, after determining that an operator braking input is greater than a predetermined value, an amount of regeneration by the electric motor (4) is reduced more in the HEV mode, in which both the internal combustion engine (2) and the electric motor (4) supply power to drive the hybrid-powered motor vehicle (1), than in the EV mode, in which only the electric motor (4) supplies power to drive the hybrid-powered motor vehicle (1), where the controller (9) executes the regenerative braking control plan in which the amount of regeneration by the electric motor (4) is reduced more in the HEV mode than in the EV mode, after determining that a vehicle speed is lower than a predetermined vehicle speed, and where the controller (9) executes the regenerative braking control plan if a time derivative of an internal combustion engine speed is greater than a predetermined threshold value.

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