JP3852345B2 - Vehicle control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce and eliminate torque shocks by an engine by using a motor generator when restarting the engine from idling. <P>SOLUTION: An input shaft of an automatic transmission including a clutch element is coordinated with an engine integrally rotatable with the input shaft and a first motor generator. Like when the engine restarts from the idling, when accelerating the engine from idling in which an input revolving speed INPREV to the automatic transmission is smaller than the output revolving speed OUTREV, the motor generator is controlled by taking revolving speed instruction flag ODRMG1 as one so that the input revolving speed INPREV does not exceed the output revolving speed OUTREV. <P>COPYRIGHT: (C)2003,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control apparatus for a vehicle using a motor generator in combination with an engine as a drive source for drive wheels.
[0002]
[Prior art]
In recent vehicles, in order to mainly save fuel and reduce exhaust emissions, when the vehicle stops at an intersection or the like, an idle stop is preferably performed that automatically stops the engine under predetermined conditions. It has become. Japanese Patent Application Laid-Open No. 2001-182814 discloses a technique for operating a braking means in an automatic transmission at the time of restart from such an idle stop to prevent fluctuations in vehicle acceleration at the time of engine restart.
[0003]
[Problems to be solved by the invention]
The present invention does not use the braking means of the automatic transmission as in JP-A-2001-182814, but controls the operation of the motor generator linked to the drive wheels together with the engine so that the engine is restarted. A new technology for suppressing fluctuations in vehicle acceleration during engine acceleration is proposed. According to the present invention, since there is almost no need to add changes to the existing automatic transmission, its application is easy, and when the torque fluctuation is suppressed, the engine generator absorbs engine torque. Energy efficiency is improved.
[0004]
In a typical example of the present invention, when the vehicle is restarted from the idle stop, first, the sub drive wheels are driven by a sub motor different from the motor generator associated with the engine to shift to the creep running state. Therefore, the input rotational speed from the engine and motor generator to the automatic transmission is the output rotational speed of the automatic transmission corresponding to the input rotational speed (typically, the actual output rotational speed is multiplied by the gear ratio). When the engine restarts from this idling state, the engine speed rapidly increases immediately after the engine complete explosion, and the one-way clutch in the automatic transmission suddenly engages, causing an unpleasant shock. There is a risk of giving. Another object of the present invention is to reliably avoid a sudden engagement of the one-way clutch when the engine is restarted from the idling state.
[0005]
[Means for Solving the Problems]
A vehicle to which a control device of the present invention is applied includes an automatic transmission including a clutch element, an engine and a motor generator that are linked to an input shaft of the automatic transmission, and that can rotate integrally with the input shaft, and an automatic transmission. Drive wheels linked to the output shaft of the machine.
[0006]
According to a first aspect of the present invention, when the engine is accelerated from an idling state, the input rotational speed to the automatic transmission is smaller than the rotational speed obtained by multiplying the rotational speed of the output shaft of the automatic transmission by the speed ratio. The rotational speed of the motor generator is controlled so that the rotational speed does not exceed the rotational speed obtained by multiplying the rotational speed of the output shaft of the automatic transmission by the gear ratio, and the motor generator is linked to a sub drive wheel different from the drive wheel. And the idling state is a traveling state in which the sub driving wheels are driven by the sub motor.
[0008]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, at the time of the engine acceleration from an idling state, a torque generator of an engine can be effectively reduced and eliminated using a motor generator linked to the engine.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG. 1, this vehicle includes an engine 14 and a first motor generator 16 linked to a pair of rear wheels 10 as main drive wheels, and a sub motor linked to a pair of front wheels 12 as auxiliary drive wheels. And a second motor generator 18 as a front-rear wheel drive type hybrid vehicle.
[0010]
As is well known, the engine 14 generates driving force by burning fuel such as gasoline or light oil. The rotation shaft 16a (FIG. 2) of the first motor generator 16 is directly connected to the crankshaft of the engine 14, and always rotates integrally with the crankshaft. In this way, the engine 14 and the first motor generator 16 are integrally connected in series without using a clutch or the like, so that the configuration is simplified and the motor generator can be easily applied to an existing engine.
[0011]
The engine 14 and the first motor generator 16 are linked to the rear wheel 10 via a torque converter 19, an automatic transmission 20, a propeller shaft 22, a rear wheel differential gear 24, and an axle 26. Transmit power to and from. The second motor generator 18 is linked to the front wheel 12 via the front wheel differential gear 30, the axle 32, and the like, and transmits power to and from the front wheel 12. The first motor generator 16 and the second motor generator 18 are connected to a single battery 38 that stores electrical energy via an inverter 34, and a power running operation that is driven by electric power supplied from the battery 38, Both regenerative operation to charge is possible.
[0012]
The control unit 40 is a microcomputer system including a well-known CPU, ROM, RAM, and the like, and includes an engine control module ECM that controls the ignition timing, fuel injection amount, and the like of the engine 14, and the first motor generator 16. A first motor controller M / C-1 for controlling the operation, a second motor controller M / C-2 for controlling the operation of the second motor generator 18, and a hybrid control for comprehensively controlling the engine and the motor generator. Module HCM. The control unit 40 includes a vehicle speed VSP, a brake master cylinder pressure MCPRESS, an accelerator opening APO, and the like detected by various sensors such as a vehicle speed sensor 43, a master cylinder pressure sensor 44 for a brake pedal, and an accelerator opening sensor 45. Entered. Further, the control unit 40 determines the torque command value TTMG2 of the second motor generator 18, the estimated rear wheel driving force SRFDRV2, the torque command value TTMG1 of the first motor generator 16, and the first motor based on detection signals from various sensors. Estimated actual torque value STMG of the generator 16, input rotational speed INPREV to the automatic transmission 20, output rotational speed OUTREV of the automatic transmission 20 corresponding to this input rotational speed INPREV, engine rotational speed target value NSET, first motor generator 16 Rotational speed (= engine rotational speed) RNMG1 or the like is detected or calculated. The output rotational speed OUTREV typically corresponds to a value obtained by multiplying the actual output rotational speed of the output shaft 20b of the automatic transmission 20 by the speed ratio, that is, the output rotational speed before the shift. Therefore, in the driving state in which the driving force in the forward direction is transmitted from the engine 14 and the first motor generator 16 to the rear wheel 10 side, the output rotation speed OUTREV and the input rotation speed INPREV are substantially equal.
[0013]
FIG. 2 is a schematic configuration diagram showing the torque converter 19 and the 5-speed automatic transmission 20. This configuration is well known as described in January 2001; new model manual (F50-0) issued by Nissan Motor Co., Ltd .; NISSAN Cima F50 series vehicle, and will be briefly described here.
[0014]
The torque converter 19 rotates integrally with a pump impeller 19a that rotates integrally with the rotating shaft 16a of the first motor generator 16 and an input shaft 20a of the automatic transmission 20 via a stator 19d that includes a one-way clutch 19c. Torque is transmitted to and from the turbine liner 19b. The pump impeller 19a is provided with an oil pump 19e. The lockup clutch 49 connects and disconnects the rotating shaft 16 a of the first motor generator 16 and the input shaft 20 a of the automatic transmission 20.
[0015]
The automatic transmission 20 has three gear sets including a front gear set 51, a mid gear set 52, and a rear gear set 53 as a planetary gear set (planetary gear mechanism) including a sun gear, a planetary gear supported by a carrier, and an internal gear. . The front internal gear 51c operates (rotates) integrally with the input shaft 20a, the mid carrier 52b operates integrally with the output shaft 20b, and the front carrier 51b and rear internal gear 53c operate integrally. The mid internal gear 52c and the rear carrier 53b operate integrally.
[0016]
The automatic transmission 20 includes a plurality of brakes that fix rotating bodies such as shafts, gears, and carriers to a fixed body such as a housing, and a plurality of clutches that connect the pair of rotating bodies to each other. The front brake 54 fixes the front sun gear 51a. The input clutch 55 fixes the input shaft 20a, the front internal gear 51c, and the mid internal gear 52c. The direct clutch 56 connects the rear carrier 53b and the rear sun gear 53a. High & low reverse clutch 57 connects mid sun gear 52a and rear sun gear 53a. The reverse brake 58 fixes the rear carrier 53b. Forward brake 59 fixes mid sun gear 52a. The low coast brake 60 fixes the mid sun gear 52a.
[0017]
The first one-way clutch 61 allows the rear sun gear 53a to rotate in the forward rotation direction (the same rotation direction as the engine) with respect to the mid sun gear 52a and prohibits rotation in the reverse rotation direction. The forward one-way clutch (second one-way clutch) 62 is provided between the forward brake 59 and the mid sun gear 52a, and allows the mid sun gear 52a to rotate in the forward rotation direction and prohibits rotation in the reverse rotation direction. The third one-way clutch 63 allows rotation of the front sun gear 51a in the forward rotation direction and prohibits rotation in the reverse rotation direction.
[0018]
The operation of each clutch and brake is shown in FIGS. For example, when the shift lever is in the D or M2-M5 position, the driving force is transmitted from the input shaft 20a of the automatic transmission 20 to the output shaft 20b by engaging some of the one-way clutches 61-63. Conversely, when the vehicle travels coasting, etc., only when the high & low reverse clutch 57 and / or the low coast brake 60 are engaged, from the output shaft 20b of the automatic transmission 20 to the input shaft 20a. Torque in the opposite direction can be transmitted. When the torque is released, torque is not transmitted from the output shaft 20b to the input shaft 20a, and an idling state in which the output rotational speed OUTREV of the automatic transmission 20 exceeds the input rotational speed INPREV is possible. It becomes.
[0019]
5 to 7 are timing charts showing the characteristic control flow of the present embodiment. The control unit 40 calculates and stores the current operation mode according to the vehicle operation status, and drives and controls the engine 14 and the motor generators 16 and 18 according to the operation mode. When this operation mode is idle stop (= 3), the engine 14 is automatically stopped mainly for the purpose of improving fuel consumption. This idle stop condition is, for example, when the shift lever is in the D position, the vehicle speed VSP is 0 (zero), and the brake pedal is depressed. For example, depression of the brake pedal is detected based on the brake master cylinder pressure MCPRES. When release of the brake pedal is detected from this idle stop state, the state shifts to a creep running state 69 (see FIG. 5).
[0020]
Thus, in the creep running state from the idle stop state, the engine 14 is held in the stopped state (state in which fuel injection is not performed), and the second motor generator 18 receives the torque command value TTMG2 (creep in the forward direction). Power). At this time, as described above, since the idling of the input shaft 20a side with respect to the output shaft 20b side of the automatic transmission 20 is allowed, typically, when the vehicle actually starts moving, the output rotation of the automatic transmission 20 is typically performed. The idling state in which the speed OUTREV exceeds the input rotational speed INPREV is established.
[0021]
In this idling state, when it is detected that the accelerator pedal is depressed based on the accelerator opening APO, engine restart control described below is started. 8 to 10 are flowcharts showing the flow of this engine restart control. First, in S (step) 1, it is determined whether or not the accelerator opening APO is a small / medium accelerator opening (operation mode = 2) equal to or less than a predetermined first threshold value.
[0022]
S2 to S10 in FIGS. 5 and 8 show the flow of drive control for the small / medium accelerator opening. In S2, the rotation speed command flag ODRMG1 of the first motor generator 16 is set to 1. Thus, the first motor generator 16 is controlled in rotational speed so that the input rotational speed INPREV does not exceed the output rotational speed OUTREV so as to gradually increase toward the output rotational speed OUTREV. The first motor generator 16 controls the rotational speed of the rotational shaft so as to control the rotational speed toward a predetermined target value, and controls the rotational shaft torque (drive torque and power generation torque) toward the predetermined target value. Torque control to be performed, and when the flag ODRMG1 is 0, torque control is performed.
[0023]
In S3, a target rotational speed NSET used for controlling the rotational speed of the first motor generator 16 is calculated and commanded. For example, as shown in FIG. 11, the target rotational speed NSET is a value obtained from a table (a) using the accelerator opening APO as a parameter and a value obtained from a table (b) using the output rotational speed OUTREV as a parameter. Choose the smaller one.
[0024]
When the rotational speed RNMG1 of the first motor generator 16 is equal to or higher than a first target value (NSET-M2FNNE) obtained by subtracting a predetermined margin M2FNNE from the target rotational speed NSET, the process proceeds from S4 to S5, and an engine fuel injection command signal is output. Then, the fuel injection of the engine is started (operation mode = 1). Further, when the rotational speed RNMG1 of the first motor generator 16 reaches a second target value (NSET-M1FNNE) obtained by subtracting a predetermined margin M1FNNE from the target rotational speed NSET, it is determined that the engine has completely exploded, and from S6 Proceeding to S7, the operation mode is switched to the idling mode (= 5). However, as shown in FIG. 5, the complete explosion determination margin M1FNNE is smaller than the fuel injection determination margin M2FNNE.
[0025]
Thereafter, in S8, the value (RNMG1 + M13) obtained by adding a predetermined margin M13 to the rotational speed RNMG1 of the first motor generator 16 reaches the output rotational speed OUTREV, and the one-way clutch (61, 62, 63) of the automatic transmission 20 is engaged. When it is determined that the forward drive torque is transmitted from the input shaft 20a to the output shaft 20b of the automatic transmission 20, the process proceeds to S9, and the rotation speed command flag ODRMG1 of the first motor generator 16 is set. Clear to 0 (zero). As a result, the first motor generator 16 is switched from the rotational speed control to the torque control, and the power generation torque of the first motor generator 16 is gradually brought closer to a predetermined power generation request torque (S10).
[0026]
As described above, when the accelerator opening is a relatively low small / medium accelerator opening, the first motor generator 16 is controlled at the rotational speed until the one-way clutch of the automatic transmission 20 is engaged after the completion of the engine explosion. Then, the input rotational speed INPREV of the input shaft 20a of the automatic transmission 20 that rotates in synchronization with the engine 14 and the first motor generator 16 is changed to the output rotational speed OUTREV within a range that does not exceed the output rotational speed OUTREV. And gradually getting closer. For this reason, when the engine torque suddenly increases at the time of the complete explosion of the engine, as indicated by reference numeral 70 in FIG. 5, the torque command value TTMG1 of the first motor generator 16 is a positive value for starting the engine ( The driving torque is immediately switched to a negative value (power generation torque) for absorbing the engine torque. That is, the first motor generator 16 is switched from the drive mode to the power generation mode, and the torque is greatly reduced. As a result, even immediately after the complete explosion when the engine torque suddenly increases, the rapid increase in the input rotational speed INPREV is suppressed, there is no risk that the one-way clutch will be suddenly engaged and a torque shock will occur, and the engine torque will be increased. The amount of power generation is increased by the amount absorbed by one motor generator 16 and the fuel consumption is improved.
[0027]
Further, in the idling state, that is, in a state where the one-way clutch of the automatic transmission 20 is not engaged, the input shaft 20a is substantially in a no-load state, and therefore, between the engine and the motor generator and the automatic transmission. The rotational speed of the first torque generator 19 corresponding to the engine rotational speed is almost equal to the rotational speed RNMG1 of the first motor generator 16 and the input rotational speed INPREV of the automatic transmission. Therefore, when the rotational speed control of the first motor generator 16 is performed in the idling state, the rotational speed RNMG1 of the first motor generator that is also used for other engine control or the like is used as the input rotational speed INPREV of the automatic transmission. Can be used. Therefore, it is not necessary to switch to the rotational speed control by reading the input rotational speed INPREV of the automatic transmission 20, and the control can be simplified.
[0028]
If it is determined in S1 of FIG. 8 that the accelerator opening is not a small / medium opening and the accelerator opening is sufficiently large (operation mode 4) in S11, the high accelerator opening shown in FIGS. Drive control is performed. In S12, the rotation speed command flag ODRMG1 of the first motor generator 16 is set to 1. Thereby, the rotational speed control of the first motor generator 16 is started so that the input rotational speed INPREV gradually increases toward the output rotational speed OUTREV.
[0029]
In S13, the target rotational speed NSET used for the rotational speed control of the first motor generator 16 is set. In S14, an engine fuel injection command is output, and engine fuel injection is started. In other words, under the condition of the high accelerator opening, fuel injection is started immediately regardless of the rotational speed RNMG1 of the first motor generator 16 to improve acceleration.
[0030]
Further, by controlling the rotation speed of the first motor generator 16 until at least after the complete explosion of the engine, as in the case of the small / medium accelerator opening, the first motor generator 16 increases the engine torque immediately after the complete explosion of the engine. Can be offset by the torque reduction (see reference numeral 71 in FIG. 6). Therefore, in addition to the possibility that the one-way clutch is suddenly engaged immediately after the engine complete explosion and there is no risk of sudden torque fluctuations, the amount of power generation is increased by the amount of absorption of the torque at the start of the engine by the first motor generator 16, Fuel consumption is improved.
[0031]
When the rotational speed RNMG1 of the first motor generator 16 reaches a predetermined rotational speed (NSET-M4FNNE), the process proceeds from S15 to S16, the engine is completely exploded, and the absorption of the engine torque increase immediately after the complete explosion is finished. It is determined that the operation mode is switched to the operation mode 10, and the rotation speed command flag ODRMG1 of the first motor generator 16 is cleared to 0 (zero) (S17). Thereby, the first motor generator 16 is switched from the rotational speed control to the torque control, and the power generation torque STMG1 of the first motor generator 16 is gradually brought closer to the predetermined power generation required torque TTMG1 (S18). As described above, when the acceleration demand is high and the accelerator opening is large, the rotational speed control of the first motor generator 16 is canceled immediately after the complete explosion and the torque control is switched to suppress the sudden torque shock immediately after the complete explosion. -While avoiding, it is possible to raise vehicle acceleration rapidly and to improve vehicle acceleration.
[0032]
Thereafter, when the value obtained by adding the predetermined margin M13 to the rotational speed RNMG1 of the first motor generator 16 reaches the output rotational speed OUTREV, the process proceeds from S19 to S20, and at least one of the one-way clutches 61, 62, 63 of the automatic transmission 20 is reached. One is fastened and it is determined that torque has been transmitted from the input shaft 20a to the output shaft 20b of the automatic transmission 20, and the operation mode is switched to the predetermined operation mode 13. In this operation mode 13, torque control is performed on the first motor generator 16 toward a predetermined power generation request torque, and the torque command value TTMG2 of the second motor generator 18 is gradually decreased.
[0033]
7 and 10 show another example of the drive control for the high accelerator opening described above. In this example, the acceleration of the vehicle is emphasized, and the engine is quickly started without performing the rotational speed control of the first motor generator 16. That is, in S21, an engine fuel injection command is output, and engine fuel injection is immediately started. When the rotational speed RNMG1 of the first motor generator 16 reaches a predetermined rotational speed (NSET-M4FNNE), the routine proceeds from S22 to S23, where it is determined that the engine has completely exploded, the operation mode is set to 10, and reference numeral 72 in FIG. As shown, the torque command value TTMG1 of the first motor generator 16 is sharply reduced in order to absorb the torque fluctuation due to the engine starting. Thereafter, when the value obtained by adding the predetermined margin M13 to the rotational speed RNMG1 of the first motor generator 16 reaches the output rotational speed OUTREV, the process proceeds from S24 to S25, and at least one of the one-way clutches 61, 62, 63 of the automatic transmission 20 is increased. One is fastened and it is determined that torque has been transmitted from the input shaft 20a to the output shaft 20b of the automatic transmission 20, and the operation mode is switched to the predetermined operation mode 13. In this operation mode 13, the torque control value TTMG2 of the second motor generator 18 is gradually lowered while controlling the torque of the first motor generator 16 toward a predetermined required power generation torque.
[0034]
Although specific embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and includes various modifications and changes without departing from the spirit of the present invention. For example, the control shown in FIG. 10 is performed when the accelerator opening is higher than a predetermined threshold, and the control shown in FIG. 9 is performed when the accelerator opening is lower than the above threshold. Anyway.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an outline of an electric four-wheel drive vehicle according to an embodiment of the present invention.
2 is a configuration diagram showing a torque converter and an automatic transmission of the vehicle shown in FIG. 1;
3 is an explanatory view showing the operation of a clutch and a brake of the automatic transmission of FIG. 2. FIG.
4 is an explanatory diagram showing the operation of the high and low reverse clutch and the low coast brake of FIG. 3;
FIG. 5 is a timing chart showing a flow of drive control when the small / medium accelerator is opened.
FIG. 6 is a timing chart showing an example of the flow of drive control when the accelerator opening is high.
FIG. 7 is a timing chart showing another example of the flow of drive control when the accelerator opening is high.
FIG. 8 is a flowchart including a flow of drive control when the small / medium accelerator is opened.
FIG. 9 is a part of a flowchart showing an example of a flow of drive control when the accelerator opening is high.
FIG. 10 is a part of a flowchart showing another example of the flow of drive control when the accelerator opening is high.
FIG. 11 is an explanatory diagram showing a setting example of a target rotation speed NSET.
[Explanation of symbols]
10 ... Rear wheel (drive wheel)
12 ... Front wheel (sub drive wheel)
14 ... Engine 16 ... First motor generator (motor generator)
18 ... Second motor generator (sub motor)
DESCRIPTION OF SYMBOLS 19 ... Torque converter 20 ... Automatic transmission 20a ... Input shaft 20b ... Output shaft 61-63 ... One-way clutch INPREV ... Input rotational speed OUTREV ... Output rotational speed

Claims (6)

An automatic transmission including a clutch element, an engine and a motor generator that are linked to the input shaft of the automatic transmission and that can rotate integrally with the input shaft, and drive wheels that are linked to the output shaft of the automatic transmission; In a vehicle control device having
When the engine accelerates from an idling state where the input rotational speed to the automatic transmission is smaller than the rotational speed obtained by multiplying the rotational speed of the output shaft of the automatic transmission by the speed ratio , the input rotational speed is Control the rotational speed of the motor generator so that it does not exceed the rotational speed obtained by multiplying the rotational speed of the output shaft by the gear ratio .
And having a sub motor linked to a sub drive wheel different from the drive wheel,
The vehicle control device according to claim 1, wherein the idling state is a traveling state in which the sub driving wheels are driven by the sub motor. An automatic transmission including a clutch element, an engine and a motor generator that are linked to the input shaft of the automatic transmission and that can rotate integrally with the input shaft, and drive wheels that are linked to the output shaft of the automatic transmission; In a vehicle control device having
When the engine accelerates from an idling state where the input rotational speed to the automatic transmission is smaller than the rotational speed obtained by multiplying the rotational speed of the output shaft of the automatic transmission by the speed ratio , the input rotational speed is Control the rotational speed of the motor generator so that it does not exceed the rotational speed obtained by multiplying the rotational speed of the output shaft by the gear ratio .
And having a sub motor linked to a sub drive wheel different from the drive wheel,
The idling state is a creep running state in which the sub drive wheels are driven by the sub motor,
A vehicle control apparatus characterized in that the engine acceleration time is when the engine is started from an engine stop state.   3. The vehicle control device according to claim 2, wherein when the engine is accelerated from the idling state, the rotational speed of the motor generator is controlled at least until immediately after the complete explosion of the engine. The automatic transmission has a one-way clutch that is fastened when the driving force is transmitted to the driving wheels,
4. The vehicle control device according to claim 2 , wherein the motor generator is controlled at a rotational speed until the one-way clutch is engaged during engine acceleration from the idling state.   The vehicle control device according to claim 4, wherein the motor generator is subjected to torque control after the one-way clutch is engaged. A torque converter interposed between the engine and motor generator and the automatic transmission;
Means for detecting the rotational speed of the motor generator,
The vehicle control device according to any one of claims 2 to 5, wherein when the rotational speed of the motor generator is controlled, the rotational speed of the motor generator is used as the input rotational speed of the automatic transmission. .

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