阅读说明：本技术 燃料电池车 (Fuel cell vehicle ) 是由 深见龙也 于 2021-02-08 设计创作，主要内容包括：本发明提供一种燃料电池车,具备向行驶用的电动马达供给电力的蓄电池和燃料电池。控制电动马达的控制器将从燃料电池的启动开始起规定时间的期间的电动马达的输出转矩的最大增加比率设定为第1上限比率。控制器将经过规定时间后的输出转矩的最大增加比率设定为大于第1上限比率的第2上限比率。(The invention provides a fuel cell vehicle, which is provided with a storage battery and a fuel cell for supplying power to an electric motor for driving. The controller for controlling the electric motor sets the maximum increase rate of the output torque of the electric motor for a predetermined time period from the start of the fuel cell to the 1 st upper limit rate. The controller sets a 2 nd upper limit ratio that is larger than the 1 st upper limit ratio to a maximum increase ratio of the output torque after a predetermined time has elapsed.)

1. A fuel cell vehicle comprising a battery for supplying electric power to an electric motor for traveling and a fuel cell,

a controller for controlling the electric motor sets a 1 st upper limit ratio as a maximum increase ratio of an output torque of the electric motor for a predetermined time from a start of the fuel cell, and sets a 2 nd upper limit ratio larger than the 1 st upper limit ratio as the maximum increase ratio after the predetermined time has elapsed.

2. The fuel cell vehicle according to claim 1,

the 1 st upper limit ratio is set such that a time from a maximum output torque when the electric motor is driven only by the battery to a maximum output torque after the fuel cell is started is longer than a start time of the fuel cell at the 1 st upper limit ratio.

3. The fuel cell vehicle according to claim 1 or 2,

the predetermined time is set to a time from a maximum output torque when the electric motor is driven only by the battery to a maximum output torque after the fuel cell is started at the 1 st upper limit ratio.

4. The fuel cell vehicle according to any one of claims 1 to 3,

the controller sets the maximum increase ratio during the predetermined time to the 1 st upper limit ratio when an accelerator opening immediately before the fuel cell is started exceeds a predetermined 1 st opening,

when the accelerator opening degree immediately before the fuel cell is started is lower than the 1 st opening degree, the controller sets the maximum increase ratio during the predetermined time to a 3 rd upper limit ratio, which is greater than the 1 st upper limit ratio and equal to or less than the 2 nd upper limit ratio.

Technical Field

The technology disclosed in the present specification relates to a fuel cell vehicle including a battery and a fuel cell that supply electric power to an electric motor for traveling.

Background

A fuel cell vehicle including a battery and a fuel cell is disclosed in japanese patent laid-open nos. 2008-301542 and 2008-312418. The fuel cell vehicle disclosed in these documents can travel using only the electric power of the battery from before the fuel cell is started.

The maximum output of the battery is smaller than the maximum output of the fuel cell. When traveling using only the electric power of the battery, the output torque of the electric motor is limited. When the fuel cell is started, the upper limit of the output torque of the electric motor is increased. If the fuel cell is started while the driver is stepping on the accelerator and the output torque of the electric motor is suddenly increased, there is a possibility that the driver feels a sense of discomfort.

Disclosure of Invention

The controller of the fuel cell vehicle disclosed in the present specification sets the maximum increase rate of the output torque of the electric motor for a predetermined time period from the start of the fuel cell to the 1 st upper limit rate, and sets the maximum increase rate after the predetermined time period has elapsed to the 2 nd upper limit rate that is greater than the 1 st upper limit rate. By suppressing the maximum increase rate during a predetermined time period from the start of the fuel cell to be lower than the upper limit rate (2 nd upper limit rate) in a normal state, a sudden increase in the output torque can be suppressed, and a sense of discomfort given to the driver can be suppressed.

The 1 st upper limit ratio can be set as follows. The time until the output torque of the electric motor reaches the 2 nd maximum output torque from the 1 st maximum output torque at the 1 st upper limit ratio is longer than the start time of the fuel cell. The 1 st maximum output torque is the maximum output torque when the vehicle travels only with the battery, and the 2 nd maximum output torque is the maximum output torque after the fuel cell is started. If the starting time elapses, the electric motor can output the 2 nd maximum output torque, but if the output torque of the electric motor is rapidly increased at the starting time, a large uncomfortable feeling is given to the driver. Therefore, by setting the 1 st upper limit ratio as described above, the sense of discomfort given to the driver can be suppressed.

Even when the driver steps on the accelerator with force during the start of the fuel cell, the uncomfortable feeling is small even if the increase rate of the output torque is large. In other words, when the change in the accelerator opening degree is large, the driver feels little discomfort even if the change in the output torque is large. In view of this, the controller may employ the following control rules. When the accelerator opening immediately before the fuel cell is started exceeds a predetermined 1 st opening, the controller sets the maximum increase rate for a predetermined time period to the 1 st upper limit rate. When the accelerator opening degree immediately before the fuel cell is started is lower than the 1 st opening degree, the controller sets the maximum increase ratio of the output torque for a predetermined time period to the 3 rd upper limit ratio. The 3 rd upper limit ratio is larger than the 1 st upper limit ratio and is equal to or smaller than the 2 nd upper limit ratio.

Detailed techniques and further modifications disclosed in the present specification will be described in the following detailed description.

Drawings

Features, advantages, technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and wherein:

fig. 1 is a block diagram of a fuel cell vehicle of the embodiment.

Fig. 2A is a graph of the maximum output torque of the electric motor.

Fig. 2B is a graph of the maximum increase rate of the output torque of the electric motor.

Detailed Description

Fig. 1 shows a block diagram of a fuel cell vehicle 2 of the embodiment. The fuel cell vehicle 2 obtains electric power from the fuel cell 3 and the main battery 4, and travels by the electric motor 6. The fuel cell 3 is connected in parallel with the main battery 4. The outputs of the fuel cell 3 and the main battery 4 are converted into ac power by a power converter 5 and supplied to an electric motor 6 for running. Further, a boost converter may be connected between the fuel cell 3 and the power converter 5 (or between the fuel cell 3 and the main battery 4). A bidirectional voltage converter may be connected between the main battery 4 and the power converter 5. The dotted lines in fig. 1 indicate signal lines.

The main battery 4 is connected to an input terminal of a buck converter 7, and the output terminal of the buck converter 7 is connected to a sub-battery 8. The output voltage of the main battery 4 exceeds 100 volts, and the output voltage of the sub-battery 8 is lower than 50 volts. The step-down converter 7 steps down the output power of the main battery 4 or the fuel cell 3 to charge the sub-battery 8.

The electric power of the sub-battery 8 is supplied to a device that operates at a voltage of less than 50 volts. The devices operated by the electric power of the sub-battery 8 include low-power devices such as a radio 20 and various controllers (computers). Various auxiliary devices attached to the fuel cell 3 are also supplied with electric power from the sub-battery 8.

The fuel cell 3 and the power converter 5 are controlled by a controller 10. The controller 10 is connected to sensors such as a main switch 11, an accelerator pedal sensor 12, and a vehicle speed sensor 13 of the fuel cell vehicle 2. The accelerator pedal sensor 12 measures an opening degree of an accelerator pedal (accelerator opening degree). If the main switch 11 is turned on, the controller 10 starts the fuel cell 3. The controller 10 determines the output torque of the electric motor 6 based on information such as the opening degree of an accelerator pedal or a brake pedal (not shown) and the vehicle speed. The controller 10 controls the fuel cell 3 and the power converter 5 based on the determined output torque.

The start-up of the fuel cell 3 requires a prescribed time. Although it takes time to start the fuel cell 3, the fuel cell vehicle 2 can start traveling with the electric power of the main battery 4 immediately after the main switch 11 is turned on. However, the maximum output of the main battery 4 is smaller than the maximum output of the fuel cell 3. Therefore, the maximum output torque of the electric motor 6 is small before the fuel cell 3 is started. When the fuel cell 3 is started, the maximum output torque of the electric motor 6 rapidly increases. If the fuel cell 3 is started and the output torque of the electric motor 6 suddenly increases while the driver steps on the accelerator with a constant force, there is a possibility that the driver will be given a sense of discomfort. During the start-up of the fuel cell 3, the fuel cell vehicle 2 can suppress the increase rate of the output torque of the electric motor 6, and can suppress the uncomfortable feeling given to the driver.

The controller 10 determines the increase rate of the output torque according to the accelerator opening. The larger the accelerator opening degree is, the larger the increase ratio is. An upper limit value (maximum increase ratio) of the increase ratio is set in the controller 10, and the controller 10 suppresses the increase ratio of the output torque to the maximum increase ratio or less.

Fig. 2A shows a graph of the maximum output torque of the electric motor 6, and fig. 2B shows a graph of the maximum increase ratio of the output torque. The vertical axis of fig. 2A represents the output torque of the electric motor 6, and the horizontal axis represents time. The vertical axis of fig. 2B represents the increase rate, and the horizontal axis represents time.

The main switch 11 is turned on at time T0. After the main switch 11 is turned on, a period of time is required for the start preparation of the fuel cell 3. In fig. 2A and 2B, the time from the time T0 to the time T1 (the start preparation period Pr) is the time required for preparation for start. The fuel cell vehicle 2 can travel by the electric power of the main battery 4 until the fuel cell 3 starts to start. The maximum output torque of the electric motor 6 when running only on the main battery 4 is the 1 st maximum output torque Tm 1. Wherein the maximum output torque after the start of the fuel cell 3 is the 2 nd maximum output torque Tm 2. In the medium/high vehicle speed region, the maximum output torque of the electric motor 6 depends on the vehicle speed. Fig. 2A and 2B are graphs showing changes in the maximum output torque in a low vehicle speed region where the maximum output torque does not depend on the vehicle speed.

The start-up of the fuel cell 3 starts at time T1. At time T1, the supply of the fuel gas and the oxidizing gas to the fuel cell 3 is started, and the output of electric power from the fuel cell 3 is started. When the electric power starts to be output from the fuel cell 3, the maximum output torque of the electric motor 6 also increases. The start-up of the fuel cell 3 is completed at time T2. The time from the time T1 to the time T2 is the start time Ps of the fuel cell 3.

The fuel cell vehicle 2 can immediately start running from time T0 using the electric power of the main battery 4. The maximum output torque of the electric motor 6 (1 st maximum output torque Tm1) in the case of running with only the electric power of the main battery 4 is smaller than the maximum output torque (2 nd maximum output torque Tm2) in the case of running with the electric power of the fuel cell 3. During the period from the time T1 to the time T2, the maximum output torque of the electric motor 6 increases from the 1 st maximum output torque Tm1 to the 2 nd maximum output torque Tm 2. However, the controller 10 limits the increase rate of the output torque of the electric motor 6 during a period immediately after the start of the fuel cell 3.

As shown in fig. 2B, the controller 10 sets the maximum increase rate of the output torque of the electric motor 6 to the 1 st upper limit rate dTm1 for a predetermined time P1 from the start of the fuel cell 3 (time T1). Further, the controller 10 also sets the maximum increase rate in the electric power running using only the main battery 4 to the 1 st upper limit rate dTm 1. After the prescribed time P1 elapses, the controller 10 changes the maximum increase ratio from the 1 st upper limit ratio dTm1 to the 2 nd upper limit ratio dTm 2. The 2 nd upper limit ratio dTm2 is greater than the 1 st upper limit ratio dTm 1.

As described previously, the fuel cell 3 starts starting at the time T1, and the starting is completed at the time T2. When the upper limit is not set to the output torque, the output torque of the electric motor 6 can be increased at the 2 nd upper limit ratio dTm2 at maximum (see a curve G2 in fig. 2A). When the driver depresses the accelerator pedal with force at the start of the fuel cell 3 (time T1), the output torque of the electric motor 6 increases abruptly from time T1. If the output torque suddenly increases even though the opening degree of the accelerator pedal is constant, the driver feels a sense of discomfort. During a predetermined time P1 from the start of the fuel cell 3, the controller 10 limits the increase rate of the output torque of the electric motor 6 to the 1 st upper limit rate dTm1 or less. Therefore, the output torque of the electric motor 6 also increases at maximum along the curve G1 of fig. 2A. The fuel cell vehicle 2 of the embodiment can suppress a sense of discomfort given to the driver at the time of start-up of the fuel cell 3.

In fig. 2A, the increase rate limited by the start-up of the fuel cell 3 is represented by the 2 nd upper limit rate dTm 2. Since the 2 nd upper limit ratio dTm2 is the maximum increase ratio after the fuel cell 3 is started, it may not necessarily coincide with the curve G2 of fig. 2A. Wherein the 2 nd upper limit ratio dTm2 is greater than the 1 st upper limit ratio dTm 1.

The 1 st upper limit ratio dTm1 is set such that the time (time P1 in fig. 2A) until the torque of the electric motor 6 reaches the 2 nd maximum torque Tm2 from the 1 st maximum torque Tm1 at the 1 st upper limit ratio dTm1 is longer than the start time Ps of the fuel cell 3. The fuel cell 3 has the capability of increasing the maximum output torque from the 1 st maximum output torque to the 2 nd maximum output torque at the start time Ps, but by setting the maximum increase rate of the output torque of the electric motor 6 to the 1 st upper limit rate dTm1 (< the 2 nd upper limit rate dTm2), the sense of discomfort given to the driver can be suppressed.

The predetermined time P1 is set as the time required for the torque of the electric motor 6 to reach the 2 nd maximum torque Tm2 from the 1 st maximum torque Tm1 at the 1 st upper limit ratio dTm 1. When the accelerator opening is 100% at the start of the fuel cell 3 (time T1), the maximum output torque of the electric motor 6 reaches the 2 nd maximum output torque Tm2 at a predetermined time P1. Even in the case where the accelerator opening degree is 100%, the increase rate of the output torque is kept constant until the 2 nd maximum output torque Tm2 is reached.

When the accelerator opening immediately before the start of the fuel cell 3 is lower than the 1 st opening, the controller 10 sets the maximum increase rate for the period of the predetermined time P1 to the 3 rd upper limit rate dTm 3. In fig. 2A and 2B, a curve G3 indicated by a one-dot chain line represents the case of the 3 rd upper limit ratio dTm 3. As shown in fig. 2A and 2B, the 3 rd upper limit ratio dTm3 is greater than the 1 st upper limit ratio dTm1 and is equal to or less than the 2 nd upper limit ratio dTm 2. The reason for increasing the upper limit ratio when the accelerator opening degree immediately before the start of the fuel cell 3 is lower than the predetermined 1 st opening degree is as follows.

Even when the driver steps on the accelerator with force during the start-up of the fuel cell 3, the driver is less uncomfortable even if the increase rate is large. In other words, when the change in the accelerator opening degree is large, the driver feels little discomfort even if the change in the output torque is large. Therefore, when the accelerator opening degree immediately before the start of the fuel cell 3 is lower than the predetermined 1 st opening degree, the controller 10 sets the maximum increase ratio for a predetermined time period to the 3 rd upper limit ratio dTm 3. When the change in the accelerator opening degree is large, the acceleration performance of the vehicle can be improved. The 1 st opening degree is set to, for example, 60 [% ].

The electric motor 6 operates by the electric power supplied from the power converter 5. Therefore, by suppressing the increase rate of the electric power supplied to the electric motor 6, the increase rate of the output torque of the electric motor 6 can be suppressed. The increase ratio dPm of the electric power supplied to the electric motor 6 can be determined by the following (formula 1) using the increase ratio of the output torque (for example, the 1 st upper limit ratio dTm 1).

[ equation 1]

The meanings of the symbols used in (formula 1) are as follows.

dt: control period of the power converter 5

Pm 1: supply of electric power to the electric motor 6 in the current control cycle

Pm 2: supply of electric power to the electric motor 6 in the next control cycle

Nm 1: current rotational speed of electric motor 6

Nm 2: predetermined rotation speed of the electric motor 6 in the next control cycle

dNm: rate of increase in rotation speed of electric motor 6

Tm 1: the current output torque of the electric motor 6

Tm 2: predetermined output torque of the electric motor 6 in the next control cycle

dTm 1: the increase ratio of the output torque of the electric motor 6 (1 st upper limit ratio)

Setting the maximum increase rate of the output torque of the electric motor 6 to the 1 st upper limit rate is equivalent to the increase rate given to the supply power supplied to the electric motor 6 by the (formula 1).

Attention points related to the techniques described in the embodiments are described. The controller 10 limits the increase rate of the output torque of the electric motor 6 to the 1 st upper limit rate (or the 2 nd upper limit rate or the 3 rd upper limit rate) or less. In other words, the controller 10 changes the increase ratio according to the accelerator opening degree, and sets the maximum increase ratio to the 1 st upper limit ratio (or the 2 nd upper limit ratio or the 3 rd upper limit ratio). The rate of increase in the accelerator opening degree when small may be smaller than the 1 st upper limit rate (or the 2 nd upper limit rate or the 3 rd upper limit rate).

The controller 10 limits the increase rate of the output torque of the electric motor 6 to the 1 st upper limit rate dTm1 or less for a predetermined time P1 from the start of the fuel cell 3. In other words, the controller 10 sets the maximum increase rate of the output torque of the electric motor 6 during a predetermined time period P1 from the start of the fuel cell 3 to the 1 st upper limit rate dTm 1. The controller 10 limits the increase ratio after the prescribed time P1 has elapsed to 2 nd upper limit ratio dTm2 or less that is larger than the 1 st upper limit ratio dTm 1. In other words, the controller 10 sets the maximum increase ratio of the output torque after the predetermined time P1 has elapsed to the 2 nd upper limit ratio dTm2 that is larger than the 1 st upper limit ratio dTm 1.

In other words, the controller 10 controls as follows. During a predetermined time period P1 from the start of the fuel cell 3, the controller 10 sets the rate of increase in the output torque of the electric motor 6 when the accelerator opening degree is 100 [% ] to the 1 st upper limit rate dTm 1. At this time, when the accelerator opening is less than 100 [% ], the increase rate of the output torque becomes the 1 st upper limit rate dTm1 or less. After the predetermined time P1 has elapsed, the controller 10 sets the rate of increase of the output torque when the accelerator opening is 100 [% ] to the 2 nd upper limit ratio dTm2 that is greater than the 1 st upper limit ratio dTm 1. At this time, when the accelerator opening is less than 100 [% ], the increase rate of the output torque is equal to or less than the 2 nd upper limit rate dTm 2.

While specific examples of the present invention have been described above in detail, these are merely examples and do not limit the technical scope. The techniques described in the technical means include means obtained by variously changing and modifying the specific examples illustrated above. The technical elements described in the present specification or drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings can achieve a plurality of objects at the same time, and achieving one of the objects has technical usefulness itself.