US-20260124926-A1 - BATTERY ELECTRIC VEHICLE

Abstract

A battery electric vehicle includes one or more processors that control an output of an electric motor and a gear stage of a transmission. When the battery electric vehicle is in an on-demand mode, the one or more processors acquire a maximum target drive force that is a maximum value of a target drive force acquirable at a current vehicle speed of the battery electric vehicle and a maximum realizable drive force that is a maximum value of a drive force that can be output by the battery electric vehicle at a current vehicle speed of the battery electric vehicle and a current gear stage of the transmission. When the maximum target drive force is greater than the maximum realizable drive force, the one or more processors shift the gear stage of the transmission down to a specified gear stage at a specified timing.

Inventors

• Kazuki Fujii

Assignees

• TOYOTA JIDOSHA KABUSHIKI KAISHA

Dates

Publication Date

20260507

Application Date

20250618

Priority Date

20241107

Claims (5)

1. 1 . A battery electric vehicle including an electric motor as a drive source, the battery electric vehicle comprising: a driving operation member used for driving; a transmission configured to change an output of the electric motor depending on a gear stage and transmit the changed output to drive wheels of the battery electric vehicle; one or more storage devices configured to manage a plurality of on-demand models that models a plurality of virtual mobilities with different driving environment characteristics for a driving operation of a driver; and one or more processors configured to control the output of the electric motor and the gear stage of the transmission, wherein the one or more processors are configured to, when the battery electric vehicle is in an on-demand mode, acquire, from the one or more storage devices, a target on-demand model corresponding to a target virtual mobility selected from among the virtual mobilities, calculate, based on an operation state of the driving operation member and a traveling state of the battery electric vehicle, using the target on-demand model, virtual acceleration of the target virtual mobility for the driving operation of the driver, calculate a target drive force of the battery electric vehicle for setting acceleration of the battery electric vehicle to be the virtual acceleration, control the output of the electric motor such that the target drive force is given to the battery electric vehicle, acquire a maximum target drive force that is a maximum value of the target drive force acquirable at a current vehicle speed of the battery electric vehicle, acquire a maximum realizable drive force that is a maximum value of a drive force outputtable by the battery electric vehicle at the current vehicle speed of the battery electric vehicle and a current gear stage of the transmission, and shift down the gear stage of the transmission to a specified gear stage at a specified timing when the maximum target drive force is greater than the maximum realizable drive force.
2. 2 . The battery electric vehicle according to claim 1 , wherein the specified gear stage is the gear stage at which the maximum realizable drive force is equal to or greater than the maximum target drive force or the gear stage at which a gear ratio is maximized.
3. 3 . The battery electric vehicle according to claim 1 , wherein, in a case where the target virtual mobility is a virtual mobility with a gear-shifting function, the specified timing is when the target virtual mobility is shifted down.
4. 4 . The battery electric vehicle according to claim 1 , wherein: the driving operation member includes an accelerator operation device; and the specified timing is when a specific operation that significantly changes the operation state of the accelerator operation device is performed.
5. 5 . The battery electric vehicle according to claim 1 , wherein the one or more processors are further configured to, when the battery electric vehicle is in the on-demand mode and when the gear stage of the transmission is the specified gear stage, acquire a current drive force of the battery electric vehicle, acquire, using the target on-demand model, a virtual drive force of the target virtual mobility for the driving operation of the driver, and add, to the target drive force, a difference obtained by subtracting the current drive force from the virtual drive force.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to Japanese Patent Application No. 2024-194994 filed on Nov. 7, 2024. The disclosure of the above-identified application, including the specification, drawings, and claims, is incorporated by reference herein in its entirety. BACKGROUND 1. Technical Field The present disclosure relates to a battery electric vehicle including an electric motor as a drive source. The present disclosure relates in particular to a battery electric vehicle including a transmission that changes an output of an electric motor depending on a gear stage and transmits the changed output to drive wheels. 2. Description of Related Art An electric motor can be controlled to output a desired motor torque by controlling a voltage or a magnetic field to be applied. By using this, a technique for reproducing various driving sensations in a battery electric vehicle by appropriately controlling an electric motor of the battery electric vehicle has been considered. As one of elements that characterize the driving sensation, there is a sense of acceleration of a driver to a driving operation. The sense of acceleration is a major point when the driver feels fun in driving. In particular, a preference for the sense of acceleration is different for each driver. In addition, the driver may want to enjoy a sense of acceleration of various mobilities depending on a mood of the driver. The inventors of the present disclosure use a plurality of models that models a plurality of virtual mobilities. The inventors of the present disclosure are considering an “on-demand mode” in which a sense of acceleration of the virtual mobilities is simulated in one battery electric vehicle. In the on-demand mode, control of the electric motor is performed to reproduce acceleration characteristics when a virtual mobility selected from among the virtual mobilities is driven, in the battery electric vehicle. In the related art, a battery electric vehicle including a transmission has been considered. For example, Japanese Unexamined Patent Application Publication No. 2019-178741 (JP 2019-178741 A) discloses a technique for improving driving performance by reducing a gear-shifting time with respect to the battery electric vehicle including the transmission. By providing the battery electric vehicle with the transmission, power performance of the battery electric vehicle can be improved. In addition, there is Japanese Unexamined Patent Application Publication No. 2018-166386 (JP 2018-166386 A) as a literature illustrating a technical level in this technical field. SUMMARY A case where the battery electric vehicle including the transmission travels in the on-demand mode is considered. The battery electric vehicle in the on-demand mode is controlled to reproduce the acceleration characteristics of the virtual mobility for the driving operation of the driver. Meanwhile, the transmission is controlled in accordance with a predetermined shift schedule in the battery electric vehicle. In particular, in the battery electric vehicle and the virtual mobility, a configuration of a powertrain is usually different. Therefore, a problem is that reproducibility of the acceleration characteristics of the virtual mobility deteriorates because shift down of a gear stage that does not appear in an operation of the virtual mobility occurs depending on the driving operation of the driver. Examples of such a case include a case where the driver performs kick down of an accelerator pedal to suddenly accelerate the battery electric vehicle while the battery electric vehicle is executing steady traveling at a medium speed to a high speed. The present disclosure has been made in consideration of the problem. One object of the present disclosure is to provide a technique capable of improving reproducibility of acceleration characteristics of a virtual mobility in a battery electric vehicle including a transmission. One aspect of the present disclosure relates to a battery electric vehicle including an electric motor as a drive source. The battery electric vehicle includes a driving operation member used for driving, a transmission, one or more storage devices, and one or more processors. The transmission changes an output of the electric motor depending on a gear stage and transmits the changed output to drive wheels of the battery electric vehicle. The one or more storage devices manage a plurality of on-demand models that models a plurality of virtual mobilities with different driving environment characteristics for a driving operation of a driver. The one or more processors control the output of the electric motor and the gear stage of the transmission. When the battery electric vehicle is in an on-demand mode, the one or more processors acquire, from the one or more storage devices, a target on-demand model corresponding to a target virtual mobility selected from among the virtual mobilities,calculate, based on an operation