JP2017144858A - Hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely stop an engine if engine stop is required while enabling retreat travel using engine power if ENG-HV communication malfunction occurs.SOLUTION: A hybrid vehicle comprises: an engine; a first MG; an output shaft; a planetary gear mechanism connecting them; an engine ECU; and a hybrid ECU. The engine ECU operates the engine if a communication abnormality occurs, and stops the engine if an engine rotating speed falls out of a predetermined range and if an auxiliary-machine voltage decreases below a threshold value. If a communication abnormality occurs, the hybrid ECU controls the torque of the first MG such that the engine rotating speed is maintained at a value within a predetermined range. If engine stop is required, the hybrid ECU stops torque output of the first MG. If an engine rotating speed stays within a predetermined range after the torque output of the first MG is stopped, the hybrid ECU decreases the auxiliary-machine voltage below the threshold value.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a hybrid vehicle that uses a plurality of control devices for engine control, and more particularly, to engine stop control when communication between the plurality of control devices is not possible.

  Japanese Patent Laying-Open No. 2014-231244 (Patent Document 1) discloses a hybrid vehicle including an engine, a first rotating electrical machine coupled to the engine, and a second rotating electrical machine for driving. This hybrid vehicle includes an engine control device and a hybrid control device. The hybrid control device controls the first rotating electrical machine and the second rotating electrical machine, and outputs an engine command signal to the engine control device through communication with the engine control device. The engine control device controls the engine in accordance with an engine command signal received from the hybrid control device. When an abnormality occurs in communication with the engine control device, the hybrid control device stops the operation of the engine by cutting off a relay for supplying power to the fuel injection valve of the engine. Thus, even when an abnormality occurs in communication between the hybrid control device and the engine control device, the hybrid control device can directly stop the engine without performing communication with the engine control device.

JP 2014-231244 A

  If the operation of the engine is stopped when a communication abnormality occurs between the control devices as disclosed in Patent Document 1 described above, the vehicle cannot be retreated using the power of the engine. Therefore, it is desirable to operate the engine as much as possible even when communication is abnormal.

  As a countermeasure, for example, when a communication abnormality occurs between the control devices, the engine control device operates the engine, and the engine is stopped when the engine speed exceeds a predetermined value during the operation of the engine. The hybrid controller applies the torque of the first rotating electrical machine in the direction opposite to the engine torque to keep the engine rotational speed below a predetermined value, and outputs the torque output of the first rotating electrical machine when there is an engine stop request. It can be considered that the engine speed is increased to a value higher than a predetermined value by stopping. According to such a countermeasure, even when a communication abnormality occurs between the control devices, the hybrid control device uses the torque of the first rotating electrical machine to adjust the engine rotation speed to indirectly stop the engine. can do. Therefore, even when there is a communication abnormality between the control devices, it is possible to stop the engine when there is an engine stop request while enabling retreat travel using the power of the engine.

  However, with the above measures, even after the torque output of the first rotating electrical machine is stopped in response to the engine stop request, the engine rotation speed may not increase due to some factor, and the engine may not be stopped. For example, in addition to engine torque, friction torque acts on the rotation shaft of the engine. Therefore, when the engine torque and the friction torque are balanced after the torque output of the first rotating electrical machine is stopped, the engine The engine does not stop because the rotational speed does not increase and stagnates below a predetermined value.

  The present invention has been made in order to solve the above-described problems, and its object is to use an engine power saving when communication abnormality occurs between a plurality of control devices used for engine control. It is to stop the engine more reliably when there is an engine stop request while enabling traveling.

  A hybrid vehicle according to the present invention includes an engine, a first rotating electrical machine, an output shaft connected to drive wheels, a planetary gear mechanism that mechanically connects the engine, the first rotating electrical machine, and the output shaft, and an output shaft. DC connected between the second rotating electrical machine to be connected, the traveling battery for transferring power between the first rotating electrical machine and the second rotating electrical machine, the auxiliary power line, and the auxiliary power line and the traveling battery. A first controller connected to the DC / DC converter, the auxiliary power line and controlling the engine, and connected to the auxiliary power line to control the first rotating electric machine, the second rotating electric machine and the DC / DC converter, and the first A second control device that outputs an engine command signal to the first control device by communication with the control device.

  The first control device executes output control for operating the engine so as to maintain the output of the engine constant when an abnormality occurs in communication with the second control device, and the engine speed during execution of the output control. When the engine is out of the predetermined range, the engine is stopped. The second control device executes torque control for controlling the torque of the first rotating electrical machine so as to maintain the engine speed at a value within a predetermined range when an abnormality occurs in communication with the first control device, If there is an engine stop request during execution of torque control, the torque output of the first rotating electrical machine is stopped.

  The second control device controls the DC / DC converter so that the voltage of the auxiliary power line is lower than the threshold when the engine rotation speed stays within a predetermined range after stopping the torque output of the first rotating electrical machine. The first control device stops the engine even when the engine rotational speed is not out of the predetermined range when the voltage of the auxiliary machine power line falls below the threshold during execution of the output control.

  According to the above configuration, when there is a communication abnormality with the second control device (hybrid control device), the first control device (engine control device) does not stop the engine but keeps the engine output constant. Operate the engine to maintain. Further, when the first control device stops the engine when the engine rotation speed is out of the predetermined range, the engine rotation speed is maintained at a value within the predetermined range by torque control by the second control device. Therefore, the engine is not stopped, and retreat travel using the power of the engine becomes possible.

  Furthermore, the second control device stops the torque control and stops the torque output of the first rotating electrical machine when there is an engine stop request. As a result, the torque of the first rotating electrical machine acting in the direction opposite to the engine torque is eliminated, and the engine rotation speed is increased by the action of the engine torque. Accordingly, when the engine rotation speed exceeds the upper limit value of the predetermined area (out of the predetermined area), the first control device stops the engine. As described above, even when a communication abnormality occurs, the second control device can indirectly stop the engine by adjusting the engine rotation speed using the torque of the first rotating electrical machine.

  Further, the second control device controls the DC / DC converter so that the voltage of the auxiliary power line is lower than the threshold when the engine rotation speed stays within a predetermined range after stopping the torque output of the first rotating electrical machine. To do. The first control device stops the engine even when the engine rotation speed is not out of the predetermined range when the voltage of the auxiliary machine power line falls below the threshold value. Therefore, even if the engine speed does not increase due to some factor such as engine friction after the torque output of the first rotating electrical machine is stopped, the second control device causes the DC / DC converter to stay in the predetermined range. By controlling and lowering the voltage of the auxiliary power line, the engine can be stopped more reliably.

  As a result, when there is an abnormality in communication between the first control device and the second control device, the engine is stopped more reliably when there is an engine stop request while enabling retreat travel using the engine power. Can be made.

1 is an overall block diagram (part 1) of a vehicle. FIG. 5 is a first diagram illustrating an example of states of an engine, a first MG, and a second MG in a collinear diagram of a planetary gear mechanism. FIG. 8 is a second diagram illustrating an example of states of the engine, the first MG, and the second MG in a collinear diagram of the planetary gear mechanism. FIG. 10 is a third diagram illustrating an example of states of the engine, the first MG, and the second MG in a collinear diagram of the planetary gear mechanism. FIG. 6 is a (fourth) diagram illustrating an example of states of the engine, the first MG, and the second MG in an alignment chart of a planetary gear mechanism. It is a flowchart (the 1) which shows the process sequence of engine ECU. It is a flowchart (the 1) which shows the process sequence of hybrid ECU. FIG. 3 is an overall block diagram (part 2) of the vehicle. It is a flowchart (the 2) which shows the process sequence of engine ECU. It is a flowchart (the 2) which shows the process sequence of hybrid ECU.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Vehicle configuration>
FIG. 1 is an overall block diagram of a vehicle 1 according to the present embodiment. The vehicle 1 includes an engine 100, a first MG (Motor Generator) 200, a planetary gear mechanism 300, a second MG 400, an output shaft 500, drive wheels 510, a PCU (Power Control Unit) 600, a battery for traveling. 700 and an SMR (System Main Relay) 710. The vehicle 1 further includes an engine ECU (Electronic Control Unit) 30 and a hybrid ECU 40.

  Vehicle 1 is a hybrid vehicle that travels using the power of at least one of engine 100 and second MG 400. During normal travel, vehicle 1 performs motor travel that uses the power of second MG 400 without using the power of engine 100 and hybrid travel (HV (Hybrid Vehicle) travel) that uses the power of both engine 100 and second MG 400. The driving mode can be switched between.

  The engine 100 burns fuel and outputs power. First MG 200 and second MG 400 are AC rotating electrical machines, and function as both a motor and a generator.

  The planetary gear mechanism 300 is a single pinion type planetary gear mechanism. The planetary gear mechanism 300 is not necessarily limited to the single pinion type, and may be a double pinion type, for example.

  The planetary gear mechanism 300 includes a sun gear 310 (hereinafter also referred to as “sun gear S”), a ring gear 320 (hereinafter also referred to as “ring gear R”), and a pinion gear 340 (hereinafter referred to as “pinion gear P”) that meshes with the sun gear S and the ring gear R. And a carrier 330 (hereinafter also referred to as “carrier C”) that holds the pinion gear P in a freely rotating and revolving manner.

  Carrier C is connected to engine 100. Sun gear S is connected to first MG 200. Ring gear R is coupled to output shaft 500. The output shaft 500 is connected to the left and right drive wheels 510 via a differential gear. Second MG 400 is directly connected to output shaft 500. Therefore, the ring gear R, the second MG 400, the output shaft 500, and the drive wheel 510 rotate in synchronization.

  Hereinafter, the rotational speed of the engine 100 is “engine rotational speed Ne”, the rotational speed of the first MG 200 is “first MG rotational speed Nm1”, the rotational speed of the second MG 400 is “second MG rotational speed Nm2”, and the rotational speed of the output shaft 500 May be described as “vehicle speed V”. Further, the output torque of engine 100 may be referred to as “engine torque Te”, the output torque of first MG 200 as “first MG torque Tm1”, and the output torque of second MG 400 as “second MG torque Tm2”. Further, the output power of engine 100 may be described as “engine power Pe”, and the output power of second MG 400 may be described as “second MG power Pm2”.

  FIG. 2 is a collinear diagram of the planetary gear mechanism 300 showing an example of the states of the engine 100, the first MG 200, and the second MG 400 during normal operation. In the collinear diagram of the planetary gear mechanism 300, the sun gear S, the carrier C, and the ring gear R of the planetary gear mechanism 300 are indicated by vertical lines, and their intervals are set to intervals corresponding to the gear ratio of the planetary gear mechanism 300. It is the figure which made the up-down direction of the line the rotation direction, and showed the position in the up-down direction as the rotation speed. Since planetary gear mechanism 300 according to the present embodiment is of a single pinion type, sun gear S coupled to first MG 200 is represented by a vertical line located at the left end in FIG. The carrier C is represented by a vertical line located at the center, and the ring gear R connected to the second MG 400 is represented by a vertical line located at the right end.

  The engine 100, the first MG 200, and the second MG 400 are mechanically coupled by the planetary gear mechanism 300, whereby the first MG rotational speed Nm1 (= the rotational speed of the sun gear S) and the engine rotational speed Ne (= the rotational speed of the carrier C). And the MG2 rotational speed Nm2 (= the rotational speed of the ring gear R) is a relationship that is connected by a straight line on the collinear chart (a relationship in which if any two rotational speeds are determined, the remaining one rotational speed is determined, hereinafter “collinear”). It is also referred to as “the relationship of the figure”.

  FIG. 2 illustrates a case where the vehicle 1 is traveling on the HV (moving forward). During HV traveling, engine 100 outputs engine torque Te in the positive direction to carrier C, and first MG 200 outputs first MG torque Tm1 in the negative direction to sun gear S. Thus, engine torque Te is transmitted to ring gear R using first MG torque Tm1 as a reaction force. The engine torque transmitted to the ring gear R using the first MG torque Tm1 as a reaction force (hereinafter also referred to as “engine direct delivery torque Tep”) acts on the ring gear R in the positive direction (forward direction).

  Further, second MG 200 outputs second MG torque Tm2 in the positive direction to ring gear R. Therefore, drive wheel 510 is rotated by a torque that is a combination of engine direct torque Tep and second MG torque Tm2.

  Returning to FIG. 1, PCU 600 converts high-voltage DC power supplied from battery 700 into AC power and outputs the AC power to first MG 200 and / or second MG 400. Thereby, first MG 200 and / or second MG 400 is driven. PCU 600 converts AC power generated by first MG 200 and / or second MG 400 into DC power and outputs the DC power to battery 700. Thereby, the battery 700 is charged. PCU 600 can also drive second MG 400 with the electric power generated by first MG 200.

  Battery 700 is a secondary battery that stores high-voltage (for example, about 200 V) DC power for driving first MG 200 and / or second MG 400. The battery 700 typically includes a nickel metal hydride battery and a lithium ion battery.

  SMR 710 is a relay for connecting battery 700 to PCU 600 and disconnecting battery 700 from PCU 600.

  Further, vehicle 1 is configured to supply power to an auxiliary load that operates at a lower voltage (for example, about 12 volts) than battery 700 for traveling, as an auxiliary power line 50, a DC / DC converter 800, And an auxiliary battery 900. The auxiliary machine load includes various electric devices that assist the traveling of the vehicle 1, such as an audio device, a lighting device, a car navigation device, and the like (not shown). The auxiliary machine load also includes the engine ECU 30 and the hybrid ECU 40.

  DC / DC converter 800 is electrically connected between power line connecting battery 700 and PCU 600 and auxiliary power line 50. DC / DC converter 800 steps down the voltage input from battery 700 or PCU 600 in accordance with a control signal from hybrid ECU 40 and outputs the voltage to auxiliary power line 50 (auxiliary battery 900 and auxiliary load). The normal value of the output voltage of DC / DC converter 800 (hereinafter also referred to as “DC / DC output voltage”) is, for example, about 14 volts.

  The auxiliary battery 900 has a positive terminal connected to the auxiliary power line 50 and a negative terminal connected to the ground. The auxiliary battery 900 is a power source for supplying electric power to the auxiliary load via the auxiliary power line 50, and includes, for example, a lead storage battery. The output voltage of auxiliary battery 900 is, for example, about 12 volts.

  Further, the vehicle 1 is provided with a plurality of sensors for detecting various information necessary for controlling the vehicle 1, such as the engine rotation speed sensor 10, the output shaft rotation speed sensor 15, the resolvers 21 and 22, and the accelerator position sensor 41. It is done. The engine rotation speed sensor 10 detects the engine rotation speed Ne and outputs the detection result to the engine ECU 30. The resolver 21 detects the first MG rotation speed Nm1 and outputs it to the hybrid ECU 40. The resolver 22 detects the second MG rotation speed Nm2, and outputs the detection result to the hybrid ECU 40. The output shaft rotational speed sensor 15 detects the rotational speed Np of the output shaft 500 as the vehicle speed V, and outputs the detection result to the hybrid ECU 40. The accelerator position sensor 41 detects the amount of accelerator pedal operation by the user, and outputs the detection result to the hybrid ECU 40.

  The engine ECU 30 and the hybrid ECU 40 each include a CPU (Central Processing Unit) and a memory (not shown), and execute predetermined arithmetic processing based on information stored in the memory and information from each sensor. Engine ECU 30 and hybrid ECU 40 are connected to auxiliary power line 50 and are operated by electric power supplied from auxiliary power line 50. Engine ECU 30 and hybrid ECU 40 are configured to be able to detect the voltage of power supplied from auxiliary power line 50 (hereinafter also referred to as “auxiliary voltage”).

  Hybrid ECU 40 is connected to engine ECU 30 via communication line 60 and communicates with engine ECU 30 to control overall vehicle 1 including engine 100, first MG 200, and second MG 400.

  More specifically, the hybrid ECU 40 calculates a driving force (hereinafter also referred to as “required driving force Preq”) requested by the user based on the accelerator pedal operation amount, the vehicle speed V, and the like. Hybrid ECU 40 generates an engine command signal, a first MG command signal, and a second MG command signal so that required driving force Preq is transmitted to drive wheels 510.

  Hybrid ECU 40 then outputs an engine command signal to engine ECU 30 through communication with engine ECU 30. Thereby, the engine ECU 30 controls the output of the engine 100 (specifically, the throttle opening, ignition timing, fuel injection amount, etc.) so that the engine power Pe becomes the power commanded by the engine command signal.

  Hybrid ECU 40 outputs the first MG command signal and the second MG command signal to PCU 600. Thus, PCU 600 operates to adjust the outputs (specifically, energization amount, etc.) of first MG 200 and second MG 400 according to the first MG command signal and second MG command signal from hybrid ECU 40, respectively.

  Engine ECU 30 outputs information indicating the state of engine 100 (for example, engine rotational speed Ne detected by engine rotational speed sensor 10) to hybrid ECU 40.

  Although FIG. 1 shows the hybrid ECU 40 as one unit, the hybrid ECU 40 can be divided into separate units for each function.

<Fail-safe operation when ENG-HV communication is abnormal>
In the vehicle 1 having the above-described configuration, when a communication abnormality between the engine ECU 30 and the hybrid ECU 40 (hereinafter, also referred to as “ENG-HV communication abnormality”) occurs, the engine 100 is appropriately set according to a user request. Can not be controlled. Specifically, the hybrid ECU 40 cannot output an engine command signal to the engine ECU 30. Further, the engine ECU 30 cannot receive an engine command signal from the hybrid ECU 40, and therefore cannot know how to control the engine 100.

  In such a case, in order to prevent the output of the engine 100 from becoming excessively high, it is conceivable that the engine ECU 30 stops the engine 100 uniformly (conventional equivalent). However, if engine 100 is stopped uniformly, there is a problem that retreat traveling of vehicle 1 using the power of engine 100 cannot be performed.

  Therefore, in the present embodiment, when ENG-HV communication abnormality occurs, the following retreat travel is performed by fail-safe operation.

  The engine ECU 30 executes control for operating the engine 100 so as to keep the output of the engine 100 constant. The target that is kept constant by this control may be the engine power Pe or the engine torque Te. Hereinafter, a case where “Pe constant control” for maintaining the engine power Pe at a predetermined fixed power Pfix is executed will be described as an example.

  Hybrid ECU 40 feedback-controls first MG torque Tm1 so as to maintain engine rotation speed Ne at a predetermined fixed rotation speed Nfix. Hereinafter, this control is also referred to as “Ne constant control”. The hybrid ECU 40 controls the output of the second MG 400 so as to satisfy the required driving force Preq on the assumption that the engine 100 is controlled by the above-mentioned Pe constant control and the first MG 200 is controlled by the above-described Ne constant control. To do.

  As described above, when the ENG-HV communication abnormality occurs, the engine ECU 30 operates the engine 100 by Pe constant control, but the hybrid ECU 40 has an engine stop request due to the influence of the ENG-HV communication abnormality (the engine 100 It is impossible to output an engine stop command to the engine ECU 30.

  In view of such a problem, the engine ECU 30 stops the Pe constant control and stops the engine 100 when the engine rotational speed Ne deviates from a predetermined range during the Pe constant control. Here, the “predetermined range” is an upper limit value obtained by adding the predetermined value α to the fixed rotational speed Nfix from the lower limit value Nmin (= Nfix−α) obtained by subtracting the predetermined value α (α> 0) from the fixed rotational speed Nfix. The range is up to Nmax (= Nfix + α).

  When there is an abnormality in communication with engine ECU 30 and there is an engine stop request, hybrid ECU 40 stops Ne constant control and stops the output of first MG torque Tm1. When the engine speed Ne increases due to the stop of the output of the first MG torque Tm1 and exceeds the upper limit value Nmax of the predetermined range, the engine ECU 30 stops the engine 100. As a result, even when the ENG-HV communication abnormality occurs, the hybrid ECU 40 can indirectly stop the engine 100 by adjusting the engine rotational speed Ne using the first MG torque Tm1.

  FIG. 3 is a diagram illustrating an example of states of the engine 100, the first MG 200, and the second MG 400 during fail-safe operation due to the ENG-HV communication abnormality in a collinear diagram of the planetary gear mechanism 300.

  As described above, when the ENG-HV communication abnormality occurs, the engine power Pe is maintained at the fixed power Pfix by the Pe constant control, and the engine rotation speed Ne is fixed by the Ne constant control (feedback control of the first MG torque Tm1). The rotational speed Nfix is maintained. At this time, the first MG torque Tm1 acts in the negative direction (the direction opposite to the engine torque Te) in order to suppress an increase in the engine rotation speed Ne due to the engine torque Te.

  The second MG torque Tm2 is controlled so as to satisfy the required driving force Preq on the assumption that the engine 100 is operated by Pe constant control. When the engine power Pe is deficient below the engine required power due to the engine 100 being operated with constant Pe control, the deficiency is compensated by the second MG power Pm2. As a result, even when ENG-HV communication abnormality occurs, the vehicle 1 can be retreated while satisfying the required driving force Preq with the engine power Pe and the second MG power Pm2.

  FIG. 4 is a diagram illustrating an example of states of the engine 100, the first MG 200, and the second MG 400 when the engine stop request is generated during the fail-safe operation due to the ENG-HV communication abnormality in the alignment chart of the planetary gear mechanism 300. is there.

  When there is no engine stop request, as described above, the engine rotational speed Ne is maintained at the fixed rotational speed Nfix by Ne constant control (see the solid line). At this time, the first MG torque Tm1 acts in the negative direction (the direction opposite to the engine torque Te) in order to suppress an increase in the engine rotation speed Ne due to the engine torque Te.

  When an engine stop request is generated during execution of the Ne constant control, the hybrid ECU 40 stops the execution of the Ne constant control and stops the output of the first MG torque Tm1. As a result, the first MG torque Tm1 acting in the direction opposite to the engine torque Te is eliminated, and the engine rotation speed Ne increases due to the action of the engine torque Te. As a result, the engine ECU 30 stops the engine 100 when the engine rotational speed Ne exceeds the upper limit value Nmax of the predetermined range (see the alternate long and short dash line). As a result, when the engine rotation speed Ne decreases to 0 (see the two-dot chain line), the retreat travel by motor travel is performed.

<DC / DC converter control when ENG-HV communication is abnormal>
As described above, the hybrid ECU 40 stops the output of the first MG torque Tm1 acting in the direction opposite to the engine torque Te when the engine stop request is generated during the fail safe operation due to the ENG-HV communication abnormality. To do. Thus, when engine speed Ne increases to a value higher than upper limit value Nmax of the predetermined range, engine 100 is stopped by engine ECU 30.

  However, even if the hybrid ECU 40 stops outputting the first MG torque Tm1, the engine speed Ne may not increase due to some factor, and the engine 100 may not be stopped.

  FIG. 5 shows an example of the states of the engine 100, the first MG 200, and the second MG 400 when the engine rotation speed Ne is not increased due to the influence of engine friction after the output of the first MG torque Tm1 is stopped. It is a figure shown to an alignment chart.

  Not only engine torque Te but also friction torque of engine 100 acts on the output shaft of engine 100. Therefore, after the hybrid ECU 40 stops the output of the first MG torque Tm1, when the engine torque Te and the friction torque are in a balanced state, the engine rotational speed Ne does not increase and stays within a predetermined range. The engine 30 is not stopped by the ECU 30.

  Although not shown in FIG. 5, since the rotational resistance of the first MG 200 acts in a direction that prevents the engine rotational speed Ne from increasing, the rotational resistance of the first MG 200 also stagnates in the predetermined range of the engine rotational speed Ne. Can be a factor.

  In view of such a point, the hybrid ECU 40 determines that the output voltage of the DC / DC converter 800 (hereinafter referred to as “DC / DC output voltage”) when the engine speed Ne stagnates within a predetermined range after the output of the first MG torque Tm1 is stopped. Is also reduced from a normal value (for example, about 14 volts) to a value lower than the normal value (for example, about 13 volts). As the DC / DC output voltage decreases, the voltage of the auxiliary power line 50 also decreases.

  Then, the engine ECU 30 monitors whether or not the accessory voltage has decreased below a normal value (hereinafter also referred to as “threshold”) during execution of the Pe constant control, and when the accessory voltage has decreased below the threshold. Even if the engine rotational speed Ne stagnates within a predetermined range, the Pe constant control is stopped and the engine 100 is stopped. Thereby, even if the engine speed Ne does not increase due to some factor such as engine friction after the output of the first MG torque Tm1 is stopped, the engine 100 can be stopped. As a result, when the ENG-HV communication abnormality occurs, the engine 100 can be stopped more reliably when there is an engine stop request while enabling the retreat travel using the power of the engine 100.

<Control flow when ENG-HV communication is abnormal>
Hereinafter, the processing procedure when engine ECU30 and hybrid ECU40 perform the above-mentioned control is demonstrated using a flowchart.

  FIG. 6 is a flowchart showing a processing procedure performed by engine ECU 30 when ENG-HV communication is abnormal. This flowchart is repeatedly executed at a predetermined cycle.

  In step (hereinafter, step is abbreviated as “S”) 10, engine ECU 30 determines whether a communication abnormality with hybrid ECU 40 has occurred. For example, engine ECU 30 determines that a communication abnormality with hybrid ECU 40 has occurred when information from hybrid ECU 40 cannot be received continuously for a predetermined time.

  If communication abnormality with hybrid ECU 40 has not occurred (NO in S10), engine ECU 30 ends the process. In this case, engine ECU 30 controls engine 100 in accordance with an engine command signal received from hybrid ECU 40.

  On the other hand, when communication abnormality with hybrid ECU 40 has occurred (YES in S10), engine ECU 30 performs fail-safe operation after S11.

  Specifically, in S11, engine ECU 30 determines whether or not fuel supply to engine 100 is stopped (fuel cut is in progress).

  If the fuel is being cut (YES in S11), engine ECU 30 performs start control of engine 100 in S12 and S13. Specifically, the engine ECU 30 determines whether or not the engine speed Ne is higher than a lower limit value Nmin within a predetermined range in S12. If engine speed Ne is not higher than lower limit value Nmin of the predetermined range (NO in S12), engine ECU 30 ends the process. On the other hand, when engine rotation speed Ne is higher than lower limit value Nmin of the predetermined range (YES in S12), engine ECU 30 supplies fuel to engine 100 and starts engine 100 in S13. After starting the engine 100, the engine ECU 30 moves the process to S14.

  If the fuel is not being cut (NO in S11), that is, if fuel has already been supplied to engine 100, engine ECU 30 skips the processes of S12 and S13, and moves the process to S14.

  In S14, engine ECU 30 executes the above-mentioned Pe constant control. That is, engine ECU 30 operates engine 100 to maintain engine power Pe at a predetermined fixed power Pfix.

  Thereafter, in S15, engine ECU 30 determines whether or not a predetermined time has elapsed since a communication abnormality with hybrid ECU 40 has occurred. The predetermined time used for the process of S15 is such that the engine speed Ne changes from a value outside the predetermined range to a value within the predetermined range by the above-described constant Ne control by the hybrid ECU 40 (the process of S22 in FIG. 7 described later). Is set to the time required for.

  If the predetermined time has not elapsed since the occurrence of the communication abnormality (NO in S15), the engine ECU 30 may not once converge within the predetermined range after the occurrence of the communication abnormality. , S16 and S17 are skipped, and Pe constant control is continued in S18.

  On the other hand, if the predetermined time has elapsed since the occurrence of the communication abnormality (YES in S15), the engine speed Ne is considered to have converged within the predetermined range at least once after the occurrence of the communication abnormality. In S16, the ECU 30 determines whether or not the engine rotation speed Ne exceeds an upper limit value Nmax within a predetermined range. This process is a process for the engine ECU 30 to determine whether or not the hybrid ECU 40 determines that there is an engine stop request using the engine speed Ne as a parameter (see S24 and S25 in FIG. 7 described later).

  When engine speed Ne exceeds upper limit value Nmax (YES in S16), hybrid ECU 40 determines that there is an engine stop request and stops the output of first MG torque Tm1 (S24 and S25 in FIG. 7 described later). Therefore, the engine ECU 30 stops the Pe constant control and stops the fuel supply to the engine 100 in S19. Thereby, engine 100 is stopped.

  On the other hand, when engine rotation speed Ne does not exceed upper limit value Nmax (NO in S16), engine ECU 30 determines in S17 whether or not the auxiliary machine voltage is lower than the threshold value. This process is a process for the engine ECU 30 to determine whether or not the hybrid ECU 40 determines that there is an engine stop request using the auxiliary machine voltage as a parameter (see S24 and S28 in FIG. 7 described later).

  When the auxiliary machine voltage is lower than the threshold value (YES in S17), hybrid ECU 40 determines that there is an engine stop request and reduces the DC / DC output voltage (see S24 and S28 in FIG. 7 described later). Therefore, the engine ECU 30 stops the Pe constant control and stops the fuel supply to the engine 100 in S19.

  On the other hand, when the auxiliary machine voltage is not lower than the threshold value (NO in S17), it is considered that hybrid ECU 40 determines that there is no engine stop request (NO in S24 of FIG. 7 described later). The engine ECU 30 continues the Pe constant control in S18.

  FIG. 7 is a flowchart showing a processing procedure performed by the hybrid ECU 40 when the ENG-HV communication is abnormal. This flowchart is repeatedly executed at a predetermined cycle.

  In S20, hybrid ECU 40 determines whether or not a communication abnormality with engine ECU 30 has occurred. For example, hybrid ECU 40 determines that communication abnormality with engine ECU 30 has occurred when information from engine ECU 30 cannot be received continuously for a predetermined time.

  When communication abnormality with engine ECU 30 has not occurred (NO in S20), hybrid ECU 40 ends the process. In this case, the hybrid ECU 40 controls the first MG 200 and the second MG 400 so as to satisfy the required driving force Preq on the assumption that the engine power Pe is a power according to the engine command signal (engine required power).

  On the other hand, when communication abnormality with engine ECU 30 has occurred (YES in S20), hybrid ECU 40 performs a fail-safe operation after S21.

  Specifically, in S21, hybrid ECU 40 determines whether or not engine rotation speed Ne is 0 (whether or not engine 100 is not rotating). When the ENG-HV communication abnormality occurs, the hybrid ECU 40 cannot acquire information on the engine rotational speed Ne from the engine ECU 30, but the first MG rotational speed Nm1 detected by the resolvers 21 and 22 respectively. The engine rotational speed Ne can be calculated from the nomographic relationship using the second MG rotational speed Nm2.

  When engine speed Ne is not 0 (NO in S21), that is, when engine 100 is rotating, hybrid ECU 40 executes the above-described Ne constant control in S22. That is, hybrid ECU 40 feedback-controls first MG torque Tm1 so as to maintain engine rotation speed Ne at a predetermined fixed rotation speed Nfix. When the ENG-HV communication is abnormal, the engine 100 generates the forward engine torque Te by the constant Pe control. Therefore, the first MG torque Tm1 is opposite to the engine torque Te in order to suppress the increase in the engine rotational speed Ne. It acts in the direction, that is, in the negative direction (see FIGS. 3 and 4 above).

  In S23, the hybrid ECU 40 controls the second MG torque Tm2 so as to satisfy the required driving force Preq on the assumption that the engine power is maintained at the fixed power Pfix by the Pe constant control described above.

  In S24, hybrid ECU 40 determines whether or not there is an engine stop request. For example, the hybrid ECU 40 determines that there is an engine stop request when the required driving force Preq drops below a predetermined value and when an abnormality of another control system occurs. If there is no engine stop request (NO in S24), hybrid ECU 40 ends the process.

  If there is an engine stop request (YES in S24), the hybrid ECU 40 stops the Ne constant control and sets the first MG torque in S25 so that the engine speed Ne is higher than the upper limit value Nmax of the predetermined range. Stop the output of Tm1.

  After stopping the output of the first MG torque Tm1, the hybrid ECU 40 determines in S26 whether or not the engine rotational speed Ne has exceeded an upper limit value Nmax within a predetermined range. Note that, similarly to the process of S21 described above, the hybrid ECU 40 calculates the engine rotational speed Ne from the alignment chart using the first MG rotational speed Nm1 and the second MG rotational speed Nm2 detected by the resolvers 21 and 22, respectively. be able to.

  When engine speed Ne exceeds upper limit value Nmax of the predetermined range (YES in S26), engine ECU 30 is considered to stop engine 100 (see S16 and S19 in FIG. 6 described above), so hybrid ECU 40 Ends the process.

  On the other hand, if engine rotation speed Ne does not exceed upper limit value Nmax of the predetermined range (YES in S26), in S27, hybrid ECU 40 determines whether a predetermined time has elapsed since the output of first MG torque Tm1 was stopped. Determine whether or not. The predetermined time used in the process of S27 is set to a time required for the engine rotation speed Ne to increase from a value within the predetermined range to a value exceeding the upper limit value of the predetermined range by stopping the output of the first MG torque Tm1.

  If the predetermined time has not elapsed since the output of first MG torque Tm1 was stopped (NO in S27), hybrid ECU 40 returns the process to S26.

  If the engine speed Ne does not exceed the upper limit value Nmax of the predetermined range even though a predetermined time has elapsed after the output of the first MG torque Tm1 is stopped (NO in S27), the output of the first MG torque Tm1 is Even after stopping, it is considered that the engine rotational speed Ne does not increase due to some factor such as engine friction and is still within a predetermined range. Therefore, the hybrid ECU 40 sets the DC / DC output voltage to a normal value (for example, 14 The voltage is reduced to a value (for example, about 13 volts) lower than the normal value. As a result, the auxiliary machine voltage falls below the threshold value, and engine 100 is stopped by engine ECU 30 (see S17 and S19 in FIG. 6 described above).

  As described above, when the ENG-HV communication abnormality occurs, the engine ECU 30 does not stop the engine 100 but operates the engine 100 by Pe constant control. Further, the engine ECU 30 stops the engine 100 when the engine rotational speed Ne exceeds the upper limit value Nmax of the predetermined range (when it deviates from the predetermined range), and the engine rotational speed Ne is controlled to be constant Ne by the hybrid ECU 40 ( The fixed rotational speed Nfix that is a value within a predetermined range is maintained by the feedback control of the first MG torque Tm1). Therefore, the engine 100 is not stopped, and retreat traveling using the power of the engine becomes possible.

  Furthermore, when there is an engine stop request during execution of the Ne constant control, the hybrid ECU 40 stops the Ne constant control and stops the output of the first MG torque Tm1. As a result, the first MG torque Tm1 acting in the direction opposite to the engine torque Te is eliminated, and the engine rotation speed Ne increases due to the action of the engine torque Te. As a result, the engine ECU 30 stops the engine 100 when the engine rotational speed Ne exceeds the upper limit value of the predetermined range (out of the predetermined range). Thus, even when the ENG-HV communication abnormality occurs, the hybrid ECU 40 can indirectly stop the engine 100 by adjusting the engine rotational speed Ne using the first MG torque Tm1.

  Further, hybrid ECU 40 controls DC / DC converter 800 such that the auxiliary machine voltage falls below the threshold when engine rotation speed Ne stagnates within a predetermined range after the output of first MG torque Tm1 is stopped. The engine ECU 30 stops the engine 100 when the auxiliary machine voltage falls below the threshold even if the engine rotational speed Ne is stagnant within a predetermined range. Therefore, even if the engine rotation speed Ne does not increase due to some factor such as engine friction after the output of the first MG torque Tm1 is stopped, the hybrid ECU 40 controls the DC / DC converter 800 to decrease the auxiliary machine voltage. Thus, the engine can be stopped more reliably.

  As a result, when ENG-HV communication abnormality occurs, the engine can be stopped more reliably when there is an engine stop request while enabling retreat travel using the power of the engine 100.

<Modification>
In the above-described embodiment, the configuration in which the communication between the engine ECU 30 and the hybrid ECU 40 is performed through one communication path (communication line 60) is shown, but the communication between the engine ECU 30 and the hybrid ECU 40 is performed by a plurality of communication paths. You may make it the structure performed by.

  FIG. 8 is an overall block diagram of a vehicle 1A according to this modification. The vehicle 1A shown in FIG. 8 is different from the vehicle 1 shown in FIG. 1 in that the engine ECU 30 and the hybrid ECU 40 are connected by a communication line 70 in addition to the communication line 60. Since the other configuration of vehicle 1A is the same as that of vehicle 1 described above, detailed description thereof will not be repeated here.

  When the engine ECU 30 and the hybrid ECU 40 communicate with each other, the communication line 60 is used as a main bus, and the communication line 70 is used as a sub-bus. The hybrid ECU 40 normally communicates with the engine ECU 30 using the main bus (communication line 60). The hybrid ECU 40 communicates with the engine ECU 30 using the sub-bus (communication line 70) when the ENG-HV communication abnormality occurs (that is, when abnormality occurs in communication via the main bus). Therefore, even when ENG-HV communication abnormality occurs (that is, when abnormality occurs in communication via the main bus), hybrid ECU 40 indicates that engine 100 should be stopped (hereinafter also referred to as “stop information”). Can be transmitted to the engine ECU 30 using a sub-bus. Here, the “stop information” may be a signal requesting fuel cut to the engine 100, a signal indicating that the vehicle 1A is in a stopped state (a signal indicating that the shift range is a parking range, Alternatively, a signal indicating that the vehicle speed V is 0) may be used.

  FIG. 9 is a flowchart showing a processing procedure performed by the engine ECU 30 according to this modification when the ENG-HV communication is abnormal. The flowchart of FIG. 9 is obtained by adding step S40 to the flowchart of FIG. Since the processing contents of the steps given the same numbers as the steps shown in FIG. 6 have already been described, detailed description will not be repeated here.

  If the engine rotation speed Ne does not exceed the upper limit value Nmax during execution of the Pe constant control (S14) (NO in S16), the engine ECU 30 has received the above stop information via the subbus in S40. Determine whether. When the above stop information is received via the subbus (YES in S40), engine ECU 30 stops the Pe constant control in S19 and stops the fuel supply to engine 100. If the above stop information has not been received via the sub-bus (NO in S40), engine ECU 30 moves the process to S17.

  FIG. 10 is a flowchart showing a processing procedure performed by the hybrid ECU 40 according to this modification when the ENG-HV communication is abnormal. Note that the flowchart of FIG. 10 is obtained by adding step S50 to the flowchart of FIG. 7 described above. Since the processing contents of the steps given the same numbers as the steps shown in FIG. 7 have already been described, detailed description will not be repeated here.

  When the predetermined time has elapsed since the hybrid ECU 40 stopped outputting the first MG torque Tm1 in response to the engine stop request, the hybrid ECU 40 does not exceed the upper limit value Nmax of the predetermined range (in S27). NO), at S50, the stop information is transmitted to engine ECU 30 via the sub-bus. Thereafter, the hybrid ECU 40 moves the process to S28.

  As described above, when one communication path (main bus) is abnormal, stop information is transmitted from the hybrid ECU 40 to the engine ECU 30 using another communication path (sub bus) that can be communicated. Also good. Thereby, when there is an engine stop request, the engine can be stopped more reliably.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1, 1A vehicle, 10 engine rotational speed sensor, 15 output shaft rotational speed sensor, 21, 22 resolver, 30 engine ECU, 40 hybrid ECU, 41 accelerator position sensor, 50 auxiliary power line, 60, 70 communication line, 100 engine, 200 1st MG, 300 planetary gear mechanism, 310 sun gear, 320 ring gear, 330 carrier, 340 pinion gear, 400 2nd MG, 500 output shaft, 510 drive wheel, 600 PCU, 700 battery, 710 SMR, 800 converter, 900 auxiliary battery.

Claims (1)

A hybrid vehicle,
Engine,
A first rotating electrical machine;
An output shaft connected to the drive wheel;
A planetary gear mechanism that mechanically connects the engine, the first rotating electrical machine, and the output shaft;
A second rotating electrical machine connected to the output shaft;
A battery for traveling that exchanges power between the first rotating electrical machine and the second rotating electrical machine;
Auxiliary power line,
A DC / DC converter provided between the auxiliary power line and the traveling battery;
A first controller connected to the auxiliary power line and controlling the engine;
Connected to the auxiliary power line, controls the first rotating electrical machine, the second rotating electrical machine, and the DC / DC converter, and outputs an engine command signal to the first control device through communication with the first control device. A second control device,
The first control device executes output control for operating the engine so as to keep the output of the engine constant when an abnormality occurs in communication with the second control device, and executes the output control. The engine is stopped when the engine speed deviates from the predetermined range during
The second control device is a torque that controls the torque of the first rotating electrical machine so as to maintain the engine rotation speed at a value within the predetermined range when an abnormality occurs in communication with the first control device. Control, and when there is a request to stop the engine during execution of the torque control, the torque output of the first rotating electrical machine is stopped,
When the engine rotation speed stagnates within the predetermined range after stopping the torque output of the first rotating electrical machine, the second control device is configured to reduce the DC / DC voltage so that the voltage of the auxiliary power line is lower than a threshold value. Control the DC converter,
The first control device stops the engine even when the voltage of the auxiliary machine power line falls below the threshold during execution of the output control, even when the engine speed is not out of the predetermined range. A hybrid vehicle.

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