DE102019117773A1 - Hybrid vehicle - Google Patents

Abstract

[Problem to be Solved] In a hybrid vehicle, an actual drive torque depending on a request from a driver can be efficiently obtained, while the slipping of a belt can be prevented efficiently and the deterioration of drivability can be prevented efficiently. [Solution] The present Invention relates to a hybrid vehicle comprising: an engine 1; and a motor 2 that can support the rotation of the engine 1 via a belt 3. The hybrid vehicle includes: a drive control unit 31 that can switch an operation mode between an engine drive mode and an engine drive mode; and a torque setting unit 32 configured to set a limit torque E, the limit torque E being a threshold value for limiting a torque output from the engine 2 to prevent the belt 3 from slipping. The drive control unit 31 changes the mode to the engine drive mode and prevents the change to the motor drive mode when the request drive torque T is greater than the limit torque E during the motor drive mode.

Description

[Technical field]

The present invention relates to hybrid vehicles that include an engine and an engine configured to be able to transmit rotation to the engine through the mediation of a belt.

[Technical background]

A hybrid vehicle, such as B. a hybrid motor vehicle, includes an engine and a motor used for driving and driving, and can transmit the power of the engine to the engine by providing a belt so that it can assist the rotation of the engine. However, when a request torque increases due to an acceleration request or the like in a state in which the vehicle is running at only the power of the engine, a load on the engine increases, and typically a load on the belt also increases. If a state in which the load on the belt increases continues, the belt may slip and the belt may continue to deteriorate.

Accordingly, various techniques for preventing the belt from slipping (hereinafter referred to as a "belt slip prevention technique") have been proposed. As an example of the belt slip prevention technique, there is a technique for limiting a load torque of a power generator of an internal combustion engine such as an engine. B. an engine or the like, to such a value that the belt can not slip. In this example of the belt slip prevention technique, when the load torque of the power generator is limited, an output deficiency of the power generator generated due to this limitation of the load torque is calculated, and further the speed of the power generator is increased depending on the output deficiency. (See e.g. Patent Literature 1.)

[List of references]

[Patent literature]

[Patent Literature 1] JP 2006-027598 A

SUMMARY OF THE INVENTION

[Technical problem]

However, in a case where the above-mentioned example of the belt slip prevention technique is applied to the belt of the hybrid vehicle for transmitting the power of the engine to the engine and a torque of the engine is limited to prevent the belt from slipping, an actual drive torque can be of the hybrid vehicle depending on a request from a driver, e.g. B. A driver request torque cannot be obtained during a motor drive mode of driving by driving the motor in a state in which the drive of the engine is stopped, in other words, during a so-called electric vehicle mode (EV mode).

Regarding the hybrid vehicle that changes the mode between the above-mentioned motor drive mode and the engine drive mode of driving by driving the engine, it is in a case where, as in the above-mentioned example of the belt slip prevention technique, the speed of the motor is dependent on the output shortfall of the Engine is significantly increased in view of the state of the belt, switching between the motor drive mode and the engine drive mode and / or the like, it is difficult to set a state of compensating the output shortage of the motor efficiently while preventing the belt from slipping. As a result, a feeling of acceleration of the hybrid vehicle can be lost and a driver can feel a feeling of inconvenience about the operation. That is, driveability may deteriorate.

In view of such circumstances, in the hybrid vehicle, it is desirable to obtain an actual drive torque depending on a request from a driver while efficiently preventing the belt from slipping, and it is desirable to efficiently prevent drivability from deteriorating. Incidentally, in the hybrid vehicle, it is desirable to prevent the belt from deteriorating.

[Solution to the problem]

To solve the problems described above, according to one aspect, a hybrid vehicle includes: an engine; an engine configured to assist rotation of the engine by providing a belt; a drive control unit configured to control the driving of the engine and the driving of the engine to determine a mode between a motor driving mode of driving by driving the motor in a state in which the driving of the engine is stopped and an engine driving mode of the To change driving by driving the engine; and a torque setting unit configured to set a limit torque, the limit torque being a threshold for limiting a torque output from the engine to prevent the belt from slipping, the drive control unit configured to change the mode to the engine drive mode to restart the engine and to prevent switching to the motor drive mode when the request drive torque is greater than the limit torque during the motor drive mode.

Advantageous Effects of Invention

In the hybrid vehicle according to one aspect of the invention, the actual drive torque depending on a request from a driver can be efficiently obtained while efficiently preventing the slippage of the belt and deterioration of drivability can be prevented efficiently. Incidentally, deterioration of the belt can be prevented in the hybrid vehicle.

Figure list

• 1 FIG. 12 is a configuration diagram schematically showing a drive mechanism of a hybrid vehicle according to the present embodiment.
• 2 FIG. 12 is a configuration diagram that schematically shows a hybrid ECU, an engine ECU, and an engine ECU of the hybrid vehicle according to the present embodiment.
• 3 FIG. 10 is an example of a map used for setting a limit torque and a permission torque in the hybrid vehicle according to the present embodiment.
• 4 FIG. 11 is a flowchart showing an example of drive control of the hybrid vehicle according to the present embodiment.

DESCRIPTION OF EMBODIMENTS

A hybrid vehicle according to the present embodiment will be described. It is stated that it is preferred that the hybrid vehicle is a hybrid motor vehicle. However, the hybrid vehicle may be a vehicle other than a hybrid motor vehicle. B. can be a hybrid motorcycle. Furthermore, the term “motor” is defined in the present application in such a way that it includes an electric motor and a motor generator.

Overview of the hybrid vehicle

An overview of the hybrid vehicle is first described. As in 1 is shown, the hybrid vehicle includes an engine 1 used for driving and driving. The hybrid vehicle also includes a motor generator 2 configured as a motor used for driving and driving. The hybrid vehicle also includes a belt 3 that the rotation of the motor generator 2 for the rotation of the engine 1 transmits. The motor generator 2 can the rotation of the engine 1 through the mediation of the belt 3 support. That is, a hybrid system of the hybrid vehicle according to the present embodiment is a so-called ISG hybrid system (hybrid system with integrated starter generator) of the belt drive type.

In the present embodiment, a case where the motor generator is described will be described here 2 its rotation to the engine 1 transmits. The motor generator 2 can also be caused by the rotation of the engine 1 to the motor generator 2 is transmitted, generate power. However, the engine of the hybrid vehicle can be different from a motor generator. The engine of the hybrid vehicle can e.g. B. can also be an electric motor.

The hybrid vehicle includes a hybrid ECU (hybrid electronic control unit) 21, which is a hybrid control device configured to the engine 1 and the motor generator 2 to be able to control. Note that the hybrid control device may be different from the hybrid ECU.

As in 2 contains the hybrid ECU 21 a drive control unit 31 that is configured to drive the engine 1 and driving the motor generator 2 to be able to control. The drive control unit 31 is configured to operate between: a motor drive mode of driving by driving the motor generator 2 in a state where driving the engine 1 is stopped; and an engine drive mode of driving by driving the engine 1 to be able to switch. The hybrid vehicle can only operate in the engine drive mode by driving the engine 1 drive and can by driving the engine 1 and driving the motor generator 2 which is the rotation of the engine 1 supports, drive. Furthermore, the hybrid vehicle can only operate in the motor drive mode by driving the motor generator 2 drive. The hybrid ECU 21 also includes a torque setting unit 32 configured to set a limit torque E (Nm), the limit torque E being a threshold value for limiting a torque output from the motor generator 2 is around the slippage of the belt 3 to be able to prevent.

In the hybrid ECU 21 is the drive control unit 31 configured to switch the mode to the engine drive mode to drive the engine 1 to restart, and to prevent switching to the motor drive mode when a request drive torque T (Nm) is larger than the limiting torque E caused by the torque setting unit 32 while the motor drive mode is being set. The request drive torque T is an amount of torque that is requested depending on an acceleration request, a deceleration request, a desired vehicle speed of a driver, and / or the like, to the engine 1 and / or the motor generator 2 to be spent. The request drive torque T is a so-called driver request torque. The details of a calculation method for the request drive torque T will be described later.

It is further preferred that the hybrid vehicle according to the present embodiment is configured as follows. As in 3 is the torque setting unit 32 configured to set the limit torque E so that it becomes smaller when a calculated value R (%) of the slip ratio of the belt 3 increases. It is stated that the details of the calculated value R of the slip ratio will be described later.

In addition, the torque setting unit 32 configured to allow torque F (N · m), where the allowable torque F is a threshold value that the output of a torque from the motor generator 2 allowed. The permit torque F is less than the limit torque E , Furthermore, the drive control unit 31 configured to allow switching to the motor drive mode when the request drive torque T less than the allowable torque during the motor drive mode F is. In particular, it is preferred that the drive control unit 31 is configured to allow switching to the motor drive mode when the request drive torque T in a state where switching to the motor drive mode is prevented from being smaller than the permission torque F is.

The torque setting unit 32 is configured to limit torque E and allow torque F set so that they become smaller when a captured value ω1 ( rpm ) the speed of the engine 1 (hereinafter referred to as "engine speed" if necessary) increases. Furthermore, the torque setting unit 32 configured so that a difference between the limiting torque E and the allowance torque F based on the same calculated value R the belt slip ratio 3 be set to become larger as the engine speed increases.

Details of the hybrid vehicle

The details of the hybrid vehicle are described. That is, the hybrid vehicle may further be configured as follows. As in 1 shown includes the engine 1 : an engine main body 1a which is a power source for driving the engine 1 having; and first and second engine rotating shafts 1b . 1c that can rotate. The first and second engine rotating shafts 1b . 1c are with the engine main body 1a connected. The first and second engine rotating shafts 1b . 1c can also by driving the engine 1 rotate and can by the motor generator 2 Rotate transferred rotation. The rotations of the first and second engine rotating shafts 1b . 1c are synchronized with each other. The engine 1 also includes an engine pulley 1d working on the second engine rotating shaft 1c is appropriate. The engine pulley 1d is designed so that the strap 3 around the engine pulley 1d can be excited.

The motor generator 2 contains: an engine generator main body 2a , which is a power source for driving the motor generator 2 having; and a motor rotating shaft 2 B that can rotate. The motor rotating shaft 2 B is with the engine main body 2a connected. The motor rotating shaft 2 B can by driving the motor generator 2 rotate and can by by the engine 1 Rotate transferred rotation. The motor generator 2 also includes a motor pulley 2c working on the engine rotating shaft 2 B is appropriate. The motor pulley 2c is designed so that the strap 3 around the motor pulley 2c can be excited.

The strap 3 has a pulling force so that the belt 3 around the engine pulley 1d and the motor pulley 2c is tensioned to create a friction between each of the engine pulley 1d and the motor pulley 2c and the strap 3 to create. If the motor pulley 2c is rotated in a state in which the belt 3 around the engine pulley 1d and the motor pulley 2c the belt moves 3 along a circumferential direction of the pulleys, the engine pulley 1d by the movement of the belt 3 is rotated in the circumferential direction.

The hybrid vehicle further includes a pair of running drive wheels 4 which are arranged separately from each other in the vehicle width direction. The hybrid vehicle contains the wheel shafts 5 , each along a rotating shaft of the impeller 4 from this running drive wheel 4 extends toward the center in the vehicle width direction. The end portions on the center side in the vehicle width direction of the pair of wheel shafts 5 are with a differential gear 6 connected. The differential gear 6 is configured to determine a rotation difference between the pair of running drive wheels 4 to be able to provide.

The hybrid vehicle contains a transmission 7 configured to be able to change its reduction ratio. The hybrid vehicle also includes a clutch 8th that with the first engine rotating shaft 1b the engine 1 and the transmission 7 connected is. The coupling 8th is configured to change its state between a state in which it is to allow power transmission from the engine 1 to the gearbox 7 indented, and a state in which it is disconnected to interrupt the power transmission. The gear 7 is with the differential gear 6 connected, so it's the power from the engine 1 in a state where the clutch 8th with the gear 7 is connected to the differential gear 6 can transmit. The differential gear 6 is configured to power the transmission 7 to the running drive wheels 8th through the mediation of the wheel shafts 5 to be able to transfer to the running drive wheels 4 spinning.

The hybrid vehicle also contains a starter 9 that is configured to run the engine 1 can start. The hybrid vehicle contains two batteries 10 . 11 , ie, a first and a second battery 10 . 11 , It is preferred that the rated voltage of the second battery 11 greater than the nominal voltage of the first battery 10 is. In particular, it is preferred that the nominal voltage of the first battery 10 is about 12V, that is, it is preferred that the first battery 10 is a 12 V battery (12 V battery). It is further preferred that the first battery 10 is a 12 V lead battery. In particular, it is preferred that the nominal voltage of the second battery 11 is about 48 V, that is, it is preferred that the second battery 11 is a 48 V battery. It is further preferred that the second battery 11 is a 48 V lithium ion battery. The first battery 10 is with the starter 9 electrically connected. The second battery 11 is with the motor generator 2 electrically connected.

The hybrid vehicle contains a DC-DC converter 12 that is electric with the first and second battery 10 . 11 connected is. The DC-DC converter 10 is configured to draw a voltage from the first battery 10 to the second battery 11 to increase, and is configured to a voltage from the second battery 11 to the first battery 10 to be able to reduce. The hybrid vehicle contains an electrical component 13 , such as B. an audio device, air conditioning, various lights and / or the like. The electrical component 13 is with the first battery 10 and the DC-DC converter 12 electrically connected.

The hybrid vehicle also includes an engine ECU 22 that is an engine control device configured to control the state of the engine 1 monitor, and which is configured, the engine 1 to be able to control. The engine ECU 22 is with the engine 1 , the starter 9 and the hybrid ECU 21 electrically connected. The hybrid ECU 21 is configured to store information such as B. the state of the engine 1 from the engine ECU 22 and / or the like, and is configured to give an instruction regarding a driving state of the engine 1 and / or the like to the engine ECU 22 to be able to send.

The hybrid vehicle contains an engine ECU 23 , which is an engine control device configured to control the state of the engine generator 2 monitor, and which is configured, the motor generator 2 to be able to control. The engine-ECU 23 is with the motor generator 2 and the hybrid ECU 21 electrically connected. The hybrid ECU 21 is further configured to receive information such as. B. the state of the motor generator 2 from the engine-ECU 23 and / or the like, and is configured to give an instruction regarding a driving state of the motor generator 2 and / or the like to the engine ECU 23 to be able to send.

The hybrid vehicle also includes a battery ECU 24 , which is a battery monitor configured to monitor the states of the first and second batteries 10 . 11 to be able to monitor. In other words, the battery ECU 24 is configured to input into and output from the first and second batteries 10 . 11 to be able to monitor. The battery ECU 24 is with the first and the second battery 10 . 11 , the hybrid ECU 21 and the engine-ECU 23 electrically connected. It is preferred that the hybrid ECU 21 and the engine-ECU 23 are configured to the motor generator 2 to be able to control the input and output of the first and second batteries 10 . 11 based on the information about the states of the first and second batteries 10 . 11 adjust by the battery-ECU 24 be preserved.

Note that it is preferable that each of the hybrid ECU 21 , the engine ECU 22 , the engine-ECU 23 and the battery ECU contains: an electrical component / electrical components, such as. B. a CPU (central processing unit), a RAM (read-write memory), a ROM (read-only memory), a flash memory, an input interface and / or an output interface; and an electrical circuit in which this electrical component / these electrical components is / are arranged. It is further preferred that the ROM has a program for operating the ECUs stored therein 21 to 24 including the ROM. It is further preferred that the ROM has different constant numbers, different maps and / or the like stored therein, which are used for different calculations and / or the like.

Details of the hybrid ECU

There will be the details of the hybrid ECU 21 further described. As in 2 contains the hybrid ECU 21 an engine speed detection unit 33 configured to sense engine speed. In the hybrid ECU 21 becomes a recorded value ω1 the engine speed by the engine speed detection unit 33 receive. In particular, it is preferred that the engine speed detection unit 33 an engine speed from the engine 1 via the engine ECU 22 can capture.

The hybrid ECU 21 contains an engine speed detection unit 34 that is configured, a speed of the motor generator 2 (which will be referred to as "engine speed" below if necessary). In the hybrid ECU 21 becomes a recorded value ω2 (rpm) of the engine speed by the engine speed detection unit 34 receive. In particular, it is preferred that the engine speed detection unit 34 an engine speed from the engine 2 via the engine-ECU 23 detected.

In this case, the belt can be in the hybrid vehicle 3 in some cases on at least one of the engine pulley 1d and the motor pulley 2c slip. That is why the hybrid ECU contains 21 a slip ratio calculation unit 35 that is configured a slip ratio of the belt 3 based on the captured value ω1 the engine speed and the detected value ω2 to calculate the engine speed. It is stated that the speed of the engine 1 the speeds of the first and second rotating shafts 1b . 1c equivalent. Furthermore, the speeds of the first and the second rotating shaft 1b . 1c essentially the same. The speed of the motor generator 2 corresponds to a speed of the second engine rotating shaft 1c ,

In the hybrid ECU 21 becomes the calculated value R (%) of the slip ratio by the slip ratio calculation unit 35 receive. The calculated value R (%) of the slip ratio can be determined by the (Formula 1) below based on the detected value ω1 the engine speed and the detected value ω2 the engine speed can be obtained.

$$\text{R}=\left(\left|\mathrm{\omega }2-\mathrm{<figure-callout\; id="1"\; label="\omega "\; filenames="DE102019117773A1\_0002.png,DE102019117773A1\_0005.png"\; state="\{\{state\}\}">\omega </figure-callout>}1\right|/\mathrm{\omega }2\right)\times 100$$

As in 3 The limiting and permitting torques are shown by way of example E . F in the torque setting unit 32 is calculated using a map (hereinafter referred to as a "torque setting map") based on a relationship between the calculated value R the slip ratio, the recorded value ω1 the engine speed and the limiting and permitting torques E . F is determined. It is preferable that the torque setting map in the ROM in the hybrid ECU 21 is saved. However, the torque setting map may also be stored in parts other than the ROM in the hybrid ECU.

Is specific in the torque setting map in 3 the horizontal axis is set to the captured value ω1 the engine speed, while the vertical axis is set, around each of the limiting and permitting torques E . F specify. There are also several limiting torque definition lines M1 . M2 . M3 , ... (each indicated by the solid lines), each of which has a relationship between the detected value ω1 engine speed and limit torque E defined, set so that they have multiple calculated values R1 . R2 . R3 , ... correspond to a slip ratio. There are several allowance torque setting lines N1 . N2 . N3 , ... (each indicated by the broken lines), each of which has a relationship between the detected value ω1 the engine speed and the permission torque F defined, set so that they have multiple calculated values R1 . R2 . R3 , ... correspond to a slip ratio. The limiting and permitting torques can be found in the torque setting map E . F depending on the slip ratio R and the recorded value ω1 engine speed can be obtained.

At the same recorded value ω1 the engine speed are the limiting torques E of the multiple limit torque defining lines M1 . M2 . M3 , ... set so that they decrease each time the calculated values R1 . R2 . R3 , ... increase the slip ratio. At the same recorded value ω1 the engine speed are the limiting torques E of the multiple allowance torque specification lines N1 . N2 . N3 , ... also set so that they decrease each time the calculated values R1 . R2 . R3 , ... increase the slip ratio.

The limiting torques E the limit torque specification lines M1 . M2 . M3 , ... are set so that they decrease each time the recorded value ω1 the engine speed increases. The permit torques F each of the allow torque setting lines N1 . N2 . N3 , ... are also set so that they decrease each time the recorded value ω1 the engine speed increases.

Regarding the limit torque specification lines M1 . M2 . M3 , ... and the allowance torque specification lines N1 . N2 . N3 , ... that have the same calculated values R1 . R2 . R3 , ... of the slip ratio are at the same recorded value ω1 of the engine speed, the limiting torques E of the limiting torque setting lines M1 . M2 . M3 , ... are set so that they are greater than the limiting torque of the permissible torque specification lines N1 . N2 . N3 , ... are. Furthermore, with regard to the limit torque definition lines M1 . M2 . M3 , ... and the allowance torque specification lines N1 . N2 . N3 , ... that have the same calculated values R1 . R2 . R3 , ... of the slip ratio, a difference between the limiting torque E each of the limit torque specification lines M1 . M2 . M3 , ... and the permission torque F each of the allow torque setting lines N1 . N2 . N3 , ... at the same recorded value ω1 of the engine speed is set to increase as the detected value ω1 of the engine speed increases.

Note that in the torque setting map in 3 as an example the first limit torque specification line M1 and the first allowance torque specification line N1 are set depending on a case in which the calculated value R1 of the first slip ratio is about 0%, the second limit torque setting line M2 and the second allowance torque setting line N2 are set depending on a case in which the calculated value R2 of the second slip ratio is about 1%, and the third limit torque setting line M3 and the third allowance torque setting line N3 are set depending on a case in which the calculated value R3 the third slip ratio is about 2%.

The hybrid ECU also contains 21 an accelerator pedal position detection unit 36 configured to detect an accelerator pedal position. In the hybrid ECU 21 becomes a recorded value A (%) of an accelerator pedal position by the accelerator pedal position detection unit 36 receive. In particular, it is preferred that the accelerator pedal position detection unit 36 an accelerator pedal position from the engine 1 via the engine ECU 22 detected.

The hybrid ECU 21 includes a vehicle speed detection unit 37 that is configured to be able to detect a vehicle speed. In the hybrid ECU 21 becomes a recorded value V (km / h) of a vehicle speed by the vehicle speed detection unit 37 receive. It is preferable that the vehicle speed detection unit 37 a vehicle speed is detected by a vehicle speed sensor (not shown) or the like of the hybrid vehicle.

The hybrid ECU 21 includes a request drive torque calculation unit 38 configured to be a request drive torque T based on a captured value A an accelerator pedal position and a detected value V to calculate a vehicle speed. In particular, it is preferred that the request drive torque T is calculated using a map (hereinafter referred to as a “request drive torque map” if necessary), which is a relationship between the request drive torque T and the detected value A of the accelerator pedal position and the detected value V the vehicle speed defined. It is preferable that the request drive torque map in the ROM of the hybrid ECU 21 is saved. However, the request drive torque map may also be stored in parts other than the ROM in the hybrid ECU.

Furthermore, the request drive torque T based on one for the engine 1 requested engine request drive torque T1 (Nm) and one for the motor generator 2 requested engine request drive torque T2 (Nm) defined. If the hybrid vehicle z. B. is set in the engine drive mode, the engine request drive torque T1 be set so that it is substantially equal to the request drive torque T is.

If the hybrid vehicle z. B. is set in the motor drive mode, the motor request drive torque T2 essentially equal to the request drive torque T be set. It is stated that the total value of the Engine request drive torque T1 and the engine demand drive torque T2 depending on a state of the hybrid vehicle can be set so that it is substantially equal to the request drive torque T is. It is Z. For example, it is preferred that when the hybrid vehicle is in the middle of switching to the engine drive mode and the motor drive mode, the engine request drive torque T1 and the engine request drive torque T2 be increased or decreased to maintain the state in which the total engine demand drive torque T1 and the engine demand drive torque T2 is set so that it is substantially equal to the request drive torque T is.

In the hybrid ECU 21 it is preferred that the drive control unit 31 an engine drive execution instruction unit 31a contains that is configured the engine 1 and the engine 2 via the engine ECU 22 and the engine-ECU 23 to instruct to execute the engine drive mode. It is preferred that the drive control unit 31 a motor drive execution instruction unit 31b contains that is configured the engine 1 and the motor generator 2 via the engine ECU 22 and the engine-ECU 23 to instruct to run the motor drive mode.

The drive control unit 31 includes an engine drive change determination unit 31c configured to determine whether the request drive torque T greater than the limit torque E when the hybrid vehicle is in the motor drive mode. The drive control unit 31 includes an engine drive change instruction unit 31d configured to be the engine drive execution instruction unit 31a and the motor drive execution instruction unit 31b instruct to change the motor drive mode to the engine drive mode when in the engine drive change determination unit 31c it is determined that the request drive torque T greater than the limit torque E is. The drive control unit 31 also includes a motor drive change prevention unit 31 e, which is configured, the engine drive execution instruction unit 31a and the motor drive execution instruction unit 31b to instruct to prevent the change from the engine drive mode to the motor drive mode when in the engine drive change determination unit 31c it is determined that the request drive torque T greater than the limit torque E is.

The drive control unit 31 includes a motor drive change determination unit 31f configured to determine whether the request drive torque T greater than the allowable torque F when the hybrid vehicle is in the motor drive mode. In particular, it is preferred that the motor drive change determination unit 31f is configured to determine whether the request drive torque T less than the allowable torque F is when the hybrid vehicle is in the engine drive mode and the change from the engine drive mode to the engine drive mode by the engine drive change prevention unit 31e is prevented. The drive control unit 31 contains a motor drive change permission unit 31g configured to allow switching from the engine drive mode to the motor drive mode when in the motor drive change determination unit 31f it is determined that the request drive torque T less than the allowable torque F is. In particular, it is preferred that the motor drive change permission unit 31g is configured to remove the prevention of switching to the motor drive mode when the request drive torque T in a state in which switching to the motor drive mode is prevented is smaller than the permission torque F.

The drive control unit 31 also includes a motor drive change instruction unit 31h configured to be the engine drive execution instruction unit 31a and the motor drive execution instruction unit 31b instruct to change the engine drive mode to the motor drive mode when in the motor drive change determination unit 31f it is determined that the request torque T less than the allowable torque F is.

It is further preferred that the torque setting unit 32 a limit torque setting unit 32a configured to set the limit torque E as described above and a permission torque setting unit 32b that is configured to allow torque F as described above contains.

Method for controlling the hybrid vehicle

A method for controlling the hybrid vehicle according to the present embodiment will be described below. First, the hybrid vehicle is in the motor drive mode (step S1 ). It is determined whether the request drive torque T greater than the limit torque E is (step S2 ). When the request drive torque T equal to or less than the limit torque E is (no), the hybrid vehicle continues the motor drive mode (step S1 ). When the request drive torque T greater than the limit torque E is (yes), the hybrid vehicle changes the motor drive mode to the engine drive mode (step S3 ). Furthermore, the switch from the engine drive mode to the motor drive mode is prevented (step S4 ).

It is determined whether or not the request drive torque T less than the allowable torque F is (step S5 ). When the request drive torque T equal to or greater than the allowable torque F is (no), the hybrid vehicle continues the engine drive mode (step S3 ). When the request drive torque T less than the allowable torque F is (yes), switching from the engine drive mode to the motor drive mode is allowed (step S6 ). Furthermore, the engine drive mode is switched to the motor drive mode (step S7 ). Such steps are carried out repeatedly.

As described above, in the hybrid vehicle according to the present embodiment, when the request drive torque T greater than the limit torque during the motor drive mode E is, the motor drive mode is switched to the engine drive mode to drive the engine 1 to restart. If the strap 3 is about to slip during the motor drive mode, the hybrid vehicle is therefore switched to the engine drive mode. In the engine drive mode, the hybrid vehicle can drive while maintaining an actual drive torque of the vehicle depending on the request drive torque T by driving the engine 1 without the mediation of the belt 3 efficiently. In this case, the deterioration in drivability can be prevented. Therefore, in the hybrid vehicle, the actual drive torque can be efficiently obtained depending on a request from a driver while the belt is slipping 3 is efficiently prevented, whereby a deterioration in drivability can be prevented. As described above, the switch to the motor drive mode is further prevented after the mode is changed to the engine drive mode. Even if the request drive torque T is not stabilized, repeated repetition of driving and stopping the engine may occur 1 can be prevented efficiently, one due to repetition on the belt 3 Exerted load can be reduced efficiently, so that the deterioration of drivability can be prevented efficiently.

In the hybrid vehicle according to the present embodiment, the torque setting unit sets 32 the limiting torque E so that it becomes smaller when the calculated value R the belt slip ratio 3 increases. Therefore, the slippage of the belt 3 can be prevented efficiently. Furthermore, there is a tendency that the slip ratio of the belt 3 increases when the deterioration of the belt 3 goes on. Consequently, with this determination, the deterioration of the belt can progress 3 be prevented.

In the hybrid vehicle according to the present embodiment, the permission torque is F less than the limiting torque E , Even if the request drive torque T is not stabilized, frequent repetition of driving and stopping the engine 1 can be prevented efficiently, one due to repetition on the belt 3 Exerted load can be reduced efficiently, so that a deterioration in drivability can be prevented efficiently. Furthermore, the drive control unit 31 in the state where the switch from the engine drive mode to the motor drive mode is prevented, allow the switch from the engine drive mode to the motor drive mode when the request drive torque T less than the allowable torque F is. Therefore, in the hybrid vehicle, in a state in which the drive torque can be efficiently obtained depending on a request from a driver, while the belt is slipping 3 is efficiently prevented, the state in which switching to the motor drive mode is prevented is returned to a normal state in which switching to the motor drive mode is permitted. That is, in the hybrid vehicle, the drive torque depending on a request from a driver can be efficiently obtained while the belt is slipping 3 is prevented efficiently so that the normal function can be performed.

In general, when the engine speed of the vehicle becomes high, the accelerator pedal position increases. In such a period of time of an accelerator pedal transition, the request drive torque fluctuates in many cases T significantly in a shorter period of time than in a case where the engine speed becomes low. In contrast, in the hybrid vehicle according to the present embodiment, the limiting torque E and the allowance torque F set so that when the captured value R1 the engine speed increases Difference between the limiting and the permitting torque E and F based on the same calculated value R the belt slip ratio 3 be set increases. Even if the engine speed increases and the demand drive torque T is not stabilized, the frequent repetition of driving and stopping the engine may consequently occur 1 can be prevented efficiently, one due to repetition on the belt 3 Exerted load can be reduced efficiently, so that the deterioration of drivability can be prevented efficiently.

The embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and the present invention can be modified and changed based on the technical concept of the present invention.

Reference list

1 ... engine, 2 ... motor generator (motor), 3 ... belt, 31 ... drive control unit, 32 ... torque setting unit, E ... limit torque, F ... permission torque, T ... request drive torque , R, R1, R2, R3 ... calculated value of the slip ratio, ω1 ... recorded value of the engine speed

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• JP 2006027598 A [0004]

Claims (4)

Hybrid vehicle that includes: an engine; an engine configured to assist rotation of the engine by providing a belt; a drive control unit configured to control the driving of the engine and the driving of the engine to determine a mode between a motor driving mode of driving by driving the motor in a state in which the driving of the engine is stopped and an engine driving mode of the To change driving by driving the engine; and a torque setting unit configured to set a limit torque, the limit torque being a threshold value for limiting a torque output from the engine to prevent the belt from slipping, wherein the drive control unit is configured to change the mode of operation to the engine drive mode to restart driving the engine and to prevent the change to the motor drive mode when the request drive torque is greater than the limit torque during the motor drive mode. Hybrid vehicle after Claim 1 , wherein the torque setting unit is configured to set the limit torque so that it becomes smaller as a slip ratio of the belt increases. Hybrid vehicle after Claim 1 or 2 wherein the torque setting unit is further configured to set an allowance torque, the allowance torque being a threshold value that allows the output of a torque from the engine, the allowance torque is less than the limit torque, and the drive control unit is configured to allow switching to the engine mode, when the request drive torque is less than the allow torque during the engine drive mode. Hybrid vehicle after Claim 3 , wherein the torque setting unit is configured to set the limit torque and the permission torque so that they decrease as the engine speed increases, and is configured to set a difference between the limit torque and the permission torque based on the same slip ratio of the belt become larger as the engine speed increases.

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