JP2009292193A - Controller of hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress deterioration in fuel economy or drivability when a second motor generator is disconnected. <P>SOLUTION: In this controller of a hybrid vehicle, an engine, a first motor generator, and the second motor generator transmit power to rear wheels, and a third motor generator transmits power to front wheels. A power transmission control means changes over between a power transmission mode to transmit power between the second motor generator and a driving axle, and a power transmission release mode to release the power transmission. Specifically, in the power transmission release mode, based on the whole energy efficiency when the third motor generator is in operation, the mode is changed from the power transmission release mode to the power transmission mode. Thereby, the deterioration in the fuel economy or the drivability when the second motor generator is disconnected can be properly suppressed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technical field for controlling a hybrid vehicle having an engine, a first motor generator, and a second motor generator.

  This type of technique is described in Patent Document 1, for example. Patent Document 1 discloses that a hybrid vehicle includes a first motor generator, a second motor generator, and a third motor generator, and the second motor generator and the third motor generator are disconnected from an external load. Technologies that can be configured are proposed. In addition, Patent Document 2 describes a configuration in which an in-wheel motor is applied to a hybrid vehicle, and Patent Document 3 describes a configuration in which a hybrid motor is provided with a second motor generator separation mechanism. ing.

JP 2006-320071 A JP 2007-313982 A JP 2004-282886 A

  However, in the above-described Patent Documents 1 to 3, when an in-wheel motor is applied to a hybrid vehicle having a first motor generator and a second motor generator, the second motor generator can be separated. However, there is no description about appropriately suppressing deterioration of drivability and fuel consumption when the second motor generator is disconnected.

  The present invention has been made to solve the above-described problems, and can appropriately suppress deterioration in drivability and fuel consumption that can occur in a state where the second motor generator is disconnected. An object of the present invention is to provide a control device for a hybrid vehicle.

  In one aspect of the present invention, the control device that controls the hybrid vehicle that travels by transmitting power to each of the front wheels and the rear wheels is one of the front wheels and the rear wheels. An internal combustion engine that transmits power to the wheels, a first motor generator, a second motor generator, and a third wheel that transmits power to the second wheel that is the other of the front wheels and the rear wheels. By separating the motor generator, the power transmission mode for transmitting power between the second motor generator and the drive shaft connected to the first wheel, and the second motor generator and the drive shaft, Power transmission control means for performing control to switch between power transmission cancellation modes for canceling power transmission, and the power transmission control means at the time of setting the power transmission cancellation mode Based on the overall energy efficiency by operating status of the third motor generator, to switch from the power transmission releasing mode to said power transmission mode.

  The hybrid vehicle control device controls a hybrid vehicle having an engine, a first motor generator, a second motor generator, and a third motor generator. In this case, the engine, the first motor generator, and the second motor generator transmit power to the first wheel that is one of the front wheels and the rear wheels, and the third motor generator is the other of the front wheels and the rear wheels. Power is transmitted to the second wheel. The power transmission control means switches between a power transmission mode in which power is transmitted between the second motor generator and the drive shaft, and a power transmission cancellation mode in which power transmission is released by disconnecting the second motor generator. Take control. Specifically, the power transmission control means switches from the power transmission cancellation mode to the power transmission mode based on at least the overall energy efficiency of the operating state of the third motor generator when the power transmission cancellation mode is set. Do. According to the control apparatus for a hybrid vehicle described above, it is possible to reduce loss due to the second motor generator being rotated by appropriately separating the second motor generator. In addition, by appropriately switching from the power transmission release mode to the power transmission mode, it is possible to suppress deterioration in drivability and fuel consumption that may occur when the second motor generator is disconnected. Become.

  In one aspect of the hybrid vehicle control device, the power transmission control unit is configured to perform the overall energy efficiency when the first motor generator is powered and the third motor generator is regenerating. Is switched to the power transmission mode from the power transmission release mode.

  In this aspect, the power transmission control means performs switching from the power transmission cancellation mode to the power transmission mode when so-called power circulation occurs. As a result, it is possible to prevent the drivability from deteriorating due to the braking force applied to the second wheel by the regeneration of the third motor generator.

  Preferably, the control apparatus for a hybrid vehicle further includes first control means for performing control to regenerate the second motor generator after being switched to the power transmission mode by the power transmission control means. In this case, the first control means performs control for adjusting the power balance using the second motor generator instead of using the third motor generator to adjust the power balance.

  In another aspect of the hybrid vehicle control device, the power transmission control means is configured such that when the third motor generator is subjected to rotation limitation due to heat, the overall energy efficiency is not more than a predetermined value. And switching from the power transmission release mode to the power transmission mode.

  According to this aspect, it is possible to suppress the deterioration of drivability caused by the third motor generator being subjected to rotation restriction.

  Preferably, in the above hybrid vehicle control device, when the third motor generator is regeneratively subjected to the rotation restriction, after being switched to the power transmission mode by the power transmission control means. And a second control means for releasing the rotation restriction by controlling the regenerative electric energy of the second motor generator. In this case, the second control means performs control for causing the second motor generator to consume electric power that cannot be consumed by the third motor generator.

  In a preferred embodiment, the third motor generator is constituted by an in-wheel motor. Thereby, a 2nd wheel can be controlled independently on either side.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

[overall structure]
FIG. 1 shows a schematic configuration of a hybrid vehicle 100 to which the present invention is applied. As shown in FIG. 1, a hybrid vehicle 100 mainly includes an engine (internal combustion engine) 1, an ECU (Electronic Control Unit) 4, a power distribution mechanism 5, a first motor generator MG1, and a second motor. Generator MG2, in-wheel motors IWMR, IWML, and wheels 9fR, 9fL, 9rR, 9rL are provided. In the following, when used without distinguishing between left and right, “R” and “L” appended to the end of the reference numerals are omitted. Further, the wheels 9fR and 9fL are collectively described as “front wheel 9f” as appropriate, and the wheels 9rR and 9rL are collectively described as “rear wheel 9r” as appropriate.

  The engine 1 is a heat engine that generates power by burning fuel, and examples thereof include a gasoline engine and a diesel engine. The first motor generator MG1 is connected to the output shaft of the engine 1 via a power distribution mechanism 5 configured to generate a differential action. The first motor generator MG1 generates electric power mainly by receiving the driving force output from the engine 1 and rotates, and a reaction force of torque accompanying the electric power generation acts. In this case, by controlling the rotation speed of first motor generator MG1, the rotation speed of output shaft (drive shaft) 3 of power distribution mechanism 5 changes continuously. A second motor generator MG2 is connected to the output shaft 3 of the power distribution mechanism 5, and the output shaft 3 is connected to the left and right rear wheels 9r via the final reduction gear 8. The rear wheel 9r corresponds to a main drive wheel and corresponds to the first wheel in the present invention. The second motor generator MG2 is electrically connected to the first motor generator MG1 via a battery, an inverter, etc. (not shown) or directly, and mainly generates electric power generated by the power generation of the first motor generator MG1. A driving force is applied to the rear wheel 9r by performing power running using.

  Further, the hybrid vehicle 100 is configured such that in-wheel motors IWMR and IWML are incorporated inside the wheels of the left and right wheels (front wheels) 9fR and 9fL, respectively, so that the left and right front wheels 9f can be driven independently. That is, the hybrid vehicle 100 is a four-wheel drive in which the rear wheel 9r is driven by at least one of the engine 1, the first motor generator MG1, and the second motor generator MG2, and the front wheel 9f is driven by the in-wheel motor IWM. It is configured as a (4WD) car. The in-wheel motor IWM is electrically connected to the first motor generator MG1 via a battery, an inverter, etc. (not shown) or directly, and mainly uses electric power generated by the power generation of the first motor generator MG1. By performing power running, a driving force is applied to the front wheels 9f. The in-wheel motor IWM corresponds to the third motor generator in the present invention. Further, the front wheel 9f corresponds to a sub drive wheel and corresponds to the second wheel in the present invention.

  The ECU 4 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like (not shown). The ECU 4 supplies control signals S1, S2, S3R, S3L, and S4 to the first motor generator MG1, the second motor generator MG2, the in-wheel motors IWMR, IWML, and the engine 1, respectively. Control over. In the present embodiment, the ECU 4 functions as power transmission control means, first control means, and second control means in the present invention. Details of the processing performed by the ECU 4 will be described later.

  FIG. 2 is a diagram more specifically showing the configuration of first motor generator MG1, second motor generator MG2, power distribution mechanism 5 and the like shown in FIG.

  The power distribution mechanism 5 is a planetary gear mechanism that distributes the driving force output from the engine 1 to the first motor generator MG1 and the output shaft 3, and is configured to generate a differential action. Specifically, the power distribution mechanism 5 mainly has a sun gear S1, a carrier C1, and a ring gear R1 as rotating elements. The sun gear S1 is connected to the output shaft of the first motor generator MG1, the carrier C1 is connected to the output shaft of the engine 1, and the ring gear R1 is connected to the output shaft 3. First motor generator MG1 performs a regenerative operation in which the power of engine 1 (power distributed by power distribution mechanism 5) is transmitted via sun gear S1, and electric energy is generated based on this power.

  The output shaft of second motor generator MG2 is connected to reduction mechanism 11. The deceleration mechanism 11 basically has a function of decelerating and outputting the output rotational speed from the second motor generator MG2. Specifically, the speed reduction mechanism 11 mainly has a sun gear S2, a carrier C2, and a ring gear R2 as rotating elements. The sun gear S2 is connected to the output shaft of the second motor generator MG2, the carrier C2 is connected to the output shaft 3, and the ring gear R2 is connected to the clutch mechanism 12.

  In the clutch mechanism 12, one engaging member is physically or mechanically fixed, and the other engaging member is connected to the ring gear R2. When the clutch mechanism 12 is engaged, power transmission is performed between the second motor generator MG2 and the output shaft (drive shaft) 3. This state corresponds to a “power transmission mode”. On the other hand, when clutch mechanism 12 is released, power transmission between second motor generator MG2 and output shaft 3 is released (that is, second motor generator MG2 is disconnected). This state corresponds to the “power transmission release mode”. By configuring the second motor generator MG2 to be disengageable using the clutch mechanism 12 in this manner, the speed reduction mechanism 11 that decelerates the second motor generator MG2 can be increased, and the second speed reduction ratio can be increased. Motor generator MG2 can be configured in a small size.

  The clutch mechanism 12 is switched between engagement / release by an actuator (not shown). Specifically, the ECU 4 switches the engagement / release of the clutch mechanism 12 by controlling the actuator. That is, the ECU 4 performs control to switch between the power transmission mode and the power transmission cancellation mode. For example, the ECU 4 sets the power transmission release mode by releasing the clutch mechanism 12 in a situation where the second motor generator MG2 should be disconnected. In this case, basically, the in-wheel motor IWM generates driving force (that is, powering) by the electric power generated by the regeneration of the first motor generator, and the driving force is applied to the front wheels 9f. Thus, 4WD traveling is realized. Thus, by disconnecting the second motor generator MG2 when it is not necessary, it is possible to reduce a loss due to the second motor generator MG2 being rotated. On the other hand, the ECU 4 sets the power transmission mode by engaging the clutch mechanism 12 in a situation where the second motor generator MG2 should be coupled.

  Here, a setting example of output characteristics in the first motor generator MG1, the second motor generator MG2, and the in-wheel motor IWM will be described.

  As one example, the in-wheel motor IWM is based on the electric power at the vehicle speed at which the second motor generator MG2 is to be disconnected (the vehicle speed is defined based on the allowable rotational speed of the second motor generator MG2). Output settings are made. Specifically, when the second motor generator MG2 is less than the allowable rotational speed, the output of the first motor generator MG1 is the sum of the output of the second motor generator MG2 and the output of the in-wheel motor IWM. When the second motor generator MG2 is equal to or higher than the allowable number of rotations, the first motor generator MG1, the second motor generator MG1, the second motor generator MG2 is less than the output of the in-wheel motor IWM. The output characteristics of the second motor generator MG2 and the in-wheel motor IWM are set.

  In yet another example, the output characteristics of the in-wheel motor IWM are set so that the output of the first motor generator MG1 can be received by the in-wheel motor IWM regardless of the rotational speed of the second motor generator MG2. . Specifically, the output characteristics of the first motor generator MG1 and the in-wheel motor IWM are set so that the output of the first motor generator MG1 is less than the output of the in-wheel motor IWM. In this case, the output characteristic of second motor generator MG2 is freely set.

[Control method]
Next, a method in which the ECU 4 switches between the power transmission mode and the power transmission release mode (a control method performed on the clutch mechanism 12) will be specifically described. Here, conditions for switching between the power transmission mode and the power transmission cancellation mode will be described.

  In the present embodiment, the ECU 4 switches from the power transmission cancellation mode to the power transmission mode based on the overall energy efficiency according to the operating state of the in-wheel motor IWM when the power transmission cancellation mode is set. Specifically, the ECU 4 switches from the power transmission release mode to the power transmission mode when it is determined that deterioration in drivability or fuel consumption may occur in a state where the second motor generator MG2 is disconnected. . In other words, power transmission is canceled when drivability deteriorates due to the control of adjusting the power balance using the in-wheel motor IWM instead of using the second motor generator MG2. Switch from mode to power transmission mode. Note that the ECU 4 prohibits switching to the power transmission release mode when the power transmission mode is already set. As described above, by appropriately switching from the power transmission release mode to the power transmission mode, it is possible to suppress deterioration in drivability and fuel consumption that may occur when the second motor generator MG2 is disconnected. Is possible.

  More specifically, the ECU 4 has the above-described overall energy efficiency when the first motor generator MG1 is powered and the in-wheel motor IWM is regenerating, that is, when so-called power circulation is occurring. The power transmission cancel mode is switched to the power transmission mode when it is determined that the value is equal to or less than the predetermined value. Thereby, it becomes possible to suppress that drivability deteriorates due to the braking force being applied to the front wheels 9f due to regeneration of the in-wheel motor IWM. Furthermore, when the in-wheel motor IWM is subjected to rotation restriction due to heat, the ECU 4 determines that the overall energy efficiency is less than or equal to a predetermined value, and switches from the power transmission release mode to the power transmission mode. As a result, it is possible to suppress deterioration in drivability that occurs when the in-wheel motor IWM is subjected to rotation restriction.

  Here, with reference to FIG. 3, a specific example of a control process performed by the ECU 4 for the clutch mechanism 12 will be described. FIG. 3 is a flowchart showing a control process for the clutch mechanism 12 in the present embodiment. In this process, mainly when power circulation occurs and when the in-wheel motor IWM is restricted by heat, the release of the clutch mechanism 12 is prohibited, thereby suppressing deterioration of drivability. I am trying. Further, by prohibiting the release of the clutch mechanism 12 depending on the power generation situation when there is a request for 4WD travel, fuel consumption and 4WD performance are improved. This process is repeatedly executed by the ECU 4. Further, it is assumed that the clutch mechanism 12 is in an engaged state at the start of the processing.

  First, in step S101, the ECU 4 determines whether or not power circulation has occurred based on a driver request, vehicle speed, or the like. That is, it is determined whether the first motor generator MG1 is powering and the in-wheel motor IWM is regenerating. If power circulation has occurred (step S101; Yes), the process proceeds to step S106. In this case, the ECU 4 prohibits the release of the clutch mechanism 12 in order to prevent the drivability from deteriorating due to the braking force applied to the front wheels 9f due to regeneration of the in-wheel motor IWM. (Step S106). That is, the ECU 4 prohibits switching from the power transmission mode to the power transmission cancellation mode. Furthermore, ECU4 cancels the regeneration state in in-wheel motor IWM by performing control to regenerate second motor generator MG2 instead of in-wheel motor IWM. That is, the ECU 4 performs control so as to match the power balance using the second motor generator MG2 instead of using the in-wheel motor IWM to match the power balance. When the above process ends, the process exits the flow. If the power transmission cancellation mode is set when the process proceeds to step S106, the ECU 4 switches from the power transmission cancellation mode to the power transmission mode.

  Next, when power circulation has not occurred (Step S101; No), processing progresses to Step S102. In step S102, the ECU 4 determines whether or not the current vehicle speed is equal to or lower than the vehicle speed at which engine stop is prohibited (engine stop prohibition vehicle speed). For example, the engine stop prohibition vehicle speed corresponds to a vehicle speed at the time of starting, or a vehicle speed set so that the engine 1 should not be stopped from the viewpoint of drivability. If the second motor generator MG2 is disconnected when the vehicle speed is below the engine stop prohibition vehicle speed, the engine 1 may not start properly or the engine 1 may stop. I can say that. That is, if the second motor generator MG2 is disconnected, it can be said that drivability may deteriorate.

  When the vehicle speed is equal to or lower than the engine stop prohibition vehicle speed (step S102; Yes), the process proceeds to step S106. In this case, the ECU 4 prohibits the release of the clutch mechanism 12 in order to appropriately start the engine 1 or appropriately suppress the engine 1 from stopping (step S106). That is, the ECU 4 prohibits switching from the power transmission mode to the power transmission cancellation mode. When the above process ends, the process exits the flow. If the power transmission cancellation mode is set when the process proceeds to step S106, the ECU 4 switches from the power transmission cancellation mode to the power transmission mode.

  Next, when the vehicle speed is higher than the engine stop prohibition vehicle speed (step S102; No), the process proceeds to step S103. In step S103, the ECU 4 determines whether or not there is a request to travel at 4WD (4WD request). For example, the ECU 4 determines that there is a 4WD request when the front wheel 9f is slipping or when the outside air temperature is equal to or lower than a predetermined temperature. If there is a 4WD request (step S103; Yes), the process proceeds to step S104. If there is no 4WD request (step S103; No), the process proceeds to step S105.

  In step S104, the ECU 4 requires the electric power generated by the first motor generator MG1 (hereinafter also referred to as “MG1 electric power”) to provide a desired driving force from the in-wheel motor IWM. It is determined whether it is less than (required power). If the MG1 power is less than the required power (step S104; Yes), the process proceeds to step S106. In this case, the ECU 4 prohibits the release of the clutch mechanism 12 in order to generate power not only by the first motor generator MG1 but also by the second motor generator MG2 in order to satisfy the necessary power of the in-wheel motor IWM. (Step S106). That is, the ECU 4 prohibits switching from the power transmission mode to the power transmission cancellation mode. Specifically, the ECU 4 regenerates the second motor generator MG2 to supplement the power shortage with respect to the required power with the power generated by the second motor generator MG2. By doing so, it is possible to achieve both 4WD performance and fuel efficiency. When the above process ends, the process exits the flow. If the power transmission cancellation mode is set when the process proceeds to step S106, the ECU 4 switches from the power transmission cancellation mode to the power transmission mode.

  Next, when MG1 electric power is more than required electric power (step S104; No), a process progresses to step S105. In step S105, the ECU 4 determines whether or not the in-wheel motor IWM is subjected to rotation limitation due to heat. That is, it is determined whether or not the in-wheel motor IWM has reached a predetermined temperature or higher and is subject to rotation restriction. When the in-wheel motor IWM is subjected to rotation limitation (step S105; Yes), the process proceeds to step S106. In this case, the ECU 4 prohibits the release of the clutch mechanism 12 in order to prevent the drivability from being deteriorated due to the in-wheel motor IWM being subjected to rotation restriction (step S106). That is, the ECU 4 prohibits switching from the power transmission mode to the power transmission cancellation mode. Specifically, the ECU 4 performs control for causing the second motor generator MG2 to consume electric power that cannot be consumed by the in-wheel motor IWM. In other words, by using the second motor generator MG2, control for adjusting the power balance is performed. For example, if the ECU 4 receives a rotation restriction while the in-wheel motor IWM is regenerating, the ECU 4 releases the rotation restriction of the in-wheel motor IWM by controlling the regenerative power amount of the second motor generator MG2. To do. When the above process ends, the process exits the flow. If the power transmission cancellation mode is set when the process proceeds to step S106, the ECU 4 switches from the power transmission cancellation mode to the power transmission mode.

  On the other hand, when the in-wheel motor IWM is not subjected to rotation restriction (step S105; No), the process exits the flow without performing the process of step S106. In such a case, it can be said that it is not necessary to couple the second motor generator MG2. That is, it can be said that the second motor generator MG2 may be separated. Therefore, the ECU 4 permits the release of the clutch mechanism 12. By doing so, it is possible to reduce a loss caused by the second motor generator MG2 being rotated.

  According to the processing described above, by prohibiting the release of the clutch mechanism 12, it is possible to appropriately suppress the deterioration of drivability and the deterioration of fuel consumption that may occur in a state where the second motor generator MG2 is disconnected. Become. Moreover, it becomes possible to make 4WD performance and fuel consumption balance appropriately.

  In the above, an example in which the in-wheel motor IWM is used as the third motor generator has been described. However, the use of such a motor is not limited.

The schematic structure of the hybrid vehicle by this embodiment is shown. The structure of a motor generator, a power transmission mechanism, etc. is shown. It is a flowchart which shows the control processing with respect to the clutch mechanism in this embodiment.

Explanation of symbols

1 Engine 3 Output shaft 4 ECU
5 Power distribution mechanism 9f Front wheel 9r Rear wheel 11 Reduction mechanism 12 Clutch mechanism MG1 First motor generator MG2 Second motor generator IWM In-wheel motor

Claims (6)

A control device that controls a hybrid vehicle that travels by transmitting power to each of a front wheel and a rear wheel,
An internal combustion engine that transmits power to a first wheel that is one of the front wheel and the rear wheel, a first motor generator, and a second motor generator;
A third motor generator that transmits power to a second wheel that is the other of the front wheels and the rear wheels;
The power transmission mode in which power is transmitted between the second motor generator and the drive shaft connected to the first wheel, and the power transmission is canceled by separating the second motor generator and the drive shaft. Power transmission control means for performing control to switch between power transmission cancellation modes to perform,
The power transmission control means switches from the power transmission cancellation mode to the power transmission mode based on the overall energy efficiency of the operating state of the third motor generator when the power transmission cancellation mode is set. A control apparatus for a hybrid vehicle characterized by the above.   The power transmission control means determines that the overall energy efficiency is less than or equal to a predetermined value when the first motor generator is powered and the third motor generator is regenerating, The hybrid vehicle control device according to claim 1, wherein switching from the power transmission release mode to the power transmission mode is performed.   The control apparatus for a hybrid vehicle according to claim 2, further comprising first control means for performing control to regenerate the second motor generator after being switched to the power transmission mode by the power transmission control means.   The power transmission control means determines that the overall energy efficiency is less than or equal to a predetermined value when the third motor generator is subjected to rotation limitation due to heat, and performs the power transmission from the power transmission release mode. The control apparatus of the hybrid vehicle as described in any one of Claims 1 thru | or 3 which switches to a mode.   When the rotation limitation is imposed when the third motor generator is regenerating, after the power transmission control means switches to the power transmission mode, the regenerative electric energy of the second motor generator is changed. The hybrid vehicle control device according to claim 4, further comprising second control means for releasing the rotation restriction by controlling.   The control device for a hybrid vehicle according to any one of claims 1 to 5, wherein the third motor generator is configured by an in-wheel motor.

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