Control device and vehicle

Abstract

The present application provides a control device and a vehicle capable of switching an operation line of an internal combustion engine regardless of an operation point of the internal combustion engine, while reducing a sense of strangeness felt by an occupant. The control device is a control device of a vehicle provided with an internal combustion engine, a generator, a storage battery, and an electric motor, and in a case where the internal combustion engine is operating in a state where the internal combustion engine is not mechanically linked to drive wheels, when exhaust gas recirculation is performed and a rotational speed and a torque of the internal combustion engine are switched from a first state to a second state, it is determined whether to perform an assisted operation or a non-assisted operation, in the assisted operation, the rotational speed of the internal combustion engine is set to a rotational speed close to a first rotational speed compared to the second rotational speed, and the torque of the internal combustion engine is set to a second torque smaller than a first torque to operate the internal combustion engine, and the storage battery outputs electric power equivalent to an output insufficient with respect to the first torque, in the non-assisted operation, the rotational speed and the torque of the internal combustion engine are continuously set to the first rotational speed and the first torque to operate the internal combustion engine.

Description

Technical Field

[0001] This invention relates to a control device and a vehicle. Background Technology

[0002] Techniques for controlling the speed and torque of an internal combustion engine in a hybrid vehicle are known. For example, Japanese Patent Application Publication No. 2018-127961 discloses a hybrid vehicle that reduces fluctuations in speed and torque when operating conditions change. This technique switches operating conditions between multiple operating lines when the speed and torque of the internal combustion engine meet predetermined conditions. Summary of the Invention

[0003] However, in the technology described in Japanese Patent Application Publication No. 2018-127961, the timing for switching the operating line of the internal combustion engine is limited. Thus, in conventional technology, it is sometimes impossible to achieve the following: switching the operating line of the internal combustion engine regardless of its operating point, while simultaneously reducing discomfort felt by the occupants.

[0004] The present invention was made in consideration of such circumstances, and one of its objectives is to provide a control device and vehicle that can switch the operating line of the internal combustion engine regardless of the operating point of the internal combustion engine, while reducing the discomfort felt by the occupants.

[0005] The control device and vehicle of the present invention adopt the following structure.

[0006] (1): A control device according to one aspect of the present invention is a vehicle control device, the vehicle comprising: an internal combustion engine, a generator rotatable under the action of the internal combustion engine, a battery storing the electricity generated by the rotation of the generator, and an electric motor supplied with electricity from the battery and outputting driving force to the drive wheels, wherein, when the internal combustion engine is operating in a state where the internal combustion engine is not mechanically connected to the drive wheels, when switching from a first state to a second state, it is determined whether to perform auxiliary operation or non-auxiliary operation based at least on the output of the battery; in the first state, exhaust gas recirculation is performed, in which exhaust gas discharged from the internal combustion engine is recirculated back to the internal combustion engine, and the speed and torque of the internal combustion engine are set based on a first fuel economy optimal operating line taking into account the exhaust gas recirculation and the required output. The internal combustion engine is operated by obtaining a first speed and a first torque. In the second state, exhaust gas recirculation is not performed. In the auxiliary operation, the speed of the internal combustion engine is set to a speed close to the first speed compared to a second speed obtained based on a second fuel economy optimal operating line without considering exhaust gas recirculation and the required output. The torque of the internal combustion engine is set to a second torque that is smaller than the first torque to operate the internal combustion engine, and the battery outputs power equivalent to the output that is insufficient relative to the first torque. In the non-auxiliary operation, the speed and torque of the internal combustion engine are continued to be set to the first speed and the first torque to operate the internal combustion engine. The first fuel economy optimal operating line shows a larger torque for the same speed compared to the second fuel economy optimal operating line.

[0007] (2): In the above scheme (1), the output of the storage battery is calculated based on the charging rate and temperature. When the output of the storage battery is above a threshold, it is determined to perform the auxiliary operation. When the output of the storage battery is below the threshold, it is determined to perform the non-auxiliary operation.

[0008] (3): In the above (2) scheme, when the output of the battery becomes above the threshold after the non-auxiliary operation is performed due to the output of the battery being less than the threshold, the non-auxiliary operation is switched to the auxiliary operation.

[0009] (4): In any of the above schemes (1) to (3), the auxiliary operation is the operation of setting the speed of the internal combustion engine to the first speed.

[0010] (5): In any of the above schemes (1) to (4), the second torque is the torque corresponding to the first speed on the second fuel economy optimal operating line.

[0011] (6): Another aspect of the vehicle of the present invention comprises: an internal combustion engine; a generator rotatable under the action of the internal combustion engine; a battery storing electricity generated by the rotation of the generator; an electric motor supplied with electricity from the battery and outputting driving force to the drive wheels; and a control device, wherein, when the internal combustion engine is operating in a state where the internal combustion engine is not mechanically connected to the drive wheels, the control device determines, at least based on the charging state of the battery, whether to perform auxiliary operation or non-auxiliary operation when switching from a first state to a second state. In the first state, exhaust gas recirculation is performed, in which exhaust gas discharged from the internal combustion engine is recirculated back to the internal combustion engine, and the speed and torque of the internal combustion engine are set based on a first fuel economy optimal operating line taking into account the exhaust gas recirculation and the required output. The internal combustion engine is operated by obtaining a first speed and a first torque. In the second state, exhaust gas recirculation is not performed. In the auxiliary operation, the speed of the internal combustion engine is set to a speed close to the first speed compared to a second speed obtained based on a second fuel economy optimal operating line without considering exhaust gas recirculation and the required output. The torque of the internal combustion engine is set to a second torque that is smaller than the first torque to operate the internal combustion engine, and the battery outputs power equivalent to the output that is insufficient relative to the first torque. In the non-auxiliary operation, the speed and torque of the internal combustion engine are continued to be set to the first speed and the first torque to operate the internal combustion engine. The first fuel economy optimal operating line shows a larger torque for the same speed compared to the second fuel economy optimal operating line.

[0012] According to (1) to (5), the operating line of the internal combustion engine can be switched regardless of the operating point of the internal combustion engine, while reducing the discomfort felt by the passengers. Attached Figure Description

[0013] Figure 1 This is a diagram illustrating an example of the structure of vehicle M in this embodiment.

[0014] Figure 2 This is a diagram illustrating an example of the functional structure of a control device.

[0015] Figure 3 This diagram illustrates an example of the combination of engine torque and speed that achieves optimal fuel economy, representing both the case where EGR is enabled and the case where EGR is not enabled.

[0016] Figure 4 This is a diagram illustrating an example of the battery's output characteristics in relation to the battery's SoC and temperature.

[0017] Figure 5This is a flowchart illustrating an example of the process of an action performed by a control device.

[0018] Figure 6 This is a flowchart illustrating an example of how the engine control unit determines whether to set the engine to start.

[0019] Figure 7 This is a flowchart illustrating an example of how the EGR control unit determines whether to perform EGR.

[0020] Figure 8 This is a flowchart illustrating an example of a method by which the hybrid power control unit determines whether the engine can output low torque in a non-EGR environment.

[0021] Figure 9 This is a timing diagram illustrating the shift in engine output torque based on the EGR's execution status and the SoC's state. Detailed Implementation

[0022] Hereinafter, embodiments of the control device and vehicle of the present invention will be described with reference to the accompanying drawings.

[0023] [Overall Structure]

[0024] Figure 1 This diagram illustrates an example of the structure of the vehicle M according to this embodiment. The vehicle M shown is a hybrid vehicle capable of switching between series and parallel operation. In series operation, the engine and drive wheels are not mechanically connected; the engine's power is dedicated to generating electricity via a generator, which is then supplied to an electric motor for driving. In parallel operation, the engine and drive wheels are mechanically (or fluidly connected via a torque converter, etc.), and the engine's power can be transmitted to the drive wheels or used for generating electricity. Figure 1 The vehicle M with the structure shown can switch between series and parallel modes by engaging or disengaging the lock-up clutch 14.

[0025] like Figure 1 As shown, vehicle M is equipped with, for example, an engine 10, an EGR device 11, a first motor (generator) 12, a lock-up clutch 14, a gearbox 16, a second motor (electric motor) 18, a braking device 20, drive wheels 25, a PCU (Power Control Unit) 30, a battery 60, battery sensors such as voltage sensors, current sensors, and temperature sensors 62, a throttle opening sensor 70, a vehicle speed sensor 72, and a brake pedal position sensor 74. This vehicle M, as a drive source, at least includes an engine 10, a second motor 18, and a battery 60.

[0026] Engine 10 is an internal combustion engine that outputs power by burning fuels such as gasoline. Engine 10 is, for example, a reciprocating engine equipped with a combustion chamber, cylinder and piston, intake valve, exhaust valve, fuel injection device, spark plug, connecting rod, crankshaft, etc. Alternatively, engine 10 can also be a rotary engine.

[0027] EGR device 11 is a device that allows a portion of the exhaust gas after combustion in engine 10 to flow back into the combustion chamber of engine 10 as exhaust gas recirculation (EGR). EGR device 11 is configured to connect the intake passage and exhaust passage of the combustion chamber. EGR device 11 includes at least an EGR passage for allowing EGR gas to flow and an EGR valve for limiting the recirculation flow rate of EGR gas, and adjusts the recirculation flow rate of EGR gas (including zero, which is equivalent to isolating EGR gas) according to instructions from PCU 30. Figure 1 The illustration is omitted.

[0028] The first motor 12 is, for example, a three-phase alternator. The first motor 12 is connected to the rotor of the engine 10 via the output shaft (e.g., crankshaft) and uses the power output by the engine 10 to generate electricity. The output shaft of the engine 10 and the rotor of the first motor 12 are connected to the drive wheel 25 via a lock-up clutch 14.

[0029] The lock-up clutch 14 switches the state of the output shaft of the engine 10 and the rotor of the first motor 12 connected to the drive wheel 25 side and disconnected from the drive wheel 25 side, according to the instructions from the PCU 30.

[0030] Gearbox 16 is a transmission. Gearbox 16 changes the power output from engine 10 and transmits it to the drive wheels 25. The gear ratio of gearbox 16 is specified by PCU 30.

[0031] The second motor 18 is, for example, a three-phase AC motor. The rotor of the second motor 18 is connected to the drive wheel 25. The second motor 18 uses the supplied electricity and outputs power to the drive wheel 25. In addition, the second motor 18 uses the kinetic energy of the vehicle M to generate electricity when the vehicle M decelerates, and stores the generated electricity in the battery 60 via the second converter 34 and VCU described later.

[0032] The braking device 20 includes, for example, a brake caliper, a hydraulic cylinder that transmits hydraulic pressure to the brake caliper, and an electric motor that generates hydraulic pressure in the hydraulic cylinder. The braking device 20 may also include a backup mechanism for transmitting hydraulic pressure generated by the operation of the brake pedal to the hydraulic cylinder via the master hydraulic cylinder. It should be noted that the braking device 20 is not limited to the structure described above, and may also be an electronically controlled hydraulic braking device that transmits hydraulic pressure from the master hydraulic cylinder to the hydraulic cylinder.

[0033] PCU30, for example, includes a first converter 32, a second converter 34, a VCU (Voltage Control Unit) 40, and a control device 50. It should be noted that the structure in which these components are integrated into PCU30 is just one example; these components can also be configured separately.

[0034] The first converter 32 and the second converter 34 are, for example, AC-DC converters. The DC-side terminals of the first converter 32 and the second converter 34 are connected to a DC line DL. A battery 60 is connected to the DC line DL via a VCU 40. The first converter 32 converts the AC power generated by the first motor 12 into DC power and outputs it to the DC line DL, or converts the DC power supplied via the DC line DL into AC power and supplies it to the first motor 12. Similarly, the second converter 34 converts the AC power generated by the second motor 18 into DC power and outputs it to the DC line DL, or converts the DC power supplied via the DC line DL into AC power and supplies it to the second motor 18.

[0035] VCU40 is, for example, a DC-DC converter. VCU40 boosts the power supplied from battery 60 and outputs it to DC line DL.

[0036] The function of the control device 50 is described later. The battery 60 is, for example, a secondary battery such as a lithium-ion battery.

[0037] A throttle opening sensor 70 is installed on the accelerator pedal, which serves as an operating element for receiving acceleration instructions from the driver. It detects the amount of throttle pedal operation and outputs this as the throttle opening to the control device 50. A vehicle speed sensor 72 includes, for example, wheel speed sensors mounted on each wheel and a speed computer. It combines the wheel speeds detected by the wheel speed sensors to derive the vehicle speed (vehicle speed) and outputs it to the control device 50. A brake pedal pressure sensor 74 is installed on the brake pedal, which serves as an operating element for receiving deceleration or stop instructions from the driver. It detects the amount of brake pedal operation and outputs this as the brake pedal pressure to the control device 50.

[0038] Figure 2This diagram illustrates an example of the functional structure of the control device 50. The control device 50 includes, for example, an engine control unit 51, a motor control unit 52, a brake control unit 53, a battery / VCU control unit 54, and a hybrid power control unit 55. These components are implemented, for example, by executing programs (software) using a hardware processor such as a CPU (Central Processing Unit). Alternatively, some or all of these components can be implemented using hardware (including the circuitry) such as LSI (Large Scale Integration), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), and GPU (Graphics Processing Unit), or through a combination of software and hardware.

[0039] In addition, the engine control unit 51, motor control unit 52, brake control unit 53 and battery / VCU control unit 54 can each be replaced with a control device separate from the hybrid power control unit 55, such as an engine ECU (Electronic Control Unit), motor ECU, brake ECU and battery ECU.

[0040] The engine control unit 51 performs ignition control, throttle opening control, fuel injection control, and fuel cut-off control of the engine 10 according to instructions from the hybrid power control unit 55. For example, the engine control unit 51 receives command values ​​related to the speed and torque of the engine 10 from the hybrid power control unit 55 and performs control so that the engine 10 operates according to the command values.

[0041] The engine control unit 51 also includes an EGR control unit 51A. The EGR control unit 51A determines whether to perform EGR based on the state of the engine 10, and if it determines that EGR should be performed, it causes the EGR device 11 to perform EGR. Here, the state of the engine 10 includes, for example, the warm-up state of the engine 10, the execution state of feedback control of the air-fuel ratio, the execution state of fuel cut-off, and the pressure of the intake manifold (hereinafter also referred to as "intake manifold pressure").

[0042] The motor control unit 52 controls the switching of the first converter 32 and / or the second converter 34 according to the instructions from the hybrid power control unit 55.

[0043] The braking control unit 53 controls the braking device 20 according to the instructions from the hybrid power control unit 55.

[0044] The battery VCU control unit 54 calculates the SOC (State of Charge) and temperature of the battery 60 based on the output of the battery sensor 62 installed on the battery 60, and outputs this information to the hybrid power control unit 55. Additionally, the battery VCU control unit 54 activates the VCU 40 according to the instruction from the hybrid power control unit 55, causing the voltage of the DC line DL to rise.

[0045] The hybrid power control unit 55 determines the driving mode based on the outputs of the throttle opening sensor 70, vehicle speed sensor 72, and brake pedal pressure sensor 74, and outputs instructions to the engine control unit 51, motor control unit 52, brake control unit 53, and battery / VCU control unit 54 according to the driving mode. The hybrid power control unit 55 further determines command values ​​related to the engine speed and torque of the engine 10 in each driving mode, and sends the determined command values ​​to the engine control unit 51.

[0046] [Various driving modes]

[0047] The following describes the driving modes determined by the hybrid power control unit 55. The following driving modes exist.

[0048] (1) Series hybrid driving mode (ECVT)

[0049] In the series hybrid driving mode, the hybrid control unit 55 disengages the lock-up clutch 14, supplies fuel to the engine 10 to operate the engine 10, and provides electricity generated by the first motor 12 to the battery 60 and the second motor 18. Furthermore, the second motor 18 is driven using the electricity supplied from the first motor 12 or the battery 60, and the vehicle M is propelled by the power from the second motor 18. The series hybrid driving mode is an example of a mode in which the internal combustion engine operates without mechanically connecting it to the drive wheels.

[0050] (2) EV Driving Mode

[0051] In EV driving mode, the hybrid control unit 55 disengages the lock-up clutch 14 and uses the power supplied from the battery 60 to drive the second motor 18, thereby driving the vehicle M with the power from the second motor 18.

[0052] (3) Engine-driven driving mode (LU)

[0053] In engine-driven driving mode, the hybrid power control unit 55 engages the lock-up clutch 14, causing the engine 10 to consume fuel and operate, and transmitting at least a portion of the power output from the engine 10 to the drive wheels 25 to propel the vehicle M. At this time, the first motor 12 may or may not generate electricity.

[0054] (4)Regeneration

[0055] During regeneration, the hybrid power control unit 55 disengages the lock-up clutch 14, allowing the second motor 18 to generate electricity using the kinetic energy of the vehicle M. The electricity generated during regeneration is stored in the battery 60 or discarded through a waste-electricity operation.

[0056] [Summary of the actions performed by the control device 50]

[0057] Next, refer to Figure 3 Here is a summary of the actions performed by the control device 50. It should be noted that, unless otherwise specified, the actions of the control device 50 described below are assumed to be performed while the vehicle M is traveling in ECVT mode. In this case, the engine 10 is not directly connected to the drive wheels 25, therefore the control device 50 is not limited by vehicle speed and can select an unlimited number of combinations of speed and torque required to achieve the specified output of the engine 10.

[0058] Figure 3 This is a graph showing the torque and speed combination of the engine 10 that achieves optimal fuel economy, both when the EGR device 11 is performing EGR and when it is not performing EGR. Figure 3 In this diagram, MT represents the combination of the maximum torque achievable by vehicle M and its corresponding engine speed; TSL1 represents the combination of torque and engine speed for optimal fuel economy when EGR device 11 is operating (an example of the "first optimal fuel economy operating line"); TSL2 represents the combination of torque and engine speed for optimal fuel economy when EGR device 11 is not operating (an example of the "second optimal fuel economy operating line"); and EO represents the combination of torque and engine speed for achieving the output of engine 10. It should be noted that the output in this case is calculated by multiplying torque by engine speed.

[0059] Now, in Figure 3 In the case where the EGR device 11 is performing EGR and the torque and speed of the engine 10 are at point P1 (R1, T1) on the first fuel economy optimal operating line TSL1, the EGR control unit 51A determines that EGR has stopped and accordingly assumes that the EGR device 11 has stopped EGR. At this time, under normal circumstances, the control device 50 moves the combination of torque and speed from point P1 (R1, T1) to point P2 (R2, T2) on the second fuel economy optimal operating line that achieves the same output as point P1. However, in this case, since the speed of the engine 10 changes from R1 to R2, the occupants of the vehicle M may feel uncomfortable.

[0060] Therefore, in this embodiment, when the EGR device 11 stops EGR and the output of the battery 60 is above a threshold, the control device 50 keeps the engine speed unchanged and sets the torque to the torque corresponding to that engine speed on the second fuel economy optimal operating line TSL2. That is, the control device 50 moves the combination of torque and engine speed from point P1 (R1, T1) to point P3 (R1, T3) on the second fuel economy optimal operating line TSL2. In this case, the output of the engine 10 at point P3 (R1, T3) becomes R1×T3, which is smaller than the original output R1×T1. Therefore, the control device 50 performs auxiliary operation to make the battery 60 output electricity equivalent to the difference between the output R1×T1 before the movement and the output R1×T3 after the movement, R1×T1-R1×T3. Thus, the required output can be met without causing the occupants to feel any discomfort due to the change in engine speed, thereby achieving optimal fuel economy in non-EGR mode. Rotational speed R1 is an example of "first rotational speed", rotational speed R2 is an example of "second rotational speed", torque T1 is an example of "first torque", and torque T3 is an example of "second torque".

[0061] On the other hand, when the EGR device 11 stops EGR and the output of the battery 60 is less than the threshold, the control device 50 performs non-auxiliary operation to maintain the torque-speed combination at point P1(R1, T1). In this case, although the required output is met, the torque-speed combination is still at point P1(R1, T1), and the fuel efficiency is lower because it deviates from the second fuel economy optimal operating line TSL2.

[0062] In conventional technology, when the output of the battery 60 is less than a threshold and the control device 50 performs non-auxiliary operation, the non-auxiliary operation continues even after the output of the battery 60 recovers to above the threshold. However, in this embodiment, when the output of the battery 60 is less than the threshold and performs non-auxiliary operation, and then returns to above the threshold, the control device 50 switches from non-auxiliary operation to auxiliary operation. That is, the torque-speed combination is switched from point P1(R1, T1) to point P3(R1, T3), so that the battery 60 outputs power equivalent to the insufficient output. Therefore, it does not cause discomfort to the occupants of the vehicle M, and the torque-speed combination can be flexibly switched according to the output of the battery 60 to achieve optimal fuel economy.

[0063] It should be noted that, in the above description, the control device 50 maintains the rotational speed R1 at its original value during auxiliary operation. However, the present invention is not limited to this structure, and the control device 50 may also vary the rotational speed R1 within a range that is close to the level of comfort for the occupants of the vehicle M. Furthermore, in the above description, the control device 50 sets the torque T1 to torque T3. However, the present invention is not limited to this structure, and the control device 50 may generally set the torque T1 to a smaller value.

[0064] Furthermore, in the above description, "output of battery 60" refers to the output capacity of battery 60 calculated based on the SoC and temperature of battery 60. Figure 4 This is a diagram illustrating an example of the output characteristics of the battery 60 in relation to its SoC and temperature. Figure 4 The upper part indicates the output characteristics relative to the SoC of battery 60; the output of battery 60 increases monotonically relative to the SoC. On the other hand, Figure 4 The lower part indicates the output characteristics of the battery 60 with respect to its temperature. The output of the battery 60 increases monotonically before temperature T1, but takes a constant maximum value between temperature T1 and temperature T2, and decreases rapidly after temperature T2. That is, when the temperature of the battery 60 is high, even at high SoC, the output of the battery 60 takes a small value, which makes it easy to perform non-auxiliary operation.

[0065] [Flow of actions performed by control device 50]

[0066] Next, refer to Figure 5 This will explain the process of the actions performed by the control device 50. Figure 5 This is a flowchart illustrating the actions performed by the control device 50. The processing of this flowchart is performed every predetermined control cycle.

[0067] First, the engine control unit 51 determines whether to set the engine 10 to be on (step S100). The method for determining whether to set the engine 10 to be on is referred to [reference needed]. Figure 6 As will be described later. If it is determined that the engine 10 should not be set to start, the engine control unit 51 repeatedly performs the process of step S100. If it is determined that the engine 10 should be set to start, the engine control unit 51 activates the engine 10 by igniting the engine 10.

[0068] Next, the EGR control unit 51A determines whether to perform EGR (step S110). The method for determining whether to perform EGR is as follows: Figure 7As will be described later. If it is determined that EGR is not being performed, the control device 50 operates the engine 10 according to the second fuel economy optimal operating line TSL2 (step S120). Specifically, the hybrid power control unit 55 sets the speed and torque of the engine 10 to the intersection of the required output and the second fuel economy optimal operating line TSL2, and the engine control unit 51 operates the engine 10 according to that speed and torque.

[0069] On the other hand, when it is determined that EGR is to be performed, the control device 50 operates the engine 10 according to the first fuel economy optimal operating line TSL1 (step S130). Specifically, the hybrid power control unit 55 sets the speed and torque of the engine 10 to the intersection of the required output and the first fuel economy optimal operating line TSL1, and the engine control unit 51 operates the engine 10 according to the speed and torque.

[0070] Next, the EGR control unit 51A determines whether to stop EGR (step S140). The method for determining whether to stop EGR is the same as the method for determining whether to execute EGR. If it is determined that EGR should not be stopped, the control device 50 continues the operation of the engine 10 according to the first fuel economy optimal operating line TSL1.

[0071] On the other hand, if it is determined that EGR should be stopped, the EGR control unit 51A stops EGR, and the control device 50 determines whether the engine 10 can output low torque (step S150). The method for determining whether the engine 10 can output low torque is as follows: Figure 8 To be discussed later.

[0072] If it is determined that the engine 10 cannot output low torque, the control device 50 performs non-auxiliary operation to maintain the combination of torque and speed (step S170). That is, even if EGR stops, the control device 50 keeps the combination of torque and speed at the first fuel economy optimal operating line TSL1 and does not move to the second fuel economy optimal operating line TSL2. As a result, the required output is met without causing discomfort to the occupants of vehicle M, but fuel efficiency is reduced. Afterwards, the control device 50 executes the determination in step S150 again.

[0073] On the other hand, if it is determined that the engine 10 can output low torque, the control device 50 determines whether the output of the battery 60 is above a threshold (step S160). If it is determined that the output of the battery 60 is below the threshold, the control device 50 performs non-auxiliary operation to maintain the combination of torque and speed (step S170). Afterwards, the control device 50 performs the determination in step S150 again.

[0074] If the output of battery 60 is determined to be above a threshold, control device 50 performs auxiliary operation (step S180) by keeping the engine speed unchanged, setting the torque to the torque corresponding to that engine speed on the second fuel economy optimal operating line TSL2, and causing battery 60 to output power equivalent to the insufficient output. This satisfies the required output, preventing passengers from experiencing any discomfort due to changes in engine speed, and achieving optimal fuel economy in non-EGR mode. Figure 5 The processing of the flowchart has ended.

[0075] According to the flowchart described above, when EGR is executed and the engine 10 operates according to the first optimal fuel economy operating line, and then EGR stops, if the engine 10 can output low torque and the output of the battery 60 is above a threshold, the control device 50 performs auxiliary operation. On the other hand, if the engine 10 cannot output low torque or the output of the battery 60 is less than the threshold, the control device 50 performs non-auxiliary operation. Then, when the engine 10 can output low torque and the output of the battery 60 becomes above the threshold, the non-auxiliary operation is switched to auxiliary operation. Therefore, without causing discomfort to the occupants of vehicle M, the combination of torque and speed can be flexibly switched according to the output of the battery 60 to achieve optimal fuel economy.

[0076] It should be noted that, in Figure 5 In the flowchart, when determining whether to perform either auxiliary operation or non-auxiliary operation, two conditions are used: whether the engine 10 can output low torque and whether the output of the battery 60 is above a threshold. However, the present invention is not limited to this structure, and the determination can be based at least on the output of the battery 60.

[0077] Next, refer to Figure 6 This explains the method for determining whether to set engine 10 to be on. Figure 6 This is a flowchart illustrating an example of how the engine control unit 51 determines whether to set the engine 10 to be on.

[0078] First, the engine control unit 51 determines whether the required output is greater than the EV permitted output. The EV permitted output can be set to, for example, the maximum output, or an output such that the SoC's deceleration rate will not exceed a specified value. If it is determined that the required output is greater than the EV permitted output, the engine control unit 51 determines to set the engine to start (step S102).

[0079] On the other hand, if it is determined that the required output is below the EV permitted output, the engine control unit 51 determines whether there is an engine start request for implementing air conditioning (step S103). If it is determined that there is an engine start request for implementing air conditioning, the engine control unit 51 determines to set the engine to start; otherwise, if it is determined that there is no engine start request for implementing air conditioning, the engine control unit 51 determines to set the engine to stop (step S104). Thus, Figure 6 The processing of the flowchart has ended.

[0080] Next, refer to Figure 7 This explains the method for determining whether to execute EGR. Figure 7 This is a flowchart illustrating an example of how the EGR control unit 51A determines whether to perform EGR.

[0081] First, the EGR control unit 51A determines whether the engine 10 has completed warm-up (step S111). If it is determined that the engine 10 has not completed warm-up, the EGR control unit 51A determines that EGR will not be executed (step S116). On the other hand, if it is determined that the engine 10 has completed warm-up, the EGR control unit 51A then determines whether the air-fuel ratio feedback control is being executed (step S112).

[0082] If it is determined that the air-fuel ratio feedback control is not being executed, the EGR control unit 51A determines that EGR is not being executed. On the other hand, if it is determined that the air-fuel ratio feedback control is being executed, the EGR control unit 51A then determines whether the fuel cut-off of the engine 10 is not being executed (step S113).

[0083] If it is not determined that the fuel cut-off of engine 10 is not being executed, the EGR control unit 51A determines that EGR is not being executed. On the other hand, if it is determined that the fuel cut-off of engine 10 is not being executed, the EGR control unit 51A then determines whether the intake manifold pressure is within the specified range (step S114).

[0084] If the intake manifold pressure is determined to be outside the specified range, the EGR control unit 51A determines that EGR will not be executed. Conversely, if the intake manifold pressure is determined to be within the specified range, the EGR control unit 51A determines that EGR will be executed (step S115). Therefore, Figure 7 The flowchart processing is now complete. The conditions described above (S111 to S114) are prerequisites required for the normal execution of EGR.

[0085] It should be noted that, Figure 7The flowchart is related to the method for determining whether to execute EGR. By changing "execute EGR" in step S115 to "do not stop EGR", and changing "do not execute EGR" in step S116 to "stop EGR", it can also be used as... Figure 5 The EGR stop determination method is used in the flowchart.

[0086] Next, refer to Figure 8 This explains the method for determining whether the engine 10 can output low torque in a non-EGR environment. Figure 8 This is a flowchart illustrating an example of a method by which the hybrid power control unit 55 determines whether the engine 10 can output low torque in a non-EGR environment.

[0087] First, the hybrid control unit 55 determines whether EGR is not being executed (step S151). This condition is used to confirm that the current state is non-EGR. If it is determined that EGR is not being executed, the hybrid control unit 55 determines that the engine 10 cannot output low torque (step S153). On the other hand, if it is determined that EGR is not being executed, the hybrid control unit 55 determines whether the driver has not requested high output (step S152). Whether the driver has not requested high output can be determined, for example, by the throttle opening detected by the throttle opening sensor 70.

[0088] If it is not determined that the driver is not requesting high output, this means that the battery 60 is consuming a lot of power, or that the battery 60 will consume a lot of power in the future, and the battery 60 has little surplus to compensate for the torque reduction caused by the engine 10. Therefore, the hybrid power control unit 55 determines that the engine 10 cannot output low torque.

[0089] On the other hand, if it is determined that the driver does not require high output, this means that the consumption of battery 60 is low, or the consumption of battery 60 will decrease in the future, and the amount of torque that battery 60 can compensate for by the reduction in torque caused by engine 10 is large. Therefore, the hybrid power control unit 55 determines that engine 10 can output low torque (step S154). Thus, Figure 8 The processing of the flowchart has ended.

[0090] Next, refer to Figure 9 This will illustrate the shift in torque output by engine 10 in the exemplary scenario of this embodiment. Figure 9 This is a timing diagram illustrating an example of the shift in torque output by the engine 10 based on the EGR operation and the output of the battery 60. Similar to the flowchart above, Figure 9 The scenario assumes that vehicle M is in ECVT mode. Furthermore, it is assumed that the required output is constant for vehicle M.

[0091] First, before time t1, EGR is performed, the output of battery 60 is above threshold Th, and engine 10 outputs the speed and torque at the first fuel economy optimal operating line TSL1. Then, at time t1, EGR is stopped. At this time, the output of battery 60 is above threshold Th, so control device 50 performs an operation to change the torque to a value corresponding to the original speed at the second fuel economy optimal operating line TSL2, so that battery 60 outputs power to assist operation to compensate for any insufficient output.

[0092] Next, at time t2, the result of using the auxiliary operation of battery 60 is that the output of battery 60 is less than the threshold Th. At this time, control device 50 returns the torque to the value before t1 and performs non-auxiliary operation. That is, the speed and torque of engine 10 are set at the first fuel economy optimal operating line TSL1. Although the required output is met, fuel economy becomes inefficient. Then, at time t3, EGR is turned on again. At this time, the speed and torque of engine 10 are at the first fuel economy optimal operating line TSL1, thus meeting the required output and achieving efficient fuel economy.

[0093] Next, at time t4, EGR is stopped again. At this time, the output of battery 60 is less than the threshold Th, so control device 50 performs non-auxiliary operation to maintain the combination of torque and speed on the first fuel economy optimal operating line TSL1. Then, at time t5, the output of battery 60 becomes above the threshold Th, so control device 50 performs auxiliary operation to change the torque to a value corresponding to the original speed on the second fuel economy optimal operating line TSL2, so that battery 60 outputs power equivalent to the insufficient output.

[0094] According to the implementation described above, when EGR is stopped, auxiliary operation is performed according to the second optimal fuel economy operating line when the output of battery 60 is above a threshold. On the other hand, when the output of battery 60 is below the threshold, non-auxiliary operation is performed according to the first optimal fuel economy operating line. Then, when the output again exceeds the threshold, non-auxiliary operation is switched to auxiliary operation. Thus, the operating line of the internal combustion engine can be switched regardless of the engine's operating point, while reducing discomfort experienced by the occupants.

[0095] The implementation methods described above can be performed as follows.

[0096] A control device comprising:

[0097] A storage device containing a program; and

[0098] Hardware processor,

[0099] The hardware processor executes the program stored in the storage device to perform the following processing in the vehicle:

[0100] The vehicle includes: an internal combustion engine, a generator that can rotate under the action of the internal combustion engine, a battery that stores the electricity generated by the rotation of the generator, and an electric motor that is supplied with electricity from the battery and outputs driving force to the drive wheels.

[0101] When the internal combustion engine is operating without being mechanically connected to the drive wheels, the decision to perform auxiliary or non-auxiliary operation during the transition from the first state to the second state is based at least on the charging state of the battery.

[0102] In the first state, exhaust gas recirculation is performed, in which exhaust gas discharged from the internal combustion engine is recirculated back into the internal combustion engine, and the speed and torque of the internal combustion engine are set to a first speed and a first torque based on a first fuel economy optimal operating line that takes into account the exhaust gas recirculation and the required output, thereby causing the internal combustion engine to operate.

[0103] In the second state, the exhaust gas recirculation is not performed.

[0104] During the auxiliary operation, the internal combustion engine speed is set to a speed close to the first speed compared to a second speed obtained based on a second fuel economy optimal operating line and required output without considering exhaust gas recirculation. The internal combustion engine torque is set to a second torque that is less than the first torque to operate the internal combustion engine, and the battery outputs power equivalent to an output insufficient relative to the first torque.

[0105] During the non-auxiliary operation, the speed and torque of the internal combustion engine are continued to be set to the first speed and the first torque to cause the internal combustion engine to operate.

[0106] The first fuel economy optimal operating line shows greater torque for the same speed compared to the second fuel economy optimal operating line.

[0107] The above description illustrates specific embodiments of the present invention, but the present invention is not limited to such embodiments in any way, and various modifications and substitutions can be made without departing from the spirit of the present invention.

Claims

1. A control device, which is a vehicle control device, The vehicle includes: an internal combustion engine, a generator that can rotate under the action of the internal combustion engine, a battery that stores the electricity generated by the rotation of the generator, and an electric motor that is supplied with electricity from the battery and outputs driving force to the drive wheels. in, When the internal combustion engine is operating without being mechanically connected to the drive wheels, the decision to perform auxiliary or non-auxiliary operation during the transition from the first state to the second state is based at least on the battery output and torque output. In the first state, exhaust gas recirculation is performed, in which exhaust gas discharged from the internal combustion engine is recirculated back into the internal combustion engine, and the speed and torque of the internal combustion engine are set to a first speed and a first torque based on a first fuel economy optimal operating line that takes into account the exhaust gas recirculation and the required output, thereby causing the internal combustion engine to operate. In the second state, the exhaust gas recirculation is not performed. During the auxiliary operation, the internal combustion engine speed is set to a speed close to the first speed compared to a second speed obtained based on a second fuel economy optimal operating line and required output without considering exhaust gas recirculation. The internal combustion engine torque is set to a second torque that is less than the first torque to operate the internal combustion engine, and the battery outputs power equivalent to an output insufficient relative to the first torque. During the non-auxiliary operation, the speed and torque of the internal combustion engine are continued to be set to the first speed and the first torque to cause the internal combustion engine to operate. The first optimal fuel economy operating line shows a larger torque for the same speed compared to the second optimal fuel economy operating line.

2. The control device according to claim 1, wherein, The output of the battery is calculated based on the charging rate and temperature. When the output of the battery reaches or exceeds a threshold, it is determined to perform the auxiliary operation; when the output of the battery is less than the threshold, it is determined to perform the non-auxiliary operation.

3. The control device according to claim 2, wherein, If the battery output becomes above the threshold after the non-auxiliary operation was performed due to the battery output being less than the threshold, the non-auxiliary operation is switched to the auxiliary operation.

4. The control device according to any one of claims 1 to 3, wherein, The auxiliary operation is the operation in which the speed of the internal combustion engine is set to the first speed.

5. The control device according to any one of claims 1 to 3, wherein, The second torque is the torque corresponding to the first speed on the second optimal fuel economy operating line.

6. The control device according to claim 4, wherein, The second torque is the torque corresponding to the first speed on the second optimal fuel economy operating line.

7. The control device according to claim 1, wherein, When the control device determines that the internal combustion engine can output low torque as the torque output, and determines that the battery output is above a threshold, it decides to perform auxiliary operation.

8. A vehicle, comprising: internal combustion engine; A generator that can rotate under the action of the internal combustion engine; A storage battery that stores the electricity generated by the rotation of the generator; An electric motor, which is powered by the storage battery and outputs driving force to the drive wheels; and Control device, in, When the internal combustion engine is operating without being mechanically connected to the drive wheels, and the control device switches from the first state to the second state, it determines whether to perform auxiliary operation or non-auxiliary operation based at least on the output of the battery and the output of the torque. In the first state, exhaust gas recirculation is performed, in which exhaust gas discharged from the internal combustion engine is recirculated back into the internal combustion engine, and the speed and torque of the internal combustion engine are set to a first speed and a first torque based on a first fuel economy optimal operating line that takes into account the exhaust gas recirculation and the required output, thereby causing the internal combustion engine to operate. In the second state, the exhaust gas recirculation is not performed. During the auxiliary operation, the internal combustion engine speed is set to a speed close to the first speed compared to a second speed obtained based on a second fuel economy optimal operating line and required output without considering exhaust gas recirculation. The internal combustion engine torque is set to a second torque that is less than the first torque to operate the internal combustion engine, and the battery outputs power equivalent to an output insufficient relative to the first torque. During the non-auxiliary operation, the speed and torque of the internal combustion engine are continued to be set to the first speed and the first torque to cause the internal combustion engine to operate. The first optimal fuel economy operating line shows a larger torque for the same speed compared to the second optimal fuel economy operating line.

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