JP2023053688A - Control device - Google Patents

Abstract

To operate an internal combustion engine in an output region having favorable heat efficiency if possible, and to improve the practical fuel economy performance of a hybrid vehicle.SOLUTION: A control device of a hybrid vehicle charges power which is generated by driving a generator by an internal combustion engine to a power accumulator, or controls the hybrid vehicle which travels by supplying the power to an electric motor and driving drive wheels by the electric motor. When an output which is required to the electric motor for the traveling of the vehicle is in a prescribed range in which the heat efficiency of the internal combustion engine is considered to be favorable, or has a magnitude which is equal to or lower than the range, the control device controls an output of the internal combustion engine to a magnitude within the prescribed range, generates the power by the generator, and charges a difference between the power which is supplied to the electric motor from the generator, and a required output to the power accumulator, or supplies it from the power accumulator.SELECTED DRAWING: Figure 4

Description

The present invention relates to control of an internal combustion engine and a rotating electrical machine mounted on a hybrid vehicle.

2. Description of the Related Art In recent years, hybrid vehicles equipped with two power sources, an internal combustion engine and an electric motor, are gaining popularity. A series-type hybrid vehicle (see, for example, the following patent document) generates power by driving a motor generator for power generation with an internal combustion engine, and stores the generated power in a power storage device, such as a lithium ion secondary battery or a nickel metal hydride secondary battery. It is stored in a battery and/or a capacitor, etc., and supplied to a motor-generator for running. Then, the driving wheels of the vehicle are rotated by the motor generator for traveling to travel.

Not only the motor-generator for power generation but also the motor-generator for traveling can generate power by regenerative braking, and the generated power can be stored in the power storage device. When electric charge is already stored up to the capacity of the power storage device, the electric power obtained by regenerative braking is intentionally supplied to the motor generator for power generation, and this is operated as an electric motor to perform motoring to rotationally drive the internal combustion engine. This consumes excess power.

In a series-type hybrid vehicle, the motor generator for power generation serves to motor (crank) the internal combustion engine in preparation for starting the stopped internal combustion engine. concurrently. At that time, power is supplied from the power storage device.

In a hybrid vehicle, the electric charge stored in the power storage device is consumed by the motor-generator for running to output rotational driving force to run the vehicle without performing firing for operating the internal combustion engine by burning fuel in the cylinder. is possible. Therefore, even during operation of the vehicle, the state in which the rotation of the internal combustion engine is stopped may continue.

When the amount of electric charge stored in the power storage device decreases, or when the required output of the traction motor-generator is large, the internal combustion engine is started, fuel is supplied to the cylinders, and the fuel is combusted, and the rotational driving force output by the internal combustion engine. to drive the power generation motor generator to generate power to charge the power storage device or increase the electric power supplied to the running motor generator.

JP 2020-156134 A

2. Description of the Related Art The amount of output required of a motor-generator for running, which is an electric motor, for running a vehicle depends on the amount of depression of an accelerator pedal operated by the driver of the vehicle. Then, the magnitude of the output during firing of the internal combustion engine that drives the motor-generator for power generation, which is a power generator, is determined according to the current amount of power stored in the power storage device in addition to the above-described required output.

In the conventional control of a hybrid vehicle, when the required output of the driving motor generator is not large, the internal combustion engine is fired at a low output to generate power, and the shortage of electric power is supplied from the power storage device to the driving motor generator. or to charge the power storage device with the surplus power.

However, in such low-power operation, the thermal efficiency of the internal combustion engine (or the efficiency of the entire system including the PCU (Power Control Unit)) falls below the best possible value. If the frequency and duration of low-power operation increases, there is concern that the fuel efficiency of the vehicle will deteriorate. In other words, it can be said that there is still room for further improvement in fuel efficiency.

SUMMARY OF THE INVENTION It is an object of the present invention to operate an internal combustion engine in an output range in which thermal efficiency is as good as possible, thereby improving the practical fuel consumption performance of a hybrid vehicle.

In the present invention, the internal combustion engine drives a generator to generate electric power, which is charged in a power storage device or supplied to an electric motor to control a hybrid vehicle that drives drive wheels by the electric motor. When the output required of the electric motor for running the engine is within or below a predetermined range in which the thermal efficiency of the internal combustion engine is considered to be good, the output of the internal combustion engine is controlled within the predetermined range. A control device for a hybrid vehicle is configured in which a power storage device is charged with the difference between the power supplied from the generator to the electric motor and the required output, or power is supplied from the power storage device.

In order to control the output of the internal combustion engine within the predetermined range, it is preferable to increase the output of the internal combustion engine as the amount of electricity stored in the current storage device decreases.

According to the present invention, it is possible to operate the internal combustion engine in an output range in which the thermal efficiency is as good as possible, thereby improving the practical fuel consumption performance of the hybrid vehicle.

1 is a diagram showing a schematic configuration of a series hybrid vehicle and a control device according to an embodiment of the present invention; FIG. The figure which shows the outline|summary of the internal combustion engine mounted in the hybrid vehicle of the same embodiment. FIG. 4 is a flow diagram relating to control executed by the control device of the embodiment according to a program; The figure explaining the content of control by the control apparatus of the same embodiment. The figure explaining the content of control by the control apparatus of the same embodiment. The figure explaining the content of control by the control apparatus of the same embodiment. The figure explaining the content of control by the control apparatus of the same embodiment.

One embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of main systems of a vehicle in this embodiment. The vehicle of this embodiment is a hybrid vehicle equipped with two types of power sources. An internal combustion engine 1, a power generating motor generator 2 that is a rotating electrical machine that generates power by being driven by the internal combustion engine 1, a power storage device 3 that stores the electric power generated by the power generating motor generator 2, the power generating motor generator 2, and/or A running motor generator 4, which is a rotary electric machine that receives power supply from the power storage device 3 and drives drive wheels 62 of the vehicle, is provided.

This hybrid vehicle is a series hybrid electric vehicle that uses the internal combustion engine 1 only for power generation, and the drive wheels 62 of the vehicle are exclusively supplied with driving force for running from the motor generator 4 for running. The internal combustion engine 1 and the drive wheels 62 are mechanically separated from each other, and originally rotational driving force is not transmitted between them. Therefore, the internal combustion engine 1 can be rotated and stopped completely independently of the motor-generator 4 and the drive wheels 62 . Therefore, during operation of the vehicle with the ignition switch (power switch or ignition key) turned on, even if the vehicle is in a state where the vehicle can run by depressing the accelerator pedal, the power storage device 3 is sufficiently charged. Under the condition that the electric charge is accumulated and the brake booster 15 has accumulated a sufficient negative pressure, the operation of the internal combustion engine 1 involving fuel combustion may not be performed.

A crankshaft, which is the rotating shaft of the internal combustion engine 1, is mechanically connected to the rotating shaft of the power generation motor generator 2 via a gear mechanism or by directly connecting the shaft. By inputting the rotational driving force output by the internal combustion engine 1 to the electric power generating motor generator 2, the electric power generating motor generator 2 generates electric power. The generated electric power is charged in the power storage device 3 and/or supplied to the traveling motor generator 4 . The power generation motor generator 2 also functions as an electric motor for motoring, which itself generates rotational driving force to rotationally drive the crankshaft of the internal combustion engine 1 . For example, the electric power generation motor generator 2 performs cranking as preparation for starting the stopped internal combustion engine 1 .

The running motor generator 4 generates driving force for running the vehicle, and inputs the driving force to the drive wheels 62 via the speed reducer 61 . In addition, the running motor generator 4 rotates together with the drive wheels 62 to generate electric power, and recovers the kinetic energy of the vehicle as electrical energy. The electric power generated by this regenerative braking charges the power storage device 3 .

Of course, if electric charge is already stored up to the capacity of the power storage device 3 and further charging is difficult, the electric power regenerated by the traveling motor generator 4 is intentionally supplied to the electric power generating motor generator 2 to generate electric power. The internal combustion engine 1 is rotationally driven by operating the internal combustion engine 2 as an electric motor. This consumes excess electric power while maintaining the braking performance of the vehicle. Further, at this time, since the rotation of the internal combustion engine 1 is maintained, fuel cut can be executed to temporarily stop the supply of fuel to the cylinders of the internal combustion engine 1 .

The power generator inverter 21 converts the AC power generated by the power generation motor generator 2 into DC power. Then, the DC power is input to power storage device 3 or drive inverter 41 . In addition, when the power generation motor generator 2 is operated as an electric motor, the power generator inverter 21 converts the DC power supplied from the power storage device 3 and/or the drive inverter 41 into AC power, and then converts the power generation motor generator 2 into AC power. to enter.

The drive inverter 41 converts the DC power supplied from the power storage device 3 and/or the generator inverter 21 into AC power and inputs the AC power to the motor generator 4 for running. In addition, the drive inverter 41 converts AC power generated by the traveling motor generator 4 when the vehicle is regeneratively braked into DC power and inputs the DC power to the power storage device 3 or the generator inverter 21 . The generator inverter 21 and the drive inverter 41 form part of a PCU (Power Control Unit) 02 .

The power storage device 3 is a battery and/or a capacitor or the like. The battery is a high-voltage secondary battery with high energy density, such as a lithium-ion secondary battery or a nickel-hydrogen secondary battery. The power storage device 3 charges and stores electric power generated by each of the motor generator 2 for power generation and the motor generator 4 for running. Power storage device 3 also discharges electric power for operating motor generator 2 for electric power generation and motor generator 4 for running as electric motors, and supplies necessary electric power to motor generators 2 and 4 .

FIG. 2 shows an outline of the internal combustion engine 1 mounted on the hybrid vehicle of this embodiment. The internal combustion engine 1 is, for example, a spark-ignited four-stroke reciprocating engine, and includes a plurality of cylinders 11 (for example, three cylinders, one of which is shown in FIG. 2). An injector 111 for injecting fuel toward the intake port is provided near the intake port of each cylinder 11 . A spark plug 112 is attached to the ceiling of the combustion chamber of each cylinder 11 . The spark plug 112 receives an induced voltage generated by the ignition coil and induces spark discharge between the center electrode and the ground electrode.

An intake passage 13 for supplying intake air takes in air from the outside and guides it to the intake port of each cylinder 11 . An air cleaner 131, an electronic throttle valve 132, a surge tank 133, and an intake manifold 134 are arranged in this order on the intake passage 13 from upstream. The air cleaner 131 is located at the most upstream intake port for taking in air in the intake passage 13 . The air intake opens to the front of the vehicle to take in cool air and increase the charging efficiency of the internal combustion engine.

An exhaust passage 14 for exhausting exhaust guides the exhaust generated as a result of burning fuel in the cylinder 11 from the exhaust port of each cylinder 11 to the outside. An exhaust manifold 142 and a three-way catalyst 141 for purifying exhaust gas are arranged on the exhaust passage 14 .

The EGR device 12 includes an external EGR passage 121 communicating between the exhaust passage 14 and the intake passage 13, an EGR cooler 122 provided on the EGR passage 121, and opening and closing the EGR passage 121 to flow the EGR gas through the EGR passage 121. and the EGR valve 123 that controls the An inlet of the EGR passage 121 is connected to a portion downstream of the catalyst 141 in the exhaust passage 14 . The outlet of the EGR passage 121 is connected to a portion of the intake passage 13 downstream of the throttle valve 132 (in particular, the surge tank 133 or the intake manifold 134).

The internal combustion engine 1 is provided with a brake booster 15 for reducing the operating force required for braking the vehicle, that is, the force applied to the brake pedal. The brake booster 15 introduces intake negative pressure from a portion (or a surge tank 133) downstream of the throttle valve 132 in the intake passage 13, and uses the negative pressure to boost the depression force of the brake pedal. It is widely known. The brake booster 15 has a constant pressure chamber (negative pressure chamber) that stores negative pressure and a variable pressure chamber (atmospheric pressure chamber) to which atmospheric pressure is applied. ing. The negative pressure line 151 guides the intake negative pressure on the downstream side of the throttle valve 132 to the constant pressure chamber. A check valve 152 is provided on the negative pressure line 151 to retain the negative pressure in the constant pressure chamber and prevent the positive pressure from being applied to the constant pressure chamber.

When the driver does not operate the brake pedal, the constant pressure chamber communicates with the variable pressure chamber, and the variable pressure chamber is isolated from the atmospheric pressure. When the brake pedal is operated, the constant pressure chamber and the variable pressure chamber are cut off, and air is introduced into the variable pressure chamber. As a result, the pressure difference between the constant pressure chamber and the variable pressure chamber becomes the control pressure that boosts the force applied to the brake pedal. The brake depression force amplified by the brake booster 15 is converted into hydraulic pressure in the master cylinder 16 . The master cylinder pressure output by the master cylinder 16 (the pressure of the brake fluid discharged by the master cylinder 16) is transmitted to a brake device such as a brake caliper or a wheel cylinder via a hydraulic circuit, and is used for braking the vehicle by the brake device. Used.

An ECU (Electronic Control Unit) 0, which is a control device for controlling the internal combustion engine 1, the motor generator 2 for power generation, the power storage device 3, the inverters 21 and 41, the motor generator 4 for running, etc., includes a processor, a memory, an input interface, and an output interface. etc. is a microcomputer system. The ECU 0 includes a plurality of ECUs, that is, an EFI (Electronic Fuel Injection) ECU 01 that controls the internal combustion engine 1, an MG (Motor Generator) ECU 02 that controls the motor generators 2 and 4 and the inverters 21 and 41, and a BMS that controls the power storage device 3. (Battery Management System) ECU 03, etc., and HV (Hybrid Vehicle) ECU 00, which is a higher-level controller for controlling them, are connected so as to be able to communicate with each other via an electric communication line such as CAN (Controller Area Network). It is a thing.

For the ECU 0, a vehicle speed signal a output from a vehicle speed sensor that detects the actual vehicle speed, a crank angle signal b output from a crank angle sensor that detects the rotation angle of the crankshaft of the internal combustion engine 1 and the engine speed , an accelerator opening signal output from a sensor that detects the amount of depression of the accelerator pedal by the driver as an accelerator opening (in other words, the driving force that the driver requests for the vehicle (the motor generator 4 for traveling)). c, an intake air temperature/intake pressure signal d output from a temperature/pressure sensor that detects the intake air temperature and pressure in the intake passage 13 (in particular, the surge tank 133 or the intake manifold 134) connected to the cylinders 11 of the internal combustion engine 1; A cooling water temperature signal e output from a water temperature sensor for detecting the temperature of the cooling water of the internal combustion engine 1, and an output from a vibrating knock sensor for detecting the magnitude of vibration of the cylinder block containing the cylinders 11 of the internal combustion engine 1. A vibration signal f to be applied, a battery SOC (State Of Charge) signal g output from a sensor (in particular, a battery current and/or battery voltage sensor) that detects the amount of charge stored in the power storage device 3, and a constant pressure of the brake booster 15 A negative pressure signal h or the like output from a negative pressure sensor that detects the negative pressure stored in the chamber is input.

The ECU 0 senses the amount of depression of the accelerator pedal operated by the driver, the current vehicle speed, the amount of charge stored in the power storage device 3, and the power generation motor generator 2, which is sensed via various sensors. The rotational driving force output by the motor generator 4 for running, the rotational driving force output by the internal combustion engine 1, and the magnitude of the electric power generated by the motor generator 2 are controlled to increase or decrease according to the generated electric power.

In principle, if the output required for the motor generator 4 for running the vehicle is small, the supply of fuel to the internal combustion engine 1 is cut off and the internal combustion engine 1 is not operated. On the other hand, if the required output of the motor-generator 4 for traveling is large, the internal combustion engine 1 is started, fuel is supplied to the cylinder 11, and firing is performed to burn the fuel, and the internal combustion engine 1 outputs. The rotational driving force drives the generator motor generator 2 to generate power to increase the electric power supplied to the traveling motor generator 4 or to charge the power storage device 3 .

The output required for the motor generator 4 for running the vehicle is determined by the amount of depression of the accelerator pedal operated by the driver and the vehicle speed. The driving force to be applied to the drive wheels 62 increases as the accelerator opening increases. Then, the required output of the traveling motor generator 4 increases as the driving force to be applied to the driving wheels 62 increases, and increases as the vehicle speed increases.

Ultimately, when the driver of the vehicle strongly depresses the accelerator pedal to start or accelerate the vehicle, the required output of the motor-generator 4 for running is increased, so the internal combustion engine 1, which had been stopped until then, is started. Become. It should be noted that even when the amount of charge (SOC) stored in the power storage device 3 decreases below the lower limit value, or when the negative pressure stored in the constant pressure chamber of the brake booster 15 decreases below the lower limit value, the internal combustion engine 1 may be started.

The internal combustion engine 1 is started while the fuel is not being supplied to the cylinders 11 of the internal combustion engine 1 and the internal combustion engine 1 is not being operated, and the drive wheels 62 are being driven by the traveling motor generator 4 to drive the vehicle. In order to execute power generation by the motor generator 2 for power generation, first, the motor generator 2 for power generation is operated as an electric motor, thereby performing motoring for starting the internal combustion engine 1 . Then, when the crankshaft of the internal combustion engine 1 rotates a predetermined number of times or more or at a predetermined angle or more, and cylinder discrimination for obtaining the current stroke or piston position of each cylinder 11 of the internal combustion engine 1 is completed, each cylinder of the internal combustion engine 1 Fuel is injected at appropriate timing in accordance with the stroke of the cylinder 11, and firing for igniting and burning the fuel is started at appropriate timing. The rotation angle and rotation speed of the crankshaft of the internal combustion engine 1, i.e., the engine speed, can be detected (in the MG ECU 02) via a resolver attached to the motor generator 2 for power generation. can also be detected (at the EFI ECU01).

If the internal combustion engine 1 can rotate independently and output the rotational driving force necessary for power generation, and the engine speed can maintain an upward trend even when the output of the motor generator 2 for power generation is reduced. For example, the output of the power generation motor generator 2 operating as an electric motor is reduced to 0 to end the motoring, and the power generation motor generator 2 is rotationally driven by the internal combustion engine 1 this time. Furthermore, the power generation motor generator 2 is operated as a power generator, and the generated power is increased from zero.

Thereafter, the intake air amount and the fuel injection amount supplied to the cylinder 1 of the internal combustion engine 1 and the electric power generated by the power generation motor generator 2 are increased or decreased so that the engine speed follows the target speed, which is increased in stages. .

An EFI ECU 01 forming a part of the ECU 0 acquires various types of information b, d, e, and f necessary for controlling the operation of the internal combustion engine 1 through an input interface, learns the engine speed, and injects the information into the cylinder 11. Estimate the amount of air. Then, the required fuel injection amount (necessary for realizing the target air-fuel ratio) matching the intake air amount, fuel injection timing (including the number of fuel injections for one combustion), fuel injection pressure, ignition timing (one time It determines operating parameters of the internal combustion engine 1 such as the number of ignitions for combustion), the required EGR rate (or EGR gas amount), and the like. The EFI ECU 01 outputs various control signals i, j, k, l corresponding to operating parameters to the igniter of the ignition plug 112, the injector 111, the throttle valve 132, the EGR valve 123, etc. via the output interface.

The ECU 0 of this embodiment adjusts the engine output of the internal combustion engine 1 during firing operation according to the output required of the motor generator 4 for traveling, and adjusts the power generated by the motor generator 2 for power generation driven by the internal combustion engine 1 during firing operation. Increase or decrease. The contents of the control by the ECU 0 of the present embodiment will be described in detail below with examples of numerical values, but this is merely for the sake of convenience in simplifying the explanation, and the numerical values are not actually adopted. Not exclusively.

As a premise, the thermal efficiency of the internal combustion engine 1 (or the efficiency of the entire system considering the characteristics of the PCU 02) is good in the output range of 14 kW to 24 kW, and the efficiency is low in the lower or higher output range. shall worsen. The output with the minimum fuel consumption rate is assumed to be 18 kW. The output (generated electric power) of the motor-generator 2 for power generation as a generator and the output of the motor-generator 4 as an electric motor can both be increased to a little over 40 kW.

As shown in FIG. 3, the ECU 0 changes the content of control according to which of the following regions I, II, and III the current required output corresponds.
<Low Output Region I: Required Output for Motor Generator 4 for Traveling is Smaller than 14 kW>
In this region I, if the internal combustion engine 1 does not have to fire, it does not fire. If it has to fire, the output of the internal combustion engine 1 is increased above the value W _L at which the efficiency is good.

In region I, the ECU 0 compares the required output of the traction motor generator 4 with a threshold set according to the current SOC level, and determines whether or not the internal combustion engine 1 needs to be fired. If the required output is greater than or equal to the threshold, the internal combustion engine 1 is started and fired. If the required power is below the threshold, the internal combustion engine 1 is not started and not fired.

Supplementally, the SOC level is an index value indicating the amount of charge currently stored in the power storage device 3. The higher the value, the larger the amount of stored electricity, and the lower the value, the smaller the amount of stored electricity. Specifically, if the current SOC of the power storage device 3 is 75% or more, the SOC level is 5; if 65% or more and less than 75%, level 4; If it is less than 35%, it is defined as level 0. However, the SOC level may be corrected according to factors other than the charged amount, such as vehicle speed. When the current SOC of the power storage device 3 is 65%, it basically corresponds to SOC level 4, but if the current vehicle speed is higher than 60 km/h, the SOC level is corrected from 4 to 5. can do The reason why the SOC level is raised when the vehicle speed is high compared to when the vehicle speed is low is that if the current vehicle speed is high, there will be an opportunity to recover electric power to the power storage device 3 by later regenerative braking.

In addition, the higher the SOC level, the higher the threshold to be compared with the required output. For example, under SOC level 5, the threshold is 10 kW, under SOC level 4, the threshold is 8 kW, ..., under SOC level 1, the threshold is 2 kW, and under SOC level 0, the threshold is 2 kW. 0 kW (in short, the internal combustion engine 1 is always started and fired).

When the required output for the running motor generator 4 is below the above threshold, the internal combustion engine 1 is not fired, and the power storage device 3 exclusively supplies the required electric power to the running motor generator 4 . Under the condition of SOC level 5, if the required output is 8 kW, this is below the threshold value of 10 kW. to drive the vehicle. This avoids unnecessary consumption of fuel. In addition, there is also the implication that electric charge is discharged from the power storage device 3, which is in a nearly fully charged state, to create an empty capacity to prepare for later regenerative braking.

Alternatively, if the required output is 12 kW under the condition of SOC level 1, this exceeds the threshold value of 2 kW. Suppose that it is supplied to the motor generator 4 .

In region I, when the internal combustion engine 1 fires, the output of the internal combustion engine 1 is always set to the value W at which the efficiency is good even if the required output of the motor generator 4 for traveling is smaller than the value W _L . Adjust the magnitude between _L and the value W _H . That is, the output of the internal combustion engine 1 is determined regardless of the required output. This is to prevent the thermal efficiency of the internal combustion engine 1 from deteriorating due to the low output operation.

The output of the internal combustion engine 1 during firing is decreased as the current SOC level is higher, and is increased as the current SOC level is lower. For example, as shown in FIG. 4, assuming that the required output is a value _W11 smaller than the value _WL , under the condition of SOC level 5, the output of the internal combustion engine 1 is adjusted to the same magnitude as _WL . . Ignoring the characteristics of the power generation motor generator 2 and the PCU 02 as well as the charging efficiency of the power storage device 3, the power generation motor generator 2 generates and outputs electric power of the value W _L , and the required output W ₁₁ thereof is used for driving. The power is supplied to the motor generator 4, and the surplus (W _L -W ₁₁ ) is used to charge the power storage device 3 or to supply the electric load of the electrical system of the vehicle.

Under SOC level 4 conditions, the output of the internal combustion engine 1 is adjusted to a value W ₁₂ greater than under SOC level 5 conditions (closer to the minimum specific fuel consumption). As a result, the motor generator 2 for power generation generates and outputs the electric power of W ₁₂ , of which the requested output W ₁₁ is supplied to the motor generator 4 for traveling, and the surplus (W ₁₂ −W ₁₁ ) is supplied to the power storage device 3. It charges and supplies the electrical loads of the vehicle's electrical system.

Under conditions of SOC level 1, the output of the internal combustion engine 1 is adjusted to a value _W13 greater than under conditions of SOC level 2 (away from the minimum specific fuel consumption). As a result, the electric power generation motor generator 2 generates and outputs electric power W ₁₃ , of which the required output W ₁₁ is supplied to the traveling motor generator 4 and the surplus (W ₁₃ −W ₁₁ ) is supplied to the power storage device 3. It charges and supplies the electrical loads of the vehicle's electrical system.

In any case, in the area I, the electric charge is not discharged from the power storage device 3 and supplied to the traveling motor generator 4 . Thereby, the occurrence of loss due to the discharge efficiency of the power storage device 3 can be avoided.
<Preferred Output Region II: Required Output for Traveling Motor Generator 4 is 14 kW or More and Less than 24 kW>
In this region II, the internal combustion engine 1 is fired because the efficiency is good.

In region II, when the internal combustion engine 1 fires, its output is adjusted to a magnitude between values _WL and _WH that result in good efficiency. The output of the internal combustion engine 1 is determined independently of the required output. The output of the internal combustion engine 1 during firing is decreased as the current SOC level is higher, and is increased as the current SOC level is lower. For example, as shown in FIG. 5, assuming that the required output is _WL , under the condition of SOC level 5, the output of the internal combustion engine 1 is adjusted to _W21 . Ignoring the characteristics of the motor generator 2 for power generation and the PCU 02 and the charging efficiency of the power storage device 3, the motor generator 2 for power generation generates and outputs electric power of _W21 , and the required output W _L is used by the driving motor. The power is supplied to the generator 4, and the surplus (W ₂₁ -W _L ) is used to charge the power storage device 3 or to supply the electrical load of the electrical system of the vehicle.

Under SOC level 4 conditions, the output of the internal combustion engine 1 is adjusted to _W22 , which is greater than under SOC level 5 conditions. As a result, the electric power generation motor generator 2 generates and outputs electric power of W ₂₂ , of which the requested output W _L is supplied to the traveling motor generator 4 and the surplus (W _L - W ₂₂ ) is supplied to the power storage device 3. It charges and supplies the electrical loads of the vehicle's electrical system.

Under the SOC level 1 situation, the output of the internal combustion engine 1 is adjusted to W _H larger than under the SOC level 2 situation. As a result, the electric power generation motor generator 2 generates and outputs electric power W _H , of which the required output W _L is supplied to the traveling motor generator 4 and the surplus (W _H −W _L ) is supplied to the power storage device 3 . It charges and supplies the electrical loads of the vehicle's electrical system.

In region I, the output of internal combustion engine 1 always exceeds the required output of motor generator 4 for running, but in region II, the output of internal combustion engine 1 falls below the required output of motor generator 4 for running due to the SOC level. There is For example, as shown in FIG. 6, assuming that the required output is _W23 , under the condition of SOC level 5, the output of the internal combustion engine 1 is also adjusted to _W21 . The electric power generation motor generator 2 generates electric power of W ₂₁ and outputs it, and supplies the electric power to the traveling motor generator 4 . Although the generated electric power for the required output W ₂₃ is short by (W ₂₃ −W ₂₁ ), the shortfall is supplied from the power storage device 3 to the traveling motor generator 4 .

Under the condition of SOC level 4, the output of the internal combustion engine 1 is adjusted to _W24 . As a result, the motor-generator 2 for power generation generates and outputs the electric power of W ₂₄ and supplies the electric power to the motor-generator 4 for running. Although the generated electric power for the required output W ₂₃ is short by (W ₂₃ −W ₂₄ ), the shortfall is supplied from the power storage device 3 to the traveling motor generator 4 .

Under the condition of SOC level 1, the output of the internal combustion engine 1 is adjusted to W _H . As a result, the electric power generation motor generator 2 generates and outputs electric power W _H , of which the required output W ₂₃ is supplied to the traveling motor generator 4 and the surplus (W _H −W ₂₃ ) is supplied to the power storage device 3. It charges and supplies the electrical loads of the vehicle's electrical system.

In region II, when the SOC level is high and the power storage device 3 is nearly fully charged, electric charge is discharged from the power storage device 3 and supplied to the traveling motor generator 4 . When the SOC level is low and the electric charge stored in the power storage device 3 is insufficient, the electric power generated by the electric power generation motor generator 2 is increased within a good efficiency range to charge the power storage device 3 . When the SOC level is intermediate, that is, when the power storage device 3 stores an appropriate amount of electric charge, all of the electric power generated by the power generation motor generator 2 is supplied to the traveling motor generator 4 as it is to cover the required output, and the power storage device 3 Do not charge or discharge the As a result, it is possible to avoid the loss due to the charging efficiency and discharging efficiency of the power storage device 3 .
<High Output Region III: The Required Output for the Traveling Motor Generator 4 is 24 kW or More>
Firing of the internal combustion engine 1 is unavoidable in this region III where the required output is large. Moreover, the output of the internal combustion engine 1 must be increased even if the deterioration in efficiency is accepted.

In regions I and II, the output of the internal combustion engine 1 is determined according to the SOC level regardless of the required output of the motor generator 4 for running. However, in region III, the output of the internal combustion engine 1 is determined by referring to both the required output and the SOC level. In region III,
[output of internal combustion engine 1]+[power balance of power storage device 3]=[required output of motor generator 4 for traveling]
and

In principle, the output of the internal combustion engine 1 during firing increases as the required output of the traction motor generator 4 increases. The second term on the left side of the above equation, "power balance of power storage device 3", may take a positive value or a negative value. If the power balance of the power storage device 3 is a positive value, it means that the electric power output from the motor generator 2 for power generation driven by the internal combustion engine 1 does not meet the required output for the motor generator 4 for traveling, and the shortage of electric power is supplied. It means that power is supplied from the power storage device 3 to the traveling motor generator 4 . The fact that the power balance of the power storage device 3 is a negative value means that the power generated and output by the motor-generator 2 for power generation exceeds the required output for the motor-generator 4 for traveling, and the power storage device 3 is charged with the surplus power. means.

In region III, the ECU 0 sets the power balance of the power storage device 3 in the above equation to a larger value as the current SOC level is higher, and a smaller value as the SOC level is lower. For example, 7 kW under SOC level 5, 4 kW under SOC level 4, . . . −10 kW under SOC level 1, and −20 kW under SOC level 0. If the required output of the traveling motor generator 4 is the same, the lower the SOC level, the more the output of the internal combustion engine 1 must be increased.

As shown in FIG. 7, assuming that the required output is _W31 , under the condition of SOC level 5, the output of the internal combustion engine 1 is adjusted to _W32 . Ignoring the characteristics of the power generation motor generator 2 and the PCU 02 as well as the charging efficiency of the power storage device 3, the power generation motor generator 2 generates and outputs electric power of W ₃₂ and supplies the electric power to the traveling motor generator 4. . The generated power for the required output is short by (W ₃₁ -W ₃₂ ), and the shortfall is supplied from the power storage device 3 to the traveling motor generator 4 .

Under the condition of SOC level 4, the output of the internal combustion engine 1 is adjusted to _W33 . As a result, the motor-generator 2 for power generation generates and outputs the electric power of W ₃₃ and supplies the electric power to the motor-generator 4 for running. The generated power for the required output is short by (W ₃₁ -W ₃₃ ), and the shortfall is supplied from the power storage device 3 to the traveling motor generator 4 .

Under the condition of SOC level 1, the output of the internal combustion engine 1 is adjusted to _W34 . As a result, the electric power generation motor generator 2 generates and outputs electric power W ₃₄ , of which the required output W ₃₁ is supplied to the traveling motor generator 4 and the surplus (W ₃₄ −W ₃₁ ) is supplied to the power storage device 3. It charges and supplies the electrical loads of the vehicle's electrical system.

In this embodiment, the electric power generated by driving the generator 2 by the internal combustion engine 1 is charged in the power storage device 3 or supplied to the electric motor 4, and the electric motor 4 drives the driving wheels 62 to drive the hybrid vehicle. The output required of the electric motor 4 for running the vehicle is within a predetermined range (14 kW to 24 kW, region II) where the thermal efficiency of the internal combustion engine 1 is considered to be good, or below (less than 14 kW, When the size is in the region I), the output of the internal combustion engine 1 is controlled within the predetermined range to generate power by the generator 2, and the ratio between the power supplied from the generator 2 to the electric motor 4 and the required output is determined. A control device 0 for a hybrid vehicle is configured in which the power storage device 3 is charged with the difference (surplus or deficit) or power is supplied from the power storage device 3 .

In particular, in controlling the output of the internal combustion engine 1 within the predetermined range, the control device 0 of the present embodiment increases the output of the internal combustion engine 1 as the current storage amount of the power storage device 3 decreases.

In this embodiment, the output of the internal combustion engine 1 that is in firing operation is kept within a range that maximizes efficiency. In addition, the power generated by the generator 2 is supplied directly to the electric motor 4 as much as possible (excluding the power generated and recovered by regenerative braking), avoiding the charging and discharging of the power storage device 3, and improving the charging efficiency and Reduce energy loss due to discharge efficiency. According to this embodiment, it is possible to further improve the practical fuel consumption performance of the hybrid vehicle.

The present invention is not limited to the embodiments detailed above. For example, the application of the present invention is not limited to a series hybrid vehicle.

In addition, the specific configuration of each part, the procedure of processing, and the like can be variously modified without departing from the spirit of the present invention.

0... Control unit (ECU)
1... Internal combustion engine 2... Generator (motor generator for power generation)
3 power storage device 4 electric motor (motor generator for traveling)
62... Drive wheel

Claims (2)

The electric power generated by driving the generator by the internal combustion engine is charged to the power storage device or supplied to the electric motor, and the electric motor drives the drive wheels to control the hybrid vehicle that runs.
When the output required of the electric motor for running the vehicle is within or below a predetermined range in which the thermal efficiency of the internal combustion engine is considered to be good, the output of the internal combustion engine is reduced to a magnitude within that predetermined range. A control device for a hybrid vehicle that controls a power generator to generate power, and charges a power storage device with the difference between the power supplied to the motor from the power generator and the required output, or supplies power from the power storage device. 2. A control system for a hybrid vehicle according to claim 1, wherein, in controlling the output of the internal combustion engine to be within the predetermined range, the output of the internal combustion engine is increased as the amount of current stored in the power storage device decreases.

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