JP2020172199A - Hybrid vehicle - Google Patents

Abstract

To provide a hybrid vehicle capable of obtaining smooth acceleration while securing power performance (accelerating force) even if a small drive battery is adopted.SOLUTION: An ECU controls a PCU so that drive power required for a drive motor is supplied by referring to a maximum use power map. In the maximum use power map, a total value of maximum generated power of a power generation motor and maximum output of a drive battery at the same engine speed is set as maximum use power, and the maximum user power is associated with each engine speed. As for a portion where the total value suddenly changes (a portion indicated by a broken line), the maximum use power is corrected so that the maximum use power does not exceed the total value of the maximum generated power of the power generation motor and the maximum output of the drive battery and the maximum use power is monotonously increased with respect to an increase in engine speed in the whole range of the engine speed.SELECTED DRAWING: Figure 3

Description

The present invention relates to a hybrid vehicle (HV).

Conventionally, a hybrid vehicle equipped with a drive motor which is a drive source for an engine and running is known. For example, in a series hybrid vehicle, the power of the engine is converted into electric power by a power generation motor, and the drive motor is driven by the electric power and the output of the battery, and the power of the drive motor is transmitted to the drive wheels (for example,). See Patent Document 1).

Japanese Unexamined Patent Publication No. 2004-343989

In a hybrid vehicle that uses a small (small capacity) battery from the viewpoint of cost reduction and compactness, the battery output and the power generated by the engine-driven power generation motor are used to the maximum in order to ensure the power performance during acceleration. It is conceivable to drive the drive motor.

However, it has been found that when the drive motor is driven by maximizing the battery output and the generated power during acceleration, the torque of the drive motor fluctuates and the acceleration may be jerky.

An object of the present invention is to provide a hybrid vehicle capable of obtaining smooth acceleration while ensuring power performance (acceleration force) even if a small drive battery is adopted.

In order to achieve the above object, in the hybrid vehicle according to the present invention, the power generation motor is driven by the power of the engine, the drive motor is driven by the power generated by the power generation motor and the output of the drive battery, and the power of the drive motor is powered. It is a series type hybrid vehicle that is transmitted to the drive wheels, and drives the drive motor based on the map storage means that stores the maximum power consumption map and at least the engine speed of the engine as an argument. The maximum power consumption map, including the drive control means for controlling, is a map that defines the relationship between the maximum power consumption obtained by adding the maximum output of the drive battery to the maximum power generation of the engine speed and the power generation motor. Therefore, the maximum power consumption is corrected from the map so that the maximum power consumption increases monotonically with the increase in the engine speed.

According to this configuration, the maximum power consumption that can be used by the drive motor is the sum of the maximum power generation of the power generation motor driven by the power of the engine and the maximum output of the drive battery. Therefore, by adding the generated power map that defines the relationship between the engine speed and the maximum generated power of the power generation motor and the battery output map that defines the relationship between the engine speed and the maximum output of the drive battery, the engine A map that defines the relationship between the number of revolutions and the maximum power consumption can be obtained.

However, the maximum generated power of the power generation motor decreases sharply at the start of cranking in which the power generation motor functions as a starter motor, and rises sharply at the end of cranking. Further, when the maximum output of the drive battery is temporarily increased when the hybrid vehicle is started, the maximum output of the drive battery is sharply reduced by the end of the increase. Therefore, in the map obtained by simply adding the generated power map and the battery output map, the maximum power consumption changes sharply at the time of cranking and at the end of the temporary increase in the maximum output of the drive battery. When the drive motor is driven with the maximum power consumption according to this map, the torque of the drive motor fluctuates due to the change in the maximum power consumption, and the acceleration becomes jerky when the hybrid vehicle starts.

Therefore, the maximum power consumption map is obtained by correcting the maximum power consumption so that the maximum power consumption increases monotonically with the increase in the engine speed from the map obtained by adding the generated power map and the battery output map. Based on the created maximum power consumption map, the drive motor is driven with a power in the range below the maximum power consumption. Therefore, even if a small drive battery is adopted, smooth acceleration can be obtained while ensuring power performance.

According to the present invention, even if a small drive battery is adopted, smooth acceleration can be obtained while ensuring power performance.

It is a block diagram which shows the structure of the hybrid vehicle which concerns on one Embodiment of this invention. It is a block diagram which graphically shows the structure for controlling the drive of a drive motor. A graph showing (a) the relationship between the engine speed and the maximum generated power of the power generation motor, (b) the relationship between the engine speed and the maximum output of the drive battery, and (c) the relationship between the engine speed and the maximum power consumption. Is.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Hybrid vehicle configuration>
FIG. 1 is a block diagram showing a configuration of a hybrid vehicle 1 according to an embodiment of the present invention.

The hybrid vehicle 1 adopts a series system, and is equipped with an engine (Eng) 2, a power generation motor (MG1) 3, and a drive motor (MG2) 4.

The engine 2 is, for example, a gasoline engine or a diesel engine. The crankshaft 11 of the engine 2 is provided so that the engine gear 12 rotates integrally with the crankshaft 11.

The power generation motor 3 includes, for example, a DC brushless motor. The rotating shaft 13 of the power generation motor 3 is provided so that the power generation motor gear 14 rotates integrally. The power generation motor gear 14 meshes with the engine gear 12. The power generation motor 3 is used as a starter motor for cranking the engine 2 when the engine 2 is stopped. After starting the engine 2, the power generation motor 3 functions as a generator that converts the power of the engine 2 into electric power.

The drive motor 4 is composed of, for example, a DC brushless motor larger than the power generation motor 3. The rotary shaft 15 of the drive motor 4 is provided so that the motor gear 16 rotates integrally with the rotary shaft 15.

The hybrid vehicle 1 includes a power transmission mechanism 17. The power transmission mechanism 17 includes a counter shaft 21, a counter gear 22, an output gear 23, and a differential gear 24. The counter shaft 21 is provided in parallel with the rotation shaft 15 of the drive motor 4. The counter gear 22 and the output gear 23 are provided so as to rotate integrally with the counter shaft 21. The counter gear 22 meshes with the motor gear 16. The output gear 23 meshes with the ring gear 25 of the differential gear 24.

The power of the drive motor 4 is transmitted to the ring gear 25 of the differential gear 24 via the motor gear 16, the counter gear 22, and the output gear 23, and is transmitted from the differential gear 24 to the drive wheels 27 of the hybrid vehicle 1 via the drive shaft 26. Be transmitted. As a result, the drive wheels 27 rotate, and the hybrid vehicle 1 travels forward or backward.

Further, the hybrid vehicle 1 is equipped with a PCU (Power Control Unit) 5, a driving battery 6 and a battery 7.

The PCU 5 is a unit for controlling the drive of the power generation motor 3 and the drive motor 4, and includes a first inverter (MG1 INV) 31, a second inverter (MG2 INV) 32, a boost converter (Bst CONV) 33, and a DC / DC. It includes a converter 34.

The drive battery 6 is an assembled battery used as a power source for the drive motor 4, and is, for example, a lithium ion battery (Li-ion BAT).

The battery 7 is a secondary battery used as a power source for an electric load other than the drive motor 4, and is, for example, a nickel hydrogen battery or a lithium ion battery. The battery 7 outputs 12 V (volt) DC power.

The three-phase AC power generated by the power generation motor 3 is converted into DC power by the first inverter 31. Then, the DC power output from the first inverter 31 is converted into three-phase AC power by the second inverter 32, and the three-phase AC power is supplied to the drive motor 4 to drive the drive motor 4. Further, the DC power output from the drive battery 6 is boosted by the boost converter 33, the boosted DC power is converted into three-phase AC power by the second inverter 32, and the three-phase AC power is converted to the drive motor 4. By being supplied, the drive motor 4 is driven. The DC power output from the first inverter 31 is stepped down by the boost converter 33, and the DC power after the step-down is supplied to the drive battery 6, so that the drive battery 6 is charged. The DC power after the step-down by the boost converter 33 is further stepped down by the DC / DC converter 34, and the DC power after the step-down is supplied to the battery 7 to charge the battery 7. Further, when the power generation motor 3 is used as a starter motor, the DC power output from the battery 7 is boosted by the DC / DC converter 34, further boosted by the boost converter 33, and then the boosted DC power is the first. It is converted into three-phase AC power by the inverter 31, and the three-phase AC power is supplied to the power generation motor 3.

The hybrid vehicle 1 is provided with an ECU (Electronic Control Unit) having a configuration including a microcomputer. Although FIG. 1 shows only one ECU 8 for controlling the engine 2 and the PCU 5, the hybrid vehicle 1 is equipped with a plurality of ECUs for controlling each part. A plurality of ECUs including the ECU 8 are connected so as to enable bidirectional communication by a CAN (Controller Area Network) communication protocol.

<Drive control of drive motor>
FIG. 2 is a block diagram illustrating a configuration for controlling the drive of the drive motor 4.

The maximum power consumption map is stored in the memory 41 built in the ECU 8. The ECU 8 takes as arguments the engine rotation speed, which is the rotation speed of the engine 2, the accelerator opening, which is the ratio of the operation amount to the maximum operation amount of the accelerator pedal, and the vehicle speed of the hybrid vehicle 1, and drives the ECU 8 with reference to the maximum power consumption map. The engine 2 and the PCU 5 are controlled so that the required driving power is supplied to the motor 4.

The engine rotation speed can be obtained from the detection signal of the engine rotation sensor provided with an engine rotation sensor that outputs a pulse signal synchronized with the rotation of the crankshaft 11 of the engine 2 as a detection signal. The accelerator opening degree can be obtained from the detection signal of the accelerator sensor provided with an accelerator sensor that outputs a detection signal according to the operation amount of the accelerator pedal (not shown) operated by the driver. The vehicle speed can be obtained from the detection signal of the vehicle speed sensor provided with a vehicle speed sensor that outputs a pulse signal synchronized with the rotation of the rotating body that rotates with the traveling of the hybrid vehicle 1 as a detection signal.

<Maximum power consumption map>
FIG. 3 shows (a) the relationship between the engine speed and the maximum generated power of the power generation motor 3, (b) the relationship between the engine speed and the maximum output of the drive battery 6, and (c) the engine speed and the maximum power consumption. It is a graph which shows the relationship with.

The maximum power consumption that can be used by the drive motor 4 is the sum of the maximum power generation power of the power generation motor 3 driven by the power of the engine 2 and the maximum output of the drive battery 6.

As shown in FIG. 3A, the maximum generated power of the power generation motor 3 sharply decreases at the start of cranking in which the power generation motor 3 functions as a starter motor, and rises sharply at the end of cranking.

Further, in the hybrid vehicle 1, the maximum output of the drive battery 6 is temporarily increased at the time of starting. For example, the maximum output of the drive battery 6 is increased by a certain amount until 1 second elapses from the start, and the maximum output of the drive battery 6 is decreased to a constant normal output 1 second after the start. .. Therefore, as shown in FIG. 3B, the maximum output of the drive battery 6 suddenly drops due to the end of the temporary increase in the maximum output of the drive battery 6.

Therefore, when the maximum generated power of the power generation motor 3 and the maximum output of the drive battery 6 at the same engine speed are added up and the total value is associated with each engine speed and mapped, FIG. 3 (c) As shown by the broken line in), the total value changes sharply at the time of cranking and at the end of the temporary increase in the maximum output of the drive battery 6. Therefore, when the drive power supplied to the drive motor 4 is set to the total value and the drive of the drive motor 4 is controlled according to the map of the characteristics shown by the broken line in FIG. 3 (c), when the drive motor 4 is suddenly changed at the time of total change. The torque of the drive motor 4 fluctuates, and the acceleration of the hybrid vehicle 1 becomes jerky.

Therefore, in the maximum power consumption map, as shown by the solid line in FIG. 3C, the total value of the maximum power generation of the power generation motor 3 and the maximum output of the drive battery 6 at the same engine speed is the maximum use. It is set to electric power, and its maximum electric power is associated with each engine speed. The part where the total value suddenly changes (the part shown by the broken line in FIG. 3B) does not exceed the total value of the maximum generated power of the power generation motor 3 and the maximum output of the drive battery 6, and the engine rotation speed. The maximum power consumption is corrected (set) so that the maximum power consumption increases monotonically with the increase in engine speed in the entire range of.

<Effect>
The ECU 8 acquires the maximum power consumption according to the engine rotation speed from the maximum power consumption map, and drives the drive motor 4 so that the torque of the drive motor 4 becomes appropriate based on the accelerator opening and the vehicle speed. The drive motor 4 is driven with the power set to be equal to or lower than the maximum power consumption. As a result, even if a small (small capacity) assembled battery is used as the drive battery 6, smooth acceleration can be obtained while ensuring power performance. Further, by suppressing the torque of the drive motor 4, it is possible to suppress the occurrence of tire slip of the drive wheels 27.

<Modification example>
Although one embodiment of the present invention has been described above, the present invention can also be implemented in other embodiments.

For example, the present invention is particularly effective in a configuration in which a small assembled battery (battery) is mounted as a driving battery 6, but of course, it is applied to a configuration in which a large (large capacity) assembled battery is mounted as a driving battery 6. May be done.

In addition, various design changes can be made to the above-mentioned configuration within the scope of the matters described in the claims.

1: Hybrid vehicle 2: Engine 3: Power generation motor 4: Drive motor 5: PCU (drive control means)
6: Drive battery 8: ECU (drive control means)
41: Memory (map storage means)

Claims (1)

A series-type hybrid vehicle in which a power generation motor is driven by the power of an engine, the drive motor is driven by the power generated by the power generation motor and the output of the drive battery, and the power of the drive motor is transmitted to the drive wheels. ,
A map storage means for storing the maximum power consumption map and
It includes a drive control means for controlling the drive of the drive motor based on the maximum power consumption map, with at least the engine speed of the engine as an argument.
The maximum power consumption map is a map that defines the relationship between the engine speed and the maximum power consumption obtained by adding the maximum output of the drive battery to the maximum power generation power of the power generation motor, and is from the map. A hybrid vehicle, which is a map in which the maximum power consumption is corrected so that the maximum power consumption increases monotonically with respect to an increase in the engine speed.

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