JP2022169023A - Control device - Google Patents

Abstract

To provide a control device which can improve the fuel consumption of a hybrid vehicle.SOLUTION: An engine is basically controlled to operate at an operation point on an optimum fuel consumption line. When the operation point of the engine according to the power generation request power is not included in a highest thermal efficiency region, a direction in which the total of the engine loss and the electric loss of each electric unit becomes low is read such that the electric loss does not exceed the engine loss on the basis of an engine output-loss difference relation and an engine output-electric loss relation, and the operation point (output) of the engine is moved in the direction.SELECTED DRAWING: Figure 4

Description

The present invention relates to a control device used in a hybrid vehicle (HV).

In a series-type hybrid vehicle, engine power is converted into electric power by a generator motor (generator), a drive motor is driven by the electric power, and power of the drive motor is transmitted to drive wheels. Since the engine is separated from the drive wheels, the engine speed and engine torque can be freely controlled.

FIG. 5 is a diagram showing the optimal fuel consumption line and maximum thermal efficiency region of the engine.

The optimum fuel consumption line is a characteristic line representing a set of operating points (engine speed and engine torque) at which fuel consumption is minimized with respect to the shaft output of the engine. The highest thermal efficiency region is the region where the highest thermal efficiency of the engine is achieved.

In a series-type hybrid vehicle, depending on the driving situation, there is an EV (Electric Vehicle) drive mode in which the drive motor is driven only by the output of the battery, and a generator motor that uses the power of the engine to generate power. and a hybrid drive mode in which the driving motor is driven by the power combined with the output of the battery.

In the hybrid drive mode, the required drive power required for running and the required power generation, which is the amount of power generation required by the generator motor, are determined. As realized, the drive motor and generator motor are controlled. The requested power generation includes the power consumed by the drive motor, that is, the requested drive power, and the state of charge (SOC), which indicates the state of charge of the battery (the ratio of the remaining charge to the charge capacity), within the usage range. The required battery power, which is the charge/discharge amount, is included.

At this time, the engine is controlled to operate at an operating point on the optimum fuel efficiency line. If the engine operating point corresponding to the requested power generation falls within a region higher than the maximum thermal efficiency region due to the high power generation demand, the engine speed is lowered so that the engine operating point moves to the maximum thermal efficiency region. (Engine output is reduced), and the battery outputs the insufficient power. In addition, when the operating point of the engine corresponding to the requested power generation is lower than the maximum thermal efficiency region because the required power generation is low, the engine speed is raised (engine output is raised), and the battery is charged with the surplus power output from the generator motor. As a result, the engine can always be operated in the highest thermal efficiency region.

JP 2013-189113 A

However, by moving the operating point of the engine from the operating point corresponding to the power required for power generation to the operating point included in the highest thermal efficiency region, the loss rather increases, the fuel consumption of the engine increases, and the fuel efficiency deteriorates. It turns out that there is a case.

SUMMARY OF THE INVENTION An object of the present invention is to provide a control device capable of improving the fuel efficiency of a hybrid vehicle.

In order to achieve the above object, the control device according to the present invention includes a battery that charges and discharges electric power, an engine that outputs power, a generator motor that generates power using the power of the engine, and a drive motor that generates power for running. is a control device used in a hybrid vehicle equipped with an engine output and an engine loss that occurs when the engine is operated at a high thermal efficiency operating point where the thermal efficiency is a predetermined value or higher, and a low heat that results in a lower thermal efficiency than that. The loss difference from the engine loss that occurs when operating at the efficiency operating point, the engine output - loss difference relationship, and the engine output and the electrical loss that occurs when the loss difference is replaced with the electrical output of the battery. It has an engine output-electrical loss relationship, and changes the output of the engine based on the engine output-loss differential relationship and the engine output-electrical loss relationship.

According to this configuration, the engine output is changed based on the engine output-loss difference relationship and the engine output-electrical loss relationship.

For example, the engine power-loss differential relationship and the engine power-electrical loss relationship are compared and the operating point of the engine is moved so that the electrical losses do not exceed the differential losses. As a result, the loss can be reduced and the fuel efficiency of the hybrid vehicle can be improved.
The engine output-loss difference relationship is the relationship between the engine output and the loss difference between the engine loss that occurs when the engine is operated at the highest thermal efficiency operating point and the engine loss that occurs when the engine is operated at other thermal efficiency operating points. may be

According to the present invention, fuel efficiency of a hybrid vehicle can be improved.

1 is a block diagram showing the configuration of a main part of a hybrid vehicle to which a control device according to an embodiment of the invention is applied; FIG. FIG. 5 is a diagram showing the relationship between the engine output and the loss difference between the engine loss that occurs when the engine is operated at the highest thermal efficiency operating point and the engine loss that occurs when the engine is operated at other thermal efficiency operating points. 3 is a diagram showing the relationship between battery output and electrical loss when the loss difference shown in FIG. 2 is replaced with battery output. FIG. FIG. 4 is a diagram showing the relationship between engine output and engine loss difference and the relationship between engine output and electrical loss; FIG. 4 is a diagram showing an optimum fuel consumption line and a maximum thermal efficiency region of an engine;

BEST MODE FOR CARRYING OUT THE INVENTION Below, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Main configuration of hybrid vehicle>
FIG. 1 is a block diagram showing the configuration of main parts of a hybrid vehicle 1 to which a control device according to one embodiment of the invention is applied.

The hybrid vehicle 1 is a vehicle equipped with a series hybrid system. A hybrid vehicle 1 is equipped with an engine 2, a generator motor (MG1) 3, and a drive motor (MG2) 4. As shown in FIG.

The engine 2 is, for example, a 3-cylinder 4-stroke reciprocating engine. The engine 2 is provided with an electronic throttle valve for adjusting the amount of intake air into the combustion chamber, an injector (fuel injection device) for injecting fuel into the intake air, and a spark plug for generating electrical discharge in the combustion chamber. .

The generator motor 3 and the drive motor 4 are, for example, permanent magnet synchronous motors (PMSM).

The generator motor 3 is directly connected to the engine 2 as a generator motor that generates power using the power of the engine 2 , for example, by providing the rotary shaft thereof to rotate integrally with the crankshaft of the engine 2 .

The drive motor 4 is a drive motor that generates power for running the hybrid vehicle 1 , and has a rotation shaft connected to a drive system for running the hybrid vehicle 1 . The traveling drive system includes, for example, a differential gear 5, and a ring gear 6 of the differential gear 5 is meshed with a drive motor gear 7 provided to rotate integrally with the rotation shaft of the drive motor 4. . Power generated by the drive motor 4 is transmitted from the drive motor gear 7 to the ring gear 6 of the differential gear 5 , and from the differential gear 5 to the left and right drive wheels 9 via the left and right drive shafts 8 . As a result, the drive wheels 9 rotate and the hybrid vehicle 1 travels forward or backward.

Also, the hybrid vehicle 1 is equipped with a battery (BAT) 11 and a PCU (Power Control Unit) 12 .

The battery 11 is an assembled battery in which a plurality of secondary batteries are combined. A secondary battery is, for example, a lithium ion battery. The battery 11 outputs DC power of about 200 to 150 V (volt), for example.

The PCU 12 is a unit for controlling the driving of the generator motor 3 and the drive motor 4, and includes inverters 13 and 14, a converter (CONV) 15 and an MGECU 16.

The inverter (INV1) 13 is a three-phase voltage source inverter that drives the generator motor 3, and includes a series circuit of two IGBTs (Insulated Gate Bipolar Transistors) for each of U-phase, V-phase and W-phase. They are provided corresponding to the phases, and have a configuration in which these series circuits are connected in parallel between the plus wiring and the minus wiring. The inverter 13 converts the DC power into AC power and supplies the AC power to the generator motor 3 during power running of the generator motor 3 . In addition, the inverter 13 converts AC power generated by the generator motor 3 into DC power when the generator motor 3 is in regenerative operation (power generation operation).

The inverter (INV2) 14 is a three-phase voltage source inverter that drives the drive motor 4. Similar to the inverter 13, the inverter (INV2) 14 is a series circuit of two IGBTs corresponding to each of the U-phase, V-phase and W-phase. and the series circuits are connected in parallel between the plus wiring and the minus wiring. The inverter 14 converts the DC power into AC power and supplies the AC power to the drive motor 4 during power running of the drive motor 4 . Further, the inverter 14 converts AC power generated by the drive motor 4 into DC power when the drive motor 4 is in regenerative operation (power generation operation).

Converter 15 boosts the DC power output from battery 11 and supplies it to inverters 13 and 14 when generator motor 3 and drive motor 4 are powered. Further, during regenerative operation of the generator motor 3 and the drive motor 4 , the DC power output from the inverters 13 and 14 is stepped down and supplied to the battery 11 .

The hybrid vehicle 1 is equipped with a plurality of ECUs (Electronic Control Units), and the MGECU 16 is one of the plurality of ECUs. Each ECU has a microcomputer (microcontroller), and the microcomputer contains, for example, a CPU, nonvolatile memory such as flash memory, and volatile memory such as DRAM (Dynamic Random Access Memory). A plurality of ECUs are connected so as to be capable of two-way communication using CAN (Controller Area Network) communication protocol.

The HVECU 17 is included in the plurality of ECUs. The HVECU 17 is a unit that comprehensively controls the hybrid system including the engine 2 , the generator motor 3 and the drive motor 4 . In controlling the generator motor 3 and the drive motor 4, a motor control command is transmitted from the HVECU 17 to the MGECU 16, and the MGECU 16 controls the operations of the inverters 13, 14 and the converter 15 according to the motor control command.

In the hybrid vehicle 1, when the engine 2 is started, electric power is supplied from the battery 11 to the generator motor 3, and the generator motor 3 is powered, whereby the engine 2 is motored (cranked) by the generator motor 3. . When the ignition plug of the engine 2 is sparked while the number of rotations of the engine 2 is increased to the number of rotations required for firing by motoring, the engine 2 fires.

When the hybrid vehicle 1 is running, the drive motor 4 is power-running, and the drive motor 4 generates power. When the engine 2 is stopped and the generator motor 3 does not generate power, the drive motor 4 is driven by the output of the battery 11, so that the hybrid vehicle 1 travels as an electric vehicle (EV). Further, while the engine 2 is in an operating state (firing) and the generator motor 3 is in a power generation operation (regenerative operation), the drive motor is powered by the combined power of the output (generated power) of the generator motor 3 and the output of the battery 11. 4 is driven, the hybrid vehicle 1 performs HV running.

During deceleration of the hybrid vehicle 1, the drive motor 4 is regeneratively operated, and the power transmitted from the drive wheels to the drive motor 4 is converted into AC power. At this time, the drive motor 4 acts as a resistance of the traveling drive system, and the resistance acts as a braking force (regenerative braking force) for braking the hybrid vehicle 1 . Also at this time, the battery 11 is charged by supplying the electric power generated by the drive motor 4 to the battery 11 .

<Moving the operating point of the engine>
FIG. 2 shows the relationship between the engine output and the loss difference between the engine loss that occurs when the engine 2 is operated at the highest thermal efficiency operating point in the entire power range and the engine loss that occurs when operating at other thermal efficiency operating points. FIG. 4 is a diagram showing;

In FIG. 2, the thick line indicates the maximum efficiency point loss, which is the engine loss that occurs in the engine 2 when the engine 2 operates in the maximum thermal efficiency region over the entire power range. A thin line indicates the engine loss that occurs in the engine 2 when the engine 2 operates in a region other than the maximum thermal efficiency region in the entire power range. The engine loss when the engine 2 operates in a region other than the maximum thermal efficiency region is greater than the maximum efficiency point loss in the entire power range of the engine 2 .

FIG. 3 is a diagram showing the relationship between battery output and electrical loss when the loss difference shown in FIG. 2 is replaced with battery output.

The relationships shown in FIG. 3 are created from the relationships shown in FIG. That is, when a loss difference (engine loss difference), which is the difference between the engine loss and the maximum efficiency point loss, is obtained and the battery output of the battery 11 is substituted for the loss difference, the battery 11, the inverters 13 and 14, and the converter The sum of the electrical losses incurred in each electrical unit including 15 is determined. By associating the battery output and the electrical loss of the battery 11, the relationship between the battery output and the electrical loss shown in FIG. 3 is created.

FIG. 4 is a diagram showing the relationship between engine output and engine loss difference and the relationship between engine output and electrical loss.

The engine output - loss difference relationship between the engine output and the engine loss difference is obtained by obtaining the loss difference, which is the difference between the engine loss and the maximum efficiency point loss for each engine output, and comparing the obtained loss difference with each engine output. It is created by being associated.

The engine output-electrical loss relationship between engine output and electrical loss is created by converting the relationship between battery output and electrical loss shown in FIG. 3 into the relationship between engine output and electrical loss.

The engine output-loss differential relationship and the engine output-electrical loss relationship are stored in the non-volatile memory of the HVECU 17. FIG.

In a mode (hybrid drive mode) in which the hybrid vehicle 1 runs in an HV mode, a required drive power required for running and a required power generation amount, which is an amount of power generation required for the generator motor 3, are obtained. The generator motor 3 and the drive motor 4 are controlled so that the requested power generation is achieved by the drive motor and the generator motor 3, respectively. The requested power generation includes the electric power consumed by the drive motor 4, that is, the requested drive power, and the requested battery power, which is the charge/discharge amount for keeping the state of charge (SOC) indicating the state of charge of the battery 11 within the usable range. and are included.

At this time, the engine 2 is controlled to operate at an operating point on the optimum fuel efficiency line. When the operating point of the engine 2 corresponding to the requested power generation is not included in the maximum thermal efficiency region (see FIG. 5), the HVECU 17 determines the operation of the engine 2 based on the engine output-loss difference relationship and the engine output-electrical loss relationship. A point (output) is moved.

Specifically, in areas A and B where the slope of the engine output-loss differential relationship is greater than the slope of the engine output-electrical loss relationship, the electrical loss may fall below the engine loss when the engine output is reduced. , the slope of the engine output-loss differential relationship is smaller than the slope of the engine output-electrical loss relationship, the electrical loss may exceed the engine loss when the output of the battery 11 is increased. In the regions A and B, the direction in which the total of the engine loss and the electrical loss of each electrical unit is low is read so that the electrical loss does not exceed the engine loss, and the operating point (output) of the engine 2 is set in that direction. be moved.

<effect>
As described above, by moving the operating point of the engine 2, the loss in the hybrid system as a whole can be reduced, and the fuel efficiency of the hybrid vehicle 1 can be improved.

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

For example, the generator motor 3 may not be directly connected to the engine 2, and the rotating shaft of the generator motor 3 and the crankshaft of the engine 2 may be connected via gears.

Further, in the above-described embodiment, the hybrid vehicle 1 equipped with a series hybrid system is taken up as an example of an electric vehicle, but the electric vehicle is a hybrid vehicle equipped with a hybrid system other than the series system. good too.

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

1: hybrid vehicle 2: engine 3: generator motor 4: drive motor 11: battery 17: HVECU (control device)

Claims (1)

A control device for use in a hybrid vehicle equipped with a battery that charges and discharges electric power, an engine that outputs power, a generator motor that generates power using the power of the engine, and a drive motor that generates power for running. ,
The loss of the output of the engine and the engine loss that occurs when the engine is operated at a high thermal efficiency operating point where the thermal efficiency is equal to or higher than a predetermined value, and the engine loss that occurs when the engine is operated at a low thermal efficiency operating point where the thermal efficiency is lower than that. the difference and the engine output-loss difference relationship of, and
Having an engine output-electrical loss relationship between the engine output and the electrical loss that occurs when the loss difference is replaced with the electrical output of the battery,
A control device that changes the output of the engine based on the engine output-loss difference relationship and the engine output-electrical loss relationship.

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