JP6040961B2 - Vehicle control system - Google Patents

Description

  The present invention relates to a vehicle control system that controls a hybrid vehicle using a power split mechanism.

  Conventionally, a technique for forcibly stopping a motor that drives a throttle valve when an electronic throttle valve is not normally controlled by a microcomputer is known (see, for example, Patent Document 1).

JP 2011-127546 A

  In a hybrid vehicle using a power split mechanism, the axle is driven mainly by a motor. For this reason, when an abnormality occurs in the microcomputer that controls the hybrid vehicle, the motor is forcibly stopped.

  However, in a hybrid vehicle using a power split mechanism, two motors and an engine are connected via the power split mechanism. For this reason, if the engine is rotating when the motor for driving the motor is forcibly stopped, the rotational speed of the other motor becomes too large depending on the rotational speed of the engine. Could be damaged.

  The present invention has been made in view of these problems, and an object of the present invention is to suppress damage to a motor due to over-rotation in a hybrid vehicle using a power split mechanism.

The vehicle control system of the present invention made to achieve the above object includes a hybrid vehicle control device, a motor control device, an engine control device, and a stopping means.
In the vehicle control system of the present invention, the hybrid vehicle control device has a power split mechanism that splits and transmits engine power to the first motor generator and the axle, and a hybrid vehicle that has a second motor generator that transmits power to the axle. To control. The motor control device controls the first motor generator and the second motor generator, and the engine control device controls the engine. The stop means forcibly stops the second motor generator when an abnormality occurs in the hybrid vehicle control device. The engine control device further includes engine rotation limiting means. Then, when the engine rotation restricting means is forcibly stopping the second motor generator by the stopping means and the rotation speed of the first motor generator is equal to or higher than a preset overspeed determination rotation speed, Control is performed to limit the rotational speed of the engine so that the rotational speed of the motor generator is less than the excessive rotational speed determination rotational speed.

  The vehicle control system of the present invention configured as described above forcibly stops the second motor generator when an abnormality occurs in the hybrid vehicle control device. For this reason, even if the second motor generator cannot be normally controlled due to an abnormality in the hybrid vehicle control device, it is possible to avoid a situation in which an excessive driving force is transmitted from the second motor generator to the axle.

  Furthermore, in the vehicle control system of the present invention, when the second motor generator is forcibly stopped by the stopping means and the rotation speed of the first motor generator is equal to or higher than the overspeed determination rotation speed, the engine rotation speed is increased. Control to limit. For this reason, in the first motor generator to which the engine power is transmitted through the power split mechanism, the rotation speed of the first motor generator exceeds the over-rotation determination rotation speed due to the increase in the engine rotation speed. Generation | occurrence | production can be suppressed and damage to the 1st motor generator by excessive rotation can be suppressed.

1 is a block diagram showing a configuration of a vehicle control system 1. FIG. It is a top view which shows the structure of the drive system of the vehicle by which the vehicle control system 1 is mounted. FIG. 3 is a collinear diagram of a power split mechanism 30. It is a flowchart which shows the procedure of a monitoring process. It is a flowchart which shows the procedure of a rotation limitation process. 3 is a timing chart showing the operation of the vehicle control system 1.

Embodiments of the present invention will be described below with reference to the drawings.
A vehicle control system 1 according to the present embodiment is mounted on a hybrid vehicle, and as shown in FIG. 1, a hybrid vehicle electronic control device 2, an engine electronic control device 3, a motor generator electronic control device 4, An inverter 5 is provided. Hereinafter, the hybrid vehicle electronic control device 2 is referred to as an HVECU (Hybrid Vehicle Electronic Control Unit) 2. The engine electronic control unit 3 is referred to as an engine ECU 3. The motor generator electronic control unit 4 is referred to as MGECU (Motor Generator Electronic Control Unit) 4.

The HVECU 2 includes a microcomputer 11 (hereinafter referred to as a microcomputer 11) and a monitoring circuit 12.
The microcomputer 11 includes a CPU, a ROM, a RAM, an I / O, a bus line that connects these components, and the like, and is connected to the engine ECU 3 and the MGECU 4 via a vehicle LAN so as to be able to perform data communication.

  The microcomputer 11 detects the driving state of the vehicle using the accelerator pedal depression amount by the driver, the brake pedal operation by the driver, the traveling speed of the vehicle, and the like. Based on the detected operating state, the microcomputer 11 requests a torque required for the engine 21 (hereinafter referred to as a required engine torque) and a torque required for the motor generators 22 and 23 (hereinafter referred to as a required motor torque). Is calculated. Thereafter, the microcomputer 11 transmits a request engine torque signal indicating the calculated magnitude of the requested engine torque to the engine ECU 3 and transmits a request motor torque signal indicating the calculated magnitude of the requested motor torque to the MGECU 4.

  The monitoring circuit 12 obtains determination information set in advance to determine whether the microcomputer 11 is in a normal state or an abnormal state from the microcomputer 11, and when the microcomputer 11 determines that the microcomputer 11 is in an abnormal state, A stop signal for forcibly stopping 5 is output to the inverter 5.

When receiving a stop signal from the monitoring circuit 12, the inverter 5 outputs this stop signal to the MGECU 4.
The engine ECU 3 calculates an intake air amount, a fuel injection amount, an ignition timing, and the like necessary for realizing the required engine torque indicated by the required engine torque signal from the HVECU 2. Based on the calculation result, the engine ECU 3 controls various actuators such as a throttle motor, an injector, and an ignition plug to operate the engine 21.

  The MGECU 4 operates the motor generators 22 and 23 by outputting a drive signal to the inverter 5 so as to realize the required motor torque indicated by the required motor torque signal from the HVECU 2. When MGECU 4 receives a stop signal from inverter 5, MGECU 4 transmits MG forced stop information indicating that motor generator 23 is in a forced stop state to engine ECU 3.

As shown in FIG. 2, engine 21 and motor generators 22 and 23 are connected to power split mechanism 30.
The power split mechanism 30 includes a planetary gear mechanism that includes a sun gear 31, a ring gear 32, and a planetary carrier 33.

  The crankshaft of the engine 21 is connected to the planetary carrier 33. The rotating shaft of motor generator 22 is connected to sun gear 31. The rotating shaft of the motor generator 23 is connected to the ring gear 32. Thus, the rotational driving force of the engine 21 is transmitted to the motor generator 22 connected to the sun gear 31 and the motor generator 23 connected to the ring gear 32 via the planetary carrier 33.

  Further, the ring gear 32 is connected to the axle 43 via a reduction gear mechanism 41 and a differential gear 42. For this reason, the rotational driving force of the engine 21 can be transmitted to the axle 43 by driving the engine 21. Similarly, by driving the motor generator 23, the rotational driving force of the motor generator 23 can be transmitted to the axle 43.

  For example, when starting the vehicle or traveling at a low speed, the motor generator 23 is driven while the engine 21 is stopped, so that the vehicle can be driven only by the power of the motor generator 23.

  Further, for example, during normal traveling of the vehicle, by operating the engine 21, the axle 43 can be driven to drive the vehicle, and the motor generator 22 can be driven to generate electric power. Then, by driving the motor generator 23 with the generated power, the power of the motor generator 23 can be added to the power of the engine 21 to drive the vehicle.

  As described above, the crankshaft of the engine 21 is connected to the planetary carrier 33, the rotation shaft of the motor generator 22 is connected to the sun gear 31, and the axle 43 is connected to the ring gear 32 via the reduction gear mechanism 41 and the differential gear 42. It is connected to. Therefore, the rotational speed of the engine 21 (hereinafter referred to as engine rotational speed Ne), the rotational speed of the motor generator 22 (hereinafter referred to as motor rotational speed Ng), and the rotational speed of the axle 43 (hereinafter referred to as axle rotational speed Nd). Changes so as to be located on the same straight line as shown in the alignment chart shown in FIG.

  Specifically, when the gear ratio between the engine 21 and the motor generator 22 is K when the gear ratio between the engine 21 and the axle 43 is 1, the engine speed Ne is expressed by the following equation (1). expressed.

Ne = (Ng + K × Nd) / (K + 1) (1)
Next, processing executed by the monitoring circuit 12 (hereinafter referred to as monitoring processing) will be described.
When the monitoring process is executed, the monitoring circuit 12 first determines in S10 whether or not the microcomputer 11 is in an abnormal state based on the determination information acquired from the microcomputer 11 as shown in FIG. Whether or not the state is abnormal can be determined by detecting the occurrence of a phenomenon such as “the actual driving torque is abnormally large with respect to the accelerator opening”.

  Here, when the microcomputer 11 is in a normal state (S10: NO), the monitoring process is temporarily ended, and the monitoring process is executed again from the process of S10. On the other hand, if the microcomputer 11 is in an abnormal state (S10: YES), a stop signal for forcibly stopping the inverter 5 is output to the inverter 5 in S20. Thereby, a stop signal is input to the inverter 5 and the inverter 5 is forcibly stopped.

Then, when the process of S20 ends, the monitoring process is temporarily ended, and the monitoring process is executed again from the process of S10.
Next, the procedure of the rotation restriction process executed by the engine ECU 3 will be described. The rotation limiting process is a process that is repeatedly executed during the operation of the engine ECU 3.

  When this rotation limiting process is executed, engine ECU 3 first determines in S100 whether motor generator 23 is in a stopped state, as shown in FIG. Specifically, when MG forced stop information is received from MGECU 4, it is determined that motor generator 23 is in a stopped state, and when MG forced stop information is not received, it is determined that motor generator 23 is not in a stopped state. To do.

  Here, when the motor generator 23 is not in a stopped state (S100: NO), the rotation limiting process is temporarily ended. On the other hand, when the motor generator 23 is in a stopped state (S100: YES), the maximum engine speed Nemax is calculated by the following equation (2) in S110. Here, X is the maximum rotation speed of the motor generator 22 (hereinafter referred to as the maximum motor rotation speed X). The following expression (2) is obtained by replacing the motor rotation speed Ng of the expression (1) with the motor maximum rotation speed X.

Nemax = (X + K × Nd) / (K + 1) (2)
In S120, it is determined whether or not the rotational speed of engine 21 (hereinafter referred to as engine rotational speed Ne) is equal to or higher than a rotational speed obtained by subtracting preset rotational speed limit determination rotational speed β from engine maximum rotational speed Nemax. To do. Note that the rotation limit determination rotation speed β is set in consideration of a margin until a component failure occurs. For example, the rotation limit is based on the criterion that “the reliability of the motor generator 22 does not decrease when Nemax>Ne> Nemax−β, but the reliability of the motor generator 22 decreases when Ne> Nemax”. Determination rotational speed β is set.

Note that a motor limit determination rotational speed X1, which will be described later, is calculated by the following equation (3).
(Nemax−β) = (X1 + K × Nd) / (K + 1) (3)
Here, when the engine speed Ne is less than the rotation speed obtained by subtracting the rotation limit determination rotation speed β from the engine maximum speed Nemax (S120: NO), the rotation limit process is temporarily ended. On the other hand, when the engine speed Ne is equal to or higher than the speed obtained by subtracting the rotation limit determination speed β from the engine maximum speed Nemax (S120: YES), the opening degree of the electronic throttle is reduced in S130. By executing a process for controlling the throttle motor, the engine speed Ne is reduced.

  After that, in S140, it is determined whether or not the engine speed Ne is equal to or higher than a speed obtained by adding a preset fuel cut determination speed α to the engine maximum speed Nemax. The fuel cut determination rotational speed α is set by applying a component failure margin or the like. For example, the fuel cut determination rotational speed α is set on the basis of “if Ne> Nemax + α, the motor generator 22 fails in a single shot, but if Ne> Nemax, the motor generator 22 only needs to be deteriorated”. Is done.

  Here, when the engine speed Ne is less than the speed obtained by adding the fuel cut determination speed α to the engine maximum speed Nemax (S140: NO), the rotation limiting process is temporarily ended. On the other hand, when the engine speed Ne is equal to or higher than the engine speed determined by adding the fuel cut determination speed α to the engine maximum speed Nemax (S140: YES), the engine is cut at S150 to execute the engine cut. Decrease the rotational speed Ne. Then, when the process of S150 ends, the rotation limiting process is temporarily ended.

Next, the specific example of operation | movement of the vehicle control system 1 comprised in this way is demonstrated.
As shown in FIG. 6, first, when the monitoring circuit 12 determines that the microcomputer 11 is in an abnormal state (see time t01 in “the state of the microcomputer 11”), the monitoring circuit 12 outputs a stop signal to the inverter 5 ( (See time t02 of “stop signal”).

  As a result, regardless of the magnitude of the requested motor torque from the HVECU 2 to the motor generator 23 (see the requested torque RQ1), the actual torque RT1 of the motor generator 23 decreases to 0 N · m (“torque of the motor generator 23”). Time t02 to t03).

  Thereafter, when the engine speed Ne becomes equal to or greater than (the engine maximum speed Nemax−the rotation limit determination rotation speed β) (see time “T04” of “Ne”), control for limiting the engine speed Ne (hereinafter, Ne limit control). (See arrow NC).

  As a result, regardless of the magnitude of the requested engine torque from the HVECU 2 to the engine 21 (see the requested torque RQ2), the actual torque RT2 of the engine 21 decreases, and the engine speed Ne becomes (the engine maximum speed Nemax-rotation). When the rotation speed is less than the limit determination rotation speed β) (see “Ne” time t05), the Ne limit control is terminated. Thereafter, every time the engine speed Ne becomes equal to or higher than (the engine maximum speed Nemax−the rotation limit determination rotation speed β) (see the times t06, t07, t08, t09, and t010 of “Ne”), the Ne limit control is performed. Executed.

  In the vehicle control system 1 configured as described above, the microcomputer 11 of the HVECU 2 splits and transmits the power of the engine 21 to the motor generator 22 and the axle 43, and the motor generator that transmits the power to the axle 43. 23 is controlled. Further, the MGECU 4 and the inverter 5 control the motor generator 22 and the motor generator 23, and the engine ECU 3 controls the engine 21. The monitoring circuit 12 and the inverter 5 of the HVECU 2 forcibly stop the motor generator 23 when an abnormality occurs in the microcomputer 11 of the HVECU 2. When the engine ECU 3 is forcibly stopping the motor generator 23 by the monitoring circuit 12 and the inverter 5 and the rotation speed of the motor generator 22 is equal to or higher than a preset motor limit determination rotation speed X1, the motor Control is performed to limit the rotational speed of the engine 21 so that the rotational speed of the generator 22 is less than the motor limit determination rotational speed X1 (S100 to S150).

  As a result, the vehicle control system 1 avoids occurrence of a situation in which an excessive driving force is transmitted from the motor generator 23 to the axle 43 even if the motor generator 23 cannot be normally controlled due to an abnormality of the microcomputer 11 of the HVECU 2. Can do. Furthermore, in the vehicle control system 1, the motor generator 22 to which the power of the engine 21 is transmitted via the power split mechanism 30 causes the rotation speed of the motor generator 22 to be the motor limit determination rotation speed due to the increase in the rotation speed of the engine 21. Generation | occurrence | production of the situation which becomes X1 or more can be suppressed, and the failure | damage of the motor generator 22 by overrotation can be suppressed.

  Further, the engine ECU 3 determines that the rotation speed of the motor generator 22 is equal to or higher than the motor limit determination rotation speed X1 when the rotation speed of the engine 21 is equal to or higher than (the engine maximum rotation speed Nemax−the rotation limit determination rotation speed β). Judgment is made (S120).

  As a result, it is possible to detect over-rotation of the motor generator 22 using the engine speed that is generally used for vehicle control. For this reason, it is not necessary to separately acquire information indicating the rotation speed of the motor generator 22 in order to detect excessive rotation of the motor generator 22, and the configuration of the vehicle control system 1 can be simplified.

  Further, the engine ECU 3 limits the rotational speed of the engine 21 by controlling the opening degree of the electronic throttle (S130). As a result, as the rotation speed of the motor generator 22 exceeds the motor limit determination rotation speed X1, the greater the rotation speed (hereinafter referred to as excess rotation speed), the smaller the opening degree of the electronic throttle is reduced. Control which restrict | limits the rotation speed of the engine 21 according to a number can be performed.

  Moreover, engine ECU3 restrict | limits the rotation speed of the engine 21 by fuel cut (S150). Since fuel supply to the engine 21 is suppressed by the fuel cut, the output of the engine 21 can be reliably reduced. Thereby, the rotation speed limit of the engine 21 can be more reliably executed.

  Further, when the engine speed Ne is equal to or higher than the speed obtained by adding the fuel cut determination speed α to the engine maximum speed Nemax (S140: YES), the engine ECU 3 limits the speed of the engine 21 by the fuel cut. (S150). On the other hand, when the engine ECU 3 is less than the rotation speed obtained by adding the fuel cut determination rotation speed α to the engine maximum rotation speed Nemax (S140: NO), the engine ECU 3 controls the opening degree of the electronic throttle to control the rotation speed of the engine 21. (S130).

  The engine speed limit amount due to fuel cut is larger than the engine speed limit amount due to control of the electronic throttle opening. For this reason, when the excess rotational speed is large, the fuel cut is used, while when the excessive rotational speed is not large, the control of the opening degree of the electronic throttle is used. Accordingly, an appropriate engine rotation limiting method can be employed.

  Further, the MGECU 4 and the engine ECU 3 are connected to each other so that data communication is possible. When the motor generator 23 is forcibly stopped by the monitoring circuit 12 and the inverter 5, the MGECU 4 transmits MG forcible stop information indicating the fact to the engine ECU 3. As a result, the engine ECU 3 does not need to obtain from the microcomputer 11 of the HVECU 2 in which an abnormality has occurred, whether or not the forced stop of the motor generator 23 is being executed, and the forced stop of the motor generator 23 is being executed. The reliability of determining whether or not there is can be improved.

  In the embodiment described above, the motor generator 22 is the first motor generator in the present invention, the motor generator 23 is the second motor generator in the present invention, the microcomputer 11 of the HVECU 2 is the hybrid vehicle control device in the present invention, the MGECU 4 and the inverter 5 are the main motor generator. The motor control device in the invention, the engine ECU 3 is the engine control device in the present invention, the monitoring circuit 12 and the inverter 5 are the stopping means in the present invention, the processing of S100 to S150 is the engine rotation limiting means in the present invention, and the motor limit determination rotational speed X1 is In the present invention, the overspeed determination engine speed (engine maximum speed Nemax−rotation restriction determination speed β) is an overspeed determination engine speed in the present invention, and the determination condition in S140 is an excess determination condition in the present invention.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, As long as it belongs to the technical scope of this invention, a various form can be taken.
For example, in the above-described embodiment, the engine maximum speed Nemax is calculated using the equation (2) derived based on the relationship shown by the alignment chart of FIG. In equation (2), the maximum engine speed Nemax is calculated using the axle speed Nd. However, as long as the rotational speed of the ring gear 32 can be derived, a rotational speed other than the axle rotational speed Nd may be used in Equation (2). For example, since the rotation shaft of the motor generator 23 is coupled to the ring gear 32, the engine maximum rotation speed Nemax may be calculated using the rotation speed of the motor generator 23.

  In the above embodiment, the control for limiting the engine speed is executed when the engine speed Ne is equal to or higher than the rotation speed obtained by subtracting the rotation limit determination rotation speed β from the maximum engine speed Nemax. However, the rotational speed of the motor generator 22 (motor rotational speed Ng) is directly measured, and when the motor rotational speed Ng is equal to or higher than the motor limit determination rotational speed X1, control for limiting the engine rotational speed may be executed. Good.

  In the above embodiment, the stop signal is output when the microcomputer 11 of the HVECU 2 is in an abnormal state. However, a stop signal may be output when the MGECU 4 is in an abnormal state.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle control system, 2 ... HVECU, 3 ... Engine ECU, 4 ... MGECU, 5 ... Inverter, 11 ... Microcomputer, 12 ... Monitoring circuit, 21 ... Engine, 22, 23 ... Motor generator, 30 ... Power split mechanism

Claims (3)

A power split mechanism (30) that splits and transmits the power of the engine (21) to the first motor generator (22) and the axle (43), and a second motor generator (23) that transmits the power to the axle. A hybrid vehicle control device (11) for controlling the hybrid vehicle;
Motor control devices (4, 5) for controlling the first motor generator and the second motor generator;
An engine control device (3) for controlling the engine;
Stop means (12, 5) for forcibly stopping the second motor generator when an abnormality occurs in the hybrid vehicle control device;
The engine control device
When the second motor generator is forcibly stopped by the stopping means and the rotational speed of the first motor generator is equal to or higher than a preset over-rotation determination rotational speed, the first motor generator Engine rotation limiting means (S100 to S150) for performing control to limit the rotation speed of the engine so that the rotation speed is less than the excessive rotation determination rotation speed ;
The engine rotation limiting means is
When the rotational speed of the first motor generator exceeds the over-rotation determination rotational speed is set as the excessive rotational speed, and the rotational speed of the first motor generator is equal to or higher than the over-rotation determination rotational speed, When a preset excess determination condition indicating that the excess rotational speed is large is satisfied, the engine speed is limited by fuel cut, and when the excess determination condition is not satisfied, the opening degree of the electronic throttle The vehicle control system is characterized in that the engine speed is limited by controlling the engine . The engine rotation limiting means is
The engine speed when the rotation speed of the first motor generator is equal to the overspeed determination engine speed is defined as the overspeed determination engine speed, and the engine speed is equal to or higher than the overspeed determination engine speed. In this case, it is determined that the rotational speed of the first motor generator is equal to or higher than the over-rotation determination rotational speed. The motor control device and the engine control device are connected to each other so that data communication is possible,
The said motor control apparatus transmits the forced stop information which shows that to the said engine control apparatus, when the forced stop of the said 2nd motor generator by the said stop means is in execution. The vehicle control system according to claim 2 .