WO2013035179A1

WO2013035179A1 - Vehicle and vehicle control method

Info

Publication number: WO2013035179A1
Application number: PCT/JP2011/070455
Authority: WO
Inventors: 英司福代
Original assignee: トヨタ自動車株式会社
Priority date: 2011-09-08
Filing date: 2011-09-08
Publication date: 2013-03-14

Abstract

When the previous drive torque command value is within a predetermined region including zero (zero cross region), an ECU (200) performs "zero crossing processing" (240), said zero crossing processing limiting a rate of change upper limit value (R) of the drive torque to a value smaller than the rate of change upper limit value (R) in a normal region other than the zero cross region. When performing this "zero crossing processing," the ECU mitigates the amount of a drop in the rate of change upper limit value (R) in a power mode to become lower than the amount of a drop in the rate of change upper limit value (R) in a non-power mode.

Description

Vehicle and vehicle control method

The present invention relates to control of driving torque for vehicle travel.

In JP 2009-184382 A (Patent Document 1), in a hybrid vehicle capable of switching between the power mode and the normal mode, the driving torque for traveling is set to a larger value in the power mode than in the normal mode. Is disclosed.

JP 2009-184383 A (Patent Document 2) discloses that in a hybrid vehicle capable of switching between a power mode, a normal mode, and an eco mode, in the power mode, in other modes (normal mode and eco mode). In comparison, it is disclosed that the driving torque for traveling is set to a large value.

JP 2009-184382 A JP 2009-184383 A

By the way, in the hybrid vehicle, when the positive / negative of the driving torque is switched (when the direction of the driving torque is switched between the acceleration direction and the deceleration direction), an abnormal noise generated in the power transmission path from the engine and the motor to the driving wheel is generated. In order to prevent this, there is a case where the upper limit value of the change rate of the drive torque when the drive torque is included in a predetermined region including zero (hereinafter referred to as “zero cross region”) is smaller than that in other regions. However,

Patent Documents

1 and 2 mentioned above do not specifically mention how to set the driving torque in such a zero-cross region according to each mode.

The present invention has been made in order to solve the above-described problems, and its purpose is to improve acceleration response in the power mode while suppressing abnormal noise generated when the driving torque is switched between positive and negative. It is.

A vehicle according to the present invention is configured to include at least a motor, and generates a driving torque of the vehicle with at least the torque of the motor, and controls the torque generating device so that the driving torque is within a predetermined region including zero. And a control device that performs a zero cross process for making the change rate upper limit value of the drive torque when it is included smaller than the change rate upper limit value when the drive torque is not included in the predetermined region. When performing the zero-cross processing, the control device sets the change rate upper limit value in the power mode in which acceleration response is more important than in the non-power mode to a value larger than the change rate upper limit value in the non-power mode.

Preferably, when the zero cross process is performed, the control device sets the change rate upper limit value to a smaller value as the drive torque is closer to zero in the non-power mode, and the change rate upper limit to be closer to zero in the power mode. While the value is set to a small value, it is set to a value larger than the change rate upper limit value in the non-power mode.

Preferably, the torque generator generates a drive torque by a motor torque.
Preferably, the torque generating device further includes an engine in addition to the motor, and generates a driving torque with power of at least one of the motor and the engine.

A vehicle control method according to another aspect of the present invention is a vehicle control method for generating a drive torque of a vehicle with at least a motor torque, and determines whether or not the drive torque is included in a predetermined region including zero. And a step of performing a zero-cross process for making the change rate upper limit value of the drive torque when the drive torque is included in the predetermined region smaller than the change rate upper limit value when the drive torque is not included in the predetermined region. In the zero cross processing step, when performing the zero cross processing, the change rate upper limit value in the power mode where acceleration response is more important than in the non-power mode is set to a value larger than the change rate upper limit value in the non-power mode. Set.

According to the present invention, it is possible to improve acceleration response in the power mode while suppressing abnormal noise that occurs when switching between positive and negative driving torque.

1 is an overall block diagram of a vehicle. It is the figure which showed the state of the engine, 1st MG, and 2nd MG on the alignment chart. It is a functional block diagram of ECU. It is a figure which shows typically an example of map (alpha) and (beta) for setting the change rate upper limit R of a drive torque. It is a flowchart which shows the process sequence of ECU. It is the figure which illustrated the mode of the time change of each state quantity, such as change rate upper limit R in a present Example.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

FIG. 1 is an overall block diagram of a vehicle 1 according to an embodiment of the present invention. Referring to FIG. 1, vehicle 1 includes a torque generator 2, a speed reducer 50, a drive shaft 51, drive wheels 80, and an ECU (Electronic Control Unit) 200.

The torque generator 2 generates drive torque for running the vehicle 1. The torque generator 2 includes an engine 10, a first MG (Motor Generator) 20, a second MG 30, a power split device 40, a PCU (Power Control Unit) 60, and a battery 70.

Engine 10, first MG 20 and second MG 30 are connected via power split device 40. The vehicle 1 travels with driving force output from at least one of the engine 10 and the second MG 30. The power generated by the engine 10 is divided into two paths by the power split device 40. That is, one is a path transmitted to the drive wheel 80 via the speed reducer 50 and the other is a path transmitted to the first MG 20.

The engine 10 is controlled by a control signal S1 from the ECU 200. First MG 20 and second MG 30 are AC motors, for example, three-phase AC synchronous motors. First MG 20 generates power using the power of engine 10 divided by power split device 40. Second MG 30 generates a driving force using at least one of the electric power stored in battery 70 and the electric power generated by first MG 20. Then, the driving force of the second MG 30 is transmitted to the driving wheels 80 via the speed reducer 50. When the vehicle is braked, the second MG 30 is driven by the drive wheels 80 via the speed reducer 50, and the second MG 30 operates as a generator. Thereby, 2nd MG30 functions also as a regenerative brake which converts kinetic energy of vehicles into electric power. The regenerative power generated by second MG 30 is stored in battery 70.

The power split device 40 includes a planetary gear including a sun gear, a pinion gear, a carrier, and a ring gear. The pinion gear engages with the sun gear and the ring gear. The carrier supports the pinion gear so as to be capable of rotating, and is connected to the crankshaft of the engine 10. The sun gear is connected to the rotation shaft of the first MG 20. The ring gear is connected to the rotation shaft of second MG 30 and speed reducer 50. As described above, the engine 10, the first MG 20 and the second MG 30 are connected via the power split device 40 made of planetary gears, so that the rotational speed of the engine 10 (hereinafter referred to as “engine rotational speed Ne”), the first MG 20 The rotational speed (hereinafter referred to as “first MG rotational speed Nm1”) and the rotational speed of the second MG 30 (hereinafter referred to as “second MG rotational speed Nm2”) are connected by a straight line in the nomographic chart (see FIG. 2 described later). .

The PCU 60 is controlled by a control signal S2 from the ECU 200. PCU 60 converts the DC power stored in battery 70 into AC power that can drive first MG 20 and second MG 30 and outputs the converted AC power to first MG 20 and / or second MG 30. Thereby, first MG 20 and / or second MG 30 are driven by the electric power stored in battery 70. Further, the PCU 60 converts the AC power generated by the first MG 20 and / or the second MG 30 into DC power that can charge the battery 70 and outputs the DC power to the battery 70. Thereby, battery 70 is charged with the electric power generated by first MG 20 and / or second MG 30.

The battery 70 is a DC power source that stores electric power for driving the first MG 20 and / or the second MG 30, and is formed of, for example, a secondary battery such as nickel metal hydride or lithium ion. The voltage of the battery 70 is about 200V, for example. Note that a large-capacity capacitor can also be used as the battery 70.

Also, the ECU 200 is connected with a rotation speed sensor 11,

resolvers

12, 13, a vehicle speed sensor 14, an accelerator position sensor 15, a mode sensor 16, an acceleration sensor 17, and the like.

Rotational speed sensor 11 detects engine rotational speed (rotational speed of crankshaft of engine 10) Ne. The resolver 12 detects the first MG rotation speed Nm1. The resolver 13 detects the second MG rotation speed Nm2. The vehicle speed sensor 14 detects the vehicle speed V from the rotational speed of the drive shaft. The accelerator position sensor 15 detects an accelerator pedal operation amount A by the user. The mode sensor 16 detects the state of a power switch (not shown) that is pressed by the user when the user requests traveling in the power mode. The power mode is a mode in which the acceleration response of the vehicle 1 is more important than the non-power mode. If the accelerator pedal operation amount A is the same, the driving torque in the power mode is controlled to a value larger than the driving torque in the non-power mode. When the power switch is pressed once, the power mode is selected, and when the power switch is pressed again, the selection of the power mode is canceled and the non-power mode is selected. The non-power mode may include a plurality of modes (for example, a normal mode and a fuel consumption mode in which fuel consumption is more important than the normal mode). The acceleration sensor 17 detects an acceleration G acting in the vehicle longitudinal direction. Each of these sensors transmits a signal representing the detection result to ECU 200.

The ECU 200 includes a CPU (Central Processing Unit) (not shown) and a memory, and is configured to execute a predetermined calculation process based on information stored in the memory and information from each sensor.

The ECU 200 generates a driving torque Tp for causing the vehicle 1 to travel with the power of at least one of the engine 10 and the second MG 30 from the torque generator 2 and applies the driving torque Tp to the driving shaft 51.

FIG. 2 is a diagram showing the states of the engine 10, the first MG 20, and the second MG 30 controlled by the ECU 200 on an alignment chart. Hereinafter, the torque of the engine 10 is referred to as “engine torque Te”, the torque of the first MG 20 is referred to as “first MG torque Tm1”, and the torque of the second MG 30 is referred to as “second MG torque Tm2”.

As described above, the engine rotational speed Ne, the first MG rotational speed Nm1, and the second MG rotational speed Nm2 are connected by a straight line in the alignment chart. The second MG rotation speed Nm2 is a value corresponding to the vehicle speed V. In FIG. 2, “Tep” indicates the torque (hereinafter referred to as “engine direct torque”) at which the engine torque Te is transmitted to the ring gear of the power split device 40. Therefore, in this embodiment, the sum of the second MG torque Tm2 and the engine direct torque Tep is the drive torque Tp.

In the vehicle 1 having the above-described configuration, the ECU 200 sets an upper limit value (hereinafter, also referred to as “change rate upper limit value R”) of the change rate (change amount per unit time) of the drive torque Tp, and the drive torque Control is performed so that the actual change rate of Tp does not exceed the change rate upper limit value R.

By the way, when the action direction of the drive torque Tp is switched between the negative direction (deceleration direction) and the positive direction (acceleration direction), it is provided on the power transmission path from the engine 10, the first MG 20, the second MG 30 to the drive wheels 80. There is a case where an abnormal noise (so-called rattling noise) or a shock is generated due to clogging of a backlash of a generated gear (for example, a power reduction device 40 (planetary gear) provided in the reduction gear 50 or the torque generator 2). . In order to prevent such noise and shock, the ECU 200 determines the change rate upper limit R when the drive torque Tp is included in a predetermined region (zero cross region) including zero in the normal region other than the zero cross region. Processing for making the change rate upper limit value R smaller (hereinafter also referred to as “zero cross processing”) is performed.

When performing this “zero cross processing”, the ECU 200 does not uniformly reduce the change rate upper limit value R, but changes the amount of decrease in the change rate upper limit value R depending on whether or not it is in the power mode. More specifically, the ECU 200 considers that the importance of the acceleration response is higher in the power mode than in the non-power mode than in the noise and shock suppression, and the change rate upper limit value R in the power mode. Is reduced more than the reduction amount (limit amount) of the change rate upper limit value R in the non-power mode. This is the most characteristic point of the present invention.

FIG. 3 is a functional block diagram of the ECU 200 when the zero cross process is performed. Each functional block shown in FIG. 3 may be realized by hardware or software.

ECU 200 includes a zero-cross determination unit 210, a rate upper limit setting unit 220, a drive torque command value setting unit 250, and a storage unit 260. The rate upper limit setting unit 220 includes a normal processing unit 230 and a zero cross processing unit 240.

The zero cross determination unit 210 reads the previous value of the drive torque command value Tpcom (hereinafter also referred to as “drive torque command previous value Tpcom (n−1)”) from the storage unit 260, and drives the drive torque command previous value Tpcom (n−1). ) Is included in the zero cross region.

When the drive torque command previous value Tpcom (n−1) is included in the normal region other than the zero cross region, the change rate upper limit value R is set by the normal processing unit 230. The normal processing unit 230 sets the change rate upper limit value R to the positive upper limit fixed value Rmax (+) when the drive torque command previous value Tpcom (n−1) is positive, and sets the drive torque command previous value Tpcom (n). When -1) is negative, the change rate upper limit value R is set to the negative upper limit fixed value Rmax (-). The positive upper limit fixed value Rmax (+) and the negative upper limit fixed value Rmax (−) may be the same value.

On the other hand, when the drive torque command previous value Tpcom (n−1) is included in the zero cross region, the change rate upper limit value R is set by the zero cross processing unit 240. The zero cross processing unit 240 limits the change rate upper limit value R in the zero cross region to the change rate upper limit value R in the normal region. More specifically, when the drive torque command previous value Tpcom (n−1) is positive, the change rate upper limit value R is set to a value smaller than the positive side upper limit fixed value Rmax (+), and the drive torque command previous value Tpcom is set. When (n−1) is negative, the change rate upper limit R is set to a value smaller than the negative upper limit fixed value Rmax (−). This processing is “zero cross processing”.

When performing the “zero cross processing”, the zero cross processing unit 240 reduces the amount of decrease in the change rate upper limit value R in the power mode more than the amount of decrease in the change rate upper limit value R in the non-power mode.

The zero cross processing unit 240 includes a power mode determination unit 241 and a restriction unit 242.
The power mode determination unit 241 determines whether it is in the power mode or the non-power mode based on the output of the mode sensor 16.

The restriction unit 242 sets the change rate upper limit value R using the power mode map α when the power mode is set. On the other hand, in the non-power mode, limiting unit 242 sets change rate upper limit R using non-power mode map β.

FIG. 4 is a diagram schematically showing an example of the maps α and β for setting the change rate upper limit value R of the drive torque. In FIG. 4, the region where the drive torque command previous value Tpcom (n−1) shown on the horizontal axis is from the predetermined value T1 (<0) to the predetermined value T2 (> 0) is the “zero cross region”. The area is a normal area.

As shown in FIG. 4, the change rate upper limit value R set in the non-power mode map β is set to a smaller value as the drive torque command previous value Tpcom (n−1) is closer to zero. The change rate upper limit R set in the power mode map α is also set to a smaller value as the drive torque command previous value Tpcom (n−1) is closer to 0, but the change rate upper limit in the non-power mode. A value larger than R is set. That is, the decrease amount (limit amount) of the change rate upper limit value R set in the power mode map α is more relaxed than the decrease amount (limit amount) of the change rate upper limit value R in the non-power mode. As a result, even in the zero cross region, the driving force response in the power mode can be improved more than the driving force response in the non-power mode, and the user's request can be answered.

Returning to FIG. 3, the drive torque command value setting unit 250 performs control so that the actual change rate of the drive torque command value Tpcom does not exceed the change rate upper limit value R set by the normal processing unit 230 or the zero cross processing unit 240. To do. Specifically, the drive torque command value setting unit 250 obtains a drive torque Tp requested by the user from the vehicle speed V, the accelerator pedal operation amount A, and the like (hereinafter referred to as “drive torque request value Tpreq”), and this drive torque request It is determined whether or not the value Tpreq is more than the change rate upper limit value R with respect to the drive torque command previous value Tpcom (n−1). If the drive torque request value Tpreq is not more than the change rate upper limit value R with respect to the drive torque command previous value Tpcom (n−1), the drive torque request value Tpreq is directly used as the current value of the drive torque command value Tpcom (hereinafter referred to as the drive torque command value Tpcom , Also referred to as “driving torque command current value Tpcom (n)”). Otherwise, the value obtained by adding the change rate upper limit value R to the previous driving torque command value Tpcom (n−1) or the previous value of the driving torque command. A value obtained by subtracting the change rate upper limit value R from Tpcom (n−1) is set as the drive torque command current value Tpcom (n).

Then, the drive torque command value setting unit 250 outputs a control signal for controlling the actual drive torque Tp to the drive torque command current value Tpcom (n) to the torque generator 2.

The storage unit 260 stores the drive torque command current value Tpcom (n). The drive torque command current value Tpcom (n) stored in the storage unit 260 is used as the drive torque command previous value Tpcom (n−1) in the next cycle.

FIG. 5 is a flowchart showing a processing procedure of the ECU 200 for realizing the above-described functions. This flowchart is repeatedly executed in a predetermined cycle.

In S10, ECU 200 reads drive torque command previous value Tpcom (n-1) stored in the previous cycle.

In S11, ECU 200 determines whether or not drive torque command previous value Tpcom (n-1) is included in the zero cross region.

When drive torque command previous value Tpcom (n−1) is included in the zero cross region (YES in S11), ECU 200 determines in S12 whether or not it is in the power mode. When in power mode (YES in S12), ECU 200 sets change rate upper limit value R in S13 using map α for power mode shown in FIG. On the other hand, when the current mode is the non-power mode (NO in S12), ECU 200 sets change rate upper limit R in S14 using map β for non-power mode shown in FIG.

On the other hand, when drive torque command previous value Tpcom (n−1) is included in the normal region (NO in S11), ECU 200 performs normal processing. That is, ECU 200 determines whether or not drive torque command previous value Tpcom (n−1) is positive in S15. If it is positive (YES in S15), ECU 200 determines change rate upper limit value R in S16. Positive upper limit fixed value Rmax (+) is set, and if negative (NO in S15), change rate upper limit value R is set to negative upper limit fixed value Rmax (-) in S17.

In S18, ECU 200 calculates drive torque request value Tpreq from vehicle speed V, accelerator pedal operation amount A, and the like.

In S19, as described above, ECU 200 sets drive torque command current value Tpcom (n) from drive torque request value Tpreq and change rate upper limit value R. That is, when the drive torque request value Tpreq is not more than the change rate upper limit value R with respect to the drive torque command previous value Tpcom (n−1), the ECU 200 uses the drive torque request value Tpreq as it is as the drive torque command current value Tpcom ( n), otherwise, the value obtained by adding the change rate upper limit value R to the drive torque command previous value Tpcom (n-1) or the change rate upper limit value R from the drive torque command previous value Tpcom (n-1). The reduced value is set to the drive torque command current value Tpcom (n).

In S20, the ECU 200 outputs a control signal for controlling the actual drive torque Tp to the drive torque command current value Tpcom (n) to the torque generator 2.

In S21, ECU 200 stores drive torque command current value Tpcom (n).
FIG. 6 exemplifies a state of time change of each state quantity (vehicle speed V, accelerator pedal operation amount A, drive torque command value Tpcom, acceleration G, change rate upper limit value R) such as the change rate upper limit value R in the present embodiment. FIG.

Prior to time t1, the accelerator pedal operation amount A is substantially zero, and the drive torque command value Tpcom is set slightly on the negative side (deceleration side) from zero.

When the accelerator pedal is depressed at time t1, the drive torque command value Tpcom starts to increase, and at time t2, the drive torque command value Tpcom is switched from negative (deceleration direction) to positive (acceleration direction). At this time, the change rate upper limit value R in the zero cross region is lower than the change rate upper limit value R in the normal region by the above-described zero cross processing, so that rattling noise and shock are prevented.

In this zero crossing process, in this embodiment, as shown in FIG. 6, the amount of decrease in the change rate upper limit value R is changed depending on whether or not the power mode is in effect. That is, the amount of decrease in the change rate upper limit value R (solid line) in the power mode is more moderate than the amount of decrease in the change rate upper limit value R (dotted line) in the non-power mode. As a result, even in the zero cross region, the driving force response (acceleration response) in the power mode can be improved compared to the non-power mode, and the user's request can be answered.

As described above, in the vehicle 1 according to this embodiment, when the zero cross process is performed, the amount of decrease in the drive torque change rate upper limit value R in the power mode is set to the decrease in the drive torque change rate upper limit value R in the non-power mode. Relax more than the amount. As a result, the acceleration response in the power mode can be improved while suppressing the noise generated when the sign of the driving torque is switched.

The present embodiment can be modified as follows, for example.
In the present embodiment, the target of the zero cross process is “drive torque”, but the target of the zero cross process may be the first MG torque Tm1 or the second MG torque Tm2. That is, the zero cross process of the first MG torque Tm1 or the second MG torque Tm2 may be performed in a region where the state of the first MG 20 or the second MG 30 is switched between power running and regeneration.

In the present embodiment, the case where the vehicle 1 is a hybrid vehicle that generates the drive torque Tp by the power of at least one of the engine 10 and the second MG 30 has been described. However, the present invention does not include an engine and uses the torque of the motor. The present invention can also be applied to an electric vehicle that generates driving torque. In such an electric vehicle, since the motor torque becomes the driving torque, the region where the state of the motor is switched between power running and regeneration coincides with the region where the positive / negative driving torque is switched (zero cross region). Therefore, the zero cross process may be performed in a region where the motor state is switched between power running and regeneration.

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 vehicle, 2 torque generator, 10 engine, 11 rotation speed sensor, 12, 13 resolver, 14 vehicle speed sensor, 15 accelerator position sensor, 16 mode sensor, 17 acceleration sensor, 20 1st MG, 30 2nd MG, 40 power split device , 50 reducer, 51 drive shaft, 70 battery, 80 drive wheel, 200 ECU, 210 zero cross determination unit, 220 rate upper limit setting unit, 230 normal processing unit, 240 zero cross processing unit, 241 power mode determination unit, 242 limiting unit 250 drive torque command value setting unit, 260 storage unit.

Claims

A torque generator (2) configured to include at least a motor (30), and generating a drive torque of the vehicle by at least the torque of the motor;
By controlling the torque generator, the change rate upper limit value when the drive torque is not included in the predetermined region is set as the change rate upper limit value of the drive torque when the drive torque is included in the predetermined region including zero. A control device (200) that performs zero-cross processing to make the value smaller than the value,
The control device, when performing the zero-cross processing, the change rate upper limit value in the power mode in which acceleration response is more important than in the non-power mode is larger than the change rate upper limit value in the non-power mode The vehicle to set to the value.
When performing the zero-crossing process, the control device sets the upper limit value of the change rate to a smaller value as the driving torque is closer to zero in the non-power mode, and the driving torque is closer to zero in the power mode. The vehicle according to claim 1, wherein the vehicle is set to a value larger than the change rate upper limit value in the non-power mode while setting the change rate upper limit value to a smaller value.
The vehicle according to claim 1, wherein the torque generator generates the driving torque by the torque of the motor.
The vehicle according to claim 1, wherein the torque generation device further includes an engine (10) in addition to the motor, and generates the drive torque with at least one of the power of the motor and the engine.
A vehicle control method for generating a drive torque of a vehicle with at least the torque of a motor (30),
Determining whether the driving torque is included in a predetermined region including zero;
Performing a zero cross process for making the change rate upper limit value of the drive torque when the drive torque is included in the predetermined region smaller than the change rate upper limit value when the drive torque is not included in the predetermined region; Including
The step of performing the zero cross processing includes the change rate upper limit value in the power mode in which acceleration response is more important than in the non-power mode when performing the zero cross processing, and the change rate upper limit value in the non-power mode. The vehicle control method is set to a larger value.