JP6547957B2 - Air compressor device - Google Patents

Description

  The present invention relates to an air compressor device.

  Conventionally, there has been proposed a fuel cell vehicle equipped with a fuel cell (hereinafter also referred to as FC) which generates electric power by causing a chemical reaction between hydrogen as a fuel gas and oxygen in air as an oxidant gas as a power supply device.

  Air supplied to the fuel cell is taken in from the outside air and pumped by an on-board air compressor (hereinafter also referred to as ACP). The amount of air supplied to the fuel cell is adjusted by controlling the number of revolutions of a motor incorporated as a drive source of the air compressor according to the operating state of the fuel cell.

  By the way, the fuel cell and the air compressor are usually separated, and the reaction gas (air) is compressed between the air compressor and the fuel cell even if the rotational speed of the air compressor is increased with the increase of the required power generation amount. The reaction gas is delayed until it reaches the fuel cell from the air compressor. A technology for controlling the generated current in consideration of this delay is proposed in Patent Document 1 below.

JP, 2009-277456, A

  When the difference between the required number of revolutions of the air compressor and the present number of revolutions is equal to or more than a predetermined value in order to eliminate the air supply delay described above in consideration of drivability (in other words, when the revolution number command suddenly changes) In addition, it is conceivable to set the degree of change in the rotational speed of the air compressor to the maximum value of the performance (for example, control in which the air compressor responds at the fastest). However, for example, if the air compressor is operated at the maximum value of the performance against the change of the rotation speed command even at the slow load after the intermittent operation, the power consumption in the air compressor becomes large, and the fuel efficiency is deteriorated. .

  The present invention has been made in view of such problems, and an object thereof is to provide an air compressor device that can achieve both drivability and fuel consumption.

  In order to solve the above problems, an air compressor device according to the present invention comprises a required number of revolutions of an air compressor for supplying an air supply amount required to output a required power from the fuel cell and a current speed of the air compressor. The air compressor further includes a control unit that controls the torque command value and the number of revolutions of the air compressor based on the difference with the number of revolutions and the required power value for the fuel cell. When the power requirement value is equal to or greater than a predetermined value, the rotational speed of the air compressor is increased based on the first acceleration torque, and the difference is equal to or greater than the predetermined value, and the power requirement value is less than the predetermined value. The rotational speed of the air compressor is increased by a second acceleration torque that is smaller than the first acceleration torque.

  According to this configuration, the fuel efficiency is improved when the required torque is small, considering not only the difference between the required number of revolutions of the air compressor and the present number of revolutions of the air compressor but also the magnitude of the required power value for the fuel cell. Limit the acceleration torque to delay reaching the required speed. As described above, when the power requirement value for the fuel cell is equal to or less than the predetermined value (for example, during slow load traveling after intermittent operation), the fastest response of the air compressor is not necessary. By doing so, the power consumption of the air compressor is reduced. Thereby, coexistence of fuel consumption and drivability can be aimed at. Note that intermittent operation refers to an operation that temporarily suspends power generation in the fuel cell and supplies power from the secondary battery to the load when the output required of the fuel cell system is less than or equal to a predetermined threshold. .

  According to the present invention, it is possible to provide an air compressor device that can achieve both drivability and fuel consumption.

It is an explanatory view showing an example of a fuel cell and an oxidation gas supply discharge system. It is a graph which shows the rotation speed of an air compressor, the torque command of an air compressor, and the loss of an air compressor when rotation speed instructions increase at the time of intermittent operation start. It is a graph which shows the loss characteristic of an air compressor.

  Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. The following description of the preferred embodiments is merely an example, and is not intended to limit the present invention, its applications, or its applications.

  FIG. 1 is an explanatory view showing an example of a fuel cell and an oxidizing gas supply and discharge system. The fuel cell system includes a fuel gas supply / discharge system and a cooling system in addition to the oxidative gas supply / discharge system shown in FIG. 1 and is mounted on a fuel cell vehicle (not shown). Only the fuel gas supply and discharge system and the cooling system will not be described.

  The oxidizing gas supply and discharge system 300 includes an oxidant gas supply pipe 310, an oxidant exhaust gas discharge pipe 320, a bypass pipe 330, a diverting valve 340, a pressure regulating valve 350, an air compressor 360, and a rotation number sensor 370. Equipped with

  The oxidant gas supply pipe 310 is a pipe for supplying the oxidant gas to the fuel cell 100, and the oxidant exhaust gas discharge pipe 320 is a pipe for discharging the oxidant exhaust gas from the fuel cell 100. The bypass pipe 330 connects the oxidant gas supply pipe 310 and the oxidant exhaust gas discharge pipe 320. A dividing valve 340 is provided at the connection between the oxidant gas supply pipe 310 and the bypass pipe 330. The diverting valve 340 diverts the oxidant gas into the oxidant gas supplied to the fuel cell 100 and the oxidant gas flowing to the bypass pipe 330. The pressure regulator valve 350 regulates the pressure of the oxidant gas in the fuel cell 100. In the present embodiment, air is used as the oxidant gas. The air compressor 360 compresses the air and supplies the air as the oxidant gas to the fuel cell 100 through the oxidant gas supply pipe 310. For example, the control unit 200 calculates a rotation speed command value of the air compressor 360, or calculates a torque command value of the air compressor 360. Details of an operation example of the control unit 200 will be described later. The air compressor according to the present invention includes an air compressor 360 and a control unit 200.

  Subsequently, an operation example of the air compressor 360 by the control unit 200 will be described with reference to FIG. FIG. 2 is a time chart for explaining an operation example of the air compressor 360. As shown in FIG.

  For example, at the time of intermittent operation (time t1), when the accelerator pedal (not shown) is depressed, the required power to the fuel cell 100 is increased according to the depression amount (accelerator opening degree).

  The control unit 200 calculates the flow rate of air to be supplied to the fuel cell 100 in order to output the required power from the fuel cell 100, and the rotational speed command value of the air compressor 360 necessary to supply the air of this flow rate calculate. Then, control unit 200 calculates a torque command value (acceleration torque) for air compressor 360 using the rotation speed command value for air compressor 360 and the current rotation speed acquired by rotation speed sensor 370.

  By the way, when increasing the torque command value according to the increase of the required power based on the accelerator opening degree and the increase of the rotation speed command value, the air compressor 360 is made to respond at the fastest to secure the responsiveness of the fuel cell 100. It is necessary to accelerate the air supply to the fuel cell 100. That is, it is necessary to control the air compressor 360 so that the air is supplied to the fuel cell 100 with good responsiveness in accordance with the change of the rotational speed command value.

However, if control such that the air compressor 360 responds at the fastest (control operating at the maximum value of the performance) is performed in this way, even in a state where the power demand for the fuel cell 100 is small, for example, after intermittent operation at low speed. As a result, the air compressor 360 responds at the highest speed, and the loss of power consumption (ACP loss) in the air compressor increases. For example, as shown in FIG. 2, after intermittent operation, when control is performed to respond the air compressor 360 at the fastest speed so as to reach a predetermined rotation speed at time t2 (rotation speed R _C shown by broken line in FIG. The torque command T _c ) and the ACP loss at time t1 to t2 become large (E _c indicated by a broken line in FIG. 2). As shown in FIG. 3 (loss characteristics of the air compressor), the loss of power consumption in the air compressor 360 increases as the rotation speed and torque of the air compressor 360 increase.

  Therefore, in the present embodiment, when the power demand for the fuel cell 100 is equal to or less than a predetermined value, the acceleration torque of the air compressor 360 is controlled so as to give priority to fuel consumption over responsiveness.

Specifically, the control unit 200 controls the air compressor 360 as follows. That is, the difference between the required number of revolutions of the air compressor 360 for supplying the amount of air supply necessary to output the required power from the fuel cell 100 and the present number of revolutions of the air compressor 360 is equal to or greater than a predetermined value. When the power requirement value for the fuel cell 100 is equal to or greater than the predetermined value, the control unit 200 increases the rotational speed of the air compressor 360 based on the first acceleration torque. Furthermore, the difference between the required number of revolutions of the air compressor 360 for supplying the amount of air supply required to output the required power based on the accelerator opening from the fuel cell 100 and the present number of revolutions of the air compressor 360 are predetermined. If the power demand value for the fuel cell 100 is less than the predetermined value, the air compressor is selected based on the second acceleration torque (torque command T _P indicated by a solid line in FIG. 2) lower than the first acceleration torque. Increase the number of revolutions of 360.

As described above, when the power requirement value for the fuel cell 100 is less than the predetermined value, the fuel efficiency is improved to delay reaching the predetermined number of rotations (as indicated by the solid line R _P in FIG. 2). to, to reach a predetermined rotational speed at time t3), it is possible to suppress the ACP loss (E _P indicated by a solid line in FIG. 2). As a result, the fuel efficiency can be improved while securing the necessary power generation response speed of the fuel cell 100, in other words, both drivability and fuel efficiency can be achieved.

  Further, in the present embodiment, the acceleration torque may be limited when the rotation speed command suddenly changes due to applications other than power generation such as air blow. Specifically, in applications other than power generation such as air blow, when the rotation speed command to the air compressor 360 suddenly changes, the control unit 200 controls the air compressor 360 based on the second acceleration torque lower than the first acceleration torque described above. Increase the speed of Since the fastest response of the air compressor 360 is not required for functions other than power generation such as air blow, fuel efficiency can be improved while maintaining functionality by controlling acceleration torque also in such applications. .

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. That is, those to which those skilled in the art appropriately modify the design of these specific examples are also included in the scope of the present invention as long as they have the features of the present invention. The elements included in each of the specific examples described above and their arrangements, materials, conditions, shapes, sizes, and the like are not limited to those illustrated, and can be changed as appropriate.

100: Fuel cell 200: Control unit 300: Oxidizing gas supply and discharge system 310: Oxidizing gas supply pipe 320: Oxidizing gas exhaust pipe 360: Air compressor 370: Rotational speed sensor

Claims (1)

An air compressor used in a fuel cell system, comprising:
The difference between the required number of revolutions of the air compressor for supplying the required amount of air supply to output the required power from the fuel cell and the present number of revolutions of the air compressor, and the operating state of the fuel cell And a controller configured to control the torque command value and the number of revolutions of the air compressor based on the determination result of whether or not
The control unit
The rotation number of the air compressor is increased based on the first acceleration torque when it is determined that the difference is equal to or more than a predetermined value and the operating state of the fuel cell is not intermittent operation .
When it is determined that the difference is equal to or more than a predetermined value and the operation state of the fuel cell is after intermittent operation, the number of revolutions of the air compressor is increased by a second acceleration torque smaller than the first acceleration torque. Air compressor device, which delays the time to reach the required rotational speed .