JP7299122B2 - HYBRID VEHICLE CONTROL METHOD AND HYBRID VEHICLE CONTROL DEVICE - Google Patents

Description

The present invention relates to a control method and apparatus for a hybrid vehicle having a variable compression ratio internal combustion engine capable of changing the compression ratio.

2. Description of the Related Art An internal combustion engine is widely known that has a variable compression ratio mechanism that utilizes a multi-link type piston crank mechanism and that can change the compression ratio by driving the variable compression ratio mechanism with an actuator.

For example, in Patent Document 1, when there is an acceleration request, the target compression ratio of the internal combustion engine is corrected to a lower compression ratio side than the reference target compression ratio according to the engine operating conditions during steady state. A technique is disclosed for avoiding adverse effects on the durability of the variable compression ratio mechanism by limiting the intake pressure so that the maximum combustion pressure does not exceed the allowable combustion pressure.

WO2019/003326

However, in Patent Document 1, no consideration is given to the actuation energy required for the actuator when driving the variable compression ratio mechanism to change the compression ratio. The larger the actuation energy required to drive the variable compression ratio mechanism, the larger the actuator and the higher the cost.

In other words, in an internal combustion engine having a variable compression ratio mechanism, there is room for further improvement in reducing the size and cost of the actuator that drives the variable compression ratio mechanism.

In the hybrid vehicle of the present invention, the compression ratio of the internal combustion engine is changed from a predetermined first compression ratio to the first compression ratio during power generation by driving the generator motor with the internal combustion engine, the compression ratio of which can be changed by operating the actuator. When switching to a predetermined second compression ratio higher than the compression ratio, the amount of reduction in the load of the internal combustion engine is changed according to the power generation request. At this time, if the demand for power generation is large, the compression ratio of the internal combustion engine is changed to the second compression ratio while generating power, and if the demand for power generation is small, the battery is charged or the drive motor is driven. The compression ratio of the internal combustion engine is changed to the second compression ratio after the power generation by the generator motor is stopped. Here, when the demand for power generation is small, the SOC of the battery is equal to or higher than a predetermined SOC, and when the demand for power generation is large, the SOC of the battery is less than the predetermined SOC.

The hybrid vehicle of the present invention can reduce the energy required to operate the actuator when changing the compression ratio of the internal combustion engine to a higher value.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram schematically showing an outline of a hybrid vehicle drive system to which the present invention is applied; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram schematically showing the schematic configuration of a variable compression ratio mechanism of an internal combustion engine mounted on a hybrid vehicle to which the present invention is applied; FIG. 4 is a characteristic diagram showing a first operating range A1 and a second operating range A2 set in advance. 4 is a flow chart showing the control flow of a hybrid vehicle to which the present invention is applied; 4 is a flow chart showing the flow of control when switching the target power generation mode in a hybrid vehicle to which the present invention is applied;

An embodiment of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram schematically showing an outline of a hybrid vehicle drive system to which the present invention is applied.

The hybrid vehicle shown in FIG. 1 has a generator motor 1 that mainly operates as a generator, and a generator internal combustion engine that drives the generator motor 1 in accordance with a power generation request (electric power request). The compression ratio can be changed. an internal combustion engine (variable compression ratio internal combustion engine) 2, a battery 3 that temporarily stores the generated electric power, a drive motor 4 that rotates the drive wheels of the hybrid vehicle, and a VCM (vehicle control system) that controls the running of the hybrid vehicle. 5, an ECM (engine control module) 6 that controls the internal combustion engine 2, and a VCR controller 7 that controls the compression ratio of the internal combustion engine 2. VCM 5, ECM 6 and VCR controller 7 are known digital computers with CPU, ROM, RAM and input/output interfaces.

The hybrid vehicle of this embodiment is a so-called series hybrid vehicle that does not use the internal combustion engine 2 as power. That is, in the hybrid vehicle of this embodiment, the internal combustion engine 2 is dedicated to power generation, and the drive motor 4 drives the drive wheels to run. In the hybrid vehicle of this embodiment, for example, when the SOC of the battery 3 decreases (the remaining amount of the battery 3 decreases), the internal combustion engine 2 is driven to charge the battery 3 and the generator motor 1 generates power. .

The generator motor 1 is, for example, a synchronous motor using a permanent magnet for its rotor. The generator motor 1 converts rotational energy generated in the internal combustion engine 2 into electrical energy to charge a battery 3, for example. The generator motor 1 also functions as an electric motor for driving the internal combustion engine 2, and functions as a starter motor when the internal combustion engine 2 is started. That is, the generator motor 1 can supply the generated electric power to the battery 3 and can be rotationally driven by the electric power from the battery 3 .

The power generated by the generator motor 1 may be directly supplied to the drive motor 4 instead of being charged to the battery 3, for example, depending on the operating state. Further, the internal combustion engine 2 may be started by a dedicated starter motor different from the generator motor 1, for example.

The battery 3 can be charged with electric power obtained by the internal combustion engine 2 driving the generator motor 1 or electric power obtained from the drive motor 4 .

The drive motor 4 is a direct drive source for the hybrid vehicle, and is driven by AC power from the battery 3, for example. The drive motor 4 is, for example, a synchronous motor using a permanent magnet for its rotor.

Further, the drive motor 4 functions as a generator during deceleration of the hybrid vehicle. In other words, the drive motor 4 can charge the battery 3 by using regenerated energy when the vehicle decelerates as electric power.

The VCM 5 controls the drive motor 4 according to the operating state of the hybrid vehicle. The VCM 5 sets a control command value (drive motor operation command value), target power generation amount, etc. The SOC of the battery 3 is calculated based on the terminal voltage of the battery 3, for example. The amount of operation of the accelerator pedal is detected by an accelerator opening sensor (not shown). In addition, the VCM 5 is connected to the ECM 6 via the first in-vehicle network 8 and exchanges signals with each other. The ECM 6 is connected to the VCR controller 7 via the second in-vehicle network 9 and exchanges signals with each other.

The ECM 6 controls the internal combustion engine 2 according to the power generation request of the hybrid vehicle. The ECM 6 outputs a control command value ( The internal combustion engine operation command value) and the target compression ratio of the internal combustion engine 2 are calculated. The engine speed of the internal combustion engine 2 can be detected by a crank angle sensor (not shown) that detects the crank angle of a crankshaft 16 (described later) of the internal combustion engine 2 . The actual compression ratio of the internal combustion engine 2 is input from the VCR controller 7 via the second in-vehicle network 9, for example.

The VCR controller 7 calculates the actual compression ratio of the internal combustion engine 2 from the rotation angle of a first control shaft 21 (described later) of the internal combustion engine 2 . A rotation angle of a first control shaft 21 (described later) of the internal combustion engine 2 is detected by a first control shaft rotation angle sensor (not shown).

Also, the VCR controller 7 calculates a target rotation angle of the first control shaft 21 (described later) according to the target compression ratio of the internal combustion engine 2 . The VCR controller 7 controls the compression ratio of the internal combustion engine 2 by controlling the rotation angle of a first control shaft 21 (described later) of the internal combustion engine so that it reaches a target rotation angle. That is, the VCR controller 7 controls the compression ratio of the internal combustion engine 2 according to the target compression ratio calculated by the ECM6. In other words, the VCR controller 7 controls the operation of the internal combustion engine 2 according to the power generation request.

FIG. 2 is an explanatory diagram schematically showing the schematic configuration of a variable compression ratio mechanism 11 capable of changing the compression ratio of the internal combustion engine 2 mounted on a hybrid vehicle to which the present invention is applied.

The variable compression ratio mechanism 11 is roughly composed of a piston 12, an upper link 13 as a first link, a lower link 14 as a second link, and a control link 15 as a third link. The variable compression ratio mechanism 11 is a multi-link piston crank mechanism in which the piston 12 and the crankpin 16a of the crankshaft 16 are linked by a plurality of links.

Piston 12 is rotatably connected to one end of upper link 13 via piston pin 17 .

The other end of the upper link 13 is rotatably connected to one end side of the lower link 14 via an upper pin 18 as a first link connecting pin.

The crankshaft 16 has a plurality of journal portions 16b and crankpins 16a. The crankpin 16a is eccentric by a predetermined amount from the journal portion 16b.

The lower link 14 is rotatably connected to the crankpin 16a of the crankshaft 16. As shown in FIG.

One end of the control link 15 is rotatably connected to the other end side of the lower link 14 via a control pin 20 as a third link connecting pin.

The other end of the control link 15 is rotatably connected to the eccentric shaft portion 21a of the first control shaft 21 supported on the engine body side.

A metal first control shaft 21 is arranged parallel to the crankshaft 16 and rotatably supported by, for example, the cylinder block 19 . In other words, the other end of the control link 15 rotatably connected to the metal eccentric shaft portion 21a is swingably supported on the engine body side. The central axis of the eccentric shaft portion 21a is eccentrically positioned relative to the center of rotation of the first control shaft 21 by a predetermined amount.

By rotating the first control shaft 21 to change the position of the eccentric shaft portion 21a, the variable compression ratio mechanism 11 can change the position of the piston 12 at the top dead center, thereby changing the mechanical compression ratio of the internal combustion engine. can do.

The first control shaft 21 regulates the degree of freedom of the lower link 14 and its rotational position is changed and held by the actuator 22 .

The first control shaft 21 has a metal first arm portion 23 . The first arm portion 23 extends radially outward of the first control shaft 21 . That is, the first arm portion 23 protrudes from the first control shaft 21 .

The actuator 22 consists of an electric motor, for example. The rotation of the actuator 22 is decelerated by a speed reducer (not shown) and picked up as the rotation of the second control shaft 24 made of metal. That is, the second control shaft 24 is connected to the actuator 22 via the speed reducer.

The second control shaft 24 is arranged parallel to the first control shaft 21 and extends in the longitudinal direction of the engine.

The second control shaft 24 has a metal second arm portion 25 . The second arm portion 25 extends radially outward of the second control shaft 24 . That is, the second arm portion 25 protrudes from the second control shaft 24 .

The first arm portion 23 and the second arm portion 25 are mechanically connected by an elongated metal lever 26 orthogonal to the first control shaft 21 and the second control shaft 24 .

The first arm portion 23 and the lever 26 are rotatably connected via a metal first connecting pin 27 . The first connecting pin 27 passes through the tip of the first arm portion 23 and one end of the lever 26 in parallel with the first control shaft 21 .

The second arm portion 25 and the lever 26 are rotatably connected via a metal second connecting pin 28 . The second connecting pin 28 passes through the tip of the second arm portion 25 and the other end of the lever 26 in parallel with the second control shaft 24 .

When the second control shaft 24 rotates as the actuator 22 rotates, the second arm portion 25 swings as the second control shaft 24 rotates, causing the lever 26 to reciprocate along a plane perpendicular to the first control shaft 21 . do. As the lever 26 reciprocates, the first arm portion 23 swings, thereby rotating the first control shaft 21 .

That is, the actuator 22 can change and hold the rotational position of the first control shaft 21 by changing and holding the rotational position of the second control shaft 24 .

FIG. 3 shows a first operating region A1 and a second operating region A2 preset with the engine speed and load of the internal combustion engine 2 as parameters. WOT indicated by a solid line in FIG. 3 indicates the fully open characteristic of the internal combustion engine 2 .

The first operating region A1 is set on the high rotation and high load side relative to the second operating region A2. The second operating region A2 is set to be on the relatively low load side and include the best fuel consumption point of the internal combustion engine 2 . The first operating area A1 and the second operating area A2 are discontinuous.

The compression ratio in the first operating region A1 is set lower than the compression ratio in the second operating region A2. A first compression ratio, which is the compression ratio of the internal combustion engine 2 in the first operating region A1, is set to, for example, "10". A second compression ratio, which is the compression ratio of the internal combustion engine 2 in the second operating region A2, is set to, for example, "15".

The internal combustion engine 2 is operated at a predetermined operating point (operating point). The operating point of the internal combustion engine 2 is mainly determined by the operating state, and is defined by the combination of the load and the engine speed.

The internal combustion engine 2 is operated at a first operating point P1 within a first operating region A1 when power generation is performed at maximum output, and is within a second operating region A2 when power generation is performed at high efficiency with emphasis on fuel consumption. It is operated at a certain second operating point P2. The first operating point P1 is set to the maximum power point of the internal combustion engine 2, for example. The second operating point P2 is set to the best fuel efficiency point of the internal combustion engine 2, for example.

The operating point for idling the internal combustion engine 2 is the third operating point P3, which is lower in speed and load than in the second operating region A2. The fourth operating point P4 in FIG. 3 is the operating point when the internal combustion engine 2 is stopped.

The internal combustion engine 2, which changes the compression ratio by changing the top dead center position of the piston 12, resists the combustion load acting in the direction of pushing down the piston 12 when changing the compression ratio from a low compression ratio to a high compression ratio. Therefore, the energy required to operate the actuator 22 is greater than when changing the compression ratio from a high compression ratio to a low compression ratio.

Therefore, in the hybrid vehicle, the compression ratio of the internal combustion engine 2 is changed from a low compression ratio (first compression ratio) to a high compression ratio (second compression ratio) when the internal combustion engine 2 is driven and the generator motor 1 is generating power. , the amount of reduction in the load of the internal combustion engine 2 is changed according to the power generation request.

That is, when the hybrid vehicle changes the compression ratio of the internal combustion engine 2 from a low compression ratio (first compression ratio) to a high compression ratio (second compression ratio) while the generator motor 1 is generating power, the ECM 6 as a control unit and the VCR controller 7 reduces the load of the internal combustion engine 2 according to the power generation request, and then changes the compression ratio of the internal combustion engine 2 from a low compression ratio (first compression ratio) to a high compression ratio (second compression ratio). do.

More specifically, the hybrid vehicle drives the internal combustion engine 2 and changes the operating point of the internal combustion engine 2 from the first operating point P1 in the first operating region A1 to the When switching to the second operating point P2, if the power generation request is small, the operating point of the internal combustion engine 2 is changed from the first operating point P1 to the third operating point P3 to charge the battery 3 or drive the driving motor 4. After power generation by the generator motor 1 is stopped (power generation for maintaining the internal combustion engine 2 in an idle state is continued), the compression ratio of the internal combustion engine 2 is switched from the first compression ratio to the second compression ratio. After switching the compression ratio from the first compression ratio to the second compression ratio, the operating point of the internal combustion engine 2 is changed from the third operating point P3 to the second operating point P2.

In addition, the hybrid vehicle drives the internal combustion engine 2 to generate power by the generator motor 1, and the operating point of the internal combustion engine 2 is changed from the first operating point P1 in the first operating region A1 to the second operation in the second operating region A2. When switching to the point P2, if the power generation request is large, the operating point of the internal combustion engine 2 is changed from the first operating point P1 to the second operating point P2, and the compression ratio of the internal combustion engine 2 is increased while continuing the power generation by the generator motor 1. Switch from the first compression ratio to the second compression ratio.

The magnitude of the power generation request is, for example, the SOC of the battery 3, the power consumption E of the hybrid vehicle, the power generation amount O (target power generation amount) required for the internal combustion engine 2 (generator motor 1), the internal combustion engine 2 (generator motor 1), It is determined by, for example, how long the vehicle can run even if power generation is stopped according to 1).

Specifically, when the power generation request is small, the SOC of the battery 3 is equal to or higher than a predetermined SOCt, and when the power generation request is high, the SOC of the battery 3 is less than the predetermined SOCt.

Further, when the power generation request is small, the power consumption E of the hybrid vehicle is equal to or less than the predetermined power consumption Et, and when the power generation request is large, the power consumption E of the hybrid vehicle is less than the predetermined power consumption Et is greater than

The case where the power generation request is small means that the power generation amount O required of the internal combustion engine 2 (generator motor 1) is equal to or less than the predetermined power generation amount Ot, and the case that the power generation request is large means that the internal combustion engine 2 (generator motor 1) 1) is the case where the requested power generation amount O is greater than the predetermined power generation amount Ot. The power generation amount O required of the internal combustion engine 2 is determined by, for example, the SOC of the battery 3, the load of the internal combustion engine 2, the temperature of the cooling water of the internal combustion engine 2, and the like.

Alternatively, when the demand for power generation is small, it means that the permissible power generation stop time T, which is the time during which the vehicle can run even if power generation by the internal combustion engine 2 is stopped by driving the generator motor 1, is greater than or equal to the predetermined permissible power generation stop time Tt. When the demand for power generation is large, the permissible power generation stop time T, which is the time during which the vehicle can run even if power generation by the internal combustion engine 2 is stopped by driving the generator motor 1, is longer than the predetermined permissible power generation stop time Tt. This is the case when it is small. When the allowable power generation stop time T is equal to or longer than the predetermined allowable power generation stop time Tt, the load input (input torque) from the internal combustion engine 2 to the actuator 22 can be suppressed by switching the compression ratio after power generation is stopped.

In short, if even one of the following (1) to (4) applies, it is determined that the power generation request is small, and if none of the following (1) to (4) apply, power generation Request is determined to be large.
(1) The SOC of the battery 3 is equal to or higher than a predetermined SOCt.
(2) The electric power consumption E of the hybrid vehicle is equal to or less than the predetermined electric power consumption Et.
(3) The power generation amount O required of the internal combustion engine 2 (generator motor 1) is equal to or less than the predetermined power generation amount Ot.
(4) The allowable power generation stop time T is equal to or longer than the predetermined allowable power generation stop time Tt.
Note that the predetermined SOCt, the predetermined power consumption Et, the predetermined power generation amount Ot, and the predetermined power generation stoppage allowable time Tt described above are, for example, values set by adaptation experiments using actual machines.

As a result, the hybrid vehicle can reduce the energy required to operate the actuator 22 when changing the compression ratio of the internal combustion engine 2 to a higher value.

Further, in the hybrid vehicle, the maximum output required for the actuator 22 of the internal combustion engine 2 can be reduced, and the size of the actuator 22 can be reduced.

When the internal combustion engine 2 changes the compression ratio while receiving inertial force, an alternating load that fluctuates between positive and negative acts on the actuator 22 . When the actuator 22 is provided with a speed reducer having backlash, the operating noise of the actuator 22 due to rattling noise can be suppressed by reducing the engine rotation speed of the internal combustion engine 2 and then varying the compression ratio. Further, when the actuator 22 is hydraulically driven, the operating noise of the actuator 22 can be suppressed by the fluctuating pressure acting on the hydraulic chamber.

When the allowable power generation stop time T is equal to or longer than the predetermined allowable power generation stop time Tt, the load input (input torque) from the internal combustion engine 2 to the actuator 22 can be suppressed by switching the compression ratio after power generation is stopped.

Further, the hybrid vehicle changes the compression ratio of the internal combustion engine 2 from a low compression ratio (first compression ratio) to a high compression ratio (second compression ratio) when the internal combustion engine 2 is driven and the generator motor 1 is generating power. , the amount of reduction in the load of the internal combustion engine 2 is changed according to the remaining power of the driving force X of the actuator 22 .

More specifically, when the remaining power of the driving force X of the actuator 22 is equal to or less than a preset predetermined driving force X1 (first driving force X1), the hybrid vehicle operates at the first operating point P1 in the first operating region A1. When the operating point of the internal combustion engine 2 is switched to the second operating point P2 in the second operating region A2 while the generator motor 1 is generating electricity by driving the engine 2, the internal combustion engine 2 is stopped (the operating point of the internal combustion engine 2 is The first operating point P1 is changed to the fourth operating point P4), power generation by the generator motor 1 is stopped, and then the compression ratio is changed to the second compression ratio.

In the hybrid vehicle, if the remaining power of the driving force X of the actuator 22 is greater than a predetermined driving force X1 set in advance and is equal to or less than a predetermined driving force X2 (second driving force X2) set in advance, the generator motor 1 When switching the operating point of the internal combustion engine 2 from the first operating point P1 in the first operating region A1 to the second operating point P2 in the second operating region A2 during power generation, the operating point of the internal combustion engine 2 is changed to the first operating point P1 to the third operating point P3 to stop power generation by the generator motor 1 for charging the battery 3 or driving the drive motor 4 (power generation for maintaining the idle state of the internal combustion engine 2 continues). and then the compression ratio of the internal combustion engine 2 is changed to the second compression ratio. Then, when the compression ratio is changed to the second compression ratio, the operating point of the internal combustion engine 2 is changed from the third operating point P3 to the second operating point P2.

Note that the predetermined driving force X1 and the predetermined driving force X2 described above are values set by, for example, adaptation experiments using actual machines. Further, the predetermined driving force X2 is a larger value than the predetermined driving force X1.

In the hybrid vehicle, when the remaining power of the driving force X of the actuator 22 is larger than a predetermined driving force X2 set in advance, the operating point of the internal combustion engine 2 is set to the first operation in the first operating region A1 while the generator motor 1 is generating power. When switching from the point P1 to the second operating point P2 in the second operating region A2, the operating point of the internal combustion engine 2 is changed from the first operating point P1 to the second operating point P2, and while the generator motor 1 continues to generate power, The compression ratio of the internal combustion engine 2 is changed to the second compression ratio.

In the hybrid vehicle, when the drive force X of the actuator 22 has a small remaining power and the responsiveness deteriorates, it is possible to change the compression ratio in a short time by changing the compression ratio after the internal combustion engine 2 is stopped.

Even if the allowable power generation stop time T is shorter than the predetermined allowable power generation stop time Tt, if the drive force X of the actuator 22 is small and the responsiveness is poor, the internal combustion engine 2 is stopped and then the compression By changing the ratio, the compression ratio can be changed in a short time, and the power generation stop time of the generator motor 1 can be reduced.

The remaining power of the driving force X of the actuator 22 can be calculated from, for example, the input voltage of the actuator 22, the degree of deterioration of the actuator 22, the friction state, and the like.

When the input voltage to the actuator 22 is low, the remaining power of the driving force X of the actuator 22 is small. That is, the remaining power of the driving force X of the actuator 22 becomes smaller as the input voltage becomes lower.

As the actuator 22 deteriorates, its response time becomes slower (longer). That is, the remaining power of the driving force X of the actuator 22 becomes smaller as the response time of the actuator 22 becomes slower (longer).

When the oil temperature of the lubricating oil is low, the viscosity of the lubricating oil increases and the friction increases. Therefore, the remaining power of the driving force X of the actuator 22 becomes smaller as the oil temperature of the lubricating oil becomes lower.

FIG. 4 is a flow chart showing the control flow of the hybrid vehicle of the embodiment described above.

In step S1, it is determined whether or not there is a power generation request. For example, when the SOC of the battery 3 is equal to or lower than the power generation request threshold SOCr, which is smaller than the above-described predetermined SOCt, it is determined that there is a power generation request. If there is a power generation request in step S1, the process proceeds to step S2. If there is no power generation request in step S1, the process proceeds to step S11.

In step S11, it is determined whether the internal combustion engine 2 is in operation. If the internal combustion engine 2 is in operation in step S11, the process proceeds to step S12 to stop the internal combustion engine 2 and terminate the current routine. If the internal combustion engine 2 is not in operation in step S11, the current routine ends.

In step S2, the amount of operation of the accelerator pedal is detected. In step S3, a control command value for the drive motor 4 is calculated. In step S4, the electric power consumption E of the hybrid vehicle is calculated. At step S5, the SOC of the battery 3 is detected. In step S6, a target power generation amount (power generation amount O required for the internal combustion engine 2) is calculated.

In step S7, it is determined whether or not the internal combustion engine 2 is in operation. If the internal combustion engine 2 is in operation in step S7, the process proceeds to step S8. If the internal combustion engine 2 is stopped in step S7, the process proceeds to step S13. In step S13, the internal combustion engine 2 is started.

In step S8, it is determined whether or not the target power generation amount (power generation amount O required for the internal combustion engine 2) is greater than a predetermined value. If the target power generation amount is greater than the preset value in step S8, the process proceeds to step S9. If the target power generation amount is equal to or less than the preset value in step S8, the process proceeds to step S15.

In step S9, a power generation mode is set in which the internal combustion engine 2 is operated at maximum output to generate power.

In step S10, it is determined whether or not the current operating state of the internal combustion engine 2 is maximum output operation. If the operating state of the internal combustion engine 2 is the maximum output operation in step S10, the current routine is terminated. If the operating state of the internal combustion engine 2 is not the maximum output operation in step S10, the process proceeds to step S14. In step S14, the operating state of the internal combustion engine 2 is switched to maximum output operation. That is, in step S14, the target power generation mode is switched from power generation mode 2 to power generation mode 1. FIG. Note that step S14 will be described later.

In step S15, the internal combustion engine 2 is set to a power generation mode in which power is generated by high-efficiency operation that emphasizes fuel consumption.

In step S16, it is determined whether or not the current operating state of the internal combustion engine 2 is high efficiency operation. If the operating state of the internal combustion engine 2 is high-efficiency operation in step S16, the current routine is terminated. If the operating state of the internal combustion engine 2 is not high-efficiency operation in step S16, the process proceeds to step S17. In step S17, the operating state of the internal combustion engine 2 is switched to high efficiency operation. That is, in step S17, the target power generation mode is switched from power generation mode 1 to power generation mode 2. FIG. Note that step S17 will be described later.

FIG. 5 is a flowchart showing the flow of control when switching the target power generation mode, and is a subroutine corresponding to steps S14 and S17 in FIG. 4 described above. Since the control flow when switching from power generation mode 2 to power generation mode 1 and the control flow when switching from power generation mode 1 to power generation mode 2 are substantially the same, they will be described simultaneously using FIG.

In step S20, it is determined whether the SOC of the battery 3 is equal to or higher than a predetermined SOCt. If the SOC of the battery 3 is equal to or higher than the predetermined SOCt in step S20, the process proceeds to step S21. If the SOC of the battery 3 is not equal to or higher than the predetermined SOCt in step S20, the process proceeds to step S24.

In step S21, charging of the battery 3 or power generation by the generator motor 1 for driving the drive motor 4 is stopped (power generation for maintaining the internal combustion engine 2 in the idle state is continued). When switching from the power generation mode 1 to the power generation mode 2, in step S21, the operating point of the internal combustion engine 2 is set to the third operating point P3, and the load of the internal combustion engine 2 is reduced, and then the battery 3 is charged by the generator motor 1. stop generating electricity for

In step S22, the compression ratio of the internal combustion engine 2 is switched.
When switching from power generation mode 1 to power generation mode 2, in step S22, after switching the compression ratio of the internal combustion engine 2, the operating point of the internal combustion engine 2 is changed to the second operating point P2. When switching from power generation mode 2 to power generation mode 1, in step S22, after switching the compression ratio of the internal combustion engine 2, the operating point of the internal combustion engine 2 is set to the first operating point P1, and the load of the internal combustion engine 2 is increased.

In step S23, power generation by the generator motor 1 is started.

In step S24, it is determined whether or not the electric power consumption E of the hybrid vehicle is equal to or less than a predetermined electric power consumption Et. If the electric power consumption E of the hybrid vehicle is equal to or less than the predetermined electric power consumption Et in step S24, the process proceeds to S21. If the electric power consumption E of the hybrid vehicle is not equal to or less than the predetermined electric power consumption Et in step S20, the process proceeds to S25.

In step S25, it is determined whether or not the power generation amount O required of the internal combustion engine 2 is equal to or less than a predetermined power generation amount Ot. In step S24, if the amount of power generation O required of the internal combustion engine 2 is equal to or less than the predetermined amount of power generation Ot, the process proceeds to step S21. In step S20, if the power generation amount O required of the internal combustion engine 2 is not equal to or less than the predetermined power generation amount Ot, the process proceeds to S26.

In step S26, it is determined whether or not the allowable power generation stop time T is equal to or longer than a predetermined allowable power generation stop time Tt. In step S26, if the allowable power generation stop time T is equal to or longer than the predetermined allowable power generation stop time Tt, the process proceeds to S21. In step S26, if the allowable power generation stop time T is not longer than the predetermined allowable power generation stop time Tt, the process proceeds to S27.

In step S27, it is determined whether or not the remaining power of the driving force X of the actuator 22 is equal to or less than the predetermined driving force X1. In step S27, if the remaining power of the driving force X of the actuator 22 is equal to or less than the predetermined driving force X1, the process proceeds to S28. In step S27, if the remaining power of the driving force X of the actuator 22 is not equal to or less than the predetermined driving force X1, the process proceeds to S32.

In step S28, power generation by the generator motor 1 is stopped, and the internal combustion engine 2 is stopped. In step S29, the compression ratio of the internal combustion engine 2 is switched. In step S30, the internal combustion engine 2 is started at the operating point corresponding to the switched compression ratio. In step S31, power generation by the generator motor 1 is started.

In step S32, it is determined whether or not the remaining power of the driving force X of the actuator 22 is equal to or less than a predetermined driving force X2. In step S32, if the remaining power of the driving force X of the actuator 22 is equal to or less than the predetermined value X2, the process proceeds to S21. In step S32, if the remaining power of the driving force X of the actuator 22 is not equal to or less than the predetermined driving force X2, the process proceeds to S33.

In steps S33 and S34, the compression ratio is switched while the generator motor 1 continues to generate power. When switching from the power generation mode 1 to the power generation mode 2, in step S34, the operating point of the internal combustion engine 2 is set to the second operating point P2, and the load of the internal combustion engine 2 is reduced before switching the compression ratio. When switching from power generation mode 2 to power generation mode 1, the load of the internal combustion engine 2 is increased by setting the operating point of the internal combustion engine 2 to the first operating point P1 after switching the compression ratio in step S34.

When switching from the power generation mode 1 to the power generation mode 2, in step S34, the load of the internal combustion engine 2 is reduced within a range in which power generation can be continued, and then the compression ratio is switched. The operating point may be switched to the second operating point P2.

The embodiments described above relate to a hybrid vehicle control method and a hybrid vehicle control apparatus.

DESCRIPTION OF SYMBOLS 1... Electric motor for electric power generation 2... Internal combustion engine 3... Battery 4... Electric motor for drive 5... VCM
6 ECM
7 VCR controller 8 First in-vehicle network 9 Second in-vehicle network 11 Variable compression ratio mechanism 22 Actuator

Claims (6)

An internal combustion engine capable of changing the compression ratio by driving a generator motor to charge a battery and actuating an actuator, and the power generated by the generator motor or the power from the battery is used to drive the drive wheels. In a control method for a hybrid vehicle having a drive motor that
When switching the compression ratio of the internal combustion engine from a predetermined first compression ratio to a predetermined second compression ratio higher than the first compression ratio during power generation by driving the generator motor in the internal combustion engine,
when the power generation demand is large, changing the compression ratio of the internal combustion engine to the second compression ratio while generating power;
when the power generation request is small, changing the compression ratio of the internal combustion engine to the second compression ratio after charging the battery or stopping power generation by the generator motor for driving the drive motor;
The case where the power generation request is small is when the SOC of the battery is equal to or higher than a predetermined SOC, and the case where the power generation request is large is when the SOC of the battery is smaller than the predetermined SOC. A control method for a hybrid vehicle. The power generation request is small when the power consumption of the vehicle is equal to or less than a predetermined power consumption, and the power generation request is large when the power consumption of the vehicle is greater than the predetermined power consumption. 2. The method for controlling a hybrid vehicle according to claim 1 , wherein: When the power generation request is small, the power generation amount requested of the internal combustion engine is equal to or less than a predetermined power generation amount. When the power generation request is large, the power generation amount requested of the internal combustion engine is the predetermined power generation amount. 3. The method of controlling a hybrid vehicle according to claim 1 , wherein the amount is larger than the amount. The case where the power generation request is small means the case where the allowable power generation stop time, which is the time during which the vehicle can run even if power generation by the internal combustion engine is stopped by driving the generator motor, is equal to or longer than a predetermined allowable power generation stop time, The hybrid vehicle control method according to any one of claims 1 to 3 , wherein the case where the power generation request is large is the case where the power generation stoppage permissible time is shorter than the predetermined power generation stoppage permissible time. In changing the compression ratio of the internal combustion engine from the first compression ratio to the second compression ratio during power generation by driving the generator motor with the internal combustion engine,
changing the compression ratio to the second compression ratio after stopping the internal combustion engine when the remaining driving force of the actuator is equal to or less than a predetermined first driving force;
When the remaining driving force of the actuator is larger than the first driving force and equal to or less than a predetermined second driving force larger than the first driving force, the power generation by the generator motor is stopped, and then the changing the compression ratio of the internal combustion engine to the second compression ratio;
A compression ratio of the internal combustion engine is changed to the second compression ratio while power is generated by the generator motor when the remaining driving force of the actuator is larger than the second driving force. 5. A control method for a hybrid vehicle according to any one of items 1 to 4 . an internal combustion engine capable of changing the compression ratio by driving a generator motor, charging a battery, and operating an actuator;
a drive motor that drives drive wheels using power generated by the generator motor or power from the battery;
a control unit for switching a compression ratio of the internal combustion engine from a predetermined first compression ratio to a predetermined second compression ratio higher than the first compression ratio during power generation by driving the generator motor in the internal combustion engine; has
The control unit changes the compression ratio of the internal combustion engine while generating power when the demand for power generation is large, and changes the compression ratio of the internal combustion engine while generating power when the demand for power generation is small. changing the compression ratio of the internal combustion engine after stopping power generation by the generator motor,
The case where the power generation request is small is when the SOC of the battery is equal to or higher than a predetermined SOC, and the case where the power generation request is large is when the SOC of the battery is smaller than the predetermined SOC. A control device for a hybrid vehicle.

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