JP5303953B2 - Control device for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller for a hybrid vehicle capable of securing travel performance responding at a high level, in either case of laying stress on a mileage or of laying stress on drivability. <P>SOLUTION: This controller for the hybrid vehicle includes a control means such as an ECU. The control means changes a speed change ratio mode over in response to a position of a current driving operation point, on a map set with a continuously variable speed change ratio mode area and a fixed speed change ratio mode area, and defined by a target driving force and a vehicular speed. An overlapping area is set between the continuously variable speed change ratio mode area and the fixed speed change ratio mode area, to prohibit the change-over of the speed change ratio mode. The control means widens the overlapping area, when laying stress on the drivability, compared with that when laying stress on the mileage. The travel performance responding at the high level is secured by this manner, in either case of laying stress on the mileage or of laying stress on the drivability. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a control device suitable for a hybrid vehicle.

  A hybrid vehicle including a power source such as an electric motor or a motor generator in addition to an internal combustion engine (engine) is known. In a hybrid vehicle, an internal combustion engine is operated in a highly efficient state as much as possible, while excess or deficiency of driving force or engine brake is compensated by an electric motor or a motor generator.

  As an example of such a hybrid vehicle, there is a hybrid vehicle configured to be able to operate by switching between a continuously variable gear ratio mode and a fixed gear ratio mode. This hybrid vehicle has a power distribution mechanism in which two planetary gear mechanisms are combined, and the power distribution mechanism is connected to the engine, the first motor generator, the output shaft, and the brake. In a state where the brake is released, the engine speed is continuously changed by continuously changing the rotation speed of the first motor generator, and the operation in the continuously variable transmission ratio mode is executed. On the other hand, in a state where the brake is fixed, the gear ratio is fixed by preventing one rotation of the rotating element, and the operation in the fixed gear ratio mode is executed.

  For example, in Patent Document 1 below, when the vehicle is traveling in one of the continuously variable gear ratio mode and the fixed gear ratio mode, the driving point of the vehicle exists in an overlap region where both modes can be selected. In this case, a technique for prohibiting the change to the other gear ratio mode is described. Patent Document 2 discloses a technique in which when a transition from a predetermined travel mode to another travel mode is detected, the travel mode before the transition is retained for a predetermined time, and the predetermined time is set based on the mode transition time. Have been described. In Patent Document 3, a predetermined width in the required driving force axis direction is set at the boundary between the continuously variable gear ratio mode region and the fixed gear ratio mode region, and a change in the target rotational speed of the rotating element accompanying the mode transition is continuously set. A technique for providing a transition region is described.

JP 2005-16559 A JP 2006-25483 A JP 2005-163912 A

  However, in the technique described in Patent Document 1, since the overlap region is determined in advance, it is difficult to ensure the traveling performance in both cases of emphasis on fuel efficiency and drivability. Patent Document 2 or 3 does not discuss this point at all.

  The present invention has been made to solve the above-described problems, and is a hybrid capable of ensuring a high level of driving performance that meets high levels of fuel efficiency and drivability. It is an object to provide a control device for a vehicle.

One aspect of the present invention is applied to a hybrid vehicle that has an engine and a motor generator as drive sources and is configured to be able to switch the gear ratio mode between a continuously variable gear ratio mode and a fixed gear ratio mode. , Control for switching the gear ratio mode according to the position of the current driving operation point on the map defined by the target driving force and the vehicle speed, in which the continuously variable gear ratio mode region and the fixed gear ratio mode region are set A control device for a hybrid vehicle comprising means, wherein an overlap region that prohibits switching of the gear ratio mode is set between the continuously variable gear ratio mode region and the fixed gear ratio mode region. when the operating state of the engine is lean burn, as compared to the operating state of the engine is not lean burn, the over wrapper To increase the area.

The above hybrid vehicle control device is applied to a hybrid vehicle having an engine and a motor generator as a drive source and capable of switching the gear ratio mode between a continuously variable gear ratio mode and a fixed gear ratio mode. Control device. The hybrid vehicle control device includes control means such as an ECU (Electronic Control Unit). The control means has a gear ratio according to the position of the current driving operation point on the map defined by the target driving force and the vehicle speed in which the continuously variable gear ratio mode region and the fixed gear ratio mode region are set. Switch modes. The continuously variable transmission ratio mode region is an operation region of the continuously variable transmission ratio mode. The fixed gear ratio mode region is an operation region of the fixed gear ratio mode. Between the continuously variable gear ratio mode region and the fixed gear ratio mode region, an overlap region for prohibiting switching of the gear ratio mode is set. The overlap region is defined by the target driving force and the vehicle speed, or by time. Control means when the engine is in the lean burn, as compared to the operating state of the engine is not a lean burn, increasing the overlap region. By doing in this way, it is possible to ensure a driving performance that meets a high level regardless of whether fuel efficiency is important or drivability is important.

  In another aspect of the control apparatus for a hybrid vehicle, the control means is configured to change the current driving operation point from the fixed gear ratio mode region to the continuously variable gear ratio mode region in a direction in which the target driving force increases. When the shift is made, the overlap area is reduced. In this way, it is possible to immediately obtain the driving force required by the driver.

  Applied to a hybrid vehicle having an engine and a motor generator as a drive source and configured to be able to switch between two continuously variable gear ratio modes and a fixed gear ratio mode. A control apparatus for a hybrid vehicle comprising control means for switching a gear ratio mode according to the position of the current driving operation point on a map defined by a target driving force and a vehicle speed, in which a fixed gear ratio mode region is set And, between the continuously variable gear ratio mode region and the fixed gear ratio mode region, an overlap region that prohibits switching of the gear ratio mode is set, and when the control means emphasizes drivability, The overlap region is increased compared to the case where fuel consumption is emphasized. By doing in this way, it is possible to ensure a driving performance that meets a high level regardless of whether fuel efficiency is important or drivability is important.

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

[Configuration of hybrid vehicle]
FIG. 1 shows a schematic configuration of a hybrid vehicle control device according to each embodiment. The example of FIG. 1 is a hybrid vehicle called a mechanical distribution type two-motor type, and includes an engine 1, a first motor generator MG 1, a second motor generator MG 2, and a power distribution mechanism 20. An engine 1 corresponding to a power source and a first motor generator MG1 corresponding to a rotation speed control mechanism are connected to a power distribution mechanism 20. A second motor generator MG2 that is an auxiliary power source for assisting driving torque or braking force is connected to the output shaft 3 of the power distribution mechanism 20 via the MG2 transmission unit 6. Further, the output shaft 3 is connected to the left and right drive wheels 9 via a final reduction gear 8. The first motor generator MG1 and the second motor generator MG2 are electrically connected via a battery, an inverter, or an appropriate controller (not shown) or directly, and the first motor generator MG1 The second motor generator MG2 is driven by the generated electric power. Further, the first motor generator MG1 can be driven by the electric power generated by the second motor generator MG2.

  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 generates power mainly by receiving torque from the engine 1 and rotating, and reaction force torque accompanying power generation acts. By controlling the rotational speed of first motor generator MG1, the rotational speed of engine 1 changes continuously. Such a gear ratio mode is called a continuously variable gear ratio mode. The continuously variable transmission ratio mode is realized by a differential action of a power distribution mechanism 20 described later.

  The second motor generator MG2 is a device that assists the driving torque or the braking force. When assisting the drive torque, the second motor generator MG2 receives power supply and functions as an electric motor. On the other hand, when assisting the braking force, the second motor generator MG2 functions as a generator that is rotated by the torque transmitted from the drive wheels 9 to generate electric power.

  FIG. 2 shows a configuration of first and second motor generators MG1 and MG2 and power distribution mechanism 20 shown in FIG. In FIG. 2, the solid line indicates that they are connected, and the wavy arrow indicates the signal flow.

  The power distribution mechanism 20 is a mechanism that distributes the output torque of the engine 1 to the first motor generator MG1 and the output shaft 3, and is configured to generate a differential action. Specifically, the engine 1 is connected to the first rotating element among the four rotating elements that are provided with a plurality of sets of differential mechanisms and have a differential action, and the first motor generator MG1 is connected to the second rotating element. Are connected, the output shaft 3 is connected to the third rotating element, and the dog clutch 5 is connected to the fourth rotating element. Further, not only the dog clutch 5 but also a wet clutch or the like may be used. In a state where dog clutch 5 is released, the rotation speed of engine 1 is continuously changed by continuously changing the rotation speed of first motor generator MG1, and the continuously variable transmission ratio mode is realized. On the other hand, when the dog clutch 5 is engaged and the fourth rotating element is fixed, the gear ratio determined by the power distribution mechanism 20 is fixed to the overdrive state (that is, the engine speed is smaller than the output speed). The fixed gear ratio mode is realized. The connection and release of the dog clutch 5 are controlled based on a control signal from the ECU 50.

  The power distribution mechanism 20 is configured by combining two planetary gear mechanisms. The first planetary gear mechanism includes a ring gear 21, a carrier 22, and a sun gear 23, and the second planetary gear mechanism includes a ring gear 25, a carrier 26, and a sun gear 27.

  The output shaft 2 of the engine 1 is connected to the carrier 22 of the first planetary gear mechanism, and the carrier 22 is connected to the ring gear 25 of the second planetary gear mechanism. These constitute the first rotating element. The rotor 11 of the first motor generator MG1 is connected to the sun gear 23 of the first planetary gear mechanism, and these constitute a second rotating element.

  The ring gear 21 of the first planetary gear mechanism and the carrier 26 of the second planetary gear mechanism are connected to each other and to the output shaft 3. These constitute the third rotating element. The sun gear 27 of the second planetary gear mechanism corresponds to the fourth rotating element and is connected to the brake unit 7 via the dog clutch 5.

  An ECU (Electronic Control Unit) 50 includes a CPU, ROM, RAM, A / D converter, input / output interface, and the like (not shown). Based on detection signals from various sensors, the engine 1 and the first motor generator MG1 Then, drive control of the second motor generator MG2 and the dog clutch 5 is performed. Specifically, the ECU 50 determines the optimum gear ratio mode based on the vehicle speed and the target driving force, controls the dog clutch 5, and sets the current gear ratio mode to the optimum gear ratio mode.

[First Embodiment]
Next, a hybrid vehicle control method according to the first embodiment of the present invention will be described with reference to FIG. FIG. 3 is a map showing a driving region defined by the target driving force and the vehicle speed. In FIG. 3, the horizontal axis indicates the vehicle speed, and the vertical axis indicates the target driving force. In addition, the continuously variable transmission ratio mode operation region (outside the boundary Area 2) is indicated as “continuously variable transmission ratio mode region”, and the fixed transmission ratio mode operation region (inside the boundary Area 1) is defined as “fixed transmission ratio mode region”. Show.

  The ECU 50 determines the gear ratio mode depending on where the point (driving operation point) determined by the target driving force and the vehicle speed is on the map shown in FIG. Specifically, the ECU 50 obtains the driving operation point based on the vehicle speed obtained by the vehicle speed sensor or the like, and the target driving force obtained by the accelerator sensor or the like. When it is determined that the driving operation point is in the continuously variable transmission ratio mode region on the map, the ECU 50 sets the transmission ratio mode to the continuously variable transmission ratio mode and determines that the driving operation point is in the fixed transmission ratio mode region. In this case, the gear ratio mode is set to the fixed gear ratio mode. On the map shown in FIG. 3, the continuously variable gear ratio mode region and the fixed gear ratio mode region are arranged in regions where the fuel efficiency is the best according to the driving operation point. Therefore, by determining the gear ratio mode according to where the driving operation point is on the map, it is possible to travel in the most efficient gear ratio mode according to the driving operation point, and to ensure fuel consumption performance Can do.

  As shown in FIG. 3, the fixed gear ratio mode region is not provided in a low vehicle speed region or a region where the target driving force is relatively large. This is because, in the low vehicle speed range, if the fixed gear ratio mode is set, the engine 1 will vibrate and a humming noise. In the region where the target driving force is relatively large, if the fixed gear ratio mode is set, This is because the gear ratio becomes high, making it difficult to produce a driving force.

  An overlap region is provided between the continuously variable gear ratio mode region and the fixed gear ratio mode region (the region between the boundary Area1 and the boundary Area2 in FIG. 3). Specifically, in the first embodiment, the overlap region is provided as a region defined by the vehicle speed and the target driving force, as shown in the map of FIG. In the overlap region, switching of the gear ratio mode is prohibited.

  Therefore, in the hybrid vehicle control method according to the first embodiment, the ECU 50 determines the fixed gear ratio mode region, the continuously variable gear ratio mode region, the overlap based on the driving operation point defined by the target driving force and the vehicle speed. It is determined which of the areas is within the area, and the gear ratio mode is determined. An example will be specifically described below.

  First, on the map shown in FIG. 3, when the driving operation point moves from the point D1 to the point Sb1 via the point Sa1, that is, from the continuously variable speed ratio mode area to the fixed speed ratio mode via the overlap area. The case of moving to an area will be described. When the driving operation point departs from the point D1 and reaches the point Sa1, that is, when it reaches the overlap region from the continuously variable gear ratio mode region, switching of the gear ratio mode is prohibited in the overlap region. The speed ratio mode immediately before reaching the overlap region, that is, the continuously variable speed ratio mode is maintained. When the driving operation point reaches the point Sb1 from the point Sa1, that is, when the driving operation point reaches the fixed gear ratio mode region from the overlap region, the gear ratio mode is changed from the continuously variable gear ratio mode to the fixed gear ratio mode. Is switched to. That is, when the driving operation point reaches the overlap region from the continuously variable gear ratio mode region, the ECU 50 does not switch the gear ratio mode to the fixed gear ratio mode and remains in the continuously variable gear ratio mode. When the vehicle reaches the fixed gear ratio mode region, the gear ratio mode is switched from the continuously variable gear ratio mode to the fixed gear ratio mode.

  Next, when the operating point moves from the point D2 to the point Sa2 via the point Sb2, that is, from the fixed gear ratio mode region to the continuously variable gear ratio mode region via the overlap region. State. When the driving operation point reaches the point Sb2 from the point D2, that is, when it reaches the overlap region from the fixed gear ratio mode region, switching of the gear ratio mode is prohibited in the overlap region. The speed ratio mode immediately before reaching, that is, the fixed speed ratio mode is maintained. When the driving operation point reaches from the point Sb2 to the point Sa2, that is, when the driving operation point reaches from the overlap region to the continuously variable transmission ratio mode region, the transmission ratio mode changes from the fixed transmission ratio mode to the continuously variable transmission ratio mode. Switch to mode. That is, when the operating point reaches the overlap region from the fixed gear ratio mode region, the ECU 50 does not switch the gear ratio mode to the continuously variable gear ratio mode but remains in the fixed gear ratio mode. When reaching the continuously variable gear ratio mode region, the gear ratio mode is switched from the fixed gear ratio mode to the continuously variable gear ratio mode.

  Next, in consideration of the characteristics of the overlap region described above, a case will be described in which the operating point moves along the routes L1 and L2 near the overlap region. When the driving operation point moves along the path L1, it passes through the points A1, A2, and A3 on the boundary between the fixed gear ratio mode area and the overlap area, and when it moves along the path L2, It passes through point B1, point B2, and point B3 on the boundary between the step speed ratio mode region and the overlap region.

  If the overlap area is not set, for example, if the area inside the boundary Area1 is the fixed gear ratio mode area and the area outside the boundary Area1 is the continuously variable speed ratio mode area, the driving operation point is the route When moving along L1, the gear ratio mode is switched every time it passes through points A1, A2, and A3. On the other hand, when the area inside the boundary Area 2 is the fixed speed ratio mode area and the area outside the boundary Area 2 is the continuously variable speed ratio mode area, when the driving operation point moves along the path L2, the points B1 and B2 Every time the point B3 is passed, the gear ratio mode is switched. That is, if either one of the area surrounded by the boundary Area1 or the area surrounded by the area Area2 is set as the fixed gear ratio mode region, the gear ratio mode may be frequently switched, and the clutch There is a possibility that drivability will be reduced due to shocks caused by the coupling / release, motor generator noise caused by fluctuations in engine speed, and shocks caused by fluctuations in driving torque transmitted to the output shaft.

  On the other hand, when the overlap region is set, the gear ratio mode is switched regardless of whether the driving operation point moves along the route L1 or moves along the route L2. I can't.

  For example, in the case where the driving operation point moves along the path L1, when the driving operation point reaches the point A1 from the start point, that is, when the driving operation point reaches the overlap region from the fixed gear ratio mode, in the overlap region, Since the gear ratio mode immediately before reaching is held, the fixed gear ratio mode is held as the gear ratio mode. When the driving operation point reaches the point A2 from the point A1, the fixed speed ratio mode is maintained as the speed ratio mode because the fixed speed ratio mode region is reached again. When the driving operation point reaches the point A3 from the point A2, the speed ratio mode immediately before reaching is maintained by reaching the overlap region, so that the fixed speed ratio mode is maintained as the speed ratio mode. That is, the speed ratio mode is maintained in the fixed speed ratio mode over the entire path L1.

  Further, the case where the driving operation point moves along the route L2 will be described. When the driving operation point reaches the point B1 from the start point, that is, when the driving operation point reaches the overlap region from the continuously variable transmission ratio mode region, the overlap is performed. Since the speed ratio mode immediately before reaching the region is maintained, the continuously variable speed ratio mode is maintained as the speed ratio mode. When the driving operation point reaches the point B2 from the point B1, the driving operation point reaches the continuously variable transmission ratio mode region again, so that the continuously variable transmission ratio mode is maintained as the transmission ratio mode. When the driving operation point reaches the point B3 from the point B2, the speed ratio mode immediately before reaching is maintained by reaching the overlap region, so the continuously variable speed ratio mode is maintained as the speed ratio mode. That is, the speed ratio mode is maintained in the continuously variable speed ratio mode over the entire path L2.

  As can be seen from the above description, by setting the overlap region, it is possible to prevent the gear ratio mode from being frequently switched, and to suppress a decrease in drivability.

  Here, the size of the overlap region differs depending on whether the fuel efficiency is important or the drivability is important. The size of the overlap region in the case of emphasizing drivability is set larger than the size of the overlap region in the case of emphasis on fuel efficiency. This is because when the drivability is important, it is preferable that the gear ratio mode is not switched as much as possible. Therefore, it is preferable to switch the transmission mode frequently in accordance with the continuously variable transmission ratio mode region and the fixed transmission ratio mode region that are arranged in the region where the fuel efficiency is the best, so a relatively small overlap region is set. Because.

  However, in either case, since the size of the overlap region is determined in advance, the size that is biased to either the case where importance is attached to fuel efficiency or the case where importance is attached to drivability In other words, it is difficult to ensure both high fuel efficiency and drivability at a high level at the same time.

  Therefore, in the hybrid vehicle control method according to the first embodiment, the ECU 50 further switches the size of the overlap region in accordance with, for example, a request from the driver or the operating state of the engine 1. In other words, the ECU 50 increases the overlap region when drivability is emphasized as compared to when fuel efficiency is emphasized.

  As an example of switching the size of the overlap region in response to a request from the driver, for example, it is conceivable to provide a “fuel consumption priority switch” near the driver's seat that supplies a detection signal to the ECU 50. For example, when the driver wants to place importance on fuel efficiency, the driver makes an importance request on the fuel efficiency performance to the ECU 50 by pressing a “fuel consumption priority switch”. When the ECU 50 determines that the “fuel consumption priority switch” is pressed based on the detection signal from the “fuel consumption priority switch”, the ECU 50 sets the size of the overlap area to the size when the fuel efficiency priority is set. When it is determined that the “fuel consumption emphasis switch” is released, the size of the overlap area is set to the size when the drivability is emphasized.

  As an example of switching the size of the overlap region according to the operating state of the engine 1, for example, the ECU 50 operates the engine 1 based on detection signals from various sensors such as an air-fuel ratio (A / F) sensor. It may be determined whether the state is lean burn. When the ECU 50 determines that the operating state of the engine 1 is lean burn, the ECU 50 sets the size of the overlap region to the size when fuel economy is emphasized, and when it is not lean burn, for example, stoichiometric If it is determined, the size of the overlap area is set to the size when emphasizing drivability.

  Next, an example of switching the size of the overlap area will be described with reference to FIG. FIG. 4 is a map showing operating regions for each of the continuously variable transmission ratio mode and the fixed transmission ratio mode. In the map shown in FIG. 4, a region OveA indicates an overlap region when drivability is important, and a region OveB indicates an overlap region when fuel efficiency is important.

  The ECU 50 sets the area OverA as the overlap area when the size of the overlap area is set to the size when the drivability is emphasized based on the request from the driver and the operating state of the engine 1. Therefore, when the driving operation point moves from the continuously variable speed ratio mode area to the fixed speed ratio mode area via the overlap area OveA, starting from the point D1, as indicated by the solid arrow, the ECU 50 When the driving operation point reaches the region OveA, the gear ratio mode is maintained in the continuously variable gear ratio mode. The ECU 50 switches the gear ratio mode from the continuously variable gear ratio mode to the fixed gear ratio mode when the driving operation point reaches the point S3b1, that is, when the driving point reaches the fixed ratio gear ratio mode region.

  When the driving operation point moves from the fixed gear ratio mode region to the continuously variable gear ratio mode region via the overlap region OveA, starting from the point D2, as indicated by the solid line arrow, the ECU 50 When the point reaches the area OveA, the gear ratio mode is held in the fixed gear ratio mode. The ECU 50 switches the gear ratio mode from the fixed gear ratio mode to the continuously variable gear ratio mode when the driving operation point reaches the point S4.

  On the other hand, the ECU 50 sets the area OveB as the overlap area when the size of the overlap area is set to the size when the fuel efficiency is emphasized based on the request from the driver or the operating state of the engine 1. Therefore, when the driving operation point moves from the continuously variable speed ratio mode area to the fixed speed ratio mode area via the overlap area OveB, starting from the point D1 as indicated by the broken line arrow, the ECU 50 When the driving operation point reaches the region OveB, the gear ratio mode is held in the fixed gear ratio mode. The ECU 50 switches the gear ratio mode from the continuously variable gear ratio mode to the fixed gear ratio mode when the driving operation point reaches the point S3b2, that is, when the driving point reaches the fixed ratio gear ratio mode region.

  When the driving operation point moves from the fixed gear ratio mode region to the continuously variable gear ratio mode region via the overlap region OveB, starting from the point D2, as shown by a broken line arrow, the ECU 50 When the point reaches the region OveB, the gear ratio mode is held in the fixed gear ratio mode. The ECU 50 switches the gear ratio mode from the fixed gear ratio mode to the continuously variable gear ratio mode when the driving operation point reaches the point S4.

  As described above, it is assumed that the size of the overlap region is switched between the case of emphasizing fuel efficiency and the case of drivability. By increasing the size, it is possible to ensure a high level of driving performance in both cases of emphasis on fuel efficiency and drivability.

  In the fixed gear ratio mode, as described above, the gear ratio determined by the power distribution mechanism 20 is fixed to the overdrive state (that is, the engine speed is smaller than the output speed). Become. Therefore, in a state where the vehicle is traveling in the fixed gear ratio mode, for example, when the driver depresses the accelerator, the target driving force is increased and the fixed gear ratio mode is switched to the continuously variable gear ratio mode ( In the case of FIG. 4, when the operating point moves from the point D3 to the point Sc1, it is better to make the overlap region as small as possible. This is because the fixed gear ratio mode is maintained in the overlap region in this case. That is, in order to increase the driving force smoothly, it is better to immediately switch to the continuously variable transmission ratio mode than to maintain the fixed transmission ratio mode where it is difficult to output the driving force.

  Therefore, when the operating point moves from the point D3 to the point Sc1, that is, when the target driving force increases, the ECU 50 shifts from the fixed gear ratio mode region to the continuously variable gear ratio mode region. The overlap region at this time is set to 0, or as shown in FIG. 4, it is made smaller than the overlap region in other cases. In this way, it is possible to immediately obtain the driving force required by the driver.

  According to the control method of the first embodiment described above, the size of the overlap region is switched between the case of emphasizing fuel efficiency and the case of drivability. In comparison, by making the overlap region large, it is possible to ensure a high level of driving performance in both cases of emphasis on fuel efficiency and drivability.

[Second Embodiment]
Next, a hybrid vehicle control method according to a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a map showing an operation region according to the second embodiment. In FIG. 5, a boundary Bline indicates a boundary between the continuously variable gear ratio mode region and the fixed gear ratio mode region. In the hybrid vehicle control method according to the first embodiment described above, the overlap region is set on the map defined by the vehicle speed and the target driving force. On the other hand, in the hybrid vehicle control method according to the second embodiment, the overlap region is defined by time instead of by vehicle speed and target driving force. In other words, that is, in the overlap region, change of the gear ratio mode is prohibited for a predetermined time (hereinafter referred to as “set time”). That is, the gear ratio mode immediately before reaching the overlap region is maintained for the set time. The details will be described below.

  First, the case where the driving operation point moves from the point C1 to the point C3 on the map shown in FIG. 5 will be described. When the driving operation point reaches the point C2 starting from the point C1, that is, when it reaches the fixed gear ratio mode region from the continuously variable gear ratio mode region, the gear ratio mode is not switched to the fixed ratio gear ratio mode. In addition, the continuously variable transmission ratio mode is maintained for the set time. The gear ratio mode is switched from the continuously variable gear ratio mode to the fixed gear ratio mode after a set time has elapsed since reaching the fixed gear ratio mode region. Accordingly, if the driving operation point moves from the point C2 to the point C3 during the set time, the region Ove1 from the point C2 to the point C3 is the overlap region in this case. That is, the boundary Bline is a boundary between the continuously variable transmission ratio mode region and the fixed transmission ratio mode region and also a boundary between the continuously variable transmission ratio mode region and the overlap region Ove1.

  Next, a case where the driving operation point moves from the point C3 to the point C1 will be described. When the driving operation point reaches the point C2 starting from the point C3, that is, when the driving operation point reaches the continuously variable transmission ratio mode from the fixed transmission ratio mode region, the transmission ratio mode is not switched to the continuously variable transmission ratio mode. In addition, the fixed gear ratio mode is maintained for the set time. The gear ratio mode is switched from the fixed gear ratio mode to the continuously variable gear ratio mode after a set time has elapsed since reaching the continuously variable gear ratio mode region. Accordingly, if the driving operation point moves from the point C2 to the point C1 during the set time, the region Ove2 from the point C2 to the point C1 becomes the overlap region in this case. That is, the boundary Bline is a boundary between the continuously variable gear ratio mode region and the fixed gear ratio mode region, and is also a boundary between the fixed gear ratio mode region and the overlap region Ove2.

  As described above, even when the overlap region is defined by time, it is possible to prevent the gear ratio mode from being frequently switched, and it is possible to suppress a decrease in drivability.

  Next, the hybrid vehicle control process according to the second embodiment will be described with reference to the flowchart shown in FIG. The flowchart shown in FIG. 6 shows a control process in each of switching from the continuously variable gear ratio mode to the fixed gear ratio mode or switching from the fixed gear ratio mode to the continuously variable gear ratio mode.

  In step S101, the ECU 50 obtains the current driving operation point based on the vehicle speed obtained from the vehicle speed sensor or the like and the target driving force obtained from the accelerator sensor or the like. A speed ratio mode (required speed ratio mode) determined on the map shown is obtained. When the ECU 50 determines that the required speed ratio mode is the fixed speed ratio mode (step S101: Yes), the ECU 50 proceeds to the processing of step S102, and the required speed ratio mode is not the fixed speed ratio mode, that is, the continuously variable speed change mode. If it is determined that the mode is the ratio mode (step S101: No), the process proceeds to step S106.

  The processing from step S102 to step S105 described below shows control processing at the time of switching from the continuously variable gear ratio mode to the fixed gear ratio mode.

  In step S102, the ECU 50 determines whether or not the current gear ratio mode is the continuously variable gear ratio mode. If the ECU 50 determines that the current gear ratio mode is the continuously variable gear ratio mode (step S102: Yes), the ECU 50 proceeds to step S103. Proceed to processing. On the other hand, when it is determined that the current gear ratio mode is not the continuously variable gear ratio mode, that is, the fixed gear ratio mode (step S102: No), the ECU 50 returns this control process. That is, the case where the process proceeds to step S103 is a case where the current speed ratio mode is the continuously variable speed ratio mode and the required speed ratio mode is the fixed speed ratio mode. The map shown in FIG. 5 shows, for example, when the driving operation point has reached the point C2 starting from the point C1.

  In step S103, the ECU 50 obtains an elapsed time after the required gear ratio mode becomes the continuously variable gear ratio mode based on, for example, a detection signal from a timer, and determines whether or not the elapsed time exceeds the set time. judge. When it is determined that the elapsed time does not exceed the set time (step S103: No), the ECU 50 returns this control process. That is, the case where the elapsed time does not exceed the set time is a case where the operation point is located in the overlap region Ove1 in the map shown in FIG. At this time (when it is determined that the elapsed time does not exceed the set time), the ECU 50 starts the timer when it is determined that the timer is not started, that is, the elapsed time is zero. Let On the other hand, if the ECU 50 determines in step S103 that the elapsed time exceeds the set time (step S103: Yes), the process proceeds to step S104. The case where the elapsed time exceeds the set time indicates, for example, when the driving operation point has reached the point C3 from the point C2 in the map shown in FIG.

  In step S104, the ECU 50 resets the timer and sets the elapsed time to zero. In step S105, the ECU 50 switches the current gear ratio mode from the continuously variable gear ratio mode to the fixed gear ratio mode. Thereafter, the ECU 50 returns this control process.

  The processing from step S106 to step S109 described below shows control processing when switching from the fixed gear ratio mode to the continuously variable gear ratio mode.

  In step S101, if the ECU 50 determines that the requested gear ratio mode is the continuously variable gear ratio mode (step S101: No), the process proceeds to step S106, and the ECU 50 determines that the current gear ratio mode is a fixed gear ratio mode. It is determined whether or not the mode is the ratio mode. If the ECU 50 determines that the current gear ratio mode is the fixed gear ratio mode (step S106: Yes), the ECU 50 proceeds to the process of step S107. On the other hand, when the ECU 50 determines that the current gear ratio mode is not the fixed gear ratio mode, that is, the continuously variable gear ratio mode (step S106: No), the ECU 50 returns this control process. That is, the case of proceeding to the processing of step S107 is a case where the current speed ratio mode is the fixed speed ratio mode and the required speed ratio mode is the continuously variable speed ratio mode. The map shown in FIG. 5 shows, for example, when the driving operation point reaches the point C2 starting from the point C3.

  In step S107, the ECU 50 obtains an elapsed time after the required gear ratio mode becomes the fixed gear ratio mode, for example, based on a detection signal from a timer, and determines whether the elapsed time exceeds the set time. To do. When the ECU 50 determines that the elapsed time does not exceed the set time (step S107: No), the ECU 50 returns this control process. That is, the case where the elapsed time does not exceed the set time is, for example, a case where the driving operation point is located in the overlap region Over2 in the map shown in FIG. At this time (when it is determined that the elapsed time does not exceed the set time), the ECU 50 starts the timer when it is determined that the timer is not started, that is, the elapsed time is zero. Let On the other hand, if the ECU 50 determines in step S107 that the elapsed time exceeds the set time (step S107: Yes), the process proceeds to step S108. The case where the elapsed time exceeds the set time indicates, for example, when the driving operation point has reached the point C1 from the point C2 in the map shown in FIG.

  In step S108, the ECU 50 resets the timer and sets the elapsed time to zero. In step S109, the ECU 50 switches the current gear ratio mode from the fixed gear ratio mode to the continuously variable gear ratio mode. Thereafter, the ECU 50 returns this control process.

  As described above, even when the overlap region is defined by time, it is possible to prevent the gear ratio mode from being frequently switched, and to suppress a decrease in drivability.

  Here, the size of the overlap region can be changed by changing the set time during which the gear ratio mode is maintained. For example, if the setting time in the above example is the setting time when emphasizing drivability, the setting time when emphasizing fuel efficiency is set shorter than the setting time when emphasizing drivability. As a result, as shown in FIG. 5, the overlap areas Ove3 and Ove4 when the fuel efficiency is emphasized are set smaller than the overlap areas Ove1 and Ove2 when the drivability is emphasized.

  Also in the second embodiment, as in the first embodiment, the ECU 50 can switch the size of the overlap region based on a request from the driver or the operating state of the engine 1. For example, if the ECU 50 sets the size of the overlap area to the size when emphasizing drivability based on the request from the driver or the operating state of the engine 1, the set time is set to emphasize drivability. By setting the set time in the case, the areas Ove1 and Ove2 are set as overlap areas. On the other hand, if the ECU 50 sets the size of the overlap region to the size in the case of emphasizing fuel consumption based on the request from the driver and the operating state of the engine 1, By setting the set time, the areas Ove3 and Ove4 are set as overlap areas.

  Even in this case, as in the case of the first embodiment, the size of the overlap region can be switched between the case of emphasizing fuel efficiency and the case of drivability. Even if there is, it is possible to ensure the running performance that meets the high level.

  Similarly to the first embodiment, when the vehicle is traveling in the fixed gear ratio mode, the target driving force increases when the driver depresses the accelerator, etc., and the continuously variable gear ratio is changed from the fixed gear ratio mode. When switching to the mode, in order to increase the driving force smoothly, it is preferable to make the overlap region for holding the continuously variable transmission ratio mode as small as possible.

  Therefore, as shown in FIG. 5, when the driving operation point moves from the point C4 to the point C5, that is, in the direction in which the target driving force increases, the ECU 50 changes from the fixed gear ratio mode region to the continuously variable gear ratio mode region. , The size of the overlap area Ove5 at this time is set to 0 by setting the set time at that time to 0, or the set time is set to the overlap area in other cases. By making it shorter than the set time, the size of the overlap region Ove5 is made smaller than the size of the overlap region in other cases. In this way, it is possible to immediately obtain the driving force required by the driver.

  According to the second embodiment described above, as in the first embodiment, the size of the overlap region is switched between the case of emphasizing fuel efficiency and the case of drivability. By making the overlap region larger than in the case of emphasizing fuel efficiency, it is possible to ensure a high level of driving performance that meets both the emphasis on fuel efficiency and drivability.

It is a figure showing the schematic structure of the hybrid vehicle concerning this embodiment. It is a figure which shows the structure of a motor generator and a power split device. It is a map which shows the driving | running area | region prescribed | regulated with a target drive force and a vehicle speed. It is a map which shows the driving | running area | region prescribed | regulated with the target drive force and vehicle speed which concern on 1st Embodiment. It is a map which shows the driving | running area | region prescribed | regulated with the target drive force and vehicle speed which concern on 2nd Embodiment. It is a flowchart which shows the control process of the hybrid vehicle which concerns on 2nd Embodiment.

Explanation of symbols

MG1, MG2 Motor generator 1 Engine 5 Dog clutch 7 Brake part 20 Power distribution mechanism 50 ECU

Claims (2)

Applied to a hybrid vehicle having an engine and a motor generator as a drive source and configured to be able to switch between two continuously variable gear ratio modes and a fixed gear ratio mode. A control apparatus for a hybrid vehicle comprising control means for switching a gear ratio mode according to the position of the current driving operation point on a map defined by a target driving force and a vehicle speed, in which a fixed gear ratio mode region is set Because
Between the continuously variable gear ratio mode region and the fixed gear ratio mode region, an overlap region that prohibits switching of the gear ratio mode is set,
Wherein when the operating state of the engine is lean burn, as compared to the operating state of the engine is not lean burn control of the hybrid vehicle, characterized in that to increase the overlap region apparatus.   The control means reduces the overlap region when the current driving operation point shifts from the fixed gear ratio mode region to the continuously variable gear ratio mode region in a direction in which the target driving force increases. The hybrid vehicle control device according to claim 1.

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