JP2019001302A - Device for controlling drive of vehicle - Google Patents

Abstract

To provide a device for controlling drive of a vehicle that can suppress generation of vibration in a vehicle body at engine starting during EV mode.SOLUTION: A device for controlling drive of a hybrid vehicle includes ISG for starting an engine and ECM capable of executing F/C. ECM prohibits F/C based on a condition that an F/C prohibition condition is met when ISG re-starts the engine during EV mode of stopping the operation of the engine and capable of travelling with drive power of a motor generator.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a vehicle drive control device.

  In Patent Document 1, for the purpose of suppressing the vibration of the vehicle body due to the fuel cut, the power is transmitted from the engine to the drive wheels at a predetermined timing before the fuel cut is started when the fuel cut of the engine is executed. It is disclosed that vehicle body vibration due to torque fluctuation is generated by changing the engagement state of engagement elements provided on a path.

  Further, in Patent Document 1, the predetermined timing for generating the vehicle body vibration due to the change in the engagement state includes the phase of the vehicle body vibration due to the change in the engagement state and the phase of the vehicle body vibration due to the change in the engine torque due to the fuel cut. It is described that the timing is the opposite phase.

Japanese Patent Laying-Open No. 2015-209005

  By the way, in a hybrid vehicle that travels by the driving force of at least one of the engine and the motor, the engine may be started during the EV mode that can travel by the driving force of the motor. In this case, the fuel of the engine is cut. Sometimes. If fuel cut is performed during the EV mode, the engine torque fluctuates, and there is a risk that vehicle body vibration will occur due to the fluctuation of the engine torque.

  The thing of the above-mentioned patent document 1 is not considered about suppressing the vehicle body vibration at the time of engine starting in EV mode as mentioned above.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle drive control device that can suppress the occurrence of vehicle body vibration when the engine is started in the EV mode.

  In order to achieve the above object, the present invention provides a drive control device for a vehicle that has a starter for starting an engine and travels by the driving force of at least one of the engine and the motor, and performs fuel injection to the engine. A control unit capable of executing a fuel cut to stop, wherein the control unit stops the operation of the engine and starts the engine by the start unit during an EV mode in which the vehicle can be driven by the driving force of the motor The fuel cut is prohibited on condition that a predetermined fuel cut prohibition condition is satisfied.

  ADVANTAGE OF THE INVENTION According to this invention, the drive control apparatus of the vehicle which can suppress that a vehicle body vibration generate | occur | produces at the time of engine start in EV mode can be provided.

FIG. 1 is a schematic configuration diagram of a hybrid vehicle including a drive control apparatus according to an embodiment of the present invention. FIG. 2 is a flowchart showing a flow of F / C determination control processing executed by the drive control apparatus according to the embodiment of the present invention. FIG. 3 is a diagram illustrating a relationship between a torque request value for TCM and a torque threshold value for F / C permission when F / C is prohibited in F / C determination control according to an embodiment of the present invention. FIG. 4 is a diagram illustrating a relationship between a torque request value for TCM and a torque threshold value for F / C permission in the case of F / C permission in F / C determination control according to an embodiment of the present invention. FIG. 5 is a graph for explaining the operation of the drive control apparatus according to the embodiment of the present invention.

  A drive control apparatus for a vehicle according to an embodiment of the present invention is a drive control apparatus for a vehicle that has a starting unit that starts an engine and travels by the driving force of at least one of an engine and a motor. A control unit capable of executing fuel cut for stopping fuel injection is provided, and the control unit is predetermined when the engine is started by the starting unit during the EV mode in which the operation of the engine is stopped and the motor can be driven by the driving force of the motor. The fuel cut is prohibited on condition that the fuel cut prohibition condition is satisfied. Thereby, it is possible to suppress the occurrence of vehicle body vibration when the engine is started in the EV mode.

  Hereinafter, a hybrid vehicle equipped with a drive control apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, a hybrid vehicle 1 as a vehicle includes an engine 2, a transmission 3, a motor generator 4 as a motor, drive wheels 5, an ECM (Engine Control Module) 11 that controls the engine 2, And a TCM (Transmission Control Module) 12 for controlling the transmission 3.

  The engine 2 is formed with a plurality of cylinders. In this embodiment, the engine 2 is configured to perform a series of four strokes including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke for each cylinder.

  The engine 2 is connected with an ISG (Integrated Starter Generator) 20 and a starter 21. The ISG 20 and the starter 21 of this embodiment each constitute a starter.

  The ISG 20 is connected to the crankshaft 18 of the engine 2 via a belt 22. The ISG 20 has a function of an electric motor that rotates when the engine 2 is rotated by being supplied with electric power, and a function of a generator that converts the rotational force input from the crankshaft 18 into electric power.

  In this embodiment, the ISG 20 restarts the engine 2 from the stop state by the idling stop function by functioning as an electric motor under the control of the ECM 11. The ISG 20 can also assist the traveling of the hybrid vehicle 1 by functioning as an electric motor.

  The starter 21 includes a motor and a pinion gear (not shown). The starter 21 rotates the crankshaft 18 by rotating the motor, and gives the engine 2 a starting torque. As described above, the engine 2 is started by the starter 21 and restarted by the ISG 20 from the stop state by the idling stop function.

  The transmission 3 shifts the rotation output from the engine 2 and drives the drive wheels 5 via the drive shaft 23. The transmission 3 includes a constantly meshing transmission mechanism 25 including a parallel shaft gear mechanism, a clutch 26 constituted by a normally closed type dry clutch, a differential mechanism 27, and an actuator (not shown).

  The transmission 3 is configured as a so-called AMT (Automated Manual Transmission). The actuator controlled by the TCM 12 switches the gear position in the transmission mechanism 25 and connects and disengages the clutch 26. The differential mechanism 27 is configured to transmit the power output by the speed change mechanism 25 to the drive shaft 23.

  The motor generator 4 is connected to the differential mechanism 27 via a power transmission mechanism 28 such as a chain. The motor generator 4 functions as an electric motor.

  Thus, the hybrid vehicle 1 forms a parallel hybrid system that can use the power of both the engine 2 and the motor generator 4 for driving the vehicle, and the driving force of at least one of the engine 2 and the motor generator 4 is configured. Travel by.

  The motor generator 4 also functions as a generator, and generates power when the hybrid vehicle 1 travels. The motor generator 4 may be connected to any part of the power transmission path from the engine 2 to the drive wheel 5 so as to be able to transmit power, and is not necessarily connected to the differential mechanism 27.

  Each of the ECM 11 and the TCM 12 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory for storing backup data, an input port, and an output port. The computer unit is provided.

  ROMs of these computer units store various constants, various maps, and the like, and programs for causing the computer units to function as the ECM 11 and the TCM 12, respectively.

  That is, when the CPU executes a program stored in the ROM using the RAM as a work area, these computer units function as the ECM 11 and the TCM 12 in this embodiment, respectively.

  In the present embodiment, the ECM 11 performs idling stop control. In this idling stop control, the ECM 11 stops the engine 2 when a predetermined stop condition is satisfied, and drives the ISG 20 to restart the engine 2 when the predetermined restart condition is satisfied. For this reason, unnecessary idling of the engine 2 is not performed, and the fuel efficiency of the hybrid vehicle 1 can be improved.

  Further, the ECM 11 performs a fuel cut (hereinafter referred to as “F / C”) that stops fuel injection to the engine 2 on condition that a predetermined fuel cut condition is satisfied. The predetermined fuel cut condition includes, for example, that the predetermined stop condition in the idling stop control described above is satisfied, or that the accelerator opening is “0” and the hybrid vehicle 1 is decelerated.

  In the present embodiment, the ECM 11 can execute the above-described F / C even when F / C permission is given by F / C determination control described later executed during the EV mode. The F / C in the EV mode is executed, for example, when so-called torque reduction is performed to reduce the engine torque in response to a torque reduction request from the TCM 12 when the engine 2 is started during the EV mode.

  In the present embodiment, the EV mode means that the hybrid vehicle 1 is in an EV travelable state in addition to the EV travel in which the operation of the engine 2 is stopped and the hybrid vehicle 1 is actually traveled by the driving force of the motor generator 4. Including a state where the vehicle is stopped or stopped.

  The ECM 11 is connected to an accelerator opening detector 31, a vehicle speed detector 32, and an engine rotation speed detector 33.

  The accelerator opening detection unit 31 detects an accelerator opening Acc that represents an operation amount of an accelerator pedal (not shown), and outputs a signal corresponding to the accelerator opening Acc to the ECM 11. The vehicle speed detection unit 32 detects a vehicle speed V representing the traveling speed of the hybrid vehicle 1 and outputs a signal corresponding to the vehicle speed V to the ECM 11. The engine rotation speed detection unit 33 detects an engine rotation speed Ne representing the rotation speed of the engine 2 and outputs a signal corresponding to the engine rotation speed Ne to the ECM 11.

  Next, F / C determination control executed by the drive control apparatus according to the present embodiment will be described with reference to FIG. The F / C determination control shown in FIG. 2 is repeatedly executed by the ECM 11 at predetermined time intervals during the EV mode.

  As shown in FIG. 2, the ECM 11 determines whether or not a start condition for the engine 2 is satisfied (step S1). As a case where the starting condition of the engine 2 is established during the EV mode, for example, when a compressor of an air conditioner (not shown) is driven, any of various batteries for supplying electric power to the electrical components including the motor generator 4 and the ISG 20 If the battery's SOC (State of Charge) decreases until it falls below a predetermined value, the accelerator pedal (not shown) is depressed more than a certain amount, or a predetermined restart condition is satisfied during idling stop control Cases.

  If the ECM 11 determines that the start condition of the engine 2 is not satisfied in step S1, the ECM 11 prohibits the F / C because it is not necessary to perform the F / C because the engine 2 is not started or operated. (Step S7), and the F / C determination control ends.

  If the ECM 11 determines in step S1 that the engine 2 start condition is satisfied, the ECM 11 starts the engine 2 (step S2). Hereinafter, starting of the engine 2 in the EV mode is referred to as “restart”.

  Next, the ECM 11 determines whether or not the torque request value Tr of the TCM is less than the F / C permission torque threshold Tth (step S3).

  The torque request value Tr of the TCM is a rotational speed between the engine rotational speed Ne of the engine 2 restarted during the EV mode and the rotational speed Ni of the input shaft 25A of the transmission mechanism 25 so that the clutch 26 can be smoothly connected. This is the value of the engine torque required from the TCM 12 to the engine 2 in order to reduce the difference.

The F / C permission torque threshold Tth is calculated by the following equation (1).
Tth = Tfc + (Tbl−Tfc) × P (1)
In the above equation (1), Tth represents a torque threshold for F / C permission, Tfc represents engine torque at F / C, Tbl represents a combustion lower limit torque, and P represents a predetermined ratio.

  The engine torque Tfc at the time of F / C is an estimated value, and is calculated by the ECM 11 by a map or calculation based on the engine rotation speed Ne, the load of the ISG 20, or the like. The combustion lower limit torque Tbl is the minimum engine torque necessary for the engine 2 to maintain combustion. The predetermined ratio P is a ratio such that the torque threshold value Tth is set to the upper limit of a range in which it can be determined that the torque request value Tr is close to the engine torque Tfc at the time of F / C so that the clutch 26 can be smoothly connected. It is obtained in advance based on the specifications of the engine 2 and stored in the ROM of the ECM 11.

  If the ECM 11 determines in step S3 that the torque request value Tr is not less than the torque threshold value Tth, the ECM 11 prohibits F / C (step S7) and ends the F / C determination control.

  FIG. 3 is a diagram illustrating the relationship between various engine torques when the torque request value Tr is equal to or greater than the torque threshold value Tth. As shown in FIG. 3, when the torque request value Tr is equal to or greater than the torque threshold value Tth, when F / C is executed, the engine torque Tfc at the time of F / C greatly falls below the torque request value Tr. For this reason, the engine 2 cannot output the engine torque required by the TCM 12. Therefore, in this embodiment, as described above, when the ECM 11 determines that the torque request value Tr is not less than the torque threshold value Tth in step S3, F / C is prohibited. As a result, in the engine 2, the engine torque is not greatly reduced, and it is possible to output an engine torque close to the engine torque required by the TCM 12.

  On the other hand, FIG. 4 is a diagram showing the relationship between various engine torques when the torque request value Tr is less than the torque threshold value Tth. As shown in FIG. 4, when the torque request value Tr is less than the torque threshold value Tth, the engine torque Tfc close to the torque request value Tr can be output by executing F / C. For this reason, when the torque request value Tr is less than the torque threshold value Tth, even if F / C is permitted, the engine torque requested by the TCM 12 cannot be output.

  If the ECM 11 determines in step S3 that the torque request value Tr is less than the torque threshold value Tth, the ECM 11 determines whether or not the engine rotational speed Ne is greater than the F / C possible rotational speed Nefc (step S4). The F / C possible rotation speed Nefc is a lower limit of the engine rotation speed at which there is no possibility of engine stall at the time of return from F / C, and is experimentally obtained in advance and stored in the ROM of the ECM 11.

  If the ECM 11 determines in step S4 that the engine rotational speed Ne is not higher than the F / C possible rotational speed Nefc, the ECM 11 prohibits the F / C because there is a possibility that an engine stall may occur when returning from the F / C. (Step S7), and the F / C determination control ends.

  If the ECM 11 determines in step S4 that the engine rotational speed Ne is greater than the F / C possible rotational speed Nefc, the process proceeds to step S5.

  In step S5, the ECM 11 determines whether any of the following F / C prohibition conditions is not satisfied. In the present embodiment, the following first to fourth conditions are respectively defined as F / C prohibition conditions.

[F / C prohibition conditions]
The vehicle speed V is less than the predetermined vehicle speed Vth (V <Vth) (first F / C prohibition condition)
The engine speed Ne is less than the predetermined speed Neth (Ne <Neth) (second F / C prohibition condition)
The accelerator opening Acc exceeds the predetermined value Accth (Acc> Accth) (third F / C prohibition condition)
-Within a predetermined time from the start of engine start (fourth F / C prohibition condition)

  The first to fourth F / C prohibition conditions described above are conditions under which it can be determined that it is preferable to prohibit the execution of F / C immediately after the engine is restarted in the EV mode.

  Specifically, in the first F / C prohibition condition, the predetermined vehicle speed Vth is a vehicle speed that serves as a reference for whether or not the clutch 26 can be smoothly connected immediately after the engine restart in the EV mode. For example, it is set to 10 km / h. When the vehicle speed V is equal to or higher than the predetermined vehicle speed Vth, the clutch 26 cannot be smoothly connected, which easily leads to vibration of the vehicle. Therefore, when the first F / C prohibition condition is not satisfied, the execution of F / C is permitted to suppress the engine speed Ne. Thereby, the rotational speed difference between the engine rotational speed Ne and the rotational speed Ni of the input shaft 25A is reduced, and the clutch 26 can be smoothly connected.

  In the second F / C prohibition condition, the predetermined rotational speed Neth is a rotational speed that serves as a reference for whether or not the clutch 26 can be smoothly connected immediately after the engine restart in the EV mode. Set to 1500 rpm. When the engine rotational speed Ne is equal to or higher than the predetermined rotational speed Neth, the clutch 26 cannot be smoothly connected, which easily leads to vehicle vibration. Therefore, when the second F / C prohibition condition is not satisfied, the execution of F / C is permitted to suppress the engine speed Ne. Thereby, the rotational speed difference between the engine rotational speed Ne and the rotational speed Ni of the input shaft 25A is reduced, and the clutch 26 can be smoothly connected. The predetermined rotational speed Neth is set to a value that is at least larger than the F / C possible rotational speed Nefc used in step S4 described above. The predetermined vehicle speed Vth and the predetermined rotation speed Neth described above are not limited to the hourly speed and rotation speed described above.

  Further, in the third F / C prohibition condition, the predetermined value Accth is set to an accelerator opening at which it can be determined that the hybrid vehicle 1 is started by depressing the accelerator pedal. Further, in the fourth F / C prohibition condition, the predetermined time is set to a time during which it can be determined that the engine has just been restarted. Immediately after the engine restart, since the engine speed Ne is unstable, the execution of F / C is prohibited to stabilize the behavior of the engine speed Ne. The first to fourth F / C prohibition conditions in the present embodiment correspond to predetermined fuel cut prohibition conditions in the present invention.

  If the ECM 11 determines that any one of the first to fourth F / C prohibition conditions is not satisfied in step S5, the ECM 11 permits F / C (step S6), and F / C The judgment control is terminated.

  If the ECM 11 determines in step S5 that all of the first to fourth F / C prohibition conditions are satisfied, the ECM 11 prohibits the F / C (step S7) and ends the F / C determination control. Therefore, in this embodiment, even if there is a torque reduction request from the TCM 12 immediately after the engine is restarted in the EV mode, the F / C is set on condition that all the first to fourth F / C prohibition conditions are satisfied. Is prohibited.

  Thus, as shown in FIG. 5, the engine torque does not vary depending on whether or not the F / C is executed immediately after the engine is restarted in the EV mode. In this embodiment, since the F / C is prohibited immediately after the engine restart in the EV mode, the behavior of the engine torque immediately after the engine restart increases or decreases like the behavior of the engine torque indicated by the solid line in FIG. Unified to a small and stable engine torque behavior.

  As described above, when the engine 2 is restarted during the EV mode, the drive control apparatus according to the present embodiment specifically satisfies the first to fourth F / C prohibition conditions immediately after the engine restarts. Since F / C is prohibited on the condition that all the conditions are satisfied, the engine torque immediately after the engine restart does not vary, and the behavior of the engine torque immediately after the engine restart can be stabilized.

  Thereby, the drive control apparatus according to the present embodiment can suppress the occurrence of vehicle body vibration caused by the fluctuation of the engine torque immediately after the engine restart in the EV mode.

  In this embodiment, the first to fourth F / C prohibition conditions are adopted as the F / C prohibition conditions. However, any one of the first to fourth F / C prohibition conditions, or 2 One or three may be F / C prohibition conditions. When the number of F / C prohibition conditions is two or three, all combinations are included as combinations of the first to fourth F / C prohibition conditions.

  While embodiments of the invention have been disclosed, it will be apparent to those skilled in the art that changes may be made without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims.

1 Hybrid vehicle (vehicle)
2 Engine 3 Transmission 4 Motor generator (motor)
11 ECM (control unit)
12 TCM
20 ISG (Starter)
31 Accelerator opening detector 32 Vehicle speed detector 33 Engine rotational speed detector Ne Engine rotational speed Nefc F / C possible rotational speed Neth Predetermined rotational speed Tr Torque required value Tth Torque threshold Tfc Engine torque at F / C Tbl Combustion lower limit torque P Predetermined ratio V Vehicle speed Vth Predetermined vehicle speed Acc Accelerator opening Accth Predetermined value

Claims (4)

A drive control device for a vehicle that has a starter for starting an engine and travels by the driving force of at least one of the engine and the motor,
A control unit capable of performing fuel cut to stop fuel injection to the engine;
The control unit is provided with a condition that a predetermined fuel cut prohibition condition is satisfied when the engine is started by the start unit during an EV mode in which the operation of the engine is stopped and the motor can drive by the driving force. In addition, the drive control device for a vehicle is characterized in that the fuel cut is prohibited.   2. The vehicle drive control device according to claim 1, wherein the predetermined fuel cut prohibition condition is that an accelerator opening representing an operation amount of an accelerator pedal exceeds a predetermined value.   The vehicle drive control device according to claim 1, wherein the predetermined fuel cut prohibition condition is within a predetermined time from the start of starting of the engine.   The predetermined fuel cut prohibition condition is characterized in that a vehicle speed representing the speed of the vehicle is less than a predetermined vehicle speed, and an engine rotational speed representing the rotational speed of the engine is less than a predetermined rotational speed. Item 4. The vehicle drive control device according to any one of Item 3.

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