JP2012153320A - Hybrid vehicle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the time until completion of engine start while preventing the effect of torque decrease shock upon the start of an engine.SOLUTION: This hybrid vehicle control device includes: an engine 1, a motor 2; a first clutch 4 switching between an HEV mode and an EV mode; a second clutch 5 subjected to slip engagement upon mode transition; and an engine start control means (Fig.10). When the torque at the request of start being the engagement torque of the second clutch 5 at the request of the engine start is equal to or less than shock non-occurrence torque due to torque decrease of the second clutch 5, the engine start control means (Fig.10) sets torque upon the mode transition being engagement torque of the second clutch 5 upon the mode transition to a smaller value as compared with a case in which the torque at the request of the start is larger than the shock non-occurrence torque.

Description

  The present invention relates to a hybrid vehicle control device that slip-engages a friction element between a motor and drive wheels when a mode transition is made from an electric vehicle mode to a hybrid vehicle mode based on an engine start request.

  Conventionally, at the time of mode transition from the electric vehicle mode to the hybrid vehicle mode, after slipping by reducing the engagement torque of the second clutch interposed between the motor and the drive wheel, it is interposed between the engine and the motor. There is known a control apparatus for a hybrid vehicle that engages the first clutch and starts the engine (see, for example, Patent Document 1).

JP 2007-131071 A

  However, in the conventional device, when the second clutch is slipped, the amount of reduction in the engagement torque in the second clutch is limited in order to prevent occurrence of a torque loss shock due to excessive reduction in the engagement torque of the second clutch. It was. Therefore, there is a problem that it takes time from the engine start request to the slip of the second clutch, and the time until the engine start is completed becomes long.

  The present invention has been made paying attention to the above problem, and provides a control device for a hybrid vehicle capable of reducing the time until the engine start is completed while suppressing the influence of torque loss shock at the time of engine start. With the goal.

In order to achieve the above object, a control apparatus for a hybrid vehicle of the present invention includes an engine, a motor, a mode switching unit, a friction element, and an engine start control unit.
The mode switching means switches between a hybrid vehicle mode using an engine and a motor as a drive source and an electric vehicle mode using a motor as a drive source. The friction element is slip-engaged at the time of mode transition from the hybrid vehicle mode to the electric vehicle mode based on the engine start request.
The engine start control means is configured such that when the start request torque, which is the engagement torque of the friction element at the start of the engine, is equal to or less than the non-shock generation torque due to the torque loss of the friction element, the start request torque is greater than the non-shock generation torque. The torque at the time of mode transition, which is the engagement torque of the friction element at the time of mode transition, is set to a smaller value than when it is large.

Therefore, when the start request torque is equal to or less than the non-shock generation torque, the engine start control is performed with the mode transition torque set to a smaller value than when the start request torque is larger than the non-shock generation torque.
Therefore, when the torque at the time of the start request is equal to or less than the torque at which the shock is not generated, the friction element quickly slips by reducing the torque at the time of mode transition. On the other hand, since the fastening torque of the friction element at the time of the engine start request is equal to or less than the shock non-occurrence torque due to the torque loss of the friction element, even if the friction element slips quickly, the influence of the torque loss shock is small.
For this reason, the time until the slip of the friction element starts can be shortened only in scenes where the effect of torque loss shock is small. As a result, the time until completion of engine start is reduced while suppressing the effect of torque loss shock. can do.

It is a powertrain block diagram which shows the powertrain of the hybrid vehicle to which the control apparatus of Example 1 was applied. It is a control system block diagram which shows the control system of the hybrid vehicle to which the control apparatus of Example 1 was applied. FIG. 3 is a calculation block diagram illustrating an integrated controller according to the first embodiment. It is a map figure which shows the target steady torque map (a) and MG assist torque map (b) which are used with the control apparatus of Example 1. It is a map figure which shows the engine start stop line map used with the control apparatus of Example 1. FIG. It is a map figure which shows the electric power generation request output map during driving | running | working with respect to battery SOC used with the control apparatus of Example 1. It is a characteristic view which shows the optimal fuel consumption line of the engine used with the control apparatus of Example 1. FIG. 3 is a shift map diagram illustrating an example of shift lines in the automatic transmission according to the first embodiment. It is explanatory drawing which shows an example of the driving mode transition in a hybrid vehicle. 3 is a flowchart showing the configuration and flow of an engine start control process executed by the integrated controller of the first embodiment. 6 is a time chart showing characteristics of second clutch (CL2) engagement torque, motor torque, motor rotation speed, engine rotation speed, brake pedal force, and vehicle speed when an engine start request is generated when the hybrid vehicle is stopped. The characteristics of the second clutch (CL2) engagement torque, motor torque, motor speed, engine speed, brake pedal force, and vehicle speed when an engine start request is generated when the hybrid vehicle equipped with the control device of the first embodiment is stopped. It is a time chart which shows.

  Hereinafter, the best mode for realizing a control device for a hybrid vehicle of the present invention will be described based on a first embodiment shown in the drawings.

First, the configuration will be described.
FIG. 1 is a power train configuration diagram illustrating a power train of a hybrid vehicle to which the control device of the first embodiment is applied. Hereinafter, the powertrain configuration will be described with reference to FIG.

  As shown in FIG. 1, the power train system of the hybrid vehicle of the first embodiment includes an engine 1, a motor generator 2 (motor; hereinafter referred to as “MG”), and an automatic transmission 3 (hereinafter referred to as “ AT ”), a first clutch 4 (mode switching means; hereinafter referred to as“ CL1 ”), a second clutch 5 (friction element; hereinafter referred to as“ CL2 ”), A differential gear 6 and tires 7 and 7 (drive wheels) are provided. In other words, the engine 1 and 1 motor / 2 clutch are provided in the powertrain system.

  In the engine 1, the engine output shaft and the motor input shaft of the motor generator 2 are connected via a first clutch 4 having a variable torque capacity. In the motor generator 2, a motor output shaft and a transmission input shaft of the automatic transmission 3 are directly connected. The automatic transmission 3 is a stepped transmission having a plurality of friction elements, and tires 7 and 7 as drive wheels are connected to a transmission output shaft via a differential gear 6.

  The second clutch 5 selects one friction element among a plurality of friction elements by a clutch / brake having a variable torque capacity, which is responsible for power transmission in different transmissions according to the gear position of the automatic transmission 3. Used. As a result, the automatic transmission 3 synthesizes the power of the engine 1 input via the first clutch 4 and the power input from the motor generator 2 and outputs them to the tires 7 and 7.

  As the first clutch 4, for example, a dry single plate clutch or a dry multi-plate clutch that can continuously control the oil flow rate and hydraulic pressure with a proportional solenoid may be used. As the second clutch 5, for example, a wet multi-plate clutch or a wet multi-plate brake that can continuously control the oil flow rate and hydraulic pressure with a proportional solenoid may be used.

  This power train system has two operation modes according to the connection state of the first clutch 4. When the first clutch 4 is disconnected and the CL1 is released, the vehicle is in an electric vehicle mode (hereinafter referred to as “EV mode”) that runs only with the power of the motor generator 2. This EV mode is selected when the required drive torque is low and the battery SOC is secured. On the other hand, in the CL1 engagement state in which the first clutch 4 is connected, a hybrid vehicle mode (hereinafter referred to as “HEV mode”) that runs with the power of the engine 1 and the motor generator 2 is set. This HEV mode is selected when the required drive torque is high or when the battery SOC is insufficient. When an engine start request is generated in the EV mode, the EV mode shifts to the HEV mode through a mode transition state such as “engine start mode” → “WSC mode (drive torque control mode)” (see FIG. 9).

  Further, the power train includes an engine rotation sensor 10 that detects the rotation speed of the engine 1, an MG rotation sensor 11 that detects the rotation speed of the motor generator 2, and an AT that detects the input shaft rotation speed of the automatic transmission 3. An input rotation sensor 12 and an AT output rotation sensor 13 for detecting the output shaft rotation speed of the automatic transmission 3 are provided.

  FIG. 2 is a control system configuration diagram illustrating a hybrid vehicle control system to which the control device of the first embodiment is applied. Hereinafter, the control system configuration will be described with reference to FIG.

  As shown in FIG. 2, the control system of the first embodiment includes an integrated controller 20, an engine controller 21, a motor controller 22, an inverter 8, a battery 9, a solenoid valve 14, a solenoid valve 15, and an accelerator opening. A degree sensor 17, a brake hydraulic pressure sensor 23, and an SOC sensor 16.

  The integrated controller 20 performs integrated control of operating points of the powertrain system. In this integrated controller 20, the drive desired by the driver according to the accelerator opening APO, the battery SOC, and the vehicle speed VSP (proportional to the automatic transmission output shaft rotational speed detected by the AT output rotation sensor 13). Select the operation mode that can realize the power. Then, according to the selected operation mode, the target MG torque or the target MG rotation speed is commanded to the motor controller 22, the target engine torque is commanded to the engine controller 21, and the drive signal is commanded to the solenoid valves 14 and 15. .

  The engine controller 21 controls the engine 1. The motor controller 22 controls the motor generator 2. The inverter 8 drives the motor generator 2. The battery 9 stores electrical energy. The solenoid valve 14 controls the hydraulic pressure of the first clutch 4. The solenoid valve 15 controls the hydraulic pressure of the second clutch 5. The accelerator opening sensor 17 detects an accelerator opening (APO). The brake oil pressure sensor 23 detects brake oil pressure (BPS). The brake pedal force is proportional to the brake hydraulic pressure BPS detected by the brake hydraulic pressure sensor 23. The SOC sensor 16 detects the battery SOC which is the charge capacity state of the battery 9.

  FIG. 3 is a calculation block diagram illustrating the integrated controller according to the first embodiment. The configuration of the integrated controller 20 will be described below based on FIG.

  As shown in FIG. 3, the integrated controller 20 includes a target drive torque calculation unit 100, a mode selection unit 200, a target power generation output calculation unit 300, an operating point command unit 400, and a shift control unit 500. ing.

  The target drive torque calculation unit 100 uses the target steady torque map shown in FIG. 4 (a) and the MG assist torque map shown in FIG. 4 (b) to calculate the target drive torque from the accelerator opening APO and the vehicle speed VSP. A certain target steady torque and MG assist torque are calculated.

  The mode selection unit 200 uses the vehicle speed VSP and the accelerator opening APO, the engine start / stop line map shown in FIG. 5, and the battery SOC to search for an optimal operation mode (HEV mode, EV mode), The searched driving mode is selected as the target driving mode. In the engine start / stop line map, the engine start line and the engine stop line have low battery SOC, as represented by the characteristics of the engine start line (SOC high, SOC low) and engine stop line (SOC high, SOC low). As a result, the accelerator opening APO is set as a characteristic that decreases in a decreasing direction. The engine start request is generated when the engine start line shown in FIG. 5 exceeds the operating point by the accelerator opening APO and the vehicle speed VSP in the EV mode state, or when the battery SOC falls below the lower limit threshold. .

  The target power generation output calculation unit 300 calculates a target power generation output from the battery SOC using the traveling power generation request output map shown in FIG. Further, an output required to increase the engine torque from the current operating point to the optimum fuel consumption line shown in FIG. 7 is calculated, and an output smaller than the target power generation output is added to the engine output as a required output.

  The operating point command unit 400 inputs an accelerator opening APO, a target drive torque (target steady torque, MG assist torque), a target travel mode, a vehicle speed VSP, and a target power generation output. Then, using these input information as the operating point reaching target, a transient target engine torque, target MG torque, target CL2 torque capacity, target AT shift, and CL1 solenoid current command are calculated.

  The shift control unit 500 calculates an AT solenoid current command for driving and controlling a solenoid valve in the automatic transmission 3 so as to achieve these from the target CL2 torque capacity and the target AT shift. FIG. 8 shows an example of a shift line map used in shift control. The shift control determines which gear stage is to be changed from the current gear stage to the next gear stage based on the driving point based on the vehicle speed VSP and the accelerator opening APO and the shift line map. When the operating point crosses the upshift line (solid line in FIG. 8) or the downshift line (dotted line in FIG. 8) of the shift line map, an upshift request or a downshift request is issued, and the automatic transmission 3 corresponding to the shift request. The frictional element is engaged / released to change the speed. In the first embodiment, the gear ratio change in the inertia phase region is changed by adding the rotation speed control by the motor generator 2 provided on the input side of the automatic transmission 3 at the time of shifting, as compared with the shift control only by the hydraulic control. Shifting control is performed smoothly.

  FIG. 10 is a flowchart showing the configuration and flow of an engine start control process (engine start control means) executed by the integrated controller of the first embodiment. Hereinafter, each step of FIG. 10 will be described.

In step S1, it is determined whether an engine start condition is satisfied in the EV mode. If YES (condition is satisfied), the process proceeds to step S2. If NO (condition is not satisfied), step S1 is repeated.
Here, establishment of the engine start condition means that an engine start request is generated. It is determined that the engine start condition is satisfied (the engine start request is generated) when the operating point by the accelerator opening APO and the vehicle speed VSP exceeds the engine start line shown in FIG. 5 or when the battery SOC falls below the lower limit threshold.

  In step S2, following the determination that the engine start condition is satisfied in step S1, the operation mode is shifted from the EV mode to the engine start mode which is the mode transition state, and the process proceeds to step S3.

In step S3, following the transition to the engine start mode in step S2, the "start request torque", which is the engagement torque in the second clutch 5 when the engine start condition is satisfied (when the engine start is requested), It is determined whether the torque is equal to or less than “torque”. If YES (startup request torque ≦ shock non-occurrence torque), the process proceeds to step S4. If NO (startup request torque> shock non-occurrence torque), the process proceeds to step S6.
Here, if the engagement torque in the second clutch 5 is excessively reduced from a certain value or more, the transmission torque capacity in the second clutch 5 is too low and a shock due to torque loss occurs. Note that “torque loss” means that at least a part of the drive torque transmitted from the drive source to the drive wheels is interrupted by the second clutch 5 due to a decrease in the transfer torque capacity of the second clutch 5, and the drive torque of the vehicle is suddenly reduced. It means to decrease.
On the other hand, “shock non-occurrence torque” means that the effect of torque loss is low even if the engagement torque of the second clutch 5 is reduced to the equivalent of zero Nm (the vehicle shock due to torque loss hardly occurs or This is a fastening torque value that can be determined to be an acceptable level even if the occurrence of. This “shock non-occurrence torque” is set to an arbitrary value in advance in accordance with the travel range at the time of engine start request. For example, when the engine start request is in the drive range (D range), the “shock non-occurrence torque” is set to a predetermined value α, and when the engine start request is in the reverse range (R range), the “shock non-occurrence torque” is set. Is set to a predetermined value β (> α).
Here, the magnitude of the shock due to the torque loss varies depending on the conditions for reducing the transmission torque capacity of the second clutch 5. Specifically, it varies depending on the magnitude of change before and after the transmission torque capacity is reduced, the rate of change when the transmission torque capacity is reduced, the temperature of the hydraulic fluid for operating the second clutch 5, and the like. . Therefore, it is preferable that the “shock non-generation torque” is obtained in advance by an experiment or the like.

In step S4, it is determined whether or not the vehicle is stopped following the determination that the starting request torque in step S3 ≦ the shock non-occurrence torque. If YES (stop the vehicle), the process proceeds to step S5. If NO (vehicle travel), the process proceeds to step S6.
Here, whether or not the vehicle is stopped is determined by whether or not the vehicle speed VSP obtained in proportion to the automatic transmission output shaft rotation speed detected by the AT output rotation sensor 13 is less than the stop determination threshold value (≈zero). Judgment by If the vehicle speed VSP is less than the stop determination threshold, it is determined that the vehicle is stopped.

In step S5, following the determination that the vehicle is stopped in step S4, it is determined whether the brake is ON. If YES (brake ON), the process proceeds to step S7. If NO (brake OFF), the process proceeds to step S6.
Here, whether or not the brake is ON is determined by whether or not the brake depression force obtained in proportion to the brake hydraulic pressure (BPS) detected by the brake hydraulic pressure sensor 23 is equal to or greater than the brake ON determination threshold value. If the brake pedal force is greater than or equal to the brake ON determination threshold, it is determined that the brake is ON.

In step S6, following either one of the determination that the torque at the time of the start request in step S3> the shock non-occurrence torque, the determination that the vehicle travels in step S4, and the brake OFF operation in step S5, “Transition torque” is set to “first torque”, engine start control is performed, and the process proceeds to the end.
Here, in the engine start control, first, the engagement torque in the second clutch 5 is reduced to cause the second clutch 5 to slip-engage. When it is determined that the second clutch 5 has slipped, the first clutch 4 is put into a semi-engaged state, the motor generator 2 is used as a starter motor, and the motor torque is increased to crank the engine 1. As a result, the engine speed starts to increase. On the other hand, the engagement torque of the second clutch 5 is controlled so as to be a required drive torque determined according to the vehicle state and the driver operation state after the second clutch 5 slips. When the engine speed reaches a speed at which the initial explosion is possible, the engine 1 is combusted by fuel supply or ignition, and the first clutch 4 is completely engaged when the motor speed and the engine speed become close. Thereby, the engine start mode is shifted to the WSC mode, and the engine start control is completed. After that, the second clutch 5 is locked up and the mode transition is completed by shifting to the HEV mode.
In step S6, during engine start control, the “mode transition torque” that is the engagement torque in the second clutch 5 when the second clutch 5 is slip-engaged is reduced to the “first torque”. The “first torque” is a predetermined intermediate pressure at which the second clutch 5 is not released until the engagement torque becomes equal to zero Nm, and a torque loss shock does not occur, depending on the vehicle state and the driver operation state. The value is slightly lower than the determined required driving torque. Thus, the torque reduction amount is limited so that the “mode transition torque” does not become smaller than the “first torque”, and the transmission torque capacity in the second clutch 5 is ensured.

In step S7, following the determination that the brake is ON in step S5, “mode transition torque” is set to “second torque”, engine start control is performed, and the process proceeds to the end.
Here, the engine start control is the same as that in step S6.
On the other hand, in step S7, in order to slip-engage the second clutch 5 during engine startup, the “mode transition torque” is reduced to “second torque”. This “second torque” is a value smaller than the “first torque” set in step S6, and here, the fastening torque is a value corresponding to substantially zero Nm. That is, when the start request torque is equal to or less than the non-shock torque, the torque reduction amount in the “mode transition torque” increases.

Next, the operation will be described.
First, “the problem of the comparative example” will be described. Next, the “engine start control action” in the hybrid vehicle control device of the first embodiment is as follows: (1) When the start request torque is greater than the non-shock torque, (2) The start request torque is less than the non-shock torque At that time, the explanation will be divided.

[Problems of comparative example]
FIG. 11 is a time chart showing characteristics of the second clutch (CL2) engagement torque, motor torque, motor rotation speed, engine rotation speed, brake pedal force, and vehicle speed when an engine start request is generated when the hybrid vehicle is stopped. . In the figure, the solid line indicates the state when the hybrid control apparatus of the first embodiment is applied, and the broken line indicates the state of the first comparative example.

  At the time of mode transition from the EV mode to the HEV mode based on the engine start request, the amount of reduction in the engagement torque in the second clutch for slipping the second clutch is limited so that the shock due to torque loss in the second clutch does not occur This is referred to as Comparative Example 1. That is, in the first comparative example, the second clutch engagement torque at the time of mode transition (hereinafter referred to as “mode transition torque”) is set to “first torque” which is a predetermined intermediate pressure at which torque loss shock does not occur.

  In the case of this comparative example 1, since the amount of engagement torque reduction at the time of mode transition is limited with respect to the second clutch engagement torque at the time of engine start request (hereinafter referred to as “startup request torque”), the second The clutch is not released too much and the occurrence of torque loss shock is prevented. That is, the torque loss shock at the time of mode transition is caused by a torque difference between the torque at the time of start request and the torque at the time of mode transition. Here, by limiting the amount of reduction in the engagement torque at the time of mode transition, the torque difference between the torque at the time of start request and the torque at the time of mode transition does not increase, and the occurrence of shock is suppressed.

  However, as shown by a broken line in FIG. 11, for example, when the engine start request is generated due to a shortage of the battery SOC while the vehicle is stopped, when the start request torque is originally low, the torque at the mode transition is set. Regardless, the torque difference does not widen. That is, it is not necessary to consider a shock due to torque loss in the second clutch.

  On the other hand, in Comparative Example 1, the torque at the time of mode transition is set even if the torque at the time of the start request is originally low because the torque at the time of mode transition is set to “first torque” by limiting the amount of reduction in the engagement torque. Cannot be set to a small value. Therefore, the time until the second clutch slips increases (in FIG. 11, time t1 to time t2), and the time until the engine start is completed (in FIG. 11, the engine start is completed at time t3) becomes longer. It was.

  On the other hand, when the mode is changed from the EV mode to the HEV mode, the amount of reduction in the engagement torque in the second clutch for slipping the second clutch is not limited, and is reduced to zero Nm equivalent as Comparative Example 2.

  In the case of the comparative example 2, the torque at the time of mode transition is reduced to zero Nm equivalent regardless of the magnitude of the torque at the time of starting request. Therefore, the second clutch slips immediately. However, when the torque at the time of start request is large, the torque difference from the torque at the time of mode transition widens, and a large torque loss shock occurs.

  As described above, in the case of the comparative example 1, by limiting the torque reduction amount at the time of mode transition, there arises a problem that it takes an engine start time when it is not necessary to consider the torque loss shock. Moreover, in the case of the comparative example 2, since the torque reduction amount at the time of mode transition is not limited, there arises a problem that a large torque loss shock occurs when the torque at the start request is large. Thus, the two required performances such as the suppression of the impact of the falling shock and the shortening of the engine start time cannot be satisfied at the same time, and conversely, the two problems are exposed at the same time.

[Engine start control action]
(1) When the start request torque is larger than the non-shock generating torque FIG. 12 shows the second clutch (CL2) engagement torque when the engine start request is generated when the hybrid vehicle equipped with the control device of the first embodiment is stopped. It is a time chart which shows each characteristic of motor torque, motor rotation speed, engine rotation speed, brake pedal effort, and vehicle speed. In the figure, the solid line indicates when the start request torque is greater than the non-shock torque, and the broken line indicates when the start request torque is less than the non-shock torque.

  At time t10 shown in FIG. 12, the hybrid vehicle is in a vehicle stop state in the EV mode in which the engine 1 is stopped, and the transmission drive torque in the second clutch 5 is relatively high. That is, the second clutch engagement torque at time t10 is higher than the shock non-occurrence torque.

  Therefore, when an engine start request is generated at time t11 due to a shortage of battery SOC or the like, the start request torque, which is the engagement torque of the second clutch 5 at this time, is based on the non-shock generating torque (here, predetermined values α and β). Is also a large value.

  That is, in the flowchart of FIG. 10, the process proceeds from step S1 to step S2 to step S3, and then proceeds to step S6. As a result, the torque at the time of mode transition, which is the second clutch engagement torque in the engine start mode, is set to “first torque”, which is a predetermined intermediate pressure at which no torque loss shock occurs, and engine start control is performed.

  For this reason, the second clutch engagement torque after time t11 is set to “first torque”. As a result, the amount of reduction in the engagement torque in the second clutch 5 in the engine start mode is limited, and the torque difference between the start request torque and the mode change torque is widened even when the start request torque is relatively high. Is suppressed. As a result, a large torque loss shock does not occur, and the influence of the torque loss shock is suppressed.

Then, at the same time as the second clutch engagement torque is set to the “first torque”, the motor torque starts to increase.
At this time, the motor torque change rate, which is the absolute value of the input torque to the second clutch 5, is larger than the motor torque change rate when the mode transition torque is set to the "second torque". Set to. That is, as shown in FIG. 12, the characteristic gradient θ1 when increasing the motor torque from time t11 is larger than the characteristic gradient θ2 of increasing motor torque when the mode transition torque is set to “second torque”. To do.
As a result, the torque input to the second clutch 5 quickly increases, and an increase in time until the slip of the second clutch 5 occurs is prevented.

Further, at time t13, it is determined that the second clutch 5 has slipped when the motor rotation speed reaches the predetermined rotation speed, and the engagement torque of the second clutch 5 is gradually increased.
At this time, the motor torque that is the absolute value of the input torque to the second clutch 5 is maintained at a predetermined value δ necessary for slip engagement of the second clutch 5. This “predetermined value δ” is set to a larger value than the motor torque when the mode transition torque is set to “second torque”. That is, as shown in FIG. 12, the predetermined value δ is set larger than the motor torque (predetermined value γ) when the mode transition torque is set to the “second torque”.
Thereby, the absolute value of the torque input to the second clutch 5 becomes a relatively large value, and the slip state of the second clutch 5 is reliably maintained.

  When the slip of the second clutch 5 is confirmed at time t15, the first clutch 4 is brought into a semi-engaged state, and the engine 1 is cranked using the motor generator 2 as a starter motor. After that, when the engine speed reaches a speed at which the initial explosion is possible, the engine 1 is combusted and the first clutch 4 is completely engaged at time t16 to end the engine start mode and shift to the WSC mode. .

(2) When the required torque at start is equal to or less than the non-shock torque, at time t10 shown in FIG. 12, the hybrid vehicle is in the EV mode in which the engine 1 is stopped, and the vehicle is operated by turning on the brake while traveling in the D range. Is in a stopped state.

  When the battery SOC falls below the lower limit threshold due to the use of an air conditioner or the like at time t11, an engine start request is generated. At this time, the vehicle is stopped (vehicle speed VSP <stop determination threshold and brake pedal force> brake ON determination threshold), and the torque at start request that is the second clutch engagement torque at the time of engine start request (time t11) Is lower than the shock non-occurrence torque (here, the predetermined value α).

  That is, in the flowchart of FIG. 10, the process proceeds from step S 1 → step S 2 → step S 3 → step S 4 → step S 5 → step S 7, the mode transition torque is set to “second torque”, and engine start control is performed. .

Thereby, the engagement torque of the second clutch 5 after the time t11 is set to “second torque” which is smaller than the “first torque” and substantially equal to zero Nm. At the same time, the motor torque starts to increase.
At this time, the rate of change of the motor torque, which is the absolute value of the input torque to the second clutch 5, is smaller than the rate of change of the motor torque when the mode transition torque is set to "first torque". Set to. That is, as shown in FIG. 12, the characteristic gradient θ2 when increasing the motor torque from time t11 is smaller than the characteristic gradient θ1 of increasing motor torque when the mode transition torque is set to “first torque”. To do.
As a result, the torque input to the second clutch 5 gradually increases, and when the second clutch 5 slips, a thrusting shock caused by the input torque to the second clutch 5 is prevented.

  When the motor torque reaches a predetermined value at time t12, the motor rotation speed starts increasing.

When the motor rotation speed reaches a predetermined rotation speed at time t13, it is determined that the differential rotation in the second clutch 5 becomes a predetermined value and the second clutch 5 has slipped, and the engagement torque of the second clutch 5 is gradually increased. .
At this time, the motor torque that is the absolute value of the input torque to the second clutch 5 is maintained at a predetermined value γ necessary for slip engagement of the second clutch 5. This “predetermined value γ” is set to a smaller value than the motor torque when the mode transition torque is set to “first torque”. That is, as shown in FIG. 12, the predetermined value γ is made smaller than the motor torque (predetermined value δ) when the mode transition torque is set to “first torque”.
As a result, the absolute value of the torque input to the second clutch 5 becomes a relatively small value, and when the second clutch 5 slips, a push-up shock caused by the input torque to the second clutch 5 is prevented. The

  When the slip of the second clutch 5 is confirmed at time t14, the first clutch 4 is put into a semi-engaged state, and the motor torque is increased to a level necessary for engine cranking. As a result, the engine 1 is cranked using the motor generator 2 as a starter motor.

  As a result, the engine speed starts increasing from time t15. Thereafter, when the engine speed reaches a speed at which the initial explosion is possible, the engine 1 is burned. When the motor speed and the engine speed become close at time t16, the first clutch 4 is completely engaged, and the engine start mode is set. To exit to WSC mode.

As described above, in the first embodiment, when the start request torque is equal to or less than the non-shock torque, the mode transition torque is set to a smaller value than when the start request torque is larger than the non-shock torque. Adopted the configuration. That is, when the start request torque is equal to or less than the shock non-occurrence torque, the mode transition torque is set to “second torque” which is smaller than “first torque”.
With this configuration, in a scene where it is not necessary to consider the impact of shock due to torque loss of the second clutch 5, when the second clutch 5 is slipped, the engagement torque of the second clutch 5 is greatly reduced. . Therefore, the second clutch 5 is almost released at the same time as the engine start request is generated, and is quickly brought into the slip state (time t11 to time t13 in FIG. 12). This shortens the time until the second clutch 5 slips only in the scene where the torque loss shock does not occur, and the time until the engine start is completed (in FIG. 12, the engine start is completed at time t16). . Furthermore, since the engine 1 is started in a short time, the time until the motor generator 2 is driven as a generator by the driving force of the engine 1 to generate power is shortened. Further, the second clutch 5 slips quickly, so that the motor load is reduced, and motor energy is saved, that is, energy saving is achieved.

On the other hand, when the start request torque is larger than the non-shock torque, the mode transition torque is set to “first torque” which is a predetermined intermediate pressure at which no torque loss shock occurs.
With this configuration, in the normal scene where it is necessary to consider the influence of the torque loss shock, when the second clutch 5 is slipped, the amount of reduction in the engagement torque in the second clutch 5 is limited. Therefore, in the scene where the torque loss shock occurs in the second clutch 5, the influence of the torque loss shock is reliably suppressed.

Further, in the first embodiment, a configuration is adopted in which the mode transition torque is set to the “second torque” only when the vehicle is stopped, as determined in step S4 of the flowchart shown in FIG.
With this configuration, when the vehicle is traveling, the engagement torque of the second clutch 5 is greatly reduced, and the occurrence of torque loss is prevented.

Further, in the first embodiment, as in the determination in step S5 of the flowchart shown in FIG. 10, the mode transition torque is set to “second torque” only when the brake device is turned on. Adopted.
With this configuration, it is possible to prevent a vehicle stoppage from being determined in an extremely low vehicle speed state that cannot be detected by the AT input rotation sensor 12, and to prevent torque loss during vehicle travel. That is, it is possible to prevent the occurrence of torque loss due to an erroneous determination in an undetectable region of the vehicle speed detection sensor mounted on the vehicle.

In the first embodiment, as shown in the time chart of FIG. 12, the non-shock generating torque is set to a predetermined value α during traveling in the D range, and when the engine start request is in the reverse range (R range). Adopted a configuration in which the non-shock generating torque is set to a predetermined value β (> α).
With this configuration, the condition that does not cause a shock due to the torque loss of the second clutch 5 according to the travel range, that is, the value of the shock non-occurrence torque is set to an optimal value, and the influence of the torque loss shock is more appropriately affected. It is suppressed.

Next, the effect will be described.
In the hybrid vehicle control device of the first embodiment, the following effects can be obtained.

(1) an engine 1, a motor (motor generator) 2, a hybrid vehicle mode (HEV mode) provided at a connecting portion between the engine 1 and the motor 2 and using the engine 1 and the motor 2 as drive sources; The mode switching means (first clutch) 4 for switching between the electric vehicle mode (EV mode) using the motor 2 as a drive source, and the motor 2 and drive wheels (tires) 7 and 7 are interposed between the engine 2 and the engine. A friction element (second clutch) 5 that is slip-engaged at the time of mode transition from the electric vehicle mode to the hybrid vehicle mode based on a start request;
When the start request torque, which is the fastening torque of the friction element at the start of the engine, is equal to or less than the non-shock generation torque due to the torque loss of the friction element 5, the start request torque is greater than the non-shock generation torque. The engine start control means (FIG. 10) for setting the mode transition torque, which is the engagement torque of the friction element at the time of the mode transition, to a small value.
For this reason, it is possible to shorten the time until the engine start is completed while preventing the influence of the torque loss shock at the time of engine start.

(2) The engine start control means (FIG. 10) sets the mode transition time torque to the first torque when the start request torque is greater than the non-shock generation torque, and the start request torque is the shock request torque. When the torque is less than the non-generated torque, the mode transition torque is set to a second torque that is smaller than the first torque.
For this reason, in addition to the effect of (1), the time until the friction element slips can be surely shortened only in a scene where a shock due to torque loss of the friction element does not occur.

(3) The engine start control means (FIG. 10) is configured to set the mode transition torque to the second torque when the vehicle is stopped (step S4).
For this reason, in addition to the effect of (1) or (2), it is possible to prevent a torque loss shock from occurring during traveling of the vehicle.

(4) The engine start control means (FIG. 10) is configured to set the torque at the time of mode transition to the second torque when the brake is operated (step S5).
For this reason, in addition to the effects (1) to (3), it is possible to prevent a torque loss shock from occurring during traveling of the vehicle.

(5) The engine start control means (FIG. 10) uses the absolute value (predetermined value γ) of the input torque to the friction element 5 when the mode transition torque is set to the second torque as the mode transition. The time torque is set to a value smaller than the absolute value (predetermined value δ) of the input torque to the friction element 5 when the first torque is set.
For this reason, in addition to the effects (1) to (4), when the second clutch 5 slips, it is possible to prevent a push-up shock caused by the input torque to the second clutch 5.

(6) The engine start control means (FIG. 10) indicates the rate of change (θ2) of the input torque to the first friction element 5 when the torque at the mode transition is set to the second torque, at the time of the mode transition. The torque is set to a value smaller than the rate of change (θ1) of the input torque to the friction element 5 when the torque is set to the first torque.
For this reason, in addition to the effects (1) to (5), it is possible to prevent a push-up shock caused by the input torque to the second clutch 5.

(7) The engine start control means (FIG. 10) is configured to set the value of the non-shock generating torque according to the travel range.
For this reason, in addition to the effects (1) to (6) above, the value of the shock non-occurrence torque is set to an optimum value according to the travel range, and the influence of the torque loss shock can be further appropriately suppressed.

  As mentioned above, although the control apparatus of the hybrid vehicle of this invention was demonstrated based on Example 1, it is not restricted to this Example 1 about a concrete structure, The invention which concerns on each claim of a claim Design changes and additions are permitted without departing from the gist of the present invention.

  In the first embodiment, when the start request torque is larger than the non-shock generation torque, the mode transition torque is set to “first torque”, and when the start request torque is equal to or less than the non-shock generation torque, The torque is set to “second torque”. However, if the torque at the time of start request is equal to or less than the torque at which no shock is generated, the torque at the time of mode transition is a relatively small value with respect to the torque at the time of mode transition when the torque at the time of start request is greater than the non-shock generated torque good. That is, the torque at the time of mode transition does not have to be a specific value, and may change or be corrected according to the vehicle situation, for example.

  In the first embodiment, a scene where an engine start request is generated when the vehicle is stopped is shown as an example of a scene where the torque loss shock of the second clutch 5 need not be taken into consideration. However, other examples may be used as long as the fastening torque in the second clutch 5 is low at the time of engine start request, and the present invention can be applied.

  In the first embodiment, the example in which the second clutch 5 is selected from the friction elements built in the stepped automatic transmission 3 is shown. However, the second clutch 5 may be provided separately from the automatic transmission 3, for example, an example in which the second clutch 5 is provided separately from the automatic transmission 3 between the motor generator 2 and the transmission input shaft, An example in which the second clutch 5 is provided separately from the automatic transmission 3 between the machine output shaft and the tires 7 and 7 is also included.

  In the first embodiment, the example in which the first clutch 4 is used as the mode switching means for switching between the HEV mode and the EV mode has been described. However, as the mode switching means for switching between the HEV mode and the EV mode, for example, a differential device or a power split device that exhibits a clutch function without using a clutch, such as a planetary gear, may be used.

1 Engine 2 Motor generator (motor)
3 Automatic transmission 4 First clutch (mode switching means)
5 Second clutch (friction element)
6 Differential gear 7 Tire (drive wheel)
8 Inverter 9 Battery 10 Engine rotation sensor 11 MG rotation sensor 12 AT input rotation sensor 13 AT output rotation sensor 14, 15 Solenoid valve 16 SOC sensor 17 Accelerator opening sensor 20 Integrated controller 21 Engine controller 22 Motor controller 23 Brake hydraulic pressure sensor

Claims (7)

Engine,
A motor,
Mode switching means provided at a connecting portion between the engine and the motor, and switching between a hybrid vehicle mode using the engine and the motor as a drive source and an electric vehicle mode using the motor as a drive source;
A friction element that is interposed between the motor and drive wheels and is slip-engaged at the time of mode transition from the electric vehicle mode to the hybrid vehicle mode based on an engine start request;
When the start request torque, which is the fastening torque of the friction element at the time of engine start request, is equal to or less than the non-shock generation torque due to the torque loss of the friction element, the start request torque is greater than the non-shock generation torque. In comparison, engine start control means for setting a mode transition torque, which is a fastening torque of the friction element at the time of the mode transition, to a small value;
A control means for a hybrid vehicle, comprising: In the hybrid vehicle control device according to claim 1,
The engine start control means sets the mode transition time torque to the first torque when the start request torque is larger than the shock non-occurrence torque, and when the start request torque is equal to or less than the shock non-occurrence torque, The hybrid vehicle control means, wherein the mode transition torque is set to a second torque that is smaller than the first torque. In the hybrid vehicle control device according to claim 1 or 2,
The hybrid vehicle control device, wherein the engine start control means sets the torque at the time of mode transition to the second torque when the vehicle is stopped. In the control apparatus of the hybrid vehicle as described in any one of Claims 1-3,
The engine start control means sets the torque at the time of mode transition to the second torque when the brake is operated. In the control apparatus of the hybrid vehicle as described in any one of Claims 1-4,
The engine start control means is configured to set the absolute value of the input torque to the friction element when the mode transition torque is set to the second torque, and the mode transition torque when the mode transition torque is set to the first torque. A control apparatus for a hybrid vehicle, characterized in that it is set to a value smaller than an absolute value of an input torque to a friction element. In the control apparatus of the hybrid vehicle as described in any one of Claims 1-5,
The engine start control means has a rate of change of input torque to the friction element when the mode transition time torque is set to the second torque, and the mode transition time torque is set to the first torque. A control apparatus for a hybrid vehicle, characterized in that it is set to a smaller value than a rate of change of input torque to the friction element. In the control apparatus of the hybrid vehicle as described in any one of Claims 1-6,
The hybrid vehicle control apparatus, wherein the engine start control means sets the value of the non-shock generating torque according to a travel range.