JP2000069609A - Motor assistance controller for hybrid car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the efficiency of engine assistance higher without spoiling the sensation of acceleration by decreasing the quantity of decided assistance according to the operating condition of a car, by a ratio corresponding to the difference between a detected value of the charged quantity of a capacitor and a threshold set beforehand. SOLUTION: The relation between a capacitor voltage VCAP and each of threshold VCAPLMTL, set beforehand as a lower limit value for compensating the operation of an electrical equipment system and the upper limit value VCAPLMLH of assistance is determined (S32, S33). If VCAP<=VCAPLMLH, a correction factor α is found (S35) by dividing the difference DVCAPLML between VCAP and VCAPLMTL by (VCAPLMTL-VCAPLMLH). An assistance determining flag F.AST is set to 1 (S36, S37), after multiplying the quantity of assistance determined previously by α, and correcting the quantity of assistance in accordance with VCAP If VCAP>VCAPLMLH, F.AST is set to 1, and the motor is driven with ASTPWR. If VCAP<=VCAPLMTL, F.AST is set to zero after setting ASTPWR to 0, and assistance by motor driving is not performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor assist control device for accelerating a hybrid vehicle powered by an engine and a motor for assisting the engine.

[0002]

2. Description of the Related Art Conventionally, in a hybrid vehicle using an engine and a motor for assisting the engine as a power source, when the vehicle is accelerated, the motor is driven by an assist amount determined according to the driving state of the vehicle at that time. In addition to assisting the engine, power is supplied from a power storage device as a power source for driving the motor to the electrical system of the vehicle via a downverter at the time of assisting.

[0003]

The problem to be solved is that, when assisting by motor drive is performed for a long period of time, the amount of charge of a power storage device as a drive power source for the motor can guarantee the operation of the electrical system. If the value falls below the lower limit, the electrical system may malfunction. At this time, a large amount of power can be supplied to the power storage device, but this is a problem when a capacitor such as an electric double layer capacitor having a relatively small charge capacity is used.

At this time, when the charge amount of the power storage device becomes a lower limit value that can guarantee the operation of the electrical system, the assist by the motor drive is stopped or the assist amount is limited to a certain value or less. Not only will the efficiency of the engine assisted by the motor drive become poor,
There is a problem that the acceleration is suddenly changed and riding comfort is impaired.

[0005]

SUMMARY OF THE INVENTION According to the present invention, at the time of acceleration of a vehicle, not only the driving state of the vehicle at that time, but also the optimal assist amount corresponding to the charge amount of the power storage device, without impairing the feeling of acceleration. In order to enable the engine to be efficiently assisted, the ratio is determined in advance according to the driving state of the vehicle with a ratio corresponding to the difference between the detected value of the charge amount of the power storage device and a preset threshold value. Correction means for reducing the assist amount provided is employed.

[0006]

FIG. 1 shows a system configuration of a hybrid vehicle, comprising an engine 1, a motor 2 for assisting an engine, a transmission 3, a power drive unit 4 for driving a motor, and a power storage device 5 as a power supply for driving the motor. The drive system includes a drive system, and a control system including a motor ECU 6 that controls the drive and regeneration of the motor 2 via the power drive unit 4 and an ECU 7 that performs overall control. Power storage device 5 includes a battery or a capacitor. In the figure, reference numeral 8 denotes driving wheels of the vehicle.

[0007] The ECU 7 reads detection signals from various sensors to determine the driving state of the vehicle, and according to the driving state of the vehicle at that time, starts, idle-stop mode, idle mode, acceleration assist mode, cruise control mode. Mode and the deceleration regeneration mode are determined, and an instruction to execute the determined operation mode is given to the motor ECU 6. Then, the motor ECU 6 to which the execution command of the operation mode is given is configured to appropriately control the stop of the motor 2, the assist drive, and the deceleration regeneration via the power drive unit 4.

Further, the downverter 9 is controlled by the ECU 7 so that the voltage of the power storage device 5 is reduced to a predetermined value to charge the battery 10 for the 12V power supply load 11.

FIG. 2 shows a flow of processing in the ECU 7 for setting the operation mode of the motor 2 according to the driving state of the vehicle.

Here, first, it is determined whether or not the starter switch is on (step S1). If it is on, the engine speed Ne detected by the sensor at that time is determined in advance. It is determined whether or not the rotation speed is equal to or less than the rotation speed NCR set for the engine stop determination (step S2). At that time, Ne ≦ NCR
If so, the start mode is set (step S3).

If the starter switch is not turned on at the time of the determination in step S1, the engine stop control execution flag F / FCMG for controlling whether or not to stop the engine during idling is set to 1. Is checked (step S4), the flag FF
If the CMG does not stand, the process proceeds to the determination in step S2.

At this time, the engine stop control execution flag F
-If FCMG stands at 1, the throttle opening TH detected by the sensor is the idle opening (fully closed) THID
It is determined whether or not LE has been set (step S
5).

At the time of determination in step S5, TH ≦ THIDL
If E, then it is determined whether or not the vehicle speed V is 0 (step S6). If V = 0 at that time, it is determined whether or not the engine stop control execution flag F · FCMG is set to 1 (step S7).
If the FCMG is set, the idle mode is set (step S8). If the flag F.FCMG is not set, the idle mode is set (step S9).

If it is determined at step S6 that V = 0 has not been reached, the engine stop control execution flag F.FCMG
Is set to 1 (step S10), and if the flag F.FCMG is set, the deceleration regeneration mode is set (step S12). In addition, the flag FF
If the CMG is not standing, it is determined whether or not the idling control execution flag F · IDLE for instructing the engine to idle is standing at 1 (step S11). At that time, if the flag F.IDLE is set, the idle mode is set (step S9), and the flag F.IDLE is set.
If LE is not set, the deceleration regeneration mode is set (step S12).

Further, at the time of the determination in step S5, TH ≦ TH
If it is not IDLE, a preset assist trigger table is searched to determine whether the vehicle is in an acceleration state or a cruise state (step S13).

FIG. 3 shows the contents of an assist trigger table which is set for each gear position, using the engine speed Ne and the throttle opening TH as parameters and setting the throttle opening as the engine speed Ne decreases. When TH tends to increase, the acceleration mode determination flag F · MAST changes from 0 to 1 when it becomes equal to or higher than the threshold value MASTH set at a higher value, and the throttle opening degree increases as the engine speed Ne increases. When TH tends to decrease, a lower threshold M is set.
When it becomes less than ASTL, the acceleration mode determination flag FM
AST changes from 1 to 0.

Then, the acceleration mode determination flag F.MAS
Check whether T stands at 1 (step S14),
If the flag F.MAST is set, the acceleration assist mode is set (step S15).
If the MAST is not standing, the cruise mode is set (step S16).

When each operation mode of the motor 2 is set as described above, the ECU 7 outputs an execution command of each operation mode to the motor ECU 6 (step S17), and repeats the same processing.

When the assist trigger table shown in FIG. 3 is searched to determine whether the vehicle is in an acceleration state or a cruise state, under the control of the ECU 7,
When the vehicle is in a state of climbing a hill or cruising at a high speed, the cruise determination region is expanded by appropriately raising the MASTH line set higher and the MASTL line set lower, so that the power storage device 5 is regenerated by cruise regeneration. Charging is performed more effectively.

FIG. 4 shows a flow of processing for raising the MASTH line and the MASTL line in the assist trigger table at that time.

In this case, first, the detected slope angle SLP of the vehicle is set to a predetermined threshold value SLPAS for deciding a hill.
It is determined whether or not it is equal to or more than TH (step S2)
1).

At this time, if SLP <SLPASTH, then it is determined whether or not the vehicle speed V is equal to or higher than a high-speed determination threshold value VHWY (step S22). And
If V ≧ VHWY, an absolute value DVAST of a value obtained by subtracting the vehicle speed smoothing calculation result VAVE corresponding to the average vehicle speed from the current vehicle speed V is obtained (step S23), and the value DVA is obtained.
It is determined whether or not ST is less than or equal to a threshold value DVHWY for high-speed maintenance determination (step S24).

The result of the determination in step S21 is SL
When P ≧ SLPASTH or in step S2
When the determination result of 4 is DVAST ≦ DVHWY, the throttle fluctuation amount DTHCA with respect to CAPV is determined in advance.
The DTHCAP table in which the characteristic of P is set is searched, and the throttle fluctuation amount DTHCAP for performing the line raising determination is calculated (step S25).

FIG. 5 shows the characteristics of the DTHCAP table.

Next, the current throttle opening change amount D
It is determined whether or not TH is smaller than the throttle fluctuation amount DTHCAP (step S26).
If DTHCAP, the previous line raising amount DTH
AST (n-1) is incremented by a predetermined line by increasing DDT.
HAST is added, and this line raising amount DTHAS
Tn is calculated (step S27).

Next, the calculated line raising amount D
It is determined whether or not THAST is equal to or more than the upper limit value DTHLMT of the throttle fluctuation amount for performing the line raising determination (step S28).

At this time, if DTHAST ≧ DTHLMT, the calculated line raising amount DTHAST is replaced with the upper limit value DTHLMT (step S29),
The assist trigger table is searched while the line is raised by the upper limit DTHLMT (step S
210).

At that time, DTHAST <DTHLM
If T, the assist trigger table is searched in a state where the line is raised by the calculated line raising amount DTHAST (step S210).

If the result of the determination in step S22 is V <VHWY
Or when the determination result of step S24 is DV
If AST> DVHWY, a predetermined line raising amount DDTHAST is subtracted from the previous line raising amount DTHAST (n-1) to calculate the current line raising amount DTHASTn (step S21).
1).

Then, it is determined whether or not the calculated line raising amount DTHAST is equal to or less than 0 (step S).
212), if DTHAST ≦ 0, the line raising amount DTHAST is set to 0 (step S21).
3), the assist trigger table is searched (step S210).

At the time of determination in step S26, DTH ≧ DT
Similarly, in the case of HCAP, the line raising amount DT
After setting HAST to 0 (step S213), the assist trigger table is searched (step S21).
0).

At the time of determination in step S212, DT
If HAST> 0, the assist trigger table is searched based on the line raising amount DTHAST calculated at that time (step S210).

Hereinafter, the same processing is repeated at a predetermined control cycle (for example, 10 ms).

Under the control of the ECU 7, in the acceleration assist mode, a charge request from the 12V power supply battery 10 via the downverter 9 is supplied from the power storage device 5 and in the deceleration regeneration mode from the motor 2. Similarly, power is supplied from the motor 2 during cruise generation in the cruise mode, and from the power storage device 5 during cruise assist. The power is supplied from the motor 2 in the idle mode, and is supplied from the power storage device 5 in the idle stop mode.

In the motor assist control apparatus for a hybrid vehicle configured as described above, in particular, in the present invention,
Under the control of the ECU 7, in the acceleration assist mode,
When driving the motor 2 with the assist amount determined according to the driving state of the vehicle, the charge amount of the power storage device 5 is detected, and the detected value is set as a lower limit value that guarantees the operation of the electrical system. The previously determined assist amount is appropriately reduced at a rate corresponding to the difference from the threshold value.

FIG. 6 shows a flow of a process for determining the assist amount according to the driving state of the vehicle in the acceleration assist mode and correcting the determined assist amount according to the charge amount of the power storage device 5 at that time. ing.

Here, first, an ASTPWR map is searched to find an assist amount ASTPW according to the driving state of the vehicle.
R is determined (step S31).

Table 1 shows that the transmission 3 is controlled by the manual transmission M using the rotation speed of the engine 1 and the throttle opening as parameters.
9 shows an ASTPWR map set for each gear position in the case of T or a stepped automatic transmission AT.

Here, the engine speed is set to NEAST0.
NEAST19 to 20 levels, and the throttle opening is divided into 11 levels THAST0 to THAST10. For example, when the detected engine speed is at the NEAST1 level and the throttle opening is at the THAST1 level, the assist amount is determined as ASTPWR # n11.

[0040]

[Table 1]

Similarly, when the transmission 3 is a continuously variable automatic transmission CVT, an ASTPWR map in which the engine speed and the vehicle speed are set as parameters is prepared.

Next, it is determined whether or not the capacitor voltage VCAP detected by the power storage device 5 is larger than a threshold value VCAPLMTL previously set as a lower limit value for guaranteeing the operation of the electrical system (step S32). At that time, VCA
If P> VCAPLMTL, it is determined whether or not the capacitor voltage VCAP at that time is equal to or less than a threshold value VCAPLMLH set as a preset upper limit value of the assist amount correction (step S33).

At this time, if VCAP ≦ VCAPLMLH, a difference DVCAPLML between the capacitor voltage VCAP and the lower limit threshold value VCAPLMTL is obtained (step S34). And the difference DVCAPLM
Let L be the lower limit VCAPLMLH and the upper limit VCAPLMT
The correction coefficient α is obtained by dividing by the difference from L (step S35).

The assist amount is corrected in accordance with the capacitor voltage VCAP by multiplying the obtained correction coefficient α by the previously determined assist amount ASTPWR (step S36). Set AST to 1 (step S37).

At the time of determination in step S33, VCAP> V
In the case of CAPLMLH, the previously determined assist amount A
In order to drive the motor with STPWR, the assist amount determination flag F · AST is set to 1 (step S3
7).

At the time of determination in step S32, the VCA
If P ≦ VCAPLMTL, the previously determined assist amount ASTPWR is set to 0 (step S3).
8) The assist amount determination flag F · AST is set to 0 (step S39), so that assist by motor drive is not performed.

As described above, according to the present invention, power storage device 5
When the capacitor voltage VCAP is equal to or lower than the lower limit value VCAPLMTL that guarantees the operation of the electrical system, assist by motor drive is not performed.

When the capacitor voltage VCAP is higher than the upper limit value VCAPLMLH of the assist correction,
Assuming that the charge amount of the power storage device 5 is sufficient, the motor-driven assist of the engine 1 is efficiently performed with the assist amount uniformly determined according to the driving state of the vehicle.

When the capacitor voltage VCAP is higher than the lower limit value VCAPLMTL and is equal to or lower than the upper limit value VCAPLMLH for assist correction, a predetermined ratio corresponding to the difference DVCAPLML between the capacitor voltage VCAP at that time and the lower limit value VCAPLMTL is used. The assist amount uniformly determined according to the driving state of the vehicle is corrected so as to decrease, and the motor is driven with the corrected assist amount. Therefore, capacitor voltage VCAP of power storage device 5 has lower limit value VC that guarantees the operation of the electrical system.
As the value approaches APLMTL, the assist amount gradually decreases at a predetermined rate, and the malfunction of the electrical system due to the decrease in the charge amount of the power storage device 5 due to excessive motor drive is effectively prevented. At the same time, the assist amount is corrected so that the assist amount gradually decreases at a predetermined rate, so that the sudden change in acceleration does not impair ride comfort.

[0050]

As described above, according to the present invention, when accelerating a hybrid vehicle powered by an engine and a motor for assisting the engine, a motor drive is performed with an assist amount determined according to the driving state of the vehicle at that time. In the motor assist control device for a hybrid vehicle, the power storage device as a power source for driving the motor is supplied to the electric system of the vehicle via a downverter at the time of assisting. Correction means for reducing the assist amount previously determined according to the driving state of the vehicle at a rate corresponding to the difference between the detected value and a preset threshold value is used. In addition, with the optimal assist amount that matches the charge amount of the power storage device, the engine can be stopped without losing the feeling of acceleration. It has the advantage of being able to rate well performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of a system configuration of a hybrid vehicle according to the present invention.

FIG. 2 is a diagram illustrating a flow of a process for setting a motor operation mode according to a driving state of a vehicle.

FIG. 3 is a characteristic diagram showing contents of an assist trigger table set for each gear position.

FIG. 4 is an upper limit MAS in an assist trigger table.
It is a figure which shows the flow of a process which raises a TH line and a lower MASTL line.

FIG. 5 is a characteristic diagram showing the contents of a DTHCAP table.

FIG. 6 is a diagram illustrating a flow of a process of correcting an assist amount determined according to a driving state of a vehicle in accordance with a charge amount of a power storage device in an acceleration assist mode.

[Explanation of symbols]

 Reference Signs List 1 engine 2 motor for engine assist 3 transmission 4 power drive unit 5 power storage device 6 motor ECU 7 ECU 9 downverter 10 battery for 12V power supply

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02P 9/04 H02P 9/04 L (72) Inventor Atsushi Matsubara 1-4-1 Chuo, Wako-shi, Saitama Inside Honda R & D Co., Ltd. (72) Inventor Atsushi Izuura 1-4-1 Chuo, Wako-shi, Saitama Prefecture Inside Honda R & D Co., Ltd. (72) Keisuke Uchida 1-4-1 Chuo, Wako-shi, Saitama Pref. No. Within Honda R & D Co., Ltd. (72) Inventor Fumihiko Konno 1-4-1 Chuo, Wako-shi, Saitama F-term within R & D Co., Ltd. F-term (reference) 3G084 AA00 BA00 CA04 DA11 DA15 EA11 EB08 EB12 FA03 FA05 FA10 FA33 3G093 AA05 AA07 BA02 BA15 CB06 DA01 DA06 DB05 EC02 FA04 FA08 FA10 FB03 5G003 BA02 CC02 DA02 DA13 FA06 FA08 GB03 GC05 5H115 PA01 PC06 PG04 PI11 PI16 PI22 PI29 PO02 PO17 PU01 PU23 PU25 PV02 PV09 QN03 QN27 RB08 SE04 TB01 TE02 TE03 TI01 TO07 TR19 TU06 TZ04 TZ11 5H590 AA30 AB20 CA07 CA16 CA23 CD03 CE05 FA08 HA02 HA11 HA24 HA27 JA02

Claims (2)

[Claims] When a hybrid vehicle powered by an engine and a motor for assisting the engine is accelerated, the engine is assisted by driving the motor with an assist amount determined according to a driving state of the vehicle at that time. Sometimes, in a motor assist control device for a hybrid vehicle configured to supply power from a power storage device serving as a power source for driving the motor to an electrical system of the vehicle via a downverter, a means for detecting a charge amount of the power storage device, Motor assist control for a hybrid vehicle, wherein the assist means reduces the assist amount previously determined at a rate corresponding to a difference between the charged amount of the power storage device and a preset threshold value. apparatus. 2. The motor assist control device for a hybrid vehicle according to claim 1, wherein the threshold value is a lower limit value of a charge amount in the power storage device.